DEVICE FOR SUPPLYING A PATIENT WITH BREATHING GAS AND PROCESS FOR REGULATING A RESPIRATOR

• US 20080000478A1
• Filed: 05/29/2007
• Published: 01/03/2008
• Est. Priority Date: 07/01/2006
• Status: Active Grant

• Current Assignee: Dragerwerk AG & Company KGaA (FPS Vermögensverwaltung GmbH)
• Original Assignee: Draeger Medical Incorporated (FPS Vermögensverwaltung GmbH)
• Inventors: Weismann, Dieter, Eger, Marcus, Matthiessen, Hans
• Granted Patent: US 8,627,820 B2
• Time in Patent Office: Days
• US Class Current: 128/204.23
• CPC Class Codes: A61B 5/085 Measuring impedance of respiratory organs or lung elasticity
• CPC Class Codes: A61B 5/087 Measuring breath flow
• CPC Class Codes: A61M 16/0069 the speed thereof being controlled by respiratory parameters, e.g. by inhalation
• CPC Class Codes: A61M 16/026 specially adapted for predicting, e.g. for determining an information representative of a flow limitation during a ventilation cycle by using a root square technique or a regression analysis
• CPC Class Codes: A61M 16/06 Respiratory or anaesthetic masks
• CPC Class Codes: A61M 16/203 Proportional
• CPC Class Codes: A61M 2016/0027 pressure meter
• CPC Class Codes: A61M 2016/0033 electrical

Abstract

A device for supplying a patient with breathing gas, in which an initially high initial pressure p_aw(t=0) applied from the outside is automatically lowered by means of a control circuit to a lower inspiratory pressure p_aw(t) as soon as a pulmonary internal pressure p_lung(t) threatens to exceed a predetermined pulmonary target pressure p_lung,soll. Overinflation of the lungs due to the respiration is thus ruled out according to the present invention. The device permits, moreover, rapid filling of the lungs with breathing gas and makes thus possible a comparatively long phase of expiration. A process is also provided for regulating a respirator and for respirating a patient.

Claims

1. A device for supplying a patient with breathing gas for setting a desired pulmonary target pressure (p_lung,soll), the device comprising:

a breathing gas delivery means for delivering breathing gas with an inspiratory pressure (p_aw(t));

internal pressure determination means for determining a pulmonary internal pressure (p_lung(t)) during a respiration cycle;

means for setting one of a pulmonary target pressure (p_lung,soll) that is desired during the phase of inspiration and the inspiratory pressure (p_aw(t)) to an initial pressure (p_aw(t=0)) above said pulmonary target pressure (p_lung,soll);

control means for regulating said inspiratory pressure (p_aw(t)) on the basis of said pulmonary internal pressure (p_lung(t)) and said pulmonary target pressure (p_lung,soll).

2. A device in accordance with claim 1, wherein said control means lowers said inspiratory pressure (p_aw(t)) from said initial pressure (p_aw(t=0)) as a function of the difference between said pulmonary target pressure (p_lung,sol) and said pulmonary internal pressure (p_lung(t)) determined.

3. A device in accordance with claim 1, wherein said means for setting sets a maximum inspiratory pressure (p_aw,max).

4. A device in accordance with claim 1, wherein said internal pressure determination means includes measuring means for measuring a change in flow (d(dV/dt)) and a resistance (R).

5. A device in accordance with claim 4, wherein said pulmonary internal pressure (p_lung(t)) is determined from said change in flow (d(dV/dt)) as well as said resistance (R).

6. A device in accordance with claim 4, wherein said resistance is determined by means of a change in pressure and the change in flow (d(dV/dt)), which can be measured at a time of a transition from said initial pressure (p_aw(t=0)) to a lower value, said pulmonary target pressure (p_lung,sol) or to a lower pressure.

7. A device in accordance with claim 4, wherein said resistance (R) determined is discarded if said flow (dV/dt) does not equal zero when said pulmonary internal pressure (p_lung(t)) and said pulmonary target pressure (p_lung,sol) are equal, wherein the result is used to obtain an estimated value for said resistance (R).

8. A device in accordance with claim 1, wherein a flow (dV/dt) equaling zero is reached by means of one or more shutters to determine said pulmonary internal pressure (p_lung(t)).

9. A device in accordance with claim 8, wherein said resistance (R) determined is discarded if said inspiratory pressure (p_aw(t)) that becomes established after a plateau phase (t₁-t₂) has been reached does not equal said pulmonary target pressure (p_lung,soll) when said flow (dV/dt) is not equal to zero, and wherein the result is used to obtain an estimated value for said resistance (R).

