VENTILATOR FOR VENTILATION WITH OXYGEN

Description

[0001] The invention relates to a ventilator and a method for ventilation with oxygen, which comprises a control device and a respiratory gas source for regulating the arterial oxygen saturation (SpO 2 ) by specifying an oxygen concentration (FiO2) in the respiratory gas.

[0002] Premature babies often require precisely dosed oxygen. The goal of this therapy is to provide the young patients with as much oxygen as they need, while avoiding excessively high or fluctuating oxygen levels to minimize oxygen toxicity and oxidative stress.

[0003] A negative example of oxygen oversupply is retinopathy of prematurity.

[0004] Although the optimal level of arterial oxygen saturation (SpO 2 ) is still being debated, there is evidence that large fluctuations in SpO 2 should be avoided at all costs. However, this is often difficult to achieve in the daily care of a neonatal intensive care unit. For this very reason, it makes sense to make the administration of oxygen by a ventilator dependent on the measured oxygen saturation or even to control the ventilator via SpO 2 . The invention therefore relates to precisely dosed oxygen administration in patients such as premature infants, children, or adults.

[0005] However, there are also various applications outside the field of medical technology. For example, the problem can arise in ventilators for divers or firefighters.

[0006] DE 360 4 986 A1 discloses a device for monitoring breathing and oxygen supply during sleep. The device uses sensors to determine physiological variables related to the patient's breathing or oxygen supply. Upon detection of inadequate supply, a respiratory stimulus is generated.

[0007] US Pat. No. 4,875,477 discloses a face mask with integrated sensors that can be used to determine vital signs. The sensors are arranged in the mask area and rest against the patient's face.

[0008] WO2017 / 079798A1 discloses the features of the preamble of claim 1.

[0009] The object of the present invention is to improve a ventilator of the type mentioned in the introduction in such a way that safe, automated ventilation is possible and specialist personnel can thus be largely dispensed with.

[0010] This object is achieved according to the invention by the features of the main claim.

[0011] The invention relates to a ventilator for ventilating a patient with preset values of an oxygen concentration (FiO2) in the respiratory gas, comprising a programmable control device, a respiratory gas source, an oxygen source, a gas mixing unit, a display (3) and operating elements (2) as well as at least one interface (8, 18, 28) and an oxygen sensor for determining an oxygen saturation (SpO2) of the patient, wherein the programmable control device is configured to carry out the following method: Specification of a target value or limit values for the SpO2 and specification of an FiO2 and specification of a control period (60) for ventilation with the FiO2 and ventilation with an oxygen concentration (FiO2) in the breathing gas corresponding to the specification for the duration of the control period (60) Determination of current measured values for SpO2 during the duration of the control period (60) Display of the measured values for SpO2 on the display and display of the specification for FiO2 on the display.

[0012] The measured values for SpO2 and / or the FiO2 setting can be displayed directly or indirectly (retrievably) in the form of numerical values, as an index, or as a symbol.

[0013] According to the invention, the method comprises that the ventilation takes place with an oxygen concentration (FiO2) in the respiratory gas according to the specification for the duration of the control period (60) and that measured values of the SpO2 are recorded during the ventilation and analyzed to determine whether the measured values of the SpO2 correspond to the target value and in the event of a defined deviation of the measured values of the SpO2 from the target value for the subsequent control period (60) a new specified value for FiO2 is applied.

[0014] According to the invention, the method includes calculating a change in FiO2 based on the deviation of the measured values for SpO2 from the target value, and showing a symbol (52) (for example an arrow) on the display, the symbol (52) providing the viewer with information as to whether the subsequent target value for FiO2 remains the same or is changed compared to the current FiO2 value.

[0015] The method also includes adjusting the duration of the control period (60) according to the deviation of the SpO2 measured values from the target value for the subsequent control period (60).

[0016] The procedure also includes that the control period can be specified or adjusted in the range of 20 - 240 seconds.

[0017] The method also includes dynamically displaying a time graph for the control period (60) on the display.

[0018] The procedure also includes the display of SpO2 measurements in a chronological sequence on the display.

[0019] The procedure also includes displaying FiO2 target values in a chronological manner on the display.

[0020] The procedure also includes displaying preset values for FiO2 and / or measured values for SpO2 in the form of trend curves.

[0021] The procedure also includes displaying the SpO2 and FiO2 curves one below the other.

