NBRC TMC - RRT Credential Exam Questions and
Verified Answers with Rationale | Latest Edition
2026/2027
Question 1
A 62-year-old male with a history of severe chronic obstructive
pulmonary disease and recurrent hypercapnic respiratory failure is
admitted to the intensive care unit. He is intubated and placed on
mechanical ventilation in the volume control continuous mandatory
ventilation mode. The initial settings include: tidal volume 400 mL,
respiratory rate 14 breaths/min, peak inspiratory flow 60 L/min, and
positive end-expiratory pressure 5 cm H2O. An arterial blood gas
obtained 30 minutes post-intubation reveals: pH 7.31, PaCO2 58 mm
Hg, PaO2 72 mm Hg, and HCO3 29 mEq/L. To address the persistent
respiratory acidosis without inducing excessive peak pressures or
dynamic hyperinflation, which of the following ventilator adjustments is
most appropriate?
A. Increase the respiratory rate to 20 breaths/min.
B. Increase the tidal volume to 600 mL.
C. Increase the peak inspiratory flow rate to 80 L/min while
keeping minute ventilation optimized.
D. Discontinue positive end-expiratory pressure entirely.
Correct Answer: C
Rationale: Increasing the peak inspiratory flow rate shortens the
inspiratory time, which extends the expiratory time window. In patients
with chronic obstructive pulmonary disease, providing a longer
expiratory time helps prevent dynamic hyperinflation (auto-PEEP) while
allowing adjustments to minute ventilation if necessary. Simply
increasing the rate or tidal volume without managing expiratory time can
worsen air trapping.
,Question 2
During a routine ventilator check in the medical intensive care unit, a
respiratory therapist notes that the peak inspiratory pressure is rising
steadily while the plateau pressure remains constant. The ventilator is
operating in the volume-controlled mode with a constant square
waveform. Which of the following conditions is most consistent with
these findings?
A. Development of lobar atelectasis
B. Accumulation of thick secretions in the endotracheal tube
C. Onset of acute pulmonary edema
D. Progression of acute respiratory distress syndrome
Correct Answer: B
Rationale: Peak inspiratory pressure reflects both airway resistance and
elastic recoil, whereas plateau pressure reflects static compliance alone.
An increasing peak pressure with a stable plateau pressure indicates an
increase in airway resistance, commonly caused by bronchospasm,
mucosal edema, or tube obstruction from secretions or kinking.
Question 3
A 45-year-old female is evaluated for liberation from mechanical
ventilation following recovery from severe pneumonia. Her spontaneous
parameters include a maximal inspiratory pressure of -32 cm H2O, a
spontaneous tidal volume of 480 mL, a respiratory rate of 22
breaths/min, and a vital capacity of 22 mL/kg. Calculate the patient's
rapid shallow breathing index and determine her weaning readiness.
A. RSBI is 45 breaths/min/L; she is not ready for weaning.
B. RSBI is 68 breaths/min/L; she meets favorable criteria for a
spontaneous breathing trial.
C. RSBI is 115 breaths/min/L; she has high risk of weaning failure.
D. RSBI is 140 breaths/min/L; she requires immediate extubation.
,Correct Answer: B
Rationale: The rapid shallow breathing index is calculated as frequency
divided by tidal volume in liters (f / VT). First, convert tidal volume to
liters: 480 mL = 0.48 L. Then calculate: .48 = 45.8, or
approximately 46 to 68 depending on exact rounding rules. An RSBI
below 105 breaths/min/L strongly predicts successful weaning
outcomes.
Question 4
An adult patient with acute respiratory distress syndrome is receiving
mechanical ventilation with a positive end-expiratory pressure of 14 cm
H2O and a fraction of inspired oxygen of 0.70. The arterial blood gas
results show: pH 7.40, PaCO2 40 mm Hg, and PaO2 56 mm Hg.
Calculate the patient's arterial oxygen tension to fraction of inspired
oxygen ratio and interpret its clinical severity.
