Question

An ambulance brings a 31-year-old female to the resuscitation bay following the sudden onset of excruciating, diffuse abdominal pain that began two hours prior to arrival. Over the preceding five days, she had experienced progressive lower pelvic discomfort, high fevers, and a foul-smelling vaginal discharge. Her temperature is $39.4^\circ\text{C}$ ($102.9^\circ\text{F}$), blood pressure is $80/45\text{ mm Hg}$, and pulse is $132/\text{min}$. She appears lethargic and is profoundly diaphoretic. Following the rapid intravenous infusion of $2\text{ L}$ of normal saline, her blood pressure remains $84/48\text{ mm Hg}$. Physical examination reveals a rigid, board-like abdomen with severe diffuse tenderness, involuntary guarding, and rebound. Pelvic examination is limited by extreme pain but shows purulent exudate pooling at the cervical os. A bedside transvaginal ultrasound demonstrates a $7\text{-cm}$ complex, multiloculated right adnexal structure with a disrupted capsular margin, accompanied by a large volume of echogenic free fluid in the pelvis and right upper quadrant. Which of the following is the most appropriate next step in the management of this patient?