A nurse is assessing a client for fluid volume deficit following lumbar spinal surgery. The nurse should identify which of the following findings as an indication the client is at risk for fluid volume deficit?

Rationale: A. BUN 16 mg/dL (10 to 20 mg/dL): This is a normal blood urea nitrogen level and does not indicate dehydration or fluid volume deficit. Elevated BUN may suggest volume depletion, but this value is within the expected range. B. Urine output 40 mL every hour for 3 hr: A urine output of 30 mL/hr or greater is considered adequate in most adult clients. Therefore, 40 mL/hr is within acceptable limits and does not suggest fluid volume deficit. C. Hct 42% (37% to 47%): This hematocrit level falls within the normal range and does not indicate hemoconcentration. Elevated hematocrit could signal dehydration, but this value alone does not support that conclusion. D. Surgical drain output 300 mL during an 8-hr shift: This is a significant amount of fluid loss postoperatively and can contribute to fluid volume deficit. High drain output following surgery, especially spinal procedures, increases the client's risk for hypovolemia and should be closely monitored.