RESUMO
OBJECTIVE: To evaluate the effects of 24 h partial liquid ventilation (PLV) with and without surfactant (S) treatment on gas exchange and lung injury in a newborn animal model of S deficiency. DESIGN: A prospective, controlled, in vivo animal laboratory study. SETTING: Research laboratory in a university setting. SUBJECTS: Twenty-four pathogen-free, male piglets (mean weight 1.9 kg, age 1-3 days). INTERVENTIONS: The animals were randomised in four groups: PLV with FC-77 combined with conventional ventilation (PLV/CV) versus S + PLV/CV and PLV combined with high frequency oscillatory ventilation (PLV/HFOV) versus S + PLV/HFOV. The piglets were anaesthetised, intubated and instrumented with vascular catheters. Thirty minutes after lung injury had been induced with repeated saline lavage, S animals received natural S. Thirty minutes after surfactant substitution PLV with FC-77 was started. The oxygenation index (OI), PaO(2)/FIO(2) ratio, PaCO(2) and the ventilatory efficacy index were determined before and during PLV. After 24 h the lungs were removed for histopathological examination. MEASUREMENTS AND MAIN RESULTS: Within 60 min after the initiation of PLV, all animals demonstrated improvements of the OI and PaO(2)/FIO(2) ratio compared to the values after lung injury. However, at 18 and 24 h of PLV, the OI and PaO(2)/FIO(2) ratio were significantly worse in the S + PLV/CV and S + PLV/HFOV groups compared to the groups without S. PaCO(2) was higher at 18 and 24 h when S was used in PLV/HFOV (p < 0.05). A semi-quantitative lung injury score revealed most severe lung damage in the S + PLV/HFOV group. CONCLUSIONS++: The combination of S and PLV with FC-77 led to an impaired gas exchange and did not further protect the animal from lung injury.
