W7-V/Q relationship

Question 1

compare the apex to the base in terms of intrapleural pressure, transmural pressure, intravascular pressure and alveoli and V/Q

Answer 1

intrapleural pressure- more negative

transmural pressure- greater

intravascular pressure- lower

alveoli - large

V/Q- higher

less blood flow, ventillation and perfusion

Question 2

compare the Va/Q ratio at the base to apex

Answer 2

larger at apex

1 at the level of the heart

less than 1 at level of diaphram

Question 3

what is the normal alveolar-arterialO2 difference

Answer 3

5-19

more than 20 is pathologic

Question 4

describe the differences in V/Q with Chronic Pulmonary Emphysema

•Alveolar wall damage leads to wasted ventilation, leads to decreased VA/ Q in some parts

•

•Obstruction leads to physiologic shunt and an increase in VA/ Q in other parts of same lung

Answer 4

increases overall

• Alveolar wall damage leads to wasted ventilation, leads to decreased VA/ Q in some parts
• Obstruction leads to physiologic shunt and an increase in VA/ Q in other parts of same lung

Question 5

what things can cause obstructed airway

Answer 5

mucus, edema, narrowed airway

Question 6

A 56-year-old man is found to have a pulmonary embolus causing blood flow to be absent in lower lung alveoli and VA/Q equal to infinity in those areas of his lung. Which of the following best describe PAo2and PAco2in these areas of his lungs?

Answer 6

PAo2=149 mmHg, PAco2 = 0 mmHg

Question 7

Define the possible inequalities in Va/Q

deadspace ventilation

high ventillation

normal ventilation

poor ventilation

intrapulmonary shunt

Answer 7

Question 8

: A 56-year-old man with emphysema is found to have air trapping in lower lung alveoli and VA/Q equal to 0 in some areas of his lungs. Which of the following best describe PAo2and PAco2in these areas of his lungs

Answer 8

PAo2=40 mmHg, PAco2 = 45 mmHg

Question 9

what does emphysemia or pneumonia do to the V/Q ratio compared to a pulmonary embolus

Answer 9

emphysemia and pneumonia-

reduced surface area for gas exchange so the O2 is low but the CO2 is normal

PE-

increased V/Q

Question 10

Differentiate type A and B emphysemia in terms of their V/Q graphs

Answer 10

first is type a second is type B

A- normal PO2 but Ve is high

B- dysnpea

Question 11

what is the Maximum expiratory flow is dependent on how does it change at high and low volumes

Answer 11

the amount of airway collapse

high- decreases

low- increases

due to release of mechanical tethering of bronchioles

Question 12

what are examples of obstructive and restrictive diseases of the lung

how do these impact the FEV/FVC ratio

Answer 12

obstructive (asthma, emphysema)

restrictive TB, silicosis, kyphosis

If the FEV and te FVC is abnormal

If the %predicted for FEV1/FVC is 88%-90% or higher, then the patient has a restricted lung disease. If the %predicted for FEV1/FVC is 69% or lower, then the patient has an obstructed lung disease.