Deck 21: Static Lung and Chest Wall Mechanics

Question 1

A patient's lung compliance was measured with the use of an intraesophageal balloon (a measure of pleural pressure).When he has inspired 500 mL,his intraesophageal pressure decreases from -3 cm H₂O at FRC to -7 cm H₂O.What is his lung compliance?

A)1.67 L/cm H₂O
B)0.71 L/cm H₂O
C)0.500 L/cm H₂O
D)0.125 L/cm H₂O

Answer 1

D

Question 2

If the compliance of the lung is 0.2 L/cm H₂O and the compliance of the chest wall is 0.2 L/cm H₂O,what is the compliance across the respiratory system (C_rs)?

A)0.1 L/cm H₂O
B)0.4 L/cm H₂O
C)1.0 L/cm H₂O
D)4.0 L/cm H₂O

Answer 2

A

Question 3

What is the pressure in the alveolus when the translung pressure is 3.5 cm H₂O and the pleural pressure is -8.5 cm H₂O?

A)-5 cm H₂O
B)0 cm H₂O
C)5 cm H₂O
D)-12 cm H₂O

Answer 3

A

Question 4

When the pressure across the respiratory system (P_rs)is 0,which of the following statements is true?

A)The individual is at total lung capacity (TLC).
B)The individual is at FRC.
C)The individual is at residual volume (RV).
D)The transpulmonary (translung)pressure is 0.

Question 5

If pleural pressure changes from -3 cm H₂O to -7 cm H₂O as a subject breathes,and if the functional residual capacity (FRC)increases by 1 L,what is the compliance of the lung?

A)0.1 L/cm H₂O
B)4 cm H₂O/L
C)0.25 L/cm H₂O
D)10 cm H₂O/L

Question 6

An individual with an increase in lung compliance will demonstrate which of the following changes in TLC and the ratio of the total lung capacity to the RV?

A)An increase in TLC and a decrease in RV/TLC
B)A decrease in TLC and a decrease in RV/TLC
C)An increase in TLC and an increase in RV/TLC
D)A decrease in TLC and an increase in RV/TLC
E)No change in TLC or in RV/TLC

Question 7

An individual with respiratory symptoms undergoes pulmonary function testing.The RV measured by helium dilution is increased but is lower than the RV measured by body plethysmography.Which of the following is the most likely explanation for this difference?

A)There is a problem with one of the machines.
B)The individual has severe air trapping.
C)The individual did not keep his mouth pressed tightly around the mouthpiece,and air leaked out during the helium dilution testing.
D)The individual held his breath during body plethysmography.
E)The individual has a loss of lung compliance.

Question 8

Which of the following statements about the effect of surfactant on chest wall compliance is correct?

A)Increased surfactant production is associated with an increase in chest wall compliance.
B)Increased surfactant production is associated with a decrease in chest wall compliance.
C)Decreased surfactant production is associated with an increase in chest wall compliance.
D)Decreased surfactant production is associated with a decrease in chest wall compliance.
E)Surfactant has no effect on chest wall compliance.

Question 9

An individual with pulmonary fibrosis will demonstrate

A)An increase in lung compliance.
B)A decrease in lung compliance.
C)No change in lung compliance.
D)An increase in chest wall compliance.
E)A decrease in chest wall compliance.

Question 10

An individual with increased mucus production and airway inflammation will demonstrate what changes in the residual volume (RV)and FRC?

A)An increase in RV and an increase in FRC
B)An increase in RV and a decrease in FRC
C)A decrease in RV and an increase in FRC
D)A decrease in RV and a decrease in FRC
E)No change in RV or FRC