NUR_302~ARDS: Acute Respiratory Distress
Syndrome Prep with Detailed Rationales
Course Code: NUR_302~ARDS
Course Name: Advanced Medical-Surgical Nursing Care
Topic: Acute Respiratory Distress Syndrome (ARDS) Pathophysiology,
Ventilation Strategies, and Nursing Care
Academic Year: 2026/2027
1. A patient in the intensive care unit is showing signs of respiratory distress 24
hours after an episode of severe gastric aspiration. The nurse notes rapid,
shallow breathing, extreme agitation, and widespread crackles.
Supplemental oxygen via a high-flow non-rebreather mask at 15 L/min is
applied, but the patient's arterial oxygen saturation (SaO₂) remains fixed at
82%. This phenomenon of hypoxemia unresponsive to oxygen
supplementation represents the hallmark of which pulmonary condition?
A. Cardiogenic pulmonary edema secondary to acute myocardial infarction.
B. Acute respiratory distress syndrome (ARDS) characterized by
refractory hypoxemia.
C. Chronic obstructive pulmonary disease (COPD) exacerbation with carbon
dioxide narcosis.
D. Large acute pulmonary embolism causing mechanical tract obstruction.
CORRECT ANSWER: B
RATIONALE: The hallmark clinical indicator of acute respiratory distress
syndrome (ARDS) is refractory hypoxemia, which is defined as hypoxemia
unresponsive to oxygen supplementation regardless of the amount of positive
end-expiratory pressure (PEEP) applied. Aspiration of gastric secretions is a
classic direct lung injury that triggers diffuse epithelial and alveolar damage,
causing massive fluid shifts into the alveoli. This fluid barrier prevents gas
exchange even when 100% inspired oxygen is provided. Distractor A is incorrect
because cardiogenic edema responds more fluidly to oxygen and loop diuretics and
does not show severe intrapulmonary shunting initially. Distractors C and D do not
typically present with this exact pattern of acute, non-responsive diffuse alveolar
infiltration and profound shunting immediately following an aspiration event.
, 2. A nurse is reviewing the arterial blood gas (ABG) results for a mechanically
ventilated patient who was admitted 48 hours ago with severe acute
pancreatitis. The results reveal a pH of 7.21, a PaCO₂ of 55 mmHg, and a
PaO₂ of 48 mmHg while receiving 80% fraction of inspired oxygen (FiO₂).
How should the nurse interpret these findings in the context of the patient's
secondary diagnosis of ARDS?
A. Compensation for chronic metabolic alkalosis from pancreatic enzyme
shifts.
B. Severe respiratory acidosis with critical refractory hypoxemia
matching ARDS criteria.
C. Normal expected ventilator values for a patient undergoing routine
weaning trials.
D. Respiratory alkalosis caused by excessive alveolar hyperventilation.
CORRECT ANSWER: B
RATIONALE: In ARDS, advanced alveolar collapse, narrowing of small
airways, and a marked decrease in lung compliance result in a severe ventilation-
perfusion mismatch and increased alveolar dead space. As a result, the patient
experiences an accumulation of carbon dioxide and a profound drop in
oxygenation, which manifests as respiratory acidosis (pH < 7.35, PaCO₂ > 45
mmHg) combined with extreme hypoxemia (PaO₂ < 50 mmHg). Pancreatitis is a
major indirect lung injury etiology due to systemic circulating enzymes initiating
capillary leaks. Distractors A, C, and D are incorrect because these numbers
represent an acute life-threatening acid-base crisis and structural failure of gas
exchange, not compensation or normal parameters.
3. The intensive care unit team is managing a patient with severe sepsis who
has progressed into full-blown ARDS. The physician orders an increase in
the positive end-expiratory pressure (PEEP) setting on the mechanical
ventilator. What primary physiological mechanism does PEEP perform to
reverse the severe shunting of blood in an ARDS patient's lungs?
A. It selectively lowers the heart rate to allow longer capillary transit time.
B. It provides continuous negative pressure to drain fluid out of the pleural
space.
C. It increases functional residual capacity and reverses alveolar
collapse by keeping alveoli open.
D. It chemically dilates the central bronchial passages to lower airway
resistance.
