What is the current sepsis protocol using SOFA (Sequential Organ Failure Assessment) score versus SIRS (Systemic Inflammatory Response Syndrome) criteria in Sepsis-3?

Sepsis-3 Protocol: SOFA Score Replaces SIRS Criteria

The current standard for sepsis diagnosis uses the SOFA score (≥2 point increase) to identify organ dysfunction, while SIRS criteria have been removed from the sepsis definition and qSOFA serves as a rapid bedside screening tool—not a diagnostic criterion. 1, 2

Core Sepsis-3 Definitions

Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection, operationalized as an increase in SOFA score of ≥2 points, which correlates with in-hospital mortality >10%. 3, 2, 4

Septic shock is identified by:

• Vasopressor requirement to maintain MAP ≥65 mmHg AND
• Serum lactate >2 mmol/L (>18 mg/dL) despite adequate fluid resuscitation 3, 2, 5

The concept of "severe sepsis" is now obsolete and should not be used. 2

Why SOFA Replaced SIRS

The SOFA score demonstrates superior prognostic accuracy compared to SIRS criteria:

• SOFA score shows high discriminative ability with AUC of 0.89 for sepsis diagnosis and 0.75-0.72 for mortality prediction 4
• SOFA score >11 achieves 100% sensitivity and negative predictive value for sepsis diagnosis 4
• SIRS criteria had high sensitivity but very low specificity, leading to overdiagnosis 6, 7
• SIRS presence was associated with 3.5-fold increased risk of organ dysfunction, but the revised definition better identifies truly life-threatening cases 7

SOFA Score Components

The SOFA score assesses six organ systems (0-4 points each): 3, 1

Respiratory:

• PaO2/FiO2 <400: 1 point
• <300: 2 points
• <200 with mechanical ventilation: 3 points
• <100 with mechanical ventilation: 4 points 3

Cardiovascular:

• MAP <70 mmHg: 1 point
• Dopamine ≤5 or dobutamine (any): 2 points
• Dopamine >5 OR epinephrine ≤0.1 OR norepinephrine ≤0.1: 3 points
• Dopamine >15 OR epinephrine >0.1 OR norepinephrine >0.1: 4 points 3

Hepatic, Coagulation, Renal, and Neurological systems are similarly scored 3, 1

A modified cardiovascular SOFA incorporating lactate levels shows even higher predictive validity (AUC 0.716 vs 0.638) and identifies more at-risk patients (92.6% vs 89.5%). 8

Quick SOFA (qSOFA) for Rapid Screening

qSOFA consists of three bedside criteria (≥2 indicates higher risk): 1, 2, 6

• Respiratory rate ≥22 breaths/min
• Altered mental status (GCS ≤13)
• Systolic blood pressure ≤100 mmHg

Critical distinction: qSOFA is a screening tool to prompt further evaluation, NOT a diagnostic criterion for sepsis. 2, 6

Performance characteristics:

• qSOFA shows 96.1% specificity but only 29.7% sensitivity for organ dysfunction 7
• High specificity makes it useful for identifying high-risk patients, but poor sensitivity means negative qSOFA does not rule out sepsis 6, 7
• qSOFA had similar discriminative ability to SIRS (AUC 0.73 vs 0.72) but identifies a different patient population 7

Clinical Implementation Algorithm

Step 1: Identify suspected infection (documented or clinical suspicion with fever, hypothermia, leukocytosis, elevated procalcitonin/CRP) 1

Step 2: Calculate qSOFA at bedside

• If qSOFA ≥2: High-risk patient requiring immediate full SOFA assessment 1, 2
• If qSOFA <2: Still calculate full SOFA score—do not rely on qSOFA alone 6, 7

Step 3: Calculate full SOFA score

• Baseline SOFA assumed to be 0 unless chronic organ dysfunction documented
• Sepsis diagnosed if SOFA increases ≥2 points 3, 2, 4
• SOFA >11 indicates very high mortality risk requiring aggressive intervention 4

Step 4: Assess for septic shock

• Check if vasopressors needed for MAP ≥65 mmHg
• Measure lactate (>2 mmol/L confirms shock if on vasopressors) 3, 5

Step 5: Risk-stratified monitoring

• High-risk patients: Re-evaluate every 30 minutes 1
• Moderate-risk: Every hour 1
• Low-risk: Every 4-6 hours 1

Common Pitfalls to Avoid

Do not dismiss patients with negative qSOFA—29.7% sensitivity means most patients with organ dysfunction will have qSOFA <2. 7

Do not use SIRS criteria for sepsis diagnosis—while SIRS remains associated with adverse outcomes, it is no longer part of the formal definition and leads to overdiagnosis. 2, 6, 7

Do not confuse qSOFA with SOFA—qSOFA prompts evaluation but only SOFA (≥2 point increase) diagnoses sepsis. 2, 6

In resource-limited settings, the complexity of SOFA scoring may be challenging; qSOFA provides a feasible alternative for initial triage, but recognize its limitations. 3

For elderly or immunocompromised patients, expect attenuated inflammatory responses—they may have severe sepsis with minimal SIRS criteria or lower qSOFA scores. 3, 2

Special Consideration: Sepsis-Induced Coagulopathy (SIC)

For patients with thrombocytopenia, calculate SIC score (platelet count + PT ratio + SOFA score): 3, 1

• SIC score ≥4 identifies coagulopathy requiring specific interventions
• SIC-positive patients have higher mortality (32.5-37.2%) 3
• SIC shows 95.7% negative predictive value for overt DIC 3