Process for switching the inspiration or expiration phase during CPAP therapy
AssigneeMAP Medizintechnik fur Arzt und Patient GmbH
InventorsHarald Vögele, Jutta Griebel, Stefan Madaus
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Abstract
A method of changing to the inhalation or exhalation phase in the CPAP therapy is provided. By means of a first, high threshold value and a second, low threshold value, nonspecific influences on the first derivative of the gas flow curve are suppressed in the respective breathing phase and the transition to the respective next gas phase is determined with high sensitivity. The advantages of the invention are in a higher precision of the changing operation and in a greater safety for the patient.
Claims10
A method for changing to the inhalation or exhalation phase (TI and TE, respectively) with a CPAP device, during a CPAP therapy of a patient, the steps comprising:
- differentiating a respiratory gas flow (V) from and to the patient with respect to time;
- changing to a respective breathing phase (i.e. inhalation or exhalation) wherein after changing to a respective breathing phase;
- comparing a first derivative (dV/dt) of the gas flow (V) with a first, high threshold value (HSE, HSI)and then a second, low threshold (NSE, NSI) for a variation of the first threshold;
- changing to a respective other breathing phase occurs when the first derivative has reached the second threshold value (NSE, NSI);
- comparing the first derivative with the second, low threshold value (NSE) in the exhalation phase;
- sampling a time history of the respiratory gas flow (V) in a sequence of at least three sampling values (X1, X2 X3);
- changing to the inhalation phase at X3 if the following two conditions
- X1+Δ<X2 and X2+Δ<X3
- Δ=predetermined increment
- are fulfilled, unless the change has already occurred earlier on account of the comparison of the first derivative with the low threshold value (NSE).
Dependencies are inferred from the claim text.