Normal Values for Cardiovascular Parameters

Systolic blood pressure

SBP in mmHg

Is the max arterial pressure generated by the ventricles during systole

SBP= 120 (normal range 90-139mmHg)

Diastolic blood pressure

DBP in mmHg

arterial pressure during ventricular diastole; result of/maintained by elastic arteries

DBP=80mmHg (normal range=60-89)

Pulse pressure

PP in mmHg

PP (SBP-DBP) = 120 - 8= 40 (normal range: 20-60)

End diastolic volume

EDV in mL/beat

volume (mL) in ventricles at the end of ventricular diastole

EDV (ESV+SV) = 30+70 = 100mL/beat

normal resting range is 60-120, but greatly depends on level of exertion and cardiac work

End systolic volume

ventricular volume at the end of ventricular systole

ESV in mL/beat

ESV (EDV-SV) = 100 - 70 = 30 mL

normal resting range is 20 -50 but most people are normally around 30 as it is highly regulated

Stroke volume

volume pumped by the ventricle per beat

SV in mL/beat

SV (EDV-ESV) = 100 mL/beat - 30mL = 70mL/beat

normal resting range is 50-120, but can increase over 5x with exercise

Ejection fraction

Percentage of blood in ventricle that is pumped out

EF in %

EF (SV/EDV x 100) = 70mL/beat / 100mL x 100 = 70%

Normal resting range is 50 - 80

Heart Rate

HR in beats/min

HR = 74 BPM

Normal is 60-100 BPM

Cardiac output

CO in mL/min

Volume of blood pumped by heart in a given amount of time

CO = (HRxSV) = 74BPM x 70mL = 5180mL/min

Normal range is 4000 - 8000 mL, often cited as 5 - 5.5 LTo

Total Peripheral Resistance

TPR is best estimated using Poiseuille’s law

TPR = 0.01801 min x mmHg/mL

Normal range is 0.005 - 0.020

Mean arterial pressure

MAP

• 93.3 mmHg

• Normal range: 70 - 110

=( 1/3 SBP + 2/3 DBP)

= (1/3 PP + DBP)

= (HRxSVxTPR)

= (COxTPR)

Total peripheral resistance (TPR) is best approximated by Poiseuille's law:

R = 8Lxn/r where L = tube length. n = viscosity and r = radius of the vessel. While all factors have physiological significance, the most important variable in terms of control is the radius of the vessel (r) by far. This is because radius is raised to the fourth power in terms of the equation so that small changes in radius have huge effects on resistance and therefore flow. In addition, this variable can be manipulated to change very quickly, while the others have a much longer time for change.

Pressure = flow x resistance (P = QR)

so if either flow (Q) or resistance (R) goes up, then pressure will go up. This is the same equation in general as the MAP = Q x TPR equation, but just more general.

Flow = pressure/resistance (Q = P/R)

if we replace R with Poiseuille's law then Q = p x r/8L x n. Thus, flow (Q) is directly proportional to changes in pressure (P) and radius (r), meaning if either of those two variables increase, then flow increases. However, flow (Q) is inversely proportional to tube length (L) and viscosity (n). If either of those variables increase, then flow will be diminished.

The Ohmic Relationship of Pressure (P), Flow (Q) and Resistance (R):

Pressure = flow x resistance

P = Q x R

Q = P / R

R = P / Q

Ohm’s law states that V=IR (voltage = current x resistance), which relates to electricity, may be modified to understand the

circulatory system through what is often referred to as the Ohmic relationship. This is accomplished by replacing voltage

with pressure, and current with flow, where cardiac output (Q) = flow. Then, P = Q x R. It follows, then, because Q = P/R,

that flow and resistance are inversely proportional.

Poiseuille’s Law:

R = L x n / r4 - but since the 8 is just a constant, we can remove the 8 and retain proportionality from (8L x n / r4)

Poiseuille’s law describes resistance (R) in tubes. As tube length (L) and or viscosity (n) increases, so does R. They are

directly proportional to resistance. However, radius (r) (radius is used for the purposes of the equation and is half the

diameter) is inversely proportional to resistance such that as radius increases, the resistance goes down.

Detailed Flow Equation:

Q = P x r4 / L x n - flow equals pressure / resistance (Q = P / R), so it follows by inserting 1 / R for resistance in the equations we get: Q = P x r4 / L x n.