A 78-year-old man presents with dyspnea, hypoxemia, and pleuritic chest pain. On evaluation, the diagnosis of acute pulmonary thromboembolism is established by CT pulmonary angiography, which shows bilateral acute pulmonary thromboemboli (see figures). IV bolus and infusion of unfractionated heparin had been started when pulmonary embolism was suspected in the emergency department. 

His medical history is notable for a motor vehicle accident 18 days previously, with a nondepressed skull fracture, significant closed-head trauma, and some persistent concussive symptoms. Head CT scan was negative for hemorrhage following the accident. He also has a history of type 2 diabetes mellitus; nephropathy, with estimated creatinine clearance of 26 mL/minute/1.73 m² (0.43 mL/s/m²); moderate nonproliferative diabetic retinopathy; hypertension; gastroesophageal reflux disease; and transient ischemic attack 3 years ago. Current medications are metformin, dapagliflozin, quinapril, famotidine, and aspirin.

After returning from CT imaging, he deteriorates hemodynamically, with BP of 79/44 mm Hg and heart rate of 136/minute in sinus tachycardia. The patient is started on norepinephrine and requires escalating doses up to the hospital maximum (3.3 µg/kg/minute) to maintain a mean arterial pressure >60 mm Hg. Urine output is minimal. Extracorporeal membrane oxygenation is not immediately available at this hospital, and thrombolytic therapy is considered because it will be at least 90 minutes before a catheter-based intervention can be started.