Breathing Apparatus Monitoring System

Abstract

A ventilator (1) with a respiratory device (2) for generating a respiratory gas flow for a ventilation and with a monitoring device (3) for monitoring a characteristic parameter (200) of the respiratory gas flow. A control device (4) is provided here and is suitable and configured to carry out a detection mode for a cardiac activity and to register for this a temporal profile (201) of the parameter (200) of the respiratory gas flow and to examine the temporal profile (201) of the parameter (200) for a profile structure feature (202) and to detect heartbeats in that the profile structure feature (202) fulfils a stored condition for a profile structure feature (202) which is caused by heartbeat.

Claims

1. A ventilator with at least one respiratory device for generating a respiratory gas flow for a ventilation and with at least one monitoring device for monitoring at least one characteristic parameter of the respiratory gas flow, characterized by at least one control device which is suitable and configured to carry out at least one detection mode for a cardiac activity and to register for this a temporal profile of the parameter of the respiratory gas flow and to examine the temporal profile of the parameter for at least one profile structure feature and to detect heartbeats at least in that the profile structure feature at least partially fulfils at least one stored condition for a profile structure feature caused by heartbeat.

2. The ventilator according to the preceding claim, wherein the at least one parameter is a measurement for a flow of the respiratory gas or a measurement for a pressure of the respiratory gas.

3. The ventilator according to claim 1, wherein the at least one profile structure feature describes a temporal change of the parameter and wherein as a condition at least one measurement is provided for a similarity to a temporal change of the parameter caused by heartbeats.

4. The ventilator according to claim 1, wherein the at least one profile structure feature describes a temporal flow change or pressure change and wherein the condition is at least that the temporal flow change or pressure change has a defined similarity to a temporal flow change or pressure change caused by heartbeats.

5. The ventilator according to claim 1, wherein as a condition it is at least predetermined how frequently or regularly the at least one profile structure feature occurs in the temporal profile of the parameter.

6. The ventilator according to claim 1, wherein the at least one profile structure feature describes an occurrence of maxima or minima in the temporal profile of the parameter and wherein as a condition at least one maximum threshold is provided for a value or amount of the parameter at a maximum or minimum.

7. The ventilator according to claim 1, wherein the at least one profile structure feature describes a maximum or minimum flow or a maximum or minimum pressure, and wherein as a condition at least one upper threshold is provided for an amount of the flow or pressure.

8. The ventilator according to claim 1, wherein as a condition at least one upper threshold is provided for an amount of a flow of the respiratory gas, which lies between 0.01 litres per second and 0.3 litres per second and preferably between 0.02 litres per second and 0.15 litres per second.

9. The ventilator according to claim 1, wherein as a condition provision is at least made that a sign change takes place between a maximum and a minimum in the temporal profile of the parameter.

10. The ventilator according to claim 1, wherein as a condition provision is at least made that temporal changes of the parameter and preferably an occurrence of maxima or minima take place in the temporal profile of the parameter with a defined frequency or regularity in the temporal profile of the parameter.

11. The ventilator according to claim 1, wherein as a condition provision is at least made that temporal changes of the parameter and preferably an occurrence of maxima or minima take place in the temporal profile of the parameter with a frequency of at least 10 per minute and preferably 20 per minute or in the range of 30 to 200 per minute.

12. The ventilator according to claim 1, wherein the control device is suitable and configured to examine the temporal profile of the parameter for at least one saved pattern caused by heartbeat and to detect heartbeats at least in that the pattern occurs at least approximately.

13. The ventilator according to claim 1, wherein the control device is suitable and configured to determine a frequency of the at least one profile structure feature in the temporal profile of the parameter and to determine from the frequency a number of heartbeats or a cardiac frequency.

14. The ventilator according to claim 1, wherein the control device is suitable and configured to carry out the detection of the heartbeats, taking into consideration whether the at least one profile structure feature with a minimum quality or minimum number has occurred in the registered temporal profile of the parameter or whether the temporal profile of the parameter of the respiratory gas flow was registered during a minimum duration or whether the temporal profile of the parameter of the respiratory gas flow was registered with a defined minimum signal quality.

15. The ventilator according to claim 1, wherein by means of the monitoring device a carbon dioxide content of the blood or of the respiratory gas or a blood pressure or an oxygen concentration of the blood are able to be recorded as at least one further parameter and wherein the control device is suitable and configured to register a temporal profile of the at least one further parameter and to take it at least partially into consideration for the detection of the heartbeats.

