NURS 121L-A | Medical-Surgical Nursing Practicum | Oxygen Therapy
& Respiratory Care | 2026 Update WCU
1. A patient with chronic obstructive pulmonary disease (COPD) is receiving
oxygen via a nasal cannula at 2 L/min. The nurse notes the patient’s respiratory
rate has decreased from 18 to 10 breaths/min and the patient is becoming
lethargic. Which physiological phenomenon is likely occurring?
A. Oxygen toxicity affecting the central nervous system
B. Absorption atelectasis due to high nitrogen washout
C. Suppression of the hypoxic drive for ventilation
D. Absorption of carbon dioxide in the alveoli
Answer: C
Rationale: In some patients with chronic hypercapnia (like COPD), the respiratory center
becomes less sensitive to CO2, and hypoxemia becomes the primary stimulus for breathing.
Providing supplemental oxygen can abolish this ‘hypoxic drive,’ leading to hypoventilation
and CO2 retention.
2. When interpreting arterial blood gas (ABG) results, the nurse finds: pH 7.28,
PaCO2 55 mmHg, and HCO3 28 mEq/L. How should the nurse categorize this
acid-base imbalance?
A. Partially compensated metabolic acidosis
B. Fully compensated metabolic alkalosis
C. Uncompensated respiratory acidosis
D. Partially compensated respiratory acidosis
Answer: D
Rationale: The pH is low (acidosis), the PaCO2 is high (respiratory cause), and the HCO3 is
high (compensatory mechanism by the kidneys). Since the pH is not yet within the normal
range, it is partially compensated.
,3. A nurse is caring for a patient requiring a precise concentration of oxygen at
35% FiO2. Which oxygen delivery device is most appropriate for this
requirement?
A. Simple face mask
B. Venturi mask
C. Nasal cannula
D. Non-rebreather mask
Answer: B
Rationale: The Venturi mask is the most accurate device for delivering a specific, fixed
concentration of oxygen by using different sized adapters or a dial to mix room air with
oxygen flow.
4. The nurse is assessing a patient with a chest tube connected to a water-seal
drainage system. Constant, vigorous bubbling is observed in the water-seal
chamber. What does this finding indicate?
A. There is a large air leak in the drainage system or the patient’s pleural space
B. The system is functioning normally and removing air from the pleural space
C. The suction pressure is set too high on the wall regulator
D. The patient has developed a tension pneumothorax
Answer: A
Rationale: Intermittent bubbling is expected in a patient with a pneumothorax, but
constant, vigorous bubbling in the water-seal chamber typically indicates a persistent air
leak in the system or the pleural cavity.
, 5. What is the primary rationale for maintaining the water level in the suction
control chamber of a wet-suction chest tube drainage system?
A. To prevent atmospheric air from entering the pleural space
B. To provide a visual indicator of the patient’s intrapleural pressure
C. To filter bacteria from the air being exhausted from the lungs
D. To regulate the amount of suction applied to the pleural cavity
Answer: D
Rationale: In a wet-suction system, the depth of the water in the suction control chamber
determines the amount of suction applied, regardless of the wall suction setting.
6. A patient is being treated for Acute Respiratory Distress Syndrome (ARDS).
The ventilator is set to deliver Positive End-Expiratory Pressure (PEEP). What is
the primary goal of PEEP?
A. To decrease the work of breathing by assisting inspiration
B. To clear secretions from the distal bronchioles
C. To prevent alveolar collapse and increase functional residual capacity
D. To increase the tidal volume delivered with each breath
Answer: C
Rationale: PEEP maintains pressure in the airways at the end of exhalation, which keeps
alveoli open (prevents atelectasis), improves gas exchange, and allows for lower FiO2
settings.
7. Which of the following is considered an early clinical sign of hypoxia?
A. Cyanosis of the mucous membranes
B. Restlessness and agitation
C. Bradycardia
D. Bradypnea
Answer: B
& Respiratory Care | 2026 Update WCU
1. A patient with chronic obstructive pulmonary disease (COPD) is receiving
oxygen via a nasal cannula at 2 L/min. The nurse notes the patient’s respiratory
rate has decreased from 18 to 10 breaths/min and the patient is becoming
lethargic. Which physiological phenomenon is likely occurring?
A. Oxygen toxicity affecting the central nervous system
B. Absorption atelectasis due to high nitrogen washout
C. Suppression of the hypoxic drive for ventilation
D. Absorption of carbon dioxide in the alveoli
Answer: C
Rationale: In some patients with chronic hypercapnia (like COPD), the respiratory center
becomes less sensitive to CO2, and hypoxemia becomes the primary stimulus for breathing.
Providing supplemental oxygen can abolish this ‘hypoxic drive,’ leading to hypoventilation
and CO2 retention.
2. When interpreting arterial blood gas (ABG) results, the nurse finds: pH 7.28,
PaCO2 55 mmHg, and HCO3 28 mEq/L. How should the nurse categorize this
acid-base imbalance?
A. Partially compensated metabolic acidosis
B. Fully compensated metabolic alkalosis
C. Uncompensated respiratory acidosis
D. Partially compensated respiratory acidosis
Answer: D
Rationale: The pH is low (acidosis), the PaCO2 is high (respiratory cause), and the HCO3 is
high (compensatory mechanism by the kidneys). Since the pH is not yet within the normal
range, it is partially compensated.
,3. A nurse is caring for a patient requiring a precise concentration of oxygen at
35% FiO2. Which oxygen delivery device is most appropriate for this
requirement?
A. Simple face mask
B. Venturi mask
C. Nasal cannula
D. Non-rebreather mask
Answer: B
Rationale: The Venturi mask is the most accurate device for delivering a specific, fixed
concentration of oxygen by using different sized adapters or a dial to mix room air with
oxygen flow.
4. The nurse is assessing a patient with a chest tube connected to a water-seal
drainage system. Constant, vigorous bubbling is observed in the water-seal
chamber. What does this finding indicate?
A. There is a large air leak in the drainage system or the patient’s pleural space
B. The system is functioning normally and removing air from the pleural space
C. The suction pressure is set too high on the wall regulator
D. The patient has developed a tension pneumothorax
Answer: A
Rationale: Intermittent bubbling is expected in a patient with a pneumothorax, but
constant, vigorous bubbling in the water-seal chamber typically indicates a persistent air
leak in the system or the pleural cavity.
, 5. What is the primary rationale for maintaining the water level in the suction
control chamber of a wet-suction chest tube drainage system?
A. To prevent atmospheric air from entering the pleural space
B. To provide a visual indicator of the patient’s intrapleural pressure
C. To filter bacteria from the air being exhausted from the lungs
D. To regulate the amount of suction applied to the pleural cavity
Answer: D
Rationale: In a wet-suction system, the depth of the water in the suction control chamber
determines the amount of suction applied, regardless of the wall suction setting.
6. A patient is being treated for Acute Respiratory Distress Syndrome (ARDS).
The ventilator is set to deliver Positive End-Expiratory Pressure (PEEP). What is
the primary goal of PEEP?
A. To decrease the work of breathing by assisting inspiration
B. To clear secretions from the distal bronchioles
C. To prevent alveolar collapse and increase functional residual capacity
D. To increase the tidal volume delivered with each breath
Answer: C
Rationale: PEEP maintains pressure in the airways at the end of exhalation, which keeps
alveoli open (prevents atelectasis), improves gas exchange, and allows for lower FiO2
settings.
7. Which of the following is considered an early clinical sign of hypoxia?
A. Cyanosis of the mucous membranes
B. Restlessness and agitation
C. Bradycardia
D. Bradypnea
Answer: B
