Integrated Monitoring of Closed-Circuit Anaesthesia

A closed circuit is a sophisticated version of a semiclosed anaesthesia system; the overflow valve is closed, all possible leaks (including the endotracheal cuff) are minimized, and composition and mass flow of fresh gas are adjusted to maintain desired fractions of gases as well as to keep the circuit volume within acceptable limits. Supplementation of anaesthetics and oxygen must meet individual demands, which vary with time and the stage or degree of surgery.