Automated closed-loop versus standard manual oxygen administration after major abdominal or thoracic surgery: an international multicentre randomised controlled study.

Introduction: Hypoxaemia and hyperoxaemia may occur after surgery, with related complications. This multicentre randomised trial evaluated the impact of automated closed-loop oxygen administration after high-risk abdominal or thoracic surgeries in terms of optimising the oxygen saturation measured by pulse oximetry time within target range.
Methods: After extubation, patients with an intermediate to high risk of post-operative pulmonary complications were randomised to "standard" or "automated" closed-loop oxygen administration. The primary outcome was the percentage of time within the oxygenation range, during a 3-day frame. The secondary outcomes were the time with hypoxaemia and hyperoxaemia under oxygen.
Results: Among the 200 patients, time within range was higher in the automated group, both initially (≤3 h; 91.4±13.7% versus 40.2±35.1% of time, difference +51.0% (95% CI -42.8-59.2%); p<0.0001) and during the 3-day period (94.0±11.3% versus 62.1±23.3% of time, difference +31.9% (95% CI 26.3-37.4%); p<0.0001). Periods of hypoxaemia were reduced in the automated group (≤3 days; 32.6±57.8 min (1.2±1.9%) versus 370.5±594.3 min (5.0±11.2%), difference -10.2% (95% CI -13.9--6.6%); p<0.0001), as well as hyperoxaemia under oxygen (≤3 days; 5.1±10.9 min (4.8±11.2%) versus 177.9±277.2 min (27.0±23.8%), difference -22.0% (95% CI -27.6--16.4%); p<0.0001). Kaplan-Meier analysis depicted a significant difference in terms of hypoxaemia (p=0.01) and severe hypoxaemia (p=0.0003) occurrence between groups in favour of the automated group. 25 patients experienced hypoxaemia for >10% of the entire monitoring time during the 3 days within the standard group, as compared to the automated group (p<0.0001).
Conclusion: Automated closed-loop oxygen administration promotes greater time within the oxygenation target, as compared to standard manual administration, thus reducing the occurrence of hypoxaemia and hyperoxaemia.
Competing Interests: Conflict of interest: E. L'Her reports other from Oxynov, during the conduct of the study; personal fees from Smiths Medical, personal fees and other from GE Healthcare, grants and personal fees from Sedana Medical, outside the submitted work. In addition, E. L'Her has a patent Method and device for delivering oxygen licensed to Oxynov. Conflict of interest: S. Jaber reports personal fees from Drager, Fisher-Paykel, Baxter, Fresenius-Xenios and Medtronic, during the conduct of the study. Conflict of interest: D. Verzilli has nothing to disclose. Conflict of interest: C. Jacob has nothing to disclose. Conflict of interest: B. Huiban has nothing to disclose. Conflict of interest: E. Futier reports consulting fees from Drager Medical, GE Healthcare, Orion Pharma and Edwards Lifesciences, lecture fees from Fresenius Kabi and Getinge, and non-financial support from Fisher and Paykel Healthcare, during the conduct of the study. Conflict of interest: T. Kerforne has nothing to disclose. Conflict of interest: V. Pateau reports other from OxyNov, during the conduct of the study. Conflict of interest: P-A. Bouchard has nothing to disclose. Conflict of interest: M. Consigny has nothing to disclose. Conflict of interest: F. Lellouche reports other from Oxynov, during the conduct of the study.
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