NBRC TMC Oxygen Therapy and Airway Management Exam
Questions and Verified Answers with Rationale | Latest
Edition 2026/2027
Question 1
An adult patient with chronic obstructive pulmonary disease and acute-
on-chronic hypoxemic respiratory failure is admitted to the emergency
department. Arterial blood gas results on room air show pH 7.34, PaCO2
58 mm Hg, PaO2 50 mm Hg, and HCO3 31 mEq/L. Which of the
following oxygen delivery devices is most appropriate to initiate
controlled, precise oxygen therapy?
A. Simple oxygen mask at 10 L/min
B. Nasal cannula at 6 L/min
C. Venturi mask delivering a controlled FiO2 of 0.24 to 0.28
D. Non-rebreathing mask at 15 L/min
Correct Answer: C
Rationale: Patients with chronic hypercapnia and chronic obstructive
pulmonary disease are at risk of acute respiratory depression if given
unmonitored high concentrations of oxygen, which can relieve hypoxic
drive and worsen ventilation-perfusion mismatch. A Venturi mask
provides a fixed, controlled fraction of inspired oxygen, allowing precise
titration to target an SpO2 of 88 to 92 percent without inducing severe
hypercapnia.
Question 2
A patient is receiving oxygen via a non-rebreathing mask at 12 L/min.
During inspiration, the respiratory therapist observes that the reservoir
,bag collapses completely. Which of the following is the most
appropriate corrective action?
A. Remove the one-way valve from the exhalation port.
B. Increase the oxygen flow rate until the reservoir bag remains
slightly inflated at end-inspiration.
C. Switch the patient to a simple face mask at 5 L/min.
D. Decrease the flow rate to prevent bag rupture.
Correct Answer: B
Rationale: Complete collapse of the reservoir bag on a non-rebreathing
mask during inspiration indicates that the patient's inspiratory flow
demand exceeds the incoming oxygen flow rate, which can lead to
rebreathing of carbon dioxide or insufficient oxygen delivery. Increasing
the flow rate ensures the bag stays partially inflated during inspiration.
Question 3
When calculating the duration of cylinder flow for an E-cylinder of
medical oxygen with a pressure reading of 1,500 psig operating at a
continuous flow rate of 3 L/min, which of the following values is
correct? (Note: E-cylinder conversion factor is 0.28 L/psi).
A. 70 minutes
B. 140 minutes
C. 210 minutes
D. 280 minutes
Correct Answer: B
,Rationale: The formula for calculating cylinder duration is (Pressure in
psig \times Cylinder Factor) / Flow Rate. For an E-cylinder, the factor is
0.28. Therefore: (1,500 \times 0.28) / 3 = = 140 minutes.
Question 4
A patient is intubated with a cuffed oral endotracheal tube. To minimize
the risk of tracheal mucosal ischemia and necrosis, what is the
recommended maximum limit for endotracheal tube cuff pressure?
A. 10 to 15 mm Hg
B. 20 to 25 cm H2O (or approximately 15 to 20 mm Hg)
C. 40 to 50 cm H2O
D. 60 mm Hg
Correct Answer: B
Rationale: Tracheal capillary perfusion pressure ranges between 20 and
30 mm Hg (approximately 25 to 35 cm H2O). Maintaining endotracheal
tube cuff pressures below 20 to 25 cm H2O prevents capillary occlusion,
mucosal ischemia, necrosis, and subsequent tracheal stenosis while
preventing air leaks.
Question 5
During an emergency intubation attempt, the respiratory therapist inserts
an endotracheal tube and confirms placement using auscultation and an
exhaled carbon dioxide colorimetric detector. The detector paper
changes from purple to yellow. What is the clinical interpretation of this
color change?
A. The endotracheal tube is correctly positioned in the trachea.
B. The endotracheal tube is accidentally placed in the esophagus.
, C. The patient has severe metabolic alkalosis.
D. There is complete circulatory arrest.
Correct Answer: A
Rationale: Colorimetric end-tidal carbon dioxide detectors utilize litmus-
like paper that changes color in the presence of carbon dioxide. A
change from purple (or blue) to yellow indicates the presence of exhaled
carbon dioxide, confirming correct tracheal placement. A lack of color
change (remaining purple) strongly suggests esophageal intubation.
Question 6
An adult male patient requires nasal intubation. Which of the following
blades is commonly preferred for a nasotracheal intubation approach
because it provides better visualization and creates a direct line of sight?
A. Miller curved blade size 3
B. Macintosh curved blade size 3 or 4
C. Wisconsin straight blade size 2
D. Flanged Miller blade size 1
Correct Answer: B
Rationale: Macintosh curved blades are inserted into the vallecula,
lifting the epiglottis indirectly and opening a wide field of view, which is
advantageous for both oral and nasal intubation procedures compared to
straight blades.
