Hydrothorax during diagnostic laparoscopy

: An 83-yr-old, 44-kg woman with a 2-month history of abdominal distension received diagnostic laparoscopy. Except for chronic treated hypertension, she was healthy. The preoperative chest X-ray demonstrated small pleural effusion occupying the lower left hemithorax, but she did not present with dyspnea or chest pain. After premedication with intravenous ranitidine 50 mg, anesthesia was induced with thiopental 150 mg, vecuronium 7 mg and maintained by 1-2% sevoflurane in 50% N2O/O2. SpO2 decreased after insufflation of CO2, but breath sound was audible on both lungs. At completion of operation, chest X-ray revealed the left hemilateral hydrothorax and 650 ml of pleural fluid was suctioned. Blood gas improved and the tracheal tube was removed. The diagnosis of tuberculous peritonitis was established by the demonstration of granulomas of the peritoneum. We speculated on four reasons for the increased pleural effusion on the left thorax: 1) Increase of systemic and capillary pressure caused by CO2 insufflation. 2) Increase of capillary permeability by tuberculous pleuritis. 3) Decrease of colloid osmotic pressure by hypoalbuminemia. 4) Decreased pleural fluid removal because of venous compression caused by increased intrathoracic pressure. Peritoneal insufflation of CO2 to create the pneumoperitoneum may induce hydrothorax in patients with tuberculous pleuritis.