SIRS Criteria (≥ 2 Required)

• Temperature > 38°C or < 36°C
• Heart rate > 90 bpm
• Respiratory rate > 20 or PaCO₂ < 32 mmHg
• WBC > 12,000, < 4,000, or > 10% bands

Sepsis

• Suspected or confirmed infection AND
• ≥ 2 SIRS criteria

Severe Sepsis

• Sepsis AND evidence of acute organ dysfunction, such as:
• Hypotension responsive to fluids
• Lactate ≥ 2 mmol/L
• Creatinine elevation or oliguria
• Acute mental status change
• Platelets < 100,000
• Bilirubin > 2 mg/dL
• Acute respiratory failure requiring supplemental O₂ or ventilation
• INR > 1.5 (not on anticoagulation)

Septic Shock

• Severe sepsis AND either:
• Persistent hypotension despite adequate fluid resuscitation
• Lactate ≥ 4 mmol/L even if blood pressure is normal