[0022] The procedure also includes displaying the current measured value (31) for SpO2 at the end of the SpO2 curve.

[0023] The procedure also includes displaying the current FiO2 target value at the end of the FiO2 curve.

[0024] The method also includes the fact that at the end of the curve, the current preset value for FiO2 and / or the current measured value (31) for SpO2 is highlighted with an (arrow) symbol (52), whereby the orientation of the symbol (52) is dynamically adjusted based on the past measured values.

[0025] The method also includes displaying the current FiO2 preset value on the display together with a symbol (52) (e.g., an arrow), the orientation of the symbol (52) being dynamically adjusted such that the orientation of the symbol provides the viewer with information as to whether the subsequent FiO2 preset value remains the same or is changed.

[0026] The method also includes displaying the current SpO2 measurement value on the display together with a symbol (52) (e.g., an arrow), wherein the orientation of the symbol (52) is dynamically adjusted such that the orientation of the symbol provides the viewer with information as to whether the subsequent preset value for FiO2 remains the same or is changed.

[0027] The procedure also includes that if the SpO2 drops to a defined level, the current control period (60) is shortened and the FiO2 is increased for the following control period (60).

[0028] The procedure also includes visualizing a target value for SpO2 and visualizing limits, with the limits highlighted in color or visualized differently than the target values.

[0029] The procedure also includes the evaluation of measurement information from the sensor only within specified time periods.

[0030] According to the invention, the method comprises determining the signal quality (40) of the SpO2 signal, for example based on the light intensity, and visualizing it on the display in such a way that a good signal quality (40) is visually represented differently than a poor signal quality.

[0031] The procedure also includes discarding SpO2 measurement values that were determined with a defined poor signal quality (40) of the SpO2 signal.

[0032] The method also includes determining the duration of a defined poor signal quality (40) of the SpO2 signal and dynamically adjusting the control period (60) according to the duration of the defined poor signal quality.

[0033] The method also includes showing the current measured value for SpO2 (31) on the display in an SpO2 graphic (30) and also visualizing predefined limit values (32), with measured values for SpO2 that are in the target range being visually highlighted.

[0034] The object is also achieved according to the invention in that at least one parameter of the patient's blood is determined non-invasively as a respiration-dependent parameter.

[0035] To make operation of the oxygen controller as simple and intuitive as possible for the user, the control algorithm and pulse oximetry measurement have been integrated into the ventilator. All operation, including visualization of measurement data and alarm settings, is carried out via the ventilator's user interface. Particular emphasis was placed on graphically displaying the current patient status and communicating this to the user at a glance. In contrast to conventional, manual adjustment, the invention relieves the clinician of the routine adjustment of the inspiratory oxygen in the breathing gas (FiO2) by continuously monitoring the patient's needs and condition and adjusting the device settings accordingly. This is by no means intended to deprive the user of control over ventilation; rather, it can relieve them of routine tasks.Of course, it is possible to switch off the automatic control at any time in order to regulate the oxygen content manually.

[0036] Due to the continuous monitoring of the patient by the controller, which is hardly possible for the nursing staff themselves at this intensity, large saturation fluctuations could be reduced and the desired SpO2 target range could be maintained more permanently.

[0037] As one variant, this parameter is determined by a sensor positioned on the patient's skin.

[0038] Components of the blood can also be considered as blood parameters.

[0039] In particular, it is also envisaged that at least one component of the patient's blood is measured non-invasively as a respiration-dependent parameter by at least one sensor positioned on a patient's skin.

[0040] By non-invasively determining oxygen saturation during ventilation, trend values can be quickly obtained to analyze the effectiveness of the ventilator settings and disadvantages of conventional blood gas analysis can be avoided.

[0041] By non-invasively determining blood values, especially the SpO2 value, and transmitting them to the ventilator control system, the ventilator automatically adjusts the ventilation parameters so that a specified target SpO2 is achieved.

[0042] Within a predefined range of minimum and maximum limits of the ventilation settings (safety function), a ventilator is granted complete or limited autonomy to achieve the specified blood gas target values. The ventilation setting at which the target value was achieved is maintained by the device as long as the target SpO2 remains within a tolerance range.

[0043] If the target SpO2 value is exceeded, the ventilator automatically makes the necessary adjustments within the permitted ranges, for example by changing the FiO2.

