A 72-year-old man presents with cough, fever, and pleuritic chest pain. Chest radiograph shows a right lower lobe infiltrate. He is tachypneic with a respiratory rate of 32/min, blood pressure 86/54 mm Hg, and confusion. Which factor alone in this patient most strongly supports need for ICU-level care according to ATS/IDSA criteria for severe community-acquired pneumonia?