Calculating the mean arterial pressure (MAP)

MAP, or mean arterial pressure, is defined as the average pressure in a patient’s arteries during one cardiac cycle. It is considered a better indicator of perfusion to vital organs than systolic blood pressure (SBP). True MAP can only be determined by invasive monitoring and complex calculations; however it can also be calculated using a formula of the SBP and the diastolic blood pressure (DBP). 

To calculate a mean arterial pressure, double the diastolic blood pressure and add the sum to the systolic blood pressure. Then divide by 3. For example, if a patient’s blood pressure is 83 mm Hg/50 mm Hg, his MAP would be 61 mm Hg. Here are the steps for this calculation:

MAP = SBP + 2 (DBP)

MAP = 83 +2 (50)

MAP = 83 +100

MAP = 183

MAP = 61 mm HG

Another way to calculate the MAP is to first calculate the pulse pressure (subtract the DBP from the SBP) and divide that by 3, then add the DBP:

MAP = 1/3 (SBP – DBP) + DBP

MAP = 1/3 (83-50) + 50

MAP = 1/3 (33) + 50

MAP = 11 + 50

MAP = 61 mm Hg

There are several clinical situations in which it is especially important to monitor mean arterial pressure. In patients with sepsis, vasopressors are often titrated based on the MAP. In the guidelines of the Surviving Sepsis Campaign, it is recommended that mean arterial pressure (MAP) be maintained ≥ 65 mm Hg. Also, in patients with head injury or stroke, treatment may be dependent on the patient’s MAP. 

In what other clinical situations do you monitor MAP?  

Surviving Sepsis CampaignAccessed December 8, 2011. 
Smeltzer, S. C., Bare, B. G., Hinkle, J. L., & Cheever, K. H. (2010). Brunner & Suddarth's Textbook of Medical-Surgical Nursing, Twelfth Edition. Philadelpha: Wolters Kluwer Health/ Lippincott Williams & Wilkins.

More Reading & Resources
Focus On: Sepsis
Focus On: Stroke


Posted: 12/8/2011 8:49:14 PM by Lisa Bonsall, MSN, RN, CRNP | with 14 comments

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11/7/2017 4:46:17 PM

river ranch
So, why can’t we use this same formula to calculate the MAP at home using the SBP checking equipment? I read that MAP is more important than SBP and gives vital information regarding your health. So, I think we should be checking MAP rather than SBP.
9/15/2017 6:54:26 AM

Jeetender kumar meena
Full information of map
8/9/2017 12:22:16 AM

Jeetender kumar meena
Sir i want full information of MAP and what is map and how to check map
8/9/2017 12:20:29 AM

mmiriaku Nwudoh
Great work, made my study very easy.
5/24/2017 9:56:09 PM

Mathew Adegbaju
Thanks for this educative information.
5/2/2017 11:47:06 PM

Here is a mechanical/cycle way of explaining how the above formula is determined. It works every time
1/3/2017 5:48:41 PM

Carmen Demorizi
Thank you for this information
11/29/2016 6:46:38 PM

Hillary Hunt, RN
This was extremely helpful. Thank you.
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10/16/2015 12:30:57 PM