Learn › Mean arterial pressure (MAP)
How to calculate mean arterial pressure (MAP)
Mean arterial pressure (MAP) is the average pressure in the arteries over one heartbeat. Calculate it as (systolic + 2 × diastolic) ÷ 3; a normal MAP is about 70 to 100 mm Hg, and a MAP of at least 65 mm Hg is the usual target in septic shock.
The formula
- MAP = (systolic + 2 × diastolic) ÷ 3
- Same thing, another way: MAP = diastolic + one third of the pulse pressure (systolic minus diastolic).
- Diastole counts twice because the heart spends about two thirds of each beat relaxing.
Worked examples
| Blood pressure | Math | MAP |
|---|---|---|
| 120/80 | (120 + 160) ÷ 3 | 93 mm Hg |
| 90/50 | (90 + 100) ÷ 3 | 63 mm Hg (low) |
| 150/90 | (150 + 180) ÷ 3 | 110 mm Hg (high) |
What the numbers mean
- About 70 to 100 mm Hg: normal.
- Below about 60 mm Hg: organs such as the brain, heart and kidneys may not get enough blood.
- 65 mm Hg or higher: the usual starting target for clients with septic shock.
- Many monitors show the MAP automatically in parentheses next to the blood pressure.
When the MAP is low
- Recheck the blood pressure and look at the client: mental status, skin, urine output.
- Notify the provider.
- Expect fluids first in hypovolemia or sepsis, then vasopressors as ordered if the MAP stays low.
- Titrate vasopressors to the MAP goal in the order and watch the IV site closely.
NCLEX tip: A normal systolic pressure can hide a low MAP if the diastolic is very low. When an order says "titrate to MAP of 65 or more", use the MAP, not the systolic.
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Frequently asked questions
What is a normal MAP?
About 70 to 100 mm Hg in adults.
What MAP is needed to perfuse the organs?
At least about 60 mm Hg. In septic shock, the usual target is 65 mm Hg or higher.
What is the MAP of 120/80?
(120 + 2 × 80) ÷ 3 = 93 mm Hg.
What is the MAP for 120/80?
About 93 mm Hg. Using MAP = (systolic + 2 × diastolic) ÷ 3: (120 + 160) ÷ 3 = 93.
What is the formula for the MAP?
MAP = (systolic + 2 × diastolic) ÷ 3. Another way: diastolic plus one third of the pulse pressure. A normal MAP is about 70 to 100 mm Hg.
Can you calculate a MAP from BP?
Yes. MAP = (systolic + 2 × diastolic) ÷ 3. For a BP of 120/80, the MAP is (120 + 160) ÷ 3 = 93 mm Hg.
Keep studying
Sources
- Physiology, Mean Arterial Pressure, StatPearls, NCBI Bookshelf
- Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock 2021, Society of Critical Care Medicine
For study only, not medical advice. Ranges and protocols vary by facility; follow your program, your facility's policies and the provider's orders.