Risk-adjusted analysis of surgeon performance: a 1-year study

Endoscopic Management of Malignant Colonic Obstruction

Advanced colorectal cancer can cause acute colonic obstruction, which is a life-threatening condition that requires emergency bowel decompression. Malignant colonic obstruction has traditionally been treated using emergency surgery, including primary resection or stoma formation. However, relatively high rates of complications, such as anastomosis site leakage, have been considered as major concerns for emergency surgery. Endoscopic management of malignant colonic obstruction using a self-expandable metal stent (SEMS) was introduced 20 years ago and it has been used as a first-line palliative treatment. However, endoscopic treatment of malignant colonic obstruction using SEMSs as a bridge to surgery remains controversial owing to short-term complications and longterm oncological outcomes. In this review, the current status of and recommendations for endoscopic management using SEMSs for malignant colonic obstruction will be discussed.

Low psoas muscle index is a poor prognostic factor for lower gastrointestinal perforation: a single-center retrospective cohort study

Background

Various body composition indices have been reported as prognostic factors for different cancers. However, whether body composition affects prognosis after lower gastrointestinal tract perforation requiring emergency surgery and multidisciplinary treatment has not been clarified. This study examined whether body composition evaluations that can be measured easily and quickly from computed tomography (CT) are useful for predicting prognosis.

Methods

Subjects comprised 64 patients diagnosed with perforation at final diagnosis after emergency surgery for a preoperative diagnosis of lower gastrointestinal tract perforation and penetration. They were divided into a survival group and a non-survival (in-hospital mortality) group and compared. Body composition indices (psoas muscle index (PMI); psoas muscle attenuation (PMA); subcutaneous adipose tissue index (SATI); visceral adipose tissue index (VATI); visceral-to-subcutaneous fat area ratio (VSR)) were measured from preoperative CT. Cross-sectional psoas muscle area at the level of the 3rd lumbar vertebra was quantified. Optimal cut-off values were calculated using receiver operating characteristic curve analysis. Poor prognostic factors were investigated from multivariate logistic regression analyses that included patient factors, perioperative factors, intraoperative factors, and body composition indices as explanatory variables.

Results

The cause of perforation was malignant disease in 12 cases (18.7%), and benign disease in 52 cases (81.2%). The most common cause was diverticulum of the large intestine. Emergency surgery for the 64 patients led to survival in 52 patients and death in 12 patients. On multivariate logistic regression analysis, independent predictors of poor prognosis were Sequential Organ Failure Assessment score (odds ratio 1.908; 95% confidence interval (CI) 1.235–3.681; P = 0.0020) and PMI (odds ratio 13.478; 95%CI 1.342–332.690; P = 0.0252). The cut-off PMI was 4.75 cm²/m² for males and 2.89 cm²/m² for females. Among survivors, duration of hospitalization was significantly longer in the low PMI group (29 days) than in the high PMI group (22 days, p = 0.0257).

Conclusions

PMI is easily determined from CT and allows rapid evaluation of prognosis following lower gastrointestinal perforation.

Effect of Surgical Expertise on Biomechanical Properties of Sutures After Abdominal Wall Closure

BACKGROUND

Despite preventive methods and careful surgical technique, surgical site infection and incisional hernias are of main concern after the closure of surgical incisions and keep haunting abdominal wall wound healing. The aim of this study is to find how surgical expertise level modifies biomechanical properties of sutures commonly used in abdominal wall fascial closure (polypropylene, polyglactin 910, polydioxanone).

MATERIALS AND METHODS

Surgery residents with different experience levels performed abdominal wall fascial closure in swine models with the previously mentioned suture materials. A standardized technique was used. Sutures were removed, and a tensile stress test was performed on the removed sutures. A total of 81 abdominal fascial closures were achieved. Time, extension, maximum tensile force (F_tmax), and maximum stress were measured and analyzed.

RESULTS

The results of the polydioxanone stress test present a trend in three variables: extension, tensile force, and stress. The trend shows higher medians in the expert group and lower medians in the novice group. While using polypropylene sutures, medians in the expert group are the highest; however, a trend is not observed. Polyglactin 910 sutures have nonspecific behavior among the different experience groups and variables. Polypropylene is the material with the lowest F_tmax tested and fails at 42.64 (IQR 40.98-44.89) N. Regarding the elastic properties of the material, polyglactin demonstrates the least extension of all sutures tested, with a 14 (IQR 13.33-14.83) mm extension. This study demonstrates that polydioxanone has a superior F_tmax compared with polypropylene and has a superior extension at failure properties compared with polyglactin, confirming that polydioxanone could be the suture of choice used for abdominal wall fascial closure.

CONCLUSIONS

Study results do not show statistically significant differences regarding the impact of the experience level of different general surgery residents in the biomechanical properties of sutures used in abdominal wall fascial closure.

Stent as bridge to surgery for left-sided malignant colonic obstruction reduces adverse events and stoma rate compared with emergency surgery: results of a systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

Twenty years after the first description of the technique, the debate is still open on the role of self-expandable metallic stent (SEMS) placement as a bridge to elective surgery for symptomatic left-sided malignant colonic obstruction. The aim was to compare morbidity rates after colonic stenting bridge to surgery (SBTS) versus emergency surgery (ES) for left-sided malignant obstruction.

METHODS

We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) on SBTS or ES for acute symptomatic malignant left-sided large bowel obstruction. The primary outcome was overall morbidity within 60 days after surgery.

RESULTS

The meta-analysis included 8 RCTs and 497 patients. Overall mortality within 60 days after surgery was 9.6% in SBTS-treated patients and 9.9% in ES-treated patients (relative risk [RR], 0.99; P = .97). Overall morbidity within 60 days after surgery was 33.9% in SBTS-treated patients and 51.2% in ES-treated patients (RR, 0.59; P = .023). The temporary stoma rate was 33.9% after SBTS and 51.4% after ES (RR, 0.67; P < .001). The permanent stoma rate was 22.2% after SBTS and 35.2% after ES (RR, 0.66; P = .003). Primary anastomosis was successful in 70.0% of SBTS-treated patients and 54.1% of ES-treated patients (RR, 1.29; P = .043).

CONCLUSIONS

SBTS was associated with lower short-term overall morbidity and lower rates of temporary and permanent stoma. Depending on multiple factors such as local expertise, clinical status including level of obstruction, and level of certainty of diagnosis, SBTS does offer some advantages with less risk than ES for left-sided malignant colonic obstruction in the short term.

Prediction of mortality in patients with colorectal perforation based on routinely available parameters: a retrospective study

INTRODUCTION

Even after surgery and intensive postoperative management, the mortality rate associated with colorectal perforation is high. Identification of mortality markers using routinely available preoperative parameters is important.

