Mean Arterial Pressure (MAP)
- The Mean Arterial Pressure can be calculated in all patients in which blood pressure values are obtained.
- Blood pressure targets have been shown to improve outcome in a number of conditions. These include sepsis, trauma, stroke, intracranial bleed, and hypertensive emergencies.
- Clinical guidelines may use either SBP or MAP as a blood pressure goal.
- The Mean Arterial Pressure (MAP) is derived from a patient’s Systolic Blood Pressure (SBP) and Diastolic Blood Pressure (DBP).
- MAP is often used as a surrogate indicator of blood flow and believed to be a better indicator of tissue perfusion than SBP as it accounts for the fact that two thirds of the cardiac cycle are spent in diastole.
- A MAP of 60 mmHg or greater is believed to be needed to maintain adequate tissue perfusion.
- Since MAP is a product of Cardiac Output (CO) and Systemic Vascular Resistance (SVR) [MAP = CO x SVR], variations in SVR make the relationship between MAP and CO often unreliable (for example, a patient with a poor CO but high SVR such as a patient in cardiogenic shock may have an acceptable MAP but a CO that is too low to provide adequate perfusion to tissues).
The MAP should be calculated when the clinical scenario mandates a blood pressure adjustment based on MAP rather than SBP, as well as for the management of patients with acute conditions where there is a concern for appropriate organ perfusion.
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About the Creator
Sheldon Magder, MD, is a critical care physician at Royal Victoria Hospital and a professor in the Department of Physiology at McGill University in Montreal, Canada. His research is in cardiovascular physiology, specifically regulation of vascular tone in sepsis, the effects of the estrogens on the vascular wall and control and distribution of peripheral blood flow in exercise, heat stress and shock.
To view Dr. Sheldon Magder's publications, visit PubMed