Fluid, electrolytes and protein are lost from the circulation at the site of the burn, and elsewhere in the body. There is also increased evaporative loss as a result of skin damage. Losses at the burn site are the result of increased capillary permeability, due both to direct injury and to production and release of mediators such as histamine, thromboxane and cytokines by the burn wound.
Fluid resuscitation of burn victims is therefore an important part of their management. Intravenous access is required when the burned area is >10% of body surface area. Protein losses are replaced by administering a 50:50 mixture of 5% albumin and 0.9% (normal) saline. A formula to calculate 24-hour fluid volume is:
Fluid (ml) = 3 x body weight (kg) x body surface area burned (%)
Half is given in the first 8 hours and the remainder in the next 16 hours.
This is in addition to maintenance fluids which are given as 0.45% saline + 5% dextrose.
Fluid administration is adjusted to maintain urine output at 0.75-1.0 ml/kg/hr.