METHODS

We enrolled consecutive patients with colorectal perforation who underwent operations from January 2010 to January 2015. We divided them into a mortality and survivor group and compared clinical characteristics between the two groups. Additionally, we compared the mortality rate between different etiologies: malignant versus benign and diverticular versus nondiverticular. We used the χ (2) and Mann-Whitney U tests and a logistic regression model to identify factors associated with mortality.

RESULTS

We enrolled 108 patients, and 52 (48 %) were male. The mean age at surgery was 71 ± 13 years. The postoperative mortality rate was 12 % (13 patients). Multivariate logistic regression analysis showed that a high patient age (odds ratio [OR], 1.09; 95 % confidence interval [CI], 1.020-1.181) and low preoperative systolic blood pressure (OR, 0.98; 95 % CI, 0.953-0.999) were independent risk factors for mortality in patients with colorectal perforation. In the subgroup analysis, there was no significant difference between the malignant and benign group (11.8 % vs. 23.9 %, respectively; p = 0.970), while the diverticular group had a significantly lower mortality rate than the nondiverticular group (2.6 % vs. 17.1 %, respectively; p = 0.027).

CONCLUSIONS

Older patients and patients with low preoperative blood pressure had a high risk of mortality associated with colorectal perforation. For such patients, operations and postoperative management should be performed carefully.

POSSUM and p-POSSUM overestimate morbidity and mortality in laparoscopic bariatric surgery

BACKGROUND

Despite their wide use in surgical audit, the application of the Physiologic and Operative Severity Score for the enUmeration of Mortality and Morbidity (POSSUM) and the Portsmouth predictor of mortality (p-POSSUM) in bariatric surgery has been limited. The aim of this study was to evaluate the usefulness of POSSUM and p-POSSUM in bariatric comparative audit.

METHODS

Data were retrospectively collected on consecutive patients who underwent laparoscopic gastric by-pass (LRYGB) and sleeve gastrectomy (SG) at a teaching institute. POSSUM and p-POSSUM equations were applied. The observed to expected ratios for morbidity and mortality were calculated. A Student's t test was performed to assess if a relationship could be found between the observed and the predicted outcomes.

RESULTS

Between 2008 and 2013, 504 patients (370 female) with a mean (range) age of 46 (17-69) years underwent LRYGB (n = 383) and SG (n = 121). The operative morbidity was 10.9% and mortality was .2%. POSSUM overpredicted morbidity (30.56%), and no relationship between morbidity risk and the development of complications was found (P = .152). There was a grouping of patients in the low-risk mortality groups for both POSSUM and p-POSSUM. Both equations overpredicted mortality (5.95% and 1.62%, respectively).

CONCLUSION

Both POSSUM and p-POSSUM equations overpredicted morbidity and mortality in this only study in the literature of modern bariatric practice that employed a large representative patient sample receiving the commonest procedures. A multicenter study is needed to address the low incidence of events and enable modification of those equations for use in bariatric surgical audit.

Risk stratification tools for predicting morbidity and mortality in adult patients undergoing major surgery: qualitative systematic review

Risk stratification is essential for both clinical risk prediction and comparative audit. There are a variety of risk stratification tools available for use in major noncardiac surgery, but their discrimination and calibration have not previously been systematically reviewed in heterogeneous patient cohorts.Embase, MEDLINE, and Web of Science were searched for studies published between January 1, 1980 and August 6, 2011 in adult patients undergoing major noncardiac, nonneurological surgery. Twenty-seven studies evaluating 34 risk stratification tools were identified which met inclusion criteria. The Portsmouth-Physiology and Operative Severity Score for the enUmeration of Mortality and the Surgical Risk Scale were demonstrated to be the most consistently accurate tools that have been validated in multiple studies; however, both have limitations. Future work should focus on further evaluation of these and other parsimonious risk predictors, including validation in international cohorts. There is also a need for studies examining the impact that the use of these tools has on clinical decision making and patient outcome.

Surgical training on rectal cancer surgery: do supervised senior residents differ from consultants in outcomes?

INTRODUCTION

The present work is a comparative study to investigate the independent effect of tutored senior residents on rectal cancer surgery in an academic university hospital. The variable "surgeon" is held to be a major determinant of outcome following total mesorectal excision (TME) for rectal cancer.

OBJECTIVE

We hypothesized that TME can be tutored to senior surgical residents without compromising surgical and oncological outcomes.

METHODS

Demographics, preoperative characteristics, and surgical data from consecutive patients undergoing elective TME in an academic center over the last decade were retrospectively reviewed from a prospectively collected database. Outcomes were compared in the two cohorts by a principal surgeon (senior resident or staff) and supervised in all cases by a senior colorectal consultant. Association of outcome variables with the type of surgeon was determined by univariate and multivariate analyses and results were corrected by tumor's height.

RESULTS

A total of 230 patients were treated over the study period; 136 (59 %) surgeries were performed by staff surgeons (group S) and 94 (41 %) by residents (group R). Both groups were comparable except for distance to anal verge; staff surgeons operated on lower tumors and performed a high percentage of coloanal anastomosis. There were no statistical differences between groups in terms of surgical and oncological outcomes when tumors were located over 7 cm from the anal verge.

CONCLUSIONS

Rectal surgery can be performed by senior residents with equal results to staff surgeons when there is direct supervision by a senior consultant and when the tumor is located in the mid-upper rectum (>7 cm from the anal verge). For lower tumors, a careful selection must be made as the operation may require a higher level of training.

Safe surgery: how accurate are we at predicting intra-operative blood loss?

INTRODUCTION

Preoperative estimation of intra-operative blood loss by both anaesthetist and operating surgeon is a criterion of the World Health Organization's surgical safety checklist. The checklist requires specific preoperative planning when anticipated blood loss is greater than 500 mL. The aim of this study was to assess the accuracy of surgeons and anaesthetists at predicting intra-operative blood loss.

METHODS

A 6-week prospective study of intermediate and major operations in an academic medical centre was performed. An independent observer interviewed surgical and anaesthetic consultants and registrars, preoperatively asking each to predict expected blood loss in millilitre. Intra-operative blood loss was measured and compared with these predictions. Parameters including the use of anticoagulation and anti-platelet therapy as well as intra-operative hypothermia and hypotension were recorded.

