Device for setting predetermined ventilation parameters by a ventilator and / or for automatically displaying information regarding mechanical ventilation based on esophageal balloon pressure - Patent 7326933

Abstract

The device (15) according to the invention is provided with a pressure determination system (300) for determining the transpulmonary pressure (Ptp), in particular the transpulmonary pressure at the end of the expiratory phase (Ptp_ee) and / or the transpulmonary pressure at the end of the inhalation phase (Ptp_ei) based on an esophageal balloon catheter (45) insertable in the esophagus (34) including a balloon probe (46) for determining the esophageal balloon pressure (Peso), an esophageal balloon control system (400) for automatically monitoring and / or setting the appropriate filling of the balloon probe (46) of the esophageal balloon catheter (45) in vivo, and a ventilation controller (180) configured to adjust ventilation parameters (192A, 192B, 192C, 192D) specified by the ventilation device (10) and / or display information related to the mechanical ventilation based on the transpulmonary pressure (Ptp) determined by the pressure determination system (300).

Description

[Technical field]

[0001] The present invention relates to a device for setting predetermined ventilation parameters by a ventilator and / or for automatically displaying information related to mechanical ventilation based on esophageal balloon pressure.The present invention further relates to a ventilator comprising an esophageal balloon catheter having a balloon probe for determining the esophageal balloon pressure. [Background technology]

[0002] Esophageal balloon catheters equipped with a balloon probe for determining esophageal balloon pressure are particularly used during mechanical ventilation for determining transpulmonary pressure. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2014 / 037175 [Non-patent literature]

[0004] [Non-Patent Document 1] Mojoli et al.Crit.Care(2016) 20:98 [Non-Patent Document 2] Hotz et al.Respir.Care(2018)63(2):177-186 [Non-Patent Document 3] Benditt J. Resp.Care 2005,50:68-77 [Non-Patent Document 4] Lotti IA et al. Intensive Care Med. 1995,21:406-413 Summary of the Invention [Problem to be solved by the invention]

[0005] In today's common forms of mechanical ventilation, breathing gas is delivered to the patient at overpressure. Thus, during ventilation, the airway or alveolar pressure is greater than the pressure in the pleural cavity surrounding the alveoli, at least during the inspiration phase. During the expiration phase, the airways are not pressurized by the ventilator, so that the lung tissue relaxes and the airway or alveolar pressure falls. Under certain circumstances, this type of positive pressure ventilation can lead to unfavorable pressure conditions in the airways or alveoli at the end of the expiration phase, such as partial alveolar collapse. In this case, the collapsed lung volume must be re-expanded during the following breathing cycle, with a significant impairment of the functional residual capacity of the lungs, resulting in a decrease in oxygen saturation and possible permanent damage to the lung tissue.

[0006] To prevent alveolar collapse at the end of the expiratory phase, so-called positive end-expiratory pressure, commonly abbreviated as PEEP, is usually set during mechanical positive pressure ventilation, which often improves oxygen saturation.

[0007] When ventilating with PEEP, the ventilator applies a certain overpressure, i.e. PEEP, to the airway permanently, i.e. during both the inspiratory and expiratory phases, so that PEEP is still present after the end of the expiratory phase.

[0008] Ideally, PEEP is set so that during the expiratory phase, the intra-alveolar pressure does not fall below the pleural pressure, or at least so high that the pressure in the pleural space does not cause the alveolar tissue to collapse. In other words, PEEP prevents the transpulmonary pressure, which is the pressure difference between the intra-alveolar pressure and the pleural pressure, from falling below zero or below a negative threshold at which some of the alveoli begin to collapse.

[0009] On the other hand, too high a PEEP can have adverse effects, especially during the inspiratory phase, because the airway pressure is too high during the inspiratory phase, which stretches the lung tissue too much. Many studies have also shown that high PEEP can impair venous return to the heart, with associated adverse cardiovascular effects.

[0010] In principle, PEEP should be set to the prevailing transpulmonary pressure. However, it is not easy to determine the transpulmonary pressure of a patient during ventilation. Therefore, a balloon probe is placed in the esophagus of a patient requiring ventilation using an esophageal catheter to measure the pressure. By properly positioning and configuring the balloon, the pressure measured inside the balloon can be used to determine the approximate pressure in the pleural cavity.

[0011] International Publication No. 2014 / 037175 (Patent Document 1) discloses a technology for automatically setting the pressures set by a ventilation device, in particular positive end-expiratory pressure (PEEP) and maximum airway pressure, based on the esophageal balloon pressure, which is considered to be an index of transpulmonary pressure, i.e., between the alveolar pressure and the pressure in the pleural cavity.

[0012] In reality, the relationship between the pressure measured in the balloon catheter inserted in the esophagus and the pressure in the pleural cavity can change during ventilation for a variety of reasons that are usually not precisely identifiable.

[0013] Mojoli et al. Crit. Care (2016) 20:98 (Non-Patent Document 1) and Hotz et al. Respir. Care (2018) 63(2):177-186 (Non-Patent Document 2) recommend a procedure for calibrating an esophageal balloon catheter using a balloon catheter designed for measuring esophageal pressure. The purpose of the calibration is to optimally fill the balloon probe with air so that it reacts as sensitively as possible to changes in the pressure in the pleural cavity acting on the esophagus and reflects the pressure in the pleural cavity as closely as possible. However, since the calibration measurement procedure shown is relatively complex and sensitive, in practice only the optimal filling of the balloon probe is determined and set before the start of ventilation. This optimal filling is then maintained during ventilation and does not change. [Means for solving the problem]

[0014] The particular ventilation parameter may in particular be a pressure, such as a positive end-expiratory pressure (PEEP) or a maximum airway pressure (hereinafter also referred to as Paw_max), i.e. a typical ventilation parameter for a common ventilation mode, in particular a ventilation mode operating in a closed control loop with the aim of realizing a large degree of automation of ventilation, such as, for example, the adaptive assisted ventilation (ASV ventilation) or the INTELLiVENT-ASV mode developed by the applicant.

[0015] Additionally or alternatively, the device according to the invention may be designed to automatically display information about mechanical ventilation, in particular quantities related to the setting of other ventilation parameters and the selection of ventilation modes, such as pressures. Such information and magnitudes are often not directly measurable, but can be measured using an esophageal balloon catheter. An example of such a quantity is the transpulmonary pressure (hereinafter also referred to as Ptp), which can be used to determine whether alveolar collapse is a concern during ventilation. The pressure in the pleural cavity also falls into this category, and its automatic display on the display can provide useful information about the state of the thorax or chest wall.

[0016] Other examples of the presentation of information regarding ventilation include therapeutic recommendations to the operating personnel, in particular therapeutic recommendations derived from information provided by the esophageal balloon catheter. The therapeutic recommendations relate to recommendations for modification or readjustment of ventilation parameters used during ventilation, such as positive end-expiratory pressure (PEEP), maximum airway pressure (Paw_max), ventilation volume, ventilation pressure, etc., taking into account the ventilation status recorded during ventilation. If necessary, the therapeutic recommendations may also include a modification of the ventilation mode employed.

[0017] To facilitate monitoring, according to the invention, such relevant quantities or information can be automatically displayed if necessary, together with further information, such as information indicating how reliably such ventilation parameter determinations can currently be performed.

[0018] The device according to the present invention comprises a pressure determination system for determining the transpulmonary pressure, in particular the transpulmonary pressure at the end of the expiratory phase and / or the transpulmonary pressure at the end of the inhalation phase, based on an esophageal balloon catheter insertable into the esophagus, including a balloon probe for determining the esophageal balloon pressure, an esophageal balloon control system (400) for automatically monitoring and regulating the proper filling of the balloon probe of the esophageal balloon catheter in vivo, and a ventilation controller (180).

[0019] The ventilation controller is usually intended to control and regulate ventilation, in particular to control, regulate and monitor the ventilation process in a selected ventilation mode, and also to select or change the ventilation mode, if necessary, including largely automated ventilation modes based on a closed control loop for continuously adjusting important ventilation parameters during ventilation, as is the case for example with adaptive-assisted ventilation (ASV) and IN-TELLiVENT-ASV ventilation modes. The ventilation controller is especially designed to adjust the ventilation parameters specified by the ventilator and to display information about ventilation based on the transpulmonary pressure determined by the pressure determination system.

[0020] The pressure sensing system is configured to sense fluid pressure in the esophageal balloon and provide a signal representative of that pressure. Such esophageal balloon pressure signal generally needs to be taken into account during ventilation, particularly when adjusting certain ventilation parameters, such as positive end-expiratory pressure (PEEP) and maximum airway pressure (Paw_max), to suit the patient's physiological state. Thus, the pressure detection system is designed to provide an esophageal balloon pressure signal characteristic of the detected esophageal balloon pressure to a ventilation controller. The ventilation controller is then configured to receive such a signal from the pressure detection system.

[0021] The pressure sensing system combines information provided by at least one sensor, and often several different sensors, in the ventilator and / or esophageal balloon catheter. Thus, in accordance with an embodiment of the present invention, the pressure detection system also provides a suitable basis for controlling the esophageal balloon control system.

[0022] The pressure sensing system may be at least partially assigned to the ventilation controller. The pressure sensing system may also be assigned in whole or in part to the esophageal balloon control system. For example, components of the pressure sensing system that detect the pressure in the balloon probe of the esophageal balloon catheter may be assigned to the esophageal balloon control system. Additional components for use in determining the transpulmonary pressure based on the esophageal balloon pressure detected at the balloon probe of the esophageal catheter may be associated with the esophageal balloon control system or the ventilation control system. The pressure sensing system may also be designed as a substantially independent system with only appropriate interfaces for the ventilation controller and / or the esophageal balloon control system. Regardless of whether the pressure sensing system is assigned to the ventilation control system, the esophageal balloon control system, or is a largely independent system, the invention will be better understood by describing the pressure sensing system as an independent subsystem.

[0023] According to the invention, the ventilation controller is also designed for automatic control of the esophageal balloon control system. Additionally or alternatively, the esophageal balloon control system may also be designed for automatic control of the ventilation control system. The esophageal balloon control system may in particular be designed for controlling the ventilation controller to carry out certain operations, such as for example the so-called hold operation, which allows to measure quasi-static values ​​of the end-inspiratory and end-expiratory esophageal pressures.

[0024] The ventilation controller and the esophageal balloon control system may be specifically designed to be able to interact bidirectionally with each other.

[0025] The expression that the ventilation controller is designed for automatic control of the esophageal balloon control system indicates that the ventilation controller, in addition to its intended control and regulation functions on the ventilation device itself, also has control and regulation functions on the esophageal balloon catheter, in particular on its balloon probe. The ventilation controller can control the esophageal balloon control system to initiate predefined procedures, in particular filling the balloon probe with a measurement fluid, calibrating the balloon probe and / or continuously monitoring the filling state of the balloon probe. Additionally or alternatively, the ventilation controller can exert a control or regulation influence on the course of such procedures in the esophageal balloon control system. The control or regulation influence is realized, for example, by the ventilation controller providing the esophageal balloon control system with values ​​of currently set ventilation parameters, on the basis of which the esophageal balloon control system controls predefined control procedures of the esophageal balloon (such as the procedures mentioned above). In this way, an optimal interaction between the two control systems, the ventilation controller and the esophageal balloon control system, is realized, so that the procedures performed by the two systems are coordinated and synchronized.

[0026] The expression that the esophageal balloon control system is designed to automatically control the ventilation control system indicates that the esophageal balloon control system, in addition to transmitting a signal representative of the detected esophageal balloon pressure, also has a controlling and regulating function for the ventilation controller. The esophageal balloon control system can control the ventilation controller to initiate a given procedure. Additionally or alternatively, the esophageal balloon control system can influence the course of a particular procedure in the ventilation controller by controlling and regulating, for example by "freezing" the esophageal balloon control system or by fixing the currently set ventilation parameters, i.e. preventing such ventilation parameters from being changed by the ventilation controller for a certain period of time. In this way, an optimal interaction between the two control systems, the ventilation controller and the esophageal balloon control system, is achieved, so that the procedures performed by the two systems are coordinated and synchronized.

[0027] The ventilation controller can control the esophageal balloon control system to initiate a predetermined control procedure. Examples of such a control procedure include checking whether the balloon probe of the esophageal balloon catheter is properly filled with a measurement fluid (such as air), emptying the balloon probe and then refilling it with the measurement fluid, if necessary, and fully calibrating the balloon probe to set the amount of measurement fluid required for optimal filling of the balloon probe. Additionally or alternatively, the ventilation controller can intervene in the sequence of the predetermined control procedures in the esophageal balloon control system or completely take over control of the sequence of such control procedures. In this way, an optimal interaction between the two control systems, the ventilation controller and the esophageal balloon control system, is achieved, so that the procedures performed by the two systems are coordinated and synchronized. Also in this way, the control procedure of the esophageal balloon catheter can be performed while ventilation is being performed. Ventilation can be performed during the control procedure of the esophageal balloon catheter without interfering with the control procedure of the esophageal balloon catheter. This can include, for example, the ventilation controller inhibiting changes to ventilation parameters during ventilation while the control procedure of the esophageal balloon catheter is being performed.

[0028] In particular, the device according to the invention allows a more accurate consideration of the pressure in the pleural cavity by the esophageal balloon catheter and a more flexible adaptation of the measurements by the esophageal balloon catheter to changing environmental conditions during continuous ventilation, in particular in the case of largely automated ventilation. If the ventilation control system belonging to the ventilator and the esophageal balloon control system belonging to the esophageal balloon catheter are designed to be able to communicate with each other in two directions, this allows a continuous mutual monitoring of the two control systems and an adaptation of the whole system to changing environmental conditions during ventilation, without the need for manual intervention or interruption of ventilation to reconfigure or restart certain functions. In particular, adjustment of the filling level of the balloon probe with the measuring fluid can be performed without interrupting ventilation. The adaptation of the whole system also includes a complete (re)calibration of the esophageal balloon catheter without interrupting ventilation. This also applies when ventilation is performed using largely automated ventilation modes, as for example in the case of the adaptive-assisted (ASV) ventilation mode developed by the applicant or the IN-TELLiVENT-ASV.

[0029] The ventilation controller may also be configured to provide information important for the execution of a particular control procedure for the esophageal balloon catheter. This allows changes in ventilation parameters and measurement variables occurring during ventilation to be taken into account when executing the control procedure in the esophageal balloon control system. As an example, in some ventilation modes, the ventilation controller adjusts or resets the ventilation volume applied during mechanical ventilation for each breath. In such cases, the ventilation volume is not a constant ventilation parameter during ventilation, but a variable that changes from breath to breath. In some ventilation modes, the terms ventilation stroke, breathing cycle, and ventilation cycle are also used instead of breath. In the following, breath, ventilation stroke, breathing cycle, and ventilation cycle are used as synonyms. In some ventilation modes, the terms ventilation stroke, breathing cycle, and ventilation cycle are also used instead of breath. In the following, breath, ventilation stroke, breathing cycle, and ventilation cycle are used as synonyms. However, the ventilation volume applied to each breath affects other quantities, such as the ventilation pressure, which represents the pressure difference in the lungs between the end of the inspiration phase and the end of the expiration phase. It may also happen that the applied ventilation volume affects the control procedure in the esophageal balloon control system. For example, when calibrating the amount of measuring fluid in the balloon probe of an esophageal balloon catheter in vivo, it is assumed that the ventilation pressure does not change during the calibration. This means that the ventilation applied per breath should be kept as constant as possible even during the calibration. For this reason, the calibration of the balloon probe of an esophageal balloon catheter is only possible in ventilation modes in which the ventilation applied is kept constant. In the device proposed by the invention, the ventilation controller can transmit the ventilation applied per breath to the esophageal balloon control system, so that changes in the ventilation applied to the balloon probe can be taken into account when calibrating the esophageal balloon catheter. This can be done, for example, by relating the recorded difference between the esophageal balloon pressure at the end of the inspiration phase and the esophageal balloon pressure at the end of the expiration phase to the ventilation applied with the respective breath, for example by forming a ratio with the ventilation as the denominator. This makes it possible to calibrate the balloon probe during ventilation even in ventilation modes in which the ventilation is not fixed.

[0030] As mentioned above, in addition to the automatic setting of ventilation parameters such as PEEP and maximum airway pressure, some devices are designed to display information related to ventilation almost automatically. This includes displaying certain ventilation parameters such as transpulmonary pressure on the ventilator display. In this case, additional information can also be displayed, such as whether the esophageal balloon catheter is operating in normal mode or in a special mode such as a calibration procedure or a filling procedure.

[0031] Particular embodiments of the proposed device may have one or more of the optional features described below, which are expressly indicated below insofar as they are relevant to alternative designs. The following features may therefore be combined in any combination with any of the features described above or below, unless expressly excluded.

[0032] The ventilation controller may be designed to control / adjust the interaction with the esophageal balloon control system, such that the ventilation controller controls / adjusts the esophageal balloon control system according to pressure values ​​provided by the pressure sensing system. The interaction may in particular be two-way. The intelligence of the entire system may be primarily in the ventilation controller, which executes all control procedures, including control procedures related to the esophageal balloon catheter, such as calibrating the esophageal balloon catheter, monitoring the amount of fluid in the esophageal balloon, refilling the amount of fluid in the esophageal balloon, etc. In this case, the esophageal balloon control system is designed only to execute the control / adjustment commands provided by the ventilation control system. In an embodiment in which a pressure sensing system is at least partially associated with the esophageal balloon control system, the esophageal balloon control system may also be configured to provide a signal representative of the pressure sensed in the esophageal balloon.

[0033] The esophageal balloon control system may also be designed to control / regulate the interaction with the ventilation controller so as to execute esophageal balloon control procedures according to control commands provided by the ventilation controller. This interaction may also be bidirectional. The esophageal balloon control system itself may in any case have sufficient intelligence to be able to independently execute control / regulation procedures related to the esophageal balloon catheter, in particular procedures for calibrating the esophageal balloon catheter, procedures for monitoring the amount of fluid in the esophageal balloon or procedures for refilling the amount of fluid in the esophageal balloon. In that case, the ventilation controller only provides commands to the esophageal balloon control system for activating such procedures, which then executes these procedures independently, i.e. controls and / or regulates these procedures. Furthermore, in embodiments in which a pressure detection system is at least partially associated with the esophageal balloon control system, the esophageal balloon control system may also provide a signal reflecting the esophageal balloon pressure detected in the esophageal balloon (hereinafter also simply referred to as Peso). These measurement signals may, for example, already be executed, such that the signals sent for the ventilation controller already reflect the transpulmonary pressure.

[0034] Additionally or alternatively to the above-mentioned embodiments, the esophageal balloon control system may be configured to send predetermined esophageal balloon control signals to the ventilation controller. The ventilation controller may then be configured to set, control, and / or display predetermined ventilation parameters and / or ventilation modes according to these esophageal balloon control signals. In such embodiments, in particular, the esophageal balloon control system and the ventilation controller may be designed to bidirectionally communicate with each other. An esophageal balloon control signal as referred to herein does not refer to a pressure value sensed by the esophageal balloon or a signal representative of such a pressure value. Rather, an esophageal balloon control signal in the sense referred to herein is a control signal generated by the esophageal balloon control system and made available to the ventilation control system in addition to a signal related to the esophageal balloon pressure (hereinafter also referred to as the esophageal balloon pressure signal). Based on such esophageal balloon control signal, the ventilation control system controls / adjusts the ventilation mode occurring during ventilation and / or controls / adjusts certain ventilation parameters. "Exercising control / adjustment of influence" means that the ventilation controller brings about a change in a ventilation parameter or that the ventilation controller prevents such a change in a certain ventilation parameter for at least a certain period of time. This may be done, for example, so that the ventilation controller prevents changes in ventilation mode and / or blocks changes in ventilation parameters after the esophageal balloon control system sends an esophageal balloon control signal indicating that a calibration procedure for the esophageal balloon has been initiated. Such "freezing" of ventilation mode, or holding of ventilation parameters, may be cancelled after the initiated calibration procedure has been completed or aborted after the esophageal balloon control system sends a (further) esophageal balloon control signal. Similarly, the ventilation controller may use such esophageal balloon control signals to control / adjust the display of ventilation parameters (e.g., on a display of the ventilator) or to display such ventilation parameters altogether.For example, if there is a critical transpulmonary pressure or filling level of the balloon probe of the esophageal balloon catheter that is outside of acceptable specifications, a corresponding message may be displayed along with the recorded transpulmonary pressure or filling level of the balloon probe. Additionally or alternatively, treatment recommendations or other measures may be displayed, for example, if the transpulmonary pressure measured by the esophageal balloon is within a critical range or if the balloon probe is in an unacceptable filling state. Furthermore, a warning may be displayed on the ventilator display immediately after the esophageal balloon control system sends an esophageal balloon control signal indicating that an esophageal balloon calibration procedure is currently being activated.

[0035] The ventilation controller may be configured to not allow any changes in a given ventilation parameter and / or ventilation mode after activation or initiation of an esophageal balloon control procedure until the esophageal balloon control procedure has ended. In particular, an esophageal balloon control signal may indicate to the ventilation controller that the esophageal balloon control procedure has ended, such that the ventilation controller reverts to normal mode after receiving such an esophageal balloon control signal.

[0036] Data / parameters not directly related to the control of ventilation or automatic ventilation may be transmitted between the esophageal balloon control system and the ventilation control system. For example, ambient temperature and / or ambient pressure may be measured in either the esophageal balloon control system or the ventilation control system and transmitted to the ventilation control system or the esophageal balloon control system, such that sensors designed to determine each parameter need only be present once.

[0037] Furthermore, the ventilation controller may be configured to not allow changes to a given ventilation parameter and / or ventilation mode from a given time before the activation or start of an esophageal balloon control procedure until the esophageal balloon control procedure has finished or has not started within a given time. The finishing may mean both the completion of an esophageal balloon control procedure and the end of an esophageal balloon control procedure. In this embodiment, the synchronization between a change in ventilation parameters and / or a change in ventilation mode on the one hand and an esophageal balloon control procedure (especially a calibration procedure) on the other hand may be achieved by waiting to change the respective ventilation parameter and / or ventilation mode until a pending esophageal balloon control procedure has been completed successfully or unsuccessfully or has not been started within a given waiting time. This ensures that ventilation continues during an esophageal balloon control procedure while each esophageal balloon control procedure is performed under as consistent ventilation conditions as possible.

[0038] In further embodiments, the ventilation controller and / or esophageal balloon control system may be configured to generate an alert if a change in the predefined ventilation parameters and / or ventilation mode is forced after a predefined time point before the start of the esophageal balloon control procedure, in particular by a corresponding user input. The alert may be configured with an interruption of the change, such that further confirmation is required in response to the alert before the forced (e.g., by a user input) change in the predefined ventilation parameters / ventilation mode takes effect. This ensures that an input by the operator does not at least unintentionally disrupt the esophageal balloon control procedure and, as a result, impair its correct execution. Such an alert may be generated up to the completion or termination of the esophageal balloon control procedure.