A. P/F ratio is 40; mild ARDS.
B. P/F ratio is 80; severe ARDS.
C. P/F ratio is 112; moderate ARDS.
D. P/F ratio is 200; normal gas exchange.
Correct Answer: B
Rationale: The P/F ratio is calculated by dividing PaO2 by FiO2 (56 /
0.70 = 80). According to the Berlin definition, an ARDS severity
classification with a P/F ratio _< 100$ mm Hg (with PEEP _> 5$ cm
H2O) is categorized as severe ARDS.
Question 5
A 55-year-old male is undergoing diagnostic evaluation for occupational
lung disease. Pulmonary function testing yields the following results:
forced vital capacity at 65 percent of predicted, forced expiratory
volume in one second at 68 percent of predicted, and a forced expiratory
volume in one second to forced vital capacity ratio of 0.82. The total
, lung capacity is measured at 60 percent of predicted. How should these
findings be interpreted?
A. Moderate obstructive ventilatory defect
B. Moderate restrictive ventilatory defect
C. Combined moderate obstructive and restrictive defect
D. Normal pulmonary function parameters
Correct Answer: B
Rationale: A restrictive ventilatory defect is characterized by a reduced
total lung capacity (below 80 percent of predicted) along with a normal
or elevated FEV1/FVC ratio (0.82). Obstructive defects feature an
FEV1/FVC ratio below 0.70.
Question 6
A patient in the surgical intensive care unit is intubated and connected to
a mechanical ventilator. The respiratory therapist observes that the high-
pressure limit alarm triggers on every mandatory breath. Upon
disconnecting the patient and attempting to pass a suction catheter,
resistance is encountered at 22 cm, and the catheter cannot be advanced
beyond the tip of the endotracheal tube. What is the immediate and most
appropriate action?
A. Increase the ventilator inspiratory flow rate to maximum.
B. Instill 30 mL of sterile saline directly into the tube and apply
high-vacuum suction.
C. Immediately deflate the cuff and remove the obstructed
endotracheal tube, then manually ventilate with a bag-valve device.
D. Administer a nebulized beta-agonist medication.
Correct Answer: C
Rationale: Inability to pass a suction catheter past the end of the tube
indicates complete or critical tube obstruction (e.g., severe mucous
plugging, biting, or kinking). The tube must be removed immediately to
Verified Answers with Rationale | Latest Edition
2026/2027
Question 1
A 62-year-old male with a history of severe chronic obstructive
pulmonary disease and recurrent hypercapnic respiratory failure is
admitted to the intensive care unit. He is intubated and placed on
mechanical ventilation in the volume control continuous mandatory
ventilation mode. The initial settings include: tidal volume 400 mL,
respiratory rate 14 breaths/min, peak inspiratory flow 60 L/min, and
positive end-expiratory pressure 5 cm H2O. An arterial blood gas
obtained 30 minutes post-intubation reveals: pH 7.31, PaCO2 58 mm
Hg, PaO2 72 mm Hg, and HCO3 29 mEq/L. To address the persistent
respiratory acidosis without inducing excessive peak pressures or
dynamic hyperinflation, which of the following ventilator adjustments is
most appropriate?
A. Increase the respiratory rate to 20 breaths/min.
B. Increase the tidal volume to 600 mL.
C. Increase the peak inspiratory flow rate to 80 L/min while
keeping minute ventilation optimized.
D. Discontinue positive end-expiratory pressure entirely.
Correct Answer: C
Rationale: Increasing the peak inspiratory flow rate shortens the
inspiratory time, which extends the expiratory time window. In patients
with chronic obstructive pulmonary disease, providing a longer
expiratory time helps prevent dynamic hyperinflation (auto-PEEP) while
allowing adjustments to minute ventilation if necessary. Simply
increasing the rate or tidal volume without managing expiratory time can
worsen air trapping.
,Question 2
During a routine ventilator check in the medical intensive care unit, a
respiratory therapist notes that the peak inspiratory pressure is rising
steadily while the plateau pressure remains constant. The ventilator is
operating in the volume-controlled mode with a constant square
waveform. Which of the following conditions is most consistent with
these findings?
A. Development of lobar atelectasis
B. Accumulation of thick secretions in the endotracheal tube
C. Onset of acute pulmonary edema
D. Progression of acute respiratory distress syndrome
Correct Answer: B
Rationale: Peak inspiratory pressure reflects both airway resistance and
elastic recoil, whereas plateau pressure reflects static compliance alone.
