A 76-year-old woman presents with a history of CHF to the hospital with abdominal pain of 24 hours’ duration and bloody diarrhea. Her temperature is 98.6°F (37.0°C), heart rate 90 beats/min, white blood cell count 16,000/mL (16´10⁹/L), and blood pressure 110/70 mm Hg. Computed tomography imaging is ordered (Figure); Her abdomen is tender but without peritoneal signs. Colonoscopy shows patchy, superficial areas of ulceration and sloughing in the transverse colon. The best next treatment for this patient is which of the following?

CT Scan