Which vital signs/conditions are part of the Systemic Inflammatory Response Syndrome (SIRS) criteria?

The criteria for Systemic Inflammatory Response Syndrome (SIRS) are specifically designed to help identify a systemic response to inflammation, which can be caused by various underlying conditions such as infection or trauma. The SIRS criteria include:

1. Body temperature greater than 38°C (100.4°F) or less than 36°C (96.8°F)

2. Heart rate greater than 90 beats per minute (tachycardia)

3. Respiratory rate greater than 20 breaths per minute or arterial carbon dioxide tension (PaCO2) less than 32 mmHg (tachypnea)

4. Abnormal white blood cell (WBC) count, either greater than 12,000 cells/mm³ or less than 4,000 cells/mm³ or with more than 10% band forms (immature neutrophils).

In this context, the presence of a low white blood cell count (leukopenia) along with fever and tachycardia fits the SIRS criteria effectively. The combination of these three vital signs indicates an inflammatory response and is critical for diagnosing potential systemic issues.

While fever and tachycardia are consistently part of the SIRS criteria, the specific combination of low WBC count,