16. The ventilator according to claim 1, wherein the control device is suitable and configured, for the monitoring of a cardiac massage, to register a temporal profile of a flow or pressure of the respiratory gas at least during the cardiac massage and to evaluate an effect of the cardiac massage as a function of the temporal profile having a defined temporal flow change or pressure change.

17. The ventilator according to claim 1, wherein the control device is suitable and configured, for a detection of the heartbeats, to emit at least one indication that a cardiac massage is to be suspended or begun again.

18. The ventilator according to claim 1, wherein the respiratory device is able to be operated by means of the control device in at least one operating mode for the use of the ventilator in combination with a cardiac massage and wherein the respiratory device in the operating mode provides at least one specific ventilation for a cardiopulmonary reanimation (in English: cardiopulmonary resuscitation, CPR), so-called CPR operating mode).

19. A ventilator with at least one respiratory device for generating a respiratory gas flow for a ventilation and with at least one monitoring device for monitoring at least one characteristic parameter of the respiratory gas flow, 1, wherein in a detection mode, by means of the monitoring device flow changes or pressure changes are able to be recorded, which are caused by a beating heart in an absence of spontaneous respiratory activity and wherein a control device is suitable and configured to detect as heartbeats the flow changes or pressure changes in a registered temporal profile of the flow or pressure.

20. A monitoring system with at least one monitoring device for monitoring at least one characteristic parameter of a respiratory gas flow and with at least one control device, characterized in that the control device is suitable and configured to carry out at least one detection mode for the detecting of a cardiac activity and to register for this a temporal profile of the parameter of the respiratory gas flow and to examine the temporal profile of the parameter for at least one profile structure feature and to detect heartbeats at least in that the profile structure feature fulfils at least one stored condition for a profile structure feature which is caused by heartbeat.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Further advantages and features of the present invention will emerge from the description of the example embodiments, which are explained below with reference to the enclosed figures.

[0055] In the figures there are shown:

[0056] FIG. 1 a purely schematic illustration of a monitoring system according to the invention, in a perspective view;

[0057] FIG. 2 a highly schematized graph of a temporal profile of a parameter to illustrate the detection of heartbeats by means of the invention; and

[0058] FIG. 3 a highly schematized graph of a temporal profile of a further parameter to illustrate the detection of heartbeats by means of the invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENT(S)

[0059] FIG. 1 shows a ventilator 1 according to the invention, which is equipped with a monitoring system 10 with a monitoring device 3. The monitoring system 10 can alternatively also be used as a separate device outside the ventilator 1.

[0060] The ventilator 1 has in the interior of its housing here a respiratory device 2 which is equipped with a fan device 12 for generating a respiratory gas flow. The respiratory gas flow is delivered to the patient via a tube device 32, coupled to the respiratory device 2, with a breathing mask 22. Alternatively to the breathing mask 22, other patient interfaces can also be used. Additionally or alternatively to the fan device 12, a compressed gas source can also be provided.

[0061] The monitoring device 3 serves for the monitoring of characteristic parameters of the respiratory gas flow. The respiratory device 2 is then actuated by means of a control device 4, taking into consideration the parameter and, if applicable, further ventilation parameters.

[0062] The ventilator 1 comprises here an output device 6 with an indicator or respectively a display and an operating device 7. Combinations of operating device 7 and output device 6 can also be provided here, for example in the manner of a touch-sensitive display surface or respectively a touchscreen. The output device 6 serves here also for the issuing of indications or respectively signals within a detection mode, described later, or respectively CPR operating mode. However, the output device 6 can issue its information or respectively indications on further display devices which are not shown here, e.g. on a computer display or a tablet or smartphone or suchlike.

[0063] The respiratory device 2 is operatively connected here to a sensor means 5 which has several sensors for the recording of the characteristic parameters of the respiratory gas flow and, if applicable, further characteristic values for the ventilation. For example, the sensor means 5 comprises a pressure sensor, not shown here in closer detail, which records the pressure conditions of the respiratory gas flow, and a flow sensor, likewise not shown in closer detail, which records the flow conditions of the respiratory gas flow.

[0064] The sensor means 5 is operatively connected to the monitoring device 3 and to the control device 4, so that the recorded values can be at least partially processed by these. The sensor means 5 can be arranged in the ventilator 1 or in the tube or in the patient interface.

