Brain temperature has been measured only occasionally in humans. After head trauma a temperature gradient in brain temperature compared to body temperature of up to 3°C higher in the brain has been reported. Elevated temperature is known to facilitate neuronal injury after ischemia. At present no information concerning changes in brain temperature after acute stroke is available.

In 15 patients who had suffered severe ischemic stroke in the MCA territory, intracerebral temperature was recorded using two different thermocouples, with intraventricular, epidural, and parenchymatous measurements. Body-core temperature (Foley catheter temperature) and jugular bulb temperature (n = 5) were recorded simultaneously. Measures for reducing brain temperature were compared.

In all patients brain temperature exceeded body-core temperature by at least up to l°C (range 1.0–2.1°C). Temperature in the ventricles exceeded epidural temperature by up to 2.0°C. Brain temperature modulation was independent of single pharmacological (paracetamol, metamizol) treatments. Only systemic cooling was effective and sustained hypothermic (33–34°C) brain temperatures.

After MCA stroke, human intracerebral temperature is higher than central body-core temperature. There is also a temperature gradient within the brain, with the ventricles warmer than the surface. Mild hypothermia in the treatment of severe cerebral ischemia using cooling blankets is both easy to perform and effective in the therapy of severe hemispheric infarction.