Experimentally-induced acute lung injury: the protective effect of hydroxyethyl starch

The objective of this study was to evaluate the effects of hydroxyethyl starch, (130/0.4) 6%, compared to Ringer's acetate and modified gelatin on hypoxemia, inflammatory response, and oxidative stress in an experimental model of acute lung injury (ALI). The ALI/Adult Respiratory Distress Syndrome (ARDS) experimental model was produced by a bronchoalveolar saline lavage. Mature New Zealand white rabbits were anesthetized, provided with a tracheostomy and vascular catheters, and randomized to receive 25 ml/kg/hr of Ringer's acetate (group R, n = 7), 25 ml/kg/hr of modified gelatin (group G, n = 7), or 25 ml/kg/hr of hydroxyethyl starch (group S, n = 7). All of the rabbits received mechanical ventilation to maintain the PaCO2 between 35 and 45 mm Hg. Blood gas levels and hemodynamic values were recorded before induction of lung injury (T0) and 10 (T10), 120 (T120) and 240 (T240) min following induction of lung injury. At the same time-points, blood samples were collected to measure the plasma levels of TNFalpha (tumor necrosis factor-alpha) and TBARS (thiobarbituric acid-reactive substances). The experiment yielded the following results: The blood PaO2/FiO2 ratio was higher in group S than in groups R and G at T10, T120, and T240 (p <0.05). In group S, the plasma TNFalpha and TBARS concentrations were lower than in groups R and G at T120 and T240 (p <0.05). In conclusion, rabbits treated with hydroxyethyl starch, (130/0.4) 6%, demonstrated reductions of hypoxemia, inflammatory response, and oxidative lung damage, compared to raabbits treated with Ringer's acetate or modified gelatin.