Oxygen administration during surgery and postoperative organ injury: observational cohort study

Abstract

ObjectiveTo examine whether supraphysiological oxygen administration during surgery is associated with lower or higher postoperative kidney, heart, and lung injury.DesignObservational cohort study.Setting42 medical centers across the United States participating in the Multicenter Perioperative Outcomes Group data registry.ParticipantsAdult patients undergoing surgical procedures ≥120 minutes’ duration with general anesthesia and endotracheal intubation who were admitted to hospital after surgery between January 2016 and November 2018.InterventionSupraphysiological oxygen administration, defined as the area under the curve of the fraction of inspired oxygen above air (21%) during minutes when the hemoglobin oxygen saturation was greater than 92%.Main outcomesPrimary endpoints were acute kidney injury defined using Kidney Disease Improving Global Outcomes criteria, myocardial injury defined as serum troponin >0.04 ng/mL within 72 hours of surgery, and lung injury defined using international classification of diseases hospital discharge diagnosis codes.ResultsThe cohort comprised 350 647 patients with median age 59 years (interquartile range 46-69 years), 180 546 women (51.5%), and median duration of surgery 205 minutes (interquartile range 158-279 minutes). Acute kidney injury was diagnosed in 19 207 of 297 554 patients (6.5%), myocardial injury in 8972 of 320 527 (2.8%), and lung injury in 13 789 of 312 161 (4.4%). The median fraction of inspired oxygen was 54.0% (interquartile range 47.5%-60.0%), and the area under the curve of supraphysiological inspired oxygen was 7951% min (5870-11 107% min), equivalent to an 80% fraction of inspired oxygen throughout a 135 minute procedure, for example. After accounting for baseline covariates and other potential confounding variables, increased oxygen exposure was associated with a higher risk of acute kidney injury, myocardial injury, and lung injury. Patients at the 75th centile for the area under the curve of the fraction of inspired oxygen had 26% greater odds of acute kidney injury (95% confidence interval 22% to 30%), 12% greater odds of myocardial injury (7% to 17%), and 14% greater odds of lung injury (12% to 16%) compared with patients at the 25th centile. Sensitivity analyses evaluating alternative definitions of the exposure, restricting the cohort, and conducting an instrumental variable analysis confirmed these observations.ConclusionsIncreased supraphysiological oxygen administration during surgery was associated with a higher incidence of kidney, myocardial, and lung injury. Residual confounding of these associations cannot be excluded.Trial registrationOpen Science Frameworkosf.io/cfd2m

Oxygen administration during general anaesthesia for surgery

“…study suggests it is time to reconsider the liberal use of oxygen during general anaesthesia. 17 The study also highlights the role of basic research in paving the road to clinical research, following the paradigm "from bench to bedside-and back." Research collaborations between biochemists and anaesthesiologists should be encouraged, especially to identify cause-effect relationships between supraphysiological oxygen administration and organ injury.…”

“…16 In a linked paper, McIlroy and colleagues (doi:10.1136/bmj-2022-070941) add to this evidence the results of a retrospective multicentre cohort study evaluating the association between high fractional oxygen administration during general anaesthesia and postoperative organ injury (primary endpoint), and 30 day mortality (secondary endpoint). 17 All the participants had surgical procedures that lasted longer than 120 minutes and >92% arterial saturation throughout the procedure. To quantify the participants' exposure to supraphysiological oxygen, McIlroy and colleagues used an algorithm to calculate the area under the curve plotting administered oxygen >21% against the time spent with oxygen saturation >92%.…”

“…In a linked paper, McIlroy and colleagues (doi:10.1136/bmj-2022-070941) add to this evidence the results of a retrospective multicentre cohort study evaluating the association between high fractional oxygen administration during general anaesthesia and postoperative organ injury (primary endpoint), and 30 day mortality (secondary endpoint) 17. All the participants had surgical procedures that lasted longer than 120 minutes and >92% arterial saturation throughout the procedure.…”

Poor housing and dark satanic mills

“…A US study finds that supraphysiological levels of oxygen administration during surgery may lead to postoperative organ injury (doi:10.1136/bmj-2022-070941). 14 Oxygen can be a double edged sword, say editorialists Michele Samaja and Davide Chiumello (doi:10.1136/bmj.o2823),15 and the use of supraphysiological oxygen levels is something that anaesthetists and surgeons must now reconsider.…”

Perioperative oxygen administration: finding the sweet spot

“…12 These data include 43 billion physiological observations from 20 million surgical cases, including minute-by-minute intraoperative data on inspired concentration of oxygen and non-invasively monitored oxyhaemoglobin saturation, baseline characteristics, and outcome data. We approached the outcomes group with our research question, built a data query, and came up with a statistical analysis plan 13. Then we accessed a well curated dataset of over 500 000 cases meeting our inclusion criteria that provided a sufficient cohort size to build the complex models capable of detecting small but potentially important effects of excess oxygen on clinical outcomes.…”