Respiratory Therapy CRT RRT Certification Practice Exam Study Guide Updated
2026 🫁 | Verified Questions and Answers with Detailed Rationales | Pulmonary
Anatomy and Physiology, Oxygen Therapy and Delivery Devices, Mechanical
Ventilation Modes and Settings, Arterial Blood Gas (ABG) Interpretation, Airway
Management and Suctioning, Respiratory Assessment and Monitoring,
Cardiopulmonary Resuscitation (CPR), Pharmacology for Respiratory Care,
Infection Control and Patient Safety | Complete Exam Prep Resource for CRT and
RRT Certification Success
Question 1: Which structure is primarily responsible for warming, humidifying, and
filtering inspired air before it reaches the lower airways?
A. Alveoli
B. Bronchioles
C. Nasal cavity
D. Trachea
CORRECT ANSWER: C. Nasal cavity
RATIONALE:The nasal cavity contains turbinates and a rich vascular supply that warms
and humidifies inspired air, while nasal hairs and mucus trap particulate matter,
providing essential filtration before air reaches the lower respiratory tract. This
physiological function protects delicate alveolar structures from thermal injury,
desiccation, and pathogen invasion.
Question 2: A patient with severe COPD presents with a PaO₂ of 52 mmHg on room
air. Which oxygen delivery device is MOST appropriate to initiate therapy while
minimizing the risk of hypercapnia?
A. Non-rebreather mask at 15 L/min
B. Simple face mask at 8 L/min
C. Nasal cannula at 1-2 L/min
D. Venturi mask set at 24% FiO₂
CORRECT ANSWER: D. Venturi mask set at 24% FiO₂
RATIONALE:Patients with severe COPD and chronic hypercapnia may rely on hypoxic
drive for ventilation. A Venturi mask delivers a precise, low FiO₂ (24-28%), allowing
controlled oxygen titration to achieve target SpO₂ of 88-92% without suppressing
respiratory drive. Higher-flow devices risk worsening hypercapnia through the Haldane
effect and reduced hypoxic ventilatory response.
Question 3: During mechanical ventilation, a sudden increase in peak inspiratory
pressure with unchanged plateau pressure MOST likely indicates:
A. Decreased lung compliance
B. Bronchospasm or airway obstruction
C. Pneumothorax
D. Pulmonary edema
,CORRECT ANSWER: B. Bronchospasm or airway obstruction
RATIONALE:An isolated increase in peak inspiratory pressure (PIP) with stable plateau
pressure suggests increased airway resistance rather than decreased compliance.
Plateau pressure reflects alveolar pressure during an inspiratory hold; if unchanged,
lung/chest wall compliance is preserved. Bronchospasm, secretions, or kinked tubing
increase resistance, elevating PIP without affecting plateau pressure.
Question 4: Which arterial blood gas result is MOST consistent with acute,
uncompensated respiratory alkalosis?
A. pH 7.50, PaCO₂ 30 mmHg, HCO₃⁻ 24 mEq/L
B. pH 7.30, PaCO₂ 55 mmHg, HCO₃⁻ 26 mEq/L
C. pH 7.48, PaCO₂ 40 mmHg, HCO₃⁻ 30 mEq/L
D. pH 7.25, PaCO₂ 60 mmHg, HCO₃⁻ 22 mEq/L
CORRECT ANSWER: A. pH 7.50, PaCO₂ 30 mmHg, HCO₃⁻ 24 mEq/L
RATIONALE:Acute respiratory alkalosis features elevated pH (>7.45) with low PaCO₂
(<35 mmHg) and normal bicarbonate (22-26 mEq/L), indicating no metabolic
compensation has occurred. Option A matches this pattern. Option C shows metabolic
alkalosis; B and D represent respiratory acidosis with varying compensation.