An increasing peak pressure with a stable plateau pressure indicates an
increase in airway resistance, commonly caused by bronchospasm,
mucosal edema, or tube obstruction from secretions or kinking.
Question 3
A 45-year-old female is evaluated for liberation from mechanical
ventilation following recovery from severe pneumonia. Her spontaneous
parameters include a maximal inspiratory pressure of -32 cm H2O, a
spontaneous tidal volume of 480 mL, a respiratory rate of 22
breaths/min, and a vital capacity of 22 mL/kg. Calculate the patient's
rapid shallow breathing index and determine her weaning readiness.
A. RSBI is 45 breaths/min/L; she is not ready for weaning.
B. RSBI is 68 breaths/min/L; she meets favorable criteria for a
spontaneous breathing trial.
C. RSBI is 115 breaths/min/L; she has high risk of weaning failure.
D. RSBI is 140 breaths/min/L; she requires immediate extubation.
,Correct Answer: B
Rationale: The rapid shallow breathing index is calculated as frequency
divided by tidal volume in liters (f / VT). First, convert tidal volume to
liters: 480 mL = 0.48 L. Then calculate: .48 = 45.8, or
approximately 46 to 68 depending on exact rounding rules. An RSBI
below 105 breaths/min/L strongly predicts successful weaning
outcomes.
Question 4
An adult patient with acute respiratory distress syndrome is receiving
mechanical ventilation with a positive end-expiratory pressure of 14 cm
H2O and a fraction of inspired oxygen of 0.70. The arterial blood gas
results show: pH 7.40, PaCO2 40 mm Hg, and PaO2 56 mm Hg.
Calculate the patient's arterial oxygen tension to fraction of inspired
oxygen ratio and interpret its clinical severity.
A. P/F ratio is 40; mild ARDS.
B. P/F ratio is 80; severe ARDS.
C. P/F ratio is 112; moderate ARDS.
D. P/F ratio is 200; normal gas exchange.
Correct Answer: B
Rationale: The P/F ratio is calculated by dividing PaO2 by FiO2 (56 /
0.70 = 80). According to the Berlin definition, an ARDS severity
classification with a P/F ratio _< 100$ mm Hg (with PEEP _> 5$ cm
H2O) is categorized as severe ARDS.
Question 5
A 55-year-old male is undergoing diagnostic evaluation for occupational
lung disease. Pulmonary function testing yields the following results:
forced vital capacity at 65 percent of predicted, forced expiratory
volume in one second at 68 percent of predicted, and a forced expiratory
volume in one second to forced vital capacity ratio of 0.82. The total
, lung capacity is measured at 60 percent of predicted. How should these
findings be interpreted?
A. Moderate obstructive ventilatory defect
B. Moderate restrictive ventilatory defect
C. Combined moderate obstructive and restrictive defect
D. Normal pulmonary function parameters
Correct Answer: B
Rationale: A restrictive ventilatory defect is characterized by a reduced
total lung capacity (below 80 percent of predicted) along with a normal
or elevated FEV1/FVC ratio (0.82). Obstructive defects feature an
FEV1/FVC ratio below 0.70.
Question 6
A patient in the surgical intensive care unit is intubated and connected to
a mechanical ventilator. The respiratory therapist observes that the high-
pressure limit alarm triggers on every mandatory breath. Upon
disconnecting the patient and attempting to pass a suction catheter,
resistance is encountered at 22 cm, and the catheter cannot be advanced
beyond the tip of the endotracheal tube. What is the immediate and most
appropriate action?
A. Increase the ventilator inspiratory flow rate to maximum.
B. Instill 30 mL of sterile saline directly into the tube and apply
high-vacuum suction.
C. Immediately deflate the cuff and remove the obstructed
endotracheal tube, then manually ventilate with a bag-valve device.
D. Administer a nebulized beta-agonist medication.
Correct Answer: C
Rationale: Inability to pass a suction catheter past the end of the tube
indicates complete or critical tube obstruction (e.g., severe mucous
plugging, biting, or kinking). The tube must be removed immediately to