[0039] Furthermore, the ventilation controller and / or the esophageal balloon control system may be configured such that an esophageal balloon control procedure is initiated at a predefined time, where if a change in a predefined ventilation parameter and / or ventilation mode is made within a predefined period of time before the initiation of the esophageal balloon control procedure, the esophageal balloon control system postpones the initiation of the esophageal balloon control procedure until the change in the ventilation parameter and / or ventilation mode is completed. This measure may also provide an effective synchronization between a change in the ventilation parameter and / or ventilation mode during ventilation on the one hand, and an esophageal balloon control procedure (e.g. a calibration procedure) on the other hand. In this case, the synchronization is achieved by postponing the initiation of the esophageal balloon control procedure until the change in the ventilation parameter or the change in the ventilation mode, respectively, has occurred. This ensures that if ventilation continues during the esophageal balloon control procedure, the esophageal balloon control procedure is performed under the same conditions according to the new ventilation parameters and / or new ventilation mode in this case.

[0040] In further embodiments, the ventilation controller and / or esophageal balloon control system may be configured such that changes in certain ventilation parameters and / or ventilation modes that occur after activation or initiation of an esophageal balloon control procedure are postponed until completion of the esophageal balloon control procedure. To some extent, the prioritization between ventilation and esophageal balloon control procedures is determined such that at least after initiation of an esophageal balloon control procedure or during the course of an esophageal balloon control procedure, the esophageal balloon control procedure takes precedence over ventilation, in particular changes in ventilation parameters such as PEEP or Paw_max, or changes in ventilation mode. In this sense, the ventilation controller can be said to "freeze" the set values ​​of ventilation parameters and / or ventilation mode as long as the esophageal balloon control procedure is active.

[0041] If certain changes in ventilation parameters or ventilation modes are to be made immediately, then these changes may be excluded and the postponement of the above-mentioned changes may be limited to only those ventilation parameters or ventilation modes that may be postponed.

[0042] In a further embodiment, the ventilation controller and / or the esophageal balloon control system may be configured such that an esophageal balloon control procedure is initiated according to a predefined time interval, where if a postponeable change in a predefined ventilation parameter and / or ventilation mode is made within a predefined period of time before the initiation of an esophageal balloon control procedure, the ventilation controller postpones the initiation of the change in the ventilation parameter and / or ventilation mode until the completion of the esophageal balloon control procedure. In this configuration, coordination between the ventilation controller and the esophageal balloon control system has already been performed with respect to a planned future esophageal balloon control procedure. For example, the esophageal balloon control system may transmit a control signal to the ventilation controller a predefined period of time before the initiation of a planned esophageal balloon control procedure, the signal indicating that the esophageal balloon control procedure will commence after the expiration of the predefined period of time. In response to receiving such a control signal, the ventilation control system may already have initiated a freezing of the ventilation parameters and / or ventilation mode (either as soon as the activation time has elapsed or, preferably, after the activation time has elapsed), so as to ensure that stable ventilation conditions exist when the esophageal balloon control procedure commences. If the esophageal balloon control procedure is initiated by the ventilation controller, the ventilation controller may activate freezing of ventilation parameters and / or ventilation mode without prior receipt of a corresponding control signal from the esophageal balloon control system.

[0043] It should be noted that initiating esophageal balloon control procedures according to predetermined time intervals does not necessarily require regular or uniform time intervals between successive esophageal balloon control procedures. For example, this expression is also intended to include embodiments in which esophageal balloon control procedures continue at irregular time intervals, so long as the esophageal balloon control system transmits a corresponding control signal to the ventilation control system at the appropriate time before the start of each esophageal balloon control procedure, and the signal signals the start of the esophageal balloon control procedure after the expiration of the predetermined period. The same applies when the esophageal balloon control procedures are initiated by the ventilation control system.

[0044] In a further embodiment, the pressure detection system may have a sensor designed to determine the esophageal balloon pressure, comprising an esophageal balloon catheter including a balloon probe inserted into the esophagus, and a device for detecting the pressure in the balloon probe in vivo. The pressure detection system may include a sensor designed in particular to determine the alveolar pressure and to determine the transpulmonary pressure based on the difference between the alveolar pressure and the esophageal balloon pressure. The sensor system for determining the alveolar pressure may be designed to determine the airway resistance and may have a sensor for detecting the gas flow in the airway, in particular at the end of the expiratory phase and / or the end of the inhalation phase. The sensor may then determine the alveolar pressure based on the gas flow and the airway resistance. The sensor system for determining the alveolar pressure may have an airway pressure sensor, for example, located at the tip of the tube of the ventilator or associated with the airway inlet valve of the ventilator to detect the airway pressure on the inhalation side.

[0045] In a further embodiment, the esophageal balloon control system may comprise a device for filling the balloon probe with the measurement fluid and / or for removing the measurement fluid from the balloon probe after the balloon probe has been placed in the esophagus. Such a device may comprise a pump device capable of pumping the measurement fluid into the balloon probe. If necessary, the measurement fluid may be pumped out of the balloon probe using the pump device. In this way, a fast and accurate filling of the balloon probe with a desired amount of measurement fluid and / or removal of a desired amount of measurement fluid from the balloon probe may be achieved. In particular, it is possible to pump the balloon probe at a negative pressure with respect to the ambient pressure. However, if the balloon probe is under excessive pressure with respect to its environment, the measurement fluid may be removed from the balloon probe without the aid of a pump device. In such a case, a device is provided for determining the flow of the measurement fluid exiting the balloon probe, also if this flow of the measurement fluid has not yet been sufficiently determined by controlling the pump device.

[0046] In a further embodiment, the introduction and / or removal of the measurement fluid from the balloon probe may be performed stepwise. For this purpose, the esophageal balloon control system is designed to gradually change the set amount of measurement fluid in the balloon probe, in particular to change the amount of measurement fluid in the balloon probe in one or more steps, thus gradually detects the esophageal balloon pressure at the amount of measurement fluid in the balloon probe set as a measurement point, and assigns the detected esophageal balloon pressure to the set amount of measurement fluid in the balloon probe. In this way, during each step of introducing the measurement fluid into the balloon probe and / or removing the measurement fluid from the balloon probe, at least one pair of measurements, in particular several pairs of measurements, may be obtained from the introduced / removed amount of measurement fluid and the respectively associated esophageal balloon pressure. Based on these pairs of measurements, information about the filling state of the balloon probe may be obtained and a corresponding control procedure may be activated and executed.

[0047] In further embodiments, the esophageal balloon control system and / or the ventilation controller may comprise at least one of a fluid volume monitoring system, a fluid filling system and a calibration system. In particular, when the esophageal balloon control system comprises at least one of a fluid volume monitoring system, a fluid filling system and a calibration system, the ventilation controller may be designed for bidirectional interaction with at least one of the fluid volume monitoring system, the fluid filling system and the calibration system. In this way, the ventilation controller may control the esophageal balloon control system to initiate a given monitoring procedure, a fluid filling procedure and / or a calibration procedure and / or control the sequence of the monitoring procedure, the fluid filling procedure and / or the calibration procedure. Please refer to the above examples for the possibilities realized by the bidirectional interaction between the esophageal balloon control system and at least one of the fluid volume monitoring system, the fluid filling system and the calibration system. In particular, it is also possible to fully synchronize the esophageal balloon control system with the ventilation controller or to incorporate it in the ventilation controller. In this way, the ventilation control system can control / adjust the ventilation of the patient over a longer period of time with respect to the information provided by the esophageal balloon catheter, in particular the esophageal balloon pressure, which approximately reflects the pressure in the pleural cavity. This includes the ability to perform specific control procedures on the esophageal balloon catheter, such as monitoring the correct filling of the balloon probe with measurement fluid, refilling or reinjecting the balloon probe with measurement fluid, withdrawing measurement fluid from the balloon probe, and / or calibrating the balloon probe to determine the amount of measurement fluid to be filled into the balloon probe.

[0048] In an embodiment, the ventilation controller and / or esophageal balloon control system may initiate a calibration procedure or a fluid volume monitoring procedure, and if desired, a fluid filling procedure, in the esophageal balloon control system in response to one of the following ventilation parameters or a change in one of the following variables being detected above a predetermined threshold during ventilation: (i) Responsive to a change in set point for at least one of the following ventilation parameters by above a predetermined threshold: a predetermined positive end-expiratory pressure (PEEP), a predetermined maximum airway pressure (Paw_max), a delivered tidal volume (Vt), a delivered tidal stroke volume (IE), a set ventilation rate (BR), (ii) (if not specified as a ventilatory parameter) responds to detection of a change equal to or greater than a threshold in at least one of the following variables: end-expiratory pressure (Pes_ee), difference between end-inspiratory pressure and end-expiratory pressure (Pes_ei-Pes_ee), esophageal pressure variation (Pes), chest wall compliance Ccw=Vt / (Pes_ei-Pes_ee). The variables referred to in (i) may be considered as recorded variables, provided that these variables are not specified as ventilation parameters in a particular ventilation mode, but may be freely adjusted or may be adjusted within specified limits.

[0049] The pressure recorded by the esophageal balloon probe at the end of expiration (Pes_ee) is often used as the reference pressure for this type of determination. This pressure is also called the "reference pressure" or "reference esophageal balloon pressure."

[0050] The calibration system is designed in particular for automatically adjusting the appropriate filling of the balloon probe of the esophageal balloon catheter, in which a precise filling level of the measuring fluid in the balloon probe of the esophageal balloon catheter is determined, at which the signal determined by the pressure detection system or pressure sensor for detecting the pressure in the balloon probe reflects as accurately as possible the pressure prevailing in the pleural cavity.

[0051] To determine the operational filling by calibration, the calibration system comprises a calibration controller designed to gradually change the amount of measurement fluid in the balloon probe, which thus gradually records the associated esophageal balloon pressure for the amount of measurement fluid in the balloon probe set as a measurement point and assigns it to the set amount of measurement fluid in the balloon probe. The esophageal balloon pressure may be measured by a pressure detection system or by a pressure sensor included in the calibration system.

[0052] If ventilation and / or esophageal balloon catheter conditions do not change over time, successful filling is usually achieved when the difference between the esophageal balloon pressure recorded at the end of the expiratory phase and the esophageal balloon pressure recorded at the end of the inspiratory phase is maximum for a given breath.

[0053] In an embodiment, the calibration system comprises the following components: - a device for placing a balloon probe in the esophagus and then filling the balloon probe with a measurement fluid; a pressure sensor for detecting the esophageal balloon pressure present in the balloon probe; a calibration controller designed to vary stepwise the amount of measuring fluid in the balloon probe, the calibration controller recording the esophageal balloon pressure detected by the pressure sensor at each of the amounts of measuring fluid in the balloon probe, the amounts of measuring fluid in the balloon probe being thus stepwise set as measuring points in the balloon probe and assigned to each set amount of measuring fluid in the balloon probe. With the expression "recording the esophageal balloon pressure" it is intended in particular to record the differential pressure between the pressure in the balloon probe recorded at the end of the inspiration phase and the pressure recorded at the end of the expiration phase.

[0054] If the ventilation controller is designed to automatically control the esophageal balloon control system in addition to its actual function of controlling / adjusting the ventilation mode or procedure performed by the ventilator during ventilation, the calibration system may be used to perform a calibration to determine the correct filling of the balloon probe of the esophageal balloon catheter and, if necessary, to freshly fill or refill the balloon probe with the measurement fluid with sufficient accuracy even under conditions of time-varying conditions occurring during ventilation. This is especially true if certain ventilation parameters or variables recorded during ventilation change during the calibration process. In this case, the ventilation controller may be designed to communicate these changes to the esophageal balloon control system.

[0055] For example, there are ventilation modes in which the tidal volume Vt delivered in a given ventilation stroke is not constant, but varies from ventilation stroke to ventilation stroke. This change in the tidal volume Vt usually affects the difference dPeso between the esophageal balloon pressure Peso_ei measured at the end of the inspiration phase and the esophageal balloon pressure Peso_ee measured at the end of the expiration phase of the breath. This effect may be compensated for if the change in the tidal volume Vt is included in the determination of the difference to be maximized during the calibration. Thus, in one embodiment of the present invention, the calibration controller relates the difference dPeso between the esophageal balloon pressure at the end of the inspiration phase Peso_ei and the esophageal balloon pressure at the end of the expiration phase Peso_ee to the tidal volume Vt delivered in the respective ventilation stroke, and can determine as the operational filling of the balloon probe the amount of measuring fluid in the balloon probe at which the quotient dPeso / Vt thus obtained is maximized. As a result, the maximization of the ratio dPesoA / t is less dependent on breath-to-breath variations than dPeso. However, at a constant tidal volume Vt, it corresponds to maximizing dPeso.

[0056] If the tidal volume Vt varies from breath to breath, this means that the recorded value of the pressure difference dPeso is related to the respective applied tidal volume Vt. This allows to obtain a value of the pressure difference of the esophageal balloon pressure that is independent of the ventilation depth. This measure improves the accuracy of the calibration. Since the tidal volume Vt is a quantity provided by the ventilation controller, the bidirectional communication between the proposed ventilation controller (part of the ventilator) and the calibration system (part of the esophageal balloon control) allows the calibration of the esophageal balloon catheter under conditions that were not possible before. Since the ventilator provides the calibration system with additional information (tidal volume), the accuracy of the calibration can be improved, and therefore also the accuracy of the pressure measurement provided by the balloon catheter inserted in the esophagus. The calibration system allows a more accurate reproduction of the pressure spreading in the pleural cavity through the balloon catheter and a faster response of the measurements to changing environmental conditions during continuous ventilation. This allows the balloon catheter to be calibrated during ventilation without the need to interrupt ventilation. This is also true when ventilation is performed using largely automated ventilation modes, such as, for example, the adaptive-assist (ASV) ventilation mode developed by the applicant, or IN-TELLiVENT-ASV.

[0057] In an embodiment, the calibration controller is designed to vary the amount of measurement fluid in a monotonic manner starting from a starting value in at least two steps until a final value is reached to approach each measurement point.

[0058] The calibration system may in particular comprise a device for removing the measurement fluid from the balloon probe (fluid ejection device) after the balloon probe is placed in the esophagus. Both the device for filling the balloon probe with the measurement fluid after the balloon probe is placed in the esophagus and the device for removing the measurement fluid from the balloon probe after the balloon probe is placed in the esophagus may comprise one or more valves arranged in a conveying line for measuring the fluid in fluid communication with the balloon probe. In case the measurement fluid in the balloon probe is under overpressure, the fluid ejection device may be implemented simply by controlling a valve in a fluid line in fluid communication with the balloon probe.

[0059] The device for filling the balloon probe with a measurement fluid after positioning the balloon probe in the esophagus may comprise a pump device for feeding the measurement fluid into the balloon probe. In this case, the pump device may be designed to remove (pump) the measurement fluid from the balloon probe. The fluid ejection device may comprise a pump device.

[0060] In a further embodiment, the device for filling the balloon probe with the measurement fluid and / or the device for removing the measurement fluid from the balloon probe may have a flow sensor, in particular a mass flow sensor, designed to determine the amount of measurement fluid introduced into the balloon probe and / or the amount of measurement fluid removed from the balloon probe. For example, the amount of measurement fluid introduced into or removed from the balloon probe may be determined by integrating the flow rate measured by the flow sensor over a period between a start time and an end time. When using a flow sensor that determines the flow rate of the measurement fluid based on a differential pressure, the flow sensor may also be used to detect the esophageal balloon pressure prevailing in the balloon probe. It is also possible to provide a separate pressure sensor.

[0061] The calibration controller may be implemented as an independent component "in hardware". Alternatively, the calibration controller may also be implemented as a computer program product, i.e. by a corresponding software program running on a processor, in particular a microprocessor or microcontroller. In this case, the software may be stored on a suitable local or network accessible storage medium. The software comprises instructions coded as a computer program, which, when loaded into the memory of the processor and translated into a machine language, causes the processor to carry out the procedures described in more detail herein. Of course, a mixture of implementations in hardware and in software is also conceivable. The microprocessor or microcomputer may be part of the control system of the calibration system.

[0062] By the expression "monotonous", it is intended that the amount of measuring fluid in the balloon probe always changes in the same direction during the measurement cycle. This means that the amount of measuring fluid continues to decrease or increase during the measurement cycle between a start value and an end value to reach each subsequent measurement point. The approach of the measurement points between the start value and the end value defines the measurement cycle. The start and end values ​​of the measurement cycle may be defined by a predetermined amount of measuring fluid supplied to or flowing out of the balloon probe. Alternatively, it is also conceivable to define the start and end values ​​by a predetermined value of the pressure measured at the balloon probe. The same applies to the individual measurement points that are approached between the start and end values ​​of the measurement cycle. At least, it has been found that it is easier and quicker to always drain or introduce a predetermined amount of measuring fluid from or into the balloon probe when approaching successive measurement points between the start and end values ​​(where the start and end values ​​may be included).

[0063] The monotonically passing through the measurement range between the start and end values ​​in the measurement cycle proposed by the invention accelerates the calibration considerably. This is due in particular to the fact that successive measurement points in the measurement cycle approach one after the other directly, starting from the start value and at least up to the end value. In particular, intermediate steps for evacuating the balloon probe and / or for setting exactly reproducible initial conditions for the individual measurement points during the calibration are no longer required. Furthermore, there is no longer any need to wait for equalization or relaxation steps. Surprisingly, it has been shown that the calibration is not affected in any negative way, at least not unacceptably, by omitting identical procedures with the same initial conditions for each measurement point. In particular, hysteresis effects (if present) seem to have approximately the same effect for all measurement points in the measurement cycle and therefore do not interfere with the calibration.

[0064] Particular embodiments of the calibration system proposed herein may have one or more of the optional features described below. Insofar as a feature is relevant only for alternative designs, this is expressly indicated below. It is therefore understood that the following features may be combined in any manner with the features described above or below, unless expressly excluded.

[0065] As mentioned above, the calibration system may further comprise a fluid ejection device designed to eject the measurement fluid from the balloon probe. The calibration controller controls the fluid ejection device to approach each measurement point such that the amount of measurement fluid in the balloon probe decreases monotonically in at least two steps from a starting value until a final value is reached. The control may be performed, for example, by temporarily opening a valve in a delivery line in fluid communication with the balloon probe. Active pumping using a suitable pump device is also conceivable.

[0066] The calibration controller may further be designed to control the device for filling the balloon probe with the measurement fluid at least in the first measurement cycle to fill the balloon probe with the measurement fluid such that the amount of measurement fluid introduced into the balloon probe is greater than the upper limit of the measurement range assigned to the measurement cycle between the start value and the end value. In this case, the start value defining the start of the measurement cycle is reached only after the first amount of measurement fluid has been released from the balloon probe. The calibration controller may control the device for filling the balloon probe to initially fill the balloon probe with an amount of measurement fluid that is greater than the amount of measurement fluid corresponding to the start value. The calibration controller may then control the fluid release device to release the measurement fluid from the balloon probe until the amount of measurement fluid in the balloon probe corresponds to the start value.

[0067] These actions bring the balloon probe into a predefined overstretched state before the start of the next measurement cycle, which allows the measurement cycle to cover in practice the entire measurement range available when the pressure measured by the balloon probe varies approximately linearly with the amount of measurement fluid in the balloon probe. In the procedure of overstretching the balloon probe before approaching the starting value, the pressure measured by the balloon probe decreases approximately linearly with the amount of measurement fluid in the balloon probe during the measurement cycle, at least in the intermediate range. This linear decrease defines the range commonly used as the measurement range of an esophageal balloon catheter between the upper filling of the measurement fluid in the balloon probe and the lower filling of the measurement fluid in the balloon probe.

[0068] Since the measurements are performed in vivo, i.e. with a balloon probe placed in the patient's esophagus, the slope of the esophageal balloon pressure / volume of measurement fluid curve in the linear portion used as the measurement range is determined to be greater by the distensibility of the esophagus and less by the distensibility of the balloon probe: the esophagus, while retaining approximately the same distensibility, becomes less stretched in the linear portion as the volume of measurement fluid decreases and / or its cross section decreases as the volume of measurement fluid decreases.

[0069] In the region above the linear portion of the measurement range, at least if the diameter of the balloon probe is large enough, the maximum esophageal distension value is reached. After that, the balloon probe does not distend any further if the amount filled in the fluid increases. As a result, the pressure in the esophageal balloon increases more rapidly with an increase in the measurement fluid volume than in the linear portion of the measurement range. As a rule, at least in the first measurement cycle, the starting value of the measurement fluid volume is set so that the starting value of the measured esophageal balloon pressure is in the range above the linear portion of the measurement range.

[0070] In a further embodiment, the calibration controller may be designed to perform at least two measurement cycles in succession, the measurement ranges of the at least two successive measurement cycles may be different, in particular, the previous measurement cycle may define the measurement range of the subsequent measurement cycle.

[0071] For example, in a preceding measurement cycle, a first measurement range between a first start value and a first end value may be traversed to find an approximately linear range in which the esophageal distensibility remains approximately the same, and then in a subsequent measurement cycle, a finer gradation of measurement points may be performed between a second start value and a second end value, both of which are within the linear range.

[0072] The calibration controller may further be designed to set the distance between successive measurement points differently in a preceding measurement cycle and a succeeding measurement cycle, the expression "distance between measurement points" indicating the difference between corresponding amounts of measurement fluid in the balloon probe.

[0073] For example, in a preceding measurement cycle, a relatively large distance between successive measurement points may be set to identify a range in which the esophageal balloon pressure determined at the esophageal balloon catheter varies approximately linearly with the amount of measurement fluid in the balloon probe, and in subsequent measurement cycles, smaller step sizes may be traversed through this linear range between the corresponding maximum and minimum amounts of measurement fluid to find the optimal filling amount of measurement fluid for the esophageal balloon catheter.

[0074] Furthermore, the calibration controller may be designed to adaptively determine a step size between successive measurement points within a measurement range in a measurement cycle, such that such adaptive determination of the step size may be implemented using a gradient method, such as, for example, a Newton algorithm.

[0075] In the case of several successive measurement cycles, it is advantageous to perform a certain "overstretch" of the balloon probe, i.e., an initial introduction of an amount of measurement fluid before each measurement cycle that is greater than the amount of measurement fluid corresponding to the start value of the respective measurement cycle. The calibration controller may then be designed so that the measurement fluid from the balloon probe is not completely emptied between the preceding and the following measurement cycle. In such an embodiment, there is in particular no complete evacuation of the cavity or volume enclosed by the balloon probe between successive measurement cycles. Rather, exploitation is made of the fact that, starting from an arbitrary initial value, if an amount of measurement fluid greater than that required for the initial value is initially introduced into the balloon probe, the exact amount of measurement fluid in the balloon probe before the start of each measurement cycle is not important, since the overstretching thus produced depends much more on the amount of measurement fluid introduced into the balloon probe than on the initial condition at which filling is started. In addition, when the measurement fluid is removed from the balloon probe to achieve the start value of the subsequent measurement cycle, the exact degree of overstretching of the balloon probe is often not important at all, since the desired start value for each measurement cycle is determined from the recorded esophageal balloon pressure.

