Clinical Reference

SIRS (Systemic Inflammatory Response Syndrome) is defined by meeting two or more of the following criteria:

• Temperature: > 38°C (100.4°F) OR < 36°C (96.8°F)
• Heart Rate: > 90 beats per minute
• Respiratory Rate: > 20 breaths per minute OR PaCO2 < 32 mmHg
• WBC Count: > 12,000/mm³ OR < 4,000/mm³ OR > 10% bands

Note: SIRS is a non-specific finding and can be caused by ischemia, inflammation, trauma, infection, or several other insults. It is no longer part of the strict definition of Sepsis (Sepsis-3) but remains a useful bedside tool.