Process for operating a respirator or anesthesia device in the APRV mode taking into the impedance and/or the impedance change

1. A process for in Airway Pressure Release Ventilation (APRV) mode with at least one pressure release phase, the process comprising the steps of:

providing a measuring system for measuring the impedance and/or the impedance change of the patient's lungs;

measuring with the measuring system the impedance and/or the impedance change of the lungs of the patient being respirated; and

setting a first point in time for terminating the pressure release phase based on the measured impedance and/or impedance change.

2. A process in accordance with claim 1 , wherein said step of setting the first point in time occurs at least one of:

when a regional impedance change in the lung exceeds a global impedance change of the lung by a predetermined extent, and

when a regional impedance of the lung exceeds a global impedance of the lung by a predetermined extent.

3. A process in accordance with claim 2 , wherein the step of setting the first point in time occurs when the impedance change in a lower area of a lung cross section exceeds a predetermined percentage of the impedance change of an entire lung cross section.

4. A process in accordance with claim 3 , wherein said predetermined percentage is one of 100%, 110%, 120% and 125%.

5. A process in accordance with claim 3 , wherein said first point in time is set to when the global impedance change exceeds a value preset by a user and/or the global impedance rises above a preset amount.

6. A process in accordance with claim 1 , wherein a predetermined value for a volume to be expired for the pressure release phase is converted into an impedance and/or an impedance change used for setting the first point in time.

7. A process in accordance with claim 1 , wherein said step of measuring includes determining the impedance and/or the impedance change of the lung from at least one impedance tomogram.

8. A process in accordance with claim 7 , wherein the impedance and/or impedance change measured in an image section of the impedance tomogram is used as a local impedance and/or impedance change and the impedance and/or impedance change measured in the impedance tomogram of an entire lung is used as a global impedance and/or impedance change.

9. A process in accordance with claim 7 , wherein the impedance and/or impedance change measured in a lower quarter of the impedance tomogram or of a lung cross section is used as a local impedance and/or impedance change.

10. A process in accordance with claim 1 , further comprising the step of:

initiating a respiration process at the first point in time, wherein at least one effect of the respiration process begins at a second point in time following the first point in time;

determining the impedance present at the second point in time and/or the impedance change and/or a ratio of the regional impedance change to the global impedance change; and

controlling the actual impedance and/or the impedance change and/or the ratio of the regional impedance change to the global impedance change to the set impedance and/or the impedance change and/or the ratio of the regional impedance change to the global impedance change or controlling the set impedance and/or the impedance change and/or the ratio of the regional impedance change to the global impedance change to the actual impedance and/or the impedance change and/or the ratio of the regional impedance change to the global impedance change.

11. A process in accordance with claim 10 , further comprising the step of:

controlling the actual impedance and/or the impedance change and/or the ratio of the regional impedance change to the global impedance change to the set impedance and/or the impedance change and/or the ratio of the regional impedance change to the global impedance change by bringing forward in time the initiation of the respiration process to a third point in time such that the effect of the respiration process begins at the first point time.

12. A process in accordance with claim 10 , further comprising the step of:

calculating a deviation between the actual impedance and/or impedance change and/or the ratio of the regional impedance change to the global impedance change and the set impedance and/or the impedance change and/or the ratio of the regional impedance change to the global impedance change.

13. A process in accordance with claim 12 , further comprising the step of:

filtering and/or limiting the deviation.

14. A process in accordance with claim 12 , further comprising the step of:

calculating a control offset as a sum of a control offset of an earlier point in time and the deviation.

15. A process in accordance with claim 14 , further comprising the step of:

filtering and/or limiting the control offset.

16. A process in accordance with claim 15 , further comprising the step of:

calculating a percentage to be applied as a sum of the set impedance and/or the impedance change and/or the ratio of the regional impedance change to the global impedance change and the control offset.

17. A process for ventilating a patient in Airway Pressure Release Ventilation (APRV) mode, the process comprising the steps of:

supplying breathing gas to lungs of the patient at a high pressure for a high pressure time;

supplying breathing gas to the lungs of the patient at a low pressure;

measuring an impedance of the lungs of the patient during said supplying at the low pressure, said measuring of the impedance includes measuring a global impedance of the lungs and a regional impedance of the lungs;

switching said supplying of breathing gases between the low pressure and the high pressure, said switching including selectively switching from said supplying at the low pressure to said supplying at the high pressure based on a relationship of the regional impedance and the global impedance.

18. A process in accordance with claim 17 , wherein:

said measuring of the impedance includes measuring a plurality of impedances at several points in time during said supplying of the breathing gases at the low pressure;

said switching of said supplying from the low pressure to the high pressure occurring when one of the measured impedances fulfills a predetermined criteria.

19. A process in accordance with claim 17 , wherein:

said switching of said supplying from said supplying at the low pressure to said supplying at the high pressure occurs when the regional impedance exceeds the global impedance.

20. A process in accordance with claim 17 , wherein:

said switching of said supplying from said supplying at the low pressure to said supplying at the high pressure occurs when the change in the regional impedance exceeds the change in the global impedance.