Effects of partial liquid ventilation on regional pulmonary blood flow distribution of isolated rabbit lungs

Objective: Partial liquid ventilation with perfluorocarbons may increase al veolar hydrostatic transmural pressure and may result in a redistribution o f pulmonary blood flow from dependent to nondependent lung regions. To test this hypothesis under controlled study conditions, we determined intrapulm onary blood flow distributions during gas and perfluorocarbon ventilation i n isolated rabbit lungs. Design: Controlled animal study with an ex vivo isolated lung preparation. Setting. Research laboratory for Experimental Anesthesiology at the Heinric h-Heine-University of Dusseldorf, Subjects: New Zealand White rabbits. Interventions: The lungs were perfused with autologous blood at constant fl ow (150 mL/min) and ventilated with 5% Co, in air (positive end-expiratory pressure, 2 cm H2O; tidal volume, 10 mL/kg body weight; respiratory rate, 3 0 breaths/min) without and with perfluorocarbon administered intratracheall y (15 mL/kg), Measurements and Main Results: Regional lung perfusion was measured with co lored microspheres in apical, central, peripheral, and basal samples before and after bronchial instillation of perfluorocarbons. Compared with gas ve ntilation, intrapulmonary blood flow during perfluorocarbon ventilation was higher in apical samples (49.4 +/- 8.6 mL/min/g vs, 38.3 +/- 6.8 mL/min/g dry weight; p = .03) and lower in basal samples (22.2 +/- 5.1 mL/min/g vs. 39.9 +/- 8.2 mL/min/g; p = .04). Conclusions: Our findings suggest that during partial liquid ventilation, i ntrapulmonary blood flow is redistributed toward less-dependent lung region s.