Turner M. Osler

Anastomotic Leaks After Intestinal Anastomosis: It's Later Than You Think

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.

Association between Intraoperative Blood Transfusion and Mortality and Morbidity in Patients Undergoing Noncardiac Surgery

Background:The impact of intraoperative erythrocyte transfusion on outcomes of anemic patients undergoing noncardiac surgery has not been well characterized. The objective of this study was to examine the association between blood transfusion and mortality and morbidity in patients with severe anemia (hematocrit less than 30%) who are exposed to one or two units of erythrocytes intraoperatively. Methods:This was a retrospective analysis of the association of blood transfusion and 30-day mortality and 30-day morbidity in 10,100 patients undergoing general, vascular, or orthopedic surgery. We estimated separate multivariate logistic regression models for 30-day mortality and for 30-day complications. Results:Intraoperative blood transfusion was associated with an increased risk of death (odds ratio [OR], 1.29; 95% CI, 1.03–1.62). Patients receiving an intraoperative transfusion were more likely to have pulmonary, septic, wound, or thromboembolic complications, compared with patients not receiving an intraoperative transfusion. Compared with patients who were not transfused, patients receiving one or two units of erythrocytes were more likely to have pulmonary complications (OR, 1.76; 95% CI, 1.48–2.09), sepsis (OR, 1.43; 95% CI, 1.21–1.68), thromboembolic complications (OR, 1.77; 95% CI, 1.32–2.38), and wound complications (OR, 1.87; 95% CI, 1.47–2.37). Conclusions:Intraoperative blood transfusion is associated with a higher risk of mortality and morbidity in surgical patients with severe anemia. It is unknown whether this association is due to the adverse effects of blood transfusion or is, instead, the result of increased blood loss in the patients receiving blood.

Improving the Glasgow Coma Scale score: motor score alone is a better predictor

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.

Hypertonic saline resuscitation of patients with head injury: a prospective, randomized clinical trial.

BACKGROUND Experimental and clinical work has suggested that hypertonic saline (HTS) would be better than lactated Ringers solution (LRS) for the resuscitation of patients with head injuries. No clinical study has examined the effect of HTS infusion on intracranial pressure (ICP) and outcome in patients with head injuries. We hypothesized that HTS infusion would result in a lower ICP and fewer medical interventions to lower ICP compared with LRS. METHODS/DESIGN Prospective, randomized clinical trial at two teaching hospitals. RESULTS Thirty-four patients were enrolled and were similar in age and Injury Severity Score. HTS patients had a lower admission Glasgow Coma Scale score (HTS: 4.7+/-0.7; LRS: 6.7+/-0.7; p = 0.057), a higher initial ICP (HTS: 16+/-2; LRS: 11+/-2; p = 0.06), and a higher initial mean maximum ICP (HTS: 31+/-3; LRS: 18+/-2; p < 0.01). Treatment effectively lowered ICP in both groups, and there was no significant difference between the groups in ICP at any time after entry. HTS patients required significantly more interventions (HTS: 31+/-4; LRS: 11+/-3; p < 0.01). During the study, the change in maximum ICP was positive in the LRS group but negative in the HTS group (LRS: +2+/-3; HTS: -9+/-4; p < 0.05). CONCLUSION As a group, HTS patients had more severe head injuries. HTS and LRS used with other therapies effectively controlled the ICP. The widely held conviction that sodium administration will lead to a sustained increase in ICP is not supported by this work.

Simplified Estimates of the Probability of Death After Burn Injuries: Extending and Updating the Baux Score

BACKGROUND : Generations of clinicians have used the Baux score, defined as the sum of age in years and percent body burn, to predict percent mortality after trauma, but advances in burn care have rendered the predictions of this score too pessimistic. Additionally, this score does not include the effects of inhalation injury. METHODS : We revised the Baux score to include inhalation injury and recalibrated its predictions using a single-term logistic regression model developed using data on 39,888 burned patients provided by the national burn repository. We compared this revised Baux score to a more complex logistic regression model derived from the same data set and predictors. RESULTS : A preliminary logistic regression model showed that age and percent burn contribute almost equally to mortality and further that the presence of inhalation injury added the equivalent of 17 years (or 17% burn). These observations suggested a revised Baux Score:Age + Percent Burn + 17 * (Inhalation Injury, 1 = yes, 0 = no)A logistic model based on the Revised Baux Score performed well, but a more complex model obtained using modern statistical model building tools had better discrimination and calibration. CONCLUSIONS : Our proposed revised Baux score is simple enough for mental calculation, and its inverse logit transformation (provided with a calculator or nomogram) can provide precise predictions of mortality. Better predictions can be obtained using our more complex statistical model. Burn surgeons and nurses accustomed to using the original Baux score may welcome an updated version.

