ToolsCalculators
POSSUM score for operative morbidity and mortality risk
Predicts 30-day morbidity and mortality after general/vascular surgery from physiological reserve and operative severity.
POSSUM score for operative morbidity and mortality risk
Age
Cardiac signs
Respiratory history
Systolic blood pressure
Pulse rate
Glasgow Coma Scale
Haemoglobin
White cell count
Serum urea
Serum sodium
Serum potassium
ECG
Operative severity
Number of procedures within 30 days
Blood loss per operation
Peritoneal soiling
Presence of malignancy
Timing of surgery
Result1.1 % predicted mortality
Predicted morbidity 5.5 % and mortality 1.1 % using the original Copeland logistic equations.
- Predicted 30-day mortality
- 1.1 %
- Predicted morbidity
- 5.5 %
- Physiological score
- 12
- Operative severity score
- 6
When to use
- Auditing and case-mix adjusting surgical outcomes across units or surgeons.
- Estimating an individual patient's risk of 30-day morbidity and mortality before major general, vascular, or orthopaedic surgery.
Formula
Physiological score (12 items, each scored 1/2/4/8, range 12-88) and operative severity score (6 items, each scored 1/2/4/8, range 6-44) are summed separately. ln(morbidity/(1-morbidity)) = -5.91 + 0.16 x physiological score + 0.19 x operative score. ln(mortality/(1-mortality)) = -7.04 + 0.13 x physiological score + 0.16 x operative score.
Pearls and pitfalls
- Original POSSUM over-predicts mortality in low-risk patients; the Portsmouth modification (P-POSSUM) was later developed to correct this.
- Best used for comparative audit of units/surgeons rather than as the sole basis for an individual consent discussion.