[0076] However, to improve accuracy, the balloon probe may be set to a predefined "zero state" before the start of a measurement cycle, or at least before the start of the first measurement cycle in the case of several consecutive measurement cycles, for example by pumping or draining the measurement fluid from the balloon probe until a predefined negative pressure (for example -20 hPa relative to ambient pressure) is reached. In this way, it can be ensured that the calibration procedure starts from a predefined initial state of the balloon probe, for example with the balloon probe having a fully folded configuration. Starting from this zero state, the measurement fluid may be introduced or pumped into the balloon probe until the balloon probe is overfilled to a predefined pressure above the start value of the first measurement cycle. From this state, the calibration procedure may then be performed in the manner described above by successively approaching several measurement points in a monotonic manner between the start and end values.

[0077] In a further embodiment, the calibration controller may be designed to determine a measurement value of the esophageal balloon pressure at the end of the inspiratory phase and a measurement value of the esophageal balloon pressure at the end of the expiratory phase for each measurement point, i.e., for each set amount of measurement fluid in the balloon probe between the start and end values ​​of the measurement cycle (including the start and end values, if desired), and then determine the difference between the esophageal balloon pressure at the end of the inspiratory phase and the esophageal balloon pressure at the end of the expiratory phase.

[0078] The calibration controller may be designed to determine, for a range between a start value of the amount of measurement fluid in the balloon probe and an end value of the amount of measurement fluid in the balloon probe (including the start and end values, if desired), a maximum value of the difference between the esophageal balloon pressure at the end of the inspiration phase and the esophageal balloon pressure at the end of the expiration phase (maximum pressure). The amount of measurement fluid in the balloon probe corresponding to the maximum pressure then corresponds to an optimal filling of the balloon probe, i.e., the amount of measurement fluid in the balloon probe with which ventilation should be performed.

[0079] Further, the calibration controller may be designed to determine a measurement of the esophageal balloon pressure at the end of the inspiratory phase and a measurement of the esophageal balloon pressure at the end of the expiratory phase while ventilation continues for each measurement point between the start and end values.

[0080] Thus, there is no need to interrupt an ongoing ventilation or breathing cycle in order to determine the measurements of the esophageal balloon pressure. In particular, there is no need to set a dead time during which the airway is closed so that the flow of ventilation or breathing gas stops in order to determine these measurements. Thus, the ventilation of the patient can continue without any changes while the calibration or recalibration of the esophageal balloon catheter is performed. This is a great advantage from the patient's point of view, not only because interruptions or disturbances in ventilation should be avoided, but also because the calibration of the esophageal balloon catheter is performed under conditions as close to reality as possible.

[0081] Further, the calibration controller may be designed to compare the difference determined for the measurement points between the esophageal balloon pressure at the end of the inhalation phase and the esophageal balloon pressure at the end of the exhalation phase, and then, if the pressure difference determined for the measurement points is within a predetermined variation range relative to the maximum value of the pressure difference for a number of consecutive measurement points, determine the amount of measurement fluid corresponding to optimal filling of the balloon probe as the amount of measurement fluid having a predetermined distance from the minimum amount of measurement fluid in the balloon probe (lower edge) and / or from the maximum amount of measurement fluid in the balloon probe (upper edge) for which the detected pressure difference is within the variation range.

[0082] For example, the amount of measurement fluid corresponding to the optimal filling of the balloon probe may be determined to be closer to the lower edge of such range having approximately equal pressure difference near the maximum value than the upper edge. The amount of measurement fluid in the balloon probe corresponding to the optimal filling of the balloon probe ("optimum filling") may be greater than the amount of measurement fluid corresponding to the lower edge of the region having approximately the same pressure difference, for example, by ⅓ of the distance between the amount of measurement fluid in the balloon probe corresponding to the upper edge of the region having approximately the same pressure difference and the amount of measurement fluid in the balloon probe corresponding to the lower edge of the region having approximately the same pressure difference.

[0083] In particular, the calibration controller may be designed to determine, for each measurement point between a start value and an end value (including the start value and the end value, if applicable), a number of measurements, in particular a number of pairs of measurements for the esophageal balloon pressure at the end of the inspiration phase and the esophageal balloon pressure at the end of the expiration phase. This usually occurs in successive ventilation cycles. The calibration controller may then determine the average and statistical variance of the measurements based on the multiple measurements per measurement point, or a quantity derived from the measurements, in particular the difference (pressure difference) between the esophageal balloon pressure at the end of the inspiration phase and the esophageal balloon pressure at the end of the expiration phase, and determine the number of measurements per measurement point such that the obtained average can be considered statistically significant.

[0084] In general, the greater the statistical variability of the measurements obtained, the more respiratory cycles are used to determine the pressure difference measurement assigned to a particular measurement point. For example, cardiogenic vibrations or movements may play a role here. Such effects may be better distinguished by increasing the number of respiratory cycles per measurement. In particular, the arithmetic mean may be used as the mean. However, other types of averaging may also be used, for example the geometric mean.

[0085] The statistical variance can be represented in particular by the Gaussian standard deviation. It is therefore conceivable to define a 2 sigma level as statistically significant, i.e. a Gaussian standard deviation of 95% or more is considered significant. In another variant, one can proceed adaptively to determine the variance, for example by using the change in the mean value after a new measurement as a measure of significance for a particular measurement point. The smaller the change in the mean value after a particular measurement, the higher the significance. The measurement may be repeated for each measurement point until the change in the mean value after the last measurement is smaller than a predefined threshold. Then one can proceed to the next measurement point, for example by removing a predefined amount of measurement fluid from the balloon probe.

[0086] In a further embodiment, the calibration controller may be designed to monitor, for each measurement point between the start and end values, whether the respective measurement value is affected by external circumstances (if the pressure difference per measurement point is measured several times for each of these measurements) and to reject the respective measurement value if such an external situation is detected. Such external circumstances may include, for example, the swallowing efforts of the patient. Instead of the entire calibration being discarded or stopped, only the measurements affected by the external circumstances may be discarded. In particular, new measurements for the measurement points may be determined immediately after. The calibration procedure may then continue as normal. Thus, artificial measurements are eliminated "in real time" without the need to interrupt or halt the calibration procedure for a longer period. Restarting the entire calibration after detecting an external situation may be significantly longer and may lead to, for example, in the case of a swallowing effort by the patient during one or more measurements, a swallowing effort being triggered again in the patient. This is an enormous advance compared to known approaches, since known approaches either require an operator decision, which makes automation impossible, or have to perform an automated calibration without taking the external circumstances into account. A calibration is discarded completely only if analysis of the data indicates that at least one or some of the measurements included in the calibration in question may have been affected by external factors such as swallowing effort. Therefore, before starting a calibration, it is not possible to say with certainty whether this calibration is valid or whether it needs to be discarded.

[0087] Abnormal external conditions, such as a swallowing effort by the patient, may be detected by the esophageal balloon control system, for example, by monitoring the time course of the esophageal balloon pressure, particularly when a change in the pressure signal occurs at the end of the machine-prescribed inspiratory phase and / or the end of the machine-prescribed expiratory phase.

[0088] The ventilation controller may detect ventilation irregularities and, in accordance with such detection, provide appropriate control signals to the esophageal balloon control system when ventilation irregularities occur, such as swallowing efforts by the patient.

[0089] The calibration controller may be designed to interrupt the calibration when such a disturbance occurs and to continue only when it is determined that no further disturbances will occur. Such a determination may be made, for example, based on recorded esophageal balloon pressure and / or airway pressure. In this context, the ventilation controller may provide a corresponding control signal.

[0090] Furthermore, the calibration controller may be designed to calculate a quality index based on the data determined during the calibration procedure. The quality index may represent a weighted summary of the influence of various factors. In such an embodiment, the quality index may be used to decide whether or not to allow a change in ventilation parameters based on the esophageal balloon pressure data. A criterion related to the quality index may be a statistical scatter of the measurement data or an abnormal course of the esophageal balloon pressure / measurement fluid volume curve. As a measure of the quality index, the scatter of the measurements, for example expressed as a Gaussian standard deviation, may be used. Furthermore, specific rules may be defined to be included in the quality index. Such a rule may be, for example, that the quality index is reduced if a swallowing of the patient is detected during the calibration procedure. The quality index is reduced if the maximum value of the difference between the recorded esophageal balloon pressure at the end of inspiration and the recorded esophageal balloon pressure at the end of expiration at the measurement point is outside, in particular above, the linear region of the curve for the relationship between the esophageal balloon pressure and the amount of measurement fluid in the balloon probe. The quality index is decreased if the basal pressure, i.e., the esophageal balloon pressure at the end of the expiratory phase, does not remain the same over the course of successive measurements, or varies continuously but spikes. The quality index is decreased if the esophageal balloon pressure measured at higher values ​​of fluid volume in the balloon probe is lower than that measured at lower fluid volumes in the balloon probe.

[0091] Additionally, the calibration controller may be designed such that the esophageal balloon pressure should not exceed a predetermined maximum pressure. For example, it may be specified that the esophageal balloon pressure should not exceed twice the maximum airway pressure during ventilation. Once this pressure is reached, no further fluid is supplied to the balloon probe and / or fluid is evacuated from the balloon probe. This is intended to avoid overstretching of the esophageal tissue. This also helps prevent overstretching of the balloon probe, which may result in damage.

[0092] Finally, the calibration controller may control an ejection device to eject measurement fluid from the balloon probe as each measurement point is approached, such that the amount of measurement fluid in the balloon probe, starting from a starting value as described above, gradually decreases until it reaches or shortly before a predetermined minimum end-tidal esophageal balloon pressure, e.g. -5 hPa.

[0093] In a further embodiment, the calibration controller may comprise a mathematical model describing the respiratory system of the ventilated patient, which is designed to use the model and existing measurements for each measurement point, i.e. for a set amount of measurement fluid in the balloon probe between a start value and an end value, in order to determine, in particular by a respective regression method, relevant parameters related to the esophageal balloon pressure, such as airway resistance, distensibility of the lung tissue and / or distensibility of the thorax, and then derive, as an optimization task, an intended filling for the balloon probe. For example, the calibration controller may determine the optimal filling amount of measurement fluid in the balloon probe when the distensibility of the thorax is minimal, resulting from the regression procedure.

[0094] In a further embodiment, the above-mentioned esophageal balloon control system may comprise a fluid filling system having a filling controller designed to execute a fluid filling procedure for filling the balloon probe with a predetermined amount of measurement fluid after being controlled by the esophageal balloon control system and / or the ventilation controller. The predetermined amount of measurement fluid is intended to be a desired filling of the measurement fluid in the sense of a target fluid volume when the amount of measurement fluid introduced into the balloon probe is adjusted. The predetermined amount of measurement fluid is often a filling considered optimal and may be determined, for example, by a calibration procedure previously performed as described above.

[0095] The filling controller may be implemented as an independent component "in hardware". Alternatively, the filling controller may be implemented as a computer program product, i.e. by a corresponding software program running on a processor, in particular a microprocessor or microcontroller. In this case, the software may be stored on a suitable local or network accessible storage medium. The software includes instructions coded as a computer program, which, when loaded into the memory of the processor and translated into machine language, causes the processor to carry out the procedures described in more detail herein. Of course, a mixture of implementations in hardware and software is also conceivable. The microprocessor or microcomputer may be part of the control of the fluid filling system and may be assigned to the esophageal balloon control and / or the ventilation controller, depending on the design of the fluid filling system.

[0096] In order to ensure comparability and reproducibility of the filling state of the balloon probe achieved after the completion of the filling process, the filling controller may be designed to perform a draining procedure for removing the measurement fluid located in the balloon probe before the start of the fluid filling procedure for filling the balloon probe. The draining procedure may be most easily performed by allowing the pressurized measurement fluid to flow out of the balloon probe until the pressure is equal to the environment. However, the balloon probe can be emptied more easily and quickly using an active pumping device, whereby the measurement fluid is pumped out of the balloon probe until a predetermined final pressure is reached. In this case, the final pressure may be a negative pressure, i.e. a pressure lower than the ambient pressure.

[0097] In a further embodiment, the evacuation procedure for emptying the measurement fluid located in the balloon probe may include a procedure for setting a zero volume. The expression "zero volume" indicates a predefined filling of the measurement fluid in the esophageal balloon catheter, the measurement fluid essentially filling only the supply line to the balloon probe, while the balloon probe itself is still fully folded. This zero volume serves as a reproducible starting point for each filling step. This zero volume may be related to a specific pressure, for example the ambient pressure.

[0098] The procedure for setting the zero volume may include, for example, the steps of (i) withdrawing the measurement fluid from the balloon probe until a first predetermined negative pressure is reached in the balloon probe, (ii) introducing the measurement fluid into the balloon probe until a second predetermined negative pressure is reached in the balloon probe, the second predetermined negative pressure being greater than the first predetermined negative pressure, and (iii) introducing a predetermined volume of the measurement fluid into the balloon probe. In particular, the balloon should be fully collapsed during both the first and second negative pressures.

[0099] If the "dead volume" associated with a particular esophageal balloon catheter is known, a zero volume can also be provided by first largely evacuating the esophageal balloon catheter, i.e., pumping it to the lowest possible negative pressure, and then, starting from the state reached, introducing a predetermined amount of measuring fluid into the esophageal balloon catheter, whereby the predetermined amount of measuring fluid corresponds to the dead volume multiplied by the reference pressure (e.g., ambient pressure) at zero volume. The dead volume depends on the specific characteristics (e.g., tube length) of the particular esophageal balloon catheter, and therefore must typically be determined experimentally for the particular esophageal balloon catheter.

[0100] In a further embodiment, the filling controller may be designed to execute, after the above-mentioned emptying procedure for removing the measurement fluid located in the balloon probe, a fluid filling procedure for introducing the measurement fluid into the balloon probe until a predetermined overpressure is reached in the balloon probe. The introduction of the measurement fluid up to the predetermined overpressure is then performed before the actual setting of a predetermined amount of the measurement fluid in the balloon probe. It is therefore an intermediate step between emptying the balloon probe and setting of a predetermined amount of the measurement fluid in the balloon probe.

[0101] After a predetermined overpressure is reached in the intermediate step, more measurement fluid can be removed from the balloon probe (either passively by letting it flow out, or actively by pumping it out) until a predetermined balloon pressure corresponding to a predetermined filling is reached.

[0102] In a further embodiment, the esophageal balloon control system may be designed to detect a baseline esophageal balloon pressure and control the filling controller to execute a fluid filling procedure to fill the balloon probe with a measurement fluid when the baseline esophageal balloon pressure drops by more than a predetermined amount compared to the baseline level.

[0103] The expression "reference esophageal balloon pressure" denotes a pressure or pressure difference that does not change over many successive ventilation cycles and thus can serve as a measure of changes in the filling state of the balloon probe. For this purpose, it is useful to use as the reference esophageal balloon pressure a value that does not reflect changes in the esophageal balloon pressure due to individual ventilation profiles during successive ventilation cycles. In other words, the reference esophageal balloon pressure should be a recorded esophageal balloon pressure that is not superimposed with ventilation profiles that reflect inhalation and exhalation events during ventilation. In practice, for example, to determine the reference esophageal balloon pressure, the esophageal balloon pressure at the end of the expiratory phase of successive ventilation cycles can be determined. Alternatively, the esophageal balloon pressure at the end of the inhalation phase of successive ventilation cycles may be defined as the reference esophageal balloon pressure.

[0104] The above-mentioned esophageal balloon control continuously monitors whether the once set filling state of the balloon probe (which may be determined, for example, by the above-mentioned calibration procedure) remains stable and reacts with a corresponding correction of the filling of the measurement fluid in the balloon probe when a change of the reference esophageal balloon pressure relative to a reference level of more than a predetermined value is detected. This makes it possible, in particular, to compensate for the loss of the measurement fluid in the balloon probe due to leakage, as long as the leakage rate and / or loss of the measurement fluid in the balloon probe remains within certain limits. For example, it is conceivable to estimate the leakage rate by monitoring the period during which the reference esophageal balloon pressure drops by more than a predetermined amount or by monitoring how much the reference esophageal balloon pressure has dropped after a predetermined period. If the amount of loss or leakage rate of the measurement fluid is known, the leakage is compensated by refilling the balloon probe with a preselected amount of measurement fluid, which results from multiplying the amount of loss or leakage rate by the period corresponding to the period. Alternatively, refilling of the measurement fluid may be performed by monitoring the increase in esophageal balloon pressure on introduction of the measurement fluid into the balloon probe and terminating refilling when a predetermined esophageal balloon pressure is reached.

[0105] The above-mentioned measures make it possible to monitor, or at least estimate, the leakage rate of the esophageal balloon catheter. Based on this monitoring, it is decided whether and, if so, what further measures are required, for example starting a refilling procedure, initiating deflation of the balloon probe, or a complete recalibration of the balloon probe. The latter is always appropriate when one must assume that the changes in the recorded esophageal balloon pressure are not due to leakage alone, but that, for example, changes in the position of the balloon catheter in the esophagus also play a role. In the presence of such other evidence, a complete recalibration of the esophageal balloon catheter or, possibly, an exchange of the balloon probe may be considered.

[0106] If the leakage rate is too high, the time interval between successive filling procedures becomes too short. A warning may be displayed to the operator that the esophageal balloon catheter with balloon probe needs to be recalibrated or replaced. Such a measure may be provided, for example, if the esophageal balloon pressure drops by a predetermined amount, for example, by 2 cmH2O or more within 5 minutes.

[0107] It is noted that the possibilities described herein for providing a fluid-filled system for an esophageal catheter with a balloon probe, as well as the various possible embodiments of such a fluid-filled system, make, in the applicant's opinion, an independent contribution to the state of the art that is worthy of protection. This contribution is to be seen in particular independently of the further features contained in claim 1 or described in more detail above. The applicant reserves the right to formulate independent claims directed to the fluid-filled system in the further course of the prosecution of the invention, or to pursue such claims in a divisional application, if appropriate.

[0108] In a further embodiment, the above-mentioned fluid volume monitoring system may comprise a fluid volume monitoring section designed to carry out a procedure for ascertaining a desired or operational volume of the measuring fluid in the balloon probe after it has been activated. The desired or operational volume of the measuring fluid in the balloon probe may in particular be the volume of the measuring fluid in the balloon probe at which the balloon probe delivers an optimal signal for detecting the esophageal balloon pressure, which for this purpose is filled into the balloon probe as an operational filling starting from an evacuated esophageal balloon catheter. This desired or operational volume of the measuring fluid may for example be obtained as a result of a calibration, as described above with reference to the calibration system for automatic adjustment of the operational filling of the balloon probe of an esophageal balloon catheter. The monitoring of the fluid volume in the balloon probe is intended in particular to determine whether the desired or operational filling state of the balloon probe, once set, remains stable or undergoes changes over time. If such changes are detected by the above-mentioned fluid volume monitoring system, they may be responded to by refilling the balloon probe with the measuring fluid or by activating a complete recalibration of the esophageal balloon catheter, in particular to set a new operational filling of the balloon probe.

[0109] The fluid volume monitoring may be implemented as an independent component "in hardware". Alternatively, the fluid volume monitoring may be implemented as a computer program product, i.e. by a corresponding software program running on a processor, in particular a microprocessor or microcontroller. In this case, the software may be stored on a suitable local or network accessible storage medium. The software has instructions coded as a computer program, which, when loaded into the memory of the processor and translated into a machine language, causes the processor to carry out the procedures described in more detail herein. Of course, a mixture of hardware and software implementations is also conceivable. The microprocessor or microcomputer may be part of the control of the fluid volume monitoring system and may be assigned to the esophageal balloon control and / or the ventilation controller, depending on the design of the fluid volume monitoring system.

[0110] In a further embodiment, the fluid volume monitoring system, after starting the procedure for checking the desired filling of the measurement fluid in the balloon probe, may gradually change the amount of measurement fluid present in the balloon probe and thus detect the esophageal balloon pressure at each amount of measurement fluid in the balloon probe set as a measurement point and assign it to each amount of measurement fluid in the balloon probe set as a measurement point. The expression "detecting the esophageal balloon pressure" in particular intends to detect the differential pressure between the pressure in the balloon probe detected at the end of the inspiration phase and the pressure detected at the end of the expiration phase.

[0111] The fluid volume monitoring system can function similarly to the calibration system in that in both systems, the differential pressure between the pressure in the balloon probe recorded at the end of the inspiration phase and the pressure recorded at the end of the expiration phase of the ventilation cycle is determined and used as the basis for the respective calibration (setting of normal filling of the balloon probe of the esophageal balloon catheter) or for monitoring the filling state of the balloon probe. However, the monitoring of the filling state by the fluid volume monitoring system described here differs from the calibration system described above mainly in that the number of measurement points provided for monitoring the filling state of the balloon probe is much smaller than the number of measurement points provided during calibration.

[0112] In particular, the fluid volume monitoring system may be adapted to, after initiating a procedure for verifying a desired or operational filling of the measurement fluid in the balloon probe, change the existing volume of the measurement fluid in the balloon probe to a first comparative volume of the measurement fluid set as a measurement point greater than the existing volume of the measurement fluid. Once the first comparative volume of the measurement fluid is set, a first comparative esophageal balloon pressure is recorded, such that a first (upper) comparative measurement value pair results from the first comparative volume of the measurement fluid in the balloon probe and the associated first comparative esophageal balloon pressure.

[0113] Furthermore, the fluid volume monitoring system may be adapted to change the existing volume of the measurement fluid in the balloon probe to a second comparative volume of the measurement fluid set as a measurement point smaller than the existing volume of the measurement fluid after initiating the procedure for verifying the desired filling of the measurement fluid in the balloon probe, for which a second esophageal balloon pressure is recorded, such that a second comparative measurement value pair results from the second comparative volume of the measurement fluid in the balloon probe and the associated second comparative esophageal balloon pressure.

[0114] Overall, there are three pairs of measurement values ​​for the current filling of the balloon probe with measurement fluid: a pair of actual measurement values ​​assigned to the current filling from the amount of measurement fluid already in the balloon probe and the existing esophageal balloon pressure, a pair of first comparative measurement values ​​each assigned to a larger amount of measurement fluid in the balloon probe, and a pair of second comparative measurement values ​​each assigned to a smaller amount of measurement fluid in the balloon probe.

[0115] If desired, multiple pairs of first comparison measurements and multiple pairs of second comparison measurements may be generated and used as a basis for verifying a desired fill of measurement fluid in the balloon probe.

[0116] It should be noted that in the procedure for verifying the desired or operational filling of the measurement fluid in the balloon probe, the order in which the individual comparative measurement value pairs are determined may also be selected differently. In particular, in a first step, the amount of measurement fluid present in the balloon probe may be reduced to a second comparative amount of measurement fluid in order to obtain a second comparative measurement value pair related to a smaller amount of measurement fluid in the balloon probe. Only afterwards, in a second step, the amount of measurement fluid present in the balloon probe may be increased to a first comparative amount of measurement fluid in order to obtain a first comparative measurement value pair assigned to a larger amount of measurement fluid in the balloon probe.

