The patient with toxic epidermal necrolysis (TEN) is at risk for fluid and electrolyte imbalance related to insensible loss through large areas of open wounds. The best parameters to assess in the patient with TEN are urine output and central venous pressure because these show the fluid available to the vasculature. Low central venous pressure and low urine output are treated with increased IV fluid rates. TEN is associated with significant epidermal edema; therefore, weight, skin turgor, and limb circumference do not provide an adequate assessment of the patient’s hydration status. Serum sodium, rather than potassium, can be used to assess fluid status.