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78 Cards in this Set

  • Front
  • Back
What is normal SBP/DBP?
How does bp change in Arteriosclerosis?
Systolic BP increases mostly
How does bp change in arteriosclerosis?
Pulse pressure is decreased due to a very low systolic bp
Why does Aortic stenosis cause a reduced pulse pressure?
Because the valve is stiff and less blood is ejected
What are 2 conditions where pulse pressure is increased due to both increased SBP and decreased DBP?
-Aortic regurgitation
How do you most accurately measure pulse pressure?
By catheterization
What is the "Windkessel effect"?
The role of the elasticity of the aorta and large vessels to absorb the pulsatile volume and move bloodflow forward from the heart.
What happens to pulse pressure as the pulse wave travels from large to smaller arteries?
It gets dampened
What are the 2 reasons for pulse damping?
1. Vascular resistance
2. Vascular compliance
So what IS damping?
The product of resistance and compliance
What happens BP in most people as they age?
It increases - particularly Systolic BP
Is increasing BP with age normal?
NO - it just shows that lots of old people have diseased vessels.
How do you calculate MAP?
MAP = ---------
Why are Veins extremely important? (2 reasons)
1. They can constrict/enlarge, so can store & make blood available quickly
2. They return blood to the heart, which is necessary for CO
What is the balance that regulates RAP?
1. RH's ability to pump out
2. Tendency for blood to flow INTO the right heart via veins
What is normal RAP?
0 mm Hg
What is RAP in a failing heart?
20-30 mm Hg
What is RAP when the heart is pumping vigorously but venous return is limited?
-3 to -5 mm Hg
Why is it important to realize that the veins are blood reservoirs?
Because where the blood is determines what CO will be
What happens to blood on a very hot day?
It pulls in the venous plexus of the skin to help cool the body.
What happens to CO as a result of veinous pooling in skin veins on a hot day?
CO decreases a lot due to decrease veinous return
Where are the veins most prone to collapse?
In the thorax
What is the avg pressure in the peripheral veins?
ABout 4-6 mm Hg higher than in the Right atrium
What happens to your blood as you stand in the same place for a long time?
It pulls in your veins
What is veinous pressure at
-The feet
-Sagittal sinus
Feet = 90 mm Hg
Sagittal Sinus = -10 mm Hg
What is arterial pressure at the feet?
190 mm Hg
Why is arterial pressure so high in the feet?
Due to the weight of that column of blood under gravitational pressure, pressing down.
Why doesn't blood normally pool in lower extremities and balloon out the veins?
Because the veins act as a pump to return blood back to the heart!
What happens to the pressure gradient in your vessels when you lie down?
It goes away!
Why do we say bp in the brain is NEGATIVE?
Because the heart is the reference zero level
What ALLOWS the veins to act as blood pumps to return it to the heart? (3 things)
1. Valves
2. Leg muscles
3. Leg movement
What would happen if our leg veins did not have valves?
The veins in our feet would have a pressure of 90 mm Hg
What happens if there is no leg movement?
The capillary pressure in legs elevates results in increased filtration of plasma fluid.
How much of the blood volume can seep into the leg interstitium with only 15 minutes of standing still?
What is the most direct way to measure pressure in a vessel?
How do you measure pressure in the left heart?
By introducing a catheter into the brachial/femoral artery and pass it retrograde into the ventricle.
How do you know when you get to the left ventricle?
Because of the pressure drop
-Aorta = 120/80
-LV = 120/5
How do you measure pressure in the right heart?
1. Introduce catheter into vein
2. Advance into the right atrium
3. Detect RAP of 0
How do you measure pulmonary artery pressure?
Push the catheter through the right ventricle into the pulmonary artery
What do you measure when you push a catheter through the right ventricle and pulmonary artery until you can't push it anymore?
Pulmonary wedge pressure
What is the most common way to measure blood pressure?
By the Auscultatory method
What is the basis for the Auscultatory method?
The fact that you can HEAR bloodflow
What happens as you increase the cuff pressure?
You're increasing transmural pressure until the artery collapses.
What do you hear when the artery collapses?
What happens as you deflate the cuff?
You decrease transmural pressure until the point where the systolic pressure in the vessel is able to flow through the weakening constriction again.
What is the difference in quality of the Systolic and diastolic pressure?
Systolic = sharp/tapping
Diastolic = Muffled
What are the sounds generated by the auscultatory method called?
Korotkoff sounds
What is the reference point for circulatory pressure measurement? Why?
The triscupid valve - because this level is relatively independent of body position - gravity has little effect on pressure here.
What is another method for indirect BP measurement other than Auscultatory?
What is the basis of Oscillometric measurement?
Doppler - using an ultrasonic transducer to detect movement of the arterial wall
Why is radio-opaque fluoroscopy used during catheterization for direct pressure measurements?
To be able to see where the catheter is as you're inserting it.
What should Right atrial pressure be?
About 0 mm Hg
What is the normal SBP/DBP in the right ventricle?
20/0 mm Hg
What is the normal pulmonary artery pressure?
20/5 mm Hg
What is the normal Pulmonary wedge pressure?
5-10 mm Hg
What is the normal Left Atrial pressure?
5-10 mm Hg!
What is the normal Left Ventricular Pressure?
What is the normal aortic pressure?
What is Pulmonary wedge pressure used to determine? Why?
Left atrial pressure - because left heart catheterization is much riskier and this allows for accurate measurement.
What is a common way to measure cardiac output?
What is the basis of thermodilution?
You inject a really cold substance and measure its flow past a temp sensor; the temp gradient is plotted; the area of deviation is proportional to Cardiac output.
What is the drawback of the thermodilution method?
It only measures cardiac output at that one moment in time; CO changes constantly so it's not necessarily really accurate.
So the two dilution principle methods for measuring CO are:
-Dye dilution
What is the more common and easier way to measure CO?
Fick's principle
What is the normal O2 content in the blood in the veins? Arteries?
Veinous Content O2 = 160 ml/L
Arterial Content O2 = 200 ml/L
How much oxygen is normally taken up at the lungs?
200 ml/min
So how do you calculate CO using Fick's principle?
Q160 + 200 = Q200

Q = 200/40 = 5L/min
What is Intra-aortic balloon pumping?
A way to support circulation by putting a balloon into the aorta
-During systole deflate
-During diastole inflate
How is Intra-aortic balloon pumping done? What is its result?
-During systole deflate
-During diastole inflate
-Just as systole starts, suck air into balloon, pulling blood into the left ventricle.
What is the major effect of Intra-aortic balloon pumping?
Decreases afterload - makes it negative, and makes it easier for the heart to pump.
What is Radionuclide imaging used to measure?
Heart function
What do you know if the heart doesn't take up radiolabeled isotope?
It's ischemic
What is a totally noninvasive way to measure cardiac function?
What is the basis of echocardiography?
Measurement of sound waves to generate functional and anatomical information.
What is M-mode used for?
Seeing in 2 dimensions
What does M-mode allow you to see?
If the valves are closing, etc... 2 dimensions.
What can X-ray really show?
Increased heart mass in cardiac failure
Why does heart mass increase in cardiac failure?
Because the body tries to increase stroke volume by increasing preload; but as the heart works harder, the muscle hypertrophies.