How to distinguish an active air leak from a pleural space effect.

ABSTRACT

AIM: We aimed to distinguish a pleural space effect from an active air leak, using a digital chest drain system that provided continuous air flow and pleural pressure checks. METHODS: between March 2010 and October 2011, we employed 144 digital drains for 138 thoracic surgical procedures. RESULTS: We observed 18 (12.5%) active air leaks, among which 4 (2.8%) were prolonged air leaks characterized by high differential pleural pressure due to increased mean expiratory pressure (>1 cm H(2)O; p<0.0001), and 3 (2.1%) late air leaks, all long-lasting (p<0.0001), predicted by pressure curve divergence before the air flow appearance. We also reported 25 (17.4%) pleural space effects characterized by a high differential pleural pressure, but mainly due to a lower mean inspiratory pressure (<20 cm H(2)O; p<0.0001), and especially related to surgical pleurodesis procedures (p<0.0003) and wide lung resections (p<0.0002); there was no increasing pneumothorax after provocative clamping. CONCLUSIONS: A digital chest drain system, ensuring continuous air flow and pleural pressure measurement, could clearly identify a pleural space effect, avoiding the frequent misinterpretation of an active air leak, and allowing safe removal of the chest tube at the right time.