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.

$MAP\; =\; (CO\; \backslash times\; SVR)\; +\; CVP$, where

• $CO$ is cardiac output
• $SVR$ is systemic vascular resistance
• $CVP$ is central venous pressure

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

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

$MAP\; \backslash simeq\; DP\; +\; \backslash frac\{1\}\{3\}(SP\; -\; DP)$

or equivalently

$MAP\; \backslash simeq\; DP\; +\; \backslash frac\{1\}\{3\}PP$

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.

$MAP$ 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.

See also

• Blood pressure
• Hypertension
• Pulse pressure

External links

• Cardiovascular Physiology Concepts: Mean Arterial Pressure, Richard E. Klabunde, Ph.D

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