Reducing body temperature by just a few degrees minimises brain damage resulting from a cardiac arrest.When the heart suddenly stops - cardiac arrest - there's a great danger that the brain will be starved of oxygen. Even if the person survives, they run the risk of permanent brain damage. It's been suggested that perhaps cooling the body can reduce the brain's demand for oxygen and this may protect it after a cardiac arrest.
Doctors in Vienna have been testing this idea. They looked at patients who had experienced cardiac arrest due to ventricular fibrillation - an abnormal heart rhythm. One group had their body temperature reduced to 34 to 32 degrees - hypothermia - over 24 hours, while the other group received normal care.
AdvertisementAfter six months, 50 per cent of the hypothermia group had had a good neurologic outcome, with minimal disability, compared to 20 per cent of controls. Mortality at six months was 30 per cent in the hypothermia group, compared to 10 per cent in the controls. But there was no difference between the two groups in the complication rate seven days following the arrest. The study shows that hypothermia may indeed be an effective treatment for cardiac arrest.