[0117] In one embodiment, when the esophageal balloon pressure recorded in the first comparison measurement pair and the esophageal balloon pressure recorded in the second comparison measurement pair are within a predetermined range around the esophageal balloon pressure associated with the actual measurement pair (i.e., the esophageal balloon pressure associated with the existing amount of measurement fluid in the balloon probe), the fluid volume monitoring system may determine that the existing amount of measurement fluid in the balloon probe corresponds to a desired or operating amount of measurement fluid in the balloon probe.

[0118] The expression "detected esophageal balloon pressure" in particular denotes the differential pressure between the detected esophageal balloon pressure at the end of the inspiration phase and the detected esophageal balloon pressure at the end of the expiration phase of the ventilation cycle. This differential pressure is maximum at the desired filling of the measurement fluid in the balloon probe (i.e. at the time of the actual measurement pair). If the fluid volume monitoring system determines during the verification procedure that this differential pressure increases by more than a predefined value when the existing amount of measurement fluid in the balloon probe is changed (i.e. increased or decreased), this means that the desired or operational filling of the measurement fluid in the balloon probe is not in the actual measurement pair, but the differential pressure is changing in the direction of increasing. In this case, measures can be taken. These measures may depend on how much the differential pressure recorded in the first or second comparison measurement pair differs from the differential pressure assigned to the actual measurement pair.

[0119] For example, the fluid volume monitoring system may determine that the existing volume of measurement fluid in the balloon probe corresponds to the desired volume or operating volume of measurement fluid in the balloon probe when a first gradient defined by the esophageal balloon pressure recorded in a first comparison measurement pair (i.e., the first volume of measurement fluid set as the comparison measurement point) and the esophageal balloon pressure recorded in the actual measurement pair (i.e., the existing volume of measurement fluid in the balloon probe), and a second gradient defined by the esophageal balloon pressure recorded in a second comparison measurement pair (i.e., the second volume of measurement fluid set as the comparison measurement point) and the esophageal balloon pressure recorded in the actual measurement pair, do not exceed a first predetermined threshold, at least with respect to that volume.

[0120] The gradient may be defined, for example, as the difference between the esophageal balloon pressure recorded in the first or second comparative measurement pair and the esophageal balloon pressure recorded in the actual measurement pair, based on the difference between the amount of measurement fluid in the balloon probe set in the first or second comparative measurement pair and the amount of measurement fluid in the balloon probe set in the actual measurement pair, respectively. If necessary, the gradient may be related to a reference value (e.g. the esophageal balloon pressure measured for an existing amount of measurement fluid in the balloon probe). Alternatively, the ratio of these values ​​may be used as the gradient.

[0121] The slope defined as above is less than zero for both the first and the second comparison measurement pair if the measurement fluid volume in the balloon probe in the actual measurement pair, i.e. the existing measurement fluid volume in the balloon probe, corresponds to the desired or operational measurement fluid volume at which the end-inspiration and end-expiration pressure differences are at their maximum. If the slope for at least one of the first and the second comparison measurement pair is greater than zero, this value is in any case less than a predetermined first threshold value for all measurement pairs. The predetermined first threshold value may define a pressure difference range within which changes in the pressure difference are considered to be insignificant.

[0122] If both gradients thus detected are below a first predefined threshold value, it can be assumed that the existing amount of measuring fluid in the balloon probe represents the desired filling or is at least within a range around the existing amount of measuring fluid in the balloon probe defined by the amount of measuring fluid set for the first or second comparison measurement pair. In this case, no manipulation is required. In particular, the existing amount of measuring fluid in the balloon probe may be used as a desired or operating amount of measuring fluid in the balloon probe. The first predefined threshold value may, for example, be zero or a value slightly greater than zero.

[0123] In a further embodiment, the fluid filling system may be designed to activate or control the above-mentioned filling controller to execute a procedure for filling the balloon probe with a predetermined amount of measurement fluid when the fluid volume monitoring system determines that at least one of the first slope and the second slope is greater than a first threshold value.

[0124] In this case, in particular, the fluid volume monitoring system causes the fill controller to execute a fluid filling procedure for filling the balloon probe to set a new predetermined filling for the balloon probe, which is changed relative to the existing amount of measurement fluid in the balloon probe in the direction of the amount of measurement fluid in the balloon probe from the first and second comparison measurement pair from which the greater gradient was determined, and thus a new desired or operational filling of the balloon probe is determined and set for future ventilations.

[0125] For example, the new desired or operational filling of the balloon probe may correspond to the amount of measurement fluid in the balloon probe assigned to the one of the first and second comparison measurement pairs for which a larger gradient was determined.

[0126] Further, the calibration system may be designed such that when the fluid volume monitoring system determines that at least one of the first slope and the second slope is greater than a second threshold that is greater than the first threshold, the calibration system activates or controls the calibration controller described above to perform a calibration procedure to reset a desired or operational filling of the balloon probe with the measurement fluid.

[0127] If the esophageal balloon pressure detected by the fluid volume monitoring system is too far apart, then the conditions to which the balloon probe is exposed have changed significantly and a new calibration is indicated.

[0128] In a further embodiment, the esophageal balloon control system may be designed to control the fluid volume monitoring in response to a change in a ventilation parameter in order to execute a procedure for checking a predetermined filling of the measurement fluid in the balloon probe. In this way, after changing a ventilation parameter, for example PEEP, maximum airway pressure, tidal volume or ventilation frequency, it may be checked whether this change in ventilation conditions or ventilation mode affects the desired or operational filling of the balloon probe of the esophageal balloon catheter. If such an effect is detected, the filling may be immediately corrected or a complete new calibration of the esophageal balloon catheter may be performed. Ventilation may continue in an automated manner without any manual intervention by the operator.

[0129] Nevertheless, the information provided by the esophageal balloon catheter, in particular the information regarding the pressure in the pleural cavity, always remains as accurate as possible.

[0130] The possibility of providing a fluid volume monitoring system for an esophageal catheter with a balloon probe as described herein, as well as the various possible embodiments of such a fluid volume monitoring system, represents an independent contribution to the state of the art worthy of protection. In particular, this contribution should be seen independently of the features contained in claim 1, or the further features described in more detail above. The applicant reserves the right in the further course of the prosecution of the invention to formulate independent claims directed to the fluid filling system, or, where appropriate, to pursue such claims in a divisional application.

[0131] The invention also relates to a mechanical ventilation device comprising a device for automatic setting of ventilation parameters predetermined by the ventilator, in particular the pressure, in particular the positive end-expiratory pressure (PEEP) and / or the maximum airway pressure (Paw_max), and / or a device for automatic display of information regarding the artificial ventilation according to one of the above mentioned embodiments.

[0132] In another aspect, the invention relates to an esophageal balloon control system for an esophageal balloon catheter insertable into a patient's esophagus with a balloon probe for determining the esophageal balloon pressure. Such an esophageal balloon control system is provided and designed in particular to be used in a device for automatically setting predetermined ventilation parameters, in particular pressures, in particular positive end-expiratory pressure (PEEP) and / or maximum airway pressure (Paw_max), by a ventilation device according to one of the above-mentioned embodiments, and / or for automatically displaying information regarding mechanical ventilation.

[0133] Such an esophageal balloon control system therefore comprises a device, in particular a sensor, for detecting the esophageal balloon pressure and transferring the detected esophageal balloon pressure to a pressure detection system for determining the transpulmonary pressure, in particular the transpulmonary pressure at the end of the expiratory phase and / or the transpulmonary pressure at the end of the inhalation phase based on the detected esophageal balloon pressure. The esophageal balloon control system is designed for automatically monitoring and / or regulating the proper filling of a balloon probe of an esophageal balloon catheter in vivo and further for bidirectional interaction with a ventilation controller of a ventilation device.

[0134] Such an esophageal balloon control system may be implemented as a stand-alone component "in hardware". Alternatively, such an esophageal balloon control system may also be realized as a computer program product, i.e. by a corresponding software program executed on a processor, in particular a microprocessor or microcontroller. In this case, the software is stored on a suitable local or network accessible storage medium. The software includes instructions coded as a computer program, which, when loaded into the memory of the processor and translated into a machine language, causes the processor to execute the procedures described in more detail herein. Of course, a mixed form of implementation in hardware and in software is also conceivable. The microprocessor or microcomputer may belong to the control system of the esophageal balloon catheter with balloon probe and / or may be assigned to the ventilation control system of the device for mechanical ventilation, depending on the design of the esophageal balloon catheter.

[0135] In particular, the esophageal balloon control system may be designed to operate according to control commands provided by a ventilation controller of the ventilator.

[0136] The esophageal balloon control system may further be configured to transmit a predetermined esophageal balloon control signal to the ventilation controller. This means that the ventilation controller is not only designed to receive signals representative of the esophageal balloon pressure and / or the transpulmonary pressure from the esophageal balloon control system, but also to receive control signals from the esophageal balloon control system. Furthermore, the ventilation controller may further be designed for automatic control of the esophageal balloon control system, at least with regard to initiating and / or executing certain functions and / or procedures of the esophageal balloon control system. In this case, the esophageal balloon control system may have at least one or a combination of some of the features mentioned with reference to the above embodiments, in particular, as long as these features are suitable for characterizing the esophageal balloon control system.

[0137] According to a further aspect, the invention relates to an esophageal balloon catheter for determining the esophageal balloon pressure in vivo after insertion into a patient's esophagus. Such an esophageal balloon catheter is intended and designed in particular to be used in a device for automatic setting of predetermined ventilation parameters, in particular pressure, in particular positive end-expiratory pressure (PEEP) and / or maximum airway pressure (Paw_max), by a ventilation device and / or for automatic display of information regarding mechanical ventilation according to one of the above embodiments. The esophageal catheter comprises an esophageal balloon catheter, which includes a balloon probe for determining the esophageal balloon pressure and an esophageal balloon control system of the above type and is insertable into the patient's esophagus.

[0138] The esophageal balloon control system is configured to provide a signal representative of the sensed esophageal balloon pressure to the ventilation controller, and the ventilation controller is therefore configured to receive such a signal from the esophageal balloon control system.

[0139] According to the invention, the ventilation controller is also designed for automatic control of the esophageal balloon control system. In this sense, the ventilation controller is designed for bidirectional interaction with the esophageal balloon control system. The ventilation controller can control the esophageal balloon control system to initiate a given procedure. Additionally or alternatively, the ventilation controller may control the sequence of a given procedure in the esophageal balloon control system. In this way, an optimal interaction between the two control systems, the ventilation control system and the esophageal balloon control system, may be achieved, so that the procedures performed by the two systems are coordinated and synchronized.

[0140] Thus, according to a further aspect, the invention also relates to a ventilation controller for an apparatus for automatically setting ventilation parameters specified by the ventilator, in particular the pressure, in particular the positive end-expiratory pressure (PEEP) and / or the maximum airway pressure (Paw_max), and / or for automatically displaying information on mechanical ventilation, in particular according to one of the above embodiments. The ventilation controller is designed in particular to adjust the ventilation parameters specified by the ventilator on the basis of the transpulmonary pressure determined by an esophageal balloon catheter.

[0141] The ventilation controller may have a pressure detection system for determining the transpulmonary pressure, in particular the transpulmonary pressure at the end of the expiratory phase and / or the transpulmonary pressure at the end of the inhalation phase, based on an esophageal balloon catheter insertable into the patient's esophagus with a balloon probe for determining the esophageal balloon pressure.

[0142] The ventilation controller may be designed for bidirectional interaction with the esophageal balloon control system such that the ventilation controller controls the esophageal balloon control system in particular according to pressure values ​​provided by the pressure detection system.

[0143] The ventilation controller may be configured to set / control / adjust predetermined ventilation parameters and / or ventilation modes according to an esophageal balloon control signal provided by the esophageal balloon control system.

[0144] It will be appreciated that the ventilation control may have one or a combination of features, in particular those ventilation control features described with reference to the above embodiments.

[0145] This particularly relates to a pressure sensing device which will be described in more detail with reference to other embodiments.

[0146] According to a further aspect, the present invention further relates to a ventilation device comprising the above ventilation controller.

[0147] According to further aspects, the invention further relates to a method for the automatic setting of certain ventilation parameters by a ventilator, in particular a positive pressure, in particular a positive end-expiratory pressure (PEEP) and / or a maximum airway pressure (Paw_max), and / or for the automatic display of information on mechanical ventilation, in particular the transpulmonary pressure (Ptp), said method comprising the following steps: - determining the transpulmonary pressure, in particular the transpulmonary pressure at the end of the expiratory phase and / or the transpulmonary pressure at the end of the inhalation phase, on the basis of an esophageal balloon catheter insertable into the esophagus with a balloon probe for determining the esophageal balloon pressure by means of a pressure detection system, - automatically monitoring and / or automatically adjusting in vivo the proper filling of the balloon probe of the esophageal balloon catheter by an esophageal balloon control system; and - setting ventilation parameters specified by the ventilation device and / or displaying information regarding mechanical ventilation based on the transpulmonary pressure determined by the pressure determination system by the ventilation controller.

[0148] The method according to the invention provides that the ventilation controller and the esophageal balloon control system interact with each other bidirectionally, which in particular means that the ventilation controller is also designed for automatic control of the esophageal balloon control system and / or the esophageal balloon control system is also designed for automatic control of the ventilation controller.

[0149] For the purpose of determining the transpulmonary pressure, a pressure detection system may be provided which is assigned to the ventilation controller of the esophageal balloon catheter and / or esophageal balloon control system, including a balloon probe inserted into the esophagus to determine the esophageal balloon pressure.

[0150] In order to avoid repetition, for further embodiments of the method according to the invention reference is made to the more detailed description of the preceding embodiments, which also apply mutatis mutandis to the methods described herein. [Brief description of the drawings]

[0151] [Figure 1] FIG. 1 shows highly schematic, in block diagram form, the basic elements of a ventilation device according to one embodiment of the device according to the invention, including the intubated trachea and thorax of a patient during ventilation. [Diagram 2] FIG. 1 shows the time courses of airway inlet pressure Paw (top), esophageal balloon pressure Peso (middle), and the difference between the two pressures, Paw-Peso, during successive respiratory cycles during mechanical ventilation including an occlusion maneuver. [Diagram 3] 1 is a flow chart illustrating a procedure for in vivo calibration of an esophageal balloon catheter according to an embodiment of the present invention. [Figure 4] 1 is a diagram illustrating a schematic diagram of the amount of measurement fluid set in a balloon probe of an esophageal balloon catheter and the detected pressure in the balloon probe of the esophageal balloon catheter during calibration according to an embodiment of the present invention. FIG. [Diagram 5] Partial images a) and b) show diagrammatically the pressures detected in the balloon probe at the end of the inhalation phase, the pressures detected in the balloon probe at the end of the exhalation phase (partial image a) and the resulting differential pressure between the pressures in the balloon probe at the end of the inhalation phase and the pressures in the balloon probe at the end of the exhalation phase (partial image b) for each set amount of measurement fluid in the balloon probe during a measurement cycle. [Figure 6] 1 is a flow chart illustrating a process for in vivo monitoring of fluid within an esophageal balloon catheter according to an embodiment of the present invention. [Figure 7] 1 is a flow chart illustrating a filling procedure for an esophageal balloon catheter according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0152] Further embodiments of the invention are described in detail below with reference to the drawings.

[0153] 1 shows in a highly schematic manner in the form of a block diagram the basic elements of a ventilator 10 according to an embodiment of the device according to the invention, including the intubated trachea 12 and thorax of a ventilated patient. According to one embodiment of the invention, the ventilator 10 comprises a device 15 for automatically displaying information relating to the mechanical ventilation based on the settings of ventilation parameters pre-set by the ventilator 10 and / or on the esophageal balloon pressure.

[0154] As shown in Fig. 1, the ventilator 10 is intubated into the trachea 12 of a patient undergoing ventilation. In Fig. 1, the patient's trachea 12, as well as the lungs 28, 30, heart 32, esophagus 34 and thoracic wall 42 are shown very diagrammatically. A tube 14 of the ventilator 10 is inserted a short distance into the trachea 12, usually from the patient's mouth (not shown), to supply breathing gas to the airway. Exhaled air is also discharged through the tube 14, which at its upstream or distal end is bifurcated into a first end 16 and a second end 22. The first end 16 is connected via an airway inlet valve 18 to an airway inlet connection of a breathing gas system 200 of the ventilator 10. During the inspiration phase, breathing gas for ventilation is supplied to the lungs via the airway inlet port under an overpressure known as the inspiratory pressure Plnsp. Thus, during the inspiration phase, in the open position of the airway inlet valve 18, the airway inlet connection receives an inspiration pressure Plnsp generated by the breathing gas system 200 according to a control command from the ventilation controller 180. The second end 22 is connected to the airway outlet port of the breathing gas system 200 of the ventilator 10 via the airway outlet valve 24. In the open position of the airway outlet valve 24, the airway receives an expiration pressure Pexp. Both the inspiration pressure Plnsp and the expiration pressure Pexp are detected by a pressure determination system 300 of the ventilator 10.

[0155] The pressure determination system 300 comprises a sensor system designed to determine the esophageal balloon pressure, comprising an esophageal balloon catheter 45 with a balloon probe 46 insertable in the esophagus 34, and at least one device for detecting the pressure in the balloon probe 46 in vivo. The pressure determination system 300 comprises a sensor system designed in particular to determine the alveolar pressure Palv and to determine the transpulmonary pressure Ptp based on the difference between the alveolar pressure Palv and the esophageal balloon pressure Peso. The sensor system for determining the alveolar pressure Palv can be designed to determine the airway resistance R and may comprise a sensor for detecting the gas flow in the airway, in particular at the end of the expiratory phase and / or at the end of the inhalation phase. The sensor can determine the alveolar pressure Palv based on the respiratory flow rate and the airway resistance R. The sensor system for detecting the alveolar pressure Palv may comprise an airway pressure sensor for detecting the inlet airway pressure, for example arranged at the beginning of the tube of the ventilation device 10 or associated with the airway inlet valve 18 of the ventilation device 10.

[0156] The inspiratory pressure Plnsp is generated by the ventilator 10, in particular the respiratory gas system 200, according to a control command from the ventilation controller 180, so that the respiratory gas to be inhaled during the inhalation phase flows according to a predetermined temporal pattern in the direction of the patient's lungs 28, 30, as indicated by the arrow 20 in FIG. 1. Exhalation may occur by passively allowing the respiratory gas to flow out of the lungs 28, 30 to the airway outlet port during the exhalation phase, as indicated by the arrow 26. The expiratory pressure Pexp is then determined during the exhalation phase based on the patient's physiological characteristics and the maximum inspiratory pressure that prevails at the beginning of the exhalation phase. If necessary, exhalation is also supported or completely generated by the ventilator 10, in particular the respiratory gas system 200, according to a control command from the ventilation controller 180, so that a course of the respiratory gas flow and / or the expiratory pressure Pexp occurs during the expiratory phase that corresponds to a predetermined temporal pattern.

[0157] Normally, during the inspiration phase, the airway inlet valve 18 remains open and the airway outlet valve 24 remains closed. The airway inlet is subjected to an inspiration pressure Plnsp. During the expiration phase, the airway inlet valve 18 is closed and the airway outlet valve 24 is open. The airway is then subjected to an expiration pressure Pexp.

[0158] The breathing gas may include ambient air, but typically contains a percentage of pure oxygen that is higher than the oxygen content of ambient air. The breathing gas may also be humidified.

[0159] The flow of respiratory gas at the airway inlet during the inspiration phase is determined using an airway inlet flow sensor 36. The airway inlet flow sensor 36 is based on detecting a pressure difference dP between an inlet volume 38 and an outlet volume 40 connected to the inlet volume 38, and determines the respiratory gas mass flow at the airway inlet. At the same time, the value of the airway inlet pressure Paw can be easily derived from the pressure signal in the outlet volume 40. The pressure difference dP between the inlet volume 38 and the outlet volume 40 as well as the airway inlet pressure Paw are also detected by a pressure determination system 300 of the ventilator 10.

[0160] The airway inlet flow sensor 36 is also used to detect the respiratory gas flow rate F at the airway outlet during the expiratory phase and the airway outlet pressure Paw. In this regard, reference is made to the previous explanation, provided that the role of the inlet and outlet volumes swaps as a result of the reversal of the respiratory gas flow direction, i.e. the volume indicated at 40 is the inlet volume and the volume indicated at 38 is the outlet volume.

[0161] The control of the inhaled gas during the inhalation phase and the exhaled gas during the exhalation phase is performed by the ventilation controller 180 of the ventilator 10. The ventilation controller 180 communicates with the respiratory gas system 200 to control / adjust the supply of the inhalation pressure Plnsp and / or with the exhalation pressure Pexp to the airways. If necessary, the ventilation controller 180 may receive signals from the respiratory gas system 200 such that the communication connection between the ventilation controller 180 and the respiratory gas system 200 is bidirectional. The ventilation controller 180 communicates with the pressure determination system 300 to receive signals representative of variables related to ventilation, in particular signals from pressure sensors. For example, the ventilation controller 180 may receive signals from the pressure determination system 300 related to at least one of the following variables: inhalation pressure Plnsp, exhalation pressure Pexp, respiratory gas flow at the airway inlet F, airway pressure Paw, and esophageal balloon pressure Peso, which will be described in more detail below. If desired, the ventilation controller 180 can also send signals, particularly control signals, to the pressure determination system 300 such that the communication connection between the ventilation controller 180 and the pressure detection system is bidirectional.

[0162] The ventilation controller 180 is only shown diagrammatically as block 180 in FIG. 1 and will only be described in greater detail herein insofar as its functionality is necessary for an understanding of the invention.

[0163] With regard to further aspects of the ventilation controller 180, reference is made to known ventilation devices, in particular to ventilation devices that include control of ventilation in different ventilation configurations or modes, for example to known ventilation devices that include ventilation modes in which ventilation is controlled by a closed control loop, such as the ASV ventilation mode ("adaptive assisted ventilation") and the INTELLiVENT-ASV ventilation mode in Applicant's ventilator.

[0164] This is equally true for the other subsystems shown in FIG. 1, the breathing gas system 200, the pressure determination system 300, and the esophageal balloon control system 400.

[0165] 1 as separate systems should be understood as merely an example and has been chosen to better represent the functionality assigned to each system, and although not explicitly stated below, it should be understood that in an actually realized embodiment some or even all of these systems may be combined to form an overall system with their respective functionality.

