The nurse is analyzing the diagnostic results of a female patient who has nausea, vomiting, and was admitted for an exacerbation of ulcerative colitis with bloody, purulent stool (See the table below). Which of the following orders does the nurse implement first? Diagnostic Test Result Reference Range Serum White Blood Cell (WBC) count 18.500/mm3 4,500-10,000/mm3 Serum Potassium 3.4 mEq/L 3.5-5.0 mEq/L Serum Sodium 136 mEq/L 135-145 mEq/L

A. Administer metronidazole 500 mg IV over 1 hour: Metronidazole treats infection or colitis-associated bacterial overgrowth, which is important, but it does not immediately correct the patient’s electrolyte imbalance or prevent cardiac complications from hypokalemia. B. Administer potassium chloride 40 mEq PO: The patient’s potassium is 3.4 mEq/L, below the normal range. Hypokalemia increases the risk for life-threatening cardiac arrhythmias, especially in patients with ongoing fluid loss from diarrhea and vomiting. Correcting potassium promptly takes priority to stabilize cardiac and neuromuscular function. C. Administer ondansetron 4 mg IV over 2 minutes: Ondansetron can reduce nausea and vomiting and help prevent further fluid and electrolyte loss, but it does not immediately correct the existing hypokalemia. Symptom control is important but secondary to addressing potentially dangerous electrolyte disturbances. D. Administer 4 oz of oral fluids for hydration: Oral hydration is helpful for mild fluid loss, but the patient’s ongoing diarrhea and vomiting may limit absorption. Immediate potassium replacement is more critical to prevent cardiac complications, and IV or PO potassium should be prioritized alongside hydration strategies.