Comparison of effects of dextran-70 and Ringerʼs acetate on pulmonary function, hemodynamics, and survival in experimental septic shock

Abstract

The effects of dextran-70 with NaCl vs. Ringer's acetate on hemodynamics, gas exchange, oxygen transport, and survival were evaluated in a porcine model of pulmonary and circulatory insufficiency induced by a continuous iv endotoxin infusion over 6 h. Dextran and Ringer's acetate were infused continuously to maintain baseline mean left atrial pressure (LAP) throughout the endotoxin period. Twelve pigs receiving endotoxin + Ringer's acetate displayed a progressive 45% decline in cardiac output (Qt) and a two-peaked increase in pulmonary vascular resistance (PVR) with a late increase of 250%. Venous admixture (Qva/Qt) increased progressively more than six-fold and extravascular lung water (EVLW) increased by 55%. Mean arterial BP (MAP) fell by 25%, oxygen delivery by 40%, base excess (BE) ranged between -4.5 and -9 mmol/L at the end of the endotoxin period and four of 12 animals died. Polymorphonuclear cell count (PMN) fell rapidly by 90% and was decreased severely throughout the endotoxin period. By contrast, the 12 pigs that received endotoxin + dextran maintained Qt near baseline and PVR was significantly lower in this group. Qva/Qt increased progressively more than four-fold, but it was significantly lower than in the Ringer's acetate group as was the increase in EVLW (23%). MAP only decreased by 10%, oxygen delivery only decreased by 20%. BE ranged between -1.0 and -3.0 mmol/L at the end of the endotoxin period and all animals survived. PMN fell by 90% at 0.5 h but subsequently tended to return toward baseline, and PMN were significantly increased compared with the Ringer's acetate group.(ABSTRACT TRUNCATED AT 250 WORDS)