The aim of perioperative hemodynamic management strategies is to maintain adequate organ perfusion. Since organ perfusion itself is difficult to measure, systemic blood pressure is monitored as an indicator of blood flow and organ perfusion. The relationship between systemic blood pressure and systemic perfusion can be modeled by the mechanical analogue of Ohm’s law: MAP − CVP = CO × SVR, where MAP represents mean arterial pressure, CVP represents central venous pressure, CO represents cardiac output, and SVR represents systemic vascular resistance. By solving the equation for CO, it becomes apparent that changes in MAP do not always reflect changes in CO.

CO is influenced by heart rate, preload, afterload, myocardial compliance, and contractility. These variables are intimately interdependent and regulated by the autonomic nervous system and humoral factors.