EFFECTS OF NITROUS OXIDE ON RESPIRATION DURING HALOTHANE ANAESTHESIA IN THE DOG

The pattern of ventilation was studied in eight greyhounds anaesthetizedwith halothane in 50% oxygen with nitrogen and in eight withthe same concentration of halothane in 50% oxygen with nitrousoxide. There was a significant reduction in both inspiratoryand expiratory times in the animals breathing nitrous oxideand an increase in the negative pressures developed in the obstructedairway during inspiration. Measurements during the additionof carbon dioxide to the inspired gases also suggested lessrespiratory depression in the nitrous oxide breathing group.It was concluded that nitrous oxide may counteract the respiratorydepressant effects of halothane.