Fluid-conducting device for introducing fluid into and / or removing fluid from an oesophageal balloon catheter

Abstract

The invention relates to a fluid-conducting device (65) for introducing fluid into and / or removing fluid from an oesophageal catheter (48) which can be inserted into an oesophagus (34) and has a balloon probe (46) for determining an oesophageal balloon pressure, comprising: a measuring fluid port (90), which is designed to be coupled to a distal end (48b) of the oesophageal catheter (48) such that, in the coupled state, fluid can be introduced into the oesophageal catheter (48) via the measuring fluid port (90) and / or can be removed from the oesophageal catheter (48); a pump device (100) having at least one fluid pump (102), wherein the pump device (100) is designed to conduct fluid in at least one first conducting direction; and a switching valve (106), which is associated with the at least one fluid pump (102) and can be switched at least between a first position and a second position. The at least one fluid pump (102) is in the form of a micropump or diaphragm pump.

Description

[0001] Fluid delivery device for introducing and / or removing fluid into or from an esophageal balloon catheter

[0002] The present invention relates to a fluid delivery device for introducing and / or withdrawing fluid, in particular measuring fluid, into or from an esophageal balloon catheter with a balloon probe that can be inserted into an esophagus. The invention also relates to a device for determining esophageal balloon pressure using a fluid delivery device according to the invention, and to a ventilation device comprising such a device for determining esophageal balloon pressure.

[0003] Catheters with balloon probes for determining esophageal balloon pressure ("esophageal balloon catheters") are used particularly during mechanical ventilation to determine the transpulmonary pressure in a patient's chest.

[0004] In today's common forms of mechanical ventilation, breathing gas is supplied to the patient at positive pressure. Therefore, during ventilation, the airway pressure or alveolar pressure is greater than the pressure in the pleural space surrounding the alveoli, at least during the inspiration phase. During the expiration phase, the ventilation device does not pressurize the airway, with the result that the lung tissue relaxes and the airway pressure or alveolar pressure drops. Under certain circumstances, this type of positive pressure ventilation can lead to the pressure conditions in the airway or alveoli becoming so unfavorable at the end of the expiration phase that part of the alveoli collapses. The collapsed part of the lung volume then has to be expanded again in the subsequent respiratory cycle.The functional residual capacity of the lungs is severely impaired, so that oxygen saturation decreases, and the lung tissue also suffers permanent damage.

[0005] To prevent alveolar collapse at the end of the expiratory phase, mechanical positive pressure ventilation typically uses a so-called positive end-expiratory pressure, commonly referred to as PEEP. This measure can often improve oxygen saturation. During PEEP ventilation, the ventilator continuously applies a predetermined positive pressure, the PEER, to the airway—both during the inspiration and expiration phases. PEEP therefore remains in effect even after the end of the expiration phase.

[0006] Ideally, PEEP should be set sufficiently high so that during the expiratory phase, the alveolar pressure is not below the pressure in the pleural space, or at least only so far below that the alveolar tissue does not collapse under the influence of the pressure in the pleural space. In other words, PEEP should prevent the transpulmonary pressure—the pressure difference between alveolar pressure and pressure in the pleural space—from falling below zero or below a lower negative limit at which parts of the alveoli begin to collapse.

[0007] On the other hand, too high a PEEP value can have negative effects, especially during the inspiration phase. This is because lung tissue can become over-expanded at very high airway pressures during the inspiration phase. Numerous studies also indicate that a high PEEP value can impede the return of venous blood to the heart, with correspondingly negative effects on the cardiovascular system.

[0008] In principle, PEEP should be adjusted to the prevailing transpulmonary pressure. However, the transpulmonary pressure in a ventilated patient is not easily determined. Therefore, the pressure is measured in a balloon probe, which is placed in the esophagus of a ventilated patient using an esophageal balloon catheter. With appropriate positioning and configuration of the balloon, the pressure measured in the balloon can be used to approximately determine the pressure in the pleural space.

[0009] WO 2014 / 037175 A1 describes an automated adjustment of a pressure specified by a ventilation device, in particular the positive end-expiratory pressure (PEEP) and the maximum airway pressure, based on the esophageal balloon pressure, which is considered an indicator of the transpulmonary pressure, i.e., the pressure difference between alveolar pressure and pleural pressure. In practice, it can happen that the relationship between the pressure measured in a balloon catheter inserted into the esophagus and the pleural pressure changes during ventilation. The reasons for this can be manifold and are generally not identifiable in detail.

[0010] Mojoli et al., Crit. Care (2016) 20:98 and Hotz et al., Respir. Care (2018) 63(2): 177-186 recommend procedures for calibrating an esophageal balloon catheter with a balloon probe. The goal of calibration is to achieve optimal inflation of the balloon probe with air, with the balloon probe responding as sensitively as possible to changes in the pleural pressure acting on the esophagus and reflecting the pleural pressure as accurately as possible.

[0011] However, the calibration measurement procedures described by Mojoli et al. are complex and sensitive, so that in practice, only an optimal inflation rate for the balloon probe can be determined and preset before the start of ventilation. This optimal inflation rate is then maintained during ventilation and cannot be changed.

[0012] There is therefore a need to enable a simpler and more accurate determination of esophageal balloon pressure using an esophageal balloon catheter, particularly as a basis for determining pleural space pressure for determining transpulmonary pressure during mechanical ventilation. Furthermore, a largely automatic calibration of a system for determining esophageal balloon pressure as a surrogate for pleural space pressure should be enabled.

[0013] For the operation and calibration of an esophageal balloon catheter during ventilation, in addition to sufficiently accurate pressure measurement, the control of the amount of measuring fluid in the esophageal balloon catheter must also be taken into account.

[0014] EP 3 197 348 B1 proposes the use of a syringe pump known in the medical field as a fluid delivery device for filling and emptying an esophageal balloon catheter.

[0015] The present invention solves the problem of providing an improved fluid delivery device for filling and emptying an esophageal balloon catheter that operates reliably and is cost-effective. The invention comprises a fluid delivery device for introducing and / or removing fluid into or from a catheter insertable into an esophagus with a balloon probe ("esophageal balloon catheter") for determining esophageal balloon pressure, wherein the fluid delivery device comprises: a measuring fluid connection for connection to an esophageal balloon catheter, a pumping device with at least one fluid pump designed to deliver fluid in at least a first delivery direction, and a switching valve associated with the fluid pump.

[0016] The esophageal balloon catheter is referred to simply as "catheter" in the following.

[0017] The measuring fluid port is designed for coupling to a distal end of a catheter such that, in the coupled state, fluid can be introduced into the catheter via the measuring fluid port and / or removed from the catheter. The switching valve can be switched at least between a first position and a second position. The fluid pump can be designed as a diaphragm pump or as a micropump, in particular as a piezo pump.

[0018] Micropumps and diaphragm pumps operate quickly and precisely, particularly when frequent changes occur between introducing fluid into the catheter and withdrawing fluid from the catheter. Both micropumps and diaphragm pumps have a low number of components. In particular, both types of fluid pumps contain only a few components susceptible to wear. Both types of fluid pumps are therefore durable and inexpensive to manufacture. Micropumps allow for a particularly compact design, allowing them to be used even in confined spaces. Diaphragm pumps and micropumps according to the invention are very quiet in operation. Their design is also less complex than that of syringe pumps; in particular, they comprise fewer moving elements. This makes them more reliable and less maintenance-prone than syringe pumps. Diaphragm pumps can generally achieve higher mass flows than micropumps.In the following, the term "feed direction" refers to the flow direction of the measuring fluid delivered by the fluid pump in relation to the catheter.