[0166] Any form of known ventilation method or mode may be used in combination with the present invention, for example pressure-controlled ventilation, volume-controlled ventilation, or a ventilation mode in which pressure-controlled and volume-controlled aspects are combined. In addition to purely mechanically controlled forms of ventilation, in which the time course of the inspiratory pressure Plnsp, and possibly the time course of the expiratory pressure Pexp, are determined by the ventilator 10, and in particular by the ventilation controller 180, forms of ventilation are also conceivable in which the patient's spontaneous breathing efforts can support mechanical ventilation, or in which mechanical ventilation acts to support the patient's spontaneous breathing efforts. In such forms of ventilation, the time course of the inspiratory pressure Plnsp or expiratory pressure Pexp, and often the position of the airway inlet valve 18 or outlet valve 24, are not predetermined solely by the ventilator 10, but the ventilation controller 180 is configured in such a way that the patient's spontaneous breathing efforts can affect variables such as the time course of the inspiratory pressure Plnsp and / or expiratory pressure Pexp, the position of the airway inlet valve 18 and / or outlet valve 24, etc.

[0167] In FIG. 1, the ventilation controller 180 is shown diagrammatically to comprise an adjustment unit 185 which, based on user settings and / or detection signals, selects one of a plurality of ventilation modes 190A, 190B, 190C, 190D as an active ventilation mode and, based on control signals provided by the active ventilation modes 190A, 190B, 190C, 190D, respectively, controls the respiratory gas system 200 to apply a respective inspiratory pressure Plnsp and / or a respective expiratory pressure Pexp to the airway.

[0168] The ventilation modes 190A, 190B, 190C and 190D have a unit for setting ventilation parameters (such as positive end-expiratory pressure PEEP or maximum airway pressure Paw_max), respectively indicated by reference numbers 192A, 192B, 192C and 192D in Fig. 1. The ventilation modes 190A, 190B, 190C and 190D also include a unit for automatic display of information and / or settings relating to ventilation, such as transpulmonary pressure Ptp, respectively indicated by reference numbers 194A, 194B, 194C and 194D in Fig. 1.

[0169] The adjustment unit 185 causes the setting of values ​​of ventilation parameters 192A, 192B, 192C, 192D determined by the active ventilation mode 190A, 190B, 190C, 190D or information and / or settings 194A, 194B, 194C, and 194D determined by the active ventilation mode to be displayed on a display, indicator, or other output device of the ventilator 10. The output device is not explicitly shown in FIG. 1. The adjustment unit 185 also switches between the different ventilation modes 190A, 190B, 190C, and 190D. The set ventilation parameters 192A, 192B, 192C, 192D and / or their parameter values, as well as the displayed information 194A, 194B, 194C, and 194D, change accordingly when switching between ventilation modes 190A, 190B, 190C, 190D.

[0170] In FIG. 1 an additional esophageal balloon catheter 45 with a balloon probe 46 for measuring the pressure in the esophagus (food pipe) 34, called esophageal balloon pressure or esophageal pressure, is shown diagrammatically. The balloon probe 46 has a balloon shape and is attached to a catheter tube 48 that can be inserted into the esophagus 34. FIG. 1 shows diagrammatically the esophageal balloon catheter 45 with the balloon probe 46 inserted in its measuring position in the esophagus 34 of a patient to be ventilated. In this measuring position, the esophageal balloon catheter 45 is designed to detect the esophageal balloon pressure Peso in the balloon probe 46, from which the transpulmonary pressure Ptp can be deduced. The balloon probe 46 abuts against the inner wall of the esophagus 34. The esophageal balloon pressure Peso in the balloon probe 46 provides, after appropriate calibration, the esophageal pressure acting on the esophagus 34 at the position of the balloon probe 46. If the patient is properly positioned, the esophageal pressure corresponds closely to the pressure Ppl in the pleural cavity. The balloon probe 46 for measuring esophageal pressure and the handling of this probe are described, for example, in Benditt J. Resp. Care 2005, 50:68-77 (Non-Patent Document 3).

[0171] The esophageal balloon catheter 45 is associated with an esophageal balloon control system 400 designed to monitor, calibrate and / or fill a balloon probe 46 of the esophageal balloon catheter 45 with a measuring fluid. The ventilator 10 and the esophageal balloon control system 400 are designed such that there is a two-way communication between the ventilation controller 180 and the esophageal balloon control system 400. This means that the ventilation controller 180 is also designed for automatic control of the esophageal balloon control system 400 and / or the esophageal balloon control system 400 is also designed for automatic control of the ventilation controller 180.

[0172] In Fig. 1, this bidirectional communication between the ventilation controller 180 and the esophageal balloon control system 400 is indicated by the arrows 150 and 160. Such a configuration is adapted to the form of ventilation in which ventilation is performed by a fully automatic ventilation mode, in particular in the case of ventilation by closed control loop, for example as used in adaptive assisted ventilation (ASV ventilation) developed by the applicant and in INTELLiVENT-ASV ventilation, also developed by the applicant. Such a form of ventilation is characterized by the fact that only a minimum of manual intervention is required by the operator, and the ventilator automatically sets or adjusts, with the help of a suitable closed control loop, ten important ventilation parameters, such as positive end-expiratory pressure PEEP or maximum airway pressure Paw_max, within a predefined value range.

[0173] The esophageal balloon control system 400 is also designed for communication, particularly bidirectional communication 140, 140', with the pressure determination system 300 so that the esophageal balloon control system 400 has access to the pressures Pinsp, Pexp, dP, Paw, and Peso determined by the pressure determination system 300.

[0174] The pressure prevailing in the alveoli of the lungs 28, 30, also called "alveolar pressure", is symbolized as Palv in Fig. 1. The alveolar pressure Palv depends on the airway entrance pressure Paw, the airway resistance R, and the flow of respiratory gas V into or out of the lungs. In the case of perfect pressure equalization between the airway entrance and the alveoli, the alveolar pressure Palv is equal to the airway entrance pressure Paw (Palv = Paw).

[0175] Such complete pressure equalization stops the flow of respiratory gas F. Pressure equalization may also be brought about by a brief airway occlusion maneuver, for example, in which the airway inlet valve 18 and the airway outlet valve 24 are closed simultaneously. The occlusion maneuver must last just long enough to stop the gas flow F in the airway, which is typically 1 to 5 seconds. In this condition, the alveolar pressure Palv can be determined by determining the airway inlet pressure Paw.

[0176] Between both physiological respiration and mechanical ventilation, the respiratory gas flow F is determined by the pressure difference Δp = Palv - Paw between the alveolar pressure Palv and the airway inlet pressure Paw.

[0177] In the case of purely physiological respiration, during inspiration due to the expansion of the chest 42, a negative pressure difference, i.e., a negative pressure, occurs between the alveolar pressure Palv and the airway inlet pressure Paw. This is related to the decrease in the pressure Ppl in the pleural cavity 44 formed between the chest 42 and the lungs 28, 30. Expiration occurs passively through the relaxation of the chest 42 and the elastic recovery of the lung tissue. Therefore, during physiological respiration, the pressure in the pleural cavity Ppl is always smaller than the alveolar pressure Palv (Ppl > Palv). Thus, the transpulmonary pressure Ptp = Palv - Ppl, defined as the difference between the alveolar pressure Palv and the pressure in the pleural cavity Ppl, is generally positive and becomes zero in the case of complete equal pressure.

[0178] During mechanical ventilation, the respiratory gas is pumped into the lungs under positive pressure. Therefore, during the process of mechanical ventilation, during the inspiratory phase, the airway inlet pressure Paw = Plnsp is greater than the alveolar pressure Palv, which is greater than the pressure in the pleural cavity Ppl. Paw > Palv > Ppl

[0179] From these pressure conditions, the transpulmonary pressure Ppl will be positive (Ppl > 0) during the process of inspiratory mechanical ventilation. During expiration, the airway inlet receives an airway pressure Pexp (Pexp < Palv) that is lower than the alveolar pressure Palv, and the respiratory gas flows out of the alveoli. In the case of a very low airway pressure Pexp, at the end of expiration, when very little gas remains in the lungs, the pressure in the pleural cavity Ppl may exceed the alveolar pressure Palv to such an extent that a part of the alveoli of the lungs collapses. In that case, the transpulmonary pressure Ptp is negative (Ptp < 0).

[0180] Undesirable and harmful collapse of the alveoli can be prevented by applying an additional positive pressure to the airway inlet during the expiratory phase. Then, there is a persistent airway positive pressure at the airway inlet, i.e., during the inspiratory phase and also during the expiratory phase. This airway positive pressure is called positive end-expiratory pressure PEEP.

[0181] Therefore, the transpulmonary pressure Ptp is a suitable value for setting PEEP. However, the transpulmonary pressure Ptp cannot be measured directly and, as mentioned above, cannot be determined from pressures measured periodically during mechanical ventilation.

[0182] In order to determine the transpulmonary pressure Ptp, information about the alveolar pressure Palv is needed in addition to the pressure in the pleural cavity Ppl. A method for determining the alveolar pressure Palv(t) at a particular time t is to measure the respiratory gas flow F(t), which can be done using the airway inlet flow sensor 36.

[0183] After measuring the respiratory gas flow F(t), the alveolar pressure at time t can be determined using the relationship Palv(t)=Paw(t)-R*V(t), where R represents the airway resistance. The airway resistance R is a variable that is essentially constant or changes relatively slowly for the same patient and can be determined by methods known in the state of the art, for example, Lotti IA et al. Intensive Care Med. 1995,21:406-413. Since the determination of the appropriate PEEP depends mainly on the transpulmonary pressure at the end of the expiratory phase Ptp_ee, in conjunction with the automatic adjustment of PEEP, the alveolar pressure Palv is preferably measured at the end of expiration according to the following formula: Ptp_ee=Palv_ee-Peso_ee=Paw_ee-R*V_ee-Peso_ee

[0184] PEEP should be set so that Ptp_ee always remains positive and does not fall significantly below zero.

[0185] Unfortunately, the described method for determining the alveolar pressure Palv, which can be very easily implemented in an automatic ventilator 10, allows only a relatively rough estimation of the appropriate PEEP. This is mainly due to the fact that the airway resistance R can only be estimated relatively imprecisely and is generally subject to certain trends over the course of treatment.

[0186] An alternative method for determining the alveolar pressure Palv is based on a short-term occlusion maneuver in which both the airway inlet valve 18 and the airway outlet valve 24 are kept closed simultaneously. In this occlusion state, an equalization of the pressure in the airway occurs. If such an occlusion maneuver is performed at the end of the expiratory phase, the pressure that develops in the airway after a sufficiently long occlusion will be a good approximation equal to the alveolar pressure Palv at the end of the expiratory phase. This pressure can then be easily measured using a pressure probe placed at the airway inlet to measure the airway pressure Paw. In FIG. 2, this situation is shown in the position indicated by reference number 50.

[0187] FIG. 2 shows the time course of the airway pressure Paw (FIG. 2(a)), the esophageal balloon pressure Peso measured by the balloon probe 46 (FIG. 2(b)), and the difference between the two pressures Paw-Peso during several consecutive respiratory cycles, during which an occlusion maneuver was also performed. In FIG. 2, the individual respiratory cycles can be clearly seen, with their respective inspiratory phases (high upward airway pressure Paw in FIG. 2(a)) and expiratory phases (downward airway pressure Paw).

[0188] The esophageal balloon pressure Peso follows the airway pressure Paw, but in a weakened form. The differential pressure Paw-Peso, shown in the lower curve (Fig. 2(c)), corresponds quite well to the transpulmonary pressure Ptp, if the flow of respiratory gas is slow enough and pressure equalization always occurs. In practice, however, this requirement is generally not met, due to the strong changes in respiratory gas flow, except at the places designated by reference numbers 50 and 52, where a short-term occlusion was performed at the end of the expiratory phase (reference number 50, from about 8 s to 12 s) or at the end of the inspiratory phase (reference number 52, from about 18.5 s to 24.5 s). In both cases, the occlusion lasted for about 4 seconds. In the selected example, this corresponds approximately to the duration of one respiratory cycle. In general, the occlusion should last long enough for a complete pressure equalization in the airways to occur and for the gas flow in the airways to stop.

[0189] At the end of the position marked 50 in the time profile (between approximately 11 and 12 seconds, for example in the last 200 ms of the occlusion), the pressure Paw-Peso shown in the third line of FIG. 2 approximates quite well to the transpulmonary pressure at the end of the expiratory phase Ptp_ee. To determine Ptp_ee, for example, Paw-Peso may be averaged over the mentioned period. At the end of the position marked 52 in the time profile (between approximately 21.5 and 22.5 seconds, for example in the last 200 ms of the occlusion), the pressure Paw-Peso shown in the third line approximates quite well to the transpulmonary pressure at the end of the inspiratory phase Ptp_ei. To determine Ptp_ei, for example, Paw-Peso may be averaged over the mentioned period. To determine Ptp_ei, for example, Paw-Peso may be averaged over the mentioned period.

[0190] The determination of the transpulmonary pressure Ptp using the above-mentioned occlusion maneuver is more accurate than the above-mentioned method using the airway resistance R. However, it is necessary to perform the occlusion maneuver at the end of the expiratory phase or at the end of the inhalation phase. This method therefore naturally interrupts the respiratory cycle, and the longer the duration of the occlusion is compared to the duration of the respiratory cycle, the more interrupted it becomes. Thus, essentially, the method interferes with the respiratory cycle, which becomes more noticeable if the duration of the occlusion is compared to the duration of the respiratory cycle. For this reason, it is advisable to proceed with the airway resistance method to check fairly frequently, for example after each breath or every n breaths (n>1), whether the set value of the PEEP and / or the set value of the maximum airway pressure are still within specifications or whether the resulting value of the transpulmonary pressure Ptp_ee is within a certain specification of the normalized transpulmonary pressure Ptp_ee_ideal.

[0191] If the examination reveals that this is not the case and therefore that new (higher or lower) values ​​for PEEP and / or maximum airway pressure should be set, then at the end of the expiratory phase, an occlusion maneuver is performed in the next respiratory cycle and a new value for PEEP is determined based on this occlusion, as described above. Alternatively, as described, the occlusion maneuver may be repeated every n respiratory cycles, with n>1, e.g., n=10, 50, or 100.

[0192] A prerequisite for the determination of the transpulmonary pressure Ptp using the esophageal balloon catheter 45 with the balloon probe 46 is that there is a fixed relationship between the transpulmonary pressure Ptp and the esophageal balloon pressure Peso detected in the balloon probe 46. Ideally, the esophageal balloon pressure Peso detected in the balloon probe 46 should approximately correspond to the pressure in the pleural cavity Ppl, so that the transpulmonary pressure Ptp is calculated from the difference between the airway pressure Paw and the esophageal balloon pressure Peso. However, in practice, it regularly occurs that the relationship between the esophageal balloon pressure Peso measured with the esophageal balloon catheter 45 with the balloon probe 46 introduced into the esophagus 34 and the pressure Ppl in the pleural cavity during ventilation changes. Such changes usually cannot be clearly attributed to a specific cause or event and often occur gradually.

[0193] For this reason, it is often advantageous to continuously monitor the esophageal balloon catheter 45, if necessary, in conjunction with filling or refilling the balloon probe 46 with measurement fluid, and possibly (re)calibrating the amount of measurement fluid in the balloon probe 46 of the esophageal balloon catheter 45, to be selected as intended.

[0194] However, the esophageal balloon catheters 45 currently used for mechanical ventilation in vivo are very sensitive and their use is complicated and time-consuming for the nursing staff. Therefore, the esophageal balloon catheters 45 are currently not particularly suitable for use in the course of ventilation of a patient, especially in the course of long-term ventilation, for continuous monitoring of the transpulmonary pressure Ptp during ventilation and, if necessary, for correcting inaccurate filling. In particular, doctors and nursing staff currently have very limited access to the measurement data provided by the esophageal balloon catheter during ventilation and thus actually available for monitoring and / or adjusting ventilation parameters during the current ventilation.

[0195] The present invention provides an apparatus and a method for improving the accuracy of pressure measurements provided by an esophageal balloon catheter 45 with a balloon probe 46 inserted into the esophagus 34. In particular, the apparatus according to the invention and the method according to the invention allow a more accurate reproduction of the pressure Ppl prevailing in the pleural cavity through the esophageal balloon catheter 45 and allow a faster response of the measurements to changing environmental conditions during continuous ventilation.

[0196] Thus, the invention allows a continuous and largely automated operation of the esophageal balloon catheter 45, which allows continuous monitoring of the settings and, if necessary, refilling or recharging the balloon probe 46 with measuring fluid, without the need to interrupt ventilation. It is also possible to calibrate or recalibrate the balloon probe 46 during ongoing ventilation and / or to determine the optimal filling amount of measuring fluid in the balloon probe 46 for measuring the transpulmonary pressure Ptp. This also applies when ventilation is performed using fully automatic ventilation modes, for example in the case of ventilation using a closed control loop, in particular in the case of "adaptive assisted ventilation" (ASV ventilation) developed by the applicant and INTELLiVENT-ASV ventilation, also developed by the applicant.

[0197] The esophageal balloon control system 400 is associated with the esophageal balloon catheter 45. The esophageal balloon control system 400 has the specific function of supplying a measurement fluid to the balloon probe 46 of the esophageal balloon catheter 45. Typically, air is used as the measurement fluid, but other fluids, particularly gases, can also be used.

[0198] In principle, after insertion into the esophagus 34 and placement of the balloon probe 46 in the esophagus 34, the balloon probe 46 is inserted into the esophagus 34 with a predetermined amount of measurement fluid V opt The balloon probe 46 is filled with the measuring fluid and dimensioned so that the pressure measured by the balloon probe 46 reacts as sensitively as possible to pressure changes in the pleural cavity 44 via the outer wall of the esophagus 34 on the balloon probe 46. For this purpose, the balloon probe 46 is placed in a position in the esophagus 34 and, if possible, is subjected to the pressure in the pleural cavity 44. At the same time, the balloon probe 46 is filled with enough measuring fluid so that it fits as evenly as possible against the inner wall of the esophagus 34. The pressure in the balloon probe 46 should not be so great that the wall of the esophagus 34 cannot expand outwardly under the pressure prevailing in the balloon probe 46. In order to set the appropriate or optimal filling of the balloon probe 46 with the measuring fluid, a calibration of the balloon probe is provided. The esophageal balloon control system 400 is designed to perform such a calibration chronologically. For this purpose, the esophageal balloon control system 400 includes a calibration controller 450.

[0199] The calibration controller 450 is configured to set a plurality of measurement points by gradually changing the liquid volume Vi (i=1, 2, 3, . . .) of the measurement fluid in the balloon probe 46. In this manner, for the amount Vi of the measurement fluid in the balloon probe 46 that is gradually set as a measurement point, the calibration controller 450 records the esophageal balloon pressure Pesoi and assigns this set amount Vi of the measurement fluid to the balloon probe 46. For this purpose, the pressure signal Pesoi detected by the balloon probe 46 is also transmitted to the calibration controller 450.

[0200] The esophageal balloon control system 400 also includes a pumping device 430 configured to introduce a measurement fluid into the balloon probe 46 and remove the measurement fluid from the balloon probe 46 after the balloon probe 46 is positioned in the esophagus 34. The pumping device 430 has a pump 425 and a valve 420 disposed in the delivery line 66 for measuring fluid in fluid communication with the balloon probe 46. If the measurement fluid in the balloon probe 46 is under excessive pressure, the measurement fluid may be removed from the balloon probe 46 without using an actual pump 425 by opening the valve 420.

[0201] The esophageal balloon control system 400 further comprises a flow sensor 410, in particular a mass flow sensor 410 designed to determine the amount of measurement fluid introduced into the balloon probe 46 and / or the amount of measurement fluid removed from the balloon probe 46. The amount of measurement fluid introduced into or removed from the balloon probe 46 can be determined, for example, by integrating the flow rate measured by the flow sensor 410 over a period between a start time and an end time. The flow sensor 410 can be designed, for example, to determine the mass flow rate of the measurement fluid based on a differential pressure. Such a flow sensor 410 can also be used to detect the esophageal balloon pressure Peso in the balloon probe 46.

[0202] The calibration controller 450 can be implemented as an independent component "in hardware". Alternatively, the calibration controller 450 can be implemented as a computer program product, i.e. by a corresponding software program running on a processor, in particular a microprocessor or microcontroller. In this case, the software can be stored on a suitable local or network accessible storage medium. The software includes instructions coded as a computer program, which, when loaded into the memory of the processor and translated into a machine language, causes the processor to carry out the procedures described in more detail herein. Of course, a mixture of hardware and software implementations is also conceivable. A microprocessor or microcontroller may be associated with the control of the esophageal balloon control system 400, in particular may be part of the control of the esophageal balloon control system 400.

[0203] FIG. 3 illustrates in flow chart form a procedure for in vivo calibration of an esophageal balloon catheter 45 according to one embodiment of the present invention.

[0204] FIG. 4 shows a measurement fluid volume V of a balloon probe 46 of an esophageal balloon catheter 45 set during calibration according to an embodiment of the present invention. b 13 shows a schematic diagram of the change over time in the esophageal balloon pressure Peso detected by the balloon probe 46 of the esophageal balloon catheter 45.

[0205] The calibration controller 450 adjusts the measurement fluid V in the balloon probe 46 in at least two steps to approach each measurement point S1, S2, M1, M2, . . . , M7, E1, E2, E3, starting from a starting value S2 until a final value E3 is reached. b The amount of

[0206] The measuring fluid may in particular be air or another fluid, in particular another gas.

[0207] The calibration procedure 100, shown in Figure 3, begins at step 102. First, at step 104, measurement fluid is pumped through the balloon probe 46 until a predetermined initial pressure is created within the balloon probe 46. The state reached at step 104 is designated "N" in Figure 4.

[0208] Thereafter, in step 106, measurement fluid is again pumped into the balloon probe 46 until the pressure in the balloon probe 46 reaches a predetermined positive pressure above the expected measurement range for the measurement cycle. The state of step 104 is designated "D1" in FIG.

[0209] All other measurement points approached in steps 108-130 below are designated in FIG. 4 as S1, S2, M1-M7, E1, E2, E3.

[0210] In the state set in step 106, the balloon probe 46 is significantly overstretched. This can be seen in Fig. 4 from the fact that the value of the esophageal pressure Peso detected at the balloon probe 46 is significantly higher than all other measurement points S1, S2, M1-M7, E1, E2, and E3.

[0211] In Figures 4 and 5, the upper limit of the measurement range is designated O, and in Figures 4 and 5, the lower limit of the measurement range is designated U. In the calibration procedure shown in Figures 4 and 5, it can be seen that the lower limit U of the measurement range is at measurement point M7, and the upper limit O of the measurement range is at measurement point M1. For the upper limit O and the lower limit U, the corresponding volume V of the measurement fluid in the balloon probe 46 is b was selected as the reference value. Thus, O indicates the amount of measurement fluid in the balloon probe 46 at the measurement point M1, which corresponds to the upper limit of the measurement range. U indicates the amount of measurement fluid in the balloon probe 46 at the measurement point M7, which corresponds to the lower limit of the measurement range.

