Changes in Respiratory Dead Space During Halothane, Cyclopropane, and Nitrous Oxide Anesthesia

Abstract
The influence of halothane, cyclopropane and nitrous oxide anesthesia on respiratory dead space has been measured in 18 surgical patients. Dead space was found to increase progressively in each patient, with the anatomical dead space remaining relatively unchanged. The progressive increase was in alveolar dead space. Similar measurements in 5 normal awake volunteers failed to reveal appreciable changes. Arterial oxygen tensions did not fall in spite of rhythmical mechanical ventilation.