Minor criteria

Blood urea nitrogen level = 20 mg per dL (7.14 mmol per L)

Confusion/disorientation

Hypotension requiring aggressive fluid resuscitation

Hypothermia (core temperature < 96.8° F [36° C])

Leukopenia (white blood cell count < 4,000 per mm3 [4.00 × 109 per L])

Multilobar infiltrates

PaO2/FiO2 ratio ≤ 250

Respiratory rate ≥ 30 breaths per minute

Thrombocytopenia (platelet count < 100 × 103 per mm3 [100 × 109 per L])

Major criteria

Invasive mechanical ventilation

Septic shock with need for vasopressors