The century-old practice of giving oxygen to a heart attack patient could be causing more harm than good, with a study showing patients may suffer a 20 per cent increase in damage to heart tissue if given oxygen.
A study of 411 patients treated by Ambulance Victoria MICA (Mobile Intensive Care Ambulance) paramedics found that routinely providing oxygen to someone having a heart attack was of no benefit and, in some cases, could cause further damage to the heart muscle.
The study of MRI scans showed an increase in heart damage after six months for patients given oxygen.
The results were released overnight at the American Heart Association conference in Chicago, which was one of the world’s leading medical conferences.
For more than 100 years, doctors and nurses have routinely administered oxygen to patients who are having a heart attack.
Co-researcher and Ambulance Victoria paramedic Ziad Nehme said the belief was that the oxygen would reach damaged heart tissue and lead to smaller heart attacks.
But he said the study showed that patients who received oxygen routinely suffered a 20 per cent increase in damage to the heart tissue.
“Oxygen narrows coronary arteries and reduces the blood flow to the heart and may accelerate the amount of inflammation and stress caused to heart tissue,” he said.
He said the findings were counterintuitive.
“Most people were taught, as they were going through their medical training, that oxygen would do some people a lot of good, but for everybody it would do no harm,” he said.
“This clinical trial is important. No doubt it will change practice locally, but also nationally and internationally.”
Mr Nehme said further studies would need to look into what impact oxygen treatment had on rates of death.
“We still require further studies to look more broadly at the outcomes for our patients to see whether this actually results in any increase in death over time,” he said.
Dr Tony Bartone, the Victorian president of the Australian Medical Association said the results needed to be put under more scrutiny before any decision was made about changing treatments.
“What we’ve got to understand is this is always an evolving area,” he said.
“If we look at all forms of clinical intervention, there’s always been improvements and changes on previous practices over time and as we increase our knowledge, we do make subtle tweaks.”