Looking for more details? Read our comprehensive MAP guide
What is Mean Arterial Pressure (MAP)?
Mean Arterial Pressure (MAP) is 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) alone.
Formula
Standard Reference Ranges
- Low (Hypoperfusion risk) < 65 mmHg
- Normal/Target 65 – 100 mmHg
- High (Hypertension risk) > 100 mmHg
Clinical Significance
A MAP of at least 65 mmHg is generally necessary to maintain adequate tissue perfusion to vital organs, such as the brain, coronary arteries, and kidneys. In conditions like sepsis or shock, targeting a MAP ≥ 65 mmHg is a standard resuscitation goal.
Case Scenario
Patient: A 65-year-old patient in the ICU with suspected sepsis has a blood pressure of 90/50 mmHg.
Calculation: MAP = (90 + 2 × 50) / 3 = 190 / 3 = 63.3 mmHg
Interpretation: The MAP is below the target of 65 mmHg, indicating inadequate perfusion.
Next Steps: Administer IV fluids or vasopressors to increase the MAP to ≥ 65 mmHg.
Frequently Asked Questions
At normal resting heart rates, the heart spends approximately two-thirds of the cardiac cycle in diastole (relaxation and filling) and one-third in systole (contraction). Therefore, the diastolic pressure contributes twice as much to the mean pressure.
At higher heart rates (e.g., tachycardia), diastole shortens significantly. In such cases, the true MAP measured directly via an arterial line may differ from the calculated MAP, as the 1/3 and 2/3 ratio no longer applies perfectly.
References
- Evans LD, et al. Surviving sepsis campaign: international guidelines for management of sepsis and septic shock 2021. Intensive Care Med. 2021.
- DeMers D, Wachs D. Physiology, Mean Arterial Pressure. [Updated 2023 Apr 10]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-.
How to Use
Enter the patient's systolic and diastolic blood pressure. The tool calculates the Mean Arterial Pressure, an indicator of tissue perfusion.