[0212] Starting from step 106, in step 108, a predetermined amount of measurement fluid is pumped out of the balloon probe 46. This sets the amount of measurement fluid in the balloon probe 46 at which an esophageal balloon pressure Peso is detected that is slightly above the esophageal pressure expected within the measurement range (see measurement points M1-M7). This state is shown as "S1" in Figures 4 and 5. Alternatively, measurement fluid can be pumped out of the balloon probe 46 until a predetermined value of the esophageal balloon pressure Peso is detected that is slightly higher than the esophageal balloon pressure Peso expected within the measurement range (see measurement points M1-M7).

[0213] During the "S1" state, the esophageal balloon pressure Peso is detected in the balloon probe 46 over multiple respiratory cycles. As can be seen from Figure 4, the esophageal balloon pressure Peso reflects the individual respiratory cycles, but only to a very small extent, which indicates the low sensitivity of the balloon probe 46.

[0214] Starting at step 108, a predetermined amount of measurement fluid is pumped from the balloon probe 46 in step 110 until a state designated "S2" in Figures 4 and 5 is reached. In step 110, the same procedure is repeated for state "S2" as described with respect to step 108. Again, only a few noticeable respiratory cycles can be seen and therefore the sensitivity of the balloon probe 46 is low.

[0215] After completion of step 110, a predetermined amount of measurement fluid is again pumped from balloon probe 46 in step 112 until the state indicated as "M1" in Figures 4 and 5 is reached. In step 112, the same procedure as described in connection with step 108 is repeated for state "M1."

[0216] 4 and 5, it can be seen that in the state of measurement point M1 (and the subsequent states of measurement points M2 to M7), the esophageal balloon pressure Peso clearly reflects the individual respiratory cycles. The maximum value of the Peso curve is assigned to the esophageal balloon pressure Peso_ei in the balloon probe 46 detected at the end of each inspiration phase, and the minimum value of the Peso curve is assigned to the esophageal balloon pressure Peso_ee in the balloon probe 46 detected at the end of each expiration phase.

[0217] This procedure is then repeated several times (see steps 114-130) to arrive at further measurement points M2-M7, E1, E2. At each of the further measurement points M2-M7, E1, E2, the esophageal balloon pressure Peso in the balloon probe 46 is detected over several respiratory cycles in the same way as described with reference to steps 108, 110 and 112, and the maximum value of the Peso curve is assigned to the esophageal balloon pressure Peso_ei in the balloon probe 46 detected at the end of the respective inspiration phase and the minimum value of the Peso curve is assigned to the esophageal balloon pressure Peso_ee in the balloon probe 46 detected at the end of the respective expiration phase.

[0218] Each of steps 110 to 130 is not shown in detail in the flowchart of FIG.

[0219] 4, it can be seen that each of these steps belongs to a certain amount of measuring fluid in the balloon probe 46, designated as measuring points S1, S2, M2-M7, E1, E2. The amount of measuring fluid in the balloon probe 46 always changes monotonically, in particular always decreases, during the transition from one of the measuring points S1, S2, M1-M7, E1, E2 to the next measuring point.

[0220] The step size, i.e. the amount by which the amount of measurement fluid in the balloon probe 46 changes when moving from one of the measurement points to the next, may always be the same. However, it is also possible that the amount by which the amount of measurement fluid in the balloon probe 46 changes is selected to be different in each step, as long as the change always occurs in the same direction, i.e. the amount always decreases or always increases. Since the assignment between each measurement point in the balloon probe 46 and the associated amount of measurement fluid is clear, for the sake of simplicity, the measurement points as well as the associated amount of measurement fluid in the balloon probe 46 will be referred to below as D1, S1, S2, M1-M7, E1, E2, etc.

[0221] For example, M1 indicates both the measurement point M1 and the corresponding amount of measurement fluid in the balloon probe 46. Similarly, for example, M7 indicates both the measurement point M7 and the corresponding amount of measurement fluid in the balloon probe 46. The same is true for the other measurement points M2 to M6 in the measurement series. The amount of measurement fluid M1 in the balloon probe 46 also represents the upper limit O of the measurement range. The amount of measurement fluid M7 in the balloon probe 46 also represents the lower limit U of the measurement range.

[0222] In FIG. 4 it can be seen that for measurement points M1 to M7 the detected signal of the esophageal balloon pressure Peso clearly indicates the individual respiratory cycles, but starting from measurement point E1 the detected esophageal pressure signal Peso starts to become unstable. This indicates that the balloon probe 46 is not sufficiently filled with the measuring fluid and therefore enters a region where it can no longer adequately react to the pressure changes caused by the individual respiratory cycles. It can be assumed that at measurement points E2 and E3 the balloon probe 46 is completely collapsed and the esophageal balloon pressure Peso hardly indicates any respiratory cycles. The measurement cycle ends when measurement point E3 is reached. At measurement point E3 the esophageal balloon pressure Peso is not detected and cannot be assigned.

[0223] The state M1 indicates the upper limit O of the measurement range available for the measurement cycle. The actual calibration is therefore limited to this measurement range defined by the measurement points M1 to M7. As can be seen from FIG. 4, for all measurement points M1 to M7 in the measurement range, the esophageal balloon pressure Peso detected in the balloon probe 46 is essentially within the same range. This shows that the balloon probe 46 forms together with the esophageal wall in this area a substantially elastic system that expands or contracts depending on the amount of measuring fluid in the balloon probe 46. These conditions remain the same until the lower limit U of the measurement range is reached, when the measurement point M7 is reached.

[0224] Between the measurement points M1 and M7, and thus in the measurement range between the upper limit O and the lower limit U of the amount of measurement fluid in the balloon probe 46, there is an approximately linear relationship between each predetermined amount of measurement fluid from the balloon probe 46 and each detected esophageal balloon pressure Peso. The slope of the line representing this linear relationship is approximately the same for the relationship between the esophageal balloon pressure Peso_ei detected at the end of the expiratory phase and the predetermined amount of measurement fluid in the balloon probe 46, and for the relationship between the esophageal balloon pressure Peso_ee detected at the end of the expiratory phase and the predetermined amount of measurement fluid in the balloon probe 46.

[0225] In the area outside the measurement range (measurement points S1, S2 or measurement points E1, E2), the relationship between the respective given amount of measurement fluid in the balloon probe 46 and the respective detected esophageal balloon pressure Peso changes significantly. This relationship is no longer approximately linear in the area outside the measurement range, but shows a much stronger increase and decrease of the detected esophageal balloon pressure Peso, the amount of measurement fluid in the balloon probe 46 becoming larger and smaller, respectively. The difference between the detected esophageal balloon pressure Peso_ei for a given amount of measurement fluid in the balloon probe 46 at the end of the expiratory phase and the detected esophageal balloon pressure Peso_ee at the end of the expiratory phase becomes rapidly smaller in the area outside the actual measurement range (measurement points M1 to M7) at measurement points S1, S2, S3, E1, E2b.

[0226] The graphs shown in Figures 5(a) and 5(b) show the importance of the calibration procedure on the measurement results. Figure 5(a) shows the measurement fluid V in the balloon probe 46 set as measurement points S1, S2, M1 to M7, E1, and E2 during a measurement period. b 5b shows a schematic representation of the detected esophageal balloon pressure Peso_ei in the balloon probe 46 at the end of the inspiration phase and the detected esophageal balloon pressure Peso_ee in the balloon probe 46 at the end of the expiration phase for each measurement point S1, S2, M1 to M7, E1, E2. FIG. 5b shows the resulting pressure difference dP between the esophageal balloon pressure Peso_ei at the end of the inspiration phase and the esophageal balloon pressure Peso_ee at the end of the expiration phase for each measurement point S1, S2, M1 to M7, E1, E2.

[0227] In the range of measurement points M1 to M7, the change in the esophageal balloon pressure Peso_ei detected by the balloon probe 46 at the end of the expiratory phase and the change in the esophageal balloon pressure Peso_ee detected by the balloon probe 46 at the end of the expiratory phase are b The resulting two curves Peso / V b The slope of is very flat and essentially the same for the esophageal pressure value at the end of the inspiration phase Peso_ei and the esophageal pressure value at the end of the expiration phase Peso_ee. Thus, in FIG. 5(b), the difference dP between the esophageal balloon pressure Peso_ei detected in the balloon probe 46 at the end of the inspiration phase and the esophageal balloon pressure Peso_ee detected in the balloon probe 46 at the end of the expiration phase remains essentially constant within the measurement range defined by the measurement points M1 to M7, but this difference dP becomes very small rapidly in the area outside this measurement range where the measurement points S1, S2, and E1, E2 are located.

[0228] From this, the optimal calibration of the esophageal balloon catheter 45 is within the measurement range defined by the measurement points M1 to M7 between the two vertical dotted lines O and U shown in FIG. 5(a), that is, within the volume V b The amount of fluid to be measured in the balloon probe 46 is within the range of bThis allows the calibration controller 450 to calculate the amount V of measurement fluid in the balloon probe 46 that is within the measurement range defined by the measurement points M1 to M7. b Select this setting. b is represented by the vertical line K in Fig. 5(a) and Fig. 5(b). This is the V b As can be seen in the horizontal portion of the curve, the V of the liquid in the balloon probe 46 after the calibration procedure is completed b is set as:

[0229] FIG. 5(b) shows the optimum V of the measurement fluid in the balloon probe 46 within the measurement range defined by the measurement points M1 to M7. opt 5(b) shows how the selection of is performed. In the measurement range, first, a measurement point is searched for at which the difference dP between the detected esophageal pressure Peso_insp at the balloon probe 46 at the end of the inhalation phase and the detected esophageal pressure Peso_exp at the balloon probe 46 at the end of the exhalation phase is maximum. In the example shown in FIG. 5(b), this is the case at the measurement point M4. Then, an allowable variation range is defined around this maximum difference dPmax. It is considered that the value of the difference dP within this variation range is not significantly different from the maximum value dPmax. In the example shown in FIG. 5(b), the allowable variation range is 10% of the maximum difference dPmax determined at the measurement point M4. This range is represented by the dashed line r in FIG. 5(b). The differences dP determined for the measurement points M3, M4, M5, M6 and M7 are within the variation range.

[0230] All these measurement points are in the vicinity of measurement point M4 and adjacent to each other. Therefore, the range of the amount of measurement fluid in the balloon probe 46 between measurement points M3 and M7 is considered to be equivalent in terms of filling the balloon probe 46 with the measurement fluid. This region is delimited by the vertical dashed lines a and b in FIG. 5(b). The optimal amount of measurement fluid in the balloon probe 46, V opt is selected to be the center of the region between lines a and b. In this way, the optimal volume of measurement fluid in the balloon probe 46, V opt is obtained by calibration. See the vertical line K in Figure 5(b). This quantity Vopt =K is set as the volume of fluid in the balloon probe 46 after calibration is completed. V in FIG. opt See the rightmost part of the curve.

[0231] After the calibration procedure is completed, the calibration controller 450 again supplies the balloon probe 46 with an amount of measurement fluid significantly greater than the amount corresponding to the measurement points M1-M7 of the measurement range in step 132 (see FIG. 3). In this step 132, the balloon probe 46 is again overstretched, a condition shown as "D2" in FIG. 4. Thereafter, in step 134, the calibration condition determined in the previous procedure is set by removing an appropriate amount of measurement fluid from the balloon probe 46, shown as "K" in FIG. 4, and the balloon probe 46 is returned to the optimal amount V. opt =K.

[0232] Optionally, a calibration state V opt It is also envisaged that the measurement cycle shown in Figures 3-5 may be followed by at least one further measurement cycle before =K is set. In such a case, the procedure returns from step 134 to step 108 to repeat the steps of the further measurement cycle as well as steps 110-130 of the first measurement cycle. In Figure 3, this is indicated by line 138.

[0233] The calibration controller 450 monotonically changes the amount of measurement fluid in the balloon probe 46 in at least two steps, starting from the starting value S1 and reaching the final value E3, so that the calibration procedure 100 can be completed in a short time, for example within a few minutes, to approach each of the measurement points S1, S2, M1-M7, E1, E2. This allows the optimal filling V of the balloon probe 46 to be determined. opt The calibration procedure 100 can be repeated during continuous ventilation to ensure that the esophageal balloon catheter 45 is always properly calibrated even if V changes during the course of ventilation. This allows for ventilation of a patient in the automatic ventilation mode for extended periods of time.

[0234] The esophageal balloon control system 400 according to the invention also comprises a fluid volume monitoring unit 470, which is designed to stepwise change the filling volume V of the measuring fluid in the balloon probe 46 at least once, in particular several times, and thus record the esophageal balloon pressure Peso detected in the balloon probe 46 at each filling volume V of the measuring fluid set as measuring point, and assign it to the respectively set filling volume V of the measuring fluid in the balloon probe 46. For this purpose, the pressure signal Peso detected by the balloon probe 46 is transmitted not only to the ventilation controller 180 but also to the fluid volume monitoring unit 470.

[0235] The fluid flow monitor 470 has access to the pumping device 430 (pump 425 and valve 420) and the flow sensor 410 of the esophageal balloon control system 400, as described above for the calibration controller 450. That is, the fluid flow monitor 470 can control the pump 425 and valve 420 of the pumping device 430 and receive signals from the flow sensor 410.

[0236] The flow sensor 410 can be designed similarly to the airway inlet flow sensor 36 located in the trachea 12. In this manner, in addition to determining flow, it is also possible to determine the esophageal balloon pressure Peso within the balloon probe 46.

[0237] The fluid volume monitor 470 can be realized as an independent component of "hardware". Alternatively, the fluid volume monitor 470 can be implemented as a computer program product, i.e. by a corresponding software program running on a processor, in particular a microprocessor or microcontroller. In this case, the software can be stored on a suitable local or network accessible storage medium. The software includes instructions coded as a computer program, which, when loaded into the memory of the processor and translated into a machine language, causes the processor to carry out the procedures described in more detail herein. Of course, a mixture of hardware and software implementations is also conceivable. A microprocessor or microcontroller may be associated with the control of the esophageal balloon control system 400, in particular may be part of the control of the esophageal balloon control system 400.

[0238] FIG. 6 is a flowchart showing an in vivo monitoring process for the fluid volume in the esophageal balloon catheter 45 by the fluid volume monitoring unit 470 according to an embodiment of the present invention.

[0239] A fluid volume monitoring procedure 500 for monitoring the fluid volume V in the esophageal balloon catheter 45 according to the flowchart shown in FIG. 6 begins in step 502 with the fluid volume monitoring unit 470 measuring the esophageal balloon pressure Peso at a fluid volume ("initial fluid volume") V0 present in the balloon probe 46 of the esophageal balloon catheter 45 and storing it as the initial esophageal balloon pressure Peso0.

[0240] In a second step 504, the fluid volume monitor 470 changes the existing volume V of the measurement fluid in the balloon probe 46 of the esophageal balloon catheter 45 to a first comparison volume V1 of the measurement fluid identified as the first comparison measurement point. The comparison volume V1 of the measurement fluid identified as the first comparison measurement point may be greater or less than the volume V0 of the measurement fluid currently present in the balloon probe 46 of the esophageal balloon catheter 45.

[0241] In the second step, additional measurement fluid may be delivered into the balloon probe 46 to increase the amount of the measurement fluid in the balloon probe 46 (V1 > V0). Alternatively, in the second step, the measurement fluid may be discharged or pumped out from the balloon probe 46 to reduce the amount of the measurement fluid in the balloon probe 46 (V1 < V0).

[0242] After the amount of the measurement fluid in the balloon probe 46 is set to the first comparison amount V1 of the measurement fluid designated as the comparison measurement point, the esophageal balloon pressure Pesoi in the balloon probe 46 of the esophageal balloon catheter 45 is measured in step 506 and stored as the first comparison esophageal balloon pressure Pesoi.

[0243] In the next step 508, the fluid amount monitoring unit 470 changes the amount of the measurement fluid in the balloon probe 46 of the esophageal balloon catheter 45 to the second comparison amount V2 of the measurement fluid designated as the second comparison measurement point. Thereby, a series of measurements including the first and second comparison amounts V1 and V2 of the measurement fluid as well as the initial fluid amount V0 are comparison amounts V of the measurement fluid that are greater than the amount V0 of the measurement fluid that was initially present in the balloon probe 46 of the esophageal balloon catheter 45 1,2 and comparison amounts V of the measurement fluid that are less than the amount V0 of the measurement fluid that was initially present in the balloon probe 46 of the esophageal balloon catheter 45 2,1 both of which are included.

[0244] That is, when the first comparison amount V1 of the measurement fluid designated as the first comparison measurement point is greater than the amount V0 of the measurement fluid that was initially present in the balloon probe 46 of the esophageal balloon catheter 45 (V1 > V0) (step 502), the second comparison amount V2 of the measurement fluid designated as the second comparison measurement point is preferably less than the amount V0 of the measurement fluid that was initially present in the balloon probe 46 of the esophageal balloon catheter 45 (V2 < V0), that is, V2 < V0 < V1.

[0245] When the first comparison amount V1 of the measurement fluid specified as the first comparison measurement point is smaller than the amount V0 of the measurement fluid initially present in the balloon probe 46 of the esophageal balloon catheter 45 (V1 < Va) (step 502), the second comparison amount V2 of the measurement fluid specified as the second comparison measurement point is preferably larger than the amount V0 of the measurement fluid initially present in the balloon probe 46 of the esophageal balloon catheter 45 (V2 > V0), and V1 < V0 < V2.

[0246] After the amount of the measurement fluid in the balloon probe 46 is set to the second comparison amount V2 of the measurement fluid designated as the second comparison measurement point, the esophageal balloon pressure Peso in the balloon probe 46 is measured in step 510 and stored as the second comparison esophageal balloon pressure Peso2.

[0247] In the next step 512, the first and second comparison esophageal balloon pressures Peso1, Peso2 are compared with the initial esophageal balloon pressure Peso0. In particular, the differences between the first and second comparison esophageal balloon pressures Peso1, Peso2 and the initial esophageal balloon pressure Peso0 are determined. Δ1 = |Peso1 - Peso0| Δ2 = |Peso2 - Peso0| When the first and second comparison esophageal balloon pressures Peso1, Peso2 are within a predetermined range centered on the initial esophageal balloon pressure Peso0, that is, when the difference Δ1 between the first comparison esophageal balloon pressure p1 and the initial esophageal balloon pressure Peso0 and the difference Δ2 between the second comparison esophageal balloon pressure Peso2 and the initial esophageal balloon pressure Peso0 are smaller than a predetermined limit value, Δ1 < Δ Limit and Δ2 < Δ Limit Also, the initial esophageal balloon pressure Peso0, and thus the initial fluid filling amount V0 as well, is within the "optimal range" between the measurement points M3 and M7 delimited by the lines a and b in Fig. 5b), and the pressure difference dP is essentially constant with respect to a (small) change in the fluid filling amount in the balloon probe 46.

[0248] Therefore, the fluid fill volume V0 in the balloon probe 46 is essentially the desired optimal fluid fill volume V opt Therefore, there is no need to adjust the fluid filling volume V in the balloon probe 46.

[0249] Thus, in the next step 514, the fluid fill volume V in the balloon probe 46 is returned to the fluid fill volume V0 that was present in the balloon probe 46 in the initial stage.

[0250] After the fluid fill volume V in the balloon probe 46 reaches the fluid fill volume V0 present in the balloon probe 46 in the initial state, the fluid volume monitoring unit 470 reports to the ventilation controller 180 in the next step 516 that adjustment of the fluid fill volume V in the balloon probe 46 is not required, and ventilation can continue without changing the fluid fill volume V in the balloon probe 46.

[0251] Alternatively, the first or second comparative esophageal balloon pressure Peso 1,2 and the initial esophageal balloon pressure Peso0 Δ 1,2 In addition to determining the first gradient grad1=Δp / ΔV of the change between the first comparative esophageal balloon pressure Peso and the initial esophageal balloon pressure Peso0, and the second gradient grad2=Δp / ΔV of the change between the second comparative esophageal balloon pressure Peso2 and the initial esophageal balloon pressure Peso0 in step 510, and calculates the gradients grad2 thus determined in step 512. 1,2 A given gradient threshold grad limit may be compared with

[0252] if the absolute values ​​of the first and second gradients are less than a predetermined gradient threshold; |grad 1,2 | <grad limit The initial esophageal balloon pressure Peso0, and therefore also the fluid filling volume V0 in the initial state, is in the “optimal range” between measurement points M3 and M7 bounded by lines a and b in FIG. 5b), where the pressure difference dP is assumed to be essentially constant with (small) changes in the fluid filling volume V at the balloon probe 46.

[0253] Therefore, the measurement of fluid V0 in the balloon probe 46 at the initial state is equal to the desired fluid fill volume V opt corresponds to, therefore, there is no need to adjust the fluid fill volume V in the balloon probe 46. In this case too, in step 514, the fluid fill volume V in the balloon probe 46 is returned to the fluid fill volume V0 present in the balloon probe 46. Thereafter, in step 514, the fluid volume monitoring unit 470 notifies the ventilation controller 180 that there is no need to adjust the fluid fill volume V in the balloon probe 46 and that ventilation can continue without changing the fluid fill volume V in the balloon probe 46.

[0254] However, the first or second comparative esophageal balloon pressure Peso 1,2 and the difference between the initial esophageal balloon pressure Peso0 Δ 1,2 At least one of the limits Δ limit and / or the gradient grad 1,2 At least one of the gradients is greater than a given gradient threshold. 1,2 >grad limit 5b), this indicates that the liquid fill volume V0 in the balloon probe 46 in the initial state was outside the convenient range between measurement points M3 and M7 bounded by lines a and b in FIG. 5b).

[0255] In order to regulate the fluid filling volume V in the balloon probe 46 so that it is in the region between the measurement points M3 and M7, again bounded by the lines a and b in FIG. 5b), which are recognized to be advantageous, the fluid volume monitor 470 in this case controls the filling controller 490 of the fluid filling system, which is also part of the esophageal balloon control system 400, to control, in step 518, that the fluid volume V in the balloon probe 46 is kept at a predetermined value V opt The predetermined fluid filling amount V opt may be greater or less than the initial fluid fill volume V0.

[0256] In order to adjust the volume of fluid V in the balloon probe 46, it is preferable to control the filling controller 490 so that the volume of fluid V in the balloon probe 46 is shifted in the direction of the first and second comparison quantities V1, V2 relative to the volume of fluid V0 present in the balloon probe 46 in the initial state, in which case the larger absolute value |grad 1,2 Gradient with | 1,2 has been decided.

[0257] Additionally, in step 520, the fluid volume monitor 470 reports to the ventilation controller 180 that the fluid fill volume V in the balloon probe 46 needs to be adjusted. The ventilation controller 180 then temporarily halts ventilation or adjusts the fluid fill volume V in the balloon probe 46 to the new desired volume V by the fill controller 490. opt It may continue without change in ventilation mode or ventilation parameters until it is changed to

[0258] After adjusting the fluid fill volume V in the balloon probe 46, the fluid volume monitoring procedure 500 may be repeated to monitor the fluid volume V. As a result, if the fluid fill volume V in the balloon probe 46 must be adjusted again, the fluid fill volume V in the balloon probe 46 may be adjusted again by the fill controller 490.

