Real-Time Digital Quantification of Air-Leak Flow to Guide Endobronchial Watanabe Spigot Placement for Persistent Air Leak: A 12-Year Single-Center Experience.

Objective　To describe the real-time digital quantification of the air-leak flow during endobronchial Watanabe spigot (EWS) placement for persistent air leak and to relate the quantified flow to the clinical outcomes.Methods　The primary outcome was the immediate change in the air-leak flow before and after EWS placement in the digital group. The secondary outcomes were leak-site identification, single-session cure, final cessation without surgery, chest tube duration, and safety. We also related the post-placement flow and the interval between the fulfilment of the removal criterion and actual removal to the drainage course. The between-group comparison was exploratory.Patients　Twenty-seven consecutive patients with pneumothorax or empyema with bronchopleural fistula undergoing EWS placement between March 2014 and January 2026; 18 were managed with digital drainage (Thopaz/Thopaz+) and 9 with conventional suction, at the physician's discretion.Results　The air-leak flow decreased immediately after EWS placement [median 525 (interquartile range 200-1,000) to 5 (0-138) mL/min]. The immediate flow did not predict whether the tube was removed (76.9% at 100 mL/min or less vs. 80.0% above), but did predict how quickly: median 9, 12.5, and 16.5 days for flows of 0, 100 mL/min or less, and higher. The removal criterion (20 mL/min or less) was met a median of 0 days after placement, yet the tube stayed for 6.5 days longer. The responsible bronchus was identified in 66.7% of patients, and final cessation without surgery was achieved in 77.8% of patients.Conclusion　Real-time digital quantification confirmed bronchial occlusion and predicted drainage duration but not eventual clinical success. The interval between the fulfilment of the removal criterion and actual removal warrants a prospective study.