Question 5: The primary mechanism of action for albuterol (salbutamol) in
respiratory therapy is:
A. Inhibition of phosphodiesterase
B. Stimulation of beta-2 adrenergic receptors
C. Blockade of muscarinic receptors
D. Suppression of leukotriene synthesis
CORRECT ANSWER: B. Stimulation of beta-2 adrenergic receptors
RATIONALE:Albuterol is a selective beta-2 agonist that binds to receptors on bronchial
smooth muscle, activating adenylate cyclase, increasing cAMP, and promoting smooth
muscle relaxation. This results in rapid bronchodilation. Phosphodiesterase inhibition is
the mechanism of methylxanthines; muscarinic blockade describes anticholinergics
like ipratropium; leukotriene suppression is characteristic of montelukast.
Question 6: Which finding on a flow-volume loop is MOST indicative of variable
extrathoracic upper airway obstruction?
A. Flattened inspiratory limb with preserved expiratory limb
B. Flattened expiratory limb with preserved inspiratory limb
C. Symmetrical flattening of both inspiratory and expiratory limbs
D. Scooped-out appearance of the expiratory limb
CORRECT ANSWER: A. Flattened inspiratory limb with preserved expiratory limb
,RATIONALE:In variable extrathoracic obstruction (e.g., vocal cord paralysis, tracheal
stenosis above thoracic inlet), negative intrathoracic pressure during inspiration
collapses the airway, flattening the inspiratory limb. Expiration generates positive
pressure that stents the airway open, preserving the expiratory limb. Fixed obstruction
flattens both limbs; intrathoracic variable obstruction flattens expiration; scooping
suggests obstructive lung disease.
Question 7: A neonate born at 28 weeks gestation develops grunting, nasal flaring,
and retractions shortly after birth. Chest X-ray shows a ground-glass appearance
with air bronchograms. Which intervention is MOST critical to initiate immediately?
A. Administer surfactant via endotracheal tube
B. Start CPAP at 5-6 cm H₂O
C. Initiate high-frequency oscillatory ventilation
D. Provide 100% oxygen via hood
CORRECT ANSWER: A. Administer surfactant via endotracheal tube
RATIONALE:This presentation is classic for respiratory distress syndrome (RDS) due to
surfactant deficiency in preterm infants. Early surfactant replacement therapy (within 1-
2 hours of life) reduces mortality, pneumothorax risk, and need for mechanical
ventilation. While CPAP is often used initially, surfactant administration is definitive
treatment for moderate-severe RDS with radiographic findings.
Question 8: Which parameter is the BEST indicator of adequate alveolar ventilation
in a mechanically ventilated patient?
A. Peak inspiratory pressure
B. Arterial PaCO₂
C. Oxygen saturation (SpO₂)
D. Tidal volume
CORRECT ANSWER: B. Arterial PaCO₂
RATIONALE:Alveolar ventilation directly determines PaCO₂ elimination via the alveolar
gas equation (PaCO₂ ∝ VCO₂/VA). A normal PaCO₂ (35-45 mmHg) confirms adequate
minute ventilation relative to metabolic CO₂ production. Peak pressure reflects
resistance/compliance; SpO₂ assesses oxygenation, not ventilation; tidal volume is a
set parameter that doesn't guarantee effective gas exchange if dead space is high.
Question 9: During chest physiotherapy for a patient with cystic fibrosis, which
technique is MOST effective for mobilizing secretions from the posterior segments
of the upper lobes?
A. Percussion over the anterior chest with patient supine
B. Vibration over the scapular area with patient sitting and leaning forward
C. Postural drainage with patient prone and head down
D. Huff coughing with patient in semi-Fowler's position
, CORRECT ANSWER: B. Vibration over the scapular area with patient sitting and
leaning forward
RATIONALE:The posterior segments of the upper lobes are best drained with the patient
sitting upright, leaning forward at a 30-degree angle. Vibration or percussion applied
over the scapular region (between spine and medial border of scapula) targets these
segments. Prone positioning drains posterior basal segments of lower lobes; anterior
chest percussion targets anterior segments.
