METHOD AND APPARATUS FOR REMOVING CARDIAC NOISE FROM OUTPUT OF IMPEDANCE BLOOD METER

摘要

An impedance plethysmographic apparatus for monitoring respiration of a patient by measuring an impedance signal generated by changes occurring in the patient's chest has filter elements (30, 36) for removing cardiac artifact from the impedance signal caused by cardiac activity in the chest. The filter elements (30, 36) produces an output signal dependent only upon respiration activity in the patient's chest by removing any signals from said output caused by cardiac activity which is substantially periodic in character. There is also disclosed a method of removing cardiac artifact during monitoring of a patient's respiration using impedance plethysmography.