From the Guidelines
MAP stands for Mean Arterial Pressure, which is the average blood pressure in a person's arteries during one cardiac cycle, calculated using the formula: MAP = [(2 × diastolic pressure) + systolic pressure] ÷ 3, with a normal range of 70-100 mmHg in adults, as supported by various studies 1.
Definition and Calculation of MAP
MAP is a crucial measurement in clinical settings, representing the perfusion pressure needed to maintain adequate blood flow to vital organs. It is often monitored continuously in intensive care units to guide treatment decisions for hemodynamically unstable patients. The formula gives more weight to diastolic pressure because the heart spends about two-thirds of the cardiac cycle in diastole.
Clinical Importance of MAP
Healthcare providers use MAP rather than just systolic and diastolic readings when managing critically ill patients, particularly those with shock or requiring vasopressor medications. MAP below 65 mmHg for extended periods can lead to organ damage due to insufficient perfusion, while consistently elevated MAP indicates hypertension requiring treatment. According to recent guidelines, a mean arterial pressure target of 65 mm Hg is recommended in septic shock and general ICU patients 1.
Key Points to Consider
- MAP is calculated using the formula: MAP = [(2 × diastolic pressure) + systolic pressure] ÷ 3.
- A normal MAP ranges from 70-100 mmHg in adults.
- MAP is clinically important for managing critically ill patients, particularly those with shock or requiring vasopressor medications.
- MAP below 65 mmHg for extended periods can lead to organ damage, while consistently elevated MAP indicates hypertension requiring treatment.
- Recent guidelines recommend a mean arterial pressure target of 65 mm Hg in septic shock and general ICU patients 1.
From the Research
Definition of MAP
- Mean Arterial Pressure (MAP) refers to the average of the arterial blood pressure through a single cardiac cycle 2
- It can be an alternative index that may capture the overall exposure of the person to a heightened pressure 2
Clinical Significance of MAP
- MAP may be more beneficial and accurate in identifying the cerebrovascular impact of hypertension than just using either systolic BP or diastolic BP 2
- A clinical hypothesis suggests that in patients over 50 years old, systolic BP may be more predictive of adverse events, while in patients under 50 years old, diastolic BP may be slightly more predictive 2
- MAP is used as a target in various clinical trials, such as the MAP-CARE trial, which aims to investigate the influence of MAP targets on patient outcomes after cardiac arrest and resuscitation 3
MAP in Clinical Trials
- The MAP-CARE trial is designed to test the hypothesis that targeting a higher MAP (>85 mmHg) versus a lower MAP (>65 mmHg) after resuscitation from cardiac arrest reduces 6-month mortality 3
- Other studies have investigated the effects of different antihypertensive drug combinations on blood pressure and arterial stiffness, with MAP being one of the measured outcomes 4, 5, 6
- These studies suggest that MAP is an important parameter in the management of hypertension and its complications 4, 5, 6