Question 7
A patient with a tracheostomy tube develops sudden respiratory distress
and complete inability to pass a suction catheter through the tube. The
Questions and Verified Answers with Rationale | Latest
Edition 2026/2027
Question 1
An adult patient with chronic obstructive pulmonary disease and acute-
on-chronic hypoxemic respiratory failure is admitted to the emergency
department. Arterial blood gas results on room air show pH 7.34, PaCO2
58 mm Hg, PaO2 50 mm Hg, and HCO3 31 mEq/L. Which of the
following oxygen delivery devices is most appropriate to initiate
controlled, precise oxygen therapy?
A. Simple oxygen mask at 10 L/min
B. Nasal cannula at 6 L/min
C. Venturi mask delivering a controlled FiO2 of 0.24 to 0.28
D. Non-rebreathing mask at 15 L/min
Correct Answer: C
Rationale: Patients with chronic hypercapnia and chronic obstructive
pulmonary disease are at risk of acute respiratory depression if given
unmonitored high concentrations of oxygen, which can relieve hypoxic
drive and worsen ventilation-perfusion mismatch. A Venturi mask
provides a fixed, controlled fraction of inspired oxygen, allowing precise
titration to target an SpO2 of 88 to 92 percent without inducing severe
hypercapnia.
Question 2
A patient is receiving oxygen via a non-rebreathing mask at 12 L/min.
During inspiration, the respiratory therapist observes that the reservoir
,bag collapses completely. Which of the following is the most
appropriate corrective action?
A. Remove the one-way valve from the exhalation port.
B. Increase the oxygen flow rate until the reservoir bag remains
slightly inflated at end-inspiration.
C. Switch the patient to a simple face mask at 5 L/min.
D. Decrease the flow rate to prevent bag rupture.
Correct Answer: B
Rationale: Complete collapse of the reservoir bag on a non-rebreathing
mask during inspiration indicates that the patient's inspiratory flow
demand exceeds the incoming oxygen flow rate, which can lead to
rebreathing of carbon dioxide or insufficient oxygen delivery. Increasing
the flow rate ensures the bag stays partially inflated during inspiration.
Question 3
When calculating the duration of cylinder flow for an E-cylinder of
medical oxygen with a pressure reading of 1,500 psig operating at a
continuous flow rate of 3 L/min, which of the following values is
correct? (Note: E-cylinder conversion factor is 0.28 L/psi).
A. 70 minutes
B. 140 minutes
C. 210 minutes
D. 280 minutes
Correct Answer: B
,Rationale: The formula for calculating cylinder duration is (Pressure in
psig \times Cylinder Factor) / Flow Rate. For an E-cylinder, the factor is
0.28. Therefore: (1,500 \times 0.28) / 3 = = 140 minutes.
Question 4
A patient is intubated with a cuffed oral endotracheal tube. To minimize
the risk of tracheal mucosal ischemia and necrosis, what is the
recommended maximum limit for endotracheal tube cuff pressure?
A. 10 to 15 mm Hg
B. 20 to 25 cm H2O (or approximately 15 to 20 mm Hg)
C. 40 to 50 cm H2O
D. 60 mm Hg
Correct Answer: B
Rationale: Tracheal capillary perfusion pressure ranges between 20 and
30 mm Hg (approximately 25 to 35 cm H2O). Maintaining endotracheal
tube cuff pressures below 20 to 25 cm H2O prevents capillary occlusion,
mucosal ischemia, necrosis, and subsequent tracheal stenosis while
preventing air leaks.
Question 5
During an emergency intubation attempt, the respiratory therapist inserts
an endotracheal tube and confirms placement using auscultation and an
exhaled carbon dioxide colorimetric detector. The detector paper
changes from purple to yellow. What is the clinical interpretation of this
color change?
A. The endotracheal tube is correctly positioned in the trachea.
B. The endotracheal tube is accidentally placed in the esophagus.
, C. The patient has severe metabolic alkalosis.
D. There is complete circulatory arrest.
Correct Answer: A
Rationale: Colorimetric end-tidal carbon dioxide detectors utilize litmus-
like paper that changes color in the presence of carbon dioxide. A
change from purple (or blue) to yellow indicates the presence of exhaled
carbon dioxide, confirming correct tracheal placement. A lack of color
change (remaining purple) strongly suggests esophageal intubation.
Question 6
An adult male patient requires nasal intubation. Which of the following
blades is commonly preferred for a nasotracheal intubation approach
because it provides better visualization and creates a direct line of sight?
A. Miller curved blade size 3
B. Macintosh curved blade size 3 or 4
C. Wisconsin straight blade size 2
D. Flanged Miller blade size 1
Correct Answer: B
Rationale: Macintosh curved blades are inserted into the vallecula,
lifting the epiglottis indirectly and opening a wide field of view, which is
advantageous for both oral and nasal intubation procedures compared to
straight blades.
Question 7
A patient with a tracheostomy tube develops sudden respiratory distress
and complete inability to pass a suction catheter through the tube. The
