Assessment of Postoperative Chylothorax Volume Threshold Associated with Failed Conservative Management

Management of postoperative chylothorax typically involves a stepwise strategy of initial conservative management followed by lymphangiography and reoperation when conservative management fails. This study tested the hypothesis that high-volume chylothorax drainage over the first 48 hours is associated with failure of conservative management.

Our institutional database was queried for patients treated between 2009 and 2024 who developed chylothorax following lung, foregut, or mediastinal surgery and underwent initial conservative management. Patients were stratified according to whether the chylothorax resolved with conservative management vs intervention with lymphangiography and/or reoperation. Daily thoracostomy tube drainage was evaluated, and a 48-hour chylothorax volume cutoff point associated with failure of conservative management was calculated by using Youden's index from the receiver operating characteristic curve. Predictors of failed conservative management were estimated using multivariable logistic regression.

Seventy-seven patients experienced postoperative chylothorax, including 43 (56%) after lung resection, 22 (29%) after esophageal surgery, and 12 (16%) after mediastinal surgery. Forty-eight (62%) patients were successfully managed conservatively and 29 (38%) patients required intervention. Daily chylothorax drainage was notably lower in patients who required conservative management. The area under the receiver operating characteristic curve was 0.75, and the 48-hour chylothorax volume cutoff point was 1110 mL based on Youden's index. This cutoff was associated with a nearly 4-fold increased risk of failed conservative management (adjusted odds ratio, 3.84, P = .023).

Patients who develop postoperative chylothorax with drainage >1100 mL over the first 48 hours should be considered for early intervention with lymphangiography or reoperation, given the likelihood of failing conservative management.