Two hours before a client's scheduled surgery, the nurse is completing the preoperative checklist. Which information requires immediate action by the nurse? Reference Range: Potassium (3.5 to 5 mEq/L (3.5 to 5 mmol/L)]

A. Preoperative chest x-ray report is not available: While a chest x-ray may provide useful baseline information, the absence of this report is not immediately life-threatening. The surgery could still proceed safely if the client is otherwise stable. B. Preoperative serum potassium level is 2.8 mEq/L (2.8 mmol/L): A potassium level below the normal range places the client at high risk for life-threatening cardiac arrhythmias under anesthesia. This requires immediate correction before proceeding with surgery. C. Surgical consent form is not signed: A missing consent form is legally significant and must be addressed before surgery, but it does not pose an immediate physiological threat to the client. It can be corrected once the provider discusses the procedure with the client. D. Client's pulse oximeter reading is 96%: An oxygen saturation of 96% is within the acceptable range and does not indicate acute hypoxemia. While it should be monitored, this value does not represent an urgent or life-threatening concern.