Dextran or polyethylene glycol added to curosurf for treatment of meconium lung injury in rats

BACKGROUND: In experimental lung injuries, improvement of lung function after treatment with surfactant/polymer mixtures may depend on both type of polymer and the specific surfactant. In vitro studies suggest that dextran is more effective when mixed with Curosurf, and polyethylene glycol (PEG) is more effective when mixed with Survanta. We therefore wanted to find out whether these results held true in an animal model of acute lung injury. OBJECTIVE: To compare the response to therapy of PEG vs. dextran when added to Curosurf after meconium lung injury. METHODS: Lung injury was produced by intratracheal instillation of meconium (30 and 4 ml/kg). One hour after injury, Curosurf (35 mg/ml) with or without 5% dextran (68 kDa) or 5% PEG (10 kDa) was given. Arterial blood gases and peak inspiratory pressures were measured for 3 h after treatment while animals were supported by volume-regulated ventilation. Then animals were sacrificed and pressure volume relationships, lung wet/dry weights, and histology were assessed. RESULTS: Initially, improved PaO2 and inspiratory pressure occurred for both Curosurf/PEG and Curosurf/dextran groups compared with Curosurf, but at three hours, peak inspiratory pressure and PaO2 remained significantly improved for the Curosurf/dextran but not for Curosurf/PEG groups when compared with Curosurf alone. Total lung capacity at the end of the experiment was also significantly increased in the Curosurf/dextran group, but not the Curosurf/PEG group when compared with Curosurf. CONCLUSION: Under these experimental conditions, Curosurf/dextran mixtures provided a better therapeutic response than Curosurf/PEG or Curosurf.