Abstract

We performed an experimental trial comparing crystalloid (Ringer's lactate) and colloid (hetastarch) resuscitation in pentobarbital-anesthetized pigs. Superior mesenteric arterial blood flow (Qsma) was measured using an ultrasonic flow probe, and ileal intramucosal hydrogen ion concentration [( H+]I) was estimated tonometrically. Beginning at t = 0 min, all animals were infused over 20 min with Escherichia coli (0111:B4) lipopolysaccharide (LPS; 150 micrograms/kg). Starting at t = 0 min and continuing for the duration of the experiment (3 hr), pigs in group I (N = 9) were resuscitated with Ringer's lactate (1.2 ml/kg min), whereas animals in group II (n = 9) were infused with 6% hetastarch in saline (0.4 ml/kg min). Systemic and mesenteric hemodynamic changes induced by LPS were similar in both groups; mean arterial pressure and systemic vascular resistance index decreased (P less than .05), but cardiac index was well preserved. Central venous pressure increased (P less than .05). Superior mesenteric O2 delivery decreased significantly (P less than .05) in both groups, although mesenteric O2 uptake was unchanged. Ileal [H+]I increased (P less than .05) in both groups. Gravimetrically determined extravascular water was greater in lung (P = .03) and ileum (P = .058) in group I as compared to group II. Although crystalloid infusion was associated with greater tissue edema, this effect did not translate into a difference in systemic or regional (i.e., mesenteric) O2 uptake or greater ileal tissue acidosis.