Bronchoscopic surfactant administration preserves gas exchange and pulmonary compliance after single lung transplantation in dogs

AbstractBackgroundSurfactant abnormalities have been implicated in reperfusion injury and respiratory failure in lung transplantation.MethodsWe investigated the efficacy of bronchoscopic administration of a bovine natural lung surfactant extract (Alveofact) to improve gas exchange and lung mechanics after heterologous left lung transplantation in foxhounds (+4°C ischemia for 24 hours, conservation with Euro-Collins solution). Animals received either no surfactant therapy (untreated controls, n = 6) or 50 mg/kg body weight (prior to explantation, only graft) and 200 mg/kg body weight Alveofact (immediately after reperfusion, both lungs, n = 6). After lung transplantation, separate but synchronized ventilation of each lung was performed in a volume-controlled, pressure-limited mode for 12 hours, with the animals prone. Small catheters were inserted into the pulmonary veins of both the graft and the recipient's native lung for separate blood gas analysis. In the control group, marked protein leakage, influx of neutrophils into the alveolar space, and pulmonary edema formation (extravascular lung water; wet/dry ratio) were encountered in the transplanted lung but only to a very minor extent in the recipient's native lung.ResultsLung compliance values and arterial oxygenation progressively deteriorated in the transplanted but not in the native lungs. Pulmonary hemodynamics did not change significantly. Surfactant administration did not significantly influence the development of reperfusion edema, protein leakage, and neutrophil influx into the grafts. However, surfactant restored the surface activity and the gas exchange (Pao2/Fio2 of 201.2 ± 20.2 mm Hg vs 119.8 ± 21.7 mm Hg in controls; P < .05) in the transplanted lungs, and compliance was markedly improved in the surfactant-treated animals (18.8 ± 1.8 mL/mbar vs 11.5 ± 1.6 mL/mbar in the controls; P < .05).ConclusionBronchoscopic surfactant administration does not prevent leukocyte influx or vascular leakage but does protect against respiratory failure and improves lung mechanics in single lung transplantation in dogs