[0044] By using the ventilator according to the invention, it is possible to ventilate the patient within the normal range. This value is desirable for every patient, but cannot be achieved in every patient. For this reason, the target SpO2 value can also be set and adjusted by the physician.

[0045] An embodiment of the device according to the invention thus has a ventilation autotitration with specification of the target parameter SpO2.

[0046] This is used, for example, to adjust the settings for a patient requiring long-term ventilation. This allows the physician to be partially or completely transferred to the ventilator, thus reducing costs. The device can be started with the physician's preset settings. After a certain recording period and automatic adjustment of the settings by the ventilator, the settings can be transferred to the patient and used at home.

[0047] To better respond to slowly developing changes in the disease that require device adjustment, a measuring device is placed on the patient to determine their SPO2 level, not only under physician supervision but also during home ventilation. This can be done on the ear, finger, or any other location on the body. Communication between the measuring device and the device can be achieved using various principles: wired connection, radio, infrared, Bluetooth®, mechanical, electrical, etc.

[0048] The device records the changes and, in the event of critical changes in the lungs' or patient's condition, issues a warning message, advising the attending physician to contact the attending physician. Alternatively, for certain patients, the physician can also authorize automatic changes to the ventilator's parameters. In another version of the invention, notification to the physician can also be sent directly via an interface (telephone system, mobile phone, other data transmission options, etc.).

[0049] For certain disease patterns, the preset settings present at system startup are also replaced, for example, with fixed settings stored in the ventilator. This allows the physician to select the disease pattern directly on the UI (user interface) or display, and the device takes into account important settings and their ranges characteristic of this disease, and in this case, also configures the important settings related to this disease pattern.

[0050] All monitoring functions, SPO2 parameter / alarm limit settings, and the software itself are implemented in the ventilator. The system's power supply and control, for example, are integrated / linked into the ventilator's firmware.

[0051] Precise adherence to target values can be achieved by changing the operating parameters of the ventilator within a control loop to which data from the blood parameter (SpO2) are fed as target values and actual values.

[0052] A further improved control concept can be achieved by implementing a strategy adaptation depending on the measurement result and the type of ventilation. Naming and / or assigning strategies to specific disease patterns can also be considered particularly advantageous. Thus, the device provides stored strategies with their settings and bandwidths for specific disease patterns and can respond optimally to them. These specific strategies are predefined by the device. There are also free strategies that the physician can configure, name, and save according to their preferences.

[0053] The adaptability can be further increased by selecting a mode when the operating parameter is changed.

[0054] Operator-independent operation is supported by the fact that the change in the operating parameter is carried out autonomously by the control device.

[0055] To take external control specifications into account, it is proposed that the control device evaluates operator inputs.

[0056] Precise adherence to target values is supported by the control device continuously evaluating measurement information from the sensor.

[0057] The required evaluation effort can be reduced by the control device only evaluating measurement information from the sensor within predefined time periods.

[0058] A large degree of freedom in choosing a suitable location for the sensor can be achieved by arranging the sensor in the area of a pavement.

[0059] Fast positioning of the sensor is supported by the fact that the sensor is arranged in the area of a clip.

[0060] The sensor can be attached to any well-perfused area of the body. Suitable locations include the earlobes, fingertips, temples, forehead, and the nasal area. To significantly increase usability and comfort, a transcutaneous sensor can be embedded in the forehead support of a mask for ventilation and sleep therapy.

[0061] Another preferred position is the temples, where either the forehead support or the bandages for securing the entire mask can be used for positioning. The sensor can be positioned along two axes (x, y). It is also possible to integrate the sensor into the mask's rim.

[0062] The ventilator is suitable for long-term ventilation of very small premature babies, newborns, children weighing up to 30 kilograms, and adults. The device offers basic ventilation modes such as CPAP, IPPV / IMV, SIPPV, SIMV, and PSV. Furthermore, the volume limit function can be used to restrict the delivered tidal volume. A volume-controlled tidal volume guarantee is available for assisted ventilation modes. The precise (hot-wire) flow sensor, which can be placed close to the patient, enables automatic tracking of trigger sensitivity relative to the patient's tidal volume (VT trigger adaptation). The extremely powerful, integrated high-frequency (HFO) module operates according to the membrane principle; the frequency range is between 5 and 20 Hertz. The amplitude is controlled in a regulated manner and compensates for leaks and compliance changes within the control range.The device is operated as simply and intuitively as possible via a user interface (UI) (3) or a control knob. For optimal ergonomic adaptation to the space available on the ward, the UI can be removed and attached directly to a heat therapy unit or a bed. All essential settings, measured values, alarm limits, and graphical information such as curves and loops are available at a glance. The UI can be configured by the user according to their own needs. The number of curves and loops as well as the measured values displayed can be freely selected. Manual control of inspiratory oxygen (FiO2) in patients such as premature babies who are supplied with oxygen is often complicated and time-consuming.

