Intro to CVP

Question 1

Oxygen Delivery equation

Answer 1

arterial O2 x cardiac output

Question 2

oxygen consumption equation

Answer 2

(arterial O2 - venous O2) x cardiac output

Question 3

oxygen extraction ratio

Answer 3

consumption/delivery

VO2/DO2

Question 4

DO2 vs. actual demand at rest

Answer 4

DO2 3-4x greater than actual demand

Question 5

step 1 of oxygen transport

Answer 5

inspired oxygen and quality of air

Question 6

step 2 of oxygen transport

Answer 6

airways

Question 7

step 3 of oxygen transport

Answer 7

lungs and chest wall

Question 8

which muscles allow for expansion of lungs

Answer 8

diaphragm and external intercostals

Question 9

where is capillary pressure lowest in the lung?

-why?

Answer 9

in the top of the lung

-due to gravity drawing blood to the bottom of the lung

Question 10

what muscles assist in forced expiration

Answer 10

interal intercostals

abdominals

Question 11

step 4 of oxygen transport

Answer 11

diffusion

Question 12

what is diffusion?

-based on what factors?

Answer 12

transfer of oxygen from alveolar sacs to pulmonary circulation
based on
-surface area of alveolar capillary membrane
-diffusing capacity of alveolar capillary membrane
-pulmonary capillary blood volume
-ventilation/perfusion ratio
-transit time of blood in alveolar capillary membrane

Question 13

amount of oxygen that diffuses across alveolar-capillary membrane varies

• directly with…
• inversely with…

Answer 13

directly with size (surface area)

inversely with thickness

Question 14

what change in the alveoli occurs in individuals with emphysema?

Answer 14

decreased surface area

Question 15

step 5 of oxygen transport

Answer 15

perfusion

Question 16

what is the V/Q ratio?

-typical value

Answer 16

amount of air getting to the alveoli/amount of blood going to the lungs
V/Q = 0.8

Question 17

is perfusion high or low in the apical part of the lung?

Answer 17

low (due to gravity)

Question 18

how is ventilation to the apical part of the lung?

Answer 18

good (alveoli expand fully)

Question 19

step 6 of oxygen transport

Answer 19

myocardial function

Question 20

myocardial function is dependent on…

Answer 20

electrical excitation
cardiac output
-preload
-force (inotropic effect) an drate of contraction (chronotropic effect)
-afterload
--resistance to blood ejecting from the heart
measures of impairment
-heart rate
-ejection fraction

Question 21

step 7 of oxygen transport

Answer 21

peripheral circulation

Question 22

step 8 of oxygen transport

Answer 22

tissue extraction and utilization of oxygen

Question 23

OER

• stands for
• what is it
• value at rest

Answer 23

oxygen extraction ratio
amount of O2 extracted at rest
23%

Question 24

rate of O2 extraction regulated by…

Answer 24

oxygen demand (not availability)

Question 25

step 9 of oxygen transport

Answer 25

return of partially saturated blood and CO2 to lungs

Question 26

which step of oxygen transport would be affected in

• myocardial infarction
• pneumothorax
• asthma
• pulmonary embolus
• hypertension
• anemia

Answer 26

MCI
-6 MC function
pneumothorax
-3 lung and chest wall
asthma
-2 airways, 4 diffusion
pulmonary embolus
-5 perfusion
hypertension
-7 peripheral circulation
anemia
-8 tissue extraction and utilization of O2

Question 27

factors that change O2 transport

Answer 27

normal
-activity, position, emotional stress
disease

Question 28

greatest influence on O2 transport

Answer 28

gravity

-small shifts in gravity –> big fluid shifts

Question 29

effects of restricted activity

Answer 29

decreases VO2 and CO with exercise

decreases OER