Relation of PaCO2 to fresh gas flow in a circle system

Recent reports have described methods of controlling the level of CO2 during anesthesia with a N2O-relaxant sequence and controlled ventilation. This paper describes a method of predicting and controlling the PaCO2, using body weight for determination of the fresh gas flow from the anesthetic machine, removing the absorbent from the canister while leaving the canister in the circuit, and controlling ventilation at 12 ml/kg and at 12/min.