A comparison of demand-valve and bag-valve ventilations in a swine pneumothorax model

Objective: Two means of delivering artificial ventilation readily available 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. This study compared the changes in size of pneumothorax in swine ventilated with the 2 devices. Methods: Three swine were anesthetized, intubated, and instrumented with a femoral arterial line and a pediatric Swan-Ganz catheter. A chest tube was placed, the chest was opened, and the lung parenchyma was visualized. The lung was disrupted by a single stab 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 animals were ventilated by 12 emergency medical technicians using either BV or OPDV. After 10 minutes of ventilation, the pneumothorax volume was measured. Results: When comparing final pneumothorax volumes after 10 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.