Patent ID: 6516218
Filing Date: 2003-02-04
Classification: A61B

Abstract:
A method for detecting leads off in a multi-electrode medical diagnostic system, said multi-electrode medical diagnostic system comprising a carrier circuit unit connected to a plurality of active electrodes and a reference electrode connected to a patient to be detected; a pre-stage protecting circuit coupled to said carrier circuit unit; and a leads-off detection unit coupled to said carrier circuit unit; said method comprising the following steps:(1) generating a plurality of carrier signals of lead impedances with opposite phases and impedance pneumography by said carrier circuit unit; (2) generating a plurality of input impedance signals by said pre-stage protecting circuit to prevent the apparatus from being damaged by defibrillation; (3) demodulating said plurality of input impedance signals into lead impedance related voltages by said leads-off detection unit; (4) setting a threshold voltage of said medical diagnostic system; (5) capturing physiological signals of the patient to be detected; (6) if a current time reaches a predetermined period for checking whether a leads-off occurs, the following steps will be executed: (6.1) determining whether the plurality of the lead impedance related voltages are higher than the maximal lead impedance related voltage multiplied by a threshold value; (6.2) a corresponding bit of a status register is set to logic 1 if any of the plurality of lead impedance related voltages is higher than the maximal lead impedance related voltage multiplied by a threshold value.