Table 1.

Cerfolio Classification of Air Leaks

Grade 1, FE	During forced expiration only, typically when asking the patient to cough
Grade 2, E	Expiratory only
Grade 3, I	Inspiratory only
Grade 4, C	Continuous bubbling present in the air leak chamber during both inspiration and expiration. These leaks tend to be large and are more likely to be seen in patients receiving positive-pressure ventilation.