PATHOGENESIS AND TREATMENT OF THE ADULT-RESPIRATORY-DISTRESS-SYNDROME

The adult respiratory distress syndrome is an acute clinical illness c haracterized by noncardiogenic pulmonary edema and refractory hypoxemi a. Injury to the alveolar-capillary barrier and lung inflammation lead to intrapulmonary shunting of blood, surfactant depletion, and pulmon ary vascular obstruction, Numerous mediators contribute to the patholo gic response, Conventional therapy includes treating underlying causes and positive pressure mechanical ventilation. Concern about pressure- induced lung injury had led to new strategies to accomplish adequate g as exchange. Novel therapeutic interventions have included extracorpor eal support techniques, use of compounds designed to neutralize proinf lammatory cytokines, and administration of surfactants, but these effo rts have not definitely affected mortality in randomized trials. Poten t antioxidant agents have shown promise in animal models of acute lung injury, but human studies are lacking. Inhaled nitric oxide appears t o have temporary effects on pulmonary artery pressure and on ventilati on or perfusion relationships, but longer-term efficacy and safety in patients suffering from adult respiratory distress syndrome is unknown and awaits results of ongoing clinical trials.