Sudden Death Following Cranioplasty

Cerebral pressure autoregulation is the specific intrinsic ability of the cerebrovasculature to maintain constant cerebral blood flow over a range of blood pressures. This is generally observed between a mean arterial blood pressure of approximately 50–150 mmHg and it protects against cerebral ischaemia due to hypotension and against excessive flow (malignant hyperaemia) during hypertension, when capillary damage, oedema, diffuse haemorrhage and intracranial hypertension might otherwise result. Experimental studies have shown that the main autoregulatory response is located in the small vessels (diameter of <40 um) in the brain parenchyma and this involves myogenic, neurogenic and metabolic mechanisms. These processes continuously adjust cerebrovascular resistance for changes in cerebral perfusion pressure so that the cerebral blood flow remains relatively constant. It has been demonstrated that autoregulation can be impaired over a variable time course following traumatic brain injury and this will reduce the ability of the brain to adequately control blood flow in the presence of hypo or hypertensive episodes.