Too Much Oxygen is No Good

Cancer surgery patients who receive 80 percent of oxygen at a higher risk for death

(RxWiki News) Less is sometimes more, as it turns out for oxygen during surgery. New research gives anesthesiologists one more variable to consider.

Having too much oxygen during surgery puts certain patients at a slightly increased risk of dying, a new study has found, particularly among cancer patients.

"Know what your anesthesiologist does before surgery."

The study, led by Christian Meyhoff, MD, PhD, from the Department of Anaesthesia, Centre of Head and Orthopaedics at Copenhagen University Hospital and colleagues, looked at the risks of giving 80 percent oxygen to patients having major surgery.

They looked at data from the PROXI study that analyzes how high concentrations of oxygen affects infection rates when it's inhaled during surgery.

Almost 1,400 patients who were having abdominal surgery were randomly grouped to receive either 80 percent or 30 percent oxygen during the procedure and for two hours afterward.

The surgeries covered a two-year time span from 2006 to 2008 with the final follow up in 2010.

Though the findings are still in the beginning stages, they found no difference in the risk of surgical would infections, contrary to what previous studies have found.

The short-term risk of death with 80 percent oxygen increased 4.4 percent compared to 2.9 percent in patients given 30 percent oxygen, but the increase is not significant.

A follow-up study looked at the risk over long-term. More deaths occurred in the high oxygen group one to three years after surgery.

Among the group with more oxygen, the death rate was 23.2 percent versus 18.3 percent in the second group.

The difference was significant only for patients who had cancer surgery. The risk of death increased 45 percent among these cancer patients given more oxygen.

There was no difference between the two groups in those who had other types of abdominal surgery.

"Until a clinical benefit of 80 percent perioperative oxygen is well-documented, we recommend abstaining from administering [oxygen concentrations] above what is needed to maintain sufficient arterial oxygen saturation," the authors said in a press release.

The study was funded by number of Danish councils, foundations and initiatives, none who influenced the design of the study.

The authors have no conflicts of interest to declare.

The report is in the October issue of Anesthesia & Analgesia from the International Anesthesia Research Society.

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Review Date: 
October 3, 2012