Patent ID: 6626176
Filing Date: 2003-09-30
Classification: A61M

Abstract:
A method for detecting pulse-beat signals (P) in respiratory gas flow in CPAP therapy, wherein a signal of a gas flow curve {dot over (V)}(t) is detected as a pulse-beat signal (P) when the following conditions are fulfilled:(a) {dot over (V)}maxâˆ’{dot over (V)}min&gE;&Dgr;{dot over (V)}P, and (b) tVminâˆ’tVmax&lE;&Dgr;tp, wherein &Dgr;tp>0{dot over (V)}max=local maximum of the respiratory gas flow {dot over (V)}min=local minimum of the respiratory gas flow tVmax=time of the maximal respiratory gas flow tVmin=time of the minimal respiratory gas flow &Dgr;{dot over (V)}P=empirically determined threshold value for a change of the respiratory gas flow because of a pulse-beat signal; and &Dgr;tp=maximal interval between successive maxima and minima of the pulse-beat signal, preferably 400 to 600 ms.