Temperature and brain protection in cardiac surgery

It is well known and has been clearly demonstrated that temperature plays a significant role in cerebral physiology and physiopathology, particularly in the setting of cardiac surgery with cardiopulmonary bypass (CPB). The human central nervous system (CNS) receives about 15% of the resting cardiac output and consumes about 20% of the oxygen required by the body at rest. The brain, which accounts for 2% of the total body weight, has an oxygen consumption of about 3.5 mL^-1·100 g^-1·min^-1. This high metabolic rate mandates a high blood flow; therefore, cerebral blood flow (CBF) (Fig. 13.1) is of paramount importance and is normally under metabolic, neural, myogenic, and chemical control.¹