RRT Respiratory Therapy 3 — Questions and Answers
Question 1: A patient with myasthenia gravis crisis has a vital capacity of 12 mL/kg. The appropriate action is:
- Increase supplemental oxygen and monitor
- Begin BiPAP at IPAP 10 / EPAP 5
- Initiate intubation and mechanical ventilation (Correct answer)
- Administer nebulized albuterol
Correct answer: Initiate intubation and mechanical ventilation
The 20-30-40 rule recommends intubation when VC falls below 20 mL/kg in neuromuscular patients; 12 mL/kg is critical.
Question 2: Auto-PEEP (intrinsic PEEP) is MOST commonly caused by:
- High inspiratory flow rates
- Insufficient expiratory time leading to air trapping (Correct answer)
- High tidal volume ventilation
- Use of pressure support mode
Correct answer: Insufficient expiratory time leading to air trapping
Auto-PEEP results from incomplete exhalation due to insufficient expiratory time, causing air trapping and dynamic hyperinflation.
Question 3: Which condition is associated with a decreased DLCO (diffusing capacity) with normal spirometry?
- Asthma
- Obesity
- Pulmonary hypertension (Correct answer)
- Neuromuscular disease
Correct answer: Pulmonary hypertension
Pulmonary hypertension reduces the pulmonary capillary blood volume available for gas exchange, lowering DLCO despite normal airflow.
Question 4: The recommended initial tidal volume for lung-protective ventilation in ARDS is:
- 10–12 mL/kg IBW
- 6–8 mL/kg IBW (Correct answer)
- 4–5 mL/kg IBW
- 8–10 mL/kg IBW
Correct answer: 6–8 mL/kg IBW
The ARDSNet protocol recommends 6 mL/kg ideal body weight (IBW) with a goal plateau pressure ≤ 30 cmH2O.
Question 5: A flow-volume loop shows a fixed flattening of both inspiratory and expiratory limbs. This pattern suggests:
- Variable extrathoracic obstruction
- Variable intrathoracic obstruction
- Fixed upper airway obstruction (Correct answer)
- Restrictive lung disease
Correct answer: Fixed upper airway obstruction
Fixed obstruction (e.g., tracheal stenosis) flattens both limbs equally because the lesion does not change size with pressure changes.
Question 6: When performing nasotracheal suctioning, the catheter should be inserted to what approximate depth in an adult?
- 10–12 cm
- 16–20 cm (Correct answer)
- 6–8 cm
- 22–26 cm
Correct answer: 16–20 cm
The nasotracheal catheter is advanced approximately 16–20 cm past the naris to reach the trachea in most adults.
Question 7: Which maneuver is used to assess expiratory flow limitation and auto-PEEP during mechanical ventilation?
- Inspiratory hold (plateau pressure)
- Expiratory hold (end-expiratory occlusion) (Correct answer)
- Recruitment maneuver
- Pressure-time product calculation
Correct answer: Expiratory hold (end-expiratory occlusion)
An expiratory hold occludes the expiratory valve at end-exhalation, allowing trapped pressure (auto-PEEP) to equilibrate and be measured.
RRT Respiratory Therapy 3
A patient with myasthenia gravis crisis has a vital capacity of 12 mL/kg.
The appropriate action is: