Method for judging the reverse connection of a flow sensor and a respiratory mechanics measuring module used therein

A method for judging the reverse connection of a flow sensor in respiratory mechanics measurement, comprising the following steps of:

• a. providing a respiratory mechanics measuring module and connecting thereto the flow sensor to be judged, the respiratory mechanics measuring module comprising a differential pressure sensor, a sampled signal processing circuit and an alarm;
• b. measuring four pressure intensity values x1, x2, x3 and x4 of a respiratory gas in an airway corresponding to four consecutive sampling points of time within an arbitrary time interval and the flow value S of that time interval using the differential pressure sensor and the flow sensor, and calculating three pressure difference variables in the sampled signal processing circuit using the equations dx1=x1−x2, dx2=x2−x3 and dx3=x3−x4;
• c. sending an alarm signal indicating the reverse connection of the flow sensor with the alarm, if x1, x2 and x3 are all smaller than zero and meanwhile x1 and x3 are equal to or greater than x2, and the flow value S is smaller than a predetermined first threshold value f1;
• or if dx1, dx2 and dx3are all greater than zero and meanwhile dx1 and dx3 are smaller than or equal to dx2, and the flow value S is greater than a predetermined second threshold value f2.