Mean Arterial Pressure (MAP) is an important physiological measure that provides an estimate of the average blood pressure in a person's arteries during one cardiac cycle. It assesses the perfusion pressure experienced by organs, making it crucial in critical care settings.
The correct formula for calculating MAP is:
MAP = DBP + (SBP - DBP) / 3
This can also be simplified and expressed in a slightly different form:
MAP = (2 x DBP + SBP) / 3
In more practical terms, the common interpretation used in practice is that it effectively averages the contributions of systolic and diastolic blood pressures, where diastolic pressure is typically weighted more heavily because the heart spends more time in diastole than in systole.
Choosing the formula that recognizes this weighting accurately reflects the continuous pressure that the organs are subjected to throughout the cardiac cycle, which directly correlates with organ perfusion and overall hemodynamic stability. This is why the initial choice of summing the diastolic pressure with an adjusted contribution from the systolic pressure provides a meaningful and applicable measure of MAP.