effect of oxygenation technique in general anesthesia on postoperative nausea and vomiting

ABSTRACT

To evaluate the effect of routine positive pressure mask ventilation [PPV] for preoxygenation on the occurrence of postoperative nausea and vomiting [PONV]. Double-blind randomized clinical trial. Teaching Hospital of Birjand University of Medical Sciences, Iran. One hundred sixty elective surgical patients undergoing general, urologic, and orthopedic surgeries between 2007 and 2008. Patients were divided into two groups [A and B]. All patients underwent the same method of general anesthesia using sodium thiopental, fentanyl and suxamethonium. Both groups received 100% oxygen for three minutes before induction of anesthesia. Patients in group A received positive pressure oxygenation for 30 seconds after induction of anesthesia whereas group B patients did not. The incidence of PONV and decrease in SPO[2] [saturation <89%] was compared in the two groups. Out of 160 patients, 20 patients were excluded [abdominal and laparoscopic surgeries or operation time >1 h]. Group A had 73 and group B had 67 patients. There was no decrease in SPO[2] saturation observed in the two groups. The prevalence of PONV was significantly higher in group A [45.2 Vs 28.4% for group A and B, respectively, p<0.05]. Thirty seconds of additional oxygenation with PPV after induction of anesthesia resulted in a higher incidence of PONV. There was no de-saturation in group B patients. Therefore, in non-emergency cases when a short- acting muscles relaxant drug [e.g., suxamethonium] is used, PPV before intubation can be avoided