Cerebrovascular Disease in the Critically Ill
Ischemic stroke
Time is brain. The clock starts at last known well, not at symptom discovery or arrival. IV alteplase is offered within 4.5 hours (and in selected wake-up strokes with DWI-FLAIR mismatch); endovascular thrombectomy for large vessel occlusion within 6 hours, and up to 24 hours with favorable perfusion or DAWN/DEFUSE-3 imaging profiles. Blood pressure must be below 185/110 mmHg before lysis and below 180/105 for 24 hours afterward; otherwise permissive hypertension is acceptable unless pressures exceed 220/120 or there is end-organ injury. Do not give antiplatelets within 24 hours of lysis.
Intracerebral hemorrhage
Lower systolic pressure to about 140 mmHg (range 130-150) within 6 hours; avoid dropping below 130. Reverse anticoagulation emergently: vitamin K plus four-factor PCC for warfarin, idarucizumab for dabigatran, and PCC or andexanet for factor Xa inhibitors. Platelet transfusion for antiplatelet-associated ICH does not improve outcomes. Seizure prophylaxis is not routine.
Subarachnoid hemorrhage
Give nimodipine 60 mg every 4 hours for 21 days, secure the aneurysm early, and watch for rebleeding, hydrocephalus, hyponatremia, and delayed cerebral ischemia. Maintain euvolemia rather than prophylactic hypervolemia.
Cerebral venous thrombosis
Anticoagulate with heparin or low-molecular-weight heparin even when a hemorrhagic venous infarct is present, then transition to warfarin or a direct oral anticoagulant for 3-12 months depending on the underlying cause.
Trap: attributing a declining exam after SAH to sedation without excluding rebleeding or hydrocephalus, or giving steroids in ischemic stroke (harmful).
Rule of thumb: when in doubt about timing, ask the last known well, then calculate eligibility from that moment.