[0065] The fan device 12 is actuated by the control device 4, which is arranged in a non-visible manner here within the housing, so that e.g. a CPAP or an APAP- or bi-level ventilation can be carried out. For a ventilation, the respiratory device 2 is set e.g. to a defined respiratory gas flow and/or a respiratory gas pressure. The control device 4 can provide a necessary minimum pressure and/or can compensate pressure fluctuations which are caused by the respiratory activity of the user. For example, the monitoring device 3 records the present pressure in the patient interface 22 by means of the sensor means 5 and readjusts the output of the fan device 12 accordingly, until a desired ventilation pressure is present.

[0066] In a detection mode, the ventilator 1 can be operated for a cardiac activity. An automatic heartbeat detection takes place here in the detection mode. The ventilator 1 can thus establish, e.g. within a CPR, whether and when the heart begins to beat again.

[0067] An example sequence of the detection mode is now described with reference to FIG. 2. In the detection mode, the control device 4 evaluates a temporal profile 201 of the parameter 200 of the respiratory flow, which the monitoring device 3 has previously recorded by sensor (as pressure or flow or volume) and which was registered by the control device 4. The profile 201 corresponds here to a representation of the parameter 200 over the time 203, which is indicated in seconds. The profile 201 which is shown here shows a 10-second window of a recording of the flow.

[0068] The control device 4 then examines the temporal profile 201 for one or more profile structure features 202. When the examined profile structure features 202 then fulfil at least one condition which is stored in the control device 4, and for example correspond to or are similar to stored heartbeat-specific profile structure features 202, the control device 4 evaluates this as the presence of a heartbeat.

[0069] In the example shown here, the parameter corresponds to a flow of the respiratory gas flow. A temporal profile 201 of the flow is therefore drawn upon for the detection of heartbeats. The flow is indicated here in litres per second. For the evaluation, the control device 4 examines the profile 201 for specific flow changes as profile structure feature 202, which are caused by the beating heart. Alternatively or additionally, as a parameter, a pressure of the respiratory gas flow can also be recorded and analysed in a corresponding manner.

[0070] In the example which is shown here, maxima 212 and minima 222 occurring over the time 203 are drawn upon as profile structure features 202. Thereby, the flow changes which are specifically caused by the beating heart can be detected in a particularly reliable manner. A superimposing or a comparison of the profile 201 which is shown here with an electrocardiogram (ECG) (not shown), clarifies the correlation between the pressure changes and the heartbeats particularly demonstratively. The ECG shows only the electrical activity of the heart, whereas the present invention enables it to also record the pumping activity of the heart. It can be readily seen here that a maximum amount of the flow corresponds to approximately 0.1 Vs. Such a rather smaller peak flow is characteristic for the flow changes which are caused by heartbeats. The amplitude of the flow signals caused by heartbeat lies in the range 0.51/min to 3.51/min for example at 0.6 to 2.31/min. The amplitude of the pressure signals caused by heartbeat lies in the range 0.2 cm/H.sub.2O to 3.0 cm/H.sub.2O for example at 0.4 to 2.2 cm/H.sub.2O.

[0071] Additionally or alternatively, the control device 4 can also carry out a pattern detection for the profile 201, in order to detect heartbeats. For this, the profile 201 is examined for the occurrence of a particular pattern 232. In the profile 201 which is represented here for example a pattern 232 can be detected particularly well, which is characterized by the regularly occurring geometric structures with associated maxima 212 and minima 222 and the characteristic increases lying therebetween. The specific small, rhythmic oscillations in the respiratory gas flow can thus be seen here particularly well in the pattern.

[0072] The previously described detection mode can also be carried out by the monitoring system 10 according to the invention without the ventilator 1. The monitoring system 10 comprises here the monitoring device 3 and the control device 4. In order to record the parameter 200 of the respiratory gas flow, the monitoring device 3 is coupled to the patient by a suitable respiratory interface.

[0073] The monitoring system 10 can then be used for example as an autonomous system during a CPR, in order to enable an automated detection of heartbeats. The ventilation during the CPR then takes place for example manually or by means of a separate ventilator which is not shown in further detail here. The monitoring system 10 can also be coupled to an already present ventilator 1 or can be integrated therein, in order to extend its functionality by the detection mode.

