Identification of the high risk emergency surgical patient: Which risk prediction model should be used?

Abstract

IntroductionNational guidance states that all patients having emergency surgery should have a mortality risk assessment calculated on admission so that the ‘high risk’ patient can receive the appropriate seniority and level of care. We aimed to assess if peri-operative risk scoring tools could accurately calculate mortality and morbidity risk.MethodsMortality risk scores for 86 consecutive emergency laparotomies, were calculated using pre-operative (ASA, Lee index) and post-operative (POSSUM, P-POSSUM and CR-POSSUM) risk calculation tools. Morbidity risk scores were calculated using the POSSUM predicted morbidity and compared against actual morbidity according to the Clavien–Dindo classification.ResultsThe actual mortality was 10.5%. The average predicted risk scores for all laparotomies were: ASA 26.5%, Lee Index 2.5%, POSSUM 29.5%, P-POSSUM 18.5%, CR-POSSUM 10.5%.Complications occurred following 67 laparotomies (78%). The majority (51%) of complications were classified as Clavien–Dindo grade 2–3 (non-life-threatening).Patients having a POSSUM morbidity risk of greater than 50% developed significantly more life-threatening complications (CD 4–5) compared with those who predicted less than or equal to 50% morbidity risk (P = 0.01).DiscussionPre-operative risk stratification remains a challenge because the Lee Index under-predicts and ASA over-predicts mortality risk. Post-operative risk scoring using the CR-POSSUM is more accurate and we suggest can be used to identify patients who require intensive care post-operatively.ConclusionsIn the absence of accurate risk scoring tools that can be used on admission to hospital it is not possible to reliably audit the achievement of national standards of care for the ‘high-risk’ patient.

Derivation and validation of a preoperative risk model for postoperative mortality (SAMPE model): An approach to care stratification

“…Some employ the same variables we selected[ 5 – 7 ] but have limited generalizability and are not easily applied at the bedside. Others, such as the POSSUM score, rely on multiple pre and intraoperative variables and have been shown to overestimate mortality in lower-risk groups [ 12 , 13 ].…”

Risk factors for mortality after emergency laparotomy: scoping systematic review

“…Several adjustments have been made to combat the overestimation of risk by the POSSUM score such as the Portsmouth modification. [7][8][9] More recently, a novel risk prediction calculator has been developed by the NELA network which is designed for EL. 10 The calculator is certainly specific and modern but is based on the definitions of comorbidities and factors collected for the older P-POSSUM calculator.…”

Development and internal validation of a novel risk adjustment model for adult patients undergoing emergency laparotomy surgery: the National Emergency Laparotomy Audit risk model

“…4e7 Various models are available to estimate the short-term risk of death after emergency bowel surgery, including: the Portsmouth Physiological and Operative Severity Score for the enumeration of Mortality and Morbidity (P-POSSUM) model, 8e12 the Biochemistry and Haematology Outcome Model (BHOM), 13 the Surgical Outcome Risk Tool (SORT), 14 and others. 3,15e24 Systematic reviews 25,26 of such models have identified substantial limitations in their design because they were often derived using small, single-site studies, were restricted to specific populations, or both. This makes it difficult to draw general conclusions about their performance.…”