SAPS II Calculator
Calculate the Simplified Acute Physiology Score II (SAPS II) for ICU patients. SAPS II uses 17 variables including age, vital signs, labs, and chronic diseases to predict in-hospital mortality. Validated on 13,152 patients across 137 ICUs.
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Demographics & Admission
Vital Signs (Worst in 24h)
Respiratory & Renal
Labs
Recommendations
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⚠️For informational purposes only — not medical advice. Consult a healthcare professional before acting on results.
SAPS II was developed by Le Gall et al. in 1993 as a severity scoring system for ICU patients. It predicts hospital mortality using 17 variables from the first 24 hours: age, vital signs (HR, SBP, temp), respiratory (PaO2/FiO2 if ventilated), renal (urine output, BUN), metabolic (K, Na, HCO3), hepatic (bilirubin), hematologic (WBC), neurological (GCS), chronic disease, and admission type. Validated on 13,152 patients across 137 ICUs.
Sources: Le Gall JR JAMA 1993.
Key Takeaways
- • Use worst values from first 24 hours in ICU.
- • GCS: pre-sedation or estimated. PaO2/FiO2 only if ventilated.
- • Score converted to mortality probability via logit equation.
- • SAPS II may overestimate mortality in modern ICUs; use with clinical judgment.
Did You Know?
How Does SAPS II Work?
Scoring
Each variable gets 0 to max points based on thresholds. Sum all 17 components. Mortality = logit equation: 100 / (1 + exp(-(-7.7631 + 0.0737×score + 0.9971×ln(score+1)))).
Timing
Collect worst values in first 24h. GCS before sedation. Urine output = total in 24h.
Applications
ICU benchmarking, clinical trials, prognostication, goals of care. Do not use as sole basis for withdrawal.
Expert Tips
SAPS II Risk Reference
| Score | Risk | Mortality |
|---|---|---|
| 0-29 | Low | <10% |
| 30-49 | Moderate | 10-25% |
| 50-69 | High | 25-50% |
| 70+ | Very High | >50% |
Frequently Asked Questions
What is SAPS II?
The Simplified Acute Physiology Score II (SAPS II) is a severity scoring system for ICU patients that predicts hospital mortality. It uses 17 variables from the first 24 hours of ICU admission: age, vital signs, labs, GCS, chronic disease, and admission type. Validated on 13,152 patients across 137 ICUs. Score range 0-163; higher scores predict higher mortality.
How is SAPS II calculated?
Each variable is assigned points based on worst values in the first 24h. Age (0-18 pts), heart rate (0-11), systolic BP (0-13), temperature (0-3), PaO2/FiO2 if ventilated (0-11), urine output (0-11), BUN (0-10), WBC (0-12), potassium (0-3), sodium (0-5), bicarbonate (0-6), bilirubin (0-9), GCS (0-26), chronic disease (0-17), admission type (0-8). Total score is converted to mortality probability via logit equation.
When should SAPS II be used?
At 24 hours after ICU admission. Use worst values in the first 24h. GCS should be pre-sedation or estimated. PaO2/FiO2 is only scored if mechanically ventilated. SAPS II is used for ICU benchmarking, clinical trials, quality improvement, and prognostication. Not for individual treatment decisions alone.
What is the mortality prediction?
Mortality probability is calculated from the SAPS II score using a logit equation. Typical ranges: 0-29 score <10% mortality; 30-49 about 10-25%; 50-69 about 25-50%; 70+ >50%. SAPS II may overestimate mortality in modern ICUs due to improved care since the 1990s.
Who should use this calculator?
Intensivists, ICU nurses, and clinicians involved in critical care. SAPS II supports quality benchmarking, research stratification, and goals of care discussions. Always combine with clinical judgment. Do not use as sole basis for withdrawal of care.
Can this replace medical advice?
No. This tool is for educational purposes only. Clinical decisions require professional assessment. Always consult a qualified healthcare provider. SAPS II predicts population-level outcomes, not individual prognosis. Goals of care should involve the full care team and family.
Key Statistics
Official Data Sources
⚠️ Disclaimer: This calculator is for educational purposes only. It is not a substitute for professional medical advice. SAPS II predicts population-level outcomes, not individual prognosis. Do not use as sole basis for treatment or withdrawal decisions. Always consult a qualified healthcare provider. Goals of care should involve the full care team and family.