POSSUM in colorectal surgery Dermot Burke The General Infirmary at Leeds

APACHE APACHE (1981) 34 physiological variables APACHE II (1985)12 physiological variables age and chronic health history. APACHE III (2001)17 physiologic variables age and chronic health history prior diagnosis

APACHE II Temperature - core Mean arterial pressure Heart rate Respiratory rate Oxygenation FIO2 Arterial pH Serum sodium Serum potassium Serum creatinine Haematocrit White blood cell count

APACHE II Developed for use in intensive care setting Takes no account of surgical insult

Jones HJ et al Value of a surgical high-dependency unit. Br J Surg Dec; 86: “The POSSUM score is the most appropriate of the currently available scores for general surgical practice…… in the estimation of risk of dying.”

What is POSSUM? Physiological and Operative Severity Score for the enUmeration of Morbidity and Mortality

What is POSSUM? A method of operative risk prediction that allows for case-mix

What is POSSUM? 18 variables 12 physiological6 operative

PhysiologicalOperative Age Operation Cardiac status Number of procedures ECG Blood loss Respiratory status Peritoneal contamination BP Extent of malignancy Pulse Elective / emergency GCS Hb WCC Urea Sodium Potassium

POSSUM maths Each variable divided into 1, 2, 3, or 4 levels weighting of 1, 2, 4 or 8 applied to that level Amount (ml) < – 1000 >1000 Weighting Level e.g. blood loss

Physiology weighting numbers added together to give a physiology score Operative weighting numbers added together to give an operative severity score Scores put into equations POSSUM maths

Original POSSUM equations Morbidity In [R/(1-R)] = (0.16*phys score) + ( 0.19*op sev score) Mortality In [R/(1-R)] = (0.13*phys score) + ( 0.16*op sev score) Minimum risk of mortality = 0.40%

P-POSSUM Minimum risk of mortality = 0.22% In [R/(1-R)] = (0.169*phys score) + (0.155*op sev score)

Differences between Possum and P-Possum The main difference is in the statistical method of analysis Difference in minimum risk of morbidity

POSSUMs around the body Lung surgeryBrunelli et al Ann Thorac Surg. 1999; 67 : Bariatric surgeryCagigas et al Obes Surg. 1999; 9: Ruptured AAALazarides et al Ann Vasc Surg. 1997; 11: General vascular Midwinter et al Br J Surg. 1999; 86: D2 gastrectomyParikh et al Br J Surg. 1996; 83: ColorectalSagar et al Br J Surg ; 81:

POSSUMs in Colorectal Surgery Tekkis et al(GI)Dis Col Rect 2000, 43: Tekkis et alBr J Surg 2003, 90: Overpredicts young, fit, elective Underpredictselderly, emergency

CR-POSSUM Age Cardiac status BP Pulse Hb Urea Operation Peritoneal contamination Extent of malignancy Emergency / Elective PhysiologicalOperative Minimum risk of mortality = 0.27%

Practicalities Calculating POSSUM Calculate P-POSSUM and CR-POSSUM directly at Downloading POSSUM Download ACCESS 97 database from

Practicalities

Download POSSUM for use on Palm PDA and Pocket PC at

How the NHS has used last year's performance indicators Outcomes of Surgery ********** City Hospital was prompted by last year's clinical indicator on 'deaths following surgery' to investigate this issue and develop initiatives to ensure risks of death following surgery are as low as possible. A key development in Nottingham City Hospital's general surgery directorate has been the introduction of a robust risk assessment system called POSSUM (Physiological and Operative Severity Score for enumeration for Mortality and Morbidity). This is designed to quantify each patient's vulnerability by taking into account factors of their condition and the procedure they are to undergo. This accurate assessment allows doctors and nurses to design care packages which best meet their individual needs - patients with high POSSUM scores are targeted for higher levels of support and patients with medium scores are monitored more closely to ensure they do not deteriorate. The plan is to 'roll out' the system to other surgical directorates and POSSUM is clearly expected to improve the outcomes for more and more patients following surgery at *********City Hospital.

How the NHS has used last year's performance indicators clearly expected to improve the outcomes for more and more patients POSSUM

Government unveils hospital league tables David Batty Tuesday September 25, 2001 The Guardian

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P W D L F A W D L F A GD PTS Arsenal Chelsea Man Utd Charlton Newcastle Birm’ham Aston Villa Liverpool Fulham Tottenham South’ton Mid’brough Bolton Everton –5 32 Man City Blackburn Leicester Portsmouth Wolves Leeds Utd