What are the current criteria for diagnosing sepsis?

Current Sepsis Criteria

The current sepsis criteria are based on the Sepsis-3 definition, which defines sepsis as life-threatening organ dysfunction caused by a dysregulated host response to infection, operationalized as an increase in the Sequential Organ Failure Assessment (SOFA) score of 2 points or more. 1

Sepsis-3 Diagnostic Framework

Definition of Sepsis

Sepsis is defined as:

• Life-threatening organ dysfunction
• Caused by a dysregulated host response to infection
• Operationalized as an increase in SOFA score ≥2 points (associated with in-hospital mortality >10%)

Quick SOFA (qSOFA) Screening Tool

For rapid bedside assessment in out-of-hospital, emergency department, or general ward settings, qSOFA identifies patients at higher risk with at least 2 of:

• Respiratory rate ≥22/min
• Altered mentation
• Systolic blood pressure ≤100 mmHg

Septic Shock Definition

Septic shock is defined as:

• A subset of sepsis with profound circulatory, cellular, and metabolic abnormalities
• Clinically identified by:
  • Vasopressor requirement to maintain MAP ≥65 mmHg
  • Serum lactate >2 mmol/L (>18 mg/dL) despite adequate fluid resuscitation
• Associated with hospital mortality rates >40%

Sequential Organ Failure Assessment (SOFA) Score Components

The SOFA score evaluates six organ systems, with points assigned from 0-4 for each system:

1. Respiratory: PaO2/FiO2 ratio
2. Coagulation: Platelet count
3. Liver: Bilirubin level
4. Cardiovascular: Hypotension and vasopressor requirements
5. Central Nervous System: Glasgow Coma Scale
6. Renal: Creatinine level or urine output

Important Clinical Considerations

Limitations of Previous Criteria

The Sepsis-3 criteria replaced the older SIRS-based criteria (Sepsis-1 and Sepsis-2) due to:

• Excessive focus on inflammation in previous definitions
• Misleading continuum model through severe sepsis to shock
• Inadequate specificity and sensitivity of SIRS criteria 1

Performance of Screening Tools

It's important to note that qSOFA has demonstrated limitations in sensitivity:

• Studies show qSOFA has lower sensitivity (36.3% for ICU admission, 68% for 48-hour mortality) compared to SIRS criteria in prehospital and ED settings 2
• NEWS2 (National Early Warning Score 2) has shown superior performance to qSOFA in detecting sepsis with organ dysfunction in emergency departments 3

Pediatric Considerations

Diagnostic criteria for sepsis in the pediatric population differ and include:

• Signs and symptoms of inflammation plus infection with hyper- or hypothermia (rectal temperature >38.5°C or <35°C)
• Tachycardia (may be absent in hypothermic patients)
• At least one indication of altered organ function: altered mental status, hypoxemia, increased serum lactate, or bounding pulses 4

Clinical Application

The current approach to sepsis diagnosis emphasizes:

1. Identifying suspected infection
2. Assessing for organ dysfunction using SOFA score
3. Using qSOFA as a rapid bedside screening tool to identify patients who may need closer monitoring
4. Recognizing septic shock through the combination of vasopressor requirements and elevated lactate

Early recognition and prompt treatment remain critical for improving outcomes, as sepsis is a time-dependent condition with significant mortality risk 5.