Effect of supplemental oxygen on the incidence and severity of nausea and vomiting in the patients after cesarean surgery under spinal anesthesia

Nausea and vomiting are common complications after surgery occurring in 20-70 percent of total surgeries and depends on factors such as anesthesia method and hemodynamic status, oxygen concentration, pain, etc. In some studies use of higher concentrations of oxygen prior to surgery has resulted in decreased incidence of nausea and vomiting and in some other studies such results had not been verified. In the present study, the effects of supplemental oxygen has been assessed on the incidence and severity of nausea and vomiting in the patients after cesarean surgery under spinal anesthesia This study was a randomized clinical trial and 122 women who were candidate for cesarean surgery were assigned randomly into intervention and control groups. Intervention group received 80 percent O2 equivalent to 12 liter per minute, continuously during surgery and after surgery in recovery room, and alternatively 6 hours by use of ventury mask in the ward. The control group received 30 percent O2, equivalent to 3-5 liters per minute with a regular mask as a routine measure. The incidence and severity of nausea and vomiting was recorded during surgery, up to 6 hours after surgery, in the recovery room and in the postpartum ward. According to the results, the incidence of nausea during surgery showed no significant relationship but it showed a significant difference in the recovery room and at the postpartum ward in the intervention and control groups (p<0.01). Incidence of vomiting during surgery and at the postpartum ward in the intervention and control groups had no significant difference but it revealed a significant difference in the recovery room (p<0.001). There was a significant difference in the severity of nausea in the intervention and control groups during surgery, in recovery room and after 6 hours of surgery in the postpartum ward and the severity of nausea was higher in the control group (p<0.05). This study demonstrated that supplemental oxygen therapy during and after surgery by spinal anesthesia technique was not effective for the prevention of nausea. There was only a significant statistical difference in the rate of vomiting in the recovery room between the two groups. Use of supplemental oxygen decreased the need for analgesic drugs in these patients