Question

An $82$-year-old woman residing in an assisted living facility is brought to the emergency center after developing bilious emesis and progressive abdominal bloating over the past two days. Her medical history includes an open cholecystectomy and atrial fibrillation. For the last $12\text{ hours}$, her previously colicky cramping has transitioned into a constant, severe ache. Her temperature is $38.1^\circ\text{C}$ ($100.6^\circ\text{F}$), blood pressure is $102/60\text{ mm Hg}$, and pulse is $115/\text{min}$ and irregularly irregular. Physical evaluation shows marked abdominal distension. Bowel sounds are absent. Light palpation produces significant guarding and rigidity localized to the periumbilical region. Laboratory values show a leukocyte count of $16,500/\text{mm}^3$ with $12\%$ bands, a hemoglobin of $13.2\text{ g/dL}$, and a venous lactate of $4.2\text{ mmol/L}$. An acute abdominal series reveals dilated central bowel loops, prominent mucosal folds extending entirely across the lumen, and multiple air-fluid levels. There is no free intraperitoneal air. Which of the following is the most appropriate management for this patient's current condition?