ABSTRACT
Generation of hydrostatic pressure in the arterial systemblood pressure (BP)—is the result of two processes: the pumping of blood from the heart into the arteries-cardiac output (CO)—and the resistance against the blood flow through the vascular system-the total peripheral resistance (TPR). In its simplest form, the relationship between BP, CO, and TPR may be expressed as
BP CO TPR (9.1)
CO is derived directly from two components: the blood volume ejected by each stroke-the stroke volume (SV)— and the number of strokes per time unit-the heart rate (HR). Thus, the above central hemodynamic formula may be rewritten as
BP SV HR TPR (9.2)
A number of known physiological variables may influence one or more of the factors of Equation 9.2 (Table 9.1). Most of these variables are extensively discussed in other chapters in this book.