10. A device in accordance with claim 1, wherein said control means has a continuous or discrete controller with P (proportional), I (integral) and/or D (derivative) components.

11. A device in accordance with claim 1, wherein said control means has a FUZZY control.

12. A device in accordance with claim 1, wherein said control means has a model-based control.

13. A device in accordance with claim 1, wherein said control means has a calculation-based leakage compensation.

14. A process for regulating a device for supplying a patient with breathing gas by setting a desired pulmonary target pressure (p_lung,soll), the process comprising the steps of:

setting a predetermined initial pressure (p_aw(t=0)) of a device-side inspiratory pressure (p_aw(t)) to a value above a pulmonary target pressure (p_lung,soll);

providing at least one-time determination of a pulmonary internal pressure (p_lung(t)) during a respiration cycle; and

lowering said inspiratory pressure (p_aw(t)) from said initial pressure (p_aw(t=0)) as a function of the difference between said pulmonary target pressure (p_lung,soll) and said pulmonary internal pressure (p_lung(t)) determined.

15. A process in accordance with claim 14, wherein said inspiratory pressure (p_aw(t)) is lowered to or below said pulmonary target pressure (p_lung,soll).

16. A process in accordance with claim 14, wherein a maximum inspiratory pressure (p_aw,max) is set on said device.

17. A process in accordance with claim 14, wherein said pulmonary internal pressure (p_lung(t)) is determined from a change in flow (d(dV/dt)) as well as a resistance R.

18. A process in accordance with claim 17, wherein said resistance (R) is determined by means of the value of a change in said inspiratory pressure (p_aw) and a change in flow (d(dV/dt)), which are measured during the transition from said initial pressure (p_aw(t=0)) to a lower value, to said pulmonary target pressure (p_lung,sol) or to a lower pressure.

19. A process in accordance with claim 17, wherein said resistance (R) determined is discarded if said flow (dV/dt) does not equal zero when said pulmonary internal pressure (p_lung(t)) and said pulmonary target pressure (p_lung,soll) are equal, and this result is used to obtain a better estimate of said resistance (R).

20. A process in accordance with claim 17, wherein a flow (dV/dt) equaling zero is reached by means of one or more shutters to determine said pulmonary internal pressure (p_lung(t)).

21. A process in accordance with claim 17, wherein said resistance (R) determined is discarded if said inspiratory pressure (p_aw(t)) that becomes established after a plateau phase (t₁-t₂) has been reached does not equal said pulmonary target pressure (p_lung,soll) at a flow (dV/dt), and this result is used to obtain a better estimate of said resistance (R).

22. A process in accordance with claim 14, wherein said inspiratory pressure (p_aw(t)) is lowered as a function of, especially in proportion to the difference between said pulmonary internal pressure (p_lung(t)) and said pulmonary target pressure (p_lung,soll), the change in this difference over time and/or the difference integrated over time.

23. A process in accordance with claim 22, wherein the difference between said pulmonary internal pressure (p_lung(t)) and said pulmonary target pressure (p_lung,soll) the change in this difference over time and/or the difference integrated over time are discretized.

24. A process in accordance with claim 23, wherein said inspiratory pressure (p_aw(t)) is lowered when the difference between said pulmonary internal pressure (p_lung(t)) and said pulmonary target pressure (p_lung,soll) drops below a predetermined threshold value.

25. A process in accordance with claim 14, wherein the lowering of said inspiratory pressure (p_aw(t)) is carried out with the use of a FUZZY control.

26. A process in accordance with claim 14, wherein the lowering of said inspiratory pressure (p_aw(t)) is carried out with the use of a model-based control.

27. A process in accordance with claim 14, wherein calculation-based leakage compensation is taken into account during the regulation of said inspiratory pressure (p_aw(t)).

28. A process for the respiration of a patient, the process comprising the steps of:

connecting a breathing gas delivery means to a patient for delivering breathing gas with an inspiratory pressure (p_aw(t));

providing an internal pressure determination means for determining a pulmonary internal pressure (p_lung(t)) during a respiration cycle;

providing a means for setting one of a pulmonary target pressure (p_lung,soll) that is desired during the phase of inspiration and the inspiratory pressure (p_aw(t)) to an initial pressure (p_aw(t=0)) above said pulmonary target pressure (p_lung,soll);

regulating said inspiratory pressure (p_aw(t)) on the basis of said pulmonary internal pressure (p_lung(t)) and said pulmonary target pressure (p_lung,soll).