[0063] The inventive algorithm for automated oxygen control in patients is integrated into the ventilator. To make operation as simple and intuitive as possible for the user, the control algorithm and pulse oximetry measurement were integrated into the ventilator. All operation, including visualization of the measurement data and alarm settings, is carried out via the ventilator's display (UI). The user can determine the current graphically displayed patient status at a glance. The inventive algorithm relieves the clinician of the routine adjustment of the inspiratory oxygen in the breathing gas (FiO2) by continuously monitoring the patient's needs and condition and adjusting the device settings accordingly. This relieves the user of routine tasks. The automatic control can be switched off at any time to regulate the oxygen level manually.The algorithm of the invention can improve oxygenation in patients receiving mechanical ventilation or a nasal CPAP mask while reducing the workload associated with manual adjustment.

[0064] The pulse oximeter with sensor, for example, is connected to the serial interface of the ventilator. If the "closed loop" function is activated, the FiO2 value is automatically set, measured, and displayed during ventilation.

[0065] Fig. 1 shows the basic structure of a ventilator (1). A breathing gas source is arranged in the interior of the device in the area of a device housing with a control panel (2) and display (3). The breathing gas source can be designed as a fan and / or a breathing gas or oxygen line, or in some other way. A connecting hose (5) is connected via a coupling (4). An additional pressure measuring hose (6) can run along the connecting hose (5) and can be connected to the device housing (1) via a pressure inlet nozzle (7). The device has at least one interface (8, 18, 28). A humidifier can be adapted. The breathing gas source can be designed as a fan and / or a valve, or as an integrated high-frequency module (HFO) that operates according to the membrane principle (the typical frequency range is then between 3 and 30 Hertz).

[0066] An exhalation element (9), for example, is located in the area of the connecting tube (5) facing away from the device housing (1). An exhalation valve can also be used. Dual-tube ventilation is also possible.

[0067] Ventilator for ventilating a patient with FiO2 preset values, a control device, a respiratory gas source, an oxygen source, a display (3) and operating elements (2) as well as at least one interface (8, 18, 28) via which an SPO2 sensor is connected to the ventilator for determining an oxygen saturation of the patient, wherein the control device controls the respiratory gas source and the oxygen source to specify a defined FiO2, wherein target values for the SpO2 and / or FiO2 can be specified via the operating elements (2) or an interface, characterized in that the control unit shows current measured values and / or target values for SpO2 on the display and shows current measured values and / or preset values for FiO2 on the display.

[0068] The control device controls the respiratory gas source and the oxygen source to specify a defined FiO2, the control unit takes into account current measured values and / or target values for SpO2 and current measured values and / or target values for FiO2 for the regulation of the FiO2 at least temporarily.

[0069] The control unit displays current measured values for SpO2 on the display and current measured values and / or default values for FiO2 on the display in waveform as trend curves.

[0070] The ventilator also has a memory for at least the measured values, target values and default values.

[0071] The SpO2 and FiO2 curves are displayed one below the other.

[0072] At the end of the SpO2 curve, the current measured value (31) for SpO2 is displayed. At the end of the FiO2 curve, the current measured value for FiO2 is displayed.

[0073] At the end of the curve, the current measured value for FiO2 and / or the current measured value (31) for SpO2 is highlighted with an arrow symbol (52), whereby the orientation of the arrow (52) is dynamically adjusted based on the past measured values.

[0074] For SpO2, a target value and limits are visualized, with the limits being visualized in color or differently than the target values.

[0075] Fig. 1 Furthermore, it shows a patient interface (10) designed as a ventilation mask (10), which is implemented as a nasal mask. Fixation in the area of a patient's head can be achieved via a head cap (11). In the area of its extension facing the connecting tube (5), the patient interface (10) has a coupling element (12). The patient interface (10) can also be designed as a nasal plug, nasal cannula, or tube.