RESULTS

One hundred sixty-eight operations were included in the study, including 142 elective and 26 emergency operations. Blood loss was predicted to within 500 mL of measured blood loss in 89% of cases. Consultant surgeons tended to underestimate blood loss, doing so in 43% of all cases, while consultant anaesthetists were more likely to overestimate (60% of all operations). Twelve patients (7%) had underestimation of blood loss of more than 500 mL by both surgeon and anaesthetist. Thirty per cent (n = 6/20) of patients requiring transfusion of a blood product within 24 hours of surgery had blood loss underestimated by more than 500 mL by both surgeon and anaesthetist. There was no significant difference in prediction between patients on anti-platelet or anticoagulation therapy preoperatively and those not on the said therapies.

CONCLUSION

Predicted intra-operative blood loss was within 500 mL of measured blood loss in 89% of operations. In 30% of patients who ultimately receive a blood transfusion, both the surgeon and anaesthetist significantly underestimate the risk of blood loss by greater than 500 mL. Theatre staff must be aware that 1 in 14 patients undergoing intermediate or major surgery will have an unexpected blood loss exceeding 500 mL and so robust policies to identify and manage such circumstances should be in place to improve patient safety.

Can the Surgical Apgar Score predict morbidity and mortality in general orthopaedic surgery?

PURPOSE

The Surgical Apgar Score (SAS) is a simple tally based on intra-operative heart rate, blood pressure and blood loss; it predicts 30-day major postoperative complications and mortality in different surgical fields, but no validation has been performed in general orthopaedic surgery.

METHODS

A prospective assessment of the SAS in 723 consecutive patients undergoing major and intermediate orthopaedic procedures was performed in an 18-month period. The SAS was calculated immediately after surgery, and the occurrence of major complications or death was registered within a 30-day follow-up.

RESULTS

Thirty-seven patients had ≥1 complication (5.12 %). The complication rate did not augment as the score decreased (SAS 9-10 = 6.56 %; SAS 7-8 = 2.62 %; SAS 5-6 = 7.21 %; SAS ≤4 = 10.2 %), the relative risk did not augment as the score decreased and the likelihood ratio did not increase with decreasing SAS values, except in the subgroup of patients undergoing spine surgery. The C-statistic was 0.59 (95 % confidence interval 0.48-0.69), a weak discriminatory value. Using a threshold of 7 to define high-risk and low-risk patients, the SAS allowed risk stratification only for spine surgery.

CONCLUSIONS

The SAS does not predict 30-day major complications and death in patients undergoing general orthopaedic surgery, but it is useful in the subgroup of patients undergoing spine surgery.

Risk factors for mortality in major digestive surgery in the elderly: a multicenter prospective study

OBJECTIVE

To identify the mortality risk factors of elderly patients (≥65 years old) during major digestive surgery, as defined according to the complexity of the operation.

BACKGROUND

In the aging populations of developed countries, the incidence rate of major digestive surgery is currently on the rise and is associated with a high mortality rate. Consequently, validated indicators must be developed to improve elderly patients' surgical care and outcomes.

METHODS

We acquired data from a multicenter prospective cohort that included 3322 consecutive patients undergoing major digestive surgery across 47 different facilities. We assessed 27 pre-, intra-, and postoperative demographic and clinical variables. A multivariate analysis was used to identify the independent risk factors of mortality in elderly patients (n = 1796). Young patients were used as a control group, and the end-point was defined as 30-day postoperative mortality.

RESULTS

In the entire cohort, postoperative mortality increased significantly among patients aged 65-74 years, and an age ≥65 years was by itself an independent risk factor for mortality (odds ratio [OR], 2.21; 95% confidence interval [CI], 1.36-3.59; P = 0.001). The mortality rate among elderly patients was 10.6%. Six independent risk factors of mortality were characteristic of the elderly patients: age ≥85 years (OR, 2.62; 95% CI, 1.08-6.31; P = 0.032), emergency (OR, 3.42; 95% CI, 1.67-6.99; P = 0.001), anemia (OR, 1.80; 95% CI, 1.02-3.17; P = 0.041), white cell count > 10,000/mm³ (OR, 1.90; 95% CI, 1.08-3.35; P = 0.024), ASA class IV (OR, 9.86; 95% CI, 1.77-54.7; P = 0.009) and a palliative cancer operation (OR, 4.03; 95% CI, 1.99-8.19; P < 0.001).

CONCLUSION

Characterization of independent validated risk indicators for mortality in elderly patients undergoing major digestive surgery is essential and may lead to an efficient specific workup, which constitutes a necessary step to developing a dedicated score for elderly patients.

Usefulness of POSSUM physiological score for the estimation of morbidity and mortality risk after elective abdominal aortic aneurysm repair in Japan

BACKGROUND

The Physiological and Operative Severity Score for enUmeration of Mortality and morbidity (POSSUM), which consists of a physiological score (PS) and an operative severity score, is useful in determining the risk profile for patients with abdominal aortic aneurysms in Western countries, but no information is available on the use of this method in Japan.

METHODS AND RESULTS

A retrospective cohort study involving 225 patients was performed, and the prognostic factors for morbidity and in-hospital mortality including POSSUM were investigated. The morbidity rate was 26%. On univariate analysis age, renal disease, hemoglobin, albumin, operation time, blood loss and PS were significantly different. On multivariate analysis PS was significantly different. Using receiver operating characteristic (ROC) analysis, PS had an area under the curve (AUC) of 0.712 and the best cut-off point was 18. The in-hospital mortality rate was 2.2%. On univariate analysis renal disease, albumin and PS were significantly different, and on multivariate analysis PS was significantly different. On ROC analysis PS had an AUC of 0.921 and the best cut-off point was 22.

CONCLUSIONS

PS was the only independent risk factor for morbidity and in-hospital mortality. Further studies may be required to develop a risk-scoring system.

A systematic review of POSSUM and its related models as predictors of post-operative mortality and morbidity in patients undergoing surgery for colorectal cancer

INTRODUCTION

The Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) model and its Portsmouth (P-POSSUM) and colorectal (CR-POSSUM) modifications are used extensively to predict and audit post-operative mortality and morbidity. This aim of this systematic review was to assess the predictive value of the POSSUM models in colorectal cancer surgery.

METHODS

Major electronic databases, including Medline, Embase, Cochrane Library and Pubmed were searched for original studies published between 1991 and 2010. Two independent reviewers assessed each study against inclusion and exclusion criteria. All data was specific to colorectal cancer surgery. Predictive value was assessed by calculating observed to expected (O/E) ratios.

RESULTS

Nineteen studies were included in final review. The mortality analysis included ten studies (4,799 patients) on POSSUM, 17 studies (6,576 patients) on P-POSSUM and 14 studies (5,230 patients) on CR-POSSUM. Weighted O/E ratios for mortality were 0.31 (CI 0.31-0.32) for POSSUM, 0.90 (CI 0.88-0.92) for P-POSSUM and 0.64 (CI 0.63-0.65) for CR-POSSUM. The morbidity analysis included four studies (768 patients) on POSSUM with a weighted O/E ratio of 0.96 (CI 0.94-0.98).

