How long do we need to give antioxidant therapy during resuscitation when its administration is delayed for two hours?

Twenty-four guinea pigs with third-degree burns over 70% of the body surface area were divided equally into four groups. All animals received Ringer's lactate (R/L) beginning 30 minutes after burn injury. Group 1 received R/L without vitamin C beginning 2 hours after burn injury. Groups 2, 3, and 4 received R/L with vitamin C until 4, 8, and 24 hours after burn injury, respectively. Beginning 3 1/2 hours after burn injury the hourly fluid volume was reduced to 25% of the Parkland formula calculation. The hourly sodium and fluid intake in each group was the same. Groups 1 and 2 demonstrated higher hematocrit and lower cardiac output values as compared with those values for group 3, indicating hypovolemia and hemoconcentration in these groups. Group 3 showed hematocrit and cardiac output values equivalent to those values for group 4. We conclude that high-dose vitamin C must be given until 8 hours after burn injury to maintain adequate hemodynamic stability in the presence of a reduced resuscitation fluid volume.