A nurse is caring for a client who is experiencing anxiety as well as numbness and tingling of the lips and fingers. The client's ABGS are: pH 7.48 (7.35 to 7.45), PaCO2 30 mm Hg (35 to 45 mm Hg), HCO3 24 mEq/L (21 to 28 mEq/L), PaO2 85 mm Hg (80 to 100 mm Hg). Which of the following acid- base imbalances should the nurse identify that the client is experiencing?