NBRC RRT Exam Prep | Registered Respiratory Therapist
Practice Questions, Clinical Scenarios & Detailed Rationales
2026/2027
QUESTION 1
A 68-year-old male with severe ARDS is being mechanically ventilated in
volume-control CMV with a set tidal volume of 400 mL (6 mL/kg IBW).
His current ABG shows pH 7.32, PaCO2 48 mmHg, PaO2 55 mmHg, and
HCO3 24 mEq/L on an FiO2 of 0.70 and PEEP of 12 cmH2O. The plateau
pressure is 30 cmH2O. According to the ARDSNet protocol, what is the
most appropriate next step to improve oxygenation?
• A. Increase the tidal volume to 8 mL/kg IBW
• B. Increase the PEEP to 14 cmH2O and decrease FiO2 to maintain
safe limits
• C. Switch to pressure-control ventilation with a driving pressure of
20 cmH2O
• D. Initiate inverse ratio ventilation with an I:E ratio of 2:1
Correct Answer: B. Increase the PEEP to 14 cmH2O and decrease FiO2
to maintain safe limits.
Detailed Rationale: Based on the ARDSNet PEEP/FiO2 titration tables,
when a patient on an FiO2 of 0.70 has refractory hypoxemia (PaO2 55
mmHg) and the plateau pressure is already at the safe ceiling of 30
cmH2O, increasing PEEP while adjusting FiO2 helps recruit alveoli
without increasing volutrauma. Increasing tidal volume would raise
plateau pressure above 30 cmH2O, violating lung-protective strategies.
,QUESTION 2
A patient in the ICU has a pulmonary artery catheter inserted following
a motor vehicle crash. Hemodynamic parameters show: CVP 2 mmHg,
PAP 18/6 mmHg, PCWP 4 mmHg, Cardiac Output 7.8 L/min, and
Systemic Vascular Resistance (SVR) 550 dynes·sec·cm⁻⁵. Which
condition is most consistent with these findings?
• A. Cardiogenic shock
• B. Hypovolemic shock
• C. Septic shock
• D. Pulmonary embolism
Correct Answer: C. Septic shock.
Detailed Rationale: Septic shock is characterized by profound systemic
vasodilation (low SVR), leading to a hyperdynamic state with high
cardiac output. Filling pressures (CVP and PCWP) are low due to
vasodilation and relative or absolute hypovolemia. In contrast,
cardiogenic shock shows high filling pressures and low cardiac output,
while hypovolemic shock shows low filling pressures with high SVR and
low cardiac output.
QUESTION 3
An adult male patient undergoing a spontaneous breathing trial (SBT)
via T-piece begins to exhibit tachypnea (RR 34 breaths/min),
diaphoresis, use of accessory muscles, and an SpO2 drop from 96% to
88% after 20 minutes. What is the most appropriate action?
• A. Continue the SBT for another 30 minutes to assess endurance.
, • B. Terminate the SBT and return the patient to ventilator support.
• C. Increase the FiO2 by 20% and continue the SBT.
• D. Switch the patient immediately to pressure support of 15
cmH2O.
Correct Answer: B. Terminate the SBT and return the patient to
ventilator support.
Detailed Rationale: The development of tachypnea, diaphoresis,
accessory muscle use, and desaturation are classic signs of SBT failure.
The SBT should be terminated immediately, and the patient should be
returned to a supportive mode to rest.
QUESTION 4
While performing an inspiratory hold maneuver on an adult male
receiving volume-controlled ventilation, the respiratory therapist notes
a Peak Inspiratory Pressure (PIP) of 34 cmH2O and a Plateau Pressure
(Pplat) of 22 cmH2O. What do these findings indicate?
• A. Decreased lung compliance
• B. Increased airway resistance
• C. Normal mechanical properties
• D. Alveolar overdistension
Correct Answer: B. Increased airway resistance.
Detailed Rationale: Airway resistance is reflected by the transairway
pressure gradient (PIP minus Pplat). A normal gradient is around 5 to 10
cmH2O. Here, the gradient is 12 cmH2O (34 minus 22), indicating
elevated airway resistance (e.g., bronchospasm, mucus plugging, or a
, kinked tube), whereas lung compliance is reflected by the plateau
pressure and is within normal limits.
QUESTION 5
A 54-year-old female with chronic hypercapnic respiratory failure due to
severe COPD is admitted with an acute exacerbation. An ABG drawn on
room air shows pH 7.33, PaCO2 68 mmHg, PaO2 52 mmHg, and HCO3
36 mEq/L. What is the primary clinical interpretation?
• A. Acute respiratory acidosis
• B. Chronic respiratory acidosis with complete compensation
• C. Acute-on-chronic respiratory acidosis with moderate hypoxemia
• D. Metabolic alkalosis with respiratory compensation
Correct Answer: C. Acute-on-chronic respiratory acidosis with moderate
hypoxemia.
Detailed Rationale: The elevated bicarbonate (36 mEq/L) and high
baseline PaCO2 indicate long-standing renal compensation for chronic
hypercapnia (chronic respiratory acidosis). However, the acidemia (pH
7.33) and further rise in PaCO2 indicate an acute worsening on top of
the chronic baseline, accompanied by moderate hypoxemia (PaO2 52
mmHg).
QUESTION 6
A respiratory therapist is evaluating a patient on a mechanical ventilator
and suspects auto-PEEP. Which maneuver should the therapist perform
to measure total PEEP (intrinsic PEEP)?
