Giving oxygen is often unnecessary and can cause harm
Routine oxygen therapy is not recommended for hospital patients because the benefit is uncertain and there are clear harms, say a panel of international experts in The BMJ today.
Their advice is based on new evidence that too much oxygen increases risk of death and is part of The BMJ’s ‘Rapid Recommendations’ initiative - to produce rapid and trustworthy guidance based on new evidence to help doctors make better decisions with their patients.
Oxygen therapy is widely used in hospitals and it is usual care to give extra oxygen to sick patients, often with relatively little attention paid to when to start and stop it. Guidelines also vary in their advice on when to give oxygen and how much to give.
Oxygen levels are measured by blood saturation (SpO2) - the amount of hemoglobin in the bloodstream that is saturated with oxygen to carry it through the body. Normal oxygen saturation is usually between 96% and 98%, but sick patients are often kept close to 100%.
However, a recent evidence review published in The Lancet found that giving extra oxygen to hospital patients with normal oxygen levels increases mortality. Its authors concluded that oxygen should be given conservatively, but they did not make specific recommendations on how to do it.
So an international panel - made up of specialist doctors, a nurse, a surgeon, and patients - met to discuss this latest evidence and formulate a recommendation.
Using the GRADE approach (a system used to assess the quality of evidence), they make a strong recommendation to stop oxygen therapy in patients with a saturation of 96% or higher.
For patients who have had a heart attack or stroke, they suggest not starting oxygen therapy when levels are between 90% and 92% saturation, and they strongly recommend not starting oxygen therapy when levels are at or above 93% saturation.
There was not enough evidence to say exactly when oxygen should be started for many other medical conditions such as infections.
For most patients, they say a target of 90-94% saturation seems reasonable and is low enough to avoid harm. In all cases, they advise using the minimum amount of oxygen necessary.
The authors point out that while their recommendations apply to most patients, they do not apply to surgical patients, babies, or patients with a few other uncommon conditions. And they say their recommendations may be altered as new evidence emerges.
Notes to Editors
Rapid Recommendations: Oxygen therapy for acutely ill medical patients: a clinical practice guideline
Journal: The BMJ
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