SAPS II Calculator
Simplified Acute Physiology Score (SAPS) II calculator to predict hospital mortality
ClinCalc.com » Critical Care » Simplified Acute Physiology Score (SAPS II) Calculator
Use the worst value for each physiological variable within the past 24 hours.
US units
RESULTS
Estimated mortality:
83.8%
| 1. Age 70-74 yrs | 15 | 21.4% |
| 2. Urine output < 500 mL/day | 11 | 15.7% |
| 3. P:F ratio 100-199 | 9 | 12.9% |
| 4. Medical admission | 6 | 8.6% |
| 5. Bicarbonate < 15 mEq/L | 6 | 8.6% |
| 6. BUN 28-83 mg/dL | 6 | 8.6% |
| 7. Glasgow coma score 11-13 | 5 | 7.1% |
| 8. Systolic BP 70-99 mmHg | 5 | 7.1% |
| 9. HR 120-159 bpm | 4 | 5.7% |
| 10. Temp ≥ 39°C | 3 | 4.3% |
| 11. No chronic diseases | 0 | 0% |
| 12. WBC 1.0-19.9 (103/cu mm) | 0 | 0% |
| 13. Potassium 3.0-4.9 mEq/dL | 0 | 0% |
| 14. Sodium 125-144 mEq/L | 0 | 0% |
| 15. Bilirubin < 4 mg/dL | 0 | 0% |
About This Calculator
The Simplified Acute Physiology Score (SAPS II) is a severity score and mortality estimation tool developed from a large sample of medical and surgical patients in North America and Europe.1
Sample Inclusion and Exclusion
The study analyzed a total of 12,997 patients from 137 medical, surgical, or mixed intensive care units in 12 countries from 9/30/1991 to 12/27/1991. Patients with burn injuries, coronary care unit patients, and cardiac surgery patients were excluded from analysis.
Study Variables
The SAPS II score is made of 12 physiological variables and 3 disease-related variables. The worst physiological variables were collected within the first 24 hours of ICU admission. The "worst" measurement was defined as the measure that correlated to the highest number of points. The study did not continually calculate SAPS II scores beyond the first 24 hours of ICU admission. The SAPS II score ranges from 0 to 163 points.
Correlation of Total Score and Hospital Mortality
Hospital mortality may be calculated using the following equation:
$$
\\ logit = -7.7631 + 0.0737*Score + 0.9971*ln(Score+1)
\\ Mortality = \frac{e^{logit}}{1+e^{logit}}
$$
Ability to Predict Hospital Mortality
The study used a pre-defined 65% of the patient population to define the SAPS II criteria, and the remaining 35% for validation purposes. The area under the ROC curve in the validation group was 0.86 (95% CI: 0.84 to 0.88). This AUC was considered superior to the previous SAPS score, which demonstrated an AUC ROC of 0.80.
Note that there is a sigmoidal relationship between mortality and the total SAPS II score, as demonstrated by the graph below:
| 10% |
29 pts |
| 25% |
40 pts |
| 50% |
52 pts |
| 75% |
64 pts |
| 90% |
77 pts |
References and Additional Reading
- Le Gall JR, Lemeshow S, Saulnier F. A new Simplified Acute Physiology Score (SAPS II) based on a European/North American multicenter study. JAMA. 1993;270(24):2957-63. PMID 8254858.