[0259] Alternatively, a recalibration 100 of the esophageal balloon catheter 45 may be performed as described with reference to FIG.

[0260] The new calibration 100 of the esophageal balloon catheter 45 is particularly 1,2 and the initial esophageal balloon pressure Peso0 Δ 1,2 At least one of the above-mentioned (first) limit value Δ limit A second predetermined limit value Δ limit2 (Δ limit2 >Δ limit ) is greater than (Δ 1,2 >Δ limit2 ) or gradient grad 1,2 At least one of the above-mentioned (first) threshold grad limit A second predetermined gradient threshold grad limit2 (grad limit2 >grad limit ) is greater than (grad 1,2 >grad limit2 ) may be implemented.

[0261] Recalibration 100 of the esophageal balloon catheter 45 may also be performed if repeated adjustments of the fluid fill volume V in the balloon probe 46 by the fill controller 490 do not produce the desired results.

[0262] If a new repeatable calibration 100 of the esophageal balloon catheter 45 does not produce the desired results, the esophageal balloon control system 400 indicates that the esophageal balloon catheter 45 should be replaced.

[0263] FIG. 7 shows the def 1 is a flowchart showing the sequence of a fluid filling procedure 600 executed by the filling controller 490 of the fluid filling system according to the present embodiment after being controlled by the esophageal balloon control system 400 and / or the ventilation controller 180 to fill the balloon probe 46 with a measurement fluid of 100 μg / mL.

[0264] A given amount of fluid to be measured V def is the respective desired fill volume V of the measurement fluid, in the sense of a target fluid volume when adjusting the amount of measurement fluid introduced into the balloon probe 46. The predetermined volume of measurement fluid is considered to be the optimum fill volume. def may be determined, for example, by a previously performed calibration procedure 100 as described above in relation to FIG.

[0265] The filling controller 490 may be implemented as an independent component "in hardware". Alternatively, the filling controller 490 may be implemented as a computer program product, i.e. by a corresponding software program running on a processor, in particular a microprocessor or microcontroller. In this case, the software may be stored on a suitable local or network accessible storage medium. The software includes instructions coded as a computer program, which, when loaded into the memory of the processor and translated into machine language, causes the processor to carry out the procedures described in more detail herein. Of course, a mixture of hardware and software implementations is also conceivable. The microprocessor or microcomputer may be part of the control of the fluid filling system and may be associated with the esophageal balloon control system 400 and / or the ventilation controller 180 depending on the design of the fluid filling system.

[0266] To ensure comparability and reproducibility of the filling state of the balloon probe 46 achieved after completion of the filling process, the filling controller 490 may be designed to execute an emptying procedure 610 before filling the balloon probe with the measurement fluid, in order to remove any measurement fluid present in the balloon probe 46 from the balloon probe 46.

[0267] The drain procedure 610 may include, for example, the fill controller 490 allowing the pressurized measurement fluid to flow out of the balloon probe 46 by opening the valve 420 of the esophageal balloon control system 400 (see FIG. 1 ) until pressure equalization with the environment occurs.

[0268] The balloon probe 46 can be emptied more easily and quickly using a pump device 430 (see FIG. 1) of the esophageal balloon control system 400, which is controlled by a filling controller 490 of the fluid filling system to pump the measurement fluid from the balloon probe 46 until a predetermined final pressure is reached. The final pressure may be a negative pressure, i.e. a pressure lower than the ambient pressure.

[0269] The evacuation procedure 610 for removing the measurement fluid located within the balloon probe 46 also provides a so-called zero volume V Null The procedure may include a step 620a for setting the zero volume V Null " refers to filling the esophageal balloon catheter 45 with the measurement fluid to a predetermined extent, where only the supply tube to the balloon probe 46 is filled with the measurement fluid, but the balloon probe 46 itself is completely folded and does not contain the measurement fluid.

[0270] Zero Volume V Null Once determined, the zero volume V Null can serve as a reproducible starting point for each filling step. Null may refer to a particular given pressure, for example ambient pressure.

[0271] Zero Volume V Null The procedure 620a for setting may specifically include the following steps: Step 621a: withdrawing the measurement fluid from the balloon probe 46 until a first predetermined negative pressure up1 in the balloon probe 46 is reached; Step 622: Introduce the measurement fluid into the balloon probe 46 until a second predetermined negative pressure up2 is reached in the balloon probe 46, the second predetermined negative pressure up2 being greater than the first predetermined negative pressure (up2>up1), i.e., a smaller negative pressure; and STEP 623: Introducing a predetermined amount of measurement fluid into balloon probe 46. The balloon of the balloon probe 46 is fully folded both when setting the first negative pressure up1 in step 621a and when setting the second negative pressure up2 in step 622a.

[0272] The "dead volume V of the esophageal balloon catheter 45 used tot " is known, the fill controller 490 of the fluid fill system determines the zero volume V Null , whereby the esophageal balloon catheter 45 is largely evacuated by the esophageal balloon catheter 45, e.g., the pump device 430, to the lowest possible negative pressure up0 in a first step 622a, and from the state thus achieved, a predetermined amount of measuring fluid V' def A predetermined amount of measurement fluid V' is introduced into the esophageal balloon catheter 45 (step 622b). def is the dead volume V tot , a reference pressure relative to zero volume, e.g., the ambient pressure p ambient It corresponds to the product multiplied by V' def =V tot xp ambient

[0273] Dead volume V tot depends on the specific parameters of the esophageal balloon catheter 45, such as the length and diameter of the delivery line 66 of the esophageal balloon catheter 45. tot is typically determined experimentally in advance for each esophageal balloon catheter 45 or for each series of esophageal balloon catheters 45.

[0274] The filling controller 490 may also be designed such that after one of the procedures 620a, 620b for removing the measurement fluid located in the balloon probe 46 has been performed, in an optional subsequent step 630, the fluid filling procedure 600 introduces a measurement fluid into the balloon probe 46 until a predetermined overpressure is reached in the balloon probe 46.

[0275] The introduction of the measurement fluid into the balloon probe 46 until a predetermined overpressure op is reached causes a predetermined V ref This is therefore done prior to the actual setting of V . This is done by emptying the balloon probe 46 as described above and setting the predetermined V of the measurement fluid in the balloon probe 46 in step 640. def and setting 630 .

[0276] After the predetermined overpressure op is reached in this intermediate step 630, in the next step 640, a quantity of the measurement fluid is removed from the balloon probe 46, either passively by pumping the measurement fluid with the valve 420 open, or actively by pumping the measurement fluid, to obtain a predetermined V of the measurement fluid in the balloon probe 46. det A given balloon pressure p def can be reached.

[0277] In a further embodiment, the esophageal balloon control system 400 controls the reference esophageal balloon pressure Peso base The reference esophageal balloon pressure Peso is continuously or repeatedly detected (step 650). base The given reference level Peso PN (Step 660) and the reference esophageal balloon pressure Peso base is the given reference level Peso PN The filling controller 490 may be designed to control the filling controller 490 to execute the previously described fluid filling procedure 600 for filling the balloon probe 46 with a measurement fluid when it is determined that the reference esophageal balloon pressure Peso has decreased by at least a predetermined amount compared to the reference esophageal balloon pressure Peso. baseIf is constantly used as a measure of the esophageal balloon pressure Peso, the balloon probe 46 may be filled during continuous ventilation.

[0278] "Reference esophageal balloon pressure Peso base " refers to a pressure or pressure differential that does not change over a number of consecutive deflation cycles and therefore can be a measure of changes in the filling state of the balloon probe.

[0279] Reference esophageal balloon pressure Peso base Specifically, Peso is the esophageal balloon pressure detected by the pressure determining device 300 and not superimposed on the ventilation profile reflecting the inhalation and exhalation process during ventilation.

[0280] For example, the esophageal balloon pressure Peso_ee measured at the end of the expiratory phase of successive ventilation cycles is the "reference esophageal balloon pressure" Peso base Alternatively, the esophageal balloon pressure Peso_ei measured at the end of the inspiratory phase of successive ventilation cycles can be defined as the reference esophageal balloon pressure Peso base It may be defined as:

[0281] The filling controller 490 thus designed continuously monitors whether the filling condition of the balloon probe 46, determined and set by, for example, the calibration procedure 100 described above, remains stable. The filling controller 490 adjusts the currently determined reference esophageal balloon pressure Peso base is the given reference value Peso PN If the liquid fill volume V in the balloon probe 46 deviates by more than a predetermined amount, the balloon probe 46 responds with a corresponding correction to the liquid fill volume V in the balloon probe 46.

[0282] In this way, losses of measurement fluid in the balloon probe 46, such as those caused by leakage, can be compensated for, at least as long as the losses of measurement fluid from the balloon probe 46 do not exceed a predetermined limit.

[0283] Such a filling controller 490 may, for example, be configured to monitor the duration of time during which the measured reference esophageal balloon pressure Peso decreases by more than a predetermined amount, or to monitor the duration of time during which the measured reference esophageal balloon pressure Peso decreases by more than a predetermined amount. base Losses can also be detected or leakage rates estimated by monitoring how much the concentration of β decreases after a given period of time.

[0284] If the amount of loss or leakage of the measurement fluid is known, the loss of the measurement fluid in the balloon probe 46 can be compensated for by refilling a predetermined amount of the measurement fluid into the balloon probe 46. The predetermined amount may be obtained from a predetermined amount of loss or leakage, and in particular, the predetermined amount may be obtained from multiplying the predetermined amount of loss or leakage by a corresponding period of time during which the loss was determined.

[0285] The replenishment of the measurement fluid is also monitored for an increase in esophageal balloon pressure Peso associated with the introduction of the measurement fluid into the balloon probe 46, and a predetermined esophageal balloon pressure Peso is then measured. soll replenishment may be performed to end as soon as

[0286] If the determined amount of loss or leakage rate exceeds a predetermined threshold beyond which replacement is not possible, the esophageal balloon control system 400 indicates that the esophageal balloon catheter 45 needs to be replaced.

[0287] As described above, the ventilation controller 180 and esophageal balloon control system 400 of the ventilation device 10 according to the present invention are designed such that the ventilation controller 180 can automatically control the esophageal balloon control system 400 and / or such that the esophageal balloon control system 400 can automatically control the ventilation controller 180.

[0288] The ventilation controller 180 and the esophageal balloon control system 400 may be specially designed to communicate bidirectionally with each other and specifically interact with each other.

[0289] The configuration in which the ventilation controller 180 is designed for automatic control of the esophageal balloon control system 400 means that in addition to the intended control and / or regulation functions with respect to ventilation itself, the ventilation controller 180 also has control and / or regulation functions for the esophageal balloon catheter 45, particularly with respect to its balloon probe 46.

[0290] This includes, among other things, the ventilation controller 180 controlling the esophageal balloon control system 400 to initiate predetermined procedures which may include, among other things, procedures for calibrating the balloon probe 46 (calibration controller 450), for filling the balloon probe 46 with a measurement fluid (fill controller 490), and / or for continuously monitoring the filling status of the balloon probe (fluid volume monitor 470), as previously described.

[0291] Additionally or alternatively, ventilation controller 180 may exert a control and / or regulatory influence over the sequence of procedures processed by esophageal balloon control system 400. Such control or regulatory influence may include, for example, ventilation controller 180 providing values ​​of currently set ventilation parameters to esophageal balloon control system 400, which in turn initiates, controls, regulates, and / or terminates predetermined control procedures acting on the esophageal balloon of balloon probe 46 based on these values, in particular at least one of the control procedures described above.

[0292] By bidirectional communication and / or interaction between the ventilation controller 180 and the esophageal balloon control system 400, optimal interaction between the ventilation controller 180 and the esophageal balloon control system 400 can be achieved, and the respective procedures performed are coordinated and synchronized. In particular, the control procedures performed by the esophageal balloon control system 400 acting on the esophageal balloon catheter 45 can be performed without interrupting the continuous ventilation.

[0293] The ventilation controller 180 may also provide the esophageal balloon control system 400, via the bidirectional connection 150, with information important for the execution of a particular control procedure for the esophageal balloon catheter 45. This allows for the modification of ventilation parameters or detected variables occurring during ventilation to be taken into account when executing a control procedure in the esophageal balloon control system 400. The control procedures may include, in particular, the control procedures described above for calibrating the balloon probe 46, for filling the balloon probe 46, and for monitoring the amount of fluid in the balloon probe 46.

[0294] How changes in ventilation parameters or variables detected during ventilation can be taken into account when implementing control procedures in the balloon control device 400 is described in detail below, for example in the case of multiple ventilation modes, in which the ventilation controller 180 adjusts the tidal volume V applied during breath-to-breath mechanical ventilation. tidal Therefore, in these ventilation methods, the tidal volume V tidal is not a ventilation parameter that remains constant over the entire ventilation period, but is a value that varies from breath to breath.

[0295] Depending on the ventilation mode, instead of breath one may refer to a ventilation stroke, a breathing cycle or a ventilation cycle, and therefore in the following the expressions breath, ventilation stroke, breathing cycle and ventilation cycle are used synonymously.

[0296] The tidal volume V applied to each breath tidal is the tidal pressure p, which represents the pressure difference in the lungs between the end of the inspiratory phase and the end of the expiratory phase. tidal The respective tidal volume V tidal may affect the execution of the control procedure of the esophageal balloon control system 400.

[0297] For example, the optimal V of the measurement fluid in the balloon probe 46 of the esophageal balloon catheter 45 opt In the in vivo calibration oftidal We assume that V does not change. Therefore, during calibration, the tidal volume V applied to each breath is tidal remains as constant as possible.

[0298] For this reason, the calibration of the balloon probe 46 of the esophageal balloon catheter 45 is performed based on the applied tidal volume V tidal This is only possible in ventilation modes where is kept constant.

[0299] However, in a ventilator 10 designed in accordance with an embodiment of the present invention using two-way communication between the ventilation controller 180 and the esophageal balloon control system 400, the ventilation controller 180 determines the tidal volume V delivered in each breath. tidal The magnitude of the tidal volume V delivered to the balloon probe 46 can be transmitted to the esophageal balloon control system 400. tidal may be taken into account when calibrating the esophageal balloon catheter 45.

[0300] For example, the difference between the esophageal balloon pressure Peso_ei at the end of the expiratory phase and the esophageal balloon pressure Peso_ee at the end of the expiratory phase is calculated as the tidal volume V applied to each exhalation. tidal In particular, the pressure difference and the tidal volume V tidal The quotient of V and V can be used as a standard. tidal This allows calibration of the balloon probe 46 even during continuous ventilation in ventilation modes where the ventilation rate is not constant.

[0301] In addition to the automatic setting of ventilation parameters such as PEEP or Paw_max, the ventilator 10 may be designed for a largely automated display of information regarding ventilation. For example, certain ventilation parameters such as Ptp may be displayed on the display of the ventilator 10. Optionally, additional information may be displayed, such as whether the esophageal balloon catheter 45 is operated in normal or special mode, in particular during the calibration procedure 100, the fluid volume monitoring procedure 500, and / or the fluid filling procedure 600.

[0302] The ventilation controller 180 may be designed, inter alia, to control and / or regulate the esophageal balloon control system 400 according to pressure values ​​provided by the pressure determination system 300. This interaction may, inter alia, be bidirectional. In this case, the intelligence of the entire system, including the ventilation controller 180 and the esophageal balloon control system 400, may be located largely on the side of the ventilation controller 180, which in this case performs all control and / or regulation procedures relating to the esophageal balloon catheter 45, including, for example, calibration 100 of the esophageal balloon catheter 45, monitoring the amount of fluid in the esophageal balloon of the balloon probe 46 (fluid amount monitoring procedure 500), and refilling or filling the esophageal balloon of the balloon probe 46 with fluid (fluid filling procedure 600). In such a configuration, the esophageal balloon control system 400 is configured only to execute control and / or regulation commands provided to the esophageal balloon control system 400 by the ventilation controller 180.

[0303] In other embodiments, a greater portion of the intelligence of the overall system 10 may be realized in the esophageal balloon control system 400. In particular, in such embodiments, the esophageal balloon control system 400 may largely independently execute the control / regulation procedures associated with the esophageal balloon catheter 45, such as the calibration 100 of the esophageal balloon catheter 45, the monitoring 500 of the fluid volume in the esophageal balloon of the balloon probe 46 by the fluid volume monitor 470, and the possible refilling 600 of the fluid volume in the esophageal balloon of the balloon probe 46 by the fill controller 490, after being requested to do so ("triggered") by the ventilation controller 180.

[0304] This may include, in particular, parameters and measurement variables that are transmitted from the ventilation controller 180 to the esophageal balloon control system 400 and taken into account by the esophageal balloon control system when performing control and / or adjustment procedures relating to the esophageal balloon catheter 45, as described above. Conversely, parameters and measurements may be transmitted from the esophageal balloon control system 400 to the ventilation controller 180 in order to control and, if necessary, adjust ventilation based on the parameters and measurements transmitted from the esophageal balloon control system 400 to the ventilation controller 180, as described above.

[0305] In embodiments in which the pressure determination system 300 is at least partially associated with an esophageal balloon control system 400, the esophageal balloon control system 400 determines the esophageal balloon pressure p eso may be configured to provide a signal reflective of the

[0306] In further embodiments, an even greater portion of the overall system intelligence and control may be realized in the esophageal balloon control system 400.

[0307] Thus, the feature that the esophageal balloon control system 400 is designed for automatic control of the ventilation controller 180 is that the esophageal balloon control system 400 is configured to control the esophageal balloon pressure peso In addition to transmitting signals representing the above, it also represents performing a control / regulation function for the ventilation controller 180.

[0308] For example, the esophageal balloon control system 400 may control the ventilation controller 180 to initiate a given procedure. Additionally or alternatively, the esophageal balloon control system 400 may control and / or coordinate the course of a particular procedure performed by the ventilation controller 180. For example, the esophageal balloon control system 400 may instruct the ventilation controller 180 to "freeze" or hold the currently set values ​​of ventilation parameters for a period of time.

[0309] By "freezing" or locking the currently set ventilation parameters, the esophageal balloon control system 400 prevents the ventilation controller 180 from changing the frozen / locked ventilation parameters for a certain period of time while the esophageal balloon control system 400 is performing certain procedures, in particular one of the previously described procedures for calibrating the balloon probe 46 (fluid filling procedure 600), filling the balloon probe 46, and / or monitoring the amount of fluid in the balloon probe 46 (fluid volume monitoring procedure 500).

[0310] To this end, the esophageal balloon control system 400 may control the ventilation controller 180 to not allow changes to certain ventilation parameters and / or ventilation modes after activation or initiation of an esophageal balloon control procedure 100, 500, 600 until the esophageal balloon control procedure is terminated. In this manner, undesirable interactions between a performed esophageal balloon control procedure 100, 500, 600 and concurrent changes in ventilation parameters and / or ventilation modes that may affect the execution of the esophageal balloon control procedure 100, 500, 600 and / or ongoing ventilation may be avoided.

[0311] The ventilation controller 180 may also be configured to not allow changes to the predetermined ventilation parameters 192A, 192B, 192C, 192D and / or ventilation modes 190A, 190B, 190C, 190D that begin a predetermined time prior to the scheduled activation or initiation of an esophageal balloon control procedure 100, 500, 600 until the scheduled esophageal balloon control procedure 100, 500, 600 is completed. To prevent blockage of the ventilation controller 180, the ventilation controller 180 may re-enable changes to the predetermined ventilation parameters 192A, 192B, 192C, 192D and / or ventilation modes 190A, 190B, 190C, 190D if the esophageal balloon control procedure 100, 500, 600 has not been initiated within the predetermined time.

[0312] The ventilation controller 180 and / or the esophageal balloon control system 400 may generate a warning if a change in a given ventilation parameter 192A, 192B, 192C, 192D and / or ventilation mode 190A, 190B, 190C, 190D is forced, for example by a corresponding user input, at a predetermined time before the initiation of the esophageal balloon control procedure 100, 500, 600. Additionally or alternatively, the esophageal balloon control system 400 may delay the initiation of the esophageal balloon control procedure 100, 500, 600 so that the esophageal balloon control procedure 100, 500, 600 proceeds unperturbed by the change in the ventilation parameter 192A, 192B, 192C, 192D and / or ventilation mode 190A, 190B, 190C, 190D.

[0313] The ventilation controller 180 and / or the esophageal balloon control system 400 may be specifically configured to initiate the esophageal balloon control procedures 100, 500, 600 at one or more predetermined times or at predetermined time intervals. In this manner, operation of the ventilator 10 may be further automated and operational reliability may be improved.

[0314] The ventilation controller 180 and / or esophageal balloon control system 400 may be configured, in particular, such that if a change in a predetermined ventilation parameter 192A, 192B, 192C and / or ventilation mode 190A, 190B, 190C, 190D occurs within a predetermined period of time prior to initiation of an esophageal balloon control procedure 100, 500, 600, the initiation of the esophageal balloon control procedure 100, 500, 600 is postponed until the change in ventilation parameter 192A, 192B, 192C, 192D and / or ventilation mode 190A, 190B, 190D is completed, so that the esophageal balloon control procedure 100, 500, 600 can be performed without being affected and / or hindered by the change in ventilation parameter 192A, 192B, 192C, 192D and / or ventilation mode 190A, 190B, 190C, 190D.

[0315] In addition, the ventilation controller 180 and / or the esophageal balloon control system 400 may postpone any change in at least one predetermined ventilation parameter 192A, 192B, 192C, 192D and / or ventilation mode 190A, 190B, 190C, 190D that would be made a predetermined time interval before or during a selected esophageal balloon control procedure 100, 500, 600 until the selected and already started esophageal balloon control procedure 100, 500, 600 is completed, in order to prevent the esophageal balloon control procedure 100, 500, 600 from being affected by the change in the at least one predetermined ventilation parameter 192A, 192B, 192C, 192D and / or ventilation mode 190A, 190B, 190C, 190D.

[0316] The communication between the esophageal balloon control system 400 and the ventilation controller 180, through which the esophageal balloon control system 400 acts on the ventilation controller 180, improves the interaction between the ventilation controller 180 and the esophageal balloon control system 400 so that the procedures performed by the ventilation controller 180 and the esophageal balloon control system 400 are coordinated with each other and performed in a synchronized manner.

[0317] Additionally, the ventilator 10 designed in accordance with the present invention allows for more accurate consideration of the pressure Ppl prevailing in the pleural cavity 44 by the esophageal balloon catheter 45 and allows for flexible adaptation of the measurements provided by the esophageal balloon catheter 45 to changing environmental conditions during continuous ventilation, particularly during highly automated continuous ventilation.

[0318] According to the present invention, when the ventilation controller 180 of the ventilation device 10 and the esophageal balloon control system 400 of the esophageal balloon catheter 45 are designed to communicate bidirectionally, continuous mutual monitoring of the ventilation controller 180 and the esophageal balloon control system 400 is possible, which allows early detection and correction of malfunctions.

