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BACKGROUND: The Injury Severity Score (ISS) is widely used as a method for rating severity of injury. The ISS is the sum of the squares of the three worst Abbreviated Injury Scale (AIS) values from three body regions. Patients with penetrating injuries tend to have higher mortality rates for a given ISS than patients with blunt injuries. This is thought to be secondary to the increased prevalence of multiple severe injuries in the same body region in patients with penetrating injuries, which the ISS does not account for. We hypothesized that the mechanism-based difference in mortality could be attributed to certain ISS ranges and specific AIS values by body region. METHODS: Outcome and injury scoring data were obtained from transfused patients admitted to 23 Level I trauma centers. ISS values were grouped into categories, and a logistic regression model was created. Mortality for each ISS category was determined and compared with the ISS 1 to 15 group. An interaction term was added to evaluate the effect of mechanism. Additional logistic regression models were created to examine each AIS category individually. RESULTS: There were 2,292 patients in the cohort. An overall interaction between ISS and mechanism was observed (p = 0.049). Mortality rates between blunt and penetrating patients with an ISS between 25 and 40 were significantly different (23.6 vs. 36.1%; p = 0.022). Within this range, the magnitude of the difference in mortality was far higher for penetrating patients with head injuries (75% vs. 37% for blunt) than truncal injuries (26% vs. 17% for blunt). Penetrating trauma patients with an AIS head of 4 or 5, AIS abdomen of 3, or AIS extremity of 3 all had adjusted mortality rates higher than blunt trauma patients with those values. CONCLUSION: Significant differences in mortality between blunt and penetrating trauma patients exist at certain ISS and AIS category values. The mortality difference is greatest for head injured patients. Language: en

Background: The effect of blood component ratios on the survival of patients with traumatic brain injury (TBI) has not been studied. Methods: A database of patients transfused in the first 24 hours after admission for injury from 22 Level I trauma centers over an 18-month period was queried to find patients who (1) met different definitions of massive transfusion (5 units red blood cell [RBC] in 6 hours vs. 10 units RBC in 24 hours), (2) received high or low ratios of platelets or plasma to RBC units (1:2 vs. /=1:2), and (3) had severe TBI (head abbreviated injury score /=3) (TBI+). Results: Of 2,312 total patients, 850 patients were transfused with /= 5 RBC units in 6 hours and 807 could be classified into TBi+ (n = 281) or TBI- (n = 526). Six hundred forty-three patients were transfused with /=10 RBC units in 24 hours with 622 classified into TBI+ (n = 220) and TBi- (n = 402). For both high-risk populations, a high ratio of platelets:RBCs (not plasma) was independently associated with improved 30-day survival for patients with TBI+ and a high ratio of plasma:RBCs (not platelets) was independently associated with improved 30-day survival in TBI- patients. Conclusions: High platelet ratio was associated with improved survival in TBI+ patients while a high plasma ratio was associated with improved survival in TBI- patients. Prospective studies of blood product ratios should include TBI in the analysis for determination of optimal use of ratios on outcome in injured patients.

Background: Improvements in prehospital care and resuscitation have led to increases in the number of severely injured patients who are salvageable. Massive transfusion has been increasingly used. Patients often present with markedly abnormal physiologic and biochemical data. The purpose of this study was to identify objective data that can be used to identify clinical futility in massively transfused trauma patients to allow for early termination of resuscitative efforts. Methods: A multicenter database was used. Initial physiologic and biochemical data were obtained, and mortality was determined for patients in the 5th and 10th percentiles for each variable. Raw data from the extreme outliers for each variable were also examined to determine whether a point of excessive mortality could be identified. Injury scoring data were also analyzed. A classification tree model was used to look for variable combinations that predict clinical futility. Results: The cohort included 704 patients. Overall mortality was 40.2%. The highest mortality rates were seen in patients in the 10th percentile for lactate (77%) and pH (72%). Survivors at the extreme ends of the distribution curves for each variable were not uncommon. The classification tree analysis failed to identify any biochemical and physiologic variable combination predictive of 90% mortality. Patients older than 65 years with severe head injuries had 100% mortality. Conclusion: Consideration should be given to withholding massive transfusion for patients older than 65 years with severe head injuries. Otherwise we did not identify any objective variables that reliably predict clinical futility in individual cases. Significant survival rates can be expected even in patients with profoundly abnormal physiologic and biochemical data.

