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Background: Anastomotic leak is a dreaded complication of intestinal surgery and has been associated with a high mortality rate. But it is uncertain exactly which patient populations are at risk of death from the leak. We sought to assess the impact of surgeon volume on leak rate and to better understand the relationship of a leak to postoperative mortality., Study Design: All adult patients having a small or large bowel resection with anastomosis at a university hospital from July 2003 to June 2006 were entered into a prospectively maintained quality database; data were entered by a specially trained nurse practitioner who rounded daily with housestaff. Patients with a postoperative leak based on standardized criteria were identified. Patient characteristics, surgical procedure, and operating surgeon were noted. Overall complication and leak rates by surgeon were compared using Fisher's exact test. Individual case review by a group of peers was performed for all patients with a leak who died, to determine the relationship to mortality., Results: Five hundred fifty-six patients underwent resection with anastomosis during the study period. There were 27 patients with leaks (4.9%), 6 of whom died. Leak rate for the highest-volume surgeons ranged from 1.6% to 9.9% (p <0.01), and overall complication rate varied from 30.5% to 44% (p=0.04). In four of six deaths, leaks occurred in very ill patients undergoing emergency procedures and appeared to be premorbid events. In only one patient did the leak appear to be the primary cause of death., Conclusions: The variability in leak rate by surgeons doing similar operations suggests that many leaks may be preventable. But death after a leak is most often a surrogate for a critically ill patient and was infrequently the actual cause of death.

Objective: To determine whether imputed data can be used to produce unbiased hospital quality measures., Background: Different methods for handling missing data may influence which hospitals are designated as quality outliers., Methods: Monte-Carlo simulation study based on 63,020 patients with no missing data in 68 hospitals using the National Trauma Data Bank (NTDB, version 6.1). Patients were assigned missing data for the motor component of the Glasgow coma scale (GCS) conditional on their observed clinical risk factors. Multiple imputation was then used to "fill in" the missing data. Hospital risk-adjusted quality measures (observed-to-expected mortality ratio) based either on (1) imputed data, (2) excluding patients with missing data (complete case analysis), or (3) excluding the predictor with missing data were compared with hospital quality based on the true data (no missing data). Pair-wise comparisons of hospital quality were performed using the intraclass correlation coefficient (ICC) and the kappa statistic., Results: With 10% of the data missing, the level of agreement between multiple imputation and the true data (ICC = 0.99 and kappa = 0.87) was better compared with the level of agreement between complete case analysis and the true data (ICC = 0.93 and kappa = 0.62). Excluding the predictor (motor GCS) with missing data from the risk adjustment model resulted in the least amount of agreement with quality assessment based on the true data (ICC = 0.88 and kappa = 0.46)., Conclusion: Multiple imputation can be used to impute missing data and yields hospital quality measures that are nearly identical to those based on the true data. Simply excluding patients with missing data or excluding risk factors with missing data from hospital quality assessment yields substantially inferior quality measures.

Background: The Agency for Healthcare Research and Quality (AHRQ) Patient Safety Indicators (PSIs) provide information on hospital risk-adjusted rates for potentially preventable adverse events. Although designed to work with routine administrative data, it is unknown whether the PSIs can accurately distinguish between complications and pre-existing conditions. The objective of this study is to examine whether the AHRQ PSIs accurately measure hospital complication rates, using the data with present-on-admission (POA) codes to distinguish between complications and pre-existing conditions, Methods: Retrospective cohort study of patients undergoing isolated CABG surgery in California conducted using the 1998-2000 California State Inpatient Database. We calculated the positive predictive value of selected AHRQ PSIs using information from the POA as the gold standard, and the intra-class correlation coefficient to assess the level of agreement between the hospital risk-adjusted PSI rates with and without the information contained in the POA modifier., Results: The false positive error rate, defined as one minus the positive predictive value, was greater than or equal to 20% for four of the eight PSIs examined: decubitus ulcer, failure-to-rescue, postoperative physiologic and metabolic derangement, and postoperative pulmonary embolism or deep venous thrombosis. Pairwise comparison of the hospital risk-adjusted PSI rates, with and without POA information, demonstrated almost perfect agreement for five of the eight PSI's. For decubitus ulcer, failure-to-rescue, and postoperative pulmonary embolism or DVT, the intraclass-correlation coefficient ranged between 0.63 to 0.79., Conclusion: For some of the AHRQ Patient Safety Indicators, there are significant differences in the risk-adjusted rates of adverse events depending on whether the POA indicator is used to distinguish between pre-existing conditions and complications. The use of the POA indicator will increase the accuracy of the AHRQ PSIs as measures of adverse outcomes.

Purpose: Transanal endoscopic microsurgery, developed by Buess in the 1980s, has become increasingly popular in recent years. No large studies have compared the effectiveness of transanal endoscopic microsurgery with traditional transanal excision., Methods: Between 1990 and 2005, 171 patients underwent traditional transanal excision (n = 89) or transanal endoscopic microsurgery (n = 82) for rectal neoplasms. Medical records were reviewed to determine type of surgery, resection margins, specimen fragmentation, complications, recurrence, lesion type, stage, and size., Results: The groups were similar with respect to age, sex, lesion type, stage, and size. Mean follow-up was 37 months. There was no difference in the complication rate between the groups (transanal endoscopic microsurgery 15 percent vs. traditional transanal excision 17 percent, P = 0.69). Transanal endoscopic microsurgery was more likely to yield clear margins (90 vs. 71 percent, P = 0.001) and a nonfragmented specimen (94 vs. 65 percent, P < 0.001) compared with transanal excision. Recurrence was less frequent after transanal endoscopic microsurgery than after traditional transanal excision (5 vs. 27 percent, P = 0.004)., Conclusions: Transanal endoscopic microsurgery is the technique of choice for local excision of rectal neoplasms.

Objective: To develop a statistically rigorous trauma mortality prediction model based on empiric estimates of severity for each injury in the abbreviated injury scale (AIS) and compare the performance of this new model with the injury severity score (ISS)., Summary Background Data: Mortality rates at trauma centers should only be compared after adjusting for differences in injury severity, but no reliable measure of injury severity currently exists. The ISS has served as the standard measure of anatomic injury for 30 years. However, it relies on the individual injury severities assigned by experts in the AIS, is nonmonotonic with respect to mortality, and fails to perform even as well as a far simpler model based on the single worst injury a patient has sustained., Methods: This study is based on data from 702,229 injured patients in the National Trauma Data Bank (NTDB 6.1) hospitalized between 2001 and 2005. Sixty percent of the data was used to derive an empiric measure of severity of each of the 1322 injuries in the AIS lexicon by taking the weighted average of coefficients estimated using 2 separate regression models. The remaining 40% of the data was use to create 3 exploratory mortality prediction models and compare their performance with the ISS using measures of discrimination (C statistic), calibration (Hosmer Lemeshow statistic and calibration curves), and the Akaike information criterion., Results: Three new models based on empiric AIS injury severities were developed. All of these new models discriminated survivors from nonsurvivors better than the ISS, but one, the trauma mortality prediction model (TMPM), had both better discrimination [ROCTMPM = 0.901 (0.898-0.905), ROCISS = 0.871 (0.866-0.877)] and better calibration [HLTMPM = 58 (35-91), HLISS = 296 (228-357)] than the ISS. The addition of age, gender, and mechanism of injury improved all models, but the augmented TMPM dominated ISS by every measure [ROCTMPM = 0.925(0.921-0.928), ROCISS = 0.904(0.901-0.909), HLTMPM = 18 (12-31), HLISS = 54 (30-64)]., Conclusions: Trauma mortality models based on empirical estimates of individual injury severity better discriminate between survivors and nonsurvivors than does the current standard, ISS. One such model, the TMPM, has both superior discrimination and calibration when compared with the ISS. The TMPM should replace the ISS as the standard measure of overall injury severity.

Context: It is unknown whether high-risk cardiac surgical patients have less access to high-quality surgeons compared with lower-risk patients., Objective: To determine whether high-quality surgeons are less likely to perform coronary artery bypass graft (CABG) surgery on high-risk patients compared with low-quality surgeons., Design, Setting, and Patients: Retrospective cohort study using the New York State (NYS) CABG Surgery Reporting System (CSRS) of all patients undergoing CABG surgery in NYS who were discharged between 1997 and 1999 (51,750 patients; 2.20 percent mortality). Regression modeling was used to estimate the association between surgeon quality and patient risk of death. Surgeon quality was quantified using the observed-to-expected mortality ratio (O-to-E ratio)., Results: Higher-risk patients are more likely to receive CABG surgery from higher-quality surgeons. For every 10 percentage point increase in patient risk of death (e.g., from 5 to 15 percent), there is an absolute reduction of 0.034 in the surgeon O-to-E ratio (p < .001)., Conclusion: This study suggests that high-risk CABG patients are significantly more likely to receive care from high-quality surgeons compared with lower risk patients.