Question 10: A patient with status asthmaticus is receiving continuous nebulized
albuterol. Which adverse effect requires IMMEDIATE intervention?
A. Mild tremor in hands
B. Heart rate increase from 80 to 110 bpm
C. Serum potassium of 3.0 mEq/L
D. Transient headache
CORRECT ANSWER: C. Serum potassium of 3.0 mEq/L
RATIONALE:Beta-2 agonists like albuterol cause intracellular shift of potassium,
potentially leading to significant hypokalemia. A level of 3.0 mEq/L increases risk of
cardiac arrhythmias, muscle weakness, and respiratory failure, requiring urgent
potassium replacement. Mild tremor, tachycardia, and headache are common,
expected side effects that typically don't warrant discontinuation of life-saving therapy.
Question 11: Which equation is used to calculate the alveolar-arterial (A-a) oxygen
gradient?
A. PAO₂ = (FiO₂ × [Patm - PH₂O]) - (PaCO₂ / R)
B. A-a gradient = PAO₂ - PaO₂
C. CaO₂ = (Hb × 1.34 × SaO₂) + (0.003 × PaO₂)
D. VD/VT = (PaCO₂ - PECO₂) / PaCO₂
CORRECT ANSWER: B. A-a gradient = PAO₂ - PaO₂
RATIONALE:The A-a gradient quantifies the difference between alveolar oxygen tension
(PAO₂, calculated using the alveolar gas equation in option A) and arterial oxygen
tension (PaO₂). An elevated gradient indicates impaired gas exchange due to V/Q
mismatch, shunt, or diffusion defect. Option C calculates arterial oxygen content;
option D calculates dead space fraction.
Question 12: In pressure support ventilation (PSV), which parameter is set by the
clinician to determine the level of ventilatory assistance?
A. Tidal volume
B. Respiratory rate
C. Inspiratory pressure above PEEP
D. Inspiratory time
CORRECT ANSWER: C. Inspiratory pressure above PEEP
2026 🫁 | Verified Questions and Answers with Detailed Rationales | Pulmonary
Anatomy and Physiology, Oxygen Therapy and Delivery Devices, Mechanical
Ventilation Modes and Settings, Arterial Blood Gas (ABG) Interpretation, Airway
Management and Suctioning, Respiratory Assessment and Monitoring,
Cardiopulmonary Resuscitation (CPR), Pharmacology for Respiratory Care,
Infection Control and Patient Safety | Complete Exam Prep Resource for CRT and
RRT Certification Success
Question 1: Which structure is primarily responsible for warming, humidifying, and
filtering inspired air before it reaches the lower airways?
A. Alveoli
B. Bronchioles
C. Nasal cavity
D. Trachea
CORRECT ANSWER: C. Nasal cavity
RATIONALE:The nasal cavity contains turbinates and a rich vascular supply that warms
and humidifies inspired air, while nasal hairs and mucus trap particulate matter,
providing essential filtration before air reaches the lower respiratory tract. This
physiological function protects delicate alveolar structures from thermal injury,
desiccation, and pathogen invasion.
Question 2: A patient with severe COPD presents with a PaO₂ of 52 mmHg on room
air. Which oxygen delivery device is MOST appropriate to initiate therapy while
minimizing the risk of hypercapnia?
A. Non-rebreather mask at 15 L/min
B. Simple face mask at 8 L/min
C. Nasal cannula at 1-2 L/min
D. Venturi mask set at 24% FiO₂
CORRECT ANSWER: D. Venturi mask set at 24% FiO₂
RATIONALE:Patients with severe COPD and chronic hypercapnia may rely on hypoxic
drive for ventilation. A Venturi mask delivers a precise, low FiO₂ (24-28%), allowing
controlled oxygen titration to achieve target SpO₂ of 88-92% without suppressing
respiratory drive. Higher-flow devices risk worsening hypercapnia through the Haldane
effect and reduced hypoxic ventilatory response.
