The practical nurse (PN) reviews the laboratory results of an elderly female client who is one day postoperative for a right total hip replacement (THR). Which serum value result has the greatest implication for client safety? Reference ranges Hemoglobin (Hgb) [12 to 16 g/dL (120 to 160 g/L)] Potassium (K+) [3.5 to 5.0 mEq/L (3.5 to 5.0 mmol/L)] Sodium [136 to 145 mEq/L (136 to 145 mmol/L)] Blood Urea Nitrogen (BUN) [10 to 20 mg/dL (3.6 to 7.1 mmol/L)]