Online pH,pCO2 andpO2 monitoring system using two-way cyclic pumping of lactate Ringer as a baseline solution

A system for the online, simultaneous and intermittent analysis of blood pH, pCO₂ pO₂ using two-way cyclic pumping of lactate Ringer as a baseline solution is described. The multi-gas sensor is composed of a pH-ISFET with a temperature sensor, a pH-ISFET-based pCO₂ sensor and a Clark-type pO₂ sensor, bundled in an epoxy rod, and held in place in a flow cell which is directly connectable to an indwelling cannula. The system is controlled by a microcomputer, which supervises pump operation, temperature-compensation of sensor outputs, one-point calibration using sampled blood analysis, and provides graphical display of monitored results. Results of arterial blood-gas monitoring for mongrel dogs are presented which demonstrate the reliability of the present system over extended periods.