Background: The Agency for Healthcare Research and Quality (AHRQ) has constructed Inpatient Quality Indicator (IQI) mortality measures to measure hospital quality using routinely available administrative data. With the exception of California, New York State, and Wisconsin, administrative data do not include a present-on-admission (POA) indicator to distinguish between preexisting conditions and complications. The extent to which the lack of a POA indicator biases quality assessment based on the AHRQ mortality measures is unknown., Objective: To examine the impact of the POA indicator on hospital quality assessment based on the AHRQ mortality measures using enhanced administrative data from California, which includes a POA indicator., Methods: Retrospective cohort study based on 2.07 million inpatient admissions between 1998 and 2000 in the California State Inpatient Database. The AHRQ IQI software was used to calculate risk-adjusted mortality rates using either (1) routine administrative data that included all the International Classification of Diseases (ICD)-9-CM codes or (2) enhanced administrative data that included only the ICD-9-CM codes representing preexisting conditions., Results: The inclusion of the POA indicator frequently results in changes in the quality ranking of hospitals classified as high-quality or low-quality using routine administrative data. Twenty-seven percent (stroke) to 94% (coronary artery bypass graft) of hospitals classified as high-quality using routine administrative data were reclassified as intermediate- or low-quality hospitals using the enhanced administrative data. Twenty-five percent (congestive heart failure) to 76% (percutaneous coronary intervention) of hospitals classified as low-quality hospitals using enhanced administrative data were misclassified as intermediate-quality hospitals using routine administrative data., Conclusions: Despite the fact that the AHRQ IQIs were primarily intended to serve as a screening tool, they are being increasingly used to publicly report hospital quality. Our findings emphasize the need to improve the "quality" of administrative data by including a POA indicator if these data are to serve as the information infrastructure for quality reporting.

Background: Endoscopic sclerotherapy with sodium morrhuate of a dilated gastrojejunostomy in gastric bypass patients has been shown to narrow the diameter of the anastomosis and provide weight loss or weight stability 3-6 months after the procedure. Longer term results for this procedure are needed., Methods: From 1999 to 2006, sclerotherapy was performed on 147 gastric bypass patients with a dilated gastrojejunostomy. In a retrospective review, 32 patients were identified for whom > or =12 months of postprocedure data were available. Their weight trends before and after treatment were assessed by paired t test., Results: A total of 32 patients who were gaining weight after gastric bypass underwent sclerotherapy of their dilated gastrojejunostomy. The timing of treatment ranged from 10 to 140 months (average 56) after Roux-en-Y gastric bypass. Before sclerotherapy, patients were gaining weight at a rate of .36 kg/mo. After treatment, they were losing weight at a rate of .39 kg/mo. After treatment, 56.3% of patients began to lose weight, 34.4% had their weight stabilize, and 9.4% continued to gain weight., Conclusion: The results of our study have shown that sclerotherapy for a dilated gastrojejunostomy after gastric bypass is a minimally invasive procedure that provides a 91.6% chance of postprocedure weight loss or stabilization for 1 year after treatment.

Background: Administrative databases oversimplify the relationship of factors such as volume or training on surgical outcomes., Methods: A prospective statewide surgeon-initiated database was queried to obtain incident cases of rectal cancer in Vermont from April 1999 to June 2001. Demographics, procedure performed, method of detection, American Society of Anesthesiologists classification, blood transfusions, length of stay, complications, stage, and use of adjuvant therapy were recorded by the operating surgeon. A post hoc analysis was performed on patients operated on for rectal cancer to define the specific impact of specialty training on care patterns., Results: There was a marked difference in the distribution of surgical procedures, with colorectal surgeons using local excision and coloanal anastomosis in addition to anterior and abdominoperineal resection. Although the overall use of adjuvant therapy was similar, patients in the colorectal group were more likely to receive preoperative then postoperative radiation therapy (91% vs 17%, P <.0001) and more likely to receive radiation therapy when stage appropriate (98% vs 67%, P <.001)., Conclusions: Colorectal specialty training in this population was a surrogate for a wider array of surgical options and preoperative radiation. Failure to use radiation when stage-appropriate was related to patient comorbidities and/or refusal and not related to failure of the surgeon to offer adjuvant therapy. Prospective, surgeon-initiated databases provide an excellent opportunity to identify and understand practice variability.

Background: Vena cava filters (VCFs) have been advocated for prophylaxis of pulmonary embolism in trauma patients at high risk for venous thrombosis in whom anticoagulation is contraindicated or not feasible. We sought to determine the frequency of VCF insertion and patterns of use in trauma patients using a large database., Methods: Retrospective analysis of data from the National Trauma Data Bank of the American College of Surgeons on patients over the age of 17 years from 1991 to 2002. We examined the annual frequency of VCF placement, the demographics and injury severity of patients receiving them, and the characteristics of the hospitals at which they were being placed., Results: Of 614,349 patients, 6,282 received a VCF (1%); 86% were placed prophylactically (without an associated discharge diagnosis of either pulmonary embolism or venous thrombosis). Filter use increased significantly from 0.3% of patients in 1994 to 1.2% in 2002 (p < 0.001). There was substantial variation in clinical practice with regard to placement of VCF according to injury type and its perceived risk of venous thromboembolism. VCFs were placed significantly more frequently at hospitals verified as Level I trauma centers., Conclusion: VCF insertion has increased significantly during the past 10 years in trauma patients reported to the National Trauma Data Bank. The lack of an evidence-based guideline for their use has resulted in a wide variation in practice. Such variation in practice indicates the need for a consensus conference or a multicenter prospective clinical trial to determine their role in trauma patients.

Background: Case volume and training have been considered as reasonable surrogates for competency that can be used as a basis to grant privileges for performing laparoscopic operations. To determine the validity of this practice, we assessed the relationship of surgical volume and training to provider-related complications after laparoscopic bowel resection., Study Design: All patients undergoing open or laparoscopic resection at a university hospital from July 2003 to June 2006 were entered into a prospectively maintained database. Complications were recorded by a specially trained nurse practitioner and adjudicated monthly by a team of gastrointestinal surgeons. Surgeon case volume, training, and operative indication were assessed for their ability to predict technical complications after laparoscopic resection using a logistic regression model., Results: Six hundred twenty-four bowel resections were performed during the study period, of which 112 were performed laparoscopically. Of the four study surgeons, the percentage of laparoscopic versus open cases ranged from 8% to 56%. Individual surgeon complication rates varied from 9% to 47%. Surgical volume and training had no notable relationship to incidence of complications (19% high volume/fellowship training versus 10% low volume/no fellowship, p = 0.25). An inflammatory indication was a strong predictor of technical complications on univariate (p = 0.02) and multivariate (p = 0.01) analysis., Conclusions: Surgeon case volume and training had no relationship to the complication rate after laparoscopic bowel operation. Case selection is a critical confounding variable because surgeons vary so greatly in their indications for using laparoscopic technique. Although documentation of training is appropriately considered in granting privileges, actually tracking outcomes is likely the only reliable way to assess competency.

Objective: To examine whether basing regionalization on risk-adjusted mortality would lead to better population outcomes than basing regionalization on procedure volume., Data Source: We used secondary data from the California State Inpatient Database obtained from the Healthcare Costs and Utilization Project., Study Design: A population-based retrospective cohort study of 243 thousand patients who underwent either abdominal aortic aneurysm surgery, coronary artery bypass surgery or coronary angioplasty between 1998 and 2000 in California. Four regionalization strategies were compared: (i) selective referral to high-quality hospitals; (ii) selective referral to high-volume hospitals; (iii) selective avoidance of low-quality hospitals; (iv) selective avoidance of low-volume hospitals., Principal Findings: Selective referral to high volume centers would be only moderately effective (2-20% relative reduction in mortality) and extremely disruptive (70-99% reduction in the number of hospitals treating these conditions). Selective referral to high quality centers was estimated to result in dramatic reduction in mortality (50%) but would also be highly disruptive with greater than 80% of the patients re-directed to high quality centers. Selective avoidance of low volume hospitals would not improve mortality, whereas selective avoidance of low quality hospitals was estimated to result in a small improvement in overall mortality (2-6%) while causing relatively minor disruptions in patient referral patterns., Conclusion: Efforts to use volume standards as the basis for evidence-based hospital referrals should be re-evaluated by all stake-holders before promoting further efforts to regionalize health care delivery using volume cutoffs.

Objective: Complications are associated with increased risk of death. The objective of this study is to quantify the increased odds of dying from complications after isolated coronary artery bypass grafting surgery., Methods: We conducted a retrospective cohort study using the New York State Coronary Artery Bypass Grafting Surgery Reporting System for all patients undergoing isolated coronary artery bypass grafting surgery in New York State who were discharged between 1997 and 1999 (51,750 patients; 2.20% mortality). We estimated the independent effect of individual postoperative complications on in-hospital mortality after controlling for patient clinical risk factors and demographics., Results: The mortality rate for patients without complication was 0.77% versus 16.1% for patients with complications (P < .001). After adjusting for preoperative risk factors, transmural myocardial infarction (adjusted odds ratio, 7.90; P < .001), respiratory failure (adjusted odds ratio, 6.02; P < .001), renal failure (adjusted odds ratio, 7.15; P < .001), and stroke within 24 hours (adjusted odds ratio, 4.09; P < .001) were the most strongly associated with mortality., Conclusions: There is a strong association between postoperative complications and in-hospital mortality. Complications after isolated coronary artery bypass grafting surgery are associated with a 1.4- to 8-fold increase in the odds of death after adjusting for severity of disease and comorbidities. This information might prove valuable to hospitals in their efforts to design quality improvement initiatives and care protocols to improve mortality after coronary artery bypass grafting surgery.

