P-POSSUM (Portsmouth-recalibrated mortality)
P-POSSUM — the Portsmouth recalibration of POSSUM: the identical 18 variables with a better-calibrated mortality equation, reported alongside the original POSSUM mortality.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Age
- 4
- Cardiac status
- 2
- Respiratory status
- 2
- Systolic blood pressure
- 2
- Pulse
- 4
- Glasgow Coma Score
- 1
- Hemoglobin
- 4
- White-cell count
- 2
- Urea
- 4
- Sodium
- 2
The other 8 values
- Potassium
- 1
- ECG
- 4
- Operative severity
- 4
- Number of procedures
- 1
- Blood loss
- 4
- Peritoneal soiling
- 4
- Malignancy
- 1
- Urgency
- 4
Result: P-POSSUM physiological score 32, operative score 18: recalibrated predicted mortality 29.7% (original POSSUM equation 50%).
The tool opens with these values already filled in. Replace them with your own.
What the result means
- Divergence
- at the minimum 12/6 scores POSSUM predicts ~1.1% but P-POSSUM ~0.2% — the better-calibrated low-risk estimate. Both are kept and cross-linked.
What you enter
- Age (point grade)
- Cardiac status (point grade)
- Respiratory status (point grade)
- Systolic blood pressure (point grade)
- Pulse (point grade)
- Glasgow Coma Score (point grade)
- Hemoglobin (point grade)
- White-cell count (point grade)
- Urea (point grade)
- Sodium (point grade)
The other 8 fields
- Potassium (point grade)
- ECG (point grade)
- Operative severity (point grade)
- Number of procedures (point grade)
- Blood loss (point grade)
- Peritoneal soiling (point grade)
- Malignancy (point grade)
- Urgency (point grade)
How this is calculated
- Equation
- recalibrated mortality ln[R/(1−R)] = −9.065 + 0.1692·phys + 0.1550·op, on the identical 18 POSSUM variables.
Prytherch DR, Whiteley MS, Higgins B, et al. POSSUM and Portsmouth POSSUM for predicting mortality. Br J Surg. 1998;85(9):1217-1220. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.