Ineffectiveness of heparin treatment in burn shock in the guinea pig.

The cardiovascular and metabolic responses during burn shock were characterized in 10 guinea pigs burned to the xyphoid process for 3 s in boiling water. This produced a burn of approximately 70% of the body surface. Their responses were compared to the values obtained at corresponding times in a group of unburned controls (n=10). The effect of Heparin treatment on burn shock was evaluated in another group (n=8) of guinea pigs burned to the xyphoid process and injected subcutaneously with 50,000 U Heparin/kg immediately after being burned. In the burned, untreated (BUT) animals, cardiac output was reduced more than 50% at 15 mins post-burn, and cardiac output remained depressed for the next 8 h. Mean arterial blood pressure was initially maintained in the BUT animals, but started to fall after 3 h. Heart rate, oxygen consumption and core temperature all decreased progressively in the BUT group. Hemoconcentration was evident in the BUT animals, and there was an elevation in the post-burn glucose and lactate levels, a decrease in pH, and no change in free fatty acids. Heparin treatment did not significantly modify 24-h survival, and the post-burn cardiovascular responses of the Heparin-treated animals were similar to those of the BUT animals. Metabolically, the Heparin-treated animals had a significant elevation in free fatty acids post-burn, but otherwise closely resembled the BUT animals.