Background: Although public reporting of hospital and physician performance is a cornerstone of the effort to improve health care quality, the optimal approach to risk adjustment is unknown., Objective: We sought to assess hospital quality using a matching algorithm based on a generalized distance metric and to compare this approach to the more traditional regression-based approach. DESIGN/ DATA SOURCE: This was a retrospective study using the New York State (NYS) Coronary Artery Bypass Surgery Reporting System (CSRS), focusing on all patients undergoing isolated CABG surgery in NYS who were discharged in 1999 (18,116 patients). Patients from specific hospital were matched to a control group using the Mahalanobis distance. The hospitals' expected mortality rate was calculated in 2 ways: (1) as the mortality rate of the control group or (2) as the mortality rate predicted by the NYS CABG model. Hospitals whose observed mortality rate was significantly different from their expected mortality rate (OE difference) were defined as quality outliers., Results: The 2 risk-adjustment methodologies disagreed on the outlier status of 4 of the 33 hospitals. Kappa analysis demonstrated substantial agreement between these 2 methods for identifying quality outliers: kappa = 0.61. There was excellent agreement between the point estimates of the OE difference obtained using these 2 risk adjustment methodologies., Conclusion: Basing outcome assessment on either matching or regression modeling yielded similar findings on hospital ranking but only moderate level of agreement on hospital quality. The use of matching may enhance the transparency and acceptance of outcome report cards by hospitals and physicians.

Purpose: Anastomotic leaks are among the most dreaded complications after colorectal surgery. However, problems with definitions and the retrospective nature of previous analyses have been major limitations. We sought to use a prospective database to define the true incidence and presentation of anastomotic leakage after intestinal anastomosis., Methods: A prospective database of two colorectal surgeons was reviewed over a 10-year period (1995-2004). The incidence of leak by surgical site, timing of diagnosis, method of detection, and treatment was noted. Complications were entered prospectively by a nurse practitioner directly involved in patient care. Standardized criteria for diagnosis were used. A logistic regression model was used to discriminate statistical variation., Results: A total of 1223 patients underwent resection and anastomosis during the study period. Mean age was 59.1 years. Leaks occurred in 33 patients (2.7%). Diagnosis was made a mean of 12.7 days postoperatively, including four beyond 30 days (12.1%). There was no difference in leak rate by surgeon (3.6% vs. 2.2%; P = 0.08). The leak rate was similar by surgical site except for a markedly increased leak rate with ileorectal anastomosis (P = 0.001). Twelve leaks were diagnosed clinically versus 21 radiographically. Contrast enema correctly identified only 4 of 10 leaks, whereas CT correctly identified 17 of 19. A total of 14 of 33 (42%) patients had their leak diagnosed only after readmission. Fifteen patients required fecal diversion, whereas 18 could be managed nonoperatively., Conclusions: Anastomotic leaks are frequently diagnosed late in the postoperative period and often after initial hospital discharge, highlighting the importance of prospective data entry and adequate follow-up. CT scan is the preferred diagnostic modality when imaging is required. More than half of leaks can be managed without fecal diversion.

Background: There is strong evidence that pain is undertreated in black and Hispanic patients. The association between race and ethnicity and the use of epidural analgesia for labor is not well described., Methods: Using the New York State Perinatal Database, the authors examined whether race and ethnicity were associated with the likelihood of receiving epidural analgesia for labor after adjusting for clinical characteristics, demographics, insurance coverage, and provider effect. This retrospective cohort study was based on 81,883 women admitted for childbirth between 1998 and 2003., Results: Overall, 38.3% of the patients received epidural analgesia for labor. After adjusting for clinical risk factors, socioeconomic status, and provider fixed effects, Hispanic and black patients were less likely than non-Hispanic white patients to receive epidural analgesia: The adjusted odds ratio was 0.85 (95% CI, 0.78-0.93) for white/Hispanic and 0.78 (0.74-0.83) for blacks compared with non-Hispanic whites. Compared with patients with private insurance, patients without insurance were least likely to receive epidural analgesia (adjusted odds ratio, 0.76; 95% CI, 0.64-0.89). Black patients with private insurance had similar rates of epidural use to white/non-Hispanic patients without insurance coverage: The adjusted odds ratio was 0.66 (95% CI, 0.53-0.82) for white/non-Hispanic patients without insurance versus 0.69 (0.57-0.85) for black patients with private insurance., Conclusion: Black and Hispanic women in labor are less likely than non-Hispanic white women to receive epidural analgesia. These differences remain after accounting for differences in insurance coverage, provider practice, and clinical characteristics.

Context: Many of the publicly available health quality report cards are based on administrative data. ICD-9-CM codes in administrative data are not date stamped to distinguish between medical conditions present at the time of hospital admission and complications, which occur after hospital admission. Treating complications as preexisting conditions gives poor-performing hospitals "credit" for their complications and may cause some hospitals that are delivering low-quality care to be misclassified as average- or high-performing hospitals., Objective: To determine whether hospital quality assessment based on administrative data is impacted by the inclusion of condition present at admission (CPAA) modifiers in administrative data as a date stamp indicator., Design, Setting, and Patients: Retrospective cohort study based on 648,866 inpatient admissions between 1998 and 2000 for coronary artery bypass graft (CABG) surgery, coronary angioplasty (PTCA), carotid endarterectomy (CEA), abdominal aortic aneurysm (AAA) repair, total hip replacement (THR), acute MI (AMI), and stroke using the California State Inpatient Database which includes CPAA modifiers. Hierarchical logistic regression was used to create separate condition-specific risk adjustment models. For each study population, one model was constructed using only secondary diagnoses present at admission based on the CPAA modifier: "date stamp" model. The second model was constructed using all secondary diagnoses, ignoring the information present in the CPAA modifier: the "no date stamp model." Hospital quality was assessed separately using the "date stamp" and the "no date stamp" risk-adjustment models., Results: Forty percent of the CABG hospitals, 33 percent of the PTCA hospitals, 40 percent of the THR hospitals, and 33 percent of the AMI hospitals identified as low-performance hospitals by the "date stamp" models were not classified as low-performance hospitals by the "no date stamp" models. Fifty percent of the CABG hospitals, 33 percent of the PTCA hospitals, 50 percent of the CEA hospitals, and 36 percent of the AMI hospitals identified as low-performance hospitals by the "no date stamp" models were not identified as low-performance hospitals by the "date stamp" models. The inclusion of the CPAA modifier had a minor impact on hospital quality assessment for AAA repair, stroke, and CEA., Conclusion: This study supports the hypothesis that the use of routine administrative data without date stamp information to construct hospital quality report cards may result in the mis-identification of hospital quality outliers. However, the CPAA modifier will need to be further validated before date stamped administrative data can be used as the basis for health quality report cards.

Objective: Expert task forces have proposed that adult critical care medicine services should be regionalized in order to improve outcomes. However, it is currently unknown if high intensive care unit (ICU) patient volumes are associated with reduced mortality rate. The objective was to investigate whether high-volume ICUs have better mortality outcomes than low-volume ICUs., Design: Retrospective cohort study analyzing the association between ICU volume and in-hospital mortality using Project IMPACT (a clinical outcomes database created by the Society of Critical Care Medicine)., Patients: The analyses were based on 70,757 patients admitted to 92 ICUs between 2001 and 2003., Interventions: None., Measurements and Main Results: The main outcome measure was in-hospital mortality. Hierarchical logistic regression modeling was used to examine the volume-outcome association. The median (interquartile range) ICU volume was 827 (631-1,234) patient admissions per year. The overall mortality rate was 14.6%. After controlling for patient risk factors and ICU characteristics, and clustering, there was evidence that patients admitted to high-volume ICUs had improved outcomes (p = .025). However, this mortality benefit was seen only in high-risk patients treated at ICUs treating high volumes of high-risk patients., Conclusions: There is evidence that high ICU patient volumes are associated with lower mortality rates in high-risk critically ill adults.

Background: The Trauma and Injury Severity Score (TRISS), used to garner predictions of survival from the Injury Severity Score (ISS), the Revised Trauma Score (RTS, for physiologic reserve), and age is difficult for many trauma facilities to compute because it requires 8 to 10 variables and ISS depends on the specialized Abbreviated Injury Scale (AIS) scale rather than the International Classification of Diseases scale (ICD-9). It has been shown that metrics describing a patient's worst injury (WORSTSRR) are a powerful predictor of survival (regardless of coding type, AIS versus ICD-9) and that the Glasgow Coma Scale (GCS) motor component contains the majority of the information found in the full GCS score. This study hypothesized that the TRISS approach could be made more predictive and efficient with fewer variables by incorporating these advances., Methods: A total of 310,958 patients with nonmissing TRISS variables were subset from the National Trauma Data Bank (NTDB). Logistic regression was used to model mortality as a function of anatomic, physiologic and age variables. A traditional TRISS model was computed (with NTDB-derived coefficients) that uses ISS, RTS, age index, and mechanism to predict survival. Four smaller three- or four-variable models employed the ICD-9 WORSTSRR, the GCS motor component, and age (both continuously and dichotomously). Two of the four models also use mechanism. These models were compared using the concordance index (c-index, a measure of model discrimination) and the pseudo-R statistic (estimates proportion of variance explained)., Results: Each experimental model (two models with 3 variables and two models with 4 variables) have superior discrimination and explain more variance than the traditional TRISS model that employs 8-10 variables., Conclusions: Recent advances in anatomic and physiologic scoring markedly simplify TRISS-type models at no cost to prediction. This approach uses routinely available data, requires up to seven fewer terms, and predicts at least as well as the original TRISS. These findings could increase the availability of accurate trauma scoring tools to smaller trauma facilities.

