Prior to surgery, which data is most important to communicate to the health care provider because electrolyte imbalance can increase intraoperative risk?

• A. Pulse rate 59
• B. Hematocrit 35%
• C. Blood pressure 142/78
• D. Serum potassium 3.3 mEq/L

Answer: (D)

Potassium balance directly affects cardiac excitability and rhythm, so preoperative planning focuses on correcting electrolyte disturbances to lower the risk of intraoperative arrhythmias. A potassium level of 3.3 mEq/L is below normal, indicating hypokalemia. Hypokalemia can slow conduction and prolong repolarization, increasing the likelihood of dangerous arrhythmias during anesthesia and surgery. The perioperative environment—drugs, shifts in fluids, and stress—can worsen this imbalance, making it critical to address before proceeding. Other data like pulse rate, hematocrit, or blood pressure inform overall status but do not carry the same immediate, specific risk related to electrolyte-induced arrhythmias. Recognizing and correcting low potassium before surgery helps minimize intraoperative cardiac risk.