Mean Arterial Pressure (MAP) of 44 mmHg: What Does It Mean?

Michael Rotman, MD, FRCPC, PhD | Medically reviewed by Robin Backlund, BHSc
Last update: February 21, 2024

What is Mean Arterial Pressure (MAP)?

Mean arterial pressure is a measure of the average pressure in a person’s arteries during one cardiac cycle. Unlike regular blood pressure, MAP only has a single value mentioned in mmHg.

It represents the average blood pressure that drives blood to all parts of the body, making it a crucial indicator of blood flow to vital organs such as the brain, kidneys, and heart.

MAP is considered a superior cardiovascular indicator to assess blood perfusion to organs than either systolic blood pressure (SBP) or diastolic blood pressure (DBP) alone, especially in critical care settings.

Even if your SBP or DBP readings appear abnormal, your MAP may still fall within the normal range.

This means that a MAP value of 44 mmHg could result from various combinations of SBP and DBP, providing a more universal metric for evaluating heart health and guiding treatment decisions.

There are several clinical benefits to using MAP assessment alongside regular blood pressure monitoring, especially in predicting the cerebrovascular impact of hypertension.

A 2023 study published in the journal Biomedicines studied the efficacy of MAP in identifying cerebrovascular events associated with hypertension with a 95.25% accuracy compared to regular blood pressure monitoring.

But the benefits don’t end there. According to NCBI’s STATPearl publication on Mean Arterial Blood Pressure and several AHA observations, below are some of the potential benefits of assessing MAP.

• Organ perfusion: MAP measures the pressure driving blood into various organs, crucial for organ function, especially in critically ill patients.
• Critical care: Monitoring MAP ensures adequate organ perfusion, which is vital for patients in shock or with severe infections.
• Treatment guide: MAP directs treatment for hypertension or hypotension, preventing organ damage.
• Cardiovascular risk: MAP predicts cardiovascular events better than other measures, especially in older adults.
• Renal function: MAP estimates renal perfusion pressure, which is crucial for kidney function.
• Cardiovascular health assessment: MAP provides a comprehensive view of cardiovascular health, aiding in diagnosis and treatment.

If MAP is an important metric, how will you calculate it? You can find out in the next section.

How do you calculate your Mean Arterial Pressure (MAP)?

There are several methods to calculate MAP, but the most popular and clinically followed one utilizes the values of systolic blood pressure (SBP) and diastolic blood pressure (DBP), following a formula also employed by Dr. Melgarejo and team in their 2020 AHA publication in the journal Hypertension.

This calculation acknowledges that the heart spends more time in diastole (when it relaxes and fills with blood) than in systole (when it contracts and pumps blood).

Therefore, MAP is not a simple average of SBP and DBP but gives more weight to the DBP.

Once you have the value, you may compare it to the reference provided by Dr. Melgarejo in his publication, as given below.

While the above method is nearly accurate, the most precise process involves an invasive procedure wherein arterial catheterization is performed to collect data directly from an artery.

There are other methods as well, elaborated below; however, they are less common and not preferred in clinical settings.

Two-thirds diastolic plus one-third systolic method

The Two-thirds diastolic plus one-third systolic method is a formula used to calculate MAP based on blood pressure readings. In this method, two-thirds of the DBP) and one-third of the SBP are added together to obtain an estimate of MAP. This formula rearranges the most frequently used calculation and emphasizes the time-weighted average of blood pressure during the cardiac cycle.

Increased heart rate estimation

At higher heart rates, the MAP is more accurately estimated by averaging the systolic and diastolic pressures due to changes in the shape of the arterial pressure pulse.

The following formula can be used for a more precise calculation of MAP during elevated heart rates.

Where PP is pulse pressure, and HR is heart rate.

Pulse pressure method

Although not a direct method for calculating MAP, understanding pulse pressure (the difference between SBP and DBP) can offer insights into MAP, especially when considering the stiffness of arteries and the workload on the heart. However, this method is more about assessing cardiovascular risk than calculating MAP directly.

If you are curious about your heart health and want to know your MAP, enter your SBP and DBP in the calculator below.

What is considered low Mean Arterial Pressure (MAP)?

A low MAP is considered to be any value less than 70 mmHg, according to the 24-hour ambulatory study by Dr. Melgarejo. However, several other studies suggest that it can go as low as 60 mmHg before becoming a point of concern.

