This calculator is for general information and education. It is not medical advice and does not replace the judgment of a doctor, nurse or pharmacist who knows the full clinical picture.
The Simplified Acute Physiology Score II (SAPS II) was published by Jean-Roger Le Gall, Stanley Lemeshow and Fabienne Saulnier in 1993, from 13,152 patients in 137 intensive care units in Europe and North America. It measures the severity of illness during the first 24 hours in the ICU and converts it into a predicted hospital mortality. Like APACHE II, it is used to describe and compare patient populations and ICU performance rather than to decide care for one patient.
The 17 variables
- Age: from 0 points under 40 to 18 points at 80 or older.
- 12 physiological variables, using the worst value in the first 24 hours: heart rate, systolic blood pressure, temperature, PaO2/FiO2 if ventilated or on CPAP, urine output, blood urea nitrogen, white blood cells, potassium, sodium, bicarbonate, bilirubin and Glasgow coma scale.
- Chronic disease: metastatic cancer (9), hematologic malignancy (10) or AIDS (17).
- Type of admission: scheduled surgery (0), medical (6) or unscheduled surgery (8).
The Glasgow score is the one estimated before sedation. The heaviest item is a Glasgow score under 6, at 26 points. The total runs from 0 to 163.
Predicted mortality
Le Gall’s logistic equation converts the score into a probability of death in hospital:
logit = −7.7631 + 0.0737 × SAPS II + 0.9971 × ln(SAPS II + 1)
mortality = e^logit ÷ (1 + e^logit)
| SAPS II | Predicted hospital mortality |
|---|---|
| 20 | about 4% |
| 30 | about 11% |
| 40 | about 25% |
| 49 | about 44% |
| 60 | about 68% |
| 80 | about 92% |
Example
A medical patient aged 65 (12 points) with a heart rate of 130 (4), a systolic pressure of 90 (5), ventilated with a PaO2/FiO2 of 150 (9), 0.8 L of urine in 24 hours (4), a BUN of 40 mg/dL (6) and a bicarbonate of 17 mmol/L (3) scores 49, a predicted hospital mortality of about 44%.
Limits
Calibration has drifted since 1993: in many recent cohorts SAPS II overestimates mortality, and SAPS 3 (2005) or locally recalibrated versions are preferred for benchmarking. Missing values are scored as normal, which underestimates severity. The score describes groups of patients; it should never be used alone to limit or withdraw treatment from an individual.