[0019] The "feed direction" defined in this way must be distinguished from the flow direction of the measuring fluid through the fluid pump itself. Since the flow direction of the measuring fluid through the fluid pump itself is irreversible, i.e., the flow direction within the fluid pump is fixed, the fluid pump always feeds the fluid from an inlet of the fluid pump to an outlet of the fluid pump. The feed direction, i.e., the flow direction of the measuring fluid with respect to the catheter, therefore results from the fact that the measuring fluid connection is connected, in particular via the switching valve, either to the inlet or to the outlet of the fluid pump.

[0020] If the fluid pump outlet is connected to the measurement fluid port, the first flow direction of the fluid pump corresponds to the introduction of fluid into the catheter. If the fluid pump inlet is connected to the measurement fluid port, the first flow direction of the fluid pump corresponds to the withdrawal of fluid from the catheter.

[0021] In the following, the terms "inlet" and "outlet" of the fluid pump always refer to the flow direction of fluid through the respective fluid pump itself and not to the flow direction, which can be switched by the changeover valve.

[0022] A fluid conveying device according to the invention can comprise a first fluid pump and a second fluid pump. The first fluid pump can be designed and arranged to convey fluid in a first conveying direction, and the second fluid pump can be designed and arranged to convey fluid in a second conveying direction.

[0023] The first conveying direction can, in particular, be opposite to the second conveying direction. Thus, the first conveying direction can correspond to the introduction of fluid into the catheter, and the second conveying direction can correspond to the removal of fluid from the catheter, or vice versa.

[0024] In the fluid delivery device with at least two fluid pumps, the introduction of fluid into the catheter and the removal of fluid from the catheter are handled by two different fluid pumps. For example, the introduction of fluid into the catheter is handled by the first fluid pump, and the removal of fluid from the catheter is handled by the second fluid pump, or vice versa. With such a design, each fluid pump can be optimized for its respective delivery direction. Only a single switching valve is required to switch the delivery direction of the fluid delivery device between the introduction and removal of fluid.

[0025] The first and second fluid pumps can be arranged and connected in parallel. "Connected in parallel" in this context means that, depending on the position of the switching valve, either an output of the first fluid pump is connected to the measuring fluid connection or an input of the second fluid pump is connected to the measuring fluid connection. The switching valve is thus designed to connect the measuring fluid connection either to the output of the first fluid pump or to the input of the second fluid pump.

[0026] The switching valve is arranged in particular between the outlet of the first fluid pump and the measuring fluid connection and between the inlet of the second fluid pump and the measuring fluid connection.

[0027] The second fluid pump can also be designed as a micropump or a diaphragm pump. The first fluid pump and the second fluid pump can both be designed as micropumps or both as diaphragm pumps, so that both fluid pumps have similar or even essentially identical operating characteristics. In particular, the first fluid pump and the second fluid pump can be constructed identically.

[0028] If different operating characteristics, in particular pressures and / or delivery lines, are desired for introducing fluid into the catheter and for removing fluid from the catheter, the first fluid pump and the second fluid pump can also be designed differently so that they have different operating characteristics.

[0029] The first and / or the second fluid pump can in particular be designed such that they are capable of generating a maximum fluid pressure in a range from 50 hPa to 150 hPa, in particular a maximum fluid pressure in a range from 80 hPa to 100 hPa, and provide a flow rate in a range from 60 ml / min to 200 ml / min, in particular a flow rate in a range from 70 ml / min to 100 ml / min.

[0030] Fluid pumps designed as piezo pumps can be operated in a fluid conveying device according to the invention at a frequency in a range between 100 Hz and 1500 Hz, in particular at a frequency in a range between 800 Hz and 1000 Hz. To achieve the desired delivery rate, the fluid pumps can be operated, in particular, at a higher frequency than specified by the respective manufacturer's specifications.

[0031] The switching valve can be switched between at least one first and at least one second opening position. When the switching valve is switched to the first opening position, the output of the first fluid pump can be fluidically connected to the measuring fluid connection, and the input of the second fluid pump can be fluidically separated from the measuring fluid connection. When the switching valve is switched to the second opening position, the input of the second fluid pump can be fluidically connected to the measuring fluid connection, and the output of the first fluid pump can be fluidically separated from the measuring fluid connection.

[0032] In this context, "fluidically connected" means that a fluid connection exists between the measuring fluid port and the first or second fluid pump, respectively, so that fluid can be pumped from the first or second fluid pump to the measuring fluid port. "Fluidically separated" means in this context that there is no fluid connection between the measuring fluid port and the first or second fluid pump, respectively, so that no fluid can be pumped from the first or second fluid pump to the measuring fluid port.

[0033] In a fluid delivery device designed in this way, the first fluid pump delivers fluid into the catheter (introducing fluid) when the switching valve is in the first open position, and the second fluid pump delivers fluid out of the catheter (removing fluid) when the switching valve is in the second open position. The switching valve can comprise a first release valve assigned to the first fluid pump and a second release valve assigned to the second fluid pump. The first release valve can be switchable at least between an open position in which the outlet of the first fluid pump is fluidically connected to the measuring fluid connection, and a closed position in which the outlet of the first fluid pump is fluidically separated from the measuring fluid connection.The second release valve can be switchable at least between an open position in which the inlet of the second fluid pump is fluidically connected to the measuring fluid connection, and a closed position in which the inlet of the second fluid pump is fluidically separated from the measuring fluid connection.

[0034] The first and the second release valve can in particular be arranged parallel to each other, so that fluid can flow through the switching valve when at least one of the two release valves is in its open position.

[0035] In this way, the function of the changeover valve can be realized cost-effectively and reliably by two release valves, which are simple valves, each having only one open position and one closed position.

[0036] The changeover valve and in particular the release valves can be designed as mechanically, electrically, hydraulically and / or pneumatically controllable valves.

[0037] The first and second release valves can be coordinated or synchronized with each other such that they can only be switched together, so that when the first release valve is in the open position, the second release valve is in the closed position, and when the first release valve is in the closed position, the second release valve is in the open position. This ensures that one of the two release valves is open and closed at any given time. This reliably prevents a malfunction of the switching valve, in which both release valves are open or closed at the same time.

[0038] The release valves can be mechanically, electrically, hydraulically, and / or pneumatically coordinated or synchronized with one another. The switching valve can also be designed such that it fluidically connects the measuring fluid connection either to an inlet of the (first) fluid pump or to an outlet of the (first) fluid pump. With a switching valve designed in this way, a fluid delivery device can be created that has only a single fluid pump and that can be switched between two opposing delivery directions, in particular a first delivery direction for introducing fluid into a catheter and a second delivery direction for removing fluid from a catheter.

[0039] A second fluid pump can be dispensed with in such a fluid conveying device, whereby the costs of the fluid conveying device can be kept low.

[0040] The omission of a second fluid pump is particularly advantageous when a diaphragm pump is used as the fluid pump, since diaphragm pumps are generally more expensive than micropumps and require a larger installation space.

[0041] A fluid conveying device which has a switching valve which is designed in such a way that it fluidically connects the measuring fluid connection optionally to an inlet of a fluid pump or to an outlet of the fluid pump can also be equipped with at least one further fluid pump.

[0042] For example, a second fluid pump can be connected in series with the first fluid pump to increase the maximum achievable fluid output pressure. By connecting at least two fluid pumps in parallel, the maximum achievable fluid flow can be increased.

