New disorientation to person/place/time OR Abbreviated Mental Test Score ≤ 8 (not chronic baseline cognitive impairment).
Serum urea > 7 mmol/L (BUN > 19 mg/dL).
Respiratory rate at presentation ≥ 30 breaths/min — count for a full 60 s when abnormal.
Either SBP < 90 mmHg OR DBP ≤ 60 mmHg satisfies the criterion.
Patient age 65 or above at presentation.