Pre‐oxygenation in patients living with obesity: a reply

We thank Couture and Bussières for their correspondence [1] regarding the guidelines from the Society for Obesity and Bariatric Anaesthesia on airway management in patients living with obesity [2]. One key recommendation was the focus on appropriate positioning for pre- and per-oxygenation to maximise patient oxygen stores and safe apnoeic time before airway instrumentation. We are delighted to see this important aspect of the guidelines as the subject of their correspondence. The use of spontaneous facemask positive pressure ventilation was considered; however, it is less effective than other techniques in this cohort of patients [3]. Several methods for pre-oxygenation have been described; however, variations in patient populations and individual physiology may impact their effectiveness [3]. The authors used a 25° tilting table to achieve head up positioning and a soft snorkel-type mouthpiece with a nose clip to provide positive pressure spontaneous ventilation in their studies [4, 5]. This does not reflect UK practice and is not mentioned in the guidance. Instead, we recommend that patients should be pre-oxygenated in a ramped ≥ 30° head-up position with a high inspiratory fraction of oxygen. We do not specify how this position should be achieved. Ultimately, individuals should use the equipment available to them to optimise patient positioning and oxygen delivery for pre-oxygenation and subsequent airway management.