Table 1. The independent role of differential pleural pressure and air-flow predicts the risk of prolonged air leak (PAL), defined as air leak longer than 7 days. Adapted from (22).

Differential pleural pressure & flow	Risk of PAL
ΔP ≤10 mmHg & flow ≤50 mL/min	4%
ΔP >10 mmHg & flow ≤50 mL/min	15%
ΔP ≤10 mmHg & flow >50 mL/min	36%
ΔP >10 mmHg & flow >50 mL/min	52%