Cardiovascular calculations: Peter is wearing a cardiovascular monitoring device
ID: 3476026 • Letter: C
Question
Cardiovascular calculations: Peter is wearing a cardiovascular monitoring device during his rowing competition. He is at the 1000 meter mark (halfway through), and his device is reading the following data: PARAMETER Systolic pressure (aorta) Diastolic pressure (aorta) R-R interval Left ventricular EDV Left ventricular ESV Mean pulmonary artery pressure Right atrial pressure Left atrial pressure O2 consumption (whole body) O2 content of systemic arterial blood O2 content of pulmonary arterial blood VALUE 170 mm Hg 80 mm Hg 470 msec 180 mL 50 mL 21 mmHg 3 mm Hg 6 mmHg 1500 mL/min 0.20 mL O2/mL blood 0.11 mL O2/mL bloodExplanation / Answer
1. Mean arterial pressure (MAP) cannot be calculated by simply taking the average of SYSTOLIC and DIASTOLIC blood pressure because averaging SBP and DBP does not take the fact into account that a greater fraction of each cardiac cycle, APPROXIMATELY 2/3rd is spent in DIASTOLE. Thus MAP is more close to DIASTOLIC BLOOD PRESSURE than SYSTOLIC.
MAP = I/3 (SBP-DBP)+DBP
MAP=1/3 (170mmHg - 80mmHg) + 80 mmHg
MAP = 1/3 ( 90mmHg) + 80mmHg
MAP = 30mmHg + 80mmHg
MAP = 110mmHg.