A 64-year-old woman presents to the emergency room with flank pain and fever. She noted dysuria for the past 3 days. Blood and urine cultures are obtained, and she is started on intravenous ciprofloxacin. Six hours after admission, she becomes tachycardic and her blood pressure drops. Her intravenous fluid is normal saline (NS) at 100 mL/h. Her current blood pressure is 79/43 mm Hg, heart rate is 128/min, respiratory rate is 26/min, and temperature is 39.2degC (102.5degF). She seems drowsy yet uncomfortable. Extremities are warm with trace edema. What is the best next course of action?