Device and method for determining leaks of a respirator

1. A method for the determination of leaks in a device for supplying a patient with breathing gas, the method comprising the steps of:

providing an analyzing unit and a measuring device for determining the respiratory tract pressure;

recording an inspiration pressure p insp during an inspiration time T insp with the measuring device;

varying the inspiration pressure p insp during consecutive breaths i;

determining leak volumes V Li from the product of p inspi and T inspi in accordance with the equation

V Li =A×p inspi B ×T inspi

while the parameters A and B are determined in the analyzing unit by a regression model with p insp as the regressor.

2. A method in accordance with claim 1 , further comprising the step of adding an additive term ε i , which takes irregular breathing of the patient into consideration, to the equation for V Li .

3. A method in accordance with claim 1 , further comprising the step of additionally taking into account the end expiratory pressure peep as another regressor and thus allowing variable expiratory pressures according to the equation

V Li =A ( p inspi B ·T inspi +peep i B ·T exspi ) +ε i .

4. A device for the determination of leaks in a device for supplying a patient with breathing gas, the device comprising:

a means for producing a respiratory pressure curve;

a means for switching between an inspiration phase and an expiration phase;

a measuring device for recording an inspiration pressure p insp ; and

a means for determining leak volumes V Li from the product of p inspi and T inspi in accordance with the equation

V Li =A×p inspi B ×T inspi

with the parameters A and B to be determined by a regression calculation, wherein said means for determining leak volumes includes determining a leak flow {dot over (V)} L (t) from the positive pressure respiration curve p(t) according to the equation

{dot over (V)} L ( T )= A·p B ( t )

with the parameters A and B to be determined by a regression calculation.

5. A method for the determination of leaks in a device for supplying a patient with breathing gas, the method comprising the steps of:

providing an analyzing unit and a measuring device for determining the respiratory tract pressure;

recording an inspiration pressure p insp during an inspiration T insp with the measuring device;

determining parameters A and B with said regression model in said analyzing unit, wherein p insp is the regressor;

varying the inspiration pressure p insp during consecutive breaths i;

determining leak volumes V Li from the product of p inspi and T inspi based on the equation

V Li =A×p inspi B ×T inspi .

6. A method in accordance with claim 5 , further comprising the step of additionally taking into account the end expiratory pressure peep as another regressor and thus allowing variable expiratory pressures according to the equation

V Li =A ( p inspi B ·T inspi +peep i B ·T inspi )+ε i .

7. A method in accordance with claim 6 , further comprising:

determining an expiratory volume for each breathe to provide a plurality of expiratory volume values;

calculating a mean value based on said plurality of expiratory volume values;

determining whether one or more measured expiratory volume values is above a predetermined deviation range with respect to said mean value to define one or more irregular breathing values, wherein said step of determining said leak volumes V Li does not include said irregular breathing values.

8. A method in accordance with claim 3 , further comprising:

determining an expiratory volume for each breathe to provide a plurality of expiratory volume values;

calculating a mean value based on said plurality of expiratory volume values;

determining whether one or more measured expiratory volume values is above a predetermined deviation range with respect to said mean value to define one or more irregular breathing values, wherein said step of determining said leak volumes V Li does not include said irregular breathing values.