, CORRECT ANSWER: C
RATIONALE: The primary purpose of PEEP in ARDS ventilation is to
increase the volume of gas remaining in the lungs at the end of expiration
(increasing functional residual capacity). By maintaining pressure above
atmospheric levels at the end of exhalation, PEEP keeps alveoli open and
reverses alveolar collapse, which decreases the shunting of unoxygenated blood
through non-functioning lung segments and significantly improves gas exchange.
This allows the medical team to reduce potentially toxic levels of supplemental
FiO₂. Distractors A, B, and D are incorrect because PEEP works through structural
mechanical pressure on alveoli, not through heart rate alteration, pleural space
suctioning, or chemical bronchodilation.
4. A patient with severe trauma and multiple fractures is placed in the prone
position for 6 hours daily as part of the management strategy for advanced
ARDS. While planning care, what primary therapeutic outcome does the
nurse anticipate from this specific positional modification?
A. An immediate reduction in systemic arterial clotting factors.
B. Improved oxygenation, ventilation, and perfusion across dependent
lung zones.
C. Elimination of the patient's underlying emotional anxiety and agitation.
D. Prevention of any future risk of stress ulcers or gastric distension.
CORRECT ANSWER: B
RATIONALE: Placing an ARDS patient in the prone position recruits
collapsed alveoli in the posterior lung fields and alters structural ventilation-
perfusion dynamics. Prone positioning improves oxygenation, ventilation, and
perfusion by relieving the heart and abdominal contents' weight on dependent lung
tissues and enhancing secretion drainage. Distractor A is incorrect because prone
positioning does not alter systemic coagulation pathways. Distractor C is incorrect
because changing positions does not eliminate the psychological panic caused by
severe dyspnea. Distractor D is incorrect because prone positioning does not
eliminate systemic risk for stress ulcers, which require pharmacological
prophylaxis.
5. A patient with advanced ARDS is fighting the mechanical ventilator,
resulting in high-pressure alarms and a sudden drop in oxygen saturation.
After finding no physical blockages, kinks, or mucus plugs in the
endotracheal tube, the physician orders a continuous infusion of
Syndrome Prep with Detailed Rationales
Course Code: NUR_302~ARDS
Course Name: Advanced Medical-Surgical Nursing Care
Topic: Acute Respiratory Distress Syndrome (ARDS) Pathophysiology,
Ventilation Strategies, and Nursing Care
Academic Year: 2026/2027
1. A patient in the intensive care unit is showing signs of respiratory distress 24
hours after an episode of severe gastric aspiration. The nurse notes rapid,
shallow breathing, extreme agitation, and widespread crackles.
Supplemental oxygen via a high-flow non-rebreather mask at 15 L/min is
applied, but the patient's arterial oxygen saturation (SaO₂) remains fixed at
82%. This phenomenon of hypoxemia unresponsive to oxygen
supplementation represents the hallmark of which pulmonary condition?
A. Cardiogenic pulmonary edema secondary to acute myocardial infarction.
B. Acute respiratory distress syndrome (ARDS) characterized by
refractory hypoxemia.
C. Chronic obstructive pulmonary disease (COPD) exacerbation with carbon
dioxide narcosis.
D. Large acute pulmonary embolism causing mechanical tract obstruction.
CORRECT ANSWER: B
RATIONALE: The hallmark clinical indicator of acute respiratory distress
syndrome (ARDS) is refractory hypoxemia, which is defined as hypoxemia
unresponsive to oxygen supplementation regardless of the amount of positive
end-expiratory pressure (PEEP) applied. Aspiration of gastric secretions is a
classic direct lung injury that triggers diffuse epithelial and alveolar damage,
causing massive fluid shifts into the alveoli. This fluid barrier prevents gas
exchange even when 100% inspired oxygen is provided. Distractor A is incorrect
because cardiogenic edema responds more fluidly to oxygen and loop diuretics and
does not show severe intrapulmonary shunting initially. Distractors C and D do not
typically present with this exact pattern of acute, non-responsive diffuse alveolar
infiltration and profound shunting immediately following an aspiration event.
