Arterial to End-Tidal Carbon Dioxide Tension Difference During Anaesthesia in Early Pregnancy

During cesarean section the arterial to end-tidal carbon dioxide tension difference is decreased, and arterial carbon dioxide tension is closer to end-tidal carbon dioxide tension than in nonpregnant subjects, a finding which normalizes within 8 days of delivery. To assess this issue during early pregnancy, 16 patients, scheduled for termination of pregnancy at the end of the first trimester, were induced and maintained in general anesthesia with a thiopental-succinylcholine-nitrous oxide-halothane combination, with a minute volume of 80 ml/kg/min. End-tidal CO2 and arterial blood CO2 tensions were periodically determined to determine arterial to end-tidal carbon dioxide tension differences.