Conventional versus high frequency jet ventilation with a bronchopleural fistula

A bronchopleural fistula (BPF) is an aberrant pathway through which inspired gas exits the lungs. A BPF may cause significant respiratory compromise, which in turn may result in the need of mechanical ventilation. The purpose of this study was to compare the efficacy of conventional positive pressure ventilation (CV) with high frequency jet ventilation (HFJV) using increasing increments of positive end expiratory pressure (PEEP) in the management of an induced BPF. A reproducible model of a BPF was surgically created in 10 mongrel dogs. Measurements of blood pressure (BP), cardiac output (CO), mean airway pressure (Maw), peak airway pressure (Paw), and fistula flow (FF) were carried out with the chest closed. Selective occlusion of the BPF allowed for blood gas stabilization at increased values of PEEP. Paired observations were performed at 0, 5, 10, 15, and 20 cm H2O of PEEP, while maintaining PaCO2 between 30 and 50 Torr. There was no difference in BP or CO between ventilation methods even though significantly lower Maw and Paw pressures were obtained using HFJV. While FF increased significantly with each increment of PEEP, there was no improvement in flows obtained using HFJV. This acute model of a BPF demonstrated that increasing PEEP dramatically increases FF irrespective of the method of ventilation.