Hyperoxia for prevention of postoperative nausea and vomiting after breast cancer surgery (PONV-breast study) - a randomised controlled trial

Background/Aim. Postoperative nausea and vomiting (PONV) is one of the most common causes of patient dissatisfaction in the postoperative period after general anaesthesia. Hyperoxia may prevent PONV after abdominal surgery, but the effectiveness of intraoperative and early postoperative hyperoxia in preventing PONV after breast cancer surgery has not been adequately studied so far. Methods. Forty female patients with breast cancer were recruited, all of whom underwent surgical treatment of breast cancer with axillary sentinel node sampling or axillary lymph node dissection. Balanced general anaesthesia with propofol induction and sevofluran maintenance was administered. Twenty patients received a volatile mixture with inspiratory fraction of inspired oxygen (FiO2) of 0.8 intraoperatively and 3 L/min oxygen via face mask for two hours after surgery. The other 20 patients received a FiO2 of 0.4 during the intervention, without further administration of oxygen in the early postoperative period. The presence and severity of PONV was assessed at 30 minutes, 4/24/32/48/56 hours after surgery and a numerical PONV Intensity Scale by Wengritzky was applied to evaluate clinically significant PONV in the first 6 hours after surgery. Data were collected in Excel spreadsheet and analysed using the independent Student's t-test. Results. The overall incidence of PONV 30 minutes after the intervention was 17.5% (15% in the group of patients receiving FiO2 of 0.8 intraoperatively and 20% in the group of patients receiving volatile mixture with FiO2 of 0.4). There was no statistically significant difference (p?0.05) between the two groups in the frequency and severity of PONV, as well as in the values of PONV Intensity Score by Wengritzky. Conclusion. We found no benefit of intraand postoperative hyperoxia in reducing the incidence of PONV. The data do not support routine administration of hyperoxia in addition to antiemetics in patients undergoing breast cancer surgery for the prevention of PONV.