Safety limits of controlled hypotension in humans

Controlled hypotension is a safe and convenient means of allowing a surgeon to perform intracranial aneurysm, arteriovenous malformation and vascular tumor surgery. The mean arterial pressure between 40 and 60 mmHg induces diminished pulsatile arterial pressure, thus preventing rupture of these abnormal vasculatures. It is still possible to maintain cerebral metabolism in the functional level within this 40-60 mmHg blood pressure range. This statement is based on our experience of the physical and neurological outcome of patients after surgery, and on analyses of somatosensory evoked potential and redox of cytochrome a, a3 in the mitochondria of the cerebral cortical cells.