PROCESS AND DEVICE FOR GENERATING AN ALARM DURING A MACHINE-ASSISTED PATIENT VENTILATION

• US 20150258290A1
• Filed: 03/11/2015
• Published: 09/17/2015
• Est. Priority Date: 03/12/2014
• Status: Active Grant

• Current Assignee: Dragerwerk AG & Company KGaA (FPS Vermögensverwaltung GmbH)
• Original Assignee: Drager Medical GmbH (FPS Vermögensverwaltung GmbH)
• Inventors: LANDWEHR, Birger
• Granted Patent: US 9,962,509 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 5/091 Measuring volume of inspired or expired gases, e.g. to determine lung capacity
• CPC Class Codes: A61B 5/746 Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms alarms per se G08B
• CPC Class Codes: A61M 16/0051 with alarm devices
• CPC Class Codes: A61M 16/021 operated by electrical means A61M16/202 – A61M16/205 take precedence
• CPC Class Codes: A61M 16/024 including calculation means, e.g. using a processor
• CPC Class Codes: A61M 2016/0033 electrical
• CPC Class Codes: A61M 2205/18 with alarm
• CPC Class Codes: G16H 40/63 for local operation
• CPC Class Codes: G16Z 99/00 Subject matter not provided for in other main groups of this subclass

Abstract

A device and process generates an alarm during a machine-assisted ventilation of a patient. A minute volume is measured and a median of the minute volume and a lower critical limit value of the minute volume and a time delay are determined and are recorded in a control device. A reference signal is determined as a function of the lower critical limit value for the minute volume and the time delay based on the median of the minute volume. From the reference signal an alarm limit value located below the lower critical limit value as well as a value for a maximum tolerated duration of apnea of the patient are derivable. An alarm signal is generated both during an undershooting of the lower critical limit value over a period of time that is longer than the established time delay and during an undershooting of the alarm limit value.

Claims

1. A process for generating an alarm during a machine-assisted ventilation of a patient, the process comprising the steps of:

measuring a minute volume;

determining a median of the minute volume as well as a lower critical limit value of the minute volume and a time delay, with which time delay an alarm is generated, after undershooting the lower critical limit value;

recording the median of the minute volume, the lower critical limit value of the minute volume and the time delay in a control device;

determining a reference signal that is a function of the lower critical limit value for the minute volume and the time delay based on the median of the minute volume, from which reference signal are derived an alarm limit value located below the lower critical limit value as well as a maximum tolerated duration of apnea of the patient; and

generating an alarm signal both during an undershooting of the lower critical limit value for a period of time that is longer than the established time delay and during an undershooting of the alarm limit value.

2. A process in accordance with claim 1, wherein the determined maximum tolerated duration of apnea is issued optically and/or acoustically.

3. A process in accordance with claim 1, wherein the reference signal is determined on the basis of a time behavior of a filter being used in the measurement of the minute volume.

4. A process in accordance with claim 1, wherein the reference signal is determined on the basis of ventilation and/or breathing parameters of the patient measured during the ventilation.

5. A process in accordance with claim 1, wherein the reference signal is determined by means of hash tables, in which values for the lower critical limit value of the minute volume as well as for the maximum tolerable duration of apnea are recorded.

6. A process in accordance with claim 1, wherein pauses in breathing of the patient are determined and information about the pauses in breathing are stored in a data storage device and/or graphically displayed on an output unit.

7. A process in accordance with claim 1, wherein values for the lower critical limit value and/or values for the alarm limit value are indicated and/or input in relation to the median of the minute volume.

8. A process in accordance with claim 1, wherein a course of the minute volume is analyzed in a range between the lower critical limit value and the alarm limit value, and taking the analysis into account, the alarm signal is generated, even though the established time delay is not yet reached, or is delayed even though the established time delay has already been reached.

9. A process in accordance with claim 1, wherein information on a past course of the minute volume and/or on values of the minute volume, found to be below the lower critical limit value but above the alarm limit value, is stored.

10. A process in accordance with claim 1, wherein the information on a past course of the minute volume and/or on values of the minute volume, which were found below the lower critical limit value but above the alarm limit value, is displayed and/or transmitted to an external device.

11. A process for generating an alarm during a machine-assisted ventilation of a patient, the process comprising the steps of:

measuring a minute volume;

determining a median of the minute volume as well as a lower critical limit value of the minute volume and a maximum tolerated duration of apnea of the patient;

recording the median of the minute volume, the lower critical limit value of the minute volume and the maximum tolerated duration of apnea of the patient in a control device;

determining a reference signal that is a function of the lower critical limit value for the minute volume and the maximum tolerated duration of apnea based on the median of the minute volume, from which are derived an alarm limit value located below the lower critical limit value as well as a time delay, with which time delay an alarm is issued after undershooting the lower critical limit value; and

generating an alarm signal both during an undershooting of the lower critical time value for a period of time that is longer than the established tolerated duration of apnea and during an undershooting of the alarm limit value.

12. A process in accordance with claim 11, wherein the determined time delay, with which an alarm is issued after undershooting the lower critical time value, is sent optically and/or acoustically.

