Perfluorocarbon-associated gas exchange (partial liquid ventilation) in respiratory distress syndrome: A prospective, randomized, controlled study

Objective: To determine the efficacy of perfluorocarbon-associated gas exchange (partial liquid ventilation) in respiratory distress syndrome. Design: Prospective, randomized, controlled study. Setting: State University of New York at Buffalo, School of Medicine and Biomedical Sciences. Subjects: Eleven premature lambs with respiratory distress syndrome, delivered by cesarean section. Interventions: Five lambs were supported by conventional mechanical ventilation alone. Six lambs were switched to perfluorocarbon- associated gas exchange after 60 to 90 mins of conventional mechanical ventilation. Perfluorocarbon-associated gas exchange was accomplished by instilling a volume of liquid perfluorocarbon equivalent to normal functional residual capacity (30 mL/kg) into the trachea, performing 3 to 4 mins of tidal liquid ventilation, and, at end-expiration, with liquid functional residual capacity of 30 mL/kg remaining in the lung, reconnecting the animal to the volume ventilator for gas tidal volumes. Measurements and Main Results: Serial arterial blood gases and lung mechanics were measured. While receiving conventional ventilation, all animals developed progressive hypoxemia, hypercarbia, and acidosis. However, in the perfluorocarbon- associated gas exchange group, within 5 mins of the initiation of perfluorocarbon-associated gas exchange, mean PaO₂ increased four-fold, from 59 ± 6 torr (7.9 ± 0.8 kPa) during conventional ventilation to 250 ± 28 torr (33.3 ± 3.7 kPa; p < .05) during perfluorocarbon-associated gas exchange, and this increase was sustained at 60 mins of perfluorocarbon- associated gas exchange (268 ± 38 torr; 35.7 ± 5.1 kPa; p < .05). Mean PaCO₂ decreased progressively from 62 ± 4 torr (8.3 ± 0.5 kPa) during conventional ventilation to 38 ± 3.3 torr (5.1 ± 0.4 kPa) at 60 mins of perfluorocarbon-associated gas exchange (p < .05). Mean pH concomitantly increased. Dynamic compliance increased three-fold within 15 mins of instituting perfluorocarbon-associated gas exchange, from 0.31 ± 0.02 mL/cm H₂O during conventional ventilation to 0.90 ± 0.11 mL/cm H₂O during perfluorocarbon-associated gas exchange, and this increase was sustained at 60 mins of perfluorocarbon-associated gas exchange (p < .05). Mean peak expiratory flow and mean expiratory resistance were essentially unchanged during perfluorocarbon-associated gas exchange as compared with conventional ventilation in the same group. Conclusions: We conclude that perfluorocarbon- associated gas exchange, which employs liquid functional residual capacity and gas tidal volumes delivered by a conventional ventilator, can facilitate oxygenation and CO₂ removal, and dramatically improve lung mechanics in the premature lamb with respiratory distress syndrome.