[0043] Such a series or parallel connection works with both diaphragm pumps and micropumps / piezo fluid pumps. A parallel or series connection of at least two fluid pumps is particularly advantageous when micropumps / piezo pumps are used as fluid pumps, since these often have a lower flow rate than diaphragm pumps; in particular, a flow rate that is lower than the flow rate desired for introducing and / or removing fluid into or from a catheter. The switching valve can comprise a combination of several switching valves. The switching valve can, in particular, comprise a first flow direction switching valve and a second flow direction switching valve, wherein the first flow direction switching valve and the second flow direction switching valve are arranged in series with one another with respect to the flow direction of fluid through the fluid pump.In this context, "arranged in series" means that the first and second flow direction switching valves are arranged one behind the other in the flow direction of the measuring fluid, and that no fluid could be pumped by the fluid pump if (hypothetically) at least one of the two flow direction switching valves were in a blocking position in which it blocked the flow of fluid.

[0044] The first flow direction switching valve can be arranged downstream of the fluid pump with respect to the direction of flow of fluid through the fluid pump. The second flow direction switching valve can be arranged upstream of the fluid pump with respect to the direction of flow of fluid through the fluid pump.

[0045] The flow direction switching valve can be assigned to the outlet of the fluid pump or arranged adjacent to it and fluidically connected to the outlet of the fluid pump. Accordingly, the second flow direction switching valve can be assigned to the inlet of the fluid pump or arranged adjacent to it and fluidically connected to the inlet of the fluid pump.

[0046] The first conveying direction switching valve can be switchable between at least one first opening position and at least one second opening position, wherein in the first opening position the outlet of the fluid pump is fluidically connected to the measuring fluid connection and in the second opening position the outlet of the fluid pump is fluidically separated from the measuring fluid connection.

[0047] Similarly, the second flow direction switching valve can be switchable between at least one first and one second opening position, wherein in the first opening position, the inlet of the fluid pump is fluidically separated from the measuring fluid connection, and in the second opening position, the inlet of the fluid pump is fluidically connected to the measuring fluid connection. In this way, a fluid delivery device can be realized with a single fluid pump, which allows the fluid delivery direction of the fluid delivery device to be switched in a targeted manner. The costs and installation space for a second fluid pump can be saved in this way.

[0048] The first and second flow direction switching valves can be coupled to one another in such a way that they can only be switched in a coordinated or synchronized manner, in particular such that when the first flow direction switching valve is in the first open position, the second flow direction switching valve is also in the first open position. This can correspond to an operating state in which the operation of the fluid pump leads to the introduction of fluid into the catheter.

[0049] The first and second flow direction switching valves can be coupled to one another in such a way that they can only be switched in a coordinated or synchronized manner, in particular such that when the first flow direction switching valve is in the second open position, the second flow direction switching valve is also in the second open position. This can correspond to an operating state in which the operation of the fluid pump leads to the removal of fluid from the catheter.

[0050] By coupling the conveying direction switching valves in this way, a combination of opening positions of the two conveying direction switching valves that does not correspond to a desired operating state of the fluid conveying device can be reliably avoided.

[0051] The first and second flow direction changeover valves can be actuated mechanically, electrically, pneumatically and / or hydraulically.

[0052] The first and the second conveying direction switching valve can be coupled to each other in particular mechanically, electrically, pneumatically and / or hydraulically.

[0053] By selectively, if necessary temporarily, removing the coupling between the flow direction switching valves, special operating states can be set if required, in which the two flow direction switching valves are in different opening positions and in which fluid is neither pumped into the catheter nor removed from the catheter.

[0054] Such special operating states can be set, for example, to bring the delivery capacity of the fluid pump into a defined state, e.g. after starting up the fluid pump, before fluid is delivered from the fluid pump into the catheter, and / or to deliver fluid in a circuit, e.g. to flush the components of the fluid delivery device with fluid.

[0055] The fluid conveying device can also have a valve with a blocking function that allows the pumping device to be fluidically separated from the measuring fluid connection so that no fluid can flow between the pumping device and the measuring fluid connection.

[0056] The fluid conveying device can in particular have a blocking valve which is arranged downstream of the fluid pump and which has at least one blocking position in which the pumping device is separated from the measuring fluid connection.

[0057] The blocking valve can be a valve formed separately from the switching valve. Such a separately formed blocking valve can be arranged downstream in series with the switching valve; in particular, it can be arranged between the switching valve and the measuring fluid connection in order to be able to fluidically separate the measuring fluid connection, and in particular a catheter connected to the measuring fluid connection, from the fluid pump.

[0058] A switching valve can also be used that has a blocking position in which the pumping device is fluidically separated from the measuring fluid connection. In this case, a separate switching valve is not necessary.

[0059] Each fluid pump can be assigned a device for creating a flow resistance, in particular a constriction of the flow cross-section. Such a device can in particular be designed such that it reduces the fluid flow achievable at maximum pumping power of the respective fluid pump to a predetermined value through its flow resistance. This can prevent damage to a catheter connected to the fluid delivery device and / or falsification of measurement results due to excessive fluid flow. The use of a device for creating a flow resistance is particularly advantageous when at least one diaphragm pump is used as the fluid pump, since diaphragm pumps generally have a higher nominal flow rate than micropumps / piezo fluid pumps.In particular, diaphragm pumps often have a nominal flow rate that is greater than that required for filling and emptying catheters in the context described here.

[0060] Using a device to create a flow resistance, the delivered fluid volume can be reduced to a flow rate suitable for the catheter without having to change the rated flow rate of the fluid pump. The fluid pump can thus continue to operate within its optimal operating range.

[0061] The device for forming a flow resistance can be arranged in series with the respective fluid pump in the flow direction. The device for forming a flow resistance can be arranged, in particular, upstream at the inlet and / or downstream at the outlet of the respective fluid pump.

[0062] If the fluid conveying device has more than one fluid pump, a common device for forming a flow resistance can be provided, which is assigned to several, in particular all, fluid pumps. A separate device for forming a flow resistance can also be provided for each fluid pump.

[0063] Such devices may, for example, be arranged downstream of the outlet of the first fluid pump and upstream of the inlet of the second fluid pump and / or upstream of the inlet of the first fluid pump and downstream of the outlet of the second fluid pump.

[0064] A first device for forming a flow resistance can be arranged, in particular, between the outlet of the first fluid pump and the measuring fluid connection. A second device for forming a flow resistance can be arranged, in particular, between the inlet of the second fluid pump and the measuring fluid connection. In this case, the first and second devices for forming a flow resistance are arranged parallel to one another.

[0065] A common device for forming a flow resistance can be arranged such that, depending on the position of the changeover valve, it is arranged between the outlet of the first fluid pump and the measuring fluid connection or between the inlet of the second fluid pump and the measuring fluid connection.

[0066] Instead of or in addition to at least one device for forming a flow resistance, at least one bypass can also be provided, which guides a part of the fluid conveyed by the at least one fluid pump past the catheter in order to reduce the amount of fluid conveyed into the catheter and / or the fluid pressure in the catheter.

[0067] A fluid conveying device according to the invention may further comprise a flow sensor designed to detect the fluid flow conveyed by the first and / or the second fluid pump into or out of the catheter.

[0068] The flow sensor can be designed, in particular, to detect a mass flow of fluid conveyed into or out of the catheter or to detect a volume flow of fluid conveyed into or out of the catheter. For this purpose, the flow sensor can be arranged, in particular, between the measuring fluid connection and the at least one fluid pump.

[0069] A fluid delivery device according to the invention can also comprise a pressure sensor designed to measure a fluid pressure. The pressure sensor can, in particular, be designed to measure the fluid pressure in a region of a fluid delivery line between the measuring fluid connection and the first or second fluid pump.

[0070] The invention also encompasses a device for detecting esophageal balloon pressure based on a catheter with a balloon probe that can be inserted into an esophagus ("esophageal balloon catheter"), wherein the device comprises a fluid delivery device according to the invention. The invention also encompasses a ventilation device comprising such a device for detecting esophageal balloon pressure with a fluid delivery device according to the invention. The ventilation device can be designed, in particular, for automatically determining a transpulmonary pressure based on the measured esophageal balloon pressure.