Question 3: During mechanical ventilation, a sudden increase in peak inspiratory
pressure with unchanged plateau pressure MOST likely indicates:
A. Decreased lung compliance
B. Bronchospasm or airway obstruction
C. Pneumothorax
D. Pulmonary edema
,CORRECT ANSWER: B. Bronchospasm or airway obstruction
RATIONALE:An isolated increase in peak inspiratory pressure (PIP) with stable plateau
pressure suggests increased airway resistance rather than decreased compliance.
Plateau pressure reflects alveolar pressure during an inspiratory hold; if unchanged,
lung/chest wall compliance is preserved. Bronchospasm, secretions, or kinked tubing
increase resistance, elevating PIP without affecting plateau pressure.
Question 4: Which arterial blood gas result is MOST consistent with acute,
uncompensated respiratory alkalosis?
A. pH 7.50, PaCO₂ 30 mmHg, HCO₃⁻ 24 mEq/L
B. pH 7.30, PaCO₂ 55 mmHg, HCO₃⁻ 26 mEq/L
C. pH 7.48, PaCO₂ 40 mmHg, HCO₃⁻ 30 mEq/L
D. pH 7.25, PaCO₂ 60 mmHg, HCO₃⁻ 22 mEq/L
CORRECT ANSWER: A. pH 7.50, PaCO₂ 30 mmHg, HCO₃⁻ 24 mEq/L
RATIONALE:Acute respiratory alkalosis features elevated pH (>7.45) with low PaCO₂
(<35 mmHg) and normal bicarbonate (22-26 mEq/L), indicating no metabolic
compensation has occurred. Option A matches this pattern. Option C shows metabolic
alkalosis; B and D represent respiratory acidosis with varying compensation.
Question 5: The primary mechanism of action for albuterol (salbutamol) in
respiratory therapy is:
A. Inhibition of phosphodiesterase
B. Stimulation of beta-2 adrenergic receptors
C. Blockade of muscarinic receptors
D. Suppression of leukotriene synthesis
CORRECT ANSWER: B. Stimulation of beta-2 adrenergic receptors
RATIONALE:Albuterol is a selective beta-2 agonist that binds to receptors on bronchial
smooth muscle, activating adenylate cyclase, increasing cAMP, and promoting smooth
muscle relaxation. This results in rapid bronchodilation. Phosphodiesterase inhibition is
the mechanism of methylxanthines; muscarinic blockade describes anticholinergics
like ipratropium; leukotriene suppression is characteristic of montelukast.
Question 6: Which finding on a flow-volume loop is MOST indicative of variable
extrathoracic upper airway obstruction?
A. Flattened inspiratory limb with preserved expiratory limb
B. Flattened expiratory limb with preserved inspiratory limb
C. Symmetrical flattening of both inspiratory and expiratory limbs
D. Scooped-out appearance of the expiratory limb
CORRECT ANSWER: A. Flattened inspiratory limb with preserved expiratory limb
,RATIONALE:In variable extrathoracic obstruction (e.g., vocal cord paralysis, tracheal
stenosis above thoracic inlet), negative intrathoracic pressure during inspiration
collapses the airway, flattening the inspiratory limb. Expiration generates positive
pressure that stents the airway open, preserving the expiratory limb. Fixed obstruction
flattens both limbs; intrathoracic variable obstruction flattens expiration; scooping
suggests obstructive lung disease.
Question 7: A neonate born at 28 weeks gestation develops grunting, nasal flaring,
and retractions shortly after birth. Chest X-ray shows a ground-glass appearance
with air bronchograms. Which intervention is MOST critical to initiate immediately?
