A COMPARISON OF DEMAND-VALVE AND BAG-VALVE VENTILATIONS IN A SWINE PNEUMOTHORAX MODEL

Objective: Two means of delivering artificial ventilation readily avai lable to out-of-hospital personnel are the bag-valve (BV) and the O-2- powered demand-valve (OPDV). However, use of the OPDV has been limited because of concerns that it may worsen an underlying pneumothorax. Th is study compared the changes in size of pneumothorax in swine ventila ted with the 2 devices. Methods: Three swine were anesthetized, intuba ted, and instrumented with a femoral arterial line and a pediatric Swa n-Ganz catheter. A chest tube was placed, the chest was opened, and th e lung parenchyma was visualized. The lung was disrupted by a single s tab with a #10 scalpel; the chest was then sealed; and a pneumothorax was created by injecting 30 mL of air through the chest tube. The anim als were ventilated by 12 emergency medical technicians using either B V or OPDV. After 10 minutes of ventilation, the pneumothorax volume wa s measured. Results: When comparing final pneumothorax volumes after 1 0 minutes of ventilation with the 2 devices, there was no significant difference (mean +/- SD = 40.8 +/- 28.2 mL vs 52.3 +/- 23.1 mL, p = 0. 286). Conclusion: There is no difference in final pneumothorax volumes after OPDV or BV ventilation.