[0071] In the following, the previously described and further embodiments of the invention are described in more detail with reference to the attached figures.

[0072] Figure 1 shows a schematic representation of an esophageal balloon catheter that can be inserted into the esophagus of a patient and a system for characterizing the esophageal balloon catheter, which comprises a fluid delivery device according to the invention.

[0073] Figure 2 shows a schematic view of a fluid conveying device according to a first embodiment of the invention.

[0074] Figure 3 shows a schematic view of a fluid conveying device according to a second embodiment of the invention.

[0075] Figure 4A shows a fluid conveying device designed according to a third embodiment of the invention in a first operating state.

[0076] Figure 4B shows a fluid conveying device designed according to a third embodiment of the invention in a second operating state.

[0077] Figure 5 shows, in a schematic representation, the essential elements of a ventilation device according to the invention with a system for characterizing an esophageal balloon catheter, which comprises a fluid conveying device according to the invention.

[0078] Figure 1 shows a simplified schematic representation of an esophageal balloon catheter 48, hereinafter referred to as "catheter 48," and a device 60 for detecting esophageal balloon pressure. The catheter 48 comprises a catheter tube 47 insertable into an esophagus (food pipe) 34 (see Figure 5) of a patient.

[0079] A balloon probe 46 is located at a first, proximal end 48a of the catheter tube 47.

[0080] A second, distal end 48b of the catheter tube 47 is connected to a measuring fluid port 90 of the device 60 for detecting the esophageal balloon pressure such that the catheter 48 can be pressurized, in particular filled, with a fluid, in particular air, by the device 60. The device 60 for detecting the esophageal balloon pressure is also capable of withdrawing fluid from the catheter 48 through the measuring fluid port 90 in order to empty the catheter 48, in particular the balloon probe 46 of the catheter 48.

[0081] The measuring fluid connection 90 on the device 60 can, for example, be a male Lyer-Lock connection or a hose connector that is compatible with a Lyer-Lock connection, so that both plastic hoses and Lure plugs can be plugged onto the measuring fluid connection 90.

[0082] The fluid connection between the second, distal end 48b of the catheter tube 47 and the device 60 for detecting the esophageal balloon pressure at the measuring fluid connection 90 is detachable, so that the catheter 48 can be selectively connected to and separated from the device 60 for detecting the esophageal balloon pressure.

[0083] The device 60 for detecting the esophageal balloon pressure comprises a fluid delivery device 65, which is designed to selectively introduce fluid into the catheter 48 and to withdraw fluid from the catheter 48. The fluid delivery device 65 is in fluid communication with the catheter tube 47 at the measuring fluid port 90 and, in particular, comprises a pump device 100 and at least one valve 107.

[0084] The device 60 for detecting the esophageal balloon pressure further comprises a flow sensor 62, in particular a mass flow sensor 62, which is designed to determine the amount, ie the volume and / or mass flow, of fluid introduced into the catheter 48 and / or the amount of fluid removed from the catheter 48, and a pressure sensor 63, which is designed to determine the fluid pressure in the catheter 48.

[0085] The flow sensor 62, the pressure sensor 63 and the valve 107 can each be formed as a component of the fluid delivery device 65 (as shown in Figure 1), or as separate elements of the device 60 for detecting the esophageal balloon pressure, ie separate from the fluid delivery device 65.

[0086] The device 60 for detecting the esophageal balloon pressure also includes at least one controller 80 configured to determine the esophageal balloon pressure. Such a method includes, in particular, appropriately controlling the fluid delivery device 65 to selectively fill the catheter 48 with fluid and / or remove fluid from the catheter 48.

[0087] The at least one controller 80 can be implemented as a standalone component in hardware. Two or more controllers 80 can also be integrated into a common component or into a common group of components. The at least one controller 80 can also be integrated into a ventilator 10 (see Figure 5).

[0088] The at least one controller 80 can also be implemented 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 can be stored on a suitable local storage medium or on a network-accessible storage medium. The software contains instructions encoded as a computer program which, when the software is loaded into a working memory of the processor and translated into machine language, cause the processor to execute the procedures described in more detail herein. Mixed forms between a hardware implementation and a software implementation are also possible.

[0089] The controller 80 can be configured to allow a catheter 48 to be filled with a defined amount of fluid in order to operate the catheter 48 in vivo, i.e., in the esophagus 34 of a patient, to measure the esophageal balloon pressure in the patient's esophagus 34 and, therefrom, to determine the transpulmonary pressure in the patient's chest. The controller 80 can also be configured to operate the device 60 for detecting the esophageal balloon pressure as a characterization system designed to characterize and, if necessary, classify the catheter 48 ex vivo, i.e., before it is introduced into the esophagus 34 of a patient.

[0090] The device 60 also has a storage device 70 which is designed to store at least one detected variable, e.g. the balloon pressure and / or a characteristic property or parameter of the catheter 48, which has been determined by the device 60, and to output it as needed via an output device 72, e.g. an electronic interface, a display device ("screen") and / or a printer.

[0091] Figure 2 shows a schematic view of a fluid conveying device 65 which is designed according to a first embodiment of the invention.

[0092] The fluid conveying device 65 comprises a pumping device 100 with a first fluid pump 102 and a second fluid pump 104. The two fluid pumps 102, 104 can be designed in particular as micropumps 102, 104, for example as piezo pumps 102, 104.

[0093] Such micropumps / piezo pumps 102, 104 have a particularly compact design and are available at low cost.

[0094] The two fluid pumps 102, 104 are designed such that they each have a predetermined flow direction R1 or R2 in which the fluid is pumped by the respective fluid pump 102, 104.

[0095] Each fluid pump 102, 104 therefore has a fluid inlet 102a, 104a through which the pumped fluid flows into the respective fluid pump 102, 104 during operation, and a fluid outlet 102b, 104b through which the fluid leaves the respective fluid pump 102, 104 during operation.

[0096] The fluid pumps 102, 104 are connected to a switching valve 106 such that their flow directions R1, R2 are opposite to each other. That is, the fluid outlet 102b of the first fluid pump 102 and the fluid inlet 104a of the second fluid pump 104 are connected to the switching valve 106.

[0097] The fluid inlet 102a of the first fluid pump 102 is fluidly connected to the environment via an inlet line 110a, and the fluid outlet 104b of the second fluid pump 104 is fluidly connected to the environment via an outlet line 110b. Thus, the fluid pumps 102, 104 can draw in air as fluid from the environment through the inlet line 110a and discharge fluid into the environment through the outlet line 110b.

[0098] The inlet line 110a and the outlet line 110b can optionally be combined to form a common inlet and outlet line 110.

[0099] If a fluid other than air is to be used as the fluid, the supply line 110a can be fluidically connected to a corresponding fluid source, not shown in the figures, which provides the desired fluid, e.g. oxygen-enriched air.

[0100] The side of the switching valve 106 facing away from the fluid pumps 102, 104, shown at the bottom in Figure 2, is fluidically connected to a fluid delivery line 108. By switching the switching valve 106, either the first fluid pump 102 or the second fluid pump 104 can be fluidically connected to the fluid delivery line 108.

[0101] A blocking valve 107 can optionally be provided in the fluid delivery line 108, which is designed to block any fluid flow through the fluid delivery line 108 in a blocking position and to allow fluid flow through the fluid delivery line 108 in a release position.

