A case is described of cardiac arrest with resultant cerebral damage in a severely anaemic patient due to ballooning of the cuff of an endotracheal tube during the course of a 3-hour operation, whereby an insidious occlusion of the left bronchus occurred. The heart was restarted within 3 minutes. Cerebral complications were treated with urea intravenously and, to supply the brain with sufficient oxygen in spite of anaemia and oedema, oxygen in the high pressure chamber. Subjective and objective improvement during treatment in the chamber was very suggestive of an active contribution of this treatment towards total recovery.