[0319] Furthermore, ventilation parameters, control and regulation variables may be adapted to changes in environmental conditions during continuous ventilation without the need for manual intervention. In particular, with the ventilator 10 according to the invention, ventilation does not need to be interrupted in order to recalibrate and / or resume certain functions and / or procedures of ventilation. It is also possible to adjust the filling volume V of the measuring fluid in the balloon probe 46 without interrupting continuous ventilation.

[0320] Also, due to adaptation of the ventilation and the overall system performing the ventilation, the esophageal balloon catheter 45 may be fully recalibrated as part of the calibration procedure 100 without interrupting ongoing ventilation. Such recalibration without interrupting ongoing ventilation is feasible with the ventilator 10 according to the present invention, even when ventilation is performed by a fully automatic ventilation mode of ventilation with a closed control loop, such as, for example, adaptive assisted ventilation (ASV ventilation) or the INTELLiVENT-ASV mode developed by the applicant.

Claims

1. A device (15) for automatically setting predetermined ventilation parameters (192A, 192B, 192C, 192D) by a ventilation device (10) and / or for automatically displaying information related to mechanical ventilation, comprising: a pressure determination system (300) for determining a transpulmonary pressure (Ptp) based on an esophageal balloon catheter (45) insertable into the esophagus (34), the pressure determination system (300) including a balloon probe (46) for determining an esophageal balloon pressure (Pso); an esophageal balloon control system (400) for automatically monitoring and / or configuring the proper filling of the balloon probe (46) of the esophageal balloon catheter (45) in vivo; A ventilation controller (180); Equipped with the ventilation controller (180) is configured to set the ventilation parameters (192A, 192B, 192C, 192D) specified by the ventilation device (10) and / or display the information regarding mechanical ventilation based on the transpulmonary pressure (Ptp) determined by the pressure determination system (300); the ventilation controller (180) is further configured to automatically control the esophageal balloon control system (400) and / or the esophageal balloon control system (400) is further configured to automatically control the ventilation controller (180).

15. An apparatus (15).

2. The ventilation parameters (192A, 192B, 192C, 192D) are pressures.

2. The device (15) according to claim 1 .

3. The ventilation parameters (192A, 192B, 192C, 192D) are positive end-expiratory pressure (PEEP) and / or maximum airway pressure (Paw_max), 3. The device (15) according to claim 2 .

4. The information regarding the mechanical ventilation is transpulmonary pressure (Ptp).

2. The device (15) according to claim 1 .

5. The transpulmonary pressure (Ptp) is the transpulmonary pressure at the end of the expiratory phase (Ptp_ee) and / or the transpulmonary pressure at the end of the inspiratory phase (Ptp_ei), 2. The device (15) according to claim 1 .

6. the ventilation controller (180) is configured to control / adjust the esophageal balloon control system (400) according to pressure values ​​provided by the pressure determination system (300); 2. The device (15) according to claim 1 .

7. the esophageal balloon control system (400) is configured to execute an esophageal balloon control procedure (100, 500, 600) according to control commands provided by the ventilation controller (180); 2. The device (15) according to claim 1 .

8. the esophageal balloon control system (400) is configured to transmit a predetermined esophageal balloon control signal to the ventilation controller (180); said ventilation controller (180) is configured to set / control / adjust / display predetermined ventilation parameters (192A, 192B, 192C, 192D) and / or ventilation modes (190A, 190B, 190C, 190D) according to said esophageal balloon control signal; 2. The device (15) according to claim 1 .

9. the ventilation controller (180) is configured to not allow changes to predetermined ventilation parameters (192A, 192B, 192C, 192D) and / or ventilation modes (190A, 190B, 190C, 190D) from a predetermined time before activation or initiation of an esophageal balloon control procedure (100, 500, 600) until the esophageal balloon control procedure (100, 500, 600) has ended or has not been initiated within the predetermined time; 9. Apparatus (15) according to claim 8.

10. The ventilation controller (180) is configured not to allow changes to predetermined ventilation parameters (192A, 192B, 192C, 192D) and / or ventilation modes (190A, 190B, 190C, 190D) after activation or initiation of an esophageal balloon control procedure (100, 500, 600) until the esophageal balloon control procedure (100, 500, 600) is terminated.

2. The device (15) according to claim 1 .

11. The ventilation controller (180) is configured to not allow changes to predetermined ventilation parameters (192A, 192B, 192C, 192D) and / or ventilation modes (190A, 190B, 190C, 190D) from a predetermined time before activation or initiation of an esophageal balloon control procedure (100, 500, 600) until the esophageal balloon control procedure (100, 500, 600) has ended or has not been initiated within the predetermined time.

10. Apparatus (15) according to claim 9.

12. the ventilation controller (180) and / or the esophageal balloon control system (400) are configured such that an alert is generated if a change in a predetermined ventilation parameter (192A, 192B, 192C, 192D) and / or ventilation mode (190A, 190B, 190C, 190D) is forced after a predetermined time point before the start of an esophageal balloon control procedure (100, 500, 600); 2. The device (15) according to claim 1 .

13. The change is forced by a corresponding user input.

13. Apparatus (15) according to claim 12.

14. The ventilation controller (180) and / or the esophageal balloon control system (400) an esophageal balloon control procedure (100, 500, 600) configured to be initiated at one or more predetermined time points; configured to postpone initiation of the esophageal balloon control procedure (100, 500, 600) until the change in the ventilation parameters (192A, 192B, 192D) and / or the ventilation mode (190A, 190C, 190D) is completed if a change in the predetermined ventilation parameters (192A, 192B, 192C, 192D) and / or the ventilation mode (190A, 190B, 190C, 190D) is made within a predetermined period of time prior to initiation of an esophageal balloon control procedure (100, 500, 600); 2. The device (15) according to claim 1 .

15. the ventilation controller (180) and / or the esophageal balloon control system (400) are configured such that changes to certain ventilation parameters (192A, 192B, 192C, 192D) and / or ventilation modes (190A, 190B, 190C, 190D) made after activation or initiation of an esophageal balloon control procedure (100, 500, 600) are postponed until the esophageal balloon control procedure (100, 500, 600) is completed; 2. The device (15) according to claim 1 .

16. the ventilation controller (180) and / or the esophageal balloon control system (400) are configured such that an esophageal balloon control procedure (100, 500, 600) is initiated according to a predetermined time interval; if a deferrable change in a predetermined ventilation parameter (192A, 192B, 192C, 192D) and / or ventilation mode (190A, 190B, 190C, 190D) is made within a predetermined period of time prior to initiation of an esophageal balloon control procedure (100, 500, 600), the ventilation controller (180) is configured to postpone initiation of the change in the ventilation parameter (192A, 192B, 192C, 192D) and / or ventilation mode (190A, 190B, 190C, 190D) until the esophageal balloon control procedure (100, 500, 600) is completed; 2. The device (15) according to claim 1 .

17. the pressure determining system (300) comprising a sensor configured to determine the esophageal balloon pressure; 2. The device (15) according to claim 1 .

18. The sensor has an esophageal balloon catheter (45) insertable into the esophagus (34), The esophageal balloon catheter (45) includes a balloon probe (46) and a device for detecting pressure within the balloon probe (46) in vivo.

18. Apparatus (15) according to claim 17.

19. the esophageal balloon control system (400) including a pump device (430) for filling the balloon probe (46) with a measurement fluid and / or for removing a measurement fluid from the balloon probe (46) after the balloon probe (46) is positioned in the esophagus (34); 2. The device (15) according to claim 1 .

20. the esophageal balloon control system (400) is configured to incrementally change each set amount of measurement fluid in the balloon probe (46); 20. Apparatus (15) according to claim 19.

21. The esophageal balloon control system (400) is configured to change the amount of measurement fluid in the balloon probe (46) in one step or multiple steps, detect the esophageal balloon pressure (Pesoi) as measurement points (S1, S2, M1, M2, ..., M7, E1, E2, E3) for each of the stepwise set amounts of measurement fluid in the balloon probe (46), and assign it to each of the set amounts (Vi) of measurement fluid in the balloon probe (46).

21. Apparatus (15) according to claim 20.

22. the esophageal balloon control system (400) and / or the ventilation controller (180) comprises at least one of a fluid volume monitor (470), a fluid filling system having a filling controller (490), and a calibration controller (450); at least when the esophageal balloon control system (400) comprises at least one of a fluid volume monitor (470), a filling controller (490) and a calibration controller (450), the ventilation controller (180) bidirectionally interacts with at least one of the fluid volume monitor (470), the filling controller (490) and the calibration controller (450) to control the esophageal balloon control system (400) to initiate a predetermined fluid volume monitoring procedure (500), a fluid filling procedure (600) and / or a calibration procedure (100) and / or to control the execution of a fluid volume monitoring procedure (500), a fluid filling procedure (600) and / or a calibration procedure (100); 2. The device (15) according to claim 1 .

23. The esophageal balloon control system (400) comprising a calibration controller (450) configured to incrementally vary an amount of measurement fluid in the balloon probe (46); the calibration controller (450) is configured to record the esophageal balloon pressure (Peso i ) detected by the pressure sensor for each of the stepped amounts (V i ) of measurement fluid in the balloon probe (46) as measurement points (S1, S2, M1, M2, ..., M7, E1, E2, E3) and assign them to each of the stepped amounts of measurement fluid in the balloon probe (46); 23. Apparatus (15) according to claim 22.

24. The ventilation controller (180) and / or the esophageal balloon control system (400) (i) Change of settings: change of positive end expiratory pressure (PEEP), change of predetermined maximum airway pressure (pawmax), change of tidal volume (Vt), change of tidal stroke (IE), change of ventilation rate (BR); (ii) Changes in actual values: end-expiratory pressure (Pes_ee), difference between end-inspiratory pressure and end-expiratory pressure (Pes_ei-Pes_ee), breath-to-breath variation in esophageal (34) pressure, chest wall compliance (Ccw=Vt / (Pes_ei-Pes_ee)); initiating a calibration procedure (100), a fluid volume monitoring procedure (500), and / or a fluid filling procedure (600) in response to one of the parameters changing by more than a predetermined value; 23. Apparatus (15) according to claim 22.

25. The esophageal balloon control system (400) comprises a calibration controller (450) configured to incrementally vary an amount of measurement fluid in the balloon probe (46); The calibration controller (450) adjusts the volume of measurement fluid (V) in the balloon probe (46) in a stepped manner. ｉ ), the esophageal balloon pressure (Peso ｉ ) as measurement points (S1, S2, M1, M2, ..., M7, E1, E2, E3) and assigned to each of the set amounts of measurement fluid in the balloon probe (46).

25. Apparatus (15) according to claim 24.

26. The esophageal balloon control system includes a filling controller (490); After being controlled, the filling controller (490) is configured to execute a fluid filling procedure (600) for filling the balloon probe (46) with a predetermined amount of measurement fluid.

23. Apparatus (15) according to claim 22.

27. the filling controller (490) is configured to perform a draining procedure (610) for removing a measurement fluid from within the balloon probe (46) before starting a fluid filling procedure for filling the balloon probe (46); 27. Apparatus (15) according to claim 26.

28. The step of discharging the measurement fluid (610) is performed at zero volume (V Ｎｕｌｌ ) 28. Apparatus (15) according to claim 27.

29. Zero volume (V ０ The step (620a) for setting (i) A first predetermined negative pressure (up １ removing (621a) measurement fluid from the balloon probe (46) until the balloon probe (46) reaches a (ii) The inside of the balloon probe (46) is at the first predetermined negative pressure (up １ ) is greater than the second predetermined negative pressure (up ２ 6. Injecting a measurement fluid into the balloon probe (46) until the measurement fluid reaches a predetermined volume (622a); (iii) introducing (623a) a quantity of a measurement fluid into the balloon probe (46); Including, 29. Apparatus (15) according to claim 28.

30. the filling controller is configured to execute, following the evacuation step (610) of removing the measurement fluid from the balloon probe (46), a step (630) of introducing a measurement fluid into the balloon probe (46) until a predetermined overpressure (op) is reached in the balloon probe (46); 28. Apparatus (15) according to claim 27.

31. The esophageal balloon control system (400) controls the reference esophageal balloon pressure (Peso ｂａｓｅ ) and detects the reference esophageal balloon pressure (Peso ｂａｓｅ ) drops by more than a predetermined amount, control the filling controller to execute the fluid filling procedure (600) for filling the balloon probe (46) with a measurement fluid.

28. Apparatus (15) according to claim 27.

32. The esophageal balloon control system (400) comprises a fluid volume monitor (470); the fluid volume monitoring unit (470) is configured to perform a fluid volume monitoring procedure (500) after activation to verify a desired filling of the measurement fluid in the balloon probe (46); 23. Apparatus (15) according to claim 22.

33. The fluid volume monitoring unit (470) after starting the procedure for ascertaining a desired filling of the measuring fluid in the balloon probe (46), gradually changing the existing amount of measuring fluid in the balloon probe (46); For each comparative amount of measurement fluid in the balloon probe (46) thus set, a comparative esophageal balloon pressure is detected as a comparative measurement point; configured to assign it to each of said comparative quantities of measuring fluid in said balloon probe (46); 33. Apparatus (15) according to claim 32.

34. After the start of the fluid volume monitoring procedure (500), the fluid volume monitor (470) measures the existing volume (V) of the measurement fluid in the balloon probe (46) to verify the desired filling of the measurement fluid in the balloon probe (46). ０ ) by dividing the existing volume of measurement fluid (V ０ ) is larger than the first comparison measurement point (M １ The first comparison quantity (V １ ), 34. Apparatus (15) according to claim 33.

35. After the start of the fluid volume monitoring procedure (500), the fluid volume monitor measures the existing volume (V) of measurement fluid in the balloon probe (46) to verify the desired filling of measurement fluid in the balloon probe (46). ０ ) by dividing the existing volume of measurement fluid (V ０ ) is smaller than the comparison measurement point (M ２ A second comparison quantity (V ２ ), 35. Apparatus (15) according to claim 34.

36. The first comparison quantity (V １ The comparative esophageal balloon pressure (Peso １ ) and the second comparative amount (V ２ The comparative esophageal balloon pressure (Peso ２ ) is the esophageal balloon pressure (Peso) associated with the existing amount of measurement fluid in the balloon probe (46). ０ ), the fluid volume monitor determines that the existing amount of measurement fluid in the balloon probe (46) corresponds to the desired amount of measurement fluid in the balloon probe (46).

36. Apparatus (15) according to claim 35.

37. The first comparison quantity (V １ The comparative esophageal balloon pressure (Peso １ ) and the existing volume of measurement fluid in the balloon probe (46) (V ０ The esophageal balloon pressure (Peso ０ ) and a first gradient (grad １ ) and the second comparison quantity (V ２ The comparative esophageal balloon pressure (Peso ２ ) and the existing volume of measurement fluid in the balloon probe (46) (V ０ The esophageal balloon pressure (Peso ０ ) and a second gradient (grad ２ ) is a predetermined first threshold (grad ｌｉｍｉｔ１ ), the fluid volume monitor determines that the existing amount of measurement fluid in the balloon probe (46) corresponds to the desired amount of measurement fluid in the balloon probe (46).

37. Apparatus (15) according to claim 36.

38. The fluid volume monitor (470) detects the first gradient (grad １ ) and the second gradient (grad ２ ) is the first threshold value (grad ｌｉｍｉｔ１ 23 , when it is determined that the measured value of the fluid amount monitoring unit (470) is greater than the predetermined value, the fluid amount monitoring unit (470) is configured to control the filling controller (490) of the fluid filling system to execute the fluid filling procedure (600) of claim 22, which fills the balloon probe (46) with a predetermined amount of a measurement fluid, The two gradients (grad １ ), (grad ２ The first and second comparison amounts (V １ , V ２ ) in the direction of filling, the existing amount of measuring fluid in the balloon probe (46) (V ０ ) a new predetermined filling is set that is shifted relative to 38. Apparatus (15) according to claim 37.

39. The fluid volume monitor (470) detects the first gradient (grad １ ) and the second gradient (grad ２ ) is greater than or equal to the second threshold (grad ｌｉｍｉｔ２ ), the calibration controller (450) is configured to perform a calibration procedure (100) according to claim 16, The second threshold (grad ｌｉｍｉｔ２ ) is the first threshold value (grad ｌｉｍｉｔ１ ) is greater than 38. Apparatus (15) according to claim 37.

40. the esophageal balloon control system (400) is configured to control the fluid volume monitoring unit (470) in response to changes in ventilation parameters (192A, 192B, 192C, 192D) to execute a fluid volume monitoring procedure (500) for confirming a predetermined filling of the measurement fluid in the balloon probe (46); 33. Apparatus (15) according to claim 32.

41. A device (15) according to any one of claims 1 to 40 for automatically setting predetermined ventilation parameters (192A, 192B, 192C, 192D) by the ventilation device (10) and / or for automatically displaying information on mechanical ventilation. A ventilation device (10).

42. An esophageal balloon control system (400) for an esophageal balloon catheter (45) insertable into an esophagus (34), comprising: a balloon probe (46) for determining esophageal balloon pressure (Peso); The esophageal balloon control system (400) comprises a sensor (410); the sensor (410) is configured to detect an esophageal balloon pressure and transmit the detected esophageal balloon pressure to a pressure determination system (300) that determines a transpulmonary pressure (Ptp) based on the detected esophageal balloon pressure (Peso); the esophageal balloon control system (400) is configured to automatically monitor and / or regulate operational filling of the balloon probe (46) of the esophageal balloon catheter (45) in vivo; The esophageal balloon control system (400) is further configured to receive control signals from a ventilation controller (180) that automatically controls the esophageal balloon control system (400) and / or automatically controls the ventilation controller (180).

1. An esophageal balloon control system (400).

43. The balloon probe (46) in the device (15) according to any one of claims 1 to 40, determines the esophageal balloon pressure (Peso); said device (15) being a device for automatically setting ventilation parameters (192A, 192B, 192C, 192D) specified by the ventilation device (10); 43. The esophageal balloon control system (400) of claim 42.

44. The transpulmonary pressure (Ptp) is the transpulmonary pressure at the end of the expiratory phase (Ptp_ee) and / or the transpulmonary pressure at the end of the inspiratory phase (Ptp_ei), 43. The esophageal balloon control system (400) of claim 42.

45. the esophageal balloon control system (400) is configured to operate according to control commands provided by and / or to control the ventilation controller (180) of the ventilation device (10); 43. The esophageal balloon control system (400) of claim 42.

46. An esophageal balloon catheter (45) for determining esophageal balloon pressure (Peso) in vivo after insertion into a patient's esophagus (34), comprising: A balloon probe (46) for determining the esophageal balloon pressure (Peso); and an esophageal balloon control system (400) according to claim 42. An esophageal balloon catheter (45).

47. The esophageal balloon catheter (45) is provided in a device (15) according to any one of claims 1 to 40, the device (15) being a device for automatically setting ventilation parameters (192A, 192B, 192C, 192D) specified by a ventilation device (10) and / or for automatically displaying information relating to mechanical ventilation.

47. An esophageal balloon catheter (45) according to claim 46.

48. The ventilation parameter (192A, 192B, 192C, 192D) is a pressure.

48. An esophageal balloon catheter (45) according to claim 47.

49. The pressure is a positive end-expiratory pressure (PEEP) and / or a maximum airway pressure (Paw_max).

49. An esophageal balloon catheter (45) according to claim 48.

50. The information regarding the mechanical ventilation is transpulmonary pressure (Ptp).

48. An esophageal balloon catheter (45) according to claim 47.

51. A ventilation controller (180) for an apparatus (15) for automatically setting ventilation parameters (192A, 192B, 192C, 192D) specified by a ventilation device (10) and / or for automatically displaying information related to mechanical ventilation, comprising: the ventilation controller (180) is configured to set the ventilation parameters (192A, 192B, 192C, 192D) specified by the ventilation device (10) based on a transpulmonary pressure (Ptp) determined by an esophageal balloon catheter (45); The ventilation controller (180) is further configured to automatically control an esophageal balloon control system (400) and / or to receive control signals from the esophageal balloon control system (400) that automatically control the ventilation controller (180).

1. A ventilation controller (180).

52. configured to bidirectionally interact with the esophageal balloon control system (400) of the esophageal balloon catheter (45); 52. The ventilation controller (180) of claim 51.

53. a pressure determination system (300) configured to determine a transpulmonary pressure (Ptp) based on an esophageal balloon catheter (45) insertable into an esophagus (34), the pressure determination system (300) including a balloon probe (46) for determining an esophageal balloon pressure (Pso); 52. The ventilation controller (180) of claim 51.

54. The transpulmonary pressure (Ptp) is the transpulmonary pressure at the end of the expiratory phase (Ptp_ee) and / or the transpulmonary pressure at the end of the inspiratory phase (Ptp_ei), 54. The ventilation controller (180) of claim 53.

55. configured to set / control / adjust predetermined ventilation parameters (192A, 192B, 192C, 192D) and / or ventilation modes (190A, 190B, 190C, 190D) according to an esophageal balloon control signal provided by said esophageal balloon control system (400); 52. The ventilation controller (180) of claim 51.

56. The device (15) according to any one of claims 1 to 40.

52. The ventilation controller (180) of claim 51.

57. A ventilation device (10) comprising a ventilation controller (180) according to any one of claims 51 to 55.

58. A ventilation device (10) having a ventilation controller (180) as described in claim 56.

59. A method for automatically setting predetermined ventilation parameters (192A, 192B, 192C, 192D) by a ventilation device (10) and / or for automatically displaying information related to mechanical ventilation, comprising: - determining the transpulmonary pressure (Ptb) by means of a pressure determination system (300) based on an esophageal balloon catheter (45) insertable into the esophagus (34) and including a balloon probe (46) for determining the esophageal balloon pressure (Peso); - automatically monitoring and / or setting the operational filling of the balloon probe (46) of the esophageal balloon catheter (45) in vivo by an esophageal balloon control system (400); - setting by a ventilation controller (180) the ventilation parameters (192A, 192B, 192C, 192D) specified by the ventilation device (10) and / or displaying by the ventilation controller (180) information relating to mechanical ventilation based on the transpulmonary pressure (Ptp) determined by the pressure determination system (300); Including, the ventilation controller (180) is further configured to automatically control the esophageal balloon control system (400) and / or the esophageal balloon control system (400) is further configured to automatically control the ventilation controller (180). A method comprising:

60. The ventilation parameter (192A, 192B, 192C, 192D) is a pressure.

60. The method of claim 59.

61. The pressure is positive end-expiratory pressure (PEEP) and / or maximum airway pressure (Paw_max).

61. The method of claim 60.

62. The information regarding the mechanical ventilation is transpulmonary pressure (Ptp).

60. The method of claim 59.

63. The transpulmonary pressure (Ptp) is the transpulmonary pressure at the end of the expiratory phase (Ptp_ee) and / or the transpulmonary pressure at the end of the inspiratory phase (Ptp_ei), 60. The method of claim 59.

64. - automatic control of the esophageal balloon control system (400) by the ventilation controller (180), and / or - automatic control of the ventilation controller (180) by the esophageal balloon control system (400); Including, 60. The method of claim 59.

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