EFFECT OF HYDROXYETHYL STARCH ON ALVEOLAR FLOODING IN ACUTE LUNG INJURY IN DOGS

The efficacy of hydroxyethyl starch (HES) in limiting alveolar floodin g after acute lung injury was investigated using ethchlorvynol (ECV)-i nduced low pressure pulmonary edema in dogs. Harvested autologous plas ma (PL) (control, n = 8) or 6% HES (n = 8) was infused (25 ml/kg) alon g with packed cells to result in an isovolemic, normochromic preparati on before the administration of ECV. Extravascular thermal volume sign ificantly increased after ECV administration in both groups of animals (6.6 to 13.4 ml/kg in PL, 6.5 to 15.0 ml/kg in HES). Systemic arteria l PO2 decreased from 216 +/- 4 to 113 +/- 20 mm Hg, and venous admixtu re increased from 2.8 to 12.8% in the PL group but was not significant ly changed in the HES group (219 +/- 5 to 203 +/- 8 mm Hg, and 2.9 to 4.4%, respectively). Epithelial lining fluid volumes after ECV adminis tration increased in both groups but were elevated in the PL group to a greater extent than in the HES group (13.5 ml in HES versus 24.8 ml in PL). In the HES group there appeared to be no difference in the abi lity of plasma proteins to move across the alveolar epithelium. These results suggest that HES attenuates the flooding of the alveolar space and the resulting alterations in gas exchange during the development of low pressure pulmonary edema. The replacement of the plasma protein s with HES and the apparent inability of HES to cross the epithelial b arrier into the alveoli may account for the protective effect of HES i n these experiments.