Portsmouth POSSUM: predicts 30-day mortality after general surgery
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Disclaimer: The clinical scoring and algorithms on this platform are intended strictly for professional informational purposes. They do not constitute a definitive medical diagnosis, treatment, or clinical decision. The final judgment and responsibility lie with the treating physician.
Yasal Uyarı: Bu platformdaki klinik skorlamalar ve algoritmalar yalnızca sağlık profesyonellerini bilgilendirme amaçlıdır. Herhangi bir kesin tıbbi teşhis, tedavi veya klinik karar yerine geçemez. Nihai karar ve sorumluluk hastayı yatak başında değerlendiren hekime aittir.
P-POSSUM (Portsmouth Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity) was developed by Prytherch et al. (Br J Surg 1998) as a recalibration of the original POSSUM score, which systematically over-predicted mortality — particularly at low risk levels. P-POSSUM uses the same 18 variables (12 physiological: age, cardiac, respiratory, SBP, pulse, GCS, Hb, WBC, urea, sodium, potassium, ECG; and 6 operative: severity, multiple procedures, blood loss, peritoneal soiling, malignancy, urgency) but applies a corrected equation: ln(R/1−R) = −12.12 + 0.1692 × Physiological Score + 0.1550 × Operative Score. It is the most widely used general surgical mortality prediction tool in UK national surgical audit databases.
The urgency of surgery (elective vs. emergency) is one of the highest-leverage parameters in the P-POSSUM operative score — it contributes a 3-point differential (4 vs. 1) that maps to a clinically meaningful increase in predicted mortality. Pre-optimizing a patient to convert an emergency procedure to a planned elective operation — for example, by achieving source control through CT-guided percutaneous drainage of a diverticular abscess — is the most impactful way to reduce predicted P-POSSUM mortality before the patient reaches the theatre.
Prytherch DR, Whiteley MS, Higgins B, et al. POSSUM and Portsmouth POSSUM for predicting mortality. Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity. Br J Surg. 1998;85(9):1217-1220. doi:10.1046/j.1365-2168.1998.00840.x. PMID: 9752863
Copeland GP, Jones D, Walters M. POSSUM: a scoring system for surgical audit. Br J Surg. 1991;78(3):355-360. doi:10.1002/bjs.1800780341. PMID: 2021856
Disclaimer: The clinical scoring and algorithms on this platform are intended strictly for professional informational purposes. They do not constitute a definitive medical diagnosis, treatment, or clinical decision. The final judgment and responsibility lie with the treating physician.
Complete physiological parameters pre-operatively and operative parameters intraoperatively or immediately post-operatively. P-POSSUM is the preferred variant over the original POSSUM for general surgical populations because it avoids the systematic over-prediction of mortality that leads to over-triage. Use it to: (1) provide individualized mortality risk estimates for consent, (2) guide HDU/ICU allocation, and (3) benchmark unit outcomes against expected P-POSSUM mortality.
The urgency of surgery (elective vs. emergency) is one of the highest-leverage parameters in the operative score — it adds 4 points vs. 1, a differential of 3 points that corresponds to a meaningful jump in predicted mortality. Pre-optimizing a patient to allow an elective approach (e.g., PTGBD for cholecystitis, PCD for diverticular abscess) is the single most impactful way to reduce P-POSSUM predicted mortality before the patient reaches the operating theatre.
P-POSSUM is a general surgical tool. Subspecialty-specific POSSUM variants exist and are better calibrated for their populations: CR-POSSUM for colorectal surgery, O-POSSUM for oesophagogastric surgery, and Vascular POSSUM for vascular procedures. Using P-POSSUM for these subspecialties will produce less accurate mortality predictions than using the dedicated variant.