Bryan G. Garber

Adult respiratory distress syndrome : A systematic overview of incidence and risk factors

OBJECTIVE To determine the published incidence of adult respiratory distress syndrome (ARDS) as well as the clinical evidence supporting a casual association between ARDS and its major risk factors. DATA SOURCES The National Library of Medicine MEDLINE database and the bibliographies of selected articles. STUDY SELECTION Clinical studies were selected from the English literature, if they pertained to either the incidence of ARDS or its association with one or more commonly identified risk factors. DATA EXTRACTION All relevant studies identified by the search were evaluated for strength of design, and risk factors were scored according to established criteria for the strength of causation. DATA SYNTHESIS A total of 83 articles were considered relevant: six of incidence and 77 on risk factors. Only 49% of the 83 articles provided a definition of ARDS; a definition of risk factors was given in 64%, and 23% had no definition for either ARDS or risk factors. The published, population-based incidence of ARDS ranges from 1.5 to 5.3/10(5) population/yr. The strongest clinical evidence supporting a cause-effect relationship was identified for sepsis, aspiration, trauma, and multiple transfusions. The weakest clinical evidence was identified for disseminated intravascular coagulation. The following study types were represented by the 77 articles on risk factors: observational case-series (56%); cohorts (23%); case-controls (12%); nonrandomized clinical trials (5%); and randomized clinical trials (3%). Only a single study reported an odds ratio. CONCLUSIONS The significant variation in the incidence of ARDS is attributed to differences in the type and strength of study designs, as well as definitions or ARDS. While a substantial body of evidence exists concerning a casual role of ARDS risk factors, such as sepsis, aspiration, and trauma, > 60% of clinical studies employed weak designs. The lack of reproducible definitions for ARDS or its potential risk factors in 49% of studies raises concerns about the validity of the conclusions of these studies regarding the association between ARDS and the supposed risk factors.

Validation of trauma and injury severity score in blunt trauma patients by using a Canadian trauma registry.

OBJECTIVE To compare outcomes in blunt trauma by using Trauma and Injury Severity Score (TRISS) models derived from the Major Trauma Outcome Study (MTOS) and the Ontario Trauma Registry (OTR) as well as to evaluate the role of the Revised Trauma Score within the TRISS model. METHODS Consecutive blunt trauma cases from 11 Level I trauma centers over a 4-year period were identified from the OTR. Coefficients of the Revised Trauma Score were modified using the Ontario data and this score was tested by using the Hosmer-Lemeshow Goodness of Fit Test. Two Ontario-specific TRISS models were developed with revised coefficients. The first used the standard Revised Trauma Score and the second used the Revised Trauma Score with regenerated coefficients. The accuracy of mortality predictions for all models were compared by using a Hosmer-Lemeshow Goodness of Fit procedure. Additionally, each TRISS models performance characteristics and receiver operating characteristic (ROC) curves were used to evaluate their discriminative capabilities. RESULTS A total of 5,436 cases were incorporated in the analysis. Patients with all component TRISS variables had a significantly lower mortality compared to all blunt trauma patients (7.0% vs. 15.5%,p < 0.01). Use of the Revised Trauma Score led to the exclusion of 40% of cases because of absent data necessary to compute the score. The Hosmer-Lemeshow Goodness of Fit statistic for the Revised Trauma Score was 79.45 (p = 0.0001). The Hosmer-Lemeshow Goodness of Fit Statistic ranged from 11.42, p = 0.175 and 13.1, p = 0.125 for the Ontario TRISS models compared to 25.62, p < 0.005 for the MTOS TRISS model. Sensitivity of all three TRISS models ranged from 98% to 99% with specificity ranging from 24% to 35%. ROC curves were identical for all three TRISS models. CONCLUSIONS TRISS demonstrated satisfactory performance in a Canadian blunt trauma population. Although revision of coefficients led to a better fit on the Hosmer-Lemeshow statistic, ROC curves demonstrated virtually identical performance of the MTOS and Ontario-based TRISS models. The poor performance of the Revised Trauma Score and the observation that its use led to the exclusion of 40% of cases with a higher mortality raises concerns regarding its use in the TRISS model.

Differential performance of TRISS-like in early and late blunt trauma deaths

OBJECTIVES (1) To independently validate the Trauma and Injury Severity Score-Like (TRISS-Like) model derived by Offner et al. (Revision of TRISS for intubated patients. J Trauma. 1992;32:32-35) in a population of Canadian blunt trauma victims, and (2) to compare the ability of this model to predict mortality in early and late trauma deaths. STUDY POPULATION Prospective cohort of blunt trauma cases with Injury Severity Score > 12 identified from the Ontario Trauma Registry over a 5-year period. STUDY DESIGN The TRISS-Like model consisting of age, Injury Severity Score, systolic blood pressure, and best motor response of the Glasgow Coma Scale was evaluated as to its ability to predict mortality by determining the sensitivity, specificity, and the area under the receiver operating characteristic curve. The sample was then divided into early (< or = 7 days) and late mortality subgroups in which model performance was evaluated with respect to time of death. RESULTS A total of 7,703 patients were included in this analysis. The overall mortality was 12.3%. The TRISS-Like model allowed for assessment of an additional 23% of patients than would standard TRISS and performed with a sensitivity of 97.1%, specificity of 39.8% and an area under the receiver operating characteristic curve of 0.873. Analysis of mortality with respect to time demonstrated that 75% of deaths occurred by day 7. The specificity and receiver operating characteristic area increased in the early (< or = 7 days) subgroup, 46.5% and 0.935, respectively, compared with 20.8% and 0.778 in the late mortality group. CONCLUSIONS TRISS-Like demonstrated similar performance to that reported with the standard TRISS model but with the additional advantage that it is more generalizable because it can be applied to intubated patients. TRISS-Like demonstrated substantially superior performance in early trauma deaths compared with those that occurred late. This differential performance may be because the model does not include risk factors for late mortality.

An