Partial liquid ventilation influences pulmonary histopathology in an animal model of acute lung injury

Purpose: The aim of this study was to assess the effect of partial liquid ventilation (PLV) and conventional mechanical ventilation (CMV) in the pattern of distribution of lung injury in a rabbit model of acute lung injury. Materials and Methods: Animals (1.5 to 3.5 kg) were assigned to receive CMV (tidal volume of 10 mL/kg and a PEEP of 5 cm H₂O) or PLV with 18 mL/kg of intratracheal perflubron (tidal volume of 10 mL/kg and a PEEP of 5 cm H₂O). Lung injury was elicited by intravenous administration of Escherichia coli endotoxin. Uninjured animals ventilated as the CMV group served as controls. After 4 hours of mechanical ventilation, the lungs were removed and tissue injury was assessed by light microscopy using a scoring system. Results: Animals in the CMV group had higher lung injury scores in comparison to the PLV group (10 ± 4.5 vs. 5 ± 3.3, respectively, P < .05). The injury scores were similar for nondependent lung regions (CMV: 8 ± 4.3, PLV: 6 ± 2.9) but significantly different for the dependent regions (CMV: 12 ± 4.6, PLV: 5 ± 3.8, P < .05). Conclusions: PLV is associated with significant attenuation of lung injury, in comparison to CMV. This effect is predominantly due to attenuation of injury in the dependent region of the lung.