[0076] The SpO2 sensor can be connected to the ventilator via the interfaces (8, 18, 28). The interfaces can be wired, infrared, Bluetooth, or USB.

[0077] The FiO2 setpoint values are implemented in such a way that the control unit provides gas from the breathing gas source (e.g. ambient air) with the oxygen from the oxygen source in the gas mixing unit in such a way that breathing gas is provided for ventilation according to the FiO2 setpoint value.

[0078] An oxygen supply valve can be installed in the device housing. The oxygen supply valve can also be located in the ventilator and thus be part of the breathing gas source. It is conceivable to additionally enrich the breathing gas with oxygen to improve patient care.

[0079] The interface (8, 18, 28) is provided for connection to the sensor (13), which is designed to measure at least SpO2 and / or pulse rate or other blood gas values. The connection is established via a cable (14) or wirelessly. The sensor is placed on the patient (15), for example, on the finger.

[0080] One of the interfaces (8,18,28) can be provided as an interface to third-party devices and information management systems, for example for recording storage media, for connection to an ECG, EEG, printer, defibrillator, etc.

[0081] Recorded data, such as SpO2 trends, extraordinary events, warnings, or similar information such as abnormalities and operating hours, can also be transmitted via a modem or other interface (8, 18, 28) on demand or automatically. The data can be stored, analyzed, or visualized by the remote station. For example, the remote station is located in a monitoring room where users can monitor a variety of ventilators according to the invention and, if necessary, control them remotely via the interface.

[0082] To achieve the savings effect, oxygen delivery could be controlled and applied generally or during the initial inspiratory phase depending on oxygen saturation. This, along with monitoring FiO2 (FiO2 is the abbreviation for inspiratory oxygen fraction) and the resulting calculation of the difference between the actual and target values, allows for dependent oxygen delivery.

[0083] Fig. 2 shows the display (3) or the UI with fields for the representation of curves (36) of the measured values, with the setting values (35) and with an index for the signal quality (40) of the SpO2 signal.

[0084] All operation, including visualization of measurement data and alarm settings, is carried out via the (user interface of the) display of the ventilator.

[0085] The measured SpO2 value (31) is shown on the display (3), for example, as a whole number without decimal places. The signal quality (40) of the SpO2 measurement is displayed graphically. Set values (35) are visualized in a border area of the display.

[0086] The current SpO2 measurement value (31) is displayed in an SpO2 graph (30). Predefined limit values (32) are also displayed here. SpO2 measurement values within the preset range are highlighted in color, e.g., green or yellow. Values outside the preset range are preferably highlighted in red.

[0087] A field (50) visualizes the application of a temporary (adjustable) increased oxygen concentration in the breathing gas FiO2 (adjustable, for example, from 21 to 100%). In the case of a touch display (3), the user selects field (37) to briefly apply the increased oxygen concentration.

[0088] Fig. 3 Shows the signal quality (40) of the SpO2 signal as a graphic. The percentage value is displayed as a bar graph, divided into four sub-ranges: 41 (0-33%), 42 (33% - 75%), 43 (75%-90%), and 44 (90%-100%). The sub-ranges also have different colors, e.g., 41 = red, 42 = yellow, 43 = green, 44 = green.

[0089] Fig. 4 shows the display (3) or the UI with modified fields. The current SpO2 measurement value (31) is shown in an SpO2 graph (30). Predefined limit values (32) are also visualized here. However, the current SpO2 measurement value (31) is displayed as a trend value, for example, in curve form, with the current value displayed as a percentage at the end of the curve.

[0090] The current FiO2 value (51) is also displayed as a trend value, for example, in curve form, with the current value displayed as a percentage at the end of the curve. Preferably, the FiO2 curve runs below the SpO2 curve. In an example display, the measured values begin on the left and run to the right. Preferably, the curve display for SpO2 and / or FiO2 scales itself based on the measured values. Preferably, the curve display for SpO2 and / or FiO2 is displayed for the entire measurement time (70).

[0091] The current FiO2 value (51) and / or the current SpO2 measurement value (31) can be displayed with an arrow symbol (52). The arrow or symbol provides the physician or user with information about expected changes in FiO2 in the next control period.