[0074] The ventilator 1 offers here an operating mode for the use of the ventilator 1 in combination with a (separately carried out) cardiac massage. In such a CPR operating mode, the respiratory device 2 provides here a specific ventilation for the CPR. The ventilation can thus be undertaken by the ventilator 1 and the aider can concentrate on the CM. For example, after 30 strokes of the cardiac massage, two ventilation strokes take place by the respiratory device 2.

[0075] An example use of the ventilator 1 within a CPR proceeds for example as is described below. Firstly, the patient is connected to the ventilator 1 as intended. The ventilator 1 is moved into the CPR operating mode, so that the respiratory device 2 provides a ventilation which is particularly suitable for the CPR. Parallel to the ventilation or in an alternating manner, the cardiac massage takes place by the aider.

[0076] The ventilator 1 can assist the aider here in the CM and, for example, can signal acoustically and visually the rhythm and number of the CM. Signals can also be emitted which are indicative for the quality of the CM and indicate, for example, whether the pressure onto the thorax is sufficient. For this, pressure changes and flow changes are detected and evaluated by the control device 4 from the signals which are recorded by means of the monitoring device 3. As the pressure on the thorax brings about characteristic pressure changes and flow changes in the patient's lung, this offers a reliable monitoring.

[0077] After a particular number of, for example, 30 strokes, the ventilator 1 invites the aider to interrupt the CM. A particular number of, for example, two ventilation strokes are now applied by the respiratory device 2. After the ventilation strokes or else parallel thereto, the control device 4 activates the detection mode for the detection of the cardiac activity. For this, the temporal profile 201 of the parameter 200 is evaluated, as described above. For example, cardiogenic pressure changes and/or flow changes are sought in the temporal profile 201 and, if these fulfil particular conditions, these are identified as heartbeats.

[0078] Provision can be made here that during the recording of the parameter for the temporal profile 201 which is to be examined, a ventilation by the respiratory device 2 takes place. However, provision can also be made that the ventilation is then suspended in a targeted manner, for example so as not to influence the recording of the parameter 200. This is advantageous when the measurement conditions are difficult or respectively the signal quality of the measurement data is critical. The monitoring device 3 or respectively sensors shown here and the control unit 4 are set up and configured to record the signals caused by heartbeat also during the ventilation and/or during the CM. The signals caused by heartbeat can then be detected as oscillating fluctuations of the corresponding signals in a representation of the flow- or pressure signals.

[0079] When the control device 4 does not detect any heartbeats, an indication is emitted for the aider that the CM is to be continued. The CM is now carried out again as previously described and is accompanied by the ventilator 1 until the next detection mode takes place and so on. When the control device 4 detects heartbeats, it then emits a corresponding indication to the aider.

[0080] A further example sequence of the detection mode is now described with reference to FIG. 3. In so doing, in addition to the sequence described with reference to FIG. 2, also a plausibility check takes place here, in order to verify the result of the heartbeat detection.

[0081] For this, the control device 5 evaluates a profile 301 of a further parameter 300 registered over the time 303. The further parameter 300 here is a carbon dioxide partial pressure of the respiratory gas, which the monitoring device 3 has recorded by its own or an external sensor means.

[0082] It has been found that at the point in time 302 at which the circulatory activity begins again, a significant rise in the carbon dioxide partial pressure in the respiratory gas also occurs. Therefore, the control device 4 checks here the profile 301 of the further parameter 300 for such a rise in the carbon dioxide partial pressure. When the rise is present, e.g. an indication can be emitted. When no rise takes place, e.g. an indication can be emitted as a warning, or the detection mode can be continued or the result can be rejected.

[0083] Alternatively or additionally, a pulse oximetrically recorded plethysmogram wave and/or a pulse oximetrically measured oxygen concentration of the blood can also be drawn upon as further parameter 300. The monitoring device 3 is then e.g. operatively connected to a pulse oximeter. It can thus be established, e.g. by means of a significant change of the oxygen concentration, whether the circulatory activity has started again.

LIST OF REFERENCE NUMBERS

[0084] 1 ventilator [0085] 2 respiratory device [0086] 3 monitoring device [0087] 4 control device [0088] 5 sensor means [0089] 6 output device [0090] 7 operating device [0091] 10 monitoring system [0092] 12 fan device [0093] 22 breathing mask [0094] 32 tube device [0095] 200 parameter [0096] 201 profile [0097] 202 profile structure feature [0098] 203 time [0099] 212 maximum [0100] 222 minimum [0101] 232 pattern [0102] 300 parameter [0103] 301 profile [0104] 302 point in time [0105] 303 time