Background: Risk adjustment is central to the generation of health outcome report cards. It is unclear, however, whether risk adjustment should be based on standard logistic regression, fixed-effects or random-effects modeling., Objective: The objective of this study was to determine how robust the New York State (NYS) Coronary Artery Bypass Graft (CABG) Surgery Report Card is to changes in the underlying statistical methodology., Methods: Retrospective cohort study based on data from the NYS Cardiac Surgery Reporting System on all patient undergoing isolated CABG surgery in NYS and who were discharged between 1997 and 1999 (51,750 patients). Using the same risk factors as in the NYS models, fixed-effects and random-effects models were fitted to the NYS data. Quality outliers were identified using 1) the ratio of observed-to-expected mortality rates (O/E ratio) and confidence intervals (CIs) calculated using both parametric (Poisson distribution) and nonparametric (bootstrapping) techniques; and 2) shrinkage estimators., Results: At the surgeon level, the standard logistic regression model, the fixed-effects model, and the fixed-effects component of the random-effects model demonstrated near-perfect agreement on the identity of quality outliers using a quality indicator based on the O/E ratio and the Poisson distribution. Shrinkage estimators identified the fewest outliers, whereas the O/E ratios with bootstrap CI identified the greatest number of outliers. The results were similar for hospitals, except that the fixed-effects model identified more outliers than either the NYS model or the fixed-effects component of the random-effects model., Conclusion: Shrinkage estimators based on random-effects models are slightly more conservative in identifying quality outliers compared with the traditional approach based on fixed-effects modeling and standard regression. Explicitly modeling surgeon provider effect (fixed-effects and random-effects models) did not significantly alter the distribution of quality outliers when compared with standard logistic regression (which does not model provider effect). Compared with the standard parametric approach, the use of a bootstrap approach to construct 95% confidence interval around the O/E ratio resulted in more providers being identified as quality outliers.

Context: Comorbidity measures are designed to exclude complications when they map International Classification of Diseases (ICD-9-CM) codes to diagnostic categories. The use of data fields that indicates whether each secondary diagnosis was present at the time of hospital admission may lead to the more accurate identification of preexisting conditions., Objective: To examine the rate of misclassification of ICD-9-CM codes into diagnostic categories by the Dartmouth-Manitoba adaptation of the Charlson index and by the Elixhauser comorbidity algorithm., Data Source: Analysis of 178,838 patients in the California State Inpatient Database (CA SID) admitted in 2000 for one of seven major medical and surgical conditions. The CA SID includes a condition present at admission (CPAA) modifier for each ICD-9-CM code., Study Design: The Dartmouth/Charlson index and the Elixhauser comorbidity measure were used to map the ICD-9-CM codes into diagnostic categories for patients in each study population. We calculated the misclassification rate for each mapping algorithm, using information from the CPAA as the "gold standard.", Principal Findings: The Dartmouth/Charlson index underestimated the prevalence of hemiplegia/paraplegia by 70 percent, cerebrovascular disease by 70 percent, myocardial infarction by 65 percent, congestive heart failure (CHF) by 45 percent, and peptic ulcer disease by 34 percent. The Elixhauser algorithm misclassified complications as preexisting conditions for 43 percent of the coagulopathies, 25 percent of the fluid and electrolyte disorders, 18 percent of the cardiac arrhythmias, 18 percent of the cardiac arrhythmias, and 9 percent of the cases of CHF., Conclusion: Adding the CPAA modifier to administrative data would significantly enhance the ability of the Dartmouth/Charlson index and of the Elixhauser algorithm to map ICD-9-CM codes to diagnostic categories accurately.

Background: Placement of vena cava filters (VCFs) in high-risk adult trauma patients is a well-described intervention for prophylaxis against pulmonary embolism (PE). Few data exist regarding the use of VCFs in pediatric trauma., Methods: We performed a cross-sectional study using the National Trauma Data Bank of the American College of Surgeons. Patients 17 years old or younger were included. Data regarding demographics, injuries, hospitalization, survival, and treating institution were analyzed. The prevalence of deep vein thrombosis (DVT), PE, and VCF placement were calculated. Odds ratios (ORs) for predictors of VCF placement were determined using multivariate logistic regression., Results: There were 116,357 pediatric patients in the National Trauma Data Bank. VCFs were placed in 214 (0.18%) patients. VCF patients had longer mean hospital (23.99 vs. 4.12 days) and intensive care unit stays (13.65 vs. 1.12 days) and more severe injuries (mean Injury Severity Score, 30.89 vs. 9.04) than those without VCFs. Sixty-five patients had DVT, and PE was diagnosed in 28 patients, representing 0.06% and 0.02% of the cohort, respectively. University-associated teaching hospitals placed 72.4% (95% confidence interval, 65.9-78.3%) of VCFs and Level I trauma centers placed 46.3% (95% confidence interval, 39.4-53.2%) of VCFs. In multivariate analysis, significant predictors of VCF use were DVT (OR, 33.13), spinal cord injury (OR, 15.28), probability of survival (OR, 10.52), severe femur fracture (OR, 3.39), increasing age (OR, 1.99), ISS (OR, 1.05), intensive care unit stay (OR, 1.04), and length of stay (OR, 1.02). Higher Glasgow Coma Scale score decreased the likelihood of VCF use (OR, 0.87)., Conclusion: Placement of VCFs in pediatric trauma patients is uncommon and is associated with several characteristics of the patient, the injury, and the treating institution. Long-term VCF efficacy in pediatric trauma is not known, and application of VCFs in these patients requires further investigation.

Hypothesis: Colonoscopic localization of colorectal carcinoma is frequently inaccurate and unreliable., Design: Consecutive case series., Setting: Tertiary care teaching hospital., Patients: Three hundred fourteen consecutive patients undergoing surgical resection for colorectal cancer from January 1, 2000, to December 31, 2003., Intervention: Surgical resection for colorectal cancer., Main Outcome Measure: Incidence of erroneous site localization., Results: Two hundred thirty-six patients had complete endoscopic, pathologic, and operative records. Colonoscopy was inaccurate for tumor localization in 49 cases (21%). In 27 (11%) of these cases, a different procedure was required than initially planned; in an additional 10 cases (4%), the surgical approach required modification. Inaccurate localization was associated with previous colorectal procedures on both univariate analysis (odds ratio, 3.94; 95% confidence interval, 1.50-10.32; P<.005) and multivariate analysis (odds ratio, 4.47; 95% confidence interval, 1.64-12.08; P = .003). Having the colonoscopy performed by a surgeon trended toward protection from error on multivariate analysis (odds ratio, 0.47; 95% confidence interval, 0.20-1.08; P = .07). Age, sex, diverticular disease, endoscopist volume and years of training, and bowel preparation had no significant effect., Conclusions: Colonoscopy has a considerable error rate for localization of colorectal cancer, especially when previous colorectal procedures have been performed. Adjunctive localizing techniques, such as endoscopic tattooing, should be strongly considered.

Systems of trauma care in urban areas have a demonstrated survival benefit. Little is known of the benefit of trauma system organization in rural areas. We hypothesized that examination of all trauma deaths during a 1-year period would provide opportunities to improve care in our rural state. We used a medical examiner database of trauma deaths occurring during a 1-year period. Five board-certified surgeons analyzed deaths as preventable (P), potentially preventable (PP), and non-preventable (NP) using modified Delphi technique. There were 223 trauma deaths during a 1-year period. Most (63%) died at the scene prior to any medical intervention. Adjudication of the deaths demonstrated 5 P (2%; 95% CI 1-5%), 36 PP (16%; 95% CI 12-27%), and 179 NP (81%; 95% CI 76-86%). Agreement among trauma surgeons was only moderate with a k of 0.46. Suicide accounted for a significant number of the overall trauma deaths at 32 per cent. Rural trauma system design should focus on discovery, as that is where the majority of deaths occur. Suicide is a significant problem in this rural state that should be aggressively targeted with prevention programs.

