The nurse is providing care for a client who has syndrome of inappropriate antidiuretic hormone (SIADH) and is critically ill. Which of the following lab findings requires immediate intervention?

Serum calcium 8.0 mg/dl (Range of 8.8 to 10.4 mg/dL)

Serum potassium 5.0 mEq/L (Range of 3.5 to 5.0 mEq/L)

Blood urea nitrogen (BUN) 24 mg/dL (Range of 10 to 20 mg/dL).

Serum sodium 117 mEq/L (Range of 136 to 145 mEq/L)