What is the immediate management of sudden hypoxia during Video-Assisted Thoracic Surgery (VATS) with One-Lung Ventilation (OLV) in a patient in the right lateral position?

Management of Sudden Hypoxia During VATS with OLV in Right Lateral Position

Immediate management of sudden hypoxia during VATS with OLV requires prompt assessment of tube position, increasing FiO2 to 1.0, and applying CPAP to the non-ventilated lung while maintaining adequate neuromuscular blockade.

Immediate Actions

1. Increase FiO2 to 1.0

   • This provides maximal oxygen delivery to the ventilated lung 1
   • Ensure adequate oxygen reserves while troubleshooting

2. Check double-lumen tube position

   • Ensure deep neuromuscular blockade
   • Discontinue positive pressure ventilation with adjustable pressure-limiting valve open
   • Clamp the tracheal lumen angle piece and double-lumen tube
   • Apply HEPA filter to tracheal lumen before disconnection to prevent aerosol generation 2
   • Perform bronchoscopy to confirm correct tube position and rule out:
     • Malposition into wrong bronchus (occurs in 4.2% of cases) 2
     • Obstruction by secretions
     • Tube migration

3. Apply CPAP to non-ventilated (surgical) lung

   • If hypoxemia persists despite tube position confirmation:
     • Apply CPAP (5-10 cmH2O) to the non-dependent lung through a HEPA filter 2, 1
     • This reduces shunt fraction while still allowing surgical access

Secondary Interventions

If hypoxemia persists despite the above measures:

1. Optimize ventilation strategy for dependent lung

   • Apply PEEP (5-10 cmH2O) to the ventilated lung
   • Consider recruitment maneuvers for the ventilated lung
   • Use protective ventilation with tidal volumes of ≤8.5 mL/kg 2

2. Consider two-lung ventilation intermittently

   • If SpO2 falls below 90%, temporarily resume two-lung ventilation 3
   • Communicate with surgical team about the need for brief pauses

3. Consider alternative ventilation techniques

   • High-frequency jet ventilation through the bronchial blocker lumen for the non-dependent lung 4
   • This can improve oxygenation while still allowing surgical access

Pharmacological Interventions

1. Consider atropine administration

   • May enhance hypoxic pulmonary vasoconstriction (HPV) through muscarinic receptor blocking 5
   • Particularly useful if patient is on calcium channel blockers which may inhibit HPV

2. Ensure adequate depth of anesthesia and neuromuscular blockade

   • Inadequate muscle relaxation can cause ventilation-perfusion mismatch
   • Consider dexmedetomidine for its beneficial effects on oxygenation and lung function 2

Positional Considerations

1. Optimize patient position

   • The lateral decubitus position is more favorable for oxygenation during OLV than supine 3
   • Ensure proper positioning with adequate padding

2. Consider slight adjustments to position

   • A slight change in the degree of rotation may improve V/Q matching

Critical Considerations and Pitfalls

1. Time sensitivity

   • Hypoxemia can progress rapidly, especially in supine position (PaO2 may decrease to critical levels within 10-13 minutes) 3
   • Prompt intervention is essential to prevent hypoxic brain damage 2

2. Common causes of hypoxemia during OLV

   • Double-lumen tube malposition (most common and correctable cause)
   • Inadequate hypoxic pulmonary vasoconstriction
   • Pre-existing lung disease
   • Secretions obstructing the dependent lung

3. Medication effects

   • Calcium channel blockers (e.g., amlodipine) may inhibit hypoxic pulmonary vasoconstriction and worsen hypoxemia 5
   • Consider this in patients on antihypertensive medications

4. Surgical considerations

   • Communicate with surgical team about the need for interventions
   • Some maneuvers may temporarily interfere with surgical exposure

By following this systematic approach to managing sudden hypoxia during VATS with OLV, you can rapidly identify and address the cause while preventing potentially catastrophic hypoxic injury.