CONCLUSIONS

P-POSSUM was the most accurate model for predicting post-operative mortality after colorectal cancer surgery. The original POSSUM model was accurate in predicting post-operative complications.

Validity of the orthopedic POSSUM scoring system for the assessment of postoperative mortality in patients with pressure ulcers

In the treatment of pressure ulcers, assessment of systemic problems is an important yet difficult step in selecting either conservative or surgical therapeutic intervention. The surgical auditing system called the Physiological and Operative Severity Score for enUmeration of Mortality and Morbidity (POSSUM) and its orthopedic version (O-POSSUM), which gives a predictive mortality rate for the first 30 postoperative days, may be useful for assessing systemic status, but have yet to be sufficiently validated for patients with pressure ulcers. To assess the validity of POSSUM and O-POSSUM, 71 procedures on 50 cases were retrospectively statistically analyzed using receiver operating characteristic curves and goodness-of-fitness testing with the Hosmer-Lemeshow chi(2) test for logistic regression modeling. POSSUM and O-POSSUM showed satisfactory discriminatory power in receiver operating curve analysis. The validity of the values obtained by POSSUM and O-POSSUM was also confirmed. O-POSSUM was superior to POSSUM in both analyses. O-POSSUM is useful in assessing the systemic status of patients with pressure ulcers. Some patients with pressure ulcers show extreme systemic conditions. Assessment of systemic status with O-POSSUM contributes to daily clinical practice and future studies of treatments for pressure ulcers.

Evaluation of POSSUM for patients undergoing pancreatoduodenectomy

Background

Comparison of operative morbidity rates after pancreatoduodenectomy between units may be misleading because it does not take into account the physiological variable of the condition of the patients. The aim of the present study was to evaluate the Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity (POSSUM) for pancreatoduodenectomy patients and to look for risk factors associated with morbidity in a high-volume center.

Methods

Between January 1993 and April 2006, 652 patients underwent a pancreatoduodenectomy, 502 of them for malignant disease. POSSUM performance was evaluated by assessing the “goodness-of-fit” with the linear analysis method.

Results

Overall, 332 of the 652 patients (50.9%) had one or more complication after pancreatoduodenectomy, and 9 patients (1.4%) died. POSSUM had a significant lack of fit using goodness-of-fit analysis. In multivariate analysis, one statistically significant factor associated with morbidity and not incorporated in POSSUM (P < 0.05) was identified: ampulla of Vater adenocarcinoma (OR = 1.73, 95% CI: 1.07–2.80).

Conclusions

Overall, there is a lack of calibration of POSSUM among patients who undergo pancreatoduodenectomy.

Orthopaedic POSSUM scoring system: An assessment of the risk of debridement in patients with pressure sores

We hypothesised that the implementation of a validated method of audit, the Physiological and Operative Severity Score for enUmeration of Mortality and morbidity (POSSUM), would be useful in the evaluation of the risks of debridement in bedridden patients with pressure ulcers. With the orthopaedic version of POSSUM (O-POSSUM), physiological data and an operative profile are scored to predict mortality for 30 days postoperatively. Fourteen cases were analysed retrospectively. The difference in predicted mortality was compared with those who died and those who survived. The mean (SD) predicted mortality among those who died was 47 (16)%, and among those who lived was 18 (14)%. Those who died were classified as a relatively high risk group, and the values differed significantly (p=0.01). O-POSSUM may be helpful in audit.

Risk adjustment is crucial in comparing outcomes of various surgical modalities in patients with ileal perforation

Background

Using crude mortality and morbidity rates for comparing outcomes can be misleading. The aim of the present study was to compare the outcome of various surgical modalities without and with risk adjustment using Physiologic and Operative Severity Scoring for the enUmeration of Mortality and morbidity (POSSUM) score in cases of ileal perforations.

Methods

Prospective study on 125 patients of ileal perforations. Resection anastamosis (Group I) was done in 38 patients, primary repair (Group II) in 42 patients and 45 patients had an ileostomy (Group III). The disease severity was assessed in all patients using POSSUM score. The odds of death without and with risk adjustment using POSSUM mortality score were calculated for all groups

Results

Seventeen patients (14%) patients died and 99 (79%) developed postoperative complications. Using crude mortality rates Group I appeared to be the best treatment option with only 2 (5%) deaths followed by Group II with 5 (12%) deaths where as Group III had the worst outcome with 10 deaths (22%). However, Group III (ileostomy) patients had higher mean POSSUM mortality and morbidity score (55.55%, 91.33%) than Group I (28%, 75.26%) and Group II (27%, 73.59%). Taking Group I as the reference (odds ratio, OR1) odds of death were greatest in Group III (OR 5.14, p = 0.043) followed by Group II (OR 2.43, p = 0.306). With risk adjustment using POSSUM mortality score the odds of death decreased in Group III (OR 1.16 p = 0.875). For the whole group, there was a significant association between the POSSUM score and postoperative complications and deaths. Mean POSSUM mortality and morbidity score of those who died (63.40 vs.33.68, p = 0.001) and developed complications (66.32 vs.84.20, p = 0.001) was significantly higher. For every percent increase in severity score the risk of postoperative complications and death increased by 1.10 (p = 0.001) and1.06 (p = 0.001) respectively.

Conclusion

Despite ileostomy patients having highest crude mortality and complication rates, after risk adjustment it was equally safe. Severity of the disease rather than the surgical option had a significant impact on the outcome in patients with ileal perforations.

Evaluation of POSSUM scoring system in the treatment of osteoporotic fracture of the hip in elder patients

OBJECTIVE

To evaluate the applicability of the modified physiological and operative severity score for enumeration of mortality and morbidity (POSSUM) scoring system in predicting mortality in the patients undergoing hip joint arthroplasty.

METHODS

A total of 295 patients with hip fractures were analyzed using the modified POSSUM surgical scoring system. The mean ages of the patients were 66.59 years in the complicative group, 62.28 years in noncomplicative group, 77.89 years in the death group and 63.25 years in the living group, respectively. The comparisons between the observed and predicted morbidity, between the observed and predicted mortality were made within 30 days after operation.