Study Objective: Off-pump coronary artery bypass graft (CABG) surgery has been recently reintroduced into clinical practice. In light of the relatively low level of experience of most cardiac surgeons with off-pump CABG surgery, and the exceptional technical challenge of working on a "beating heart," off-pump CABG surgery presents a unique opportunity to explore the effect of surgeon case volume on surgical outcome after controlling for the effects of patient case mix and hospital volume., Design: A retrospective cohort study analyzing the association between surgeon volume and in-hospital mortality rate for off-pump and on-pump CABG surgery using random-effects logistic regression modeling., Setting and Patients: The analyses were based on the New York State clinical CABG surgery registry. The study sample consisted of 36,930 patients undergoing isolated CABG surgery between 1998 and 1999 that was performed by 181 surgeons at 33 hospitals., Interventions: None., Results: There is no association between the number of CABG procedures performed off-pump by an individual surgeon and in-hospital mortality rates (p = 0.93) after controlling for hospital CABG surgery volume and patient-level risk factors. There is also no association between the off-pump CABG surgery mortality rate and the total number of both off-pump and on-pump CABG surgery cases (p = 0.78). In the on-pump CABG surgery cohort, surgeons performing a high volume of CABG procedures had significantly lower risk-adjusted mortality rates among their patients compared to those performing a very low volume, a low-volume, and a medium volume of CABG procedures (p < 0.006)., Conclusion: For off-pump CABG surgery, surgeons performing a high volume of procedures do not have better mortality outcomes than those performing a low volume of procedures. However, higher surgeon case volumes are associated with lower mortality rates for on-pump CABG surgery. The absence of a volume-outcome association for off-pump CABG surgery is especially surprising in light of the more technically demanding nature of off-pump CABG surgery compared to on-pump CABG surgery.

Purpose: Local excision is a commonly used technique for many benign and selected malignant rectal lesions. Compared with radical resection, it is associated with decreased morbidity and mortality and improved functional results. Transanal endoscopic microsurgery is gaining popularity because of its ability to access the upper rectum and its precise excision techniques. However, the functional consequences have not been extensively studied., Methods: All patients subject to transanal endoscopic microsurgery prospectively completed preoperative and postoperative (6 weeks) surveys including Fecal Incontinence Severity Index, Fecal Incontinence Quality of Life, number of bowel movements per 24 hours, and ability to defer defecation. All data were collected by an independent research coordinator. Demographics, operative details, and complications were also collected prospectively., Results: Forty-one patients successfully underwent transanal endoscopic microsurgery. Fourteen patients had malignant lesions and 27 had benign lesions. Two patients required abdominoperineal resection based on postoperative diagnosis. Thirty-nine patients have completed follow-up and were available for review. Mean length of surgery was 64 minutes and length of stay was 0.9 day. Average distance from the anal verge to the proximal tumor margin was 11.4 cm and mean tumor size was 8.75 cm. Twenty-three patients had full-thickness excision with primary closure, ten had full-thickness excision without closure, five had partial-thickness excision, one had an excision of a mass in the anovaginal septum, and one had resection of an anastomotic stricture. Each patient served as his own control. Preoperative and postoperative number of bowel movements per 24 hours were 2.0 and 2.0, respectively. Preoperative vs. postoperative urgency (ability to defer defecation less than ten minutes) was unchanged. Mean preoperative and postoperative Fecal Incontinence Severity Index scores were 2.4 (range, 0-43) and 2.4 (range, 0-17), respectively (higher scores indicate worse function). In addition, the four parameters measured by the Fecal Incontinence Quality of Life survey were unchanged when preoperative and postoperative data were compared., Conclusions: Transanal endoscopic microsurgery allows precise excision of tumors throughout the rectum. However, it involves inserting a 40-mm-diameter operating proctoscope and significant operating times. Despite this, as measured by ability to defer defecation, number of bowel movements per 24 hours, Fecal Incontinence Severity Index, and Fecal Incontinence Quality of Life survey, transanal endoscopic microsurgery has no detrimental affect on fecal continence.

Context: The Major Trauma Outcome Study (MTOS) database was created by the American College of Surgeons over 20 years ago to establish national norms for trauma care. The primary trauma outcome prediction models used for evaluating the quality of trauma care, TRISS and ASCOT (A Severity Characterization of Trauma), were developed using the MTOS database., Objective: First, to determine whether TRISS and ASCOT agree on hospital quality. Second, to determine whether TRISS and ASCOT accurately reflect contemporary outcomes in trauma care., Design, Setting and Patients: A retrospective cohort study based on 91,112 patients admitted to 69 hospitals between 2000 and 2001 in the National Trauma Databank. Using TRISS and ASCOT, the ratio of the observed to expected mortality rate (O/E ratio) was calculated for each hospital. Hospitals whose O/E ratio was statistically different from 1 were identified as quality outliers. Kappa analysis was used to assess the degree to which TRISS and ASCOT agreed on the identity of hospital quality outliers., Results: TRISS and ASCOT disagreed on the outlier status of 35 of the 69 hospitals. Kappa analysis revealed only fair agreement (kappa = 0.23; p = 0.0015) between TRISS and ASCOT in identifying quality outliers. Thirty-eight hospitals were identified by the TRISS method as high-performance hospitals., Conclusion: First, TRISS and ASCOT exhibit substantial disagreement on the identity of quality outliers within the NTDB. Second, an unrealistically high number of hospitals were identified as high-performance outliers using either TRISS or ASCOT. These findings have important implications for the use of TRISS and ASCOT for benchmarking performance and quality improvement.

Introduction: Slow healing of ulcers in chronic venous insufficiency (CVI) has long been thought secondary to venous hypertension. Dermal fibroblasts isolated from venous ulcers have morphologies and protein production suggestive of premature aging. In this study, we hypothesized that neonatal fibroblasts (NNF) cultured under elevated pressure will demonstrate premature aging and that this effect will be augmented by an inflammatory mediator, transforming growth factor beta (TGF-beta)., Materials and Methods: A unique pressure incubator was used to culture NNF at atmospheric pressure (ATM), ATM + 30 mmHg, ATM + 60 mmHg, and ATM +120 mmHg. Some pressure-exposed NNF were also cultured with TGF- beta (1 ng/ml). Growth rates were determined by flow cytometry. Senescent cells were identified by staining with a marker for cellular senescence, beta-galactosidase (SA-beta-Gal). Light microscopy and digital imaging were used to evaluate cell morphology. Paired linear models and comparison of the slopes were used for statistical analysis of growth. chi2 analysis was used to compare senescence rates., Results: NNF cultured at ATM + 60 mmHg and ATM + 120 mmHg showed increased SA-beta-Gal activity (P <0.05), and reduced growth rates (P <0.05) at 11 days. These effects were not seen at ATM + 30 mmHg. NNF grown with TGF-beta did not show augmented SA-beta-Gal staining., Conclusions: Pressure-exposed NNF demonstrated an accelerated aging phenomenon similar to fibroblasts isolated from venous ulcers. This aging effect was directly related to the level of pressure. TGF-beta did not augment the aging effect. This study suggests that pressure elevations result in altered cell function and accelerated aging that may contribute to the slowed healing seen in patients with venous insufficiency.

Purpose: The purpose of this study was to assess the safety of subtotal colectomy and outcomes after this procedure in the modern era of immunosuppressive agents and primary pelvic pouch surgery., Methods: All patients undergoing subtotal colectomy with ileostomy for ulcerative colitis or Crohn's colitis from July 1, 1990 to June 30, 2003 were identified from a prospective database. Only patients who were operated on while hospitalized for disease exacerbation were included in the analysis. Age at colectomy, preoperative days in the hospital, postoperative length of stay, and complications were recorded. The medical records were then reviewed for duration of disease, preoperative diagnosis, use of steroids and immunomodulators, parenteral nutrition, endoscopy findings, albumin level, postoperative diagnosis, and ultimate disposition., Results: One hundred one patients underwent subtotal colectomy for inflammatory bowel disease during the study period. Seventy-four patients met all the inclusion criteria. The mean age was 35.9 (range, 18-86) years. Median duration of disease was 36 (0-240) months, but 28 patients had colitis for less than 1 year, whereas 10 patients had disease of greater than 10 years duration at the time of colectomy. Median preoperative hospital stay was 7 (range, 0-43) days and median postoperative length of stay was 6.5 (range, 4-37) days. Sixty-six patients underwent surgery for refractory exacerbation, 5 for free perforation, 2 for abscess, and 1 patient for hemorrhage. Twenty-seven patients (36.5 percent) had a change in diagnosis after surgery. Complications occurred in 17 patients (23 percent), including 8 cases of central venous catheter-associated thrombosis; 7 of these occurred in patients who had been hospitalized for more than a week before surgery. In the ulcerative colitis patients, 31 of 52 ultimately underwent ileal pouch-anal anastomosis, but 20 (39 percent) chose either completion proctectomy or no further surgery., Conclusions: Subtotal colectomy with ileostomy remains a safe and effective treatment for patients requiring urgent surgery for severe inflammatory bowel disease. Because of the substantial incidence of change in diagnosis and satisfaction in many patients with an ileostomy, subtotal colectomy with ileostomy may be preferable to primary ileal pouch-anal anastomosis, even when a pouch is considered safe.

