Q. A 45-year-old man presents to the emergency department with a 6-hour history of sharp, cramping pain in the right upper quadrant of his abdomen that radiates to his right shoulder. He describes the pain as waxing and waning in nature. He reports having similar but milder episodes over the past year, often after a heavy meal. He also mentions experiencing some episodes of nausea and bloating. His medical history is notable for obesity and hyperlipidemia, for which he takes atorvastatin. On physical examination, the patient appears uncomfortable, with a noticeable grimace on his face. Vital signs include a blood pressure of 140/90 mmHg, pulse rate of 105 bpm, respiratory rate of 16 breaths per minute, temperature of 98.4°F (36.9°C), and oxygen saturation of 99% on room air. His BMI is 31 kg/m^2. On abdominal examination, there is tenderness in the right upper quadrant and a positive Murphy's sign. Laboratory findings include a white blood cell count of 10,000/?L, total bilirubin of 1.0 mg/dL, direct bilirubin of 0.4 mg/dL, and liver enzymes within normal limits. An abdomen ultrasound reveals multiple echogenic foci in the gallbladder, with acoustic shadowing suggesting gallstones. What is the most appropriate next step in management?