A 45-year-old male patient presents to the emergency department with sudden-onset, severe abdominal pain that started 6 hours ago. He has a rigid abdomen and is guarding. His vital signs are blood pressure 100/60 mmHg, heart rate 120 bpm, respiratory rate 22 breaths/min, and temperature 38.2°C. What is the BEST immediate next step in the management of this patient?
Initiate aggressive fluid resuscitation and consult a surgeon.
Administer broad-spectrum antibiotics immediately.
Apply a heating pad to the abdomen to provide symptomatic relief.
Order abdominal x-rays and laboratory studies.