Hemodynamic instability associated with dependent lung collapse in lateral position with kidney rest during laparoscopic nephroureterectomy

Intraoperative lung collapse is a rarely reported but potentially life-threatening event. We report an unusual case of hemodynamic instability secondary to collapse of the dependent lung. A 76-year-old man was scheduled for right laparoscopic nephroureterectomy. The anesthetized patient was placed in the left lateral position, and the kidney rest beneath iliac crest was elevated. Bilateral breath sounds were confirmed with auscultation. At 40 min after pneumoperitoneum, profound hypotension and high degree atrioventricular block occurred suddenly without desaturation. The operation stopped, and the patient was turned to supine position promptly. Then, blood pressure and electrocardiogram became normal. The chest x-ray showed the left lung collapse with proper position of endotracheal tube. We suspect that the tube moved gradually close to or into the main bronchus of nondependent lung after elevation of the kidney rest and/or pneumoperitoneum. Dynamic hyperinflation of nondependent lung might be the cause of hemodynamic instability.