Pulmonary hypertension and microvascular injury in rats given parenteral nutrition.

Clinical reports have suggested that parenteral nutrition may damage the lungs. We studied the pathophysiologic pulmonary changes in rats receiving a fat emulsion (Intralipid), an amino acid solution (Vamin-glucose) or saline solution. Control rats were not infused. The pulmonary arterial pressure, capillary filtration coefficient and inactivation of serotonin were determined in isolated, perfused lungs following the in vivo perfusion with the respective solutions. After 12 days of Intralipid infusion the rats showed pulmonary hypertension, increased capillary filtration coefficient and reduced inactivation of serotonin compared with control lungs. Reduction of serotonin inactivation was found after only 3 days. Vamin-glucose infusion altered only serotonin clearance. Saline infusion did not change lung function compared with controls. The study suggests that parenteral nutrition in rats may lead to severe and possibly lethal pulmonary changes.