[0092] The user therefore knows early on whether an intervention is necessary or whether the automatic process regulates the FiO2 with sufficient accuracy.

[0093] The orientation of the arrow (52) is dynamically adjusted based on the past SpO2 or FiO2 values. The arrow (52) is preferably horizontal, which means that the measured values for SpO2 are within the intended therapeutic range and a change in the FiO2 is not necessary. If the respective arrow (52) points downwards, then the trend of the past SpO2 values is upwards, towards higher measured values for SpO2. The specified FiO2 for the subsequent control period (60) would be reduced accordingly. If the respective arrow (52) points upwards, then the trend of the past SpO2 values is downwards, towards lower measured values for SpO2. The specified FiO2 for the subsequent control period (60) would be increased accordingly.

[0094] For example, if SpO2 drops, automatic control includes a shortening of the control period (60) and an increase in FiO2 for the subsequent control period (60). However, the user can also deactivate or individually configure these automatic functions.

[0095] A scale (39) for the FiO2 is arranged on the right edge of the curve display and a scale (38) for the SpO2 is arranged on the left edge of the curve display.

[0096] The curve display time or the measurement time (70) is configurable, with periods ranging from 5 minutes to 12 hours being possible, for example. 15 minutes is set here.

[0097] A time graph (60) for the control period (60) runs dynamically, for example, depending on the set therapy duration. The already elapsed therapy duration is displayed in a different color than the remaining therapy duration. Fig.5 Shows the setting of the SpO2 target range by a user. The target range has a minimum and maximum limit (32). This value range is divided into three areas, for example. These three areas include the actual target range (green) (33) with the upper (34) and lower (34) yellow ranges for normoxemia.

[0098] The control period can also be adjusted. It can be set between 10 and 600 seconds (in increments of 5 and 30 seconds). The preferred range is 30 to 180 seconds. Depending on the clinical picture, some patients react to desaturation at different rates. Therefore, the possible range is wide. During operation, the control period can also be adjusted at any time without interrupting ventilation.

[0099] The procedure will be carried out in Fig.6 explained by example.

[0100] Shown is a ventilator for ventilating a patient with preset values of an oxygen concentration (FiO2) in the respiratory gas, comprising a programmable control device, a respiratory gas source, an oxygen source, a gas mixing unit, a display (3) and operating elements (2) as well as at least one interface (8, 18, 28) and an oxygen sensor for determining an oxygen saturation (SpO2) of the patient, wherein the programmable control device is configured to carry out the following method: Specification of a target value or limit values for the SpO2 and specification of an FiO2 and specification of a control period (60) for ventilation with the FiO2 and ventilation with an oxygen concentration (FiO2) in the breathing gas corresponding to the specification for the duration of the control period (60) Determination of current measured values for SpO2 during the duration of the control period (60) Display of the measured values for SpO2 on the display and display of the specification for FiO2 on the display.

[0101] The method also includes ventilation with an oxygen concentration (FiO2) in the breathing gas corresponding to the specification for the duration of the control period (60), and SpO2 measurement values are recorded during ventilation and analyzed to determine whether the SpO2 measurement values correspond to the target value, and if the SpO2 measurement values deviate from the target value, a new FiO2 specification value is applied for the subsequent control period (60).

[0102] For standard ventilation with a specification of, for example, FiO2 = 30%, the control period (60) is 60 seconds and the limit range for SpO2 is 88% - 94%, the alarm limits are set wide.

[0103] Start with SpO2 at 91%, which is to be increased toward 100% according to a user specification. A manual change of the FiO2 from 30% to 60% is performed by the user (manual intervention by the user is possible at any time). a reduction in FiO2 of 15% occurs after the control period, while the SpO2 remains at 100%. Reduction of 8% after the control period, while the SpO2 remains at 100%. Reduction of 4% after the control period, while the SpO2 remains at 100%. The control has already reduced the FiO2 value to 33% at this point in time.

[0104] A reduction of SpO 2 to 91% has occurred.

[0105] In case of desaturation within the normal control range and up to, for example, a minimum of 70% SpO2: If the SpO 2 drops by 5%, the FiO 2 is increased by 5% for the next control period. If the SpO 2 drops by >5-10%, the FiO 2 should be increased by 8%. If the SpO 2 drops by >10%, the FiO 2 should be increased by 10%. If the drop in the SpO 2 value is stopped and the normal control range (yellow / green) is reached, normal control takes effect again.

