EDAIC Respiratory and Thoracic Anesthesia 5 — Questions and Answers
Question 1: During thoracic surgery in the lateral decubitus position, the dependent lung has INCREASED perfusion because of:
- Active bronchodilation of dependent airways
- Gravity-dependent redistribution of pulmonary blood flow (Correct answer)
- Increased HPV in the non-dependent lung
- Reduced FRC causing reflex vasoconstriction in the non-dependent lung
Correct answer: Gravity-dependent redistribution of pulmonary blood flow
Gravity directs more blood flow to the dependent (down) lung in the lateral position, creating the basis for matched ventilation and perfusion during two-lung ventilation.
Question 2: A 45-year-old woman scheduled for left VATS lobectomy has a predicted postoperative FEV1 of 52% and DLCO of 55%. According to ESTS guidelines, her surgical risk category is:
- Low risk — no further testing required (Correct answer)
- Moderate risk — consider cardiopulmonary exercise testing
- High risk — surgery contraindicated
- Very high risk — palliative treatment only
Correct answer: Low risk — no further testing required
Both predicted postoperative FEV1 and DLCO >40% place the patient in the low-risk category, and surgery may proceed without mandatory CPET.
Question 3: Which of the following most accurately describes the physiological effect of opening the chest during thoracotomy on the non-paralyzed patient breathing spontaneously?
- Paradoxical movement of the operative lung causing mediastinal swing (Correct answer)
- Immediate lung collapse due to loss of the thoracic bellows effect
- Compensatory hyperventilation by the contralateral lung
- Splinting of the ipsilateral hemidiaphragm causing atelectasis
Correct answer: Paradoxical movement of the operative lung causing mediastinal swing
In the awake spontaneously breathing patient, opening the chest causes the operative lung to collapse on inspiration and expand on expiration (paradoxical), with the mediastinum shifting toward the closed side.
Question 4: Which drug should be AVOIDED when treating HPV inhibition-related hypoxemia during OLV?
- Almitrine
- Phenylephrine
- Inhaled nitric oxide
- IV nitroglycerin (Correct answer)
Correct answer: IV nitroglycerin
Nitroglycerin is a pulmonary vasodilator that inhibits HPV systemically, worsening hypoxemia by increasing blood flow to the non-ventilated lung.
Question 5: The 'difficult airway' encountered during planned fiberoptic intubation for thoracic surgery is best managed by which backup strategy according to the DAS guidelines?
- Immediate surgical tracheostomy
- Supraglottic airway (LMA) insertion followed by fiber-optic intubation through it (Correct answer)
- Blind nasal intubation
- Cricothyroidotomy as first rescue option
Correct answer: Supraglottic airway (LMA) insertion followed by fiber-optic intubation through it
DAS guidelines recommend a second-generation supraglottic airway as a rescue device; fiberoptic intubation through the LMA can then establish a definitive airway.
Question 6: Intraoperative massive hemoptysis (>150 mL) during bronchoscopy for lung cancer staging is best immediately controlled by:
- Rigid bronchoscopy with argon plasma coagulation
- Emergent lung resection
- Immediate isolation of the bleeding lung with a DLT or bronchial blocker (Correct answer)
- Endobronchial thrombin injection via flexible bronchoscope
Correct answer: Immediate isolation of the bleeding lung with a DLT or bronchial blocker
Protecting the non-bleeding lung from blood aspiration by rapid lung isolation is the immediate priority to prevent bilateral flooding and asphyxiation.
Question 7: A patient is extubated after right upper lobectomy but develops progressive dyspnea 6 hours later with tracheal deviation to the right. Chest X-ray shows a large right pleural opacity. The diagnosis is:
- Right-sided pneumothorax
- Postpneumonectomy pulmonary edema
- Hemothorax from a bleeding intercostal vessel (Correct answer)
- Bronchial stump dehiscence with air leak
Correct answer: Hemothorax from a bleeding intercostal vessel
Tracheal deviation toward the operative side with a pleural opacity after lobectomy indicates hemothorax compressing the remaining right lung, consistent with uncontrolled bleeding.
EDAIC Respiratory and Thoracic Anesthesia 5
During thoracic surgery in the lateral decubitus position, the dependent lung has INCREASED perfusion because of: