Abstract PR576

Abstract

Background & Objectives: Several methods including positive airway pressure and head-up tilt during preoxygenation have shown to extend the apnea period. However, uniform recommendations have not yet been made. In the present study, we compared the effect of preoxygenation with 5 cmH2O CPAP in supine and 25° head up position on non-hypoxic apnea period. Materials & Methods: Forty non-obese adult patients undergoing elective surgery with general anaesthesia were enrolled in this randomized controlled trial. The patients were randomly divided into two groups (20 in each group); group S received preoxygenation in supine position with 5 cmH2O CPAP and group H received preoxygenation in 25° head-up position with 5 cmH2O CPAP. Following preoxygenation for 3 min, anesthesia was induced and trachea intubated. The tracheal tube was exposed to atmosphere till the SpO2 dropped to 92%, after which ventilation was resumed and subsequently standard anaesthesia protocol was followed. Haemodynamic parameters and arterial blood gas were measured at various time intervals; baseline, after pre-oxygenation, and when SpO2 reached 92% during apnea period. The time taken for SpO2 to reach 92% from the end of induction of anaesthesia and time to recovery of SpO2 to 100% following resumption of ventilation was recorded. Results: The median duration of non-hypoxic apnea period was significantly longer in H group [405 (305-475) s] as compared to the S group [338 (255-367) s; P=0.005]. The time to recovery of SPO2 after apnea in H group and S group was [30.50 (26.25-43.25) s] and [31 (26-40) s; P=0.85] respectively. No significant adverse events were observed. Conclusion: In non-obese healthy adults, preoxygenation with 5 cmH2O CPAP in 25° head-up position was found to prolong non-hypoxic apnea period compared with 5 cmH2O CPAP in supine position. Disclosure of Interest: None declared