RESULTS

The average physiological scores and operative severity scores was 18.96+/-4.83 and 13.47+/-2.01 in complicative group, while 15.65+/-3.66 and 11.74+/-2.26 in noncomplicative group (P less than 0.05). The average physiological scores and operative severity scores was 25.56+/-3.78 and 14.22+/-0.67 in death group, while 16.46+/-4.09 and 12.25+/-2.33 in living group (P less than 0.05). Though POSSUM scoring system over-predicted the overall risk of death, its estimate was very close in the high risk groups (larger than 10% ). There was perfect consistence between the observed and the predicted morbidity as calculated by published predictor equation for morbidity, and consistence for mortality in the high risk band.

CONCLUSIONS

Modified POSSUM scoring system may be used to predict the morbidity in patients with hip fracture. Furthermore, POSSUM scoring system overpredicts the overall risk of death, but its estimate is close to the actual data in the high risk band (larger than 10%).

Comparison of outcome of POSSUM, p-POSSUM, and cr-POSSUM scoring after elective resection of the sigmoid colon for carcinoma or complicated diverticular disease

OBJECTIVE

To compare POSSUM, p-POSSUM, and cr-POSSUM-predicted mortalities with the observed postoperative mortality in patients undergoing elective sigmoid colectomy for diverticular disease (n=121) or carcinoma (n=120).

MATERIAL AND METHODS

The physiologic and operative severity score for the enumeration of mortality and morbidity (POSSUM) was used to identify patient- or disease-related risk factors and to calculate expected mortalities.

RESULTS

Patients with carcinoma had significantly higher POSSUM scores, but the observed mortality (1.7%) was lower than that in the diverticular disease group (3.3%). In the carcinoma group, mortality was over-predicted by all the POSSUM systems. In diverticular disease, POSSUM over-predicted mortality while p-POSSUM and cr-POSSUM under-predicted mortality. In the whole group, POSSUM over-predicted mortality. P-POSSUM and cr-POSSUM predicted mortality accurately: observed:expected (O:E) ratio 0.83. Replacing the score for malignancy with a minimum score of 1 gave overall O:E ratios of 0.37 (POSSUM), 1.04 (p-POSSUM), and 0.93 (cr-POSSUM).

CONCLUSIONS

In a group of patients who underwent elective resection of the sigmoid colon for carcinoma or diverticular disease, postoperative mortality was predicted accurately by p-Possum and cr-POSSUM, especially when used without a score for malignancy. None of the POSSUM scores were predictive of disease-specific mortality.

Prospective comparison of POSSUM and P-POSSUM with clinical assessment of mortality following emergency surgery

BACKGROUND

Tools to accurately estimate the risk of death following emergency surgery are useful adjuncts to informed consent and clinical decisions. This prospective study compared the Physiological and Operative Severity Score for the Enumeration of Mortality and Morbidity (POSSUM) and Portsmouth POSSUM (P-POSSUM) scoring systems with clinical judgement in predicting mortality from emergency surgery.

METHODS

Data were collected prospectively from 163 patients. Details of the physiological and operative severity scores were recorded for POSSUM and P-POSSUM. The estimates of both the surgeon and anaesthetist for 30-day and in-hospital mortality were also recorded pre-operatively. The accuracies of the four predictions were then compared with actual mortalities using linear and exponential analysis and receiver operator characteristics (ROC).

RESULTS

P-POSSUM gave the most accurate prediction of 30-day mortality using linear analysis [observed to expected ratio (O : E) = 1.0]. POSSUM gave the most accurate prediction using exponential analysis (O : E = 1.15). Clinical judgement of mortality from both operating surgeons and anaesthetists compared favourably with the scoring systems for 30-day mortality (O : E = 0.83 and O : E = 0.93, respectively). ROC analyses showed both clinical judgement and the POSSUM scores to be good predictors of 30-day mortality with area under the curve values (AUC) of 0.903, 0.907, 0.946 and 0.940 for surgeons, anaesthetists, POSSUM and P-POSSUM respectively.

CONCLUSIONS

POSSUM and P-POSSUM appear to be useful indicators for the prediction of mortality. Clinical judgement compares strongly with scoring systems in predicting post-operative mortality, but may underestimate mortality in very high-risk patients with more than 90% mortality.

Outcomes following a shortage of high dependency unit beds for surgical patients

In an environment of resource rationing there are numerous patients who are unable to be admitted to a high-dependency unit (HDU) postoperatively despite the belief that this is the optimal discharge destination for them from the recovery room. It is unknown if this is associated with an increase in adverse outcomes. We performed an observational study, over a two-month period, comparing outcomes between patients who were admitted to HDU postoperatively and patients who, although an HDU bed was preferred, were discharged from the recovery room to the general ward due to an unavailability of HDU beds. Our primary outcome variable was hospital length-of-stay. We found an almost twofold increase in hospital length-of-stay in the group of patients admitted to the HDU. ASA IV patients were more likely to be admitted to HDU. However, the increased length-of-stay in the HDU group persisted even after stratifying patients according to ASA status. There was no difference between groups in all other baseline demographic variables, including POSSUM score, which is used as a predictor of postoperative morbidity and mortality. We believe that the most likely explanation for our findings is that the baseline risk between groups is, in fact, subtly different. This is not detected by preoperative scoring systems. However, clinical judgement in the recovery room appears to select a group of patients for HDU admission who subsequently have a slower postoperative recovery, despite no measurable increase in complication rate. That there was no increase in adverse events in the group of patients unable to be admitted to HDU due to a lack of bed availability suggests that current clinical judgement in a resource-rationed environment is functioning adequately, but the study was not powered to detect such a difference.

Mortality after acute surgery for complications of diverticular disease of the sigmoid colon is almost exclusively due to patient related factors

OBJECTIVE

Auditing the outcome of surgery for complicated diverticulitis of the sigmoid colon is difficult. A comparison of studies is hardly possible because risk factors both in terms of the severity of diverticulitis and patient-related risk factors are neither well described nor standardized. The purpose of this study was to define morbidity and mortality of primary surgery for acute complications of diverticular disease of the sigmoid colon and to identify the relation between risk factors and morbidity and mortality.

METHODS

In a prospective computerized morbidity and mortality registration from 1990 to 2002, 114 patients, who underwent surgery on an acute or urgent base for acute complications of diverticular disease of the sigmoid colon, were identified. In all patients the POSSUM score was calculated. To audit mortality rates a POSSUM based scoring system was introduced.

RESULTS

Mortality was 16.7%, and morbidity 71.1%. Higher morbidity rates were significantly related to a higher POSSUM physiological score (P = 0.012) and to older age (P < 0.001). Higher mortality rates also were significantly related to a higher POSSUM physiological score (P < 0.001) and older age (P = 0.003). Patients who died had significantly more sepsis (P < 0.001), multiple organ failure (P = 0.027), cardiac (P < 0.001) and pulmonary (P = 0.013) complications. Gender, operation indication and type of neither surgery nor surgeon had a significant relation with morbidity or mortality.

CONCLUSION

Surgery for acute complications of diverticular disease of the sigmoid colon carries a high morbidity rate and a substantial mortality rate. The majority of deceased patients had severe comorbidity. Post-operative mortality and morbidity are to a large extent driven by patient related factors. Elevated physiological severity scores and a lack of peri-operative management failures express this in the majority of deceased patients.

Risk-adjustment in hepatobiliarypancreatic surgery

AIM: The present study evaluates the performance of the POSSUM, the American Society of Anesthetists (ASA), APACHE and Childs classification in predicting mortality and morbidity in hepatopancreaticobiliary (HPB) surgery. We describe especially the limitations and advantages of risk in stratifying the patients.

METHODS: We investigated 177 randomly chosen patients undergoing elective complex HPB surgery in a single institution with a total of 71 pre-operative and intra-operative risk factors. Primary endpoint was in-hospital mortality and morbidity. Ordered logistic regression analysis was used to identify individual predictors of operative morbidity and mortality.

RESULTS: The operative mortality in the series was 3.95%. This compared well with the p-POSSUM and APACHE predicted mortality of 4.31% and 4.29% respectively. Post-operative complications amounted to 45% with 24 (13.6%) patients having a major adverse event. On multivariate analysis the pre-operative POSSUM physiological score (OR = 1.18, P = 0.009) was superior in predicting complications compared to the ASA (P = 0.108), APACHE (P = 0.117) or Childs classification (P = 0.136). In addition, serum sodium, creatinine, international normalized ratio (INR), pulse rate, and intra-operative blood loss were independent risk factors. A combination of the POSSUM variables and INR offered the optimal combination of risk factors for risk prognostication in HPB surgery.

CONCLUSION: Morbidity for elective HPB surgery can be accurately predicted and applied in everyday surgical practice as an adjunct in the process of informed consent and for effective allocation of resources for intensive and high-dependency care facilities.

Predicting postoperative morbidity by clinical assessment

BACKGROUND

The aim of this study was to determine the accuracy of prediction of the surgeon's 'gut-feeling' in estimating postoperative outcome.

METHODS

A prospective series of 1077 consecutive patients undergoing major hepatobiliary or gastrointestinal surgery were studied. Patients having elective (n = 827) and emergency (n = 250) procedures were included. The surgeon predicted the development of postoperative complications immediately after completion of surgery on a scale from 0 to 100 percent. These predictions were compared with the actual outcome and with predictions made using the Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM). The Portsmouth predictor equation (P-POSSUM) was applied for the estimation of mortality.

RESULTS

The observed morbidity and mortality rates were 29.5 and 3.4 percent respectively. POSSUM predicted a morbidity rate of 46.4 percent and P-POSSUM a mortality rate of 6.9 percent. The surgeon's gut-feeling was more accurate in the prediction of morbidity at 32.1 percent. On the basis of gut-feeling, surgeons overpredicted morbidity in elective surgery, but underestimated the risk of complications in the emergency setting. The (P)-POSSUM scoring system overpredicted morbidity and mortality for elective and emergency operations.

CONCLUSION

The surgeon's gut-feeling is a good predictor of postoperative outcome, especially after elective surgery. (P)-POSSUM overpredicted morbidity and mortality in this series of major gastrointestinal and hepatobiliary operations.

Development of a dedicated risk-adjustment scoring system for colorectal surgery (colorectal POSSUM)

BACKGROUND

The aim of the study was to develop a dedicated colorectal Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (CR-POSSUM) equation for predicting operative mortality, and to compare its performance with the Portsmouth (P)-POSSUM model.

METHODS

Data were collected prospectively from 6883 patients undergoing colorectal surgery in 15 UK hospitals between 1993 and 2001. After excluding missing data and 93 patients who did not satisfy the inclusion criteria, 4632 patients (68.2 per cent) underwent elective surgery and 2107 had an emergency operation (31.0 per cent); 2437 operations (35.9 per cent) for malignant and 4267 (62.8 per cent) for non-malignant diseases were scored. Stepwise logistic regression analysis was used to develop an age-adjusted POSSUM model and a dedicated CR-POSSUM model. A 60:40 per cent split-sample validation technique was adopted for model development and testing. Observed and expected mortality rates were compared.

RESULTS

The operative mortality rate for the series was 5.7 per cent (387 of 6790 patients) (elective operations 2.8 per cent; emergency surgery 12.0 per cent). The CR-POSSUM, age-adjusted POSSUM and P-POSSUM models had similar areas under the receiver-operator characteristic curves. Model calibration was similar for CR-POSSUM and age-adjusted POSSUM models, and superior to that for the P-POSSUM model. The CR-POSSUM model offered the best overall accuracy, with an observed : expected ratio of 1.000, 0.998 and 0.911 respectively (test population).

CONCLUSION

The CR-POSSUM model provided an accurate predictor of operative mortality. External validation is required in hospitals different from those in which the model was developed.

Safe laparoscopic surgery in the elderly

BACKGROUND

The elderly are more prone to complications of surgery because of comorbidity, and they may benefit most from a minimally invasive approach. This study was intended to evaluate the safety of the use of a laparoscopic approach for emergency and elective surgery in elderly patients.

METHODS

From January 2000 to June 2001, all patients over 75 years of age who underwent a procedure that began laparoscopically were included. Physiologic and operative scores according to the POSSUM scoring system were recorded. These were then used to calculate predicted morbidity and mortality by both the POSSUM and P-POSSUM systems. Predicted outcomes were compared with actual outcomes.

RESULTS

One hundred sixty-two patients with a mean age of 80 years were included; 52% were emergency cases. The overall morbidity was 14.5% and the mortality rate was 1.8%. Fourteen procedures (8.4%), all emergencies, were converted. Both mortality and morbidity rates were lower than the predicted values (P = 0.001 and P = 0.0001, respectively).

CONCLUSIONS

A laparoscopic approach can be used safely in an elderly population undergoing surgery in a daily practice for miscellaneous conditions, whether elective or emergency operations.

Are postoperative complications genetically determined by TNF-β NcoI gene polymorphism?

BACKGROUND

Postoperative infectious complications are the leading causes for postoperative sepsis. In severe sepsis, tumor necrosis factor-beta (TNF-beta) NcoI polymorphism was associated with increased mortality. Therefore, the aim of this study was to determine whether the biallelic NcoI polymorphism within the TNF locus is associated with the development of postoperative complications.

