A 7-year-old girl is in the ICU with sepsis and is noted to have a serum sodium of 130 mEq/L, a low serum osmolality of 270 mOsm/kg, and a urine osmolality of 450 mOsm/kg. Her urine sodium is 50 mEq/L. She is clinically euvolemic. These findings are most consistent with?