A 78-year-old woman with a history of atrial fibrillation and a recent lapse in her anticoagulant medication presents to the emergency department with a 2-hour history of severe, acute-onset generalized abdominal pain. She reports nausea and one episode of vomiting. Her temperature is 37.2°C (99.0°F), pulse is 118/min and irregular, blood pressure is 138/86 mm Hg, and respirations are 20/min. Physical examination reveals a soft abdomen with minimal tenderness to palpation, which is strikingly disproportionate to the severity of her reported pain. Laboratory studies show a leukocyte count of 18,000/mm³ and a significantly elevated serum lactate level. Arrange the following management steps in the most appropriate sequential order for this patient.
- 1Initiate aggressive intravenous fluid resuscitation and provide adequate analgesia.
- 2Obtain a multiphasic CT angiography of the abdomen and pelvis.
- 3Administer systemic intravenous anticoagulation and broad-spectrum antibiotics.
- 4Proceed to the operating room for exploratory laparotomy and possible bowel resection.
- 5Perform a second-look laparotomy 24 to 48 hours later to re-evaluate bowel viability.