# Mean arterial pressure

 Articles WikiDoc Resources for Mean arterial pressure

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

## Overview

The mean arterial pressure (MAP) is a term used in medicine to describe a notional average blood pressure in an individual. It is defined as the average arterial pressure during a single cardiac cycle.

## Calculation

MAP = (CO x SVR) + CVP, where[1]

CVP is usually small enough to be neglected in this formula.

## Estimation

At normal resting heart rates MAP can be approximated using the more easily measured systolic and diastolic pressures, SP and DP:[2]

MAP = DP + 1/3 (SP - DP)

or

MAP = 2/3 DP + 1/3 SP
MAP = [(2 x diastolic) + systolic] / 3

or equivalently

MAP = DP + 1/3 PP

where PP is the pulse pressure, SP-DP

At high heart rates MAP is more closely approximated by the arithmetic mean of systolic and diastolic pressures because of the change in shape of the arterial pressure pulse.[3]

## Clinical significance

MAP is considered to be the perfusion pressure seen by organs in the body.

It is believed that a MAP of greater than 60 mmHg is enough to sustain the organs of the average person under most conditions.

If the MAP falls significantly below this number for an appreciable time, the end organ will not get enough blood flow, and will become ischemic.