Influence of airway resistance and ventilatory pattern on PaCO2 during enflurane anaesthesia

Tidal volume, respiratory frequency and PaCO2 were measured in 21 healthy, premedicated adults during anaesthesia with enflurane and 60 or 66% nitrous oxide in oxygen. The increase in PaCO2 correlated with the value of FEV1/VC determined before anaesthesia. PaCO2 during anaesthesia correlated with an index of airway resistance (FEV1/height) and was influenced by the pattern of breathing. These correlations are similar to those reported for halothane.