RRT RRT MCQ 3 β Questions and Answers
Question 1: A patient is receiving pressure support ventilation of 12 cmH2O. The respiratory therapist notes double-triggering. Which adjustment is MOST appropriate?
- Decrease pressure support level
- Increase inspiratory flow rate
- Adjust expiratory trigger sensitivity (cycle-off criterion) (Correct answer)
- Add PEEP to reduce work of breathing
Correct answer: Adjust expiratory trigger sensitivity (cycle-off criterion)
Double-triggering is often caused by the ventilator cycling off before the patient's neural inspiratory effort ends; adjusting the expiratory trigger (flow-cycle) sensitivity resolves this.
Question 2: A patient with myasthenia gravis is being evaluated for extubation. Which parameter is MOST predictive of successful weaning?
- FVC greater than 15 mL/kg (Correct answer)
- PaO2 greater than 60 mmHg on FiO2 0.40
- Maximum inspiratory pressure (MIP) more negative than -20 cmH2O
- Respiratory rate less than 25 breaths/min
Correct answer: FVC greater than 15 mL/kg
In neuromuscular disease, FVC >15β20 mL/kg is the primary threshold used to predict adequate ventilatory reserve for extubation.
Question 3: Which inhaled bronchodilator mechanism is responsible for long-acting beta-2 agonist (LABA) duration of action?
- Irreversible binding to beta-2 receptors
- Lipophilic side chains enabling receptor depot formation (Correct answer)
- Anticholinergic blockade of M3 receptors
- Inhibition of phosphodiesterase enzymes
Correct answer: Lipophilic side chains enabling receptor depot formation
LABAs like salmeterol have lipophilic side chains that anchor them in the cell membrane, creating a depot that allows prolonged receptor interaction lasting 12β24 hours.
Question 4: A neonate is born at 28 weeks gestation with grunting, nasal flaring, and retractions. Chest X-ray shows diffuse ground-glass opacification. The primary treatment is:
- Systemic corticosteroids
- Intratracheal surfactant administration (Correct answer)
- High-frequency jet ventilation immediately
- Broad-spectrum antibiotics
Correct answer: Intratracheal surfactant administration
Infant respiratory distress syndrome (IRDS) from surfactant deficiency is treated with exogenous surfactant replacement therapy administered intratracheally.
Question 5: During high-frequency oscillatory ventilation (HFOV), the primary determinant of oxygenation is:
- Frequency (Hz) setting
- Amplitude (ΞP) setting
- Mean airway pressure (MAP) (Correct answer)
- Inspiratory time percentage
Correct answer: Mean airway pressure (MAP)
In HFOV, mean airway pressure determines lung recruitment and oxygenation, while amplitude (ΞP) determines CO2 elimination.
Question 6: A patient with cystic fibrosis is admitted with acute exacerbation. Which airway clearance technique has the strongest evidence for routine use?
- Postural drainage with manual percussion
- Airway oscillating devices (flutter/Acapella) (Correct answer)
- Incentive spirometry
- Nasotracheal suctioning
Correct answer: Airway oscillating devices (flutter/Acapella)
Oscillating positive expiratory pressure devices (flutter valve, Acapella) are well-supported for mucus mobilization in cystic fibrosis and offer patient-administered convenience.
Question 7: Which finding on a capnography waveform is MOST consistent with bronchospasm?
- Plateau (phase III) slope that is horizontal
- Shark-fin shaped waveform with elevated plateau (Correct answer)
- Cardiogenic oscillations on the plateau
- Abrupt loss of ETCO2 waveform
Correct answer: Shark-fin shaped waveform with elevated plateau
Bronchospasm causes uneven alveolar emptying, producing a characteristic 'shark-fin' or upsloping phase III capnography waveform instead of the normal flat plateau.
RRT RRT MCQ 3
A patient is receiving pressure support ventilation of 12 cmH2O.
The respiratory therapist notes double-triggering.
Which adjustment is MOST appropriate?