BACKGROUND Several recent military and civilian trauma studies demonstrate that improved outcomes are associated with early and increased use of plasma-based resuscitation strategies. However, outcomes associated with platelet transfusions are poorly characterized. We hypothesized that increased platelet:red blood cells (RBC) ratios would decrease hemorrhagic death and improve survival after massive transfusion (MT). METHODS A transfusion database of patients transported from the scene to 22 Level I Trauma Centers over 12 months in 2005 to 2006 was reviewed. MT was defined as receiving ≥ 10 RBC units within 24 hours of admission. To mitigate survival bias, 25 patients who died within 60 minutes of arrival were excluded from analysis. Six random donor platelet units were considered equal to a single apheresis platelet unit. Admission and outcome data associated with the low (>1:20), medium (1:2), and high (1:1) platelet:RBC ratios were examined. These groups were based on the median value of the tertiles for the ratio of platelets:RBC units. RESULTS Two thousand three hundred twelve patients received at least one unit of blood and 643 received an MT. Admission vital signs, INR, temperature, pH, Glasgow Coma Scale, Injury Severity Score, and age were similar between platelet ratio groups. The average admission platelet counts were lower in the patients who received the high platelet:RBC ratio versus the low ratio (192 vs. 216, p = 0.03). Patients who received MT were severely injured, with a mean (± standard deviation) Injury Severity Score of 33 ± 16 and received 22 ± 15 RBCs and 11 ± 14 platelets within 24 hours of injury. Increased platelet ratios were associated with improved survival at 24 hours and 30 days (p < 0.001 for both). Truncal hemorrhage as a cause of death was decreased (low: 67%, medium: 60%, high: 47%, p = 0.04). Multiple organ failure mortality was increased (low: 7%, medium: 16%, high: 27%, p = 0.003), but overall 30-day survival was improved (low: 52%, medium: 57%, high: 70%) in the high ratio group (medium vs. high: p = 0.008; low vs. high: p = 0.007). CONCLUSION Similar to recently published military data, transfusion of platelet:RBC ratios of 1:1 was associated with improved early and late survival, decreased hemorrhagic death and a concomitant increase in multiple organ failure-related mortality. Based on this large retrospective study, increased and early use of platelets may be justified, pending the results of prospective randomized transfusion data.

Background: Administration of high transfusion ratios in patients not requiring massive transfusion might be harmful. We aimed to determine the effect of high ratios of fresh frozen plasma (FFP) and platelets (PLT) to packed red blood cells (PRBC) in nonmassively transfused patients. Methods: Records of 1,788 transfused trauma patients who received 10 units of PRBC in 24 hours at 23 United States Level I trauma centers were reviewed. The relationship between ratio category (low and high) and in-hospital mortality was assessed with propensity-adjusted multivariate proportional hazards models. Results: At baseline, patients transfused with a high FFP:PRBC ratio were younger, had a lower Glasgow Coma Scale score, and a higher Injury Severity Score. Those receiving a high PLT:PRBC ratio were older. The risk of in-hospital mortality did not vary significantly with FFP:PRBC ratio category. Intensive care unit (ICU)-free days, hospital-free days, and ventilator-free days did not vary significantly with FFP:PRBC ratio category. ICU-free days and ventilator-free days were significantly decreased among patients in the high (1:1) PLT:PRBC category, and hospital-free days did not vary significantly with PLT:PRBC ratio category. The analysis was repeated using 1:2 as the cutoff for high and low ratios. Using this cutoff, there was still no difference in mortality with either FFP:PRBC ratios or platelet:PRBC ratios. However, patients receiving a 1:2 ratio of FFP: PRBCs or a 1:2 ratio PLT:PRBCs had significantly decreased ICU-free days and ventilator-free days. Conclusions: FFP:PRBC and PLT:PRBC ratios were not associated with in-hospital mortality. Depending on the threshold analyzed, a high ratio of FFP:PRBC and PLT:PRBC transfusion was associated with fewer ICU-free days and fewer ventilator-free days, suggesting that the damage control infusion of FFP and PLT may cause increased morbidity in nonmassively transfused patients and should be rapidly terminated when it becomes clear that a massive transfusion will not be required.

