SIRS & Sepsis Calculator Septic Shock Criteria Screen
Rapidly screen for Systemic Inflammatory Response Syndrome (SIRS) and evaluate the clinical continuum of Sepsis, Severe Sepsis, and Septic Shock to initiate life-saving early goal-directed therapy.
1. Vital Signs & Labs (SIRS Criteria)
2. Clinical Context (Sepsis Continuum)
Enter patient vitals and clinical status to calculate the SIRS Score and Sepsis Diagnosis.
Understanding the SIRS & Sepsis Continuum
Originally defined by the 1992 ACCP/SCCM Consensus Conference, Systemic Inflammatory Response Syndrome (SIRS) represents a robust clinical, physiologic response to a non-specific insult (which could be infectious or non-infectious, such as trauma, burns, or pancreatitis). When SIRS is triggered by a suspected or confirmed infection, the patient is formally diagnosed with Sepsis.
The 4 SIRS Criteria
A patient must meet ≥ 2 of the following criteria to be positive for SIRS:
- Temperature: > 38.0°C (100.4°F) or < 36.0°C (96.8°F)
- Heart Rate: > 90 beats per minute
- Respiratory Rate: > 20 breaths per minute or PaCO₂ < 32 mmHg
- White Blood Cell Count: > 12,000 cells/mm³, < 4,000 cells/mm³, or > 10% immature (band) forms
Clinical Definitions (Sepsis-2 Legacy Model)
While newer models exist, the Sepsis-2 continuum remains deeply ingrained in clinical screening pathways and CMS (Centers for Medicare & Medicaid Services) core measure reporting:
| Condition | Required Criteria | Clinical Action |
|---|---|---|
| SIRS | ≥ 2 SIRS Criteria met. | Investigate underlying cause (trauma, ischemia, infection). |
| Sepsis | SIRS + Suspected/Confirmed Infection. | Obtain blood cultures, measure lactate, administer broad-spectrum IV antibiotics. |
| Severe Sepsis | Sepsis + End-organ dysfunction (e.g., Lactate > 2, altered mental status, acute kidney injury). | Initiate 30 mL/kg IV crystalloid fluid resuscitation immediately. |
| Septic Shock | Severe Sepsis + Refractory hypotension requiring vasopressors to maintain MAP ≥ 65 despite fluid resuscitation. | Central venous access, vasopressor initiation (Norepinephrine preferred), intensive care admission. |
The Shift to Sepsis-3 (2016 Guidelines)
In 2016, the Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3) redefined Sepsis as “life-threatening organ dysfunction caused by a dysregulated host response to infection.”
Under Sepsis-3, the term “Severe Sepsis” was retired, and SIRS was removed as the strict defining criteria, replaced by the SOFA (Sequential Organ Failure Assessment) score and the qSOFA screening tool. However, multiple subsequent studies have demonstrated that while qSOFA is highly specific for mortality, SIRS remains significantly more sensitive for early screening. Thus, SIRS is still universally utilized in emergency departments for early sepsis alert triggers.
