Equations: Cardiovascular System

Question 1

Cardiac Output

Answer 1

CO = SV x HR

Question 2

Ejection Fraction

Answer 2

EF = (EDV - ESV)/EDV = SV/EDV

EDV = end diastolic volume

ESV = end systolic volume

Question 3

Stroke volume

Answer 3

`SV = EDV - ESV

Question 4

Compliance

Answer 4

Compliance = ΔV/ΔP

ΔV = change in volume

ΔP = change in pressure

Question 5

Velocity of Blood Flow

Answer 5

v= Q/A

v = velocity (linear)

Q = flow

A = cross-sectional area

Question 6

Resistance

Answer 6

Resistance = ΔP/Q

ΔP = change in pressure

Q = volume flow

Question 7

Poiseuille’s Law

Answer 7

Question 8

Total Peripheral Resistance (TPR)

Answer 8

TPR = ΔP/Q

ΔP = change in pressure across the circuit or organ

Q = volume flow

Question 9

Blood Pressure

Answer 9

BP = CO x Peripheral Resistance

Question 10

Starling’s Equation

Answer 10

Fluid Movement (Ultrafiltration) = k[(P_c + π_i) - (P_i + π_p)

P_c = capillary hydrostatic pressure

P_i = interstitial fluid hydrostatic pressure

π_p = plasma protein oncotic pressure

π_i = interstitial fluid oncotic pressure

k = filtration constant for the capillary membrane

Question 11

Mean Arterial Blood Pressure (maBP)

Answer 11

maBP = diastolic + ⅓ PP

diastolic = bottom of BP (lower pressure)

PP = pulse pressure

Question 12

Pulse Pressure (PP)

Answer 12

Systolic - Diastolic

if BP = 120/80 → PP = 40