, Question 1
Which statement best explains why a patient with severe acute respiratory
distress syndrome (ARDS) may exhibit a normal or low PaCO2 despite
profound hypoxemia?
A. Increased dead space ventilation due to microthrombi in the
pulmonary vasculature
B. Compensatory hyperventilation driven by hypoxemic stimulation of
peripheral chemoreceptors
C. Metabolic alkalosis causing compensatory respiratory depression
D. Reduced alveolar compliance leading to decreased minute ventilation
Correct Answer: B - Compensatory hyperventilation driven by
hypoxemic stimulation of peripheral chemoreceptors
RATIONALE
In early ARDS, hypoxemia stimulates peripheral chemoreceptors,
causing hyperventilation and a low or normal PaCO2 (respiratory
alkalosis). Increased dead space and reduced compliance would tend
to raise PaCO2, not lower it. Metabolic alkalosis would cause
compensatory hypoventilation, not hyperventilation.
Question 2
A patient with asthma is prescribed a new inhaler. Which instruction is most
critical to ensure effective drug delivery and reduce local adverse effects?
A. Use a spacer device with a metered-dose inhaler and rinse the mouth
after inhalation
B. Inhale rapidly and deeply immediately after actuating the inhaler
C. Take the medication immediately before meals to enhance absorption
D. Exhale fully into the inhaler before actuation to prime the device
Correct Answer: A - Use a spacer device with a metered-dose
inhaler and rinse the mouth after inhalation
Page 2
, RATIONALE
Using a spacer improves lung deposition and reduces oropharyngeal
candidiasis, especially with inhaled corticosteroids; rinsing the mouth
further minimizes local fungal infections. Rapid inhalation may cause
impaction in the oropharynx, and exhaling into the inhaler can clog
the device. Timing with meals does not affect delivery.
Question 3
Which intervention is most likely to reduce the risk of ventilator-induced lung
injury in a patient with ARDS?
A. Using a tidal volume of 12 mL/kg predicted body weight to maintain
normal PaCO2
B. Applying high levels of positive end-expiratory pressure (PEEP)
without considering plateau pressure
C. Limiting plateau pressure to 30 cm H2O and using tidal volumes of
4-6 mL/kg predicted body weight
D. Maintaining the patient in a supine position to optimize
ventilation-perfusion matching
Correct Answer: C - Limiting plateau pressure to 30 cm H2O and
using tidal volumes of 4-6 mL/kg predicted body weight
RATIONALE
Lung-protective ventilation with low tidal volumes (4-6 mL/kg PBW)
and plateau pressure 30 cm H2O reduces volutrauma and barotrauma
and improves survival in ARDS. High tidal volumes and unchecked
high PEEP increase injury risk. Prone positioning, not supine,
improves outcomes in moderate-severe ARDS.
Question 4
A patient with a history of obstructive sleep apnea (OSA) is being evaluated
for daytime sleepiness. Which pathophysiologic mechanism best explains the
cardiovascular consequences of untreated OSA?
Page 3
, A. Chronic intermittent hypoxia and reoxygenation causing sympathetic
activation and endothelial dysfunction
B. Sustained hypercapnia leading to systemic vasodilation and
hypotension
C. Increased intrathoracic pressure causing enhanced venous return and
preload
D. Chronic respiratory alkalosis resulting in decreased sympathetic
outflow
Correct Answer: A - Chronic intermittent hypoxia and
reoxygenation causing sympathetic activation and endothelial
dysfunction
RATIONALE
Untreated OSA causes repetitive episodes of hypoxia and
reoxygenation, which increase sympathetic activity, oxidative stress,
and endothelial dysfunction, contributing to hypertension and
cardiovascular disease. Hypercapnia and alkalosis are not the primary
mechanisms. Increased intrathoracic pressure actually reduces venous
return.
Question 5
A patient with a suspected pulmonary embolism undergoes CT pulmonary
angiography. Which finding on the CT scan is most specific for pulmonary
embolism?
A. Bilateral pleural effusions
B. Filling defect in the pulmonary artery
C. Ground-glass opacities in the lower lobes
D. Enlarged mediastinal lymph nodes
Correct Answer: B - Filling defect in the pulmonary artery
Page 4
Which statement best explains why a patient with severe acute respiratory
distress syndrome (ARDS) may exhibit a normal or low PaCO2 despite
profound hypoxemia?