A. Administer surfactant via endotracheal tube
B. Start CPAP at 5-6 cm H₂O
C. Initiate high-frequency oscillatory ventilation
D. Provide 100% oxygen via hood
CORRECT ANSWER: A. Administer surfactant via endotracheal tube
RATIONALE:This presentation is classic for respiratory distress syndrome (RDS) due to
surfactant deficiency in preterm infants. Early surfactant replacement therapy (within 1-
2 hours of life) reduces mortality, pneumothorax risk, and need for mechanical
ventilation. While CPAP is often used initially, surfactant administration is definitive
treatment for moderate-severe RDS with radiographic findings.
Question 8: Which parameter is the BEST indicator of adequate alveolar ventilation
in a mechanically ventilated patient?
A. Peak inspiratory pressure
B. Arterial PaCO₂
C. Oxygen saturation (SpO₂)
D. Tidal volume
CORRECT ANSWER: B. Arterial PaCO₂
RATIONALE:Alveolar ventilation directly determines PaCO₂ elimination via the alveolar
gas equation (PaCO₂ ∝ VCO₂/VA). A normal PaCO₂ (35-45 mmHg) confirms adequate
minute ventilation relative to metabolic CO₂ production. Peak pressure reflects
resistance/compliance; SpO₂ assesses oxygenation, not ventilation; tidal volume is a
set parameter that doesn't guarantee effective gas exchange if dead space is high.
Question 9: During chest physiotherapy for a patient with cystic fibrosis, which
technique is MOST effective for mobilizing secretions from the posterior segments
of the upper lobes?
A. Percussion over the anterior chest with patient supine
B. Vibration over the scapular area with patient sitting and leaning forward
C. Postural drainage with patient prone and head down
D. Huff coughing with patient in semi-Fowler's position
, CORRECT ANSWER: B. Vibration over the scapular area with patient sitting and
leaning forward
RATIONALE:The posterior segments of the upper lobes are best drained with the patient
sitting upright, leaning forward at a 30-degree angle. Vibration or percussion applied
over the scapular region (between spine and medial border of scapula) targets these
segments. Prone positioning drains posterior basal segments of lower lobes; anterior
chest percussion targets anterior segments.
Question 10: A patient with status asthmaticus is receiving continuous nebulized
albuterol. Which adverse effect requires IMMEDIATE intervention?
A. Mild tremor in hands
B. Heart rate increase from 80 to 110 bpm
C. Serum potassium of 3.0 mEq/L
D. Transient headache
CORRECT ANSWER: C. Serum potassium of 3.0 mEq/L
RATIONALE:Beta-2 agonists like albuterol cause intracellular shift of potassium,
potentially leading to significant hypokalemia. A level of 3.0 mEq/L increases risk of
cardiac arrhythmias, muscle weakness, and respiratory failure, requiring urgent
potassium replacement. Mild tremor, tachycardia, and headache are common,
expected side effects that typically don't warrant discontinuation of life-saving therapy.
Question 11: Which equation is used to calculate the alveolar-arterial (A-a) oxygen
gradient?
A. PAO₂ = (FiO₂ × [Patm - PH₂O]) - (PaCO₂ / R)
B. A-a gradient = PAO₂ - PaO₂
C. CaO₂ = (Hb × 1.34 × SaO₂) + (0.003 × PaO₂)
D. VD/VT = (PaCO₂ - PECO₂) / PaCO₂
CORRECT ANSWER: B. A-a gradient = PAO₂ - PaO₂
RATIONALE:The A-a gradient quantifies the difference between alveolar oxygen tension
(PAO₂, calculated using the alveolar gas equation in option A) and arterial oxygen
tension (PaO₂). An elevated gradient indicates impaired gas exchange due to V/Q
mismatch, shunt, or diffusion defect. Option C calculates arterial oxygen content;
option D calculates dead space fraction.
Question 12: In pressure support ventilation (PSV), which parameter is set by the
clinician to determine the level of ventilatory assistance?
A. Tidal volume
B. Respiratory rate
C. Inspiratory pressure above PEEP
D. Inspiratory time
CORRECT ANSWER: C. Inspiratory pressure above PEEP
