Perfluorocarbon-associated gas exchange

Background and Methods: Liquid ventilation with oxygenated perfluorocarbon eliminates surface tension due to pulmonary air/fluid interfaces, and improves pulmonary function and gas exchange in surfactant deficiency. In liquid ventilation, perfluorocarbon is oxygenated, purged of CO₂, and cycled into and out of the lungs using an investigational device. A new approach, perfluorocarbon-associated gas exchange, uses a conventional ventilator and combines features of liquid ventilation and continuous positive-pressure breathing. In 13 normal piglets, a volume of perfluorocarbon equivalent to the normal functional residual capacity (30 mL/kg) was instilled into the trachea, left in situ, and volume-regulated gas ventilation (FIO₂ 1.0) was resumed. For 1 hr, perfluorocarbon was continuously bubble-oxygenated within the lungs, where it directly participated in gas exchange. Results: PaO₂ and PaCO₂ averaged 401 ± 51 and 40 ± 4 torr (53.6 ± 6.8 and 5.3 ± 0.5 kPa), respectively. Peak airway pressure during perfluorocarbon-associated gas exchange (22 ± 2 cm H₂O at 1 hr) and during continuous, positive-pressure breathing (23 ± 4 cm H₂O) were nearly identical. Venous oxygen saturation and pH were normal (73 ± 8% and 7.43 ± 0.05, respectively, at 1 hr). Conclusions: Perfluorocarbon-associated gas exchange was uniformly well tolerated, and its efficiency approached that of continuous positive-pressure breathing. Applications of perfluorocarbon technology to lung disease may not be limited by existing instrumentation.