, 2. A nurse is reviewing the arterial blood gas (ABG) results for a mechanically
ventilated patient who was admitted 48 hours ago with severe acute
pancreatitis. The results reveal a pH of 7.21, a PaCO₂ of 55 mmHg, and a
PaO₂ of 48 mmHg while receiving 80% fraction of inspired oxygen (FiO₂).
How should the nurse interpret these findings in the context of the patient's
secondary diagnosis of ARDS?
A. Compensation for chronic metabolic alkalosis from pancreatic enzyme
shifts.
B. Severe respiratory acidosis with critical refractory hypoxemia
matching ARDS criteria.
C. Normal expected ventilator values for a patient undergoing routine
weaning trials.
D. Respiratory alkalosis caused by excessive alveolar hyperventilation.
CORRECT ANSWER: B
RATIONALE: In ARDS, advanced alveolar collapse, narrowing of small
airways, and a marked decrease in lung compliance result in a severe ventilation-
perfusion mismatch and increased alveolar dead space. As a result, the patient
experiences an accumulation of carbon dioxide and a profound drop in
oxygenation, which manifests as respiratory acidosis (pH < 7.35, PaCO₂ > 45
mmHg) combined with extreme hypoxemia (PaO₂ < 50 mmHg). Pancreatitis is a
major indirect lung injury etiology due to systemic circulating enzymes initiating
capillary leaks. Distractors A, C, and D are incorrect because these numbers
represent an acute life-threatening acid-base crisis and structural failure of gas
exchange, not compensation or normal parameters.
3. The intensive care unit team is managing a patient with severe sepsis who
has progressed into full-blown ARDS. The physician orders an increase in
the positive end-expiratory pressure (PEEP) setting on the mechanical
ventilator. What primary physiological mechanism does PEEP perform to
reverse the severe shunting of blood in an ARDS patient's lungs?
A. It selectively lowers the heart rate to allow longer capillary transit time.
B. It provides continuous negative pressure to drain fluid out of the pleural
space.
C. It increases functional residual capacity and reverses alveolar
collapse by keeping alveoli open.
D. It chemically dilates the central bronchial passages to lower airway
resistance.
, CORRECT ANSWER: C
RATIONALE: The primary purpose of PEEP in ARDS ventilation is to
increase the volume of gas remaining in the lungs at the end of expiration
(increasing functional residual capacity). By maintaining pressure above
atmospheric levels at the end of exhalation, PEEP keeps alveoli open and
reverses alveolar collapse, which decreases the shunting of unoxygenated blood
through non-functioning lung segments and significantly improves gas exchange.
This allows the medical team to reduce potentially toxic levels of supplemental
FiO₂. Distractors A, B, and D are incorrect because PEEP works through structural
mechanical pressure on alveoli, not through heart rate alteration, pleural space
suctioning, or chemical bronchodilation.
4. A patient with severe trauma and multiple fractures is placed in the prone
position for 6 hours daily as part of the management strategy for advanced
ARDS. While planning care, what primary therapeutic outcome does the
nurse anticipate from this specific positional modification?
A. An immediate reduction in systemic arterial clotting factors.
B. Improved oxygenation, ventilation, and perfusion across dependent
lung zones.
C. Elimination of the patient's underlying emotional anxiety and agitation.
D. Prevention of any future risk of stress ulcers or gastric distension.
CORRECT ANSWER: B
RATIONALE: Placing an ARDS patient in the prone position recruits
collapsed alveoli in the posterior lung fields and alters structural ventilation-
perfusion dynamics. Prone positioning improves oxygenation, ventilation, and
perfusion by relieving the heart and abdominal contents' weight on dependent lung
tissues and enhancing secretion drainage. Distractor A is incorrect because prone
positioning does not alter systemic coagulation pathways. Distractor C is incorrect
because changing positions does not eliminate the psychological panic caused by
severe dyspnea. Distractor D is incorrect because prone positioning does not
eliminate systemic risk for stress ulcers, which require pharmacological
prophylaxis.
5. A patient with advanced ARDS is fighting the mechanical ventilator,
resulting in high-pressure alarms and a sudden drop in oxygen saturation.
After finding no physical blockages, kinks, or mucus plugs in the
endotracheal tube, the physician orders a continuous infusion of