Background: Proton pump inhibitors (PPI) may increase the risk of nosocomial pneumonia caused by profound irreversible gastric acid suppression. The study purpose was to characterize differences in nosocomial pneumonia and related infections in trauma patients administered either histamine2-receptor antagonists (H2RA) or PPI., Methods: Observational evaluation of consecutive critically ill adult trauma patients administered either omeprazole or famotidine during a 22-month period. Nosocomial infection was evaluated daily based on published CDC definitions., Results: Eighty of 269 patients fulfilled study criteria. The PPI group (n = 40) exhibited increased baseline risk for infection, demonstrated by higher ISS (p = 0.020), more chest tube placements (p = 0.031), and increased chest trauma (p = 0.025). Overall number of patients infected per group included 33% and 40% of patients administered PPI and H2RA, respectively (p = 0.64). Despite baseline differences, the incidence of nosocomial infection was similar (p = 0.87), and extrapolation of pneumonia based on 1000 patient days revealed a ratio 51.7 vs 52.2 in the PPI vs H2RA groups, respectively, which was not significant (p = 0.99)., Conclusions: Proton pump inhibitor administration does not increase risk of nosocomial pneumonia or other nosocomial infections compared with H2RA therapy in the critically ill trauma patient.

Objective: The Injury Severity Score (ISS) is widely used for anatomic severity assessments. The ISS is the sum of the squares of a patient's three worst Abbreviated Injury Scale (AIS) severities (1-6) from three specified body regions. The set of three AIS severities (including 0s) is called a "triplet." ISS values of 9, 17, 18, 25, 26, 27, 29, 33, 34, 41, and 50 can originate from two unique triplets, but it is not clear whether the mortalities of the triplets are equal. A related question regards the monotonicity of the ISS, that is, whether mortality increases with successive values of ISS. This study sought to compare the mortality of equivalent ISS values from different triplets and to evaluate whether ISS is a monotonic function of mortality., Methods: The ISS, its corresponding three-digit triplet, and the ICISS (an International Classification of Diseases, Ninth Revision-based competing score) were calculated for 361,381 National Trauma Data Bank patients. Fisher's exact tests were used to test for mortality differences between triplets that yield the same ISS. Plots of mortality by score value were produced to visually assess the monotonicity of the ICISS and the ISS., Results: Six of the 11 triplet pairs had mortalities that differed by greater than 20%, with the largest difference being 32% for an ISS of 25 (triplets 0, 0, 5 and 0, 3, 4). Two other values (9 and 17) have triplet pairs whose mortality differences are less but still statistically different. The ISS is markedly nonmonotonic and is characterized by large spikes in mortality for successive ISS values. Plots of the ICISS show it to be largely monotonic., Conclusion: The ISS is a nonmonotonic, triplet-dependent function of mortality. Those who persist in using the ISS to describe populations or make risk adjustments should do so cautiously, being sure to account for triplet type. These suspect ISS values appear in approximately 25% of cases.

Background: The Trauma and Injury Severity Score (TRISS) methodology was developed to predict the probability of survival after trauma. Despite many criticisms, this methodology remains in common use. The purpose of this study was to show that improving the stratification for age and adding an adjustment for comorbidity significantly increases the predictive accuracy of the TRISS model., Methods: The trauma registry and the hospital administrative database of a regional trauma center were used to identify all blunt trauma patients older than 14 years of age admitted with International Classification of Diseases, Ninth Revision codes 800 to 959 from April 1993 to March 2001. Each individual medical record was then reviewed to ascertain the Revised Trauma Score, the Injury Severity Score, the age of the patients, and the presence of eight comorbidities. The outcome variable was the status at discharge: alive or dead. The study population was divided into two subsamples of equal size using a random sampling method. Logistic regression was used to develop models on the first subsample; a second subsample was used for cross-validation of the models. The original TRISS and three TRISS-derived models were created using different categorizations of Revised Trauma Score, Injury Severity Score, and age. A new model labeled TRISSCOM was created that included an additional term for the presence of comorbidity., Results: There were 5,672 blunt trauma patients, 2,836 in each group. For original TRISS, the Hosmer-Lemeshow statistic (HL) was 179.1 and the area under the receiver operating characteristic (AUROC) curve was 0.873. Sensitivity and specificity were 99.0% and 27.8%, respectively. For the best modified TRISS model, the HL statistic was 20.35, the AUROC curve was 0.902, the sensitivity was 99.0%, and the specificity was 27.8%. For TRISSCOM, the HL statistic was 14.95 and the AUROC curve was 0.918. Sensitivity and specificity were 99.0% and 29.7%, respectively. The difference between the two models almost reached statistical significance (p = 0.086). When TRISSCOM was applied to the cross-validation group, the HL statistic was 10.48 and the AUROC curve was 0.914. The sensitivity was 98.6% and the specificity was 34.9%., Conclusion: TRISSCOM can predict survival more accurately than models that do not include comorbidity. A better categorization of age and the inclusion of comorbid conditions in the logistic model significantly improves the predictive performance of TRISS.

Background: Regionalization of trauma care services aims to improve outcomes by limiting trauma care delivery to a select group of dedicated trauma centers. However, the evidence linking trauma center volume and outcome is not conclusive. The objective of this study was to examine the volume-mortality relation for patients with severe trauma in the National Trauma Databank., Methods: This study was based on data for adult patients 18 years of age or older in the National Trauma Databank with an Injury Severity Score (ISS) of 15 or more who sustained either blunt or penetrating trauma. The main outcome measure was in-hospital survival as a function of trauma center volume. Logistic regression modeling was used to analyze the relation between survival and hospital volume for patients sustaining either severe blunt or severe penetrating trauma., Results: For the blunt trauma cohort, model diagnostics showed that the single highest-volume center was an outlier. After exclusion of the patients from this center, no association could be demonstrated between trauma volume and outcome (p = 0.465) for blunt trauma. A separate multivariate analysis of patients with penetrating trauma also could not demonstrate a significant volume-mortality association (p = 0.919). Both regression models exhibited excellent discrimination and acceptable calibration., Conclusion: The findings of this study do not support the position that higher trauma center volumes are associated with improved survival. The implication of this study is that the hospital volume criteria established by the American College of Surgeons may need to be reexamined.

Background: Trauma centers routinely benchmark their survival outcomes against a national norm using the TRISS methodology. However, the use of survival as a measure of the effectiveness of trauma care may be too limited in scope because it fails to capture information regarding functional outcomes., Methods: The objective of this study was to develop a prediction model that allows hospitals to benchmark their functional outcomes in blunt trauma patients, and to determine whether the assessment of hospital "quality" depends on the choice of outcome measure: survival or survival combined with functional outcome. This retrospective cohort study was based on patients, aged 18 years or older, in the National Trauma Database who sustained blunt trauma in 1999 without associated head or spinal cord injury. We developed a sequential logistic model to predict the probability of a good functional outcome. The TRISS methodology was customized to this data set to obtain a survival model. Using each of these prediction models, we then obtained two standardized measures of hospital performance: one based on the number of survivors and the other based on the number of survivors with good functional outcomes. These standardized outcome measures were then used to identify low-performance and high-performance hospitals. The ranking based on these two different measures were compared., Results: Fifteen of the 27 hospitals in the study cohort were categorized differently when their performance was benchmarked using survival versus functional outcome. Kappa analysis revealed minimal agreement between these two quality measures on the identity of hospital quality outliers (kappa = 0.04; p = 0.35)., Conclusion: The evaluation of hospital quality depends on whether hospital performance is judged by looking at survival or at survival combined with functional outcome. Because functional status is an important outcome of major concern to survivors, it is important to include it in hospital performance assessment. Consideration should be given to including functional outcome in the evaluation of trauma center performance.

Objective: To determine whether hierarchical modeling agrees with conventional logistic regression modeling on the identity of ICU quality outliers within a large multi-institutional database., Design: Retrospective database analysis., Setting and Patients: Subset of the Project IMPACT database consisting of 40435 adult patients admitted to surgical, medical, and mixed surgical-medical ICUs ( n=55) between 1997 and 1999 who met inclusion criteria for SAPS II., Measurements and Results: The SAPS II score was customized to this database using conventional logistic regression and using a hierarchical (random coefficients) model. Both models exhibited excellent discrimination ( Cstatistic) and calibration (Hosmer-Lemeshow statistic). The hierarchical and nonhierarchical models had C statistics of.870 and.865, and HL statistics of 3.71 ( p>.88, df=8) and 8.94 ( p>.35, df=8), respectively. Since the random effects component of the hierarchical model accounts for between-hospital variability, only the fixed-effects coefficients were used to calculate the expected mortality rate based on the hierarchical model. The ratio and 95% confidence intervals of the observed to expected mortality rate were calculated using both models for each ICU. ICUs whose observed/expected ratio was either less than 1 or greater than 1, and whose 95% confidence interval did not include 1 were labeled as either high-performance or low-performance outliers, respectively. Analysis using kappa statistic revealed almost perfect agreement between the two models (nonhierarchical vs. hierarchical) on the identity of ICU quality outliers., Conclusions: Models obtained by customizing SAPS II using a nonhierarchical and a hierarchical approach exhibit excellent agreement on the identity of ICU quality outliers.

