CFRN Respiratory Emergencies and Mechanical Ventilation 2 — Questions and Answers
Question 1: A patient's end-tidal CO2 (ETCO2) drops suddenly to near zero after intubation. What is the most likely cause?
- Right mainstem intubation
- Esophageal intubation (Correct answer)
- Kinked ETT
- Mucus plug
Correct answer: Esophageal intubation
A sudden drop of ETCO2 to near zero after intubation is the hallmark of esophageal intubation, as the esophagus does not produce CO2 in exhaled gas.
Question 2: What is the maximum recommended cuff pressure for an endotracheal tube to prevent tracheal mucosal ischemia?
- 10–15 cmH2O
- 20–30 cmH2O (Correct answer)
- 35–45 cmH2O
- 50–60 cmH2O
Correct answer: 20–30 cmH2O
ETT cuff pressure should be maintained at 20–30 cmH2O (15–22 mmHg) to seal the airway without compromising tracheal mucosal perfusion.
Question 3: Which finding is most consistent with a right mainstem bronchus intubation?
- Bilateral equal breath sounds and high ETCO2
- Absent left-sided breath sounds, high peak pressures, and SpO2 decline (Correct answer)
- Bilateral wheezing and low peak pressures
- No ETCO2 waveform
Correct answer: Absent left-sided breath sounds, high peak pressures, and SpO2 decline
Right mainstem intubation results in the left lung being bypassed, producing absent left-sided breath sounds, elevated peak pressures, and hypoxia.
Question 4: A transport patient with COPD has a PaCO2 of 78 mmHg and pH of 7.22. What ventilator adjustment addresses the respiratory acidosis?
- Increase PEEP
- Increase respiratory rate or tidal volume to increase minute ventilation (Correct answer)
- Decrease FiO2
- Add bronchodilators only
Correct answer: Increase respiratory rate or tidal volume to increase minute ventilation
Increasing minute ventilation (via rate or tidal volume) enhances CO2 elimination, raising pH and correcting respiratory acidosis.
Question 5: Which intervention is indicated for a massive hemothorax identified during air transport?
- Immediate needle decompression at the second ICS
- Chest tube insertion at the fourth or fifth ICS, anterior axillary line (Correct answer)
- High-dose furosemide IV
- Pericardiocentesis
Correct answer: Chest tube insertion at the fourth or fifth ICS, anterior axillary line
Massive hemothorax is managed with a large-bore chest tube inserted at the fourth or fifth ICS, anterior axillary line to drain blood and re-expand the lung.
Question 6: What does an increasing plateau pressure with unchanged peak pressure suggest in a ventilated patient during transport?
- Worsening bronchospasm
- Decreased lung or chest wall compliance (Correct answer)
- Endotracheal tube obstruction
- Auto-PEEP development
Correct answer: Decreased lung or chest wall compliance
Plateau pressure reflects lung and chest wall compliance; a rising plateau with stable peak pressure suggests decreased pulmonary compliance (e.g., worsening ARDS, pneumothorax, or fluid overload).
CFRN Respiratory Emergencies and Mechanical Ventilation 2
A patient's end-tidal CO2 (ETCO2) drops suddenly to near zero after intubation.
What is the most likely cause?