[0106] Up to this point, the FiO2 is repeatedly increased, with the initial adjustment value being, for example, 5%, 8%, or 10%. With the preselected time window for the control range of 30 - 180 seconds.

[0107] For standard ventilation: for example, FiO 2 set = 30%, control range to 60 sec. 88% - 94% SpO2, alarm limits set wide SpO2 drop from 91% -> 84%, 7% drop in saturation Therapy control time remains at 60 sec., FiO2 increase occurs after this time always with 8% until the SpO2 is back in the "normal" range SpO2 increases to 89%, the alarms go off, the "Dynamic O2 Control" is suspended

[0108] Rapid desaturation of, for example, below 70%: There is a sudden drop in SpO2 below the limit of 70% SpO2 (regardless of the alarm setting and the preselected control range definitions). The reaction takes place within 10 seconds. A red alarm is triggered - normal control is suspended. In addition to the red alarm, the FiO2 button flashes red (alarm management escalation). All increases in FiO2 take place after 30 seconds at the latest. The normal control time setting is ignored. Falling below 70% automatically leads to the highest possible increase delta -> current FiO2 + e.g. 10% This increase is only stopped when the SpO2 measured values are back in the yellow / green / yellow range, i.e. FiO2 + 10% every 10 seconds until FiO2 100% is reached.

[0109] Standard ventilation, for example FiO2 set = 30%, CLAC at 60 sec. 88% - 94%, alarm limits set wide. SpO 2 from 91% -> 68%, 23% drop in saturation triggering high priority "Alarm SpO 2 too low - emergency control active", as well as red flashing of the FiO 2 button, as the adjustment is rapid.

[0110] Therapy control time changes to 30 seconds, the FiO2 increase is always 10% after this time until the SpO2 returns to the "normal" range.

[0111] SpO2 increases to 91%, alarms go out, "Alarm SpO2 too low - emergency control active" stops, flashing stops.

[0112] If SpO2 is now simulated from 91% -> 100%, this leads to emergency regulation reduction. 1st period (10 sec), accepted SpO2 measurement results between 95% and 100% 2nd period (10 sec), accepted SpO2 measurement results between 98% and 100% 3rd period (10 sec - 160 sec) depending on the current therapy period, accepted SpO2 measurement results 99% - 100%, the 10 seconds now last until the set therapy time has been completed, so up to 180 seconds in total.

[0113] If the last period has been completed positively, the control should regulate back half of the previously manually increased difference (emergency control).

[0114] Or the previous increase is based on the emergency increase (+ 10%), then the emergency reduction algorithm also applies.

[0115] If a value is not within these ranges for the corresponding time or if the three stages are not completed, the control is carried out as usual.

[0116] For example, it is also possible to specify a disease pattern or target value directly from the outside, whereby the device is granted almost complete autonomy over the subsequent decision-making options, depending on the degree of autonomy. The data required for device autonomy, such as settings, bandwidths, minimums, and maximums, are stored in the device and read out as needed. The device is then required to make a decision regarding the ventilation method (pressure / volume-controlled ventilation).

[0117] In the next step, for example, the system asks whether the patient should receive assisted, controlled, or assisted / controlled ventilation. Depending on the patient's level of autonomy, the device can then decide, either externally or by itself, which parameters and within which ranges, maximum and minimum ventilation parameters, should be set, or whether a list of strategies should be used. Each of these strategies contains a priority list of 1 to N different settings and is processed within its range.

[0118] For example, the current PaCO2 value can be queried and compared with the target CO2 value so that a decision can be made regarding further processing of the prioritized bandwidth. If the change to a bandwidth is exhausted, any subsequent parameter in the strategy is changed until the target CO2 value is optimally set for the patient. If a strategy is fully processed and the target CO2 value is not reached, either a new strategy, the setting of a new target CO2 value, a new ventilation method / control variables (pressure / volume controlled) or a new mode (assisted and / or controlled ventilation) could be set in order to further improve the patient's condition. This decision can either be communicated to the user and / or requested via an alarm, or it can be carried out automatically by the device.

[0119] Alternatively, the target value to be aimed for can be defined as a range, so that the device has a target to achieve. However, if strategies have been exhausted, the device can still accept the currently achieved settings as acceptable. The target value and the target value range can be configured in the device settings.

[0120] Furthermore, it is possible, for example, to grade the intensity of change and subject it to thresholding. Depending on which threshold(s) are exceeded, the intensity of change is adjusted.

Claims

1. A ventilator for ventilating a patient with setpoint values of an oxygen concentration (FiO2) in the respiratory gas, having a programmable control apparatus, a respiratory gas source, an oxygen source, a gas mixing unit, a display (3) and operating elements (2), as well as at least one interface (8, 18, 28) and an oxygen sensor for determining an oxygen saturation (SpO2) of the patient, wherein the programmable control apparatus is configured to perform the following method: • Specifying a target value or limit values for the SpO2, and • Specifying an FiO2 in the respiratory gas, and • Specifying a closed-loop control period (60) for the ventilation with the FiO2, and • Ventilating with an oxygen concentration (FiO2) in the respiratory gas corresponding to the specification for the time duration of the closed-loop control period (60) • Ascertaining current measured values for SpO2 during the time duration of the closed-loop control period (60) • Showing the measured values for SpO2 on the display, and • Showing the specification for FiO2 on the display, wherein the signal quality (40) of the SpO2 signal is ascertained, for example based on the light intensity, and visualized on the display (3) such that a good signal quality (40) is shown visually differently from a poor signal quality, characterized in that the method includes the ventilation taking place with an oxygen concentration (FiO2) in the respiratory gas corresponding to the specification for the duration of the closed-loop control period (60) and, in the process, measured values of the SpO2 being recorded during the ventilation and it being analyzed whether the measured values of the SpO2 correspond to the target value and, in the case of a defined deviation of the measured values of the SpO2 from the target value, a new setpoint value for FiO2 is calculated and / or applied for the following closed-loop control period (60) and wherein, based on the deviation of the measured values for SpO2 from the target value, a change is calculated for the FiO2 and a symbol (52) is shown on the display, wherein the symbol (52) gives the viewer information about whether the following setpoint value for FiO2 - compared to the current FiO2 value - stays the same or is changed.

2. The ventilator according to at least one of the preceding claims, characterized in that the method includes the duration of the closed-loop control period (60) being adapted for the following closed-loop control period (60) corresponding to the deviation of the measured values of SpO2 from the target value.

3. The ventilator according to at least one of the preceding claims, characterized in that the method includes the closed-loop control period being specifiable or adapted in the range of 20 - 240 seconds.

4. The ventilator according to at least one of the preceding claims, characterized in that the method includes a time graph for the closed-loop control period (60) being dynamically shown on the display.

5. The ventilator according to claim 1 or 2, characterized in that the method includes measured values for SpO2 and / or setpoint values for FiO2 being shown chronologically on the display in the form of a curve.

6. The ventilator according to at least one of the preceding claims, characterized in that the method includes setpoint values for FiO2 and / or measured values for SpO2 being shown in the form of trend curves.

7. The ventilator according to at least one of the preceding claims, characterized in that the method includes the trend curves for SpO2 and FiO2 being shown one below the other.

8. The ventilator according to at least one of the preceding claims, characterized in that the method includes the current measured value (31) for SpO2 being shown at the end of the trend curve for SpO2 and / or the current setpoint value for FiO2 being shown at the end of the trend curve for FiO2.

9. The ventilator according to at least one of the preceding claims, characterized in that the method includes a symbol (52) being placed behind the current setpoint value for FiO2 and / or the current measured value (31) for SpO2 at the end of the trend curve, wherein the orientation of the symbol (52) is adapted dynamically based on the past measured values (31).

10. The ventilator according to at least one of the preceding claims, characterized in that the method includes the current measured value for SpO2 being shown on the display together with a symbol (52), wherein the orientation of the symbol (52) is dynamically adapted such that the orientation of the symbol gives the viewer information about whether the following setpoint value for FiO2 stays the same or is changed.

11. The ventilator according to at least one of the preceding claims, characterized in that the method includes, in the case of a defined decrease in the SpO2, a shortening of the current closed-loop control period (60) and / or an increase in the FiO2 for the following closed-loop control period (60) taking place.

12. The ventilator according to at least one of the preceding claims, characterized in that the method includes a target value being visualized and limit values being visualized for SpO2, wherein limit values are emphasized in color or visualized differently from the target values.