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What’s New in the Patient Safety World

January 2023

Oxygen During Surgery



Appropriate use of oxygen therapy is important. Several of our prior columns on use of oxygen in non-hypoxemic patients have shown the potential for untoward side effects.


A new study (McIlroy 2022) analyzed data on over 250,000 adult patients undergoing surgical procedures ≥120 minutes’ duration with general anesthesia and endotracheal intubation at 42 medical centers across the United States. These medical centers were participating in the Multicenter Perioperative Outcomes Group data registry. Excess use of oxygen was defined as oxygen concentrations greater than 21% for any period during which oxygen saturation was greater than 92%.


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, 12% greater odds of myocardial injury, and 14% greater odds of lung injury compared with patients at the 25th centile.


Secondary outcomes included 30-day mortality, hospital length of stay, and stroke. Increased supraphysiological oxygen administration was associated with stroke (p<0.001) and 30-day mortality (p=0.03), independent of all factors included as covariates. Patients at the 75th centile compared to those at the 25th centile of excess oxygen exposure had 9% greater odds of stroke and 6% greater odds of 30-day mortality.


Increased supraphysiological oxygen administration was associated with decreased hospital length of stay (p<0.001). Patients at the 75th centile had a 0.20 day shorter length of stay compared to those at the 25th centile (even after excluding those patients who died prior to discharge). The authors did not comment on potential reasons for this. It’s a bit unexpected. Usually, we see an increase in LOS when there is an increase in complications. Since kidney and myocardial damage were identified by lab values, perhaps these were not clinically significant enough to impact LOS.


The researchers conclude that a large clinical trial to detect small but clinically significant effects on organ injury and patient centered outcomes is needed to guide oxygen administration during surgery.


Just one more example that you can have “too much of a good thing”. We need to use sound judgement when we use supplemental oxygen in any setting.




Some of our prior columns on potential harmful effects of oxygen and other oxygen issues:


April 8, 2008 “Oxygen as a Medication”

January 27, 2009 “Oxygen Therapy: Everything You Wanted to Know and More!”

April 2009 “Nursing Companion to the BTS Oxygen Therapy Guidelines”

October 6, 2009 “Oxygen Safety: More Lessons from the UK”

July 2010 “Cochrane Review: Oxygen in MI”

December 6, 2011 “Why You Need to Beware of Oxygen Therapy”

February 2012 “More Evidence of Harm from Oxygen”

March 2014 “Another Strike Against Hyperoxia”

June 17, 2014 “SO2S Confirms Routine O2 of No Benefit in Stroke”

December 2014 “Oxygen Should Be AVOIDed”

August 11, 2015 “New Oxygen Guidelines: Thoracic Society of Australia and NZ”

November 2016 “Oxygen Tank Monitoring”

November 2016 “More on Safer Use of Oxygen”

October 2017 “End of the Oxygen in MI and Stroke Debate?”

February 2018 “Oxygen Cylinders Back in the News”

June 2018 “Too Much Oxygen”

July 2021 “Unique Way to Rapidly Identify Oxygen Flow”






McIlroy D R, Shotwell M S, Lopez M G, Vaughn M T, Olsen J S, Hennessy C et al. Oxygen administration during surgery and postoperative organ injury: observational cohort study BMJ 2022; 379: e070941





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