The term “evidence-based medicine” was first coined by Sackett and colleagues as “the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients.”1 The key to practising evidencebased medicine is applying the best current knowledge to decisions in individual patients. Medical knowledge is continually and rapidly expanding. For clinicians to practise evidence-based medicine, they must have the skills to read and interpret the medical literature so that they can determine the validity, reliability, credibility and utility of individual articles. These skills are known as critical appraisal skills, and they require some knowledge of biostatistics, clinical epidemiology, decision analysis and economics, and clinical knowledge. Evidence Based Reviews in Surgery (EBRS) is a program jointly sponsored by the Canadian Association of General Surgeons (CAGS) and the American College of Surgeons (ACS). The primary objective of EBRS is to help practising surgeons improve their critical appraisal skills. During the academic year, 8 clinical articles are chosen for review and discussion. They are selected for their clinical relevance to general surgeons and because they cover a spectrum of issues im -port ant to surgeons, including causation or risk factors for disease, natural history or prognosis of disease, how to quantify disease, diagnostic tests, early diagnosis and the effectiveness of treatment. A methodological article guides the reader in critical appraisal of the clinical article. Methodological and clinical reviews of the article are performed by experts in the relevant areas and posted on the EBRS website, where they are archived indefinitely. In addition, a listserv allows participants to discuss the monthly article. Surgeons who participate in the monthly packages can obtain Royal College of Physicians and Surgeons of Canada Maintenance of Certification credits and/or continuing medical education credits for the current article only by reading the monthly articles, participating in the listserv discussion, reading the methodological and clinical reviews and completing the monthly online evaluation and multiple choice questions. We hope readers will find EBRS useful in improving their critical appraisal skills and in keeping abreast of new developments in general surgery. Four reviews are published in condensed versions in the Canadian Journal of Surgery, 4 are published in the Journal of the American College of Surgeons and 4 are published in Diseases of the Colon and Rectum. For further information about EBRS, please refer to the CAGS or ACS websites. Questions and comments can be directed to the program administrator, Marg McKenzie, at mmckenzie@mtsinai.on.ca.

Objective: To determine if screening mammography produced the expected increase in the incidence of early-stage breast cancer and reduced the expected incidence of late-stage breast cancer in women 40 years of age or older. Design: Population-based observation study using a before and after cohort time series design. Data Sources: 1) National Health Interview Survey; 2) Surveillance, Epidemiology and End Results (SEER) data; 3) United States Census. Results: The introduction of screening mammography in the United States has been associated with a doubling in the number of cases of early-stage breast cancer detected each year from 112 to 234 cases per 100 000 women — an absolute increase of 122 cases per 100 000 women. Concomitantly, the rate at which women present with late-stage cancer has decreased from 102 to 94 cases per 100 000 women — an absolute decrease of 8 cases per 100 000 women. With the assumption of a constant underlying disease burden, it was estimated that only 8 of the 122 additional early-stage cancers diagnosed would progress to advanced disease. After excluding the transient excess incidence associated with hormone replacement therapy and adjusting for trends in the incidence of breast cancer among women younger than 40 years old, it was estimated that breast cancer was overdiagnosed (i.e., tumours were detected on screening that would never have led to clinical symptoms) in 70 000 women in 2008 and 1.3 million women in the past 30 years. Conclusion: Despite substantial increases in the number of early-stage breast cancer detected, screening mammography has only marginally reduced the rate at which women present with late-stage cancer.

BACKGROUND Recent data suggest that massively transfused patients have lower mortality rates when high ratios (>1:2) of plasma or platelets to red blood cells (RBCs) are used. Blunt and penetrating trauma patients have different injury patterns and may respond differently to resuscitation. This study was performed to determine whether mortality after high product ratio massive transfusion is different in blunt and penetrating trauma patients. METHODS Patients receiving 10 or more units of RBCs in the first 24 hours after admission to one of 23 Level I trauma centers were analyzed. Baseline physiologic and biochemical data were obtained. Univariate and logistic regression analyses were performed. Adjusted mortality in patients receiving high (≥ 1:2) and low (

Current trauma resuscitation guidelines recommend giving an initial crystalloid bolus as first line for resuscitation. Recent studies have shown a survival benefit for trauma patients resuscitated with high ratios of fresh frozen plasma (FFP) to packed red blood cells (PRBC). Our aim was to determine whether the volume of crystalloid given during resuscitation correlated with differences in morbidity or mortality based on the ratio of FFP:PRBC given.This was a retrospective review of 2,473 transfused trauma patients at 23 Level I trauma centers from July 2005 to October 2007. Patients were separated based on the ratios of FFP:PRBC they received (1:4, 1:4-1:1, and1:1) and then analyzed for morbidity and mortality based on whether or not they received at least 1 L crystalloid for each unit of PRBC. Outcomes analyzed were 6-hour, 24-hour, and 30-day survival as well as intensive care unit (ICU)-free days, ventilator-free days, and hospital-free days.Massive transfusion patients who received1:4 ratios of FFP:PRBC had significantly improved 6-hour, 24-hour, and 30-day mortality and significantly more ventilator-free days if they received at least 1 L of crystalloid for each unit of PRBC. Nonmassive transfusion patients who received1:4 ratios of FFP:PRBC had significantly improved 6-hour, 24-hour, and 30-day mortality and significantly more ICU-free days, ventilator-free days, and hospital-free days if they received at least 1 L crystalloid for each unit of PRBC. In both massive and nonmassive transfusion groups, the survival benefit and morbidity benefit was progressively less for the 1:4 to 1:1 FFP:PRBC groups and1:1 FFP:PRBC groups.If high ratios of FFP:PRBC are unable to be given to trauma patients, resuscitation with at least 1 L of crystalloid per unit of PRBC is associated with improved overall mortality.

