Respiratory gas exchange and inert gas retention during partial liquid ventilation

Perfluorocarbon (PFC) fluids have been used as ventilatory media due to their unique combination of low toxicity, low solubility in body fluids, ability to lower interfacial tensions, and high oxygen and carbon dioxide carrying capacities12. Cardiorespiratory support has been achieved during liquid ventilation with a variety of perfluorinated chemicals in a range of experimental animals1,2,7,8,9,18. In animal models of respiratory distress syndrome, introduction of PFC to the lungs has been shown to improve both compliance and gas exchange11,13,14,15,16 However, the presence of fluid in the gas exchange regions of the lung should impede convective and diffusive mass transport and have a deleterious effect on gas exchange. Indeed, while it is possible to achieve adequate oxygenation during liquid ventilation, CO2 retention and acidosis can be problematic7. In order to maximize the benefits of this mode of ventilation while minimizing the side effects of CO2 retention, acidosis, and O2 toxicity due to high FIO2, a clearer understanding of the determinants of gas exchange through a fluorocarbon medium is necessary.