Name ____________________________
Hemodynamics Practice Problems
Per ___
Write-out the hemodynamics equation here:
Basics:
HR = heart beats per min (beats/min)
SV = stroke volume = amount of blood ejected by the ventricles of the heart per beat (mL/stroke)
CO = cardiac output = HR X SV (mL/min)
PVR = peripheral vascular resistance = resistance of outermost blood vessels
vessel description
correct term
resistance to flow
patient looks…
why?
High PVR:
clamped-down
vasoconstricted
high resistance
pale
shunt blood to core
Low PVR:
wide open
vasodilated
low resistance
flushed
bring blood to skin surface
Use the following starting values for the following scenarios:
HR = 60
1.
SV = “norm”
PVR = “norm”
BP = 120/80
A person at rest ingests caffeine (a stimulant), causing the HR to climb. What is the immediate
effect on the BP?
2. A person at rest is having a heart attack, specifically a posterior wall MI (myocardial infarction),
affecting the sinoatrial node in the right atrium and causing the HR to drop. What is the
immediate effect on the BP?
3. A person at rest takes the heart medication Digoxin (lanoxin), causing the stroke volume to
increase. What is the immediate effect on the BP?
4. A person at rest takes the heart medication Cardizem (diltiazem), causing the stroke volume to
decrease. What is the immediate effect on the BP?
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5. A person takes cocaine (a vasoconstrictor).
a. What is the immediate effect on PVR?
b. What is the immediate effect on BP?
6. A person sustains a spinal cord injury, causing peripheral vasodilation.
a. What is the immediate effect on PVR?
b. What is the immediate effect on BP?
Now, let’s examine the homeostatic mechanisms in place to maintain a “normal” blood pressure.
Remember, the goal of BP homeostasis is to MAINTAIN A “NORMAL” BLOOD PRESSURE.
7. A patient has taken too much Metoprolol (this is a 1–blocker, which means that it blocks
receptors on the heart responsible for heart rate), causing their heart rate to drop.
a. What two factors can compensate for this drop in HR? How will they compensate?
b. What will the patient look like?
8. A patient has taken a stimulant that increases the force of cardiac contraction, thereby
increasing stroke volume.
a. What two factors can compensate for this increase in SV? How will they compensate?
b. What will the patient look like?
9. A patient with mono who has not yet been medically cleared plays football and sustains a
lacerated spleen (in the LUQ). Stroke volume has dropped because there is no longer as much
blood in the blood vessels.
a. What two factors can compensate for this drop in SV? How will they compensate?
b. What will the patient look like?
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10. A tennis player has a sinus infection and is taking a decongestant containing pseudoephedrine.
This is a potent vasoconstrictor.
a. What is the effect on PVR?
b. What two factors can compensate for this change in PVR? How will they compensate?
c. What will the player look like?
11. You are the athletic trainer at a soccer game. You have just been notified that a spectator has
been stung by a bee and is having an allergic reaction. As part of the immune response, mast
cells near the bite site are releasing histamine, a potent vasodilator.
a. What is the effect on PVR?
b. What two factors can compensate for this change in PVR? How will they compensate?
c. What will the player look like?
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