Evaluation of hyperdynamic resuscitation in 60% TBSA burn-injured sheep.

It has been suggested that hyperdynamic (HD) resuscitation improves outcomes. We hypothesized that initial HD resuscitation of burn injury using fluid and inotropes would improve metabolic function as indicated by base excess. We used an anesthetized ovine model of 60% TBSA full-thickness flame burn with delayed resuscitation started at 90 min after burn and continued for 8 h. Three groups (n = 6 each) were included: 1) HD defined as cardiac index (CI) of 1.5x baseline achieved by using Ringer's lactate alone (HD-Fluid); 2) Ringer's lactate and dobutamine (HD-Drug); and 3) Parkland Formula (Parkland) as a control group. Statistical analysis performed using analysis of variance and Tukey's HSD test. Significance accepted at P < 0.05. Higher CI was achieved in both HD-Fluid and HD-Drug groups, e.g., at 8 h the CI was 4.6 +/- 0.4 and 4.7 +/- 0.6 L/min/m respectively, as compared with Parkland 3.6 +/- 0.5 L/min/m. The net fluid balance (fluid infused - urine output) was similar in both Parkland and HD-Drug groups, which were 2.5x more in HD-Fluid (P = 0.001). The mean postburn urinary outputs were similar in both Parkland and HD-Drug groups, e.g., Parkland (0.9 +/- 0.08 mL/kg/h), HD-Drug (1.0 +/- 0.2 mL/kg/h) and increased in HD-Fluid (3.7 +/- 1.0 mL/kg/h; P = 0.0005). Base excess remained positive in both HD-Drug (+2.5 +/- 1 mmol/L) and Parkland (+1.5 +/- 1.7 mmol/L), and declined to -4.0 +/- 3.6 mmol/L in HD-Fluid group (P = 0.036). We conclude that there may be no benefit to using hyperdynamic regimens for the initial resuscitation of burn injury.