Some effects of maintaining pulmonary nitrogenation during anaesthesia.

The effect of maintaining pulmonary nitrogenation on venous admixture during halothane anaesthesia and on postoperative hypoxaemia was studied in patients undergoing either abdominal surgery or the removal of varicose veins. In both groups venous admixture was greater when nitrogen replaced nitrous oxide in the anaesthetic gas mixture. In the varicose vein group hypoxaemia was more severe in those who received nitrogen but in the abdominal group there was little difference. It is suggested that changes in pulmonary perfusion may have influenced these results.