[0102] The switching valve 106 can also be designed such that it additionally has a blocking position in which neither the first fluid pump 102 nor the second fluid pump 104 is connected to the fluid delivery line 108 and any fluid flow through the fluid delivery line 108 is blocked by the switching valve 106. In this case, a separate blocking valve 107 can be dispensed with. On the side of the blocking valve 107 facing away from the switching valve 106, a flow sensor 62 and a pressure sensor 63 are provided. The flow sensor 62 is designed to measure the fluid flow through the fluid delivery line 108, and the pressure sensor 63 is designed to measure the fluid pressure in the fluid delivery line 108.

[0103] On the side of the sensors 62, 63 facing away from the valves 106, 107 there is the measuring fluid connection 90, which makes it possible to fluidically connect the catheter tube 47 of the catheter 48 to the fluid delivery line 108.

[0104] When the catheter tube 47 of a catheter 48 is fluidically connected to the measuring fluid connection 90, the blocking valve 107 is open and the switching valve 106 is in a first position, as shown in Figure 2, fluid can be pumped by the first fluid pump 102 from the inlet line 110a into the catheter 48.

[0105] When the switching valve 106 is in a second position, which is not shown in Figure 2, fluid can be withdrawn from the catheter 48 and discharged into the drain line 110b by the operation of the second fluid pump 104.

[0106] The switching valve 106 may in particular comprise a first release valve 106a assigned to the first fluid pump 102 and a second release valve 106b assigned to the second fluid pump 104.

[0107] In such a configuration, the first release valve 106a can be switchable at least between an open position in which the fluid outlet 102b of the first fluid pump 102 is fluidically connected to the fluid delivery line 108, and a closed position in which the fluid outlet 102b of the first fluid pump 102 is fluidically separated from the fluid delivery line 108.

[0108] Analogously, the second release valve 106b can be switchable at least between an open position, in which the fluid inlet 104a of the second fluid pump 104 is fluidically connected to that of the fluid delivery line 108, and a closed position, in which the fluid inlet 104a of the second fluid pump 104 is fluidically separated from the fluid delivery line 108. In such a configuration, in which the switching valve 106 is designed with two release valves 106a, 106b, the previously described function of the switching valve 106, to switch the delivery direction of the fluid delivery device 65, can be realized by specifically opening and closing the two release valves 106a, 106b.

[0109] The two release valves 106a, 106b can in particular be arranged parallel to one another, so that the opening or release of one of the two release valves 106a, 106b is sufficient to allow fluid to flow through the switching valve 106.

[0110] The switching valve 106 and in particular the two release valves 106a, 106b can be designed as mechanically, electrically, hydraulically and / or pneumatically controllable valves.

[0111] The first and second release valves 106a, 106b can be mechanically, hydraulically, pneumatically and / or electrically coordinated or synchronized with one another such that when the first release valve 106a is in its open position, the second release valve 106b is in its closed position, and when the first release valve 106a is in its closed position, the second release valve 106b is in its open position.

[0112] In this way, it can be ensured that the switching valve can be switched (only) between two well-defined operating states in which one of the release valves 106a, 106b is open and the other of the release valves 106a, 106b is closed.

[0113] The pumping device 100 can also be configured such that the first fluid pump 102 can pump against a closed blocking valve 107 in order to adjust the system pressure at the fluid outlet 102b to the pressure in the esophageal balloon catheter 48, instead of pumping fluid into the environment to bring the first fluid pump 102 to the desired delivery rate. In this case, the pressure sensor 63 or an additional pressure sensor, not shown in Figure 2, would have to be provided between the fluid pump 102 and the blocking valve 107 in order to measure the fluid pressure at the fluid outlet 102b of the first fluid pump 102 and adjust it to the desired value. Figure 3 shows a schematic view of a fluid delivery device 65 configured according to a second embodiment of the invention.

[0114] The structure of the fluid conveying device 65 shown in Figure 3, which is designed according to the second exemplary embodiment of the invention, essentially corresponds to the structure of the fluid conveying device 65, which is designed according to the first exemplary embodiment shown in Figure 2. The features of the second exemplary embodiment that correspond to features of the first exemplary embodiment are provided with the same reference numerals and, to avoid repetition, will not be described again in detail. Instead, reference is made to the description of the first exemplary embodiment.

[0115] The fluid conveying device 65 according to the second embodiment differs from the fluid conveying device 65 according to the first embodiment in that in the fluid conveying device 65 according to the second embodiment, a device 105a, 105b for forming a flow resistance is provided between the first fluid pump 102 and the switching valve 106 and between the second fluid pump 104 and the switching valve 106, which device is designed to reduce or limit a measuring fluid flow to a predetermined value at maximum pumping power of the first fluid pump 102 and / or the second fluid pump 104.

[0116] A device 105a, 105b for forming a flow resistance can, in particular, comprise a constriction of the flow cross-section, e.g., in the form of an orifice or throttle. Alternatively or additionally, the device 105a, 105b for forming a flow resistance can comprise a porous material, e.g., a foam, that is introduced into the flow path of the fluid in order to reduce or limit the flow of the measuring fluid.

[0117] The provision of such devices 105a, 105b for forming a flow resistance is particularly useful when the nominal delivery rates of the fluid pumps 102, 104 are greater than is required for the intended introduction and / or removal of fluid from the catheter 48 and there is a risk that the catheter 48 will be damaged by the fluid flow achievable at the maximum delivery rate of the fluid pumps 102, 104 and / or that a desired procedure cannot be carried out properly due to the high pressure and / or due to the high fluid flow.

[0118] The provision of a device 105a, 105b for forming a flow resistance also enables a more precise adjustment of the flow rate, since the fluid pump 102, 104 does not have to be operated in a range with a very low delivery rate, but can be operated in a higher range in which the flow rate of the fluid pump 102, 104 can be better adjusted.

[0119] This can occur in particular if at least one of the fluid pumps 102, 104 is designed as a diaphragm pump, since diaphragm pumps generally have a higher nominal flow rate than micropumps / piezo pumps.

[0120] In the embodiment shown in Figure 3, the devices 105a, 105b for forming a flow resistance are arranged between the fluid pumps 102, 104, which are designed in particular as diaphragm pumps, and the switching valve 106. The devices 105a, 105b for forming a flow resistance are thus arranged downstream of the fluid outlet 102b of the first fluid pump 102 and upstream of the fluid inlet 104a of the second fluid pump 104.

[0121] In alternative embodiments, which are not explicitly shown in the figures, at least one of the devices 105a, 105b for forming a flow resistance can also be arranged on the "other side" of the respective fluid pump 102, 104, ie upstream of the respective fluid pump 102, 104, at the fluid inlet 102a of the first fluid pump 102, or downstream, at the fluid outlet 104b of the second fluid pump 104.

[0122] In a further embodiment, not explicitly shown in the figures, a device 105a, 105b common to both fluid pumps 102, 104 can also be provided for forming a flow resistance, through which fluid flows in one or the other direction depending on the position of the switching valve 106.

[0123] Such a common device 105a, 105b for forming a flow resistance can be arranged, for example, in a common supply air and discharge line 110 and / or on the side of the switching valve 106 in the fluid delivery line 108 facing away from the fluid pumps 102, 104, for example between the switching valve 106 and the blocking valve 107 or between the blocking valve 107 and the flow sensor 62.

[0124] Figures 4A and 4B show schematic views of a fluid conveying device 65 constructed according to a third embodiment of the invention. Figures 4A and 4B show the fluid conveying device 65 in two different operating states.

[0125] The pumping device 100 of a fluid conveying device 65, which is designed according to a third exemplary embodiment of the invention, comprises only a single fluid pump 102, which is designed to convey fluid in a predetermined flow direction R1 from a fluid inlet 102a to a fluid outlet 102b of the fluid pump 102.

