EDAIC Respiratory and Thoracic Anesthesia 3 — Questions and Answers
Question 1: Bronchospasm during thoracic surgery is LEAST likely to respond to which intervention?
- Deepening volatile anesthetic depth
- IV ketamine
- Inhaled salbutamol via the breathing circuit
- IV rocuronium (Correct answer)
Correct answer: IV rocuronium
Neuromuscular blocking agents have no bronchodilatory effect; bronchospasm requires agents that relax airway smooth muscle via adrenergic or anti-cholinergic mechanisms.
Question 2: During video-assisted thoracoscopic surgery (VATS), inadequate lung collapse despite a correctly positioned DLT is most efficiently addressed by:
- Insufflating CO2 into the pleural space at low pressure (Correct answer)
- Increasing PEEP on the ventilated lung
- Applying 5 cmH2O CPAP to the collapsed lung
- Switching to a single-lumen tube with bronchial blocker
Correct answer: Insufflating CO2 into the pleural space at low pressure
Low-pressure CO2 insufflation (up to 8 mmHg) into the pleural cavity rapidly collapses the operative lung and improves surgical visualization when passive collapse is incomplete.
Question 3: A bronchial blocker is preferred over a double-lumen tube in which clinical scenario?
- Left pneumonectomy planned
- Patient with a difficult airway already intubated with a size 7.5 single-lumen tube (Correct answer)
- Need for postoperative differential lung ventilation
- Surgeon requiring rapid lung re-expansion
Correct answer: Patient with a difficult airway already intubated with a size 7.5 single-lumen tube
A bronchial blocker can be advanced through an existing single-lumen ETT under fiberoptic guidance, avoiding the need to exchange to a larger tube in a difficult airway.
Question 4: The phenomenon of 'auto-PEEP' during one-lung ventilation is most commonly caused by:
- Excessive inspiratory flow rate
- Inadequate expiratory time leading to air trapping (Correct answer)
- Endobronchial mucus plugging the ventilated bronchus
- High FiO2 causing absorption atelectasis
Correct answer: Inadequate expiratory time leading to air trapping
Auto-PEEP (intrinsic PEEP) develops when the next breath begins before full exhalation, trapping gas and increasing end-expiratory lung volume, particularly in COPD patients.
Question 5: Which parameter best predicts postoperative pulmonary complications after lung resection?
- Preoperative FVC alone
- Diffusing capacity for carbon monoxide (DLCO) (Correct answer)
- Preoperative PaCO2 > 45 mmHg
- Maximum inspiratory pressure (MIP)
Correct answer: Diffusing capacity for carbon monoxide (DLCO)
DLCO reflects gas exchange surface area and pulmonary vascular reserve; predicted postoperative DLCO <40% correlates strongly with postoperative morbidity and mortality.
Question 6: A patient with a large right-sided pleural effusion requires thoracentesis under general anesthesia. During drainage, she suddenly becomes hypotensive and dyspneic. The most likely diagnosis is:
- Tension pneumothorax on the right
- Re-expansion pulmonary edema (Correct answer)
- Hemorrhagic shock from intercostal vessel laceration
- Vasovagal syncope
Correct answer: Re-expansion pulmonary edema
Rapid drainage of large pleural effusions can cause re-expansion pulmonary edema as chronically collapsed lung tissue rapidly fills with fluid, releasing inflammatory mediators.
Question 7: In thoracic epidural analgesia for open thoracotomy, the optimal dermatomal level of catheter insertion is:
- C7-T1
- T1-T4
- T4-T8 (Correct answer)
- T8-T12
Correct answer: T4-T8
Thoracic epidural catheters placed at T4-T8 provide analgesia centered on the thoracotomy incision, optimizing pain control and preserving respiratory function.
EDAIC Respiratory and Thoracic Anesthesia 3
Bronchospasm during thoracic surgery is LEAST likely to respond to which intervention?