Oxygen Therapy May Pose Risk for Heart Attack Patients

There is little clinical evidence to support the routine use of oxygen in myocardial infarction (MI), and it may actually be detrimental, according to a new study.

Researchers at the Medical Research Institute of New Zealand (MRINZ, Wellington) conducted an historical review of literature on the use of oxygen therapy in MI since 1950. Among the findings was the fact that the only randomized, double-blind and controlled trial of oxygen therapy in the first 24 hours of myocardial infarction in 1976 showed that patients receiving routine oxygen therapy ended up having a greater amount of heart damage than those receiving room air. The likely reason for this observation was provided in a 2005 study in which the administration of high flow oxygen was shown to reduce coronary artery blood flow in stable patients with heart disease. The researchers concluded the review in a call to challenge the current clinical dogma of oxygen administration in MI and perform urgent research on the issue. The review was published in the March 2007 issue of the Journal of the Royal Society of Medicine.

"Use of oxygen to relieve angina has been available for 100 years. However, as far back as 1950, researchers have been cautioning about its routine use in myocardial infarction,” said lead author Professor Richard Beasley, M.D., director of the MRINZ. "Research in this area is scarce but cardiologists should be concerned as the balance of evidence suggests that its routine use in this clinical situation may cause harm.”

"For over 50 years and especially in the 1980s and 1990s, research has focused on the pharmacological agents in myocardial infarction and we have ignored the impact of routine oxygen use, despite earlier warnings,” continued Professor Beasley. "Oxygen therapy should only be given if the oxygen level is significantly reduced, which is uncommon in the situation of a heart attack.”


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Medical Research Institute of New Zealand