A. Increased dead space ventilation due to microthrombi in the
pulmonary vasculature
B. Compensatory hyperventilation driven by hypoxemic stimulation of
peripheral chemoreceptors
C. Metabolic alkalosis causing compensatory respiratory depression
D. Reduced alveolar compliance leading to decreased minute ventilation
Correct Answer: B - Compensatory hyperventilation driven by
hypoxemic stimulation of peripheral chemoreceptors
RATIONALE
In early ARDS, hypoxemia stimulates peripheral chemoreceptors,
causing hyperventilation and a low or normal PaCO2 (respiratory
alkalosis). Increased dead space and reduced compliance would tend
to raise PaCO2, not lower it. Metabolic alkalosis would cause
compensatory hypoventilation, not hyperventilation.
Question 2
A patient with asthma is prescribed a new inhaler. Which instruction is most
critical to ensure effective drug delivery and reduce local adverse effects?
A. Use a spacer device with a metered-dose inhaler and rinse the mouth
after inhalation
B. Inhale rapidly and deeply immediately after actuating the inhaler
C. Take the medication immediately before meals to enhance absorption
D. Exhale fully into the inhaler before actuation to prime the device
Correct Answer: A - Use a spacer device with a metered-dose
inhaler and rinse the mouth after inhalation
Page 2
, RATIONALE
Using a spacer improves lung deposition and reduces oropharyngeal
candidiasis, especially with inhaled corticosteroids; rinsing the mouth
further minimizes local fungal infections. Rapid inhalation may cause
impaction in the oropharynx, and exhaling into the inhaler can clog
the device. Timing with meals does not affect delivery.
Question 3
Which intervention is most likely to reduce the risk of ventilator-induced lung
injury in a patient with ARDS?
A. Using a tidal volume of 12 mL/kg predicted body weight to maintain
normal PaCO2
B. Applying high levels of positive end-expiratory pressure (PEEP)
without considering plateau pressure
C. Limiting plateau pressure to 30 cm H2O and using tidal volumes of
4-6 mL/kg predicted body weight
D. Maintaining the patient in a supine position to optimize
ventilation-perfusion matching
Correct Answer: C - Limiting plateau pressure to 30 cm H2O and
using tidal volumes of 4-6 mL/kg predicted body weight
RATIONALE
Lung-protective ventilation with low tidal volumes (4-6 mL/kg PBW)
and plateau pressure 30 cm H2O reduces volutrauma and barotrauma
and improves survival in ARDS. High tidal volumes and unchecked
high PEEP increase injury risk. Prone positioning, not supine,
improves outcomes in moderate-severe ARDS.
Question 4
A patient with a history of obstructive sleep apnea (OSA) is being evaluated
for daytime sleepiness. Which pathophysiologic mechanism best explains the
cardiovascular consequences of untreated OSA?
Page 3
, A. Chronic intermittent hypoxia and reoxygenation causing sympathetic
activation and endothelial dysfunction
B. Sustained hypercapnia leading to systemic vasodilation and
hypotension
C. Increased intrathoracic pressure causing enhanced venous return and
preload
D. Chronic respiratory alkalosis resulting in decreased sympathetic
outflow
Correct Answer: A - Chronic intermittent hypoxia and
reoxygenation causing sympathetic activation and endothelial
dysfunction
RATIONALE
Untreated OSA causes repetitive episodes of hypoxia and
reoxygenation, which increase sympathetic activity, oxidative stress,
and endothelial dysfunction, contributing to hypertension and
cardiovascular disease. Hypercapnia and alkalosis are not the primary
mechanisms. Increased intrathoracic pressure actually reduces venous
return.
Question 5
A patient with a suspected pulmonary embolism undergoes CT pulmonary
angiography. Which finding on the CT scan is most specific for pulmonary
embolism?
A. Bilateral pleural effusions
B. Filling defect in the pulmonary artery
C. Ground-glass opacities in the lower lobes
D. Enlarged mediastinal lymph nodes
Correct Answer: B - Filling defect in the pulmonary artery
Page 4
