WBR0797

Author	[[PageAuthor::Yazan Daaboul, M.D. (Reviewed by Serge Korjian)]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Physiology
Sub Category	SubCategory::Renal
Prompt	[[Prompt::A 52-year-old man presents to the physician's office complaining of headache and blurry vision. His past medical history is insignificant. The physician suspects the patient's blood pressure is elevated. In the clinic, the patient's blood pressure measures 150/70 mmHg in the right arm in sitting position. His other vital signs are as follows: Temperature 36.8 degrees C (98.2 degrees F), heart rate is 80 bpm, and respiratory rate is 14/min. What is the patient's approximate mean blood pressure?]]
Answer A	AnswerA::110 mmHg
Answer A Explanation	AnswerAExp::The mean blood pressure (MBP) is not measured by simply adding the systolic blood pressure (SBP) and diastolic blood pressure (DBP) and dividing by 2.
Answer B	AnswerB::123 mmHg
Answer B Explanation	[[AnswerBExp::This option corresponds to the following wrong equation: [2SBP+DBP]/3. It is important to remember that DBP is multiplied by 2, not the SBP.]]
Answer C	AnswerC::97 mmHg
Answer C Explanation	[[AnswerCExp::MBP = [SBP + 2DBP]/3 = 97 mmHg.]]
Answer D	AnswerD::73 mmHg
Answer D Explanation	[[AnswerDExp::This option corresponds to the following wrong equation: [SBP+DBP]/3. It is important to remember that DBP is multiplied by 2.]]
Answer E	AnswerE::Cannot be calculated
Answer E Explanation	AnswerEExp::MBP can be calculated by simply having the SBP and DBP. No additional values are needed for the equation. Other vital signs are not required either.
Right Answer	RightAnswer::C
Explanation	[[Explanation::The patient's mean blood pressure is measured as [SBP + 2DBP]/3, where SBP is the systolic blood pressure and DBP is the diastolic blood pressure. Accordingly, the patient's mean blood pressure (MBP) is [150 + (2x70)]/3 = [150+140]/3 = 97mmHg. To calculate MBP, other vital signs are not required. Educational Objective: MBP = [SBP + 2DBP]/3 References: Sesso HD, Stampfer MJ, Rosner B, et al. Systolic and diastolic blood pressure, pulse pressure, and mean arterial pressure as predictors of cardiovascular disease risk in Men. Hypertension. 2000;36(5):801-7.]]
Approved	Approved::No
Keyword	WBRKeyword::Mean blood pressure, WBRKeyword::Systolic, WBRKeyword::Diastolic, WBRKeyword::MBP, WBRKeyword::SBP, WBRKeyword::DBP, WBRKeyword::Hypertension, WBRKeyword::Blood pressure
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