Blood pressure, measured in millimeters of mercury (mmHg), is the pressure within the major arterial system. It is divided into systolic and diastolic determinations. Systolic blood pressure (APsys) is the maximum blood pressure during contraction of the ventricles. Diastolic blood pressure (Apdia) is the minimum pressure just prior to the next contraction.
The mean arterial pressure (MAP) measures the flow, resistance, and pressure in the arteries during one heartbeat. It is thought of as the average pressure per cardiac cycle and as a surrogate of tissue perfusion. Both high and low MAPs can indicate underlying problems. A mean arterial pressure (MAP) of less than 65 mmHg bears the risk of inadequate perfusion, leading to complications.