If diastolic blood pressure is 78 mm Hg and systolic blood pressure is 186 mm Hg, what is mean arterial pressure? 132 mmHg 120 mmHg 93.3 mmHg 114 mmHg
The Correct Answer and Explanation is:
Correct Answer: 114 mmHg
Explanation:
To calculate the Mean Arterial Pressure (MAP), use the standard formula:MAP=Diastolic BP+13(Systolic BP−Diastolic BP)\text{MAP} = \text{Diastolic BP} + \frac{1}{3}(\text{Systolic BP} – \text{Diastolic BP})MAP=Diastolic BP+31(Systolic BP−Diastolic BP)
Given:
- Systolic Blood Pressure (SBP) = 186 mm Hg
- Diastolic Blood Pressure (DBP) = 78 mm Hg
First, calculate the pulse pressure:Pulse Pressure=SBP−DBP=186−78=108 mm Hg\text{Pulse Pressure} = \text{SBP} – \text{DBP} = 186 – 78 = 108 \text{ mm Hg}Pulse Pressure=SBP−DBP=186−78=108 mm Hg
Now insert values into the MAP formula:MAP=78+13(108)=78+36=114 mm Hg\text{MAP} = 78 + \frac{1}{3}(108) = 78 + 36 = 114 \text{ mm Hg}MAP=78+31(108)=78+36=114 mm Hg
Thus, the Mean Arterial Pressure is 114 mm Hg.
Clinical Relevance:
Mean Arterial Pressure represents the average pressure in a person’s arteries during one cardiac cycle. It reflects the perfusion pressure seen by organs in the body, especially the brain and kidneys. A MAP between 70 and 100 mm Hg is considered adequate to sustain the organs of the average person. A MAP lower than 60 mm Hg may indicate insufficient blood flow to vital organs, while a MAP consistently over 110 mm Hg may increase the risk of vascular damage and organ strain.
In this case, a MAP of 114 mm Hg suggests elevated pressure and could indicate hypertension, particularly since the systolic value (186 mm Hg) is markedly high. Such values warrant medical evaluation to assess cardiovascular risk and consider therapeutic management.
This calculation is particularly useful in critical care, anesthesia, and cardiology to monitor and adjust therapy, especially when blood pressure is unstable.
