Mean arterial pressure

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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.

Contents 1 Calculation 2 Estimation 3 Clinical significance 4 See also 5 References

[edit] Calculation

, where^[1]

• 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.

[edit] Estimation

At normal resting heart rates MAP can be approximated using the more easily measured systolic and diastolic pressures, SP and DP:^[2][3]

or

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

or equivalently

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.

[edit] 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.

[edit] See also

• Blood pressure
• Hypertension
• Pulse pressure

[edit] References

1. ^ Cardiovascular Physiology Concepts: Mean Arterial Pressure, Richard E. Klabunde, Ph.D
2. ^ Physiology at MCG 3/3ch7/s3ch7_4
3. ^ http://www.nda.ox.ac.uk/wfsa/html/u10/u1002_03.htm