• A. Expiratory hold maneuver
Practice Questions, Clinical Scenarios & Detailed Rationales
2026/2027
QUESTION 1
A 68-year-old male with severe ARDS is being mechanically ventilated in
volume-control CMV with a set tidal volume of 400 mL (6 mL/kg IBW).
His current ABG shows pH 7.32, PaCO2 48 mmHg, PaO2 55 mmHg, and
HCO3 24 mEq/L on an FiO2 of 0.70 and PEEP of 12 cmH2O. The plateau
pressure is 30 cmH2O. According to the ARDSNet protocol, what is the
most appropriate next step to improve oxygenation?
• A. Increase the tidal volume to 8 mL/kg IBW
• B. Increase the PEEP to 14 cmH2O and decrease FiO2 to maintain
safe limits
• C. Switch to pressure-control ventilation with a driving pressure of
20 cmH2O
• D. Initiate inverse ratio ventilation with an I:E ratio of 2:1
Correct Answer: B. Increase the PEEP to 14 cmH2O and decrease FiO2
to maintain safe limits.
Detailed Rationale: Based on the ARDSNet PEEP/FiO2 titration tables,
when a patient on an FiO2 of 0.70 has refractory hypoxemia (PaO2 55
mmHg) and the plateau pressure is already at the safe ceiling of 30
cmH2O, increasing PEEP while adjusting FiO2 helps recruit alveoli
without increasing volutrauma. Increasing tidal volume would raise
plateau pressure above 30 cmH2O, violating lung-protective strategies.
,QUESTION 2
A patient in the ICU has a pulmonary artery catheter inserted following
a motor vehicle crash. Hemodynamic parameters show: CVP 2 mmHg,
PAP 18/6 mmHg, PCWP 4 mmHg, Cardiac Output 7.8 L/min, and
Systemic Vascular Resistance (SVR) 550 dynes·sec·cm⁻⁵. Which
condition is most consistent with these findings?
• A. Cardiogenic shock
• B. Hypovolemic shock
• C. Septic shock
• D. Pulmonary embolism
Correct Answer: C. Septic shock.
Detailed Rationale: Septic shock is characterized by profound systemic
vasodilation (low SVR), leading to a hyperdynamic state with high
cardiac output. Filling pressures (CVP and PCWP) are low due to
vasodilation and relative or absolute hypovolemia. In contrast,
cardiogenic shock shows high filling pressures and low cardiac output,
while hypovolemic shock shows low filling pressures with high SVR and
low cardiac output.
QUESTION 3
An adult male patient undergoing a spontaneous breathing trial (SBT)
via T-piece begins to exhibit tachypnea (RR 34 breaths/min),
diaphoresis, use of accessory muscles, and an SpO2 drop from 96% to
88% after 20 minutes. What is the most appropriate action?
• A. Continue the SBT for another 30 minutes to assess endurance.
, • B. Terminate the SBT and return the patient to ventilator support.
• C. Increase the FiO2 by 20% and continue the SBT.
• D. Switch the patient immediately to pressure support of 15
cmH2O.
Correct Answer: B. Terminate the SBT and return the patient to
ventilator support.
Detailed Rationale: The development of tachypnea, diaphoresis,
accessory muscle use, and desaturation are classic signs of SBT failure.
The SBT should be terminated immediately, and the patient should be
returned to a supportive mode to rest.
QUESTION 4
While performing an inspiratory hold maneuver on an adult male
receiving volume-controlled ventilation, the respiratory therapist notes
a Peak Inspiratory Pressure (PIP) of 34 cmH2O and a Plateau Pressure
(Pplat) of 22 cmH2O. What do these findings indicate?
• A. Decreased lung compliance
• B. Increased airway resistance
• C. Normal mechanical properties
• D. Alveolar overdistension
Correct Answer: B. Increased airway resistance.
Detailed Rationale: Airway resistance is reflected by the transairway
pressure gradient (PIP minus Pplat). A normal gradient is around 5 to 10
cmH2O. Here, the gradient is 12 cmH2O (34 minus 22), indicating
elevated airway resistance (e.g., bronchospasm, mucus plugging, or a
, kinked tube), whereas lung compliance is reflected by the plateau
pressure and is within normal limits.
QUESTION 5
A 54-year-old female with chronic hypercapnic respiratory failure due to
severe COPD is admitted with an acute exacerbation. An ABG drawn on
room air shows pH 7.33, PaCO2 68 mmHg, PaO2 52 mmHg, and HCO3
36 mEq/L. What is the primary clinical interpretation?
• A. Acute respiratory acidosis
• B. Chronic respiratory acidosis with complete compensation
• C. Acute-on-chronic respiratory acidosis with moderate hypoxemia
• D. Metabolic alkalosis with respiratory compensation
Correct Answer: C. Acute-on-chronic respiratory acidosis with moderate
hypoxemia.
Detailed Rationale: The elevated bicarbonate (36 mEq/L) and high
baseline PaCO2 indicate long-standing renal compensation for chronic
hypercapnia (chronic respiratory acidosis). However, the acidemia (pH
7.33) and further rise in PaCO2 indicate an acute worsening on top of
the chronic baseline, accompanied by moderate hypoxemia (PaO2 52
mmHg).
QUESTION 6
A respiratory therapist is evaluating a patient on a mechanical ventilator
and suspects auto-PEEP. Which maneuver should the therapist perform
to measure total PEEP (intrinsic PEEP)?
• A. Expiratory hold maneuver