Background: The International Classification of Diseases, Ninth Revision Injury Severity Score (ICISS) is criticized because it relies on survival risk ratios (SRRs) that are contaminated by incidents with multiple injuries. An SRR for an International Classification of Diseases, Ninth Revision code is the number of patients who survive the injury divided by the number who display it. The ICISS is the product of SRRs that correspond to a patient's injuries. Traditional SRRs are derived from databases that include patients with multiple injuries and are biased toward mortality, making them nonindependent. Independent SRRs are derived from incidents where patients sustained only an isolated injury. The objective of this study is to compare the mortality prediction abilities of independent and traditional SRRs via the ICISS., Methods: A 10-fold cross-validation design was used to estimate independent and traditional SRRs and their resulting ICISSs from 192,347 National Trauma Data Bank patients. Logistic regression modeled the scores as a function of mortality. The area under the receiver operating characteristic curve measured discrimination. Model fit was measured with the Akaike information criterion, a deviance statistic (lower is better). R2 values were compared to determine which score explained the most variance., Results: The independent ICISS statistically outperforms the traditional ICISS., Conclusion: Traditional SRRs used by the ICISS produce less accurate estimates of mortality than independent SRRs. The ICISS can be calculated in 97.9% of incidents using independent SRRs.

Purpose: Venous hypertension leads to venous stasis ulcers. White cell activation, protein leakage from pressurized capillaries, and cytokine imbalances have all been implicated as indirect effects of venous hypertension that contribute to dermal changes seen in chronic venous insufficiency. The direct effect of increased tissue pressures on dermal elements has not been investigated. Prior studies have shown that fibroblasts isolated from venous ulcers have altered growth rates, morphologies, and protein production similar to senescent or aged fibroblasts. We hypothesize that neonatal fibroblasts (NNFs) cultured in conditions of increased atmospheric pressure will demonstrate altered cell function when compared with those grown at normal atmospheric pressure (ATM)., Methods: A pressure incubator was used to culture populations of NNFs at ATM, 60 mm Hg over ATM (ATM + 60 mm Hg), and 120 mm Hg over ATM (ATM + 120 mm Hg). NNF population growth rates were determined by periodic flow cytometry analysis over a 2-week period. Light microscopy and digital imaging were used to evaluate cell morphology. Senescence-associated B-galactosidase (SA-beta-Gal) activity was determined using the X-Gal stain. Fibronectin production was assessed by exposing cells sequentially to anti-fibronectin antibodies and Oregon Green-conjugated goat anti-mouse secondary antibodies. Flow cytometry then was used to determine relative proportions of cells staining positively for fibronectin. Statistical analysis was accomplished with analysis of variance., Results: Populations of cells grown under increased pressures (both ATM + 60 and ATM + 120) showed reduced growth rates (P <.001). Similarly, morphologies of cells grown under pressure had increased cytoplasm to nuclear ratios with abnormal nuclear shapes. Populations of cells grown under pressure had higher percentages of cells staining positive for fibronectin (ATM = 45%, ATM + 60 = 59%, ATM + 120 = 79%). After 14 days of growth under pressure, fibroblast populations did not demonstrate augmented productions of the senescence marker SA-beta-Gal (ATM =.5%, ATM + 60 =.25%, ATM + 120 =.75%)., Conclusions: This study demonstrated that NNFs grown in culture under increased pressures undergo a transformation not seen in cells grown at atmospheric pressure. Cells grown under pressure demonstrated reduced growth rates, increased fibronectin production, and abnormal morphologies similar to fibroblasts isolated from venous ulcers. This study suggests that pressure elevations (like venous hypertension) can directly result in altered cell function and morphology that may contribute to the delayed wound healing seen in patients with venous ulcers. This model uses a pressurized incubator that may prove to be a valuable adjunct in studying the effects of venous hypertension.

Background: Survival risk ratios (SRRs) are database-specific point estimates of survival associated with each injury International Classification of Diseases, Ninth Revision (ICD-9) code. They are derived for each injury code by dividing the number of patients who survive the code by the total number of patients that display the code. SRRs are used to measure injury severity and distribution and are most prominently featured in the ICD-9 Injury Severity Score (ICISS), which is the product of a patient's SRRs. Because SRRs are important for trauma scoring, it is important that they be derived from a representative trauma population. The purpose of this study was to compare a new set of SRRs derived from the National Trauma Data Bank (NTDB) with SRRs derived years ago from the North Carolina Hospital Discharge Database (NCHDD)., Methods: Tests for differences of proportions were applied to determine which ICD-9 codes have significantly different SRRs in an attempt to characterize the database differences. Two different ICISSs were calculated for 170,853 eligible patients using the two different sets of SRRs, NCHDD and NTDB. The NTDB SRRs were calculated and applied using a 10-fold cross-validation to avoid bias in estimation. Estimates of discrimination for both ICISSs were calculated using the area under the receiver-operating characteristic curve. R2 and Akaike information criterion statistics were compared., Results: A modest statistical case is made for using the NTDB SRRs rather than the NCHDD SRRs., Conclusion: Researchers should begin using the NTDB SRRs for their outcome modeling and for ICISS calculation.

Background: There is evidence to support the existence of an inverse relation between mortality after coronary artery bypass graft (CABG) surgery and procedure volume. It is unclear whether all patients benefit equally from having CABG surgery performed at high-volume centers. The objective of this study was to determine whether the volume-outcome association for CABG surgery is modified by patient risk., Methods: This retrospective cohort analysis was conducted using data from the Cardiac Surgery Reporting System database on all patients (20,078) undergoing CABG surgery in New York State who were discharged in 1996. The main outcome measure was in-hospital mortality as a function of procedure volume after adjusting for severity of disease. Logistic regression modeling was used to explore the interaction between patient risk and procedure volume., Results: There is a significant interaction between procedure volume and patient risk (p = 0.01). The final model exhibits excellent discrimination (C statistic = 0.818) and goodness-of-fit (Hosmer-Lemeshow statistic = 6.02; p = 0.645). Very low (<0.5%) and low-risk (0.5%-2.0%) patients exhibit a greater reduction in CABG mortality than high (5.0%-10.0%) and very high risk (>10%) patients at high-volume centers relative to low-volume centers. Among the highest risk patients (>25% risk of mortality), higher risk patients have better outcomes at higher volume centers., Conclusions: For the vast majority of patients, low-risk patients benefit significantly more than high-risk patients from undergoing CABG surgery at high-volume centers instead of at low-volume centers. Low-risk patients benefit significantly more than high-risk patients from undergoing CABG surgery at high-volume centers instead of at low-volume centers. However, before generalizing these findings to other states, this study should be repeated using other regional population-based clinical databases.

Background: The prediction of outcome after injury must incorporate measures of injury severity, but there is no consensus on how many injuries should be used in calculating these measures. Initially, the single worst injury was used to predict outcome, but the introduction of the Injury Severity Score allowed up to three injuries to contribute to outcome prediction. Subsequently, other outcome prediction approaches used many (New Injury Severity Score [NISS]) or all (ICISS and Trauma Registry Abbreviated Injury Scale Score [TRAIS], which use International Classification of Diseases, Ninth Revision [ICD-9] and Abbreviated Injury Scale [AIS] survival risk ratios [SRRs], respectively) of a patient's injuries. The ability of only the most severe injury in predicting mortality has never been studied. Our objective was to determine the ability of a patient's worst injury to predict mortality., Methods: A 10-fold cross-validation design was used to compute six scores for each of 160,208 patients from a large trauma database (the National Trauma Data Bank [NTDB]). The scores were ICISS, TRAIS, ICISS1 (only a patient's worst ICD-9 SRR), TRAIS1 (only a patient's worst AIS SRR), NISS (sum of squares of worst three AIS severity measures), and MAXAIS (worst AIS severity measure). Discrimination was assessed using the area under the receiver operating characteristic curve. Logistic regression R2 gauged the proportion of variance each score explained. The Akaike information criterion, a deviance statistic (lower is better), assessed model fit., Results: The receiver operating characteristic curve, R2, and Akaike information criterion statistics (NC&#95;ICISS and NC&#95;ICDSRR1 represents scores derived from the original North Carolina Hospital Discharge Database SRRs) are summarized in tabular form in the Results section., Conclusion: Regardless of scoring type (ICD/AIS SRRs or AIS severity), a patient's worst injury discriminates survival better, fits better, and explains more variance than currently used multiple injury scores.

Background: The Glasgow Coma Scale (GCS) has served as an assessment tool in head trauma and as a measure of physiologic derangement in outcome models (e.g., TRISS and Acute Physiology and Chronic Health Evaluation), but it has not been rigorously examined as a predictor of outcome., Methods: Using a large trauma data set (National Trauma Data Bank, N = 204,181), we compared the predictive power (pseudo R2, receiver operating characteristic [ROC]) and calibration of the GCS to its components., Results: The GCS is actually a collection of 120 different combinations of its 3 predictors grouped into 12 different scores by simple addition (motor [m] + verbal [v] + eye [e] = GCS score). Problematically, different combinations summing to a single GCS score may actually have very different mortalities. For example, the GCS score of 4 can represent any of three mve combinations: 2/1/1 (survival = 0.52), 1/2/1 (survival = 0.73), or 1/1/2 (survival = 0.81). In addition, the relationship between GCS score and survival is not linear, and furthermore, a logistic model based on GCS score is poorly calibrated even after fractional polynomial transformation. The m component of the GCS, by contrast, is not only linearly related to survival, but preserves almost all the predictive power of the GCS (ROC(GCS) = 0.89, ROC(m) = 0.87; pseudo R2(GCS) = 0.42, pseudo R2(m) = 0.40) and has a better calibrated logistic model., Conclusion: Because the motor component of the GCS contains virtually all the information of the GCS itself, can be measured in intubated patients, and is much better behaved statistically than the GCS, we believe that the motor component of the GCS should replace the GCS in outcome prediction models. Because the m component is nonlinear in the log odds of survival, however, it should be mathematically transformed before its inclusion in broader outcome prediction models.

