Mean Arterial Pressure (MAP)

I'm currently studying shock, its a huge subject and incredibly important topic in medicine. It doesn't matter what kind of doctor you are, you need to be able to deal with shock. MAP is very relevant in the state of shock.

MAP a great indicator of the perfusion pressure of the organs. Its kind of like an average blood pressure, so if its low there isn't much blood reaching the vital organs. As we all know, blood pressure has two components a systolic and diastolic component. So its not so easy to work out MAP or 'average' blood pressure.

There are some formulas that help (DBP = diastolic blood pressure, SBP = systolic blood pressure):

MAP = DBP + 1/3 (DBP-SBP)

MAP = 2/3 DBP + 1/3 SBP

There are many and quick search of wikipedia or on google will easily come up with many different formules, the two above are the simplest. (note: DBP - SBP is also called the Pulse Pressure).

A normal MAP in a healthy subject is around 90mmHg or in the range 70-110mmHg,
In the treatment of shock we are trying to get the MAP to around 65mmHg or maintaining it there.
(this is because a MAP above 60mmHg is considered enough to perfuse the organs. thus below 60mmHg you should start worrying about organ ischemia).