RRT RRT Knowledge 5 — Questions and Answers
Question 1: A patient with a tracheostomy tube in place develops subcutaneous emphysema around the stoma site and decreased breath sounds. The MOST likely cause is:
- Tracheomalacia
- Tracheoesophageal fistula
- False passage or paratracheal tube placement (Correct answer)
- Tracheal stenosis
Correct answer: False passage or paratracheal tube placement
Subcutaneous emphysema with decreased breath sounds after tracheostomy placement suggests the tube has created a false passage outside the trachea.
Question 2: The Fick equation for cardiac output requires which of the following variables?
- Heart rate, stroke volume, and SVR
- VO2, CaO2, and CvO2 (Correct answer)
- PaO2, SaO2, and hemoglobin
- PCWP, CVP, and MAP
Correct answer: VO2, CaO2, and CvO2
The Fick equation is CO = VO2 / (CaO2 − CvO2), requiring oxygen consumption and the arteriovenous oxygen content difference.
Question 3: A mechanically ventilated patient has an end-tidal CO2 (EtCO2) of 28 mmHg and a PaCO2 of 44 mmHg. The arterial-to-end-tidal CO2 gradient of 16 mmHg MOST likely indicates:
- Hyperventilation
- Increased dead space ventilation (Correct answer)
- Metabolic alkalosis
- Accurate capnography calibration
Correct answer: Increased dead space ventilation
A large PaCO2–EtCO2 gradient (normally ≤5 mmHg) indicates increased dead space ventilation, where exhaled CO2 is diluted by non-perfused alveolar gas.
Question 4: Which inhaled medication is classified as a long-acting muscarinic antagonist (LAMA) and is used in COPD maintenance therapy?
- Ipratropium bromide
- Tiotropium bromide (Correct answer)
- Formoterol fumarate
- Salmeterol xinafoate
Correct answer: Tiotropium bromide
Tiotropium is a once-daily LAMA that provides sustained bronchodilation by blocking M3 muscarinic receptors, used as COPD maintenance therapy.
Question 5: A patient requires nitric oxide (iNO) therapy for pulmonary hypertension. The MOST important monitoring parameter specific to iNO administration is:
- Serum potassium levels
- Methemoglobin levels (Correct answer)
- End-tidal CO2 waveform
- Peak inspiratory pressure
Correct answer: Methemoglobin levels
Inhaled nitric oxide oxidizes hemoglobin to methemoglobin, which cannot carry oxygen; methemoglobin levels must be monitored and kept below 5%.
Question 6: During a bronchoscopy-guided BAL (bronchoalveolar lavage), the respiratory therapist should maintain SpO2 above what minimum threshold throughout the procedure?
- 85%
- 88%
- 90% (Correct answer)
- 95%
Correct answer: 90%
SpO2 should be maintained at or above 90% during BAL; supplemental oxygen should be increased pre-procedure and the procedure paused if desaturation occurs.
Question 7: An adult patient weighing 70 kg is being initiated on high-flow nasal cannula (HFNC) for hypoxemic respiratory failure. An appropriate starting flow rate is:
- 10–15 L/min
- 20–25 L/min
- 40–60 L/min (Correct answer)
- 80–100 L/min
Correct answer: 40–60 L/min
HFNC is typically initiated at 40–60 L/min in adults to ensure flows exceed peak inspiratory demand and wash out nasopharyngeal dead space.
RRT RRT Knowledge 5
A patient with a tracheostomy tube in place develops subcutaneous emphysema around the stoma site and decreased breath sounds.
The MOST likely cause is: