NCT02706431.

Transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) can prolong apnoea time in adults. Therefore, THRIVE used for pre-oxygenation in rapid sequence induction of anaesthesia could extend safe apnoea time during prolonged laryngoscopy and intubation. In this randomised controlled trial, we compared the lowest peripheral oxygen saturation (SpO ) during intubation when pre-oxygenating with either traditional facemask or THRIVE. Eighty adult patients, undergoing rapid sequence induction of anaesthesia for emergency surgery, were randomly allocated to pre-oxygenation with 100% oxygen with facemask or with THRIVE. Median (IQR [range]) lowest SpO until 1 min after intubation was 99% (97-100 [70-100]%) for the facemask group vs. 99% (99-100 [96-100]%) for the THRIVE group (p = 0.097). Five patients (12.5%) desaturated below 93% when pre-oxygenated with the facemask vs. none in the THRIVE group (p = 0.019). There were no differences in intubation time or apnoea time between the groups. Median intubation time was 51 (34-66 [22-261]) s in the facemask group vs. 48 (38-63 [10-146]) s in the THRIVE group (p = 0.99). Median apnoea time was 109 (86-142 [37-291]) s and 116 (92-146 [63-249]) s when using facemask and THRIVE, respectively (p = 0.49). No signs of regurgitation of gastric content were detected. The data on desaturation indicate potential benefits of oxygenation with THRIVE for rapid sequence induction compared with facemask pre-oxygenation.

Summary Pre‐oxygenation using high‐flow nasal oxygen can decrease the risk of desaturation during rapid sequence induction in patients undergoing emergency surgery. Previous studies were single‐centre and often in limited settings. This randomised, international, multicentre trial compared high‐flow nasal oxygen with standard facemask pre‐oxygenation for rapid sequence induction in emergency surgery at all hours of the day and night. A total of 350 adult patients from six centres in Sweden and one in Switzerland undergoing emergency surgery where rapid sequence induction was required were included and randomly allocated to pre‐oxygenation with 100% oxygen using high‐flow nasal oxygen or a standard tight‐fitting facemask. The primary outcome was the number of patients developing oxygen saturations <93% from the start of pre‐oxygenation until 1 min after tracheal intubation. Data from 349 of 350 patients who entered the study were analysed (174 in the high‐flow nasal oxygen group and 175 in the facemask group). No difference was detected in the number of patients desaturating <93%, five (2.9%) vs. six (3.4%) patients in the high‐flow nasal oxygen and facemask group, respectively (p = 0.77). The risk of desaturation was not increased during on‐call hours. No difference was seen in end‐tidal carbon dioxide levels in the first breath after tracheal intubation or in the number of patients with signs of regurgitation between groups. These results confirm that high‐flow nasal oxygen maintains adequate oxygen levels during pre‐oxygenation for rapid sequence induction.