Effect of hydroxyethyl starch on alveolar flooding in acute lung injury in dogs.

The efficacy of hydroxyethyl starch (HES) in limiting alveolar flooding after acute lung injury was investigated using ethchlorvynol (ECV)-induced low pressure pulmonary edema in dogs. Harvested autologous plasma (PL) (control, n = 8) or 6% HES (n = 8) was infused (25 ml/kg) along with packed cells to result in an isovolemic, normochromic preparation before the administration of ECV. Extravascular thermal volume significantly 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 arterial PO2 decreased from 216 +/- 4 to 113 +/- 20 mm Hg, and venous admixture increased from 2.8 to 12.8% in the PL group but was not significantly 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 administration 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 ability 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 proteins with HES and the apparent inability of HES to cross the epithelial barrier into the alveoli may account for the protective effect of HES in these experiments.