A randomised controlled trial of high-flow nasal oxygen compared with standard oxygen delivery in obese patients undergoing gastroscopy

Background: Arterial haemoglobin oxygen desaturation is common during gastroscopy and is associated with patient harm. Obesity increases the risk of desaturation during gastroscopy. High-flow nasal oxygen may reduce the risk of desaturation, but data are lacking. Methods: We conducted a single-centre, parallel group, randomised controlled trial of high-flow nasal oxygen at 50–70 l/min compared with oxygen via nasal prongs 4–10 l/min, enrolling adults having gastroscopy procedures who had a body mass index greater than 30 kg/m 2 . The primary outcome was the incidence of desaturation, defined as any peripheral oxygen saturation less than 90% during the procedure. Results: We recruited 150 participants (75 in each group). The mean body mass index was similar in each group (35 vs. 36 kg/m 2 ). High-flow nasal oxygen reduced the incidence of desaturation compared with standard oxygen therapy (three (4%) vs. 14 (19%), P = 0.005), and increased the median minimum peripheral oxygen saturation (98% (interquartile range 92–97%) vs. 94% (interquartile range 97–100%), P < 0.001). Fewer patients administered high-flow oxygen required airway interventions (39 (52%) vs. 58 (77%), P < 0.001), while the number of patients requiring interruption to the procedure for airway management were similar in each group (seven (9%) vs. five (7%), P = 0.57). High-flow nasal oxygen was associated with a higher risk of apnoea compared with standard oxygen delivery (17 (23%) vs. six (8%), P = 0.013), and a similar risk of arrhythmias existed between the groups (two (3%) vs. one (1%), P = 0.56). Conclusion: High-flow nasal oxygen reduced the incidence of desaturation during gastroscopy in obese patients.