Review Question - QID 213215

A 27-year-old man presents to the emergency department for altered mental status. The patient was found napping in a local market and brought to the hospital. The patient has a past medical history of polysubstance abuse and is homeless. His temperature is 104°F (40.0°C), blood pressure is 100/52 mmHg, pulse is 133/min, respirations are 25/min, and oxygen saturation is 99% on room air. Physical exam is notable for an altered man. Cardiopulmonary exam reveals a murmur over the left lower sternal border. A bedside ultrasound reveals a vegetation on the tricuspid valve. The patient is ultimately started on IV fluids, norepinephrine, vasopressin, vancomycin, and piperacillin-tazobactam. A central line is immediately placed in the internal jugular vein and the femoral vein secondary to poor IV access. Cardiothoracic surgery subsequently intervenes to remove the vegetation. While recovering in the ICU, days 3-5 are notable for an improvement in the patient’s symptoms. Two additional peripheral IVs are placed while in the ICU on day 5, and the femoral line is removed. On day 6, the patient's fever and hemodynamic status worsen. Though he is currently responding and not complaining of any symptoms including headache, photophobia, neck stiffness, or pain, he states he is feeling weak. Jolt accentuation of headache is negative and his abdominal exam is benign. A chest radiograph, urinalysis, and echocardiogram are unremarkable though the patient’s blood cultures are positive when drawn. Which of the following is the best next step in management?