Background: A Level I trauma center must provide immediate availability general (trauma) surgical expertise. In the current practice few patients require a general surgical procedure. The expertise of subspecialists may also be required and frequently these patients will require subspecialty operative care. We hypothesized that trauma surgeons would receive less reimbursement than their subspecialty colleagues despite a greater commitment of time and effort in taking care of the multiply-injured patient., Methods: Three fellowship trained trauma surgeons were specifically hired to cover the trauma service for the year 2000. Professional billings, contribution to margin (reimbursement minus direct costs) of the trauma surgeons and subspecialists were obtained from the hospital financial information system. A surrogate for effort was assessed by the number of attending notes in the chart. A surrogate for complexity of care was assessed by the length of notes in the chart. Weekly time sheets assessed the percentage of time involved in the care of trauma patients., Results: There were 344 patients cared for exclusively on the trauma service for the year 2000. The billing generated per patient was $1005 for the trauma surgeon, $5904 for the subspecialists, and $27,554 for the hospital. Orthopedics and radiology generated more professional billing on the trauma patients than the trauma surgeons. The trauma surgeons spent 52% of their weekly clinical activity in the care of trauma patients, yet this activity accounted for only 16% of their billings (the rest came from general surgery and ICU care). The effort and complexity of care provided by the trauma surgeons was significantly greater than the subspecialists., Conclusion: The Level I trauma service is a conduit for patients coming into the hospital that provides a significant remuneration to the subspecialty services. Trauma surgeons are able to bill much less than many of their subspecialty colleagues despite expending significantly greater amounts of time and effort in the care of these patients. Strategies for improved reimbursement for trauma surgeons must be devised or trauma surgery will suffer the same fate as other areas of surgery, losing our brightest and best to more financially sound subspecialty services such as radiology and orthopedics.

Background: TRISS has reigned as the preeminent trauma outcome prediction model for 20 years. Despite this endorsement, the calibration of TRISS has been poor in most data sets where it has been examined. We hypothesized that the lack of calibration of TRISS was because of the inappropriate mathematical specification of the model that TRISS is based on, rather than the predictors in the model. In particular, we hypothesized that the nonlinearity of the Injury Severity Score (ISS) in the log odds of death was responsible for the poor calibration of TRISS, and further, that this nonlinearity could be corrected by the simple addition of an ISS squared term to the TRISS model., Methods: We examined ISS in the log odds of mortality for linearity in one large trauma data set, the National Pediatric Trauma Registry (NPTR) (n = 53,113 from 1985-1996; mortality, 1.3%); and two small data sets, the University of New Mexico (UNM) (n = 3,142 from 1991-1995; mortality, 8.6%) and Portland, Oregon (PORT) (n = 2,916 from 1990-1994; mortality, 1.75%). In addition, in the NPTR we compared the calibration of TRISS models with and without linearity in the log odds of death., Results: In the NPTR, ISS was profoundly nonlinear in the log odds of death for both blunt and penetrating trauma (p < 0.001). Moreover, the overall calibration of the TRISS model for the NPTR data was significantly improved when the nonlinearity of ISS was corrected by the addition of a quadratic ISS term as demonstrated by a 70% reduction (improvement) in the Hosmer-Lemeshow statistic. Interestingly, the addition of the ISS squared term did not affect the discrimination of the model. The log odds of survival in the UNM and PORT data sets were also better modeled when an ISS squared term was added (UNM, p = 0 0.052; PORT, p = 0.014), but improvements in the Hosmer-Lemeshow statistic were smaller, possibly because of the small size of these data sets., Conclusion: The TRISS model for outcome prediction currently uses ISS in a mathematically inappropriate way that impairs the calibration, but not the discrimination, of its predictions. If TRISS is to continue as the prediction standard for trauma, a quadratic ISS term must be added to the model. In the future, outcome prediction models should undergo thorough statistical modeling and evaluation before being released. Injury severity descriptors other than ISS (such as ASCOT, ICISS, or NISS) may require other modeling techniques to optimize the calibration of survival models that use these injury scores.

Objective: The purpose of this study was to compare the abilities of nine Abbreviated Injury Scale (AIS)- and (ICD-9)-based scoring algorithms in predicting mortality., Methods: The scores collected on 76,871 incidents consist of four AIS-based algorithms (Injury Severity Score [ISS], New Injury Severity Score, Anatomic Profile Score [APS], and maximum AIS [maxAIS]), their four ICD to AIS mapped counterparts, and the ICD-9-based ISS (ICISS). A 10-fold cross-validation was performed and area under the receiver operating characteristic curve was used to determine algorithm discrimination. Hosmer-Lemeshow statistics were computed to gauge goodness-of-fit, and model refinement measured variance of predicted probabilities., Results: Overall, the ICISS has the best discrimination and model refinement, whereas the APS has the best Hosmer-Lemeshow performance. ICD-9 to AIS mapped scores have worse discrimination than their AIS-based counterparts, but still show moderate performance., Conclusion: Differences in performance were relatively small. Complex scores such as the ICISS and the APS provide improvement in discrimination relative to the maxAIS and the ISS. Trauma registries should move to include the ICISS and the APS. The ISS and maxAIS perform moderately well and have bedside benefits.

Objective: Intensive care units (ICUs) use severity-adjusted mortality measures such as the standardized mortality ratio to benchmark their performance. Prognostic scoring systems such as Acute Physiology and Chronic Health Evaluation (APACHE) II, Simplified Acute Physiology Score II, and Mortality Probability Model II0 permit performance-based comparisons of ICUs by adjusting for severity of disease and case mix. Whether different risk-adjustment methods agree on the identity of ICU quality outliers within a single database has not been previously investigated. The objective of this study was to determine whether the identity of ICU quality outliers depends on the ICU scoring system used to calculate the standardized mortality ratio., Design, Setting, Patients: Retrospective cohort study of 16,604 patients from 32 hospitals based on the outcomes database (Project IMPACT) created by the Society of Critical Care Medicine. The ICUs were a mixture of medical, surgical, and mixed medical-surgical ICUs in urban and nonurban settings. Standardized mortality ratios for each ICU were calculated using APACHE II, Simplified Acute Physiology Score II, and Mortality Probability Model II. ICU quality outliers were defined as ICUs whose standardized mortality ratio was statistically different from 1. Kappa analysis was used to determine the extent of agreement between the scoring systems on the identity of hospital quality outliers. The intraclass correlation coefficient was calculated to estimate the reliability of standardized mortality ratios obtained using the three risk-adjustment methods., Measurements and Main Results: Kappa analysis showed fair to moderate agreement among the three scoring systems in identifying ICU quality outliers; the intraclass correlation coefficient suggested moderate to substantial agreement between the scoring systems. The majority of ICUs were classified as high-performance ICUs by all three scoring systems. All three scoring systems exhibited good discrimination and poor calibration in this data set., Conclusion: APACHE II, Simplified Acute Physiology Score II, and Mortality Probability Model II0 exhibit fair to moderate agreement in identifying quality outliers. However, the finding that most ICUs in this database were judged to be high-performing units limits the usefulness of these models in their present form for benchmarking.

Objective: To assess whether customized versions of the Simplified Acute Physiology Score (SAPS) II and the Mortality Probability Model (MPM) II0 agree on the identity of intensive care unit quality outliers within a multiple-center database., Design: Retrospective database analysis., Setting and Patients: Patient subset of the Project IMPACT database consisting of 39,617 adult patients admitted to surgical, medical, and mixed surgical-medical intensive care units at 54 hospitals between 1995 and 1999 who met inclusion criteria for SAPS II and MPM II0., Interventions: Customized versions of SAPS II and MPM II0 were obtained by fitting new logistic regressions to the data by using the risk score as the independent variable and outcome at hospital discharge as the dependent variable. The data set was divided randomly into a training set and a validation set. Each model was customized by using the training set; model performance was then assessed in the validation set by using the area under the receiver operating characteristic curve and the Hosmer-Lemeshow statistic. The final models were based on the entire data set. The level of agreement between the customized models on the identity of quality outliers was evaluated by using kappa analysis., Measurements and Main Results: Both customized models exhibited good discrimination and good calibration in this database. The area under the receiver operating characteristic curve was 0.83 for MPM II0 and 0.872 for SAPS II following model customization. The Hosmer-Lemeshow statistic was 12.3 ( >.14) for MPM II0, and 8.17 (p >.42) for SAPS II, after customization. Kappa analysis showed only fair agreement between the two customized models with regard to the identity of the quality outliers: kappa = 0.44 (95% confidence interval, 0.24, 0.65)., Conclusions: Customization of SAPS II and MPM II0 to the Project IMPACT database resulted in well-calibrated models. Despite this, the models exhibited only a moderate level of agreement in which hospitals were designated as quality outliers. Seventeen of the 54 hospitals were categorized differently depending on which of the two scoring systems was used. Therefore, the rating of quality of care appears, in part, to be a function of the prediction model used.