Quiz 4

Question 1

1. How is the velocity of blood flow related to the cross-sectional area of a blood vessel or group of blood vessels?

Answer 1

Velocity is inversely related to cross-sectional area

V=Q(flow)/A(cross-sectional area)

Question 2

2. Name a return-to-flow technique of blood pressure measurement.

Answer 2

• Palpation
• Pulse ox (plethysmographic waveform)
• arterial catheter

Question 3

4. In a healthy individual with disease-free arteries, does systolic blood pressure increase or decrease in the leg relative to the proximal aorta?

Answer 3

Increases

Question 4

7. What are the 3 waves seen in a normal CVP tracing?

Answer 4

• a - right atrial contraction (correlates with p wave)
• c - tricuspid valve/ventricular contraction (end of QRS)
• v - blood filling R atrium (end of T wave)

Question 5

8. What are the different waveforms that would be encountered when inserting a Swan-Ganz catheter from its insertion in the right jugular vein to its final position in a pulmonary artery?

Answer 5

• RV pressure
• PA Pressure
• Wedge pressure

Question 6

9. What information can be gathered from a Swan-Ganz catheter? DIRECTLY

Answer 6

• CVP
• RA/RV pressures
• PA pressures
• PAOP/Wedge
• CO
• SvO2

Question 7

11. What are the 2 steps of “zeroing” a transducer?

Answer 7

-Zero
-Appropriate height relative to patient position
(5 cm below the left sternal border at the fourth intercostal space)

Question 8

12. What is the Fick Principle method of measuring cardiac output?

Answer 8

o2 per minute absorbed by lungs/arteriovenous o2 difference

Question 9

5. What is cerebral perfusion pressure?

Answer 9

The difference between arterial and venous pressures

MAP – CVP or ICP (whichever is higher)

Question 10

6. What is Poiseuille’s Law? and what components (3)

Answer 10

Determines resistance to flow

(Radius, Length, Viscosity

Question 11

7. According to Poiseuille’s Law what factor has the greatest impact on the rate of blood flow through a vessel?

Answer 11

Radius

Question 12

8. What is resistance?

Answer 12

Resistance is the impediment to blood flow in a vessel

Question 13

9. Can resistance be measured directly?

Answer 13

no

Question 14

10. What is the formula for calculating Systemic Vascular Resistance?

Answer 14

(MAP - CVP)/CO x 80

Question 15

11. What is the formula for calculating Pulmonary Vascular Resistance?

Answer 15

(MPAP - PCWP)/CO x 80

Question 16

12. How would you calculate resistance when blood vessels are arranged in series?

Answer 16

add up the resistances to get total

R1 + R2 = Rtotal

Question 17

13. How would you calculate resistance when blood vessels are arranged in parallel?

Answer 17

1/R1 + 1/R2 = 1/Rtotal

note: the total resistance is less than any single blood vessel also means better flow total than single vessel

Question 18

14. If you added another blood vessel in a parallel arrangement, would total vascular resistance increase or decrease? Why?

Answer 18

Decrease

Question 19

15. What is laminar flow?

Answer 19

Smooth flow

Question 20

16. What is turbulent flow?

Answer 20

the blood flows crosswise in the vessel and along the vessel, usually forming whorls in the blood, callededdy currents

Question 21

17. What formula could you use to predict laminar versus turbulent flow?

Answer 21

Reynold number

Density, Diameter, Viscosity, Velocity

Question 22

18. What is the relationship of hematocrit to blood viscosity?

Answer 22

More hematocrit, more viscosity

Question 23

19. As blood pressure increases within a vessel why does blood flow increase much greater than one would expect? what law? Ohms

Answer 23

because (P.arterial - P.venous)/Radius = flow

Ohms law

Question 24

1. What is the most important monitor in the operating room?

Answer 24

The anesthetist

Question 25

5. What is damping in an arterial line tracing?

Answer 25

How quickly vibrations come to rest

Question 26

6. What is ringing in an arterial line tracing? What range?

Answer 26

When the fast flush abruptly ends, the transducer system oscillates at its natural frequency. This can be measured and assessed for adequacy. >24 hz

Question 27

2. According to Ohm's Law what 2 factors determine blood flow through a blood vessel?

Answer 27

Pressure or voltage drop, resistance

Question 28

3. Define blood pressure.

Answer 28

Blood pressure is the force exerted by the blood against any unit area of the vessel wall

Question 29

4. What is the conversion factor from mm-Hg (mercury) to cm-H2O?

Answer 29

1 mmHg = 1.36 cm H2O

Question 30

excessive damping leads to

Answer 30

underestimated systolic and overestimated diastolic

Question 31

Underdamping leads to

Answer 31

overestimated systolic and underestimated diastolic