Question

Paramedics bring a $54$-year-old woman to the emergency department due to acute, unremitting abdominal pain and persistent bilious vomiting that began $8$ hours ago. Her medical history is notable for a total abdominal hysterectomy for uterine fibroids performed $4$ weeks ago. She reports that the pain initially started as intermittent cramps but rapidly progressed to become constant and excruciating over the last $2$ hours. Her temperature is $38.6^\circ\text{C}$ ($101.5^\circ\text{F}$), blood pressure is $86/52\text{ mm Hg}$, pulse is $128/\text{min}$, and respirations are $24/\text{min}$. The patient appears diaphoretic, toxic, and lies completely still on the gurney. Physical examination reveals a markedly distended abdomen with involuntary guarding, board-like rigidity, and severe rebound tenderness in all four quadrants. Auscultation yields absent bowel sounds. Laboratory analysis demonstrates a leukocyte count of $21,500/\text{mm}^3$ and a serum lactate level of $5.2\text{ mmol/L}$. An upright abdominal radiograph displays multiple dilated loops of small intestine with prominent air-fluid levels and an absence of colonic gas. Which of the following is the most appropriate next step in the management of this patient?