Respiratory System Practice Questions

Question 1

The decrease in O2 affinity of hemoglobin when the pH of blood falls is called:

Accepted Answer

Bohr effect

Answer

Haldane effect

Answer

Centrifugation coefficient

Answer

Oxygen debt

Question 2

In which areas of the lungs can a mismatch of ventilation/perfusion ratio occur?

Accepted Answer

Both apex and base

Answer

Apex only

Answer

Base only

Answer

Neither apex nor base

Question 3

The following flow volume curve indicates:

Accepted Answer

Parenchymal obstructive airway disease

Answer

Restrictive defect

Answer

Extrathoracic obstruction

Answer

Intrathoracic obstruction

Question 4

Which of the following pattern is reflected in the flow-volume curve?

Accepted Answer

Restrictive airway disease

Answer

Obstructive airway disease

Answer

Mixed pattern airway disease

Answer

Central hypoventilation syndrome

Question 5

A 68-year-old man with both severe COPD (emphysema) and newly diagnosed idiopathic pulmonary fibrosis presents with worsening dyspnea. His pressure-volume curve shows a complex pattern with features of both diseases. Static compliance measured at mid-lung volumes is 120 mL/cm H2O. His pulmonologist must decide on optimal management. Synthesizing the pathophysiology of both conditions, what represents the most significant clinical challenge in managing his combined disease?

Accepted Answer

The opposing effects on compliance create a pseudonormal total respiratory compliance masking disease severity

Answer

Emphysema treatment with bronchodilators will worsen fibrosis progression

Answer

Pulmonary rehabilitation cannot address the opposing mechanical derangements

Answer

The increased compliance from emphysema completely negates decreased compliance from fibrosis

Answer

Oxygen therapy beneficial for COPD will accelerate fibrotic changes

Question 6

A 42-year-old woman with systemic sclerosis develops both pulmonary fibrosis and chest wall restriction from skin thickening. Her measured total respiratory system compliance is 30 mL/cm H2O. Testing with complete paralysis and positive pressure ventilation shows isolated lung compliance of 50 mL/cm H2O. She is being considered for immunosuppressive therapy versus supportive care. Evaluate which intervention would provide the greatest improvement in her respiratory mechanics.

Accepted Answer

Combined therapy targeting lung disease with chest wall mobilization

Answer

Aggressive immunosuppression targeting both lung and skin disease

Answer

Lung-directed therapy only, as it contributes more to total compliance reduction

Answer

Supportive care only, as both components contribute equally and irreversibly

Answer

Chest wall-directed physical therapy, as it is the primary limiting factor

Question 7

A 58-year-old man with end-stage pulmonary fibrosis is being evaluated for lung transplantation. His current static compliance is 25 mL/cm H2O (normal: 200 mL/cm H2O). He also has mild obesity (BMI 32) and ankylosing spondylitis affecting chest wall mobility. Post-transplant, assuming successful bilateral lung transplant with normal donor lungs, what would be the expected change in his total respiratory system compliance?

Accepted Answer

Improved but still reduced compliance due to persistent chest wall restriction

Answer

Return to completely normal respiratory compliance matching healthy individuals

Answer

Improved lung compliance but worsened chest wall compliance from surgery

Answer

Worse compliance initially due to transplant rejection and denervation

Answer

No significant change because the primary problem is muscular weakness

Question 8

A research study compares two patients with different lung pathologies but identical functional residual capacity (FRC) of 3.0 L. Patient A has pulmonary fibrosis with FRC above the steep portion of the compliance curve. Patient B has emphysema with FRC on the flat upper portion of the curve. Both attempt to inhale the same tidal volume. Analyzing their work of breathing, which statement best characterizes the difference?

Accepted Answer

Patient B does more elastic work due to hyperinflation beyond optimal compliance

Answer

Patient A does more elastic work; Patient B does more resistive work

Answer

Patient B does less work because emphysematous lungs are more compliant

Answer

Patient A does less work because fibrotic lungs have increased elastic recoil assisting inspiration

Answer

Both do equal work because FRC and tidal volumes are identical

Question 9

A 32-year-old woman develops acute respiratory distress syndrome (ARDS) following sepsis. She is mechanically ventilated with tidal volume 450 mL and plateau pressure 35 cm H2O (PEEP 10 cm H2O). Her static compliance is calculated as 18 mL/cm H2O. The team considers changing ventilator settings. Analyzing her respiratory mechanics, what change would most effectively improve compliance while minimizing ventilator-induced lung injury?

Accepted Answer

Increase PEEP to 15 cm H2O to prevent alveolar collapse

Answer

Increase tidal volume to 600 mL to recruit more alveoli

Answer

Decrease PEEP to 5 cm H2O to reduce plateau pressure

Answer

Switch to pressure-control mode with same plateau pressure

Answer

Increase respiratory rate while maintaining current tidal volume

Question 10

A 55-year-old woman with idiopathic pulmonary fibrosis and a 40-year-old man with severe emphysema both have the same total lung capacity of 4.5 L on pulmonary function testing. However, their pressure-volume curves show opposite patterns. During inspiration from FRC, which patient requires greater change in pleural pressure to achieve the same tidal volume, and why?

Accepted Answer

The fibrosis patient, because decreased compliance requires greater pressure change for the same volume

Answer

The emphysema patient, because decreased elastic recoil requires more negative pressure to inflate

Answer

The fibrosis patient, because increased surface tension prevents alveolar expansion

Answer

The emphysema patient, because increased airway resistance requires more driving pressure

Answer

Both require the same pressure because they have equal total lung capacity

Respiratory System

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