Mean Arterial Pressure (MAP)
Why Use
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.
When to Use
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.
Formula
Pearls / Pitfalls
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).
Management
Patients with a MAP that is under or above set goal values should be treated with fluids, blood products, vasopressors, inotropes, or vasodilators depending on the clinical scenario. Specific blood pressure management and MAP goals will depend on the etiology of the high or low MAP and must be individualized to optimize perfusion and prevent harm.
Critical Actions
A MAP ≥60 mmHg is believed to be needed to maintain adequate tissue perfusion. A MAP ≥65 mmHg is recommended in patients with severe sepsis and septic shock by the Surviving Sepsis Campaign Guidelines Committee .
More Information
A MAP ≥60 mmHg is believed to be needed to maintain adequate tissue perfusion. A MAP ≥65 mmHg is recommended in patients with severe sepsis and septic shock by the Surviving Sepsis Campaign Guidelines Committee.