13. A process in accordance with claim 12, wherein values for the lower critical limit value of the minute volume are recorded in a first hash table and values for the time delay, the maximum tolerated duration of apnea and for the alarm limit value are recorded in a second hash table.

14. A process in accordance with claim 11, wherein the reference signal is determined on the basis of a time behavior of a filter being used in the measurement of the minute volume.

15. A process in accordance with claim 11, wherein the reference signal is determined on the basis of ventilation and/or breathing parameters of the patient measured during the ventilation.

16. A process in accordance with claim 11, wherein the reference signal is determined by means of hash tables, in which values for the lower critical limit value of the minute volume as well as for the maximum tolerable duration of apnea are recorded.

17. A process in accordance with claim 11, wherein pauses in breathing of the patient are determined and information about the pauses in breathing are stored in a data storage device and/or graphically displayed on an output unit.

18. A process in accordance with claim 11, wherein values for the lower critical limit value and/or values for the alarm limit value are indicated and/or input in relation to the median of the minute volume.

19. A process in accordance with claim 11, wherein a course of the minute volume is analyzed in a range between the lower critical limit value and the alarm limit value, and taking the analysis into account, the alarm signal is generated, even though the established time delay is not yet reached, or is delayed even though the established time delay has already been reached.

20. A process in accordance with claim 11, wherein information on a past course of the minute volume and/or on values of the minute volume, found to be below the lower critical limit value but above the alarm limit value, is stored.

21. A process in accordance with claim 11, wherein the information on a past course of the minute volume and/or on values of the minute volume, which were found below the lower critical limit value but above the alarm limit value, is displayed and/or transmitted to an external device.

22. A control device, for generating an alarm during a machine-assisted ventilation of a patient, the process comprising the steps of:

measuring a minute volume;

determining a median of the minute volume as well as a lower critical limit value of the minute volume and one of a time delay, with which time delay an alarm is generated, after undershooting the lower critical limit value and a maximum tolerated duration of apnea of the patient;

recording the median of the minute volume, the lower critical limit value of the minute volume and the one of the time delay and the maximum tolerated duration of apnea in a control device;

determining a reference signal that is a function of the lower critical limit value for the minute volume and said one of;

the time delay, based on the median of the minute volume, from which reference signal are derived an alarm limit value located below the lower critical limit value as well as a maximum tolerated duration of apnea of the patient; and

the maximum tolerated duration of apnea based on the median of the minute volume, from which are derived an alarm limit value located below the lower critical limit value as well as the time delay, with which an alarm is issued after undershooting the lower critical limit value; and

generating an alarm signal during an undershooting of the alarm limit value and also during at least one of an undershooting of the lower critical time value for a period of time that is longer than the established tolerated duration of apnea and an undershooting of the lower critical limit value for a period of time that is longer than the established time delay.

23. A control device according to claim 22, wherein software is implemented on the control for executing the measuring of the minute volume, for determining of the median of the minute volume as well as the lower critical limit value of the minute volume and the one of the time delay, with which time delay an alarm is generated, after undershooting the lower critical limit value and the maximum tolerated duration of apnea of the patient, for the recording of the median of the minute volume, the lower critical limit value of the minute volume and the one of the time delay and the maximum tolerated duration of apnea in a control device, for determining the reference signal and for generating of the alarm signal.

24. A device for monitoring a patient under machine-assisted ventilation, the device comprising:

an input unit;

an output unit;

an analysis unit; and

at least one data link for data transfer between the analysis unit and a respirator, wherein;

the analysis unit receives values of a measured minute volume, that are fed to the analysis unit via the data link;

the analysis unit is configured to determine a median of the minute volume on the basis of the measured minute volume;

the input unit comprises a menu navigation which receives a lower critical limit value of the minute volume and a time delay, with which an alarm signal, after undershooting the lower critical limit value for a period of the time delay, is generated;

the lower critical limit value of the minute volume and the time delay value are fed via the data link to the analysis unit;

alarm information is generated in the analysis unit as soon as the minute volume undershoots the lower critical limit value;

at least one reference signal that is a time behavior of a filtered minute volume signal is recorded or determined in the analysis unit;

an alarm limit value, located below the lower critical limit value, as well as a maximum tolerated duration of apnea of the patient without alarm are determinable based on the reference signal as well as the recorded values of the lower critical limit value for the minute volume and the time delay; and

an optically and/or acoustically perceptible alarm signal is issued via the output unit both during an undershooting of the lower critical limit value for a period of time which is longer than the established time delay and during an undershooting of the alarm limit value.

25. A device in accordance with claim 24, wherein values for the lower critical limit value, the alarm limit value, the time delay and the maximum tolerated duration of apnea are recorded in hash tables in the analysis unit and/or in a data storage device connected to same.

26. A device in accordance with claim 24, wherein historical information about a past course of the minute volume and/or about values of the minute volume that were found below the lower critical limit value but above the alarm limit value can be filed away in the analysis unit and/or in a data storage device connected to same and can be displayed via the output unit.