Perfusion

Question 1

diffs that make pulm. circulations different from systemic

Answer 1

1. low pressure and volume
2. low resistance
3. pulsatile
4. constrict with hypoxia

Question 2

difference in resistance versus flow

Answer 2

pulm is 1/10 the resistance, so doesn’t need much pressure to push blood through

Question 3

what is the name for the initial pressure required to open the arteries

Answer 3

critical opening pressure

Question 4

is resistance in lungs linear?

Answer 4

no - changes at different flow rates

Question 5

what changes in pulm. system with to help with increased flow during excercise

Answer 5

no pressure increase – therefore lower resisitance

Question 6

how is resistance reduced?

Answer 6

1. more vessels (parallel cicuit)

2. distension

Question 7

3 forces affecting the pulm blood

Answer 7

1. vessel caliber
2. alveolar vessels
3. extra-alveolar vessels - exposed to pleural pressure

Question 8

how to assess left atrial pressure

Answer 8

Swan Ganz catheter

Question 9

what does Swan Ganz catheter with tip inflated and deflated

Answer 9

1. deflated - PA pressure

2. inflated - LA pressure

Question 10

what happens in RV pressure due to embolism

Answer 10

if new will raise pressure to 45, if had for a while, will go higher due to time for RV hypertrophy

Question 11

what does thermal dilution measure

Answer 11

cardiac output by looking at degree that cold is diffused out

Question 12

formula to measure cardiac output

Answer 12

VO2/(CaO2-CvO2)

Question 13

where in the lungs is bloodflow greatest

Answer 13

bases

Question 14

***3 things that affect blood flow to lungs

Answer 14

1. Pa - driving pressure
2. Pv - back pressure
3. PA - alveolar pressure transmurally

Question 15

pressure ratios in 3 heart zones

Answer 15

1. PA>Pa>PV
2. Pa>PA>PV
3. Pa>PV>PA

Question 16

3 effects of gravity on lung

Answer 16

1. decr Pa above heart and incr. Pa below
2. incr. Pv above heart and dec. PV below
3. lesser effect on alveoli

Question 17

what happens if have hypoxia

Answer 17

low diffusion so body compensates by lowering perfusion

Question 18

what happens in block off R lung

Answer 18

hypoxemia>vasoconstriction>pulmonary hypertension

Question 19

what is pulm. edema

Answer 19

blood vessels leaking fluid into lung

Question 20

causes of pulm edema 2

Answer 20

1. high pressure

2. leaky vessels - permiability or low protein solutes