it is the lowest aortic pressure reached at the end of ventricular diastole (filling).
What is the normal range for diastolic pressure?
normally about 80 mmHg
What is systolic pressure?
it is the highest aortic pressure.
What is the normal range for systolic pressure?
normally about 120 mmHg
What is pulse pressure?
it is the difference between diastolic and peak systolic pressure in the aorta.
What is the normal range for pulse pressure?
40 mmHg
What are the two formulas for pulse pressure?
Pp = Ps - Pd
Pp = SV / Ca
What affects pulse pressure?
What doesn't affect pulse pressure?
compliance -does
mean arterial pressure
Why do we care anything about pulse pressure?
It tells us how much elastin or collagen is in the vessel.
If there is more elastin in a vessel what happens to the compliance?
more compliance- can stretch easy/more
If there is more collagen in a vessel what happens to the compliance?
less compliance- can not stretch very easy or much more
What happens to the pulse pressure as people age?
Why?
Pulse pressure tends to increase with age in adults because of a decrease in arterial compliance.
older = more stiffer = less compliance
What is the "average pressure in the aorta" called?
Mean Arterial Pressure (MAP)
What is the normal value for Mean Arterial Pressure?
100 mmHG
What two things have to do with compliance?
volume and pressure
C = change in volume / change in pressure
Why is Mean Arterial Pressure important?
It is important because it is the average effective pressure that drives blood through the systemic organs.
What is the formula for Mean Arterial Pressure?
PA = CO x TPR
What is the formula for SVR?
SVR= (MAP -CVP) / CO
What does not make a huge difference in SVR?
Central Venous Pressure (CVP)
All changes in mean arterial pressure result form what two changes?
either cardiac output or total peripheral resistance.
What two things are the same thing with the same formula?
SVR systemic vascular resistance
TPR total peripheral resistance
What is the MAP closer to diastolic pressure or systolic pressure?
it is usually closer to the diastolic pressure
MAP = 100 mmHg
diastolic = 80 mmHg
systolic =120 mmHg
Example:
If you had a normal CO of 5 Liters/min. and a normal resting total peripheral resistance of 20 mmHg/liter/min., what would the mean arterial pressure be?
PA = CO x TRP
= 5 x 20
= 100 mmHg
Example:
IF a decrease of 10 mmHg ?L?min. of the TPR and a CO of 5 L/min. will result in what mean arterial pressure?
PA = CO x TRP
= 5 x 10
= 50 mmHg
Example:
If you decrease the TPR to 10 mmHg?L?min. what would the cardiac output need to be to insure a normal mean pressure of 100 mmHg?
PA = CO x TPR
100 = CO x 10
10 = CO
CO = 10 L/min.
What is the formula for Mean Arterial Pressure including diastolic pressure and systolic pressure?
MAP or PA = PD + 1/3 (PS-PD)
What three things tend to increase with age?
1.) Pulse pressure
2.) Mean arterial pressure
3.) TPR
What two things should clinicians look at when assessing the hemodynamic status of a patient?
Why?
need to look at
1.) pulse pressure
2.) mean arterial pressure
Because diastolic pressure and systolic pressure does not tell the whole story.
Question 1
Chronic elevation of arterial pressure requires that either cardiac output or total peripheral resistance (or both) be chronically elevated?
True or False
True
PA = CO x TPR
Question 2
Whenever cardiac output is increased, mean arterial pressure must also be increased.
True or False
False
Because if TPR is decreased than MAP does not have to be increased.
Question 3
Acute increases in arterial pulse pressure usually result from increases in stroke volume.
True or False
True
Question 4
An increase in total peripheral resistance with cardiac output being constant increases diastolic pressure more than systolic pressure.
True or False
False
An increase in total peripheral resistance will increase diastolic and systolic pressures the same amount.
Question 5
Estimate the mean arterial pressure when the measured arterial pressure is 110/70 mmHg.
PA = PD + 1/3 (PS -PD)
= 70 + 1/3 (110-70)
= 70 + 1/3 (40)
= 70 + 13.33
= 83.33 mmHg
Question 6
Mean arterial pressure or PA = 100 mmHg
CVP = 0 mmHg
CO = 6 Liters/min.
What are the two formulas that can be used?
Which is considered a distractor?