Pulse oximetry for monitoring during ward analgesia: epidural morphine versus parenteral narcotics

A pulse oximeter was used to monitor oxygen saturation in 20 women following cesarean delivery. The patients were randomly assigned to one of two groups. Group A received conventional parenteral narcotics for relief of postoperative pain and group B received epidural morphine. All patients were monitored overnight, and data were stored continuously. There were no statistically significant differences in the low saturation values between the two groups. However, the group A desaturation episodes occurred an average of 2.7 +/- 1.9 hours after the parenteral narcotics were administered, and the group B desaturation episodes occurred an average of 13.7 +/- 5.9 hours after the epidural morphine was administered.