[0126] In a fluid conveying device 65 designed according to a third exemplary embodiment of the invention, the switching valve 106 comprises a first conveying direction switching valve 106-1 which is fluidically connected to the fluid inlet 102a of the fluid pump 102 so that it is arranged upstream of the fluid pump 102, and a second conveying direction switching valve 106-2 which is fluidically connected to the fluid outlet 102b of the fluid pump 102 so that it is arranged downstream of the fluid pump 102.

[0127] The first conveying direction switching valve 106-1 and the second conveying direction switching valve 106-2 are thus arranged in series with respect to the flow direction R1 of the measuring fluid, so that the two conveying direction switching valves 106-1, 106-2 are arranged one behind the other in the flow direction R1 of the measuring fluid, with the fluid pump 102 being arranged between the two conveying direction switching valves 106-1, 106-2. Such a series arrangement of the two conveying direction switching valves 106-1, 106-2 has the consequence that in a hypothetical case in which at least one of the two conveying direction switching valves 106-1, 106-2 blocks the fluid flow, no fluid could be pumped by the fluid pump 102. The two conveying direction switching valves 106-1, 106-2 can each be switched between at least a first and a second opening position.

[0128] The two conveying direction switching valves 106-1, 106-2 can each comprise a first release valve 106a and a second release valve 106b, as has been described in connection with the first embodiment.

[0129] In Figure 4A, the fluid conveying device 65 is shown in an operating state in which the two conveying direction switching valves 106-1, 106-2 are in the first open position.

[0130] In the first open position of the first conveying direction switching valve 106-1, the fluid inlet 102a of the fluid pump 102 is fluidly connected to the supply line 110a via the first conveying direction switching valve 106-1. In the first open position of the second conveying direction switching valve 106-2, the fluid outlet 102b of the fluid pump 102 is fluidly connected to the fluid conveying line 108 via the second conveying direction switching valve 106-2.

[0131] Figure 4B shows a state in which both conveying direction switching valves 106-1, 106-2 are in the second opening position.

[0132] In the second open position of the first conveying direction switching valve 106a, the fluid inlet 102a of the fluid pump 102 is fluidly connected to the fluid conveying line 108 via the first conveying direction switching valve 106-1. In the second open position of the second conveying direction switching valve 106-2, the fluid outlet 102b of the fluid pump 102 is fluidly connected to the drain line 110b via the second conveying direction switching valve 106-2.

[0133] The first conveying direction switching valve 106-1 and the second conveying direction switching valve 106-2 can be mechanically, hydraulically, pneumatically and / or electrically controllable valves.

[0134] The first conveying direction switching valve 106-1 and the second conveying direction switching valve 106-2 can be coordinated or synchronized with one another, in particular mechanically, hydraulically, pneumatically and / or electrically, such that when the first conveying direction switching valve 106-1 is in the first open position, the second conveying direction switching valve 106-2 is also in the first open position, as shown in Figure 4A, and that when the first conveying direction switching valve 106-1 is in the second open position, the second conveying direction switching valve 106-2 is also in the second open position, as shown in Figure 4B.

[0135] When the first conveying direction switching valve 106-1 and the second conveying direction switching valve 106-2 are in the first open position, as shown in Figure 4A, fluid is conveyed from the inlet line 110a into the fluid conveying line 108 during operation of the fluid pump 102.

[0136] The structure of the fluid delivery device 65 according to the third exemplary embodiment, which is illustrated in the lower section of Figures 4A and 4B and includes the blocking valve 107, the flow sensor 62, the pressure sensor 63, and the measuring fluid connection 90, corresponds to the structure of the fluid delivery devices 65 according to the first exemplary embodiment and the second exemplary embodiment, as shown in Figures 2 and 3 and described in this context. A repeated description of this part of the fluid delivery device 65 is therefore omitted. Instead, reference is made to the description of Figures 2 and 3.

[0137] When the first flow direction switching valve 106-1 and the second flow direction switching valve 106-2 are in their respective second open positions, as shown in Figure 4B, during operation of the fluid pump 102, fluid is conveyed from the catheter 48 through the catheter tube 47 and the fluid conveying line 108 out of the catheter 48 into the drain line 110b, so that the catheter 48 is emptied.

[0138] With a fluid delivery device 65 according to the third embodiment, as shown in Figures 4A and 4B, the catheter 48 can therefore be both filled with fluid and emptied with a single fluid pump 102.

[0139] If the first conveying direction switching valve 106-1 and the second conveying direction switching valve 106-2 are not firmly coupled and synchronized with one another, so that the synchronization between the two conveying direction switching valves 106-1, 106-2 can be canceled, an operating state of the fluid conveying device 65 can be set in which the first conveying direction switching valve 106-1 is in the first open position, as shown in Figure 4A, and the second conveying direction switching valve 106-2 is in the second open position, as shown in Figure 4B.

[0140] Such an operating state can be set to bring the delivery rate of the fluid pump 102 to its maximum achievable value during operation before the second delivery direction switching valve 106-2 is switched to the first open position to deliver fluid into the catheter 48. In this way, the fluid can be delivered into the catheter 48 at a defined delivery rate right from the start.

[0141] An operating state can also be set in which the first conveying direction reversing valve 106-1 is in the second open position (see Fig. 4B) and the second conveying direction reversing valve 106-2 is in the first open position (see Fig. 4A). In such an operating state, fluid is circulated by the fluid pump 102. This operating state can be used to flush the fluid pump 102 and the conveying direction reversing valves 106-1, 106-2 with fluid.

[0142] In the third embodiment, a device 105 for forming a flow resistance can also be provided at the fluid outlet 102b of the fluid pump 102, which device is designed to reduce or limit the measuring fluid flow achievable at maximum pumping power of the fluid pump 102 to a predetermined value in order to avoid damage to the catheter 48 due to excessive fluid flow.

[0143] The provision of a device 105a, 105b for forming a flow resistance also enables a more precise adjustment of the flow rate, since the fluid pump 102, 104 does not have to be operated in a range with a very low delivery rate, but can be operated in a higher range in which the flow rate of the fluid pump 102, 104 can be better adjusted.

[0144] As has been described in connection with the second embodiment (see Figure 3), the device 105 for forming a flow resistance can also be arranged at other points along the fluid flow, in particular upstream of the fluid inlet 102a of the fluid pump 102 and / or downstream of the second conveying direction switching valve 106-2 in the fluid conveying line 108.

[0145] If a fluid pump 102 with a low maximum delivery capacity, in particular a micropump, e.g. a piezo pump, is used as the fluid pump 102, so that there is no risk of damaging the catheter 48 by an excessive fluid flow, a device 105 for forming a flow resistance can also be dispensed with in the third embodiment.

[0146] As described in connection with the first embodiment, a separate blocking valve 107 can be dispensed with if the switching valve 106, in this case the two conveying direction switching valves 106-1, 106-2, which together form the switching valve 106, has a blocking position in which a fluid flow through the fluid conveying line 108 is blocked by the switching valve 106.

[0147] Figure 5 shows, in a highly schematic representation and partly in the form of a block diagram, the essential elements of a ventilation device 10 which comprises a fluid conveying device 65 according to the invention.

[0148] The ventilation device 10 is shown in Figure 5 in a state with the trachea 12 of a ventilated patient intubated. In addition to the trachea 712, the patient's lung lobes 28, 30, heart 32, esophagus 34, and thoracic wall 42 are also indicated very schematically in Figure 5. The tube 14 of the ventilation device 10 is inserted a short distance into the trachea 12, usually through the patient's mouth (not shown), in order to supply the airway with breathing gas. Exhaled air is also diverted via the tube 14, which branches at its upstream end 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 port of the ventilator 10 for applying an inspiratory pressure Plnsp. In the open position of the airway inlet valve 18, the airway is subjected to the inspiratory pressure Plnsp.The second end 22 is connected via an airway outlet valve 24 to an airway outlet connection of the ventilator 10 for applying an expiratory pressure PExp. In the open position of the airway outlet valve 24, the airway is subjected to the expiratory pressure PExp.

