The effect of halothane anaesthesia on the uptake of oxygen and on the respiratory pattern in man.

Nine patients were anaesthetized with halothane in oxygen using a closed-circle circuit with a Benedict-Roth spirometer substituted for the reservoir bag. The movements of the spirometer were recorded to enable the oxygen consumption and respiratory pattern to be measured continuously before surgery commenced. Increasing concentrations of halothane produced progressive decreases in oxygen uptake and in the tidal and minute volumes, but an increase in the respiratory rate.