Hemodynamic effects of delayed initiation of antioxidant therapy (beginning two hours after burn) in extensive third-degree burns.

The hemodynamic effects of the delayed initiation of antioxidant therapy with high-dose vitamin C were studied in 12 guinea pigs with third-degree burns over 70% of their body surface area. All animals were resuscitated with Ringer's lactate solution (RL) according to the Parkland formula (4 ml/kg/% burn during the first 24 hours) from 1/2 to 2 hours after burn, and the infusion rate was reduced thereafter to 25% of that of the Parkland formula. The vitamin C group (n = 6) received RL with vitamin C (14 mg/kg/hr), and the control group (n = 6) received RL only. The 24-hour fluid intake for each group was 32.5% of the Parkland formula volume. Burn wound edema in the vitamin C group was significantly less than that in the control group. The vitamin C group maintained adequate hemodynamic stability as determined with hematocrit and cardiac output values, but the control group did not. Even though the initiation of the vitamin C administration is delayed until 2 hours after burn, the hourly infusion rate of the resuscitation fluid can be reduced to 25% once it is started. Thus antioxidant therapy with adjuvant vitamin C administration may be applicable to the clinical setting in which a patient with burns arrives at the burn care facility a few hours after the burn injury occurred.