Equations

Question 1

Cardiac Output

Answer 1

CO = SV {stroke volume} x HR {heart rate}

Question 2

Blood Pressure

Answer 2

BP = CO {Cardiac Output} x TPR {total peripheral resistance}

Question 3

Cardiac Output (O2)

Answer 3

CO = O2 consumption / (Pulmonary Vein [O2] - Pulmonary artery [O2])

Question 4

Velocity

Answer 4

V = Q {flow} / A {cross sectional area; Pi*r^2}

Question 5

Flow

Answer 5

Q = Delta P {change in pressure} / R {resistance}

Think of Ohm’s law (I = V/R)

Question 6

Resistance (Poiseuille’s Equation)

Answer 6

R = (8 * n {viscocity} * l {length}) / (Pi * r^4)

Question 7

Total Peripheral Resistance

Answer 7

TPR = (PA {pressure aorta} - PV {pressure vena cava}) / CO {cardiac output}

Question 8

Cardiac Output (Pressure)

Answer 8

CO = (PA {pressure aorta} - PV {pressure vena cava} / TPR {total peripheral resistance}

Question 9

Total Resistance (series)

Answer 9

RT = R1 + R2 +R3 + etc

Question 10

Total Resistance (parallel)

Answer 10

1/RT = 1/R1 + 1/R2 + 1/R3 + etc

Question 11

Compliance

Answer 11

C = V {volume} / P {pressure}

Compliance is the ability of a vessel to lose its shape as blood volume increases.

Question 12

Fluid Movement (Starling equation)

Answer 12

Jv = Kf {filtration coefficient} [(Pc {capillary hydrostatic pressure} - Pi {interstitial hydrostatic pressure}) - (pi.c {capillary oncotic pressure} - pi.i {interstitial oncotic pressure})]

Question 13

Tension (law of LaPlace for cylinder)

Answer 13

T = P {pressure} * r {radius}

Question 14

Mean Arterial Pressure

Answer 14

MAP = CO {cardiac output} * TPR {total peripheral resistance}

OR

MAP = HR {heart rate} * SV {stroke volume} * TPR {total peripheral resistance}

Question 15

Ejection Fraction

Answer 15

EF = SV {stroke volume} / EDV {end diastolic volume}

EF = (EDV {end diastolic volume} - ESV {end systolic volume}) / EDV {end diastolic volume}

Question 16

Pulse Pressure

Answer 16

PP = Systolic Pressure - Diastolic Pressure

Determined by the Stroke Volume