An estimate of the percent of body surface burned is used to determine if fluid replacement (intravenous infusion) is needed to prevent or help control shock and, if so, the amount of fluid to be administered.

The amount of body surface burned can be estimated using the “rule of nines.” The approximate skin surface of each section of an adult body is shown in figure 6-3.

a. When estimating the amount of skin surface burned to determine the amount of intravenous fluids to be administered, only count the areas covered by second-degree and/or third-degree burns.

b. If the casualty is a small child, the percentages change slightly. Figure 6-4 gives the approximate body surface area (BSA) percentages for a small child.