A 2015 French study published in the journal Critical Care reports that a MAP of 60-65 mmHg is the minimum needed in patients undergoing septic shock.

This study highlights how low MAP is a sensitive metric and has a significant role in patient care.

44 mmHg is a low MAP, and people experiencing this level of blood pressure might be at risk of dizziness or fainting. Persistent low MAP might also lead to shock, which is why low MAP is always a matter of medical emergency.

Unlike a high MAP, the clinical aggravation of low MAP could be faster and decreased blood perfusion into organs, especially the brain, could be life-threatening.

Patients admitted with blood loss or infections are usually keenly observed for the MAP value in emergencies.

Even if not dangerously low, decreased mean arterial blood pressure could impair cognitive abilities in the long run.

When brain cells are deprived of glucose and oxygen for an extended period, the activity of the neurons could deteriorate, leading to memory loss, confusion, lack of concentration, etc.

You can always track your MAP using the SBP, DBP, and the above calculator. If you encounter a MAP value of 44 or less, consult your doctor.

Low MAP  could lead to various health risks and dangers, which is why you should be aware of it. Read more about it below.

What are the risks and dangers of low Mean Arterial Pressure (MAP)?

A low map of 44 mmHg can lead to several risks and dangers due to inadequate blood circulation and oxygen delivery to vital organs and tissues.

When MAP falls below the critical threshold, various physiological functions can be compromised, leading to the following.

• Organ hypoperfusion: The most immediate risk of low MAP is reduced perfusion of vital organs. Inadequate blood flow can impair the function of the kidneys, heart, brain, and other organs, leading to acute and potentially chronic conditions.
• Acute kidney injury: The kidneys are particularly vulnerable to changes in blood pressure. Low MAP can reduce renal perfusion, leading to acute kidney injury (AKI), which may result in temporary or permanent damage to kidney function.
• Cerebral ischemia: The brain relies on a constant supply of oxygen and nutrients. Low MAP can lead to inadequate cerebral perfusion, potentially causing dizziness, fainting, or, in severe cases, strokes or transient ischemic attacks (TIAs).
• Myocardial ischemia: Reduced blood flow to the heart muscle due to low MAP can lead to chest pain (angina), myocardial infarction, or heart failure, especially in individuals with underlying heart disease.
• Shock: In extreme cases, persistently low MAP can lead to various forms of shock (hypovolemic, cardiogenic, or septic), a life-threatening condition characterized by multi-organ failure and requiring immediate medical intervention.
• Lactic acidosis: Inadequate oxygen delivery to tissues can lead to anaerobic metabolism, resulting in the accumulation of lactic acid and subsequent metabolic acidosis, which can further impair organ function.

Maintaining an adequate MAP is crucial for ensuring the organs and tissues receive sufficient blood flow to function properly.

Treatment for low MAP focuses on identifying and addressing the underlying cause, such as fluid loss, heart failure, or infection, and may involve fluid resuscitation, medications to increase blood pressure, or other supportive measures, as explained below.

How do you treat low Mean Arterial Pressure (MAP)?

Treating low MAP of 44 mmHg focuses on identifying and addressing the root cause while ensuring adequate organ perfusion.

Key treatments include fluid resuscitation, typically through intravenous saline or lactated Ringer’s, to increase blood volume for cases stemming from dehydration or blood loss.

Vasopressors like norepinephrine or dopamine may be administered to constrict blood vessels and raise blood pressure, particularly when fluids are insufficient.

Inotropes, such as dobutamine, enhance the heart’s pumping efficiency, which is beneficial in heart failure scenarios.

Addressing underlying conditions is crucial; this may involve antibiotics for sepsis, specific treatments for heart conditions, or hormone replacement for endocrine imbalances.

Supportive measures, including supplemental oxygen and continuous vital signs and organ function monitoring, are integral to the treatment plan.

For individuals with chronic low blood pressure, dietary adjustments like increased salt intake and ensuring adequate hydration can be effective under medical supervision.

In extreme cases, mechanical support devices such as intra-aortic balloon pumps or ventricular assist devices might be necessary.

Treatment strategies are personalized, often requiring a multidisciplinary approach to manage the immediate issue of low MAP and any chronic conditions, ensuring the patient’s overall health and stability.