Effect of intra-operative high inspired fraction of oxygen on postoperative nausea and vomiting in children undergoing surgery

BACKGROUND Administration of high inspired fraction of oxygen (FiO 2 ) during anaesthesia has been proposed to decrease postoperative nausea and vomiting (PONV) in adults but has not been extensively studied in children. OBJECTIVES The primary objective of this study was to evaluate the effect of 80% FiO 2 on the incidence of PONV in children undergoing surgery. DESIGN Prospective, randomised, study. SETTING Single-centre, teaching hospital. PATIENTS Children of either gender in the age group of 5 to 15 years scheduled for elective surgeries were assessed for eligibility. Emergency surgeries; patients receiving supplemental oxygen pre-operatively or on mechanical ventilation; sepsis; bowel obstruction or ischaemia; poor nutritional status; anaemia (Hb <8 g%) or surgeries lasting less than 1 h or greater than 4 h were excluded from the study. INTERVENTIONS After induction of anaesthesia, children were randomised to receive either 30 or 80% oxygen in air, till the end of surgery. MAIN OUTCOME MEASURES Incidence of PONV within 24 h; surgical site infections (SSI)s; serum serotonin and TNF-α levels and the incidence of postoperative pulmonary complications (PPC)s were studied. RESULTS The overall 24 h incidence of PONV was not different between the low and high FiO 2 groups [24 vs. 23%; P = 0.84; odds ratio (OR) 0.92; 95% confidence interval (CI), 0.44 to 2.06]. The incidence of SSIs (15 vs. 12%; P = 0.61; OR 0.77; 95% CI, 0.28 to 2.10) and PPCs (12 vs. 8%; P = 0.38; OR 0.59; 95% CI, 0.18 to 1.92) were not significant between the low and high FiO 2 groups, respectively. Intragroup and intergroup comparisons of serum serotonin and TNF-α showed no significant difference either at baseline or at the end of surgery. CONCLUSION High intra-operative FiO 2 of 80% does not provide additional protection against PONV in children. TRIAL REGISTRATION The study was registered with Clinical Trials Registry of India (CTRI) with trial registration no: CTRI/2018/07/014974.