Effect of nasal oxygen supplementation on safe apnea time during induction of general anaesthesia: A randomised controlled trial: Perioxygenation and safe apnea time

Objective: Apneic oxygenation increases safe apnea time and helps to secure the airway seamlessly, enhancing patient safety. Aim of this study was to determine safe apnea time achieved by perioxygenation including supplemental oxygen flow of five l/min through a nasal cannula compared to standard preoxygenation alone. Methods: This prospective double-blind randomized controlled trial included patients undergoing elective surgery under general anaesthesia with tracheal intubation. The sample size was 28 per group. Participants were randomly assigned to Groups 0 and 1. After induction of neuromuscular blockade, Group 1 received oxygen insufflation at five l/min through nasal cannula while Group 0 did not. Time to desaturate from 100 to 99% (T0), 99 to 95% (T1) and from 100 to 95% (T2) was noted. At SpO2 of 95%, ventilation was recommenced with 100% oxygen until SpO2 was restored to 100% and time to resaturation to 100% (T3) noted. Primary outcome was to determine whether perioxygenation including apneic oxygenation through nasal cannula prolongs safe apnea time. Secondary outcomes measured included resaturation time, lowest oxygen saturation levels during actual laryngoscopy and EtCO2 value immediately post intubation. Results: Demographics were similar in both the groups. Mean safe apnea time (T2) was 738 seconds in Group 1 and 325 seconds in Group 0 (p<0.001). T0 was longer in Group 1 (p<0.001). T3 was similar in both groups. Immediate EtCO2 values after intubation were higher in Group 1 (p<0.001). Conclusion: Perioxygenation including apneic nasal oxygen supplementation significantly prolongs safe apnea time.