A Self-Calibrating, Continuous in Vivo PO₂ and PCO₂ Monitor

Abstract

Several in vivo blood gas monitoring systems have been developed which provide continuous monitoring of (1) PO₂ (systems which use miniature Clark-type electrodes),(2) PCO₂ (system of General Electric which uses a miniature and modified Severinghaus-type electrode), and (3) PO₂ and PCO₂ together using an in vivo gas collecting probe which feeds a mass spectrometer. While these systems are based on different principles, one feature common to all is the necessity for periodic calibration which requires collecting blood for analysis by a standard blood gas analyser. This paper describes a system for continuous monitoring of PO₂ and PCO₂ in body fluids which provides automatic calibration without removal of body fluids.