What is the management approach for critically ill patients with a SOFA (Sequential Organ Failure Assessment) score of 6 or higher, indicating potential organ failure?

SOFA Score: Six Organ Systems Assessed

Core Components of the SOFA Score

The SOFA (Sequential Organ Failure Assessment) score evaluates dysfunction across six organ systems, with each system scored 0-4 points for a total possible score of 0-24, where higher scores indicate worse organ dysfunction and increased mortality risk. 1, 2

The six organ systems assessed are:

1. Respiratory System (Lungs)

• Evaluated via PaO₂/FiO₂ ratio 1, 2
• Score 0: ≥400 mmHg 1
• Score 1: <400 mmHg 1
• Score 2: <300 mmHg 1
• Score 3: <200 mmHg 1
• Score 4: <100 mmHg with mechanical ventilation 1, 2

2. Cardiovascular System (Heart)

• Assessed through mean arterial pressure (MAP) and vasopressor requirements 1, 2
• Score 0: No hypotension, MAP ≥70 mmHg 1, 2
• Score 1: MAP <70 mmHg 1
• Score 2: Dopamine ≤5 μg/kg/min 1
• Score 3: Dopamine >5 μg/kg/min OR epinephrine ≤0.1 μg/kg/min OR norepinephrine ≤0.1 μg/kg/min 1
• Score 4: Dopamine >15 μg/kg/min OR epinephrine >0.1 μg/kg/min OR norepinephrine >0.1 μg/kg/min 1, 2

3. Neurological System (Brain)

• Evaluated using Glasgow Coma Scale (GCS) 1, 2
• Score 0: GCS 15 1
• Score 1: GCS 13-14 1
• Score 2: GCS 10-12 1
• Score 3: GCS 6-9 1
• Score 4: GCS <6 1, 2

4. Hepatic System (Liver)

• Assessed via serum bilirubin levels 1, 2
• Score 0: <1.2 mg/dL (<20 μmol/L) 1
• Score 1: 1.2-1.9 mg/dL (20-32 μmol/L) 1
• Score 2: 2.0-5.9 mg/dL (33-100 μmol/L) 1
• Score 3: 6.0-11.9 mg/dL (101-203 μmol/L) 1
• Score 4: >12 mg/dL (>203 μmol/L) 1, 2

5. Renal System (Kidneys)

• Evaluated through serum creatinine levels and/or urine output 1, 2
• Score 0: <1.2 mg/dL (<106 μmol/L) 1
• Score 1: 1.2-1.9 mg/dL (106-168 μmol/L) 1
• Score 2: 2.0-3.4 mg/dL (169-300 μmol/L) 1
• Score 3: 3.5-4.9 mg/dL (301-433 μmol/L) 1
• Score 4: >5.0 mg/dL (>434 μmol/L) OR urine output <200 mL/day 1, 2
• Note: 4 points may be given for renal replacement therapy 1

6. Coagulation System (Hemostasis)

• Measured by platelet count 1, 2
• Score 0: ≥150 × 10³/μL 1
• Score 1: <150 × 10³/μL 1
• Score 2: <100 × 10³/μL 1
• Score 3: <50 × 10³/μL 1
• Score 4: <20 × 10³/μL 1, 2

Clinical Application and Timing

Calculate SOFA score on ICU admission using the most abnormal values from the first 24 hours, then reassess every 48-72 hours throughout the ICU stay to track disease progression and treatment response. 2, 3

• Serial assessment during the first few days of ICU admission is a good indicator of prognosis 3
• Both the mean and highest SOFA scores during ICU stay are particularly useful predictors of outcome 3
• An increase in SOFA score during the first 48 hours predicts mortality of at least 50%, regardless of initial score 3

Prognostic Significance by Score Range

• SOFA score >10: Predicts mortality in 93% of cases 1, 2
• SOFA score >11: Associated with mortality exceeding 80-90% 2, 3
• Initial scores >11: Correspond to mortality >90% 3
• Mean scores >5: Correspond to mortality >80% 3

Special Clinical Context: Sepsis Definition

In the presence of documented or suspected infection, a SOFA score increase of ≥2 points from baseline defines sepsis according to Sepsis-3 criteria, triggering immediate broad-spectrum antibiotics within 1 hour, fluid resuscitation, and source control. 2, 4

Critical Limitations

• SOFA does not incorporate gastrointestinal or immune dysfunction due to insufficient data and lack of content validity 4, 5
• The score does not consider patient age or comorbidities, unlike APACHE II scoring systems 2, 4, 6
• Do not use SOFA alone for triage decisions in non-pandemic settings, as it lacks validation for resource allocation at low scores 2, 7
• Using SOFA as a triage tool would exclude many patients who would otherwise survive—mortality for the highest category (>11 points) is 53-58%, meaning 42-47% still survive 7