Abstract

Blood flow is normally controlled by individual tissues, providing the appropriate rate of oxygen delivery (DO2 ). Cardiac output is the result of the addition of all tissue blood flows. Cardiac output is therefore controlled at the tissues, not heart or brain. Complications in anesthesia are from lowered DO2 due to venous relaxation lowering arterial pressure. Arterial blood pressure depends on arterial volume, in turn depending on total blood volume and venous volume control. The usual idea, arterial pressure is controlled by arteriolar tone in therefore incorrect. The bases of these assertions, are outlined in sections 1 and 2, and implications in section 3. Further interesting surgical phenomena receive attention, including carotid endarterectomy effects on hypertension, and potential improvement in treatment of myocardial ischemia.