METHODS

One hundred sixty patients were included in this prospective observation study. Patients undergoing major gastrointestinal surgery, such as esophagectomy, gastrectomy, Whipple operation, major liver resection, or colon resection were included. Patients were monitored during the clinical course, and postoperative complications, divided into severe and minor complications, were documented. The NcoI restriction fragment length polymorphism of the TNF-beta gene was determined by polymerase chain reaction; gene expression as well as complications were correlated.

RESULTS

The patients' genotype distribution and demographic characteristics were comparable within the different groups of operations. Patients with the heterozygous genotype TNF-beta1/beta2 had a 1.6-fold higher relative risk for developing complications. If patients with the homozygous genotype TNF-beta2 developed a complication, they had a 1.5-fold higher relative risk for severe complications. Furthermore, the mortality of patients with postoperative sepsis who were homozygous for the genotype TNF-beta2 was significantly elevated.

CONCLUSIONS

The TNF-beta NcoI polymorphism influences the development of postoperative complications. While the genotype TNF-beta1/beta2 has a higher risk for developing complications in general, the TNF-beta2/beta2 genotype is associated with more severe complications and mortality from sepsis.

Risk-adjusted prediction of operative mortality in oesophagogastric surgery with O-POSSUM

Introduction

The present study was designed to develop a dedicated oesophagogastric model for the prediction of risk-adjusted postoperative mortality in upper gastrointestinal surgery (O-POSSUM).

Methods

Using 1042 patients undergoing oesophageal (n = 538) or gastric (n = 504) surgery between 1994 and 2000 the Portsmouth predictor equation for mortality (P-POSSUM) scoring system was compared with a standard logistic regression O-POSSUM model and a multilevel O-POSSUM model using the following independent factors: age, physiological status, mode of surgery, type of surgery and histological stage.

Results

The overall mortality rate was 12·0 per cent (elective mortality rate 9·4 per cent and emergency mortality rate 26·9 per cent). P-POSSUM overpredicted mortality (14·5 per cent), particularly in the elective group of patients. The multilevel model offered higher discrimination than the single-level O-POSSUM and P-POSSUM models (area under receiver–operator characteristic curve 79·7 versus 74·6 and 74·3 per cent). When observed to expected outcomes were evaluated, the multilevel O-POSSUM model was found to offer better calibration (Hosmer–Lemeshow χ2 statistic 10·15 versus 10·52 and 28·80).

Conclusion

The multilevel O-POSSUM model provided an accurate risk-adjusted prediction of death from oesophageal and gastric surgery for individual patients. In conjunction with a multidisciplinary approach to patient management, the model may be used in everyday practice for perioperative counselling of patients and their carers.

Effect of adding dopexamine to intraoperative volume expansion in patients undergoing major elective abdominal surgery † †This article is accompanied by the Editorial

BACKGROUND

The contribution of low-dose dopexamine to outcome, when given to increase cardiac output in patients already treated with fluids during major abdominal surgery, is not yet known.

METHOD

We carried out a randomized double-blind placebo-controlled trial. All 100 patients studied were given fluid infusions during surgery guided by stroke volume measurements made with an oesophageal Doppler probe. Patients were randomized to receive dopexamine at the rate of 0.25 microg kg(-1) min(-1) or saline 0.9% (control) for the first 24 h after the start of surgery. The primary outcome measure was the incidence of postoperative morbidity.

RESULTS

There were no statistically significant differences between groups in the incidence of postoperative complications, the length of hospital stay, the incidence of morbidity and the use of critical care facilities. The patients randomized to receive dopexamine had significantly more pre-existing disease than the control patients. Mortality in both groups was significantly less than predicted by the POSSUM (Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity) risk prediction score.

CONCLUSION

We could not demonstrate an advantage to using low-dose dopexamine in high-risk patients during major abdominal surgery.

Towards a national clinical minimum data set for general surgery

Background

Measurement and comparison of surgical performance is accepted as necessary and inevitable. Risk-stratified (case-mix adjusted) models of clinical outcomes form a metric with which to assess performance, but require accurate data. Collecting such data in the clinical environment is time consuming and difficult. This study aimed to construct effective models, for operative and non-operative admissions, from routine clinical data residing in hospital computers, so minimizing data collection and quality problems, and facilitating national implementation.

Methods

Data for 3181 non-operative emergency, 5039 elective and 3043 emergency operative admissions for the 2 years beginning 1 August 1997 were used to generate logistic regression equations for risk of death, which were applied prospectively to the following 3 years' data.

Results

The models use urea, haemoglobin, white blood cell count, sodium, potassium, age on admission, sex, British United Provident Association (BUPA) Operative Severity Score (for operative admissions) and, implicitly, mode of admission and mortality at discharge. All three models successfully stratified risk into five or more bands.

Conclusion

Effective models of mortality, applicable to all general surgical admissions, can be constructed from existing routine clinical data, largely obtained from a single venesection. The data set is a candidate national clinical minimum data set.

A comparison of methods of adjusting stillbirth and neonatal mortality rates for birthweight in hospital and geographical populations

Birthweight-specific rates can be useful for summarising stillbirth and neonatal mortality in populations but, sometimes, a single summary measure is required to compare several relatively small subpopulations. However, any particular summary has its shortcomings, and various methods have been proposed. We wished to compare mortality between local authorities and between hospitals in the Thames regions and thus required a single summary measure for each subpopulation. It was not obvious in advance which summary to use or whether a single method would work well for both local authorities (a geographical unit) and hospitals. This study compared six methods of calculating a single summary, three using indirect standardisation to adjust (500 g bands, 10-percentile bands, 10 z-score bands) and three using regression to adjust (mean birthweight, proportion < 2500 g, proportion < 1500 g). The data used were 570 016 births in the Thames Regions, broken down into its 96 local authorities and 65 hospitals. To investigate how well each adjustment had performed, we calculated the rank correlation between the crude and various adjusted mortality rates and mean birthweight, proportion < 2500 g and proportion < 1500 g. This was done separately in the local authorities and hospitals. If a method of adjustment had worked very well, these correlations should be negligible. For the local authorities, adjustment for proportion < 1500 g gave the lowest correlations. Adjustment for mean birthweight and 500 g-band standardisation did not appear to work so well but gave moderately low correlations. For hospitals, 500 g standardisation gave the lowest correlations. Adjustment for mean birthweight and proportion < 2500 g worked only moderately well. Percentile and z-score adjustment did not work well for local authorities or hospitals. We conclude that several methods appear to work reasonably well for local authorities, whereas for hospitals, 500 g indirect standardisation worked best. Percentile and z-score standardisation did not work well in these subpopulations.

The Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM)

BACKGROUND AND METHODS

The development of the Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) is described and its methods of analysis and value in a modern surgical practice are reviewed. A computerized search of all published data in Medline, the Cochrane Library and Embase was made for the last 12 years. Relevant articles were then searched manually for further papers on risk analysis, case-mix comparison and POSSUM methodology.

RESULTS AND CONCLUSION

POSSUM has been evaluated extensively in both general and specialist surgery. While there are problems with both data collection and analysis, when used correctly POSSUM can usefully compare outcomes between surgeons and between hospitals. In specialist surgery, individual regression equations may be needed for each index procedure.

Risk-adjusted comparative audit. Is Possum applicable to head and neck surgery?

Possum (the physiological and operative severity score for the enumeration of mortality) is used in many surgical specialities for comparative audit. We investigated its validity in relation to head and neck surgery by retrospectively scoring 301 operative interventions. We also applied the P-Possum (Portsmouth Possum) equation for mortality. We compared our observed with the predicted outcomes. We introduced two new variables, radiotherapy and previous surgery to the operative site, to test their association with outcome. We found that Possum is valid for morbidity but predicts more accurately for high-risk than for low-risk groups. Neither Possum or P-Possum accurately predicts mortality. Radiotherapy and previous surgery were both significant for the development of postoperative complications (P = 0.002, P = 0.007 respectively) and are worthy of inclusion in a Possum score for head and neck surgery.

Comparison of POSSUM with P-POSSUM for prediction of mortality in infrarenal abdominal aortic aneurysm repair

The Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) is a simple and valid scoring system in predicting mortality and morbidity rates. The Portsmouth predictor equation (P-POSSUM) has been shown to be a more accurate predictor of death than the POSSUM in vascular patients. The length of hospital stay (LOS) equation has been suggested to be of value in predicting total length of stay. The aim of this study was to test the validity of the POSSUM, P-POSSUM, and LOS in predicting outcome of patients undergoing abdominal aortic aneurysm (AAA) repair. POSSUM scores in 118 patients who underwent AAA repair by a single consultant were recorded retrospectively. Observed rates of mortality, morbidity, and length of hospital stay were correlated with the rates predicted by POSSUM, P-POSSUM, and LOS equations in three groups: all cases, 93 elective repairs, and emergency AAA repairs. The POSSUM and the P-POSSUM performed similarly in terms of accuracy of prediction, with all predicted values being not significantly different from those observed. The POSSUM tended to overpredict mortality compared to the P-POSSUM. The POSSUM predicted morbidity well. The LOS equation failed to predict significantly observed total hospital stay. POSSUM and P-POSSUM outcome risk equations are thus valid in predicting mortality for all cases and emergency AAA repairs. The POSSUM morbidity equation predicts complications quantitatively.

Adjusted mortality rates: a tool for creating more meaningful league tables for stillbirth and infant mortality rates

A number of problems associated with league tables of performance indicators have been discussed in the literature. This paper attempts to address these problems for stillbirth and infant mortality rates in order to produce meaningful and useful information for the government, general public and health professionals. Composite stillbirth and infant mortality rates, low birth-weight and very low birth-weight rates were determined for the 100 English Health Authorities for 1996-1997. Townsend deprivation scores for these districts were also obtained. The mortality rates were adjusted by multiple regression for very low birth-weight and Townsend score separately and together. Confidence intervals were calculated for the dual-adjusted rates. Almost 60% of the variability in mortality rates were explained by Townsend score and very low birth-weight rates together. Adjusted league tables showed how the individual and combined predictors affect the individual mortality rates for each Health Authority. There was considerable overlap in the confidence intervals for the adjusted rates although there were a few Health Authorities whose mortality rates were clearly below most others. We conclude that fairer and more useful information is provided by geographically based league tables which give both crude rates and rates adjusted for single and multiple predictor variables. The inclusion of confidence intervals aids interpretation of annual random variations and knowledge of differences in the effects of the individual predictors enables better resource targeting.

Evaluation of the P-POSSUM mortality prediction algorithm in Australian surgical intensive care unit patients

BACKGROUND

The Physiological and Operative Severity Score for enUmeration of Mortality and Morbidity (POSSUM) is an auditing tool designed to compare surgical outcomes independent of case mix. It uses patient physiological and operative data to predict morbidity and mortality for surgical patients. Thus far most evaluations of the POSSUM algorithm and its modifications have emanated from British hospitals. A single-centre retrospective study was therefore performed to determine the applicability of this tool to the Australian surgical case mix.

METHODS

All surgical patients undergoing a surgical procedure admitted to the Royal Brisbane Hospital intensive care facility in 1999 were reviewed retrospectively. Mortality predictions using the Portsmouth modification of the POSSUM algorithm (P--POSSUM) were compared to the actual outcomes using receiver-operator characteristic curve analysis and the Hosmer and Lemeshow Goodness-of-Fit test.

RESULTS

The records of 229 admissions were reviewed. The area under the receiver-operator characteristic curve was 0.68, significantly greater than 0.5 (P = 0.014). Predicted deaths were significantly greater than actual deaths (50 vs 28, P < 0.001), with over-prediction of death rates in all mortality groupings except the two lowest risk deciles.

CONCLUSION

The P-POSSUM algorithm tends to over-estimate mortality in surgical intensive care patients. It may require further calibration before adoption as a surgical audit tool in Australia.

Evaluation of POSSUM in patients with oesophageal cancer undergoing resection

BACKGROUND

The Physiogical and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) has been used to produce a numerical estimate of expected mortality and morbidity after a variety of general surgical procedures. The aim of this study was to evaluate the ability of POSSUM to predict mortality and morbidity in patients undergoing oesophagectomy.

METHODS

POSSUM predictor equations for morbidity and mortality were applied retrospectively to 204 patients who had undergone oesophagectomy for cancer. Observed morbidity and mortality rates were compared with rates predicted by POSSUM using the Hosmer-Lemeshow goodness-of-fit test. Evaluation of the discriminative capability of POSSUM predictor equations was performed using receiver-operator characteristic (ROC) curve analysis.

RESULTS

The observed and predicted mortality rates were 12.7 and 19.1 per cent respectively, and the respective morbidity rates were 53.4 and 62.3 per cent. However, the POSSUM model showed a poor fit with the data both for the observed 30-day mortality (chi2 = 16.26, P = 0.002) and morbidity (chi2 = 63.14, P < 0.001) using the Hosmer-Lemeshow test. ROC curve analysis revealed that POSSUM had poor predictive accuracy both for mortality (area under curve 0.62) and morbidity (area under curve 0.55).

CONCLUSION

These data suggest that POSSUM does not accurately predict mortality and morbidity in patients undergoing oesophagectomy and must be modified.