Trauma in the elderly.

One hundred geriatric patients who suffered injury severe enough to necessitate hospitalization were compared retrospectively to a random group of 100 younger patients. The elderly suffered different types of injury and died six times as often as their younger peers, even when controlled for injury severity. The PRE method was employed to examine outcome in both groups and was found to be strongly predictive of death in young patients. Age stratification aided significantly in predicting mortality in elderly patients. Regression analysis was employed to examine the data set to determine the relative importance of several variables in the prediction of ultimate mortality. By incorporating all the data from the entire data set, curves describing the contribution of age and shock to mortality corrected for all factors is possible. Increasing age after 65 increases mortality and this effect is dramatically increased by the presence of shock. This information may be useful in counselling the injured elderly and their families.

The Surgical Mortality Probability Model: derivation and validation of a simple risk prediction rule for noncardiac surgery.

Objective:To develop a 30-day mortality risk index for noncardiac surgery that can be used to communicate risk information to patients and guide clinical management at the “point-of-care,” and that can be used by surgeons and hospitals to internally audit their quality of care. Background:Clinicians rely on the Revised Cardiac Risk Index to quantify the risk of cardiac complications in patients undergoing noncardiac surgery. Because mortality from noncardiac causes accounts for many perioperative deaths, there is also a need for a simple bedside risk index to predict 30-day all-cause mortality after noncardiac surgery. Methods:Retrospective cohort study of 298,772 patients undergoing noncardiac surgery during 2005 to 2007 using the American College of Surgeons National Surgical Quality Improvement Program database. Results:The 9-point S-MPM (Surgical Mortality Probability Model) 30-day mortality risk index was derived empirically and includes three risk factors: ASA (American Society of Anesthesiologists) physical status, emergency status, and surgery risk class. Patients with ASA physical status I, II, III, IV or V were assigned either 0, 2, 4, 5, or 6 points, respectively; intermediate- or high-risk procedures were assigned 1 or 2 points, respectively; and emergency procedures were assigned 1 point. Patients with risk scores less than 5 had a predicted risk of mortality less than 0.50%, whereas patients with a risk score of 5 to 6 had a risk of mortality between 1.5% and 4.0%. Patients with a risk score greater than 6 had risk of mortality more than 10%. S-MPM exhibited excellent discrimination (C statistic, 0.897) and acceptable calibration (Hosmer-Lemeshow statistic 13.0, P = 0.023) in the validation data set. Conclusions:Thirty-day mortality after noncardiac surgery can be accurately predicted using a simple and accurate risk score based on information readily available at the bedside. This risk index may play a useful role in facilitating shared decision making, developing and implementing risk-reduction strategies, and guiding quality improvement efforts.

Transanal endoscopic microsurgery: a prospective evaluation of functional results.

PURPOSELocal 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.METHODSAll 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.RESULTSForty-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.CONCLUSIONSTransanal 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.

Rating the quality of intensive care units: is it a function of the intensive care unit scoring system?

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 II0. 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.

Do pediatric trauma centers have better survival rates than adult trauma centers? An examination of the National Pediatric Trauma Registry.

BACKGROUND Pediatric trauma centers (PTCs) were developed to improve the survival of injured children, but it is currently unknown if children admitted to PTCs are more likely to survive than those admitted to adult trauma centers (ATCs). METHODS Fifty-three thousand one hundred thirteen pediatric trauma cases from 22 PTCs and 31 ATCs included in the National Pediatric Trauma Registry were reviewed to evaluate survival rates at PTCs and ATCs. RESULTS Overall, 1,259 children died. The raw mortality rate was lower at PTCs (1.81% of 32,554 children) than at ATCs (3.88% of 18,368 children). However, patients admitted to ATCs were more severely injured. When Injury Severity Score, Pediatric Trauma Score, mechanism (blunt or penetrating), gender, age, clustering, and American College of Surgeons (ACS) verification status were controlled for using a single logistic regression model, there was no statistically significant difference in survival between PTCs and ATCs (odds ratio, 1.02; 95% confidence interval, 0.83-1.26; p = 0.587). A similar comparison of the 12 ACS-verified trauma centers with the 41 nonverified centers showed verification to be associated with improved survival (odds ratio, 0.75; 95% confidence interval, 0.58-0.97; p = 0.013). CONCLUSION Although PTCs have higher overall survival rates than ATCs, this difference disappears when the analysis controls for Injury Severity Score, Pediatric Trauma Score, age, mechanism, and ACS verification status. ACS-verified centers have significantly higher survival rates than do unverified centers.