One-lung anesthesia

Learning objectives

One-lung anesthesia defines the process of complete functional separation of the lungs
Involves ventilating one lung and collapsing the other
Facilitates certain types of surgery, but causes significant physiological disadvantages

Protective isolation
- Prevent contamination or spillage of infectious material (pus or secretions) from the contralateral lung
- Prevent massive hemorrhage
Control the distribution of ventilation between the two lungs in the presence of:
- Bronchopleural fistula
- Giant unilateral cyst/bulla
- Surgical opening of major airway
- Tracheobronchial tree disruption
Unilateral bronchopulmonary lavage (e.g., for alveolar proteinosis)
Video-assisted thoracoscopic surgery
Facilitate surgical exposure (e.g., pneumonectomy, lobectomy, thoracoscopy, esophageal surgery, thoracic aneurysm, thoracic spinal surgery)

Double lumen tube: Allows rapid transition between one-lung ventilation and two-lung ventilation, most commonly used technique
Bronchial blockers: Do not facilitate ventilation or suction distal to the blocker
Uncut tracheal tube: Can be advanced into the relevant main bronchus, generally only used in emergency situations
Papworth BiVent tube: New double lumen tube designed to facilitate rapid and reliable lung isolation using a bronchus blocker without endoscopic guidance

Hypoxemia is one of the most important complications encountered during one-lung anesthesia
Management of hypoxemia:
- Increase inspired oxygen to 100%
- Check the position of the tube with a fiberoptic bronchoscope
- Ensure adequate blood pressure and cardiac output
- Positive end-expiratory pressure 5-10 cmH2O to the dependent lung to decrease atelectasis and increase functional residual capacity
- Continuous positive airway pressure 5-10 cmH2O with 100% oxygen to the non-ventilated lung
- If hypoxemia is severe and does not resolve with the aforementioned steps: Abandon one-lung ventilation and intermittently ventilate the collapsed lung after warning the surgeon
- Early clamping of the appropriate pulmonary artery to stop the shunt