[0149] Both the inspiratory pressure Plnsp and the expiratory pressure PExp are generated by the ventilator 10 according to predetermined temporal patterns, such that inhaled respiratory gas flows toward the patient's lungs 28, 30 during an inspiration phase, as indicated by arrow 20 in Figure 5, and exhaled respiratory gas flows back from the patient's lungs 28, 30 during an expiration phase, as indicated by arrow 26. Normally, the airway inlet valve 18 remains open during the inspiration phase, and the airway inlet is pressurized with the inspiratory pressure Plnsp - which is generally greater than the expiratory pressure PExp. During the expiration phase, the airway inlet valve 18 is closed, and the airway outlet valve 24 is open. The airway inlet is then pressurized with the expiratory pressure PExp.

[0150] Any known ventilation pattern can be used, for example pressure-controlled ventilation, volume-controlled ventilation, or ventilation that combines pressure-controlled and volume-controlled aspects. In addition to purely machine-controlled ventilation, in which the temporal progression of the inspiratory pressure Plnsp and, if applicable, also the expiratory pressure PExp are determined by the ventilation device 10, ventilation patterns are also conceivable in which the patient's spontaneous breathing efforts can either support the mechanical ventilation, or the mechanical ventilation serves to support the patient's spontaneous breathing efforts. In such ventilation patterns, the temporal progression of the inspiratory pressure Plnsp or expiratory pressure PExp, and often also the position of the airway inlet valve 18 orof the airway exit valve 24 is not only determined by the ventilation device 10, but is also influenced by the patient's spontaneous breathing efforts.

[0151] The calibration of a catheter 48 insertable into the esophagus 34 with a balloon probe 46 for recording an esophageal pressure Peso, by means of which the transpulmonary pressure Ptp can be determined, is particularly tailored to ventilation modes in which ventilation is carried out using fully automatic ventilation modes, for example, ventilation using closed control loops, such as those used in the Adaptive Support Ventilation (ASV ventilation) developed by the applicant and in the INTELLiVENT-ASV ventilation also developed by the applicant. Such ventilation modes are characterized by the fact that only minimal manual intervention is required by the operating personnel, and the ventilation device automatically adjusts or maintains important ventilation parameters such as the positive end-expiratory pressure REEP or the maximum airway pressure Paw_max within predetermined value ranges using suitable closed control loops.recreates.

[0152] The breathing gas may contain ambient air, but will usually contain a predetermined proportion of pure oxygen, referred to as FiO2, which is higher than the oxygen content of the ambient air. The breathing gas will also usually be humidified.

[0153] The flow of the respiratory gas at the airway inlet is determined using an airway inlet flow sensor 36. The airway inlet flow sensor 36 detects a pressure difference dP between an inlet volume 38 and an outlet volume 40 connected to the inlet volume 38, and provides a determination of the respiratory gas mass flow at the airway inlet. The value of the airway inlet pressure Paw can also be easily derived from the pressure signal in the outlet volume 40.

[0154] The pressure prevailing in the alveoli of the lungs 28, 30 is indicated in Figure 5 by Palv. This pressure depends on the airway inlet pressure Paw as well as the flow of respiratory gas V into and out of the lungs and the airway resistance R. In the event of pressure equalization between the airway inlet and the alveoli, the alveolar pressure Palv is equal to the airway inlet pressure. Such pressure equalization results in the respiratory gas flow V' coming to a standstill. For example, a brief occlusion maneuver of the airway, ie, the airway inlet valve 18 and the airway outlet valve 24 remain closed simultaneously, can lead to pressure equalization. The occlusion maneuver must last just long enough for the gas flow V in the airway to standstill. This is usually between 1 and 5 s. In this state, the alveolar pressure Palv can then be determined by determining the airway inlet pressure Paw.In both physiological breathing and mechanical ventilation, the flow of the respiratory gas is determined by a pressure difference between the alveolar pressure Palv and the airway inlet pressure Paw.

[0155] In the case of purely physiological breathing, a negative pressure difference, i.e. a vacuum, between the alveolar pressure Palv and the airway inlet pressure Paw is created during inspiration by expansion of the thorax (indicated at 42 in Fig. 5) and the associated reduction in the pressure Ppl in the pleural space 44 formed between the thorax 42 and the lungs 28, 30. Exhalation occurs passively through relaxation of the thorax and elastic recoil of the lung tissue. For this reason, during physiological breathing, the pressure in the pleural space Ppl is always smaller than the alveolar pressure Palv. The transpulmonary pressure Ptp, defined as the difference between the alveolar pressure Palv and the pressure in the pleural space Ppl, is therefore generally positive and becomes zero in the case of complete pressure equalization.

[0156] During mechanical ventilation, the breathing gas is pumped into the lungs at positive pressure. For this reason, during mechanical ventilation, the airway inlet pressure Paw = Plnsp is greater than the alveolar pressure Palv, which in turn is greater than the pressure in the pleural space Ppl. From these pressure relationships, the transpulmonary pressure Ppl is positive during mechanical ventilation during inspiration. During expiration, the airway inlet is subjected to an airway pressure PExp that is lower than the alveolar pressure Palv, so that breathing gas flows out of the alveoli. If the airway pressure PExp is very low, it can happen that at the end of expiration, when there is very little gas left in the lungs, the pressure in the pleural space Ppl exceeds the alveolar pressure Palv to such an extent that some of the alveoli collapse. The transpulmonary pressure Ptp is then negative.

[0157] Alveolar collapse can be prevented by applying additional positive pressure to the airway entrance during the expiratory phase. This creates a constant positive airway pressure at the airway entrance, i.e., during both the inspiration and expiration phases. This positive airway pressure is referred to as positive end-expiratory pressure, or PEEP.

[0158] The transpulmonary pressure (Ptp) is therefore a suitable parameter for adjusting the PEER. However, the transpulmonary pressure (Ptp) cannot be measured directly and cannot be determined from the pressures regularly measured during mechanical ventilation, as described above.

[0159] Figure 5 schematically shows a balloon probe 46 for measuring the pressure in the esophagus 34, referred to as esophageal pressure Peso. The balloon probe 46 is in the shape of a balloon and is attached to the catheter 48 inserted into the esophagus 34. When the catheter 48 is inserted into the esophagus 34, the balloon probe 46 rests against the inside of the wall of the esophagus 34 and provides the pressure acting on the esophagus 34 at the location of the balloon probe 46. With appropriate patient positioning, this pressure corresponds to a good approximation of the pressure Ppi in the pleural space. The described balloon probe 46 for measuring the esophageal pressure P eso and the handling of this probe is described, for example, in Benditt J., Resp. Care, 2005, 50: pp. 68-77.

[0160] The ventilation device 10 also includes a device 60 for detecting an esophageal balloon pressure, as shown in Figure 1. The device 60 can be configured to provide the function of a characterization system 60 that allows the catheter 48 to be characterized and, if necessary, classified ex vivo, ie, before it is introduced into the patient's esophagus 34.

Claims

Patent claims 1. Fluid delivery device (65) for introducing and / or removing fluid into or from an esophageal catheter (48) with balloon probe (46) for determining esophageal balloon pressure, which can be inserted into an esophagus (34), comprising: - a measuring fluid port (90) which is designed for coupling with a distal end (48b) of the esophageal catheter (48) such that, in a coupled state, fluid can be introduced into the esophageal catheter (48) and / or removed from the esophageal catheter (48) via the measuring fluid port (90); - a pumping device (100) with at least one fluid pump (102), wherein the pumping device (100) is designed for conveying fluid in at least one conveying direction; and - a switching valve (106) associated with the fluid pump (102), which is switchable between at least a first position and a second position; wherein the fluid pump (102) is designed as a micropump or as a diaphragm pump.

2. Fluid conveying device (65) according to claim 1, wherein the fluid pump (102) is a first fluid pump (102) for conveying fluid in a first flow direction (R1) and wherein the pumping device (100) has a second fluid pump (104) for conveying fluid in a second flow direction (R2), wherein the second fluid pump (104) is in particular designed as a micropump or as a diaphragm pump.

3. Fluid conveying device (65) according to claim 2, wherein the first fluid pump (102) and the second fluid pump (104) are connected in parallel to each other.

4. Fluid conveying device (65) according to claim 2 or 3, wherein the switching valve (106) is designed such that it selectively connects the measuring fluid connection (90) to the first fluid pump (102) or to the second fluid pump (104).

5. Fluid conveying device (65) according to one of claims 2 to 4, wherein the switching valve (106) is arranged between the outlet of the first fluid pump (102) and the measuring fluid connection (90) and / or between the inlet of the second fluid pump (104) and the measuring fluid connection (90).

6. Fluid conveying device (65) according to claim 5, wherein the switching valve (106) is switchable between at least a first and a second opening position; wherein in the first opening position an output (102b) of the first fluid pump (102) is fluidically connected to the measuring fluid connection (90) and an input (104a) of the second fluid pump (104) is fluidically separated from the measuring fluid connection (90); and wherein in the second opening position an input (104a) of the second fluid pump (104) is fluidically connected to the measuring fluid connection (90) and an output (102b) of the first fluid pump (102) is fluidically separated from the measuring fluid connection (90).

7. Fluid conveying device (65) according to claim 6, wherein the switching valve (106) comprises a first release valve (106a) associated with the first fluid pump (102) and a second release valve (106b) associated with the second fluid pump (104); wherein the first release valve (106a) is switchable at least between an open position in which the outlet (102b) of the first fluid pump (102) is fluidically connected to the measuring fluid port (90) and a closed position in which the outlet (102b) of the first fluid pump (102) is fluidically separated from the measuring fluid port (90); and wherein the second release valve (106b) is switchable at least between an open position in which the inlet (104a) of the second fluid pump (104) is fluidically connected to is connected to the measuring fluid connection (90), and can be switched to a closed position in which the inlet (104a) of the second fluid pump (104) is fluidically separated from the measuring fluid connection (90).

8. Fluid conveying device (65) according to claim 7, wherein the first release valve (106a) and the second release valve (106b) are arranged parallel to each other.

9. Fluid conveying device (65) according to claim 7 or 8, wherein the first release valve (106a) and the second release valve (106b) are coordinated or synchronized to switch in such a way that when the first release valve (106a) is in the open position, the second release valve (106b) is in the closed position, and when the first release valve (106a) is in the closed position, the second release valve (106b) is in the open position.

10. Fluid conveying device (65) according to claim 1, wherein the switching valve (106) is designed such that it connects the measuring fluid connection (90) either to an inlet (102a) of the first fluid pump (102) or to an outlet (102b) of the fluid pump (102).

11. Fluid conveying device (65) according to claim 10, wherein the switching valve (106) comprises a first conveying direction switching valve (106-1) and a second conveying direction switching valve (106-2) which are arranged in series with respect to the flow direction of fluid through the fluid pump (102).

12. Fluid conveying device (65) according to claim 11, wherein the first conveying direction switching valve (106-1) is located downstream of the first fluid pump (102) with respect to the flow direction of fluid through the fluid pump (102); and wherein the second flow direction switching valve (106-2) is located upstream of the fluid pump (102) with respect to the flow direction of fluid through the fluid pump (102).

13. Fluid conveying device (65) according to claim 11 or 12, wherein the first conveying direction switching valve (106-1) is switchable between at least a first and a second opening position; wherein in the first opening position the outlet (102b) of the fluid pump (102) is fluidically connected to the measuring fluid port (90); and wherein in the second opening position the outlet (102b) of the fluid pump (102) is fluidically separated from the measuring fluid port (90).

14. Fluid conveying device (65) according to one of claims 11 to 13, wherein the second conveying direction switching valve (106-2) is switchable between at least a first and a second opening position; wherein in the first opening position the inlet (102a) of the fluid pump (102) is fluidically separated from the measuring fluid connection (90); and wherein in the second opening position the inlet (102a) of the fluid pump (102) is fluidically connected to the measuring fluid connection (90).

15. Fluid conveying device (65) according to one of claims 11 to 14, wherein the first conveying direction switching valve (106-1) and the second conveying direction switching valve (106-2) are coordinated or synchronized with each other in such a way that when the first conveying direction switching valve (106-1) is in the first opening position, the second conveying direction switching valve (106-2) is also in the first opening position.

16. Fluid conveying device (65) according to one of claims 11 to 15, wherein the first conveying direction switching valve (106-1) and the second conveying direction switching valve (106-2) are coordinated or synchronized with each other in such a way that when the first conveying direction- The second direction changeover valve (106-1) is in the second opening position, and the second direction changeover valve (106-2) is also in the second opening position.

17. Fluid conveying device (65) according to one of claims 1 to 16, comprising a blocking valve (107) which has at least one blocking position in which the pumping device (100) is fluidically separated from the measuring fluid connection (90).

18. Fluid conveying device (65) according to claim 17, wherein the blocking valve (107) is designed as a valve (107) separate from the switching valve (106), which is arranged in series with the switching valve (106); wherein the switching valve (106) is arranged in particular between the switching valve (106) and the measuring fluid connection (90).

19. Fluid conveying device (65) according to one of claims 1 to 18, wherein the switching valve (106) has a blocking position in which the pumping device (100) is fluidically separated from the measuring fluid connection (90).

20. Fluid conveying device (65) according to one of claims 1 to 19, wherein the first micropump (102) is designed as a piezo pump and / or wherein the second micropump (104) is designed as a piezo pump.

21. Fluid conveying device (65) according to one of claims 1 to 20, wherein a device (105, 105a, 105b) for forming a flow resistance, in particular a narrowing of the flow cross-section, is assigned to the first fluid pump (102) and / or the second fluid pump (104), which is designed in such a way that it reduces a measurement fluid flow achievable at maximum pumping power of the first fluid pump (102) and / or the second fluid pump (104) through the flow resistance to a predetermined value.

22. Fluid conveying device (65) according to one of claims 1 to 21, further comprising a flow sensor (62) which is designed to detect a measuring fluid flow conveyed by the first fluid pump (102) and / or by the second fluid pump (104), wherein the flow sensor (62) is designed in particular to detect a mass flow or volume flow of the fluid conveyed by the first fluid pump (102) and / or by the second fluid pump (104).

23. Fluid conveying device (65) according to claim 22, wherein the flow sensor (62) is arranged between the measuring fluid port (90) and the first fluid pump (102) and / or between the measuring fluid port (90) and the second fluid pump (104).

24. Fluid conveying device (65) according to one of claims 1 to 23, further comprising a pressure sensor (63) which is designed to measure a fluid pressure of the measuring fluid conveyed by the first fluid pump (102) and / or by the second fluid pump (104) in a region between the measuring fluid connection (90) and the first fluid pump (102) and / or between the measuring fluid connection (90) and the second fluid pump (104).

25. Device (60) for detecting esophageal balloon pressure based on an esophageal catheter (48) with balloon probe (46) that can be inserted into an esophagus (34), wherein the device comprises a fluid conveying device (65) according to one of the preceding claims.

26. Ventilation device (10) with a device (60) for detecting an esophageal balloon pressure according to claim 25.

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