What is mean arterial pressure?

Automatic blood pressure monitors give you a systolic and diastolic blood pressure reading. Many of them also include a small number in parentheses underneath or beside your standard blood pressure reading. This number in parentheses is the mean arterial pressure (MAP).

MAP is a calculation that doctors use to check whether there’s enough blood flow, resistance, and pressure to supply blood to all your major organs.

“Resistance” refers to the way the width of a blood vessel impacts blood flow. For example, it’s harder for blood to flow through a narrow artery. As resistance in your arteries increases, blood pressure also increases while the flow of blood decreases.

You can also think of MAP as the average pressure in your arteries throughout one cardiac cycle, which includes the series of events that happen every time your heart beats.

What is a normal MAP?

In general, most people need a MAP of at least 60 mmHg (millimetres of mercury) or greater to ensure enough blood flow to vital organs, such as the heart, brain, and kidneys. Doctors usually consider anything between 70 and 100 mmHg to be normal.

A MAP in this range indicates that there’s enough consistent pressure in your arteries to deliver blood throughout your body.

What is a high MAP?

A high MAP is anything over 100 mmHg, which indicates that there’s a lot of pressure in the arteries. This can eventually lead to blood clots or damage to the heart muscle, which has to work a lot harder.

Many things that cause very high blood pressure can also cause a high MAP, including:

·                    heart attack

·                    kidney failure

·                    heart failure

What is a low MAP?

Anything under 60 mmHg is usually considered a low MAP. It indicates that your blood may not be reaching your major organs. Without blood and nutrients, the tissue of these organs begins to die, leading to permanent organ damage.

Doctors usually consider a low MAP to be a possible sign of:

·                    sepsis

·                    stroke

·                    internal bleeding

How is an unusual MAP treated?

An unusual MAP is usually a sign of an underlying condition or problem in the body, so the treatment depends on the cause.

For a low MAP, treatment focuses on safely raising blood pressure quickly to avoid organ damage. This is usually done with:

·                    intravenous fluids or blood transfusions to increase blood flow

·                    medications called “vasopressors” that tighten blood vessels, which can increase blood pressure and make the heart beat faster or pump harder

Treating a high MAP also requires quick action, in this case, to reduce overall blood pressure. This can be done with oral or intravenous nitroglycerin (Nitrostat). This medication helps to relax and widen blood vessels, making it easier for blood to reach the heart.

Once the blood pressure is under control, the doctor can begin treating the underlying cause. This might involve:

·                    breaking up a stroke-causing blood clot

·                    inserting a stent into a coronary artery to keep it open

The bottom line

MAP is an important measurement that accounts for flow, resistance, and pressure within your arteries. It allows doctors to evaluate how well blood flows through your body and whether it’s reaching all your major organs.

Most people do best with a MAP between 70 and 110 mmHg. Anything much higher or lower can be a sign of an underlying problem.