Background Improvements in trauma systems and resuscitation have increased survival in severely injured patients. Massive transfusion has been increasingly used in the civilian setting. Objective predictors of mortality have not been well described. This study examined data available in the early postinjury period to identify variables that are predictive of 24-hour- and 30-day mortality in massively transfused trauma patients. Methods Massively transfused trauma patients from 23 Level I centers were studied. Variables available on patient arrival that were predictive of mortality at 24 hours were entered into a logistic regression model. A second model was created adding data available 6 hours after injury. A third model evaluated mortality at 30 days. Receiver operating characteristic curves and the Hosmer-Lemeshow test were used to assess model quality. Results Seven hundred four massively transfused patients were analyzed. The model best able to predict 24-hour mortality included pH, Glasgow Coma Scale score, and heart rate, with an area under the receiver operating characteristic curve (AUROC) of 0.747. Addition of the 6-hour red blood cell requirement increased the AUROC to 0.769. The model best able to predict 30-day mortality included the above variables plus age and Injury Severity Score with an AUROC of 0.828. Conclusion Glasgow Coma Scale score, pH, heart rate, age, Injury Severity Score, and 6-hour red blood cell transfusion requirement independently predict mortality in massively transfused trauma patients. Models incorporating these data have only a modest ability to predict mortality and should not be used to justify withholding massive transfusion in individual cases.

Management of penetrating colon injuries in the presence of multiple associated risk factors is controversial. Issues not considered in previous management strategies are patient perception of quality of life with a colostomy and the true cost of each therapeutic option, which includes colostomy supplies and costs of colostomy takedown. To evaluate these issues, we performed a cost-utility analysis.We constructed a decision tree with 3 options: primary repair, resection and anastomosis, and colostomy. Chance and decision nodes on each decision branch represent injury severity, complications, colostomy takedown, and death. Chance node frequencies and utility assignments were taken from published data. We obtained actual costs for all components of perioperative care. The outcomes reported are cost and quality of life.Colostomy has the least quality of life and the greatest cost. Primary repair and resection each dominate colostomy in the baseline analysis. No variable significantly altered these conclusions in sensitivity analyses.Simple suture or resection and anastomosis at the time of initial exploration is the dominant management method for penetrating colon trauma. It also demonstrates the trade-off between cost and life expectancy of the 3 management options.

The influence of patient preference and treatment costs has not been considered in previous analyses of wound management decisions for contaminated right lower quadrant incisions.We performed a decision and cost-utility analysis, conducting a MEDLINE search of the postappendectomy wound infection literature to establish assumptions and assign baseline probability estimates. Institution-specific cost data were obtained, and utility assignments were made by the authors. Studies used to assign baseline probabilities fulfilled the following criteria: perforated appendix or gangrenous appendicitis, use of perioperative antibiotics active against aerobic and anaerobic bacteria, and data stratified by wound management, operative findings, and infection rate.We constructed a decision tree comparing three methods of wound management for contaminated right lower quadrant incisions: primary closure, delayed primary closure, and secondary closure. Utility (a quality of life measure) was assigned to ultimate health states to incorporate patient preference. We calculated the cost-utility for each method of wound management and found that primary closure was of optimum cost-utility compared with delayed primary closure and secondary closure. To gain one quality-adjusted life year treating a population of patients with contaminated incisions, primary closure saves $22,635 over delayed primary closure and another $22,340 over secondary closure. This decision, tested by two-way sensitivity analyses, was sensitive only to high primary closure infection rates.Challenging traditional surgical dogma, cost-utility analysis shows that primary closure is the favored method of management for contaminated right lower quadrant incisions. This analysis is specific to right lower quadrant incisions and the conclusion is valid for all estimated primary infection rates less than 0.27.