The healthcare provider prescribes a 5% dextrose injection with 20 units of regular insulin for a client with a serum potassium level of 6.0 mEq/L (6.0 mmol/L) and glucose level of 180 mg/dL (10.0 mmol/L). Which evaluation is most important for the nurse to include in this client's plan of care? Reference Range: Potassium [3.5 to 5.0 mEq/L (3.5 to 5.0 mmol/L)] Glucose [74 to 106 mg/dL (4.1 to 5.9 mmol/L)]