RRT RRT MCQ 4 — Questions and Answers
Question 1: A patient on mechanical ventilation develops decreased compliance and new bilateral infiltrates 48 hours post-intubation. Which lung-protective strategy parameter should be monitored to prevent VILI?
- Peak inspiratory pressure below 30 cmH2O
- Plateau pressure below 30 cmH2O (Correct answer)
- Mean airway pressure below 20 cmH2O
- PEEP below 10 cmH2O
Correct answer: Plateau pressure below 30 cmH2O
Plateau pressure reflects alveolar distending pressure and should be kept below 30 cmH2O to minimize ventilator-induced lung injury (VILI).
Question 2: A patient has the following ABG: pH 7.50, PaCO2 30 mmHg, HCO3 23 mEq/L. What is the acid-base interpretation?
- Acute respiratory alkalosis (Correct answer)
- Metabolic alkalosis with respiratory compensation
- Mixed respiratory alkalosis and metabolic alkalosis
- Chronic respiratory alkalosis
Correct answer: Acute respiratory alkalosis
A high pH with low PaCO2 and normal bicarbonate indicates acute respiratory alkalosis with no metabolic compensation yet.
Question 3: When performing a therapeutic bronchoscopy to remove a mucus plug, what is the MAXIMUM safe duration of each suction pass?
- 5 seconds
- 10–15 seconds (Correct answer)
- 30 seconds
- 60 seconds
Correct answer: 10–15 seconds
Each suction pass during bronchoscopy should be limited to 10–15 seconds to prevent significant oxygen desaturation and mucosal trauma.
Question 4: A patient is receiving BiPAP with IPAP 14 cmH2O and EPAP 6 cmH2O. What is the effective pressure support being delivered?
- 6 cmH2O
- 8 cmH2O (Correct answer)
- 14 cmH2O
- 20 cmH2O
Correct answer: 8 cmH2O
Effective pressure support in BiPAP equals IPAP minus EPAP (14 − 6 = 8 cmH2O), which drives tidal volume delivery.
Question 5: Which pulse oximetry reading is MOST likely to be falsely elevated (overestimated) in a patient with carbon monoxide poisoning?
- SaO2 by co-oximetry
- SpO2 by standard pulse oximetry (Correct answer)
- PaO2 by arterial blood gas
- FiO2 delivered by oxygen mask
Correct answer: SpO2 by standard pulse oximetry
Standard pulse oximetry cannot distinguish oxyhemoglobin from carboxyhemoglobin, so SpO2 reads falsely high in CO poisoning; co-oximetry is required for accurate measurement.
Question 6: A patient with obstructive sleep apnea is titrated on CPAP. The recommended first-line CPAP pressure titration endpoint is elimination of which event?
- Hypopneas only
- Obstructive apneas, hypopneas, and snoring (Correct answer)
- Central apneas only
- Oxygen desaturations below 88%
Correct answer: Obstructive apneas, hypopneas, and snoring
CPAP titration aims to eliminate obstructive apneas, hypopneas, respiratory effort-related arousals (RERAs), and snoring to achieve an AHI <5.
Question 7: Which ventilator mode provides a guaranteed tidal volume while allowing variable inspiratory flow to meet patient demand?
- Pressure Control Ventilation (PCV)
- Volume-Assured Pressure Support (VAPS) (Correct answer)
- Synchronized Intermittent Mandatory Ventilation (SIMV)
- Airway Pressure Release Ventilation (APRV)
Correct answer: Volume-Assured Pressure Support (VAPS)
Volume-assured pressure support (VAPS/AVAPS) automatically adjusts pressure support to guarantee a target tidal volume while still allowing demand-driven flow delivery.
RRT RRT MCQ 4
A patient on mechanical ventilation develops decreased compliance and new bilateral infiltrates 48 hours post-intubation.
Which lung-protective strategy parameter should be monitored to prevent VILI?