Microprocessor-controlled mixing system for rebreathing equilibration.

A simple, economic, and accurate microprocessor system for the determination of mixed venous PCO2 has been described. Through the automatic gas mixing system, it is possible to facilitate the use of the rebreathing equilibration technique for the purpose of cardiac output calculations. It was also possible to flush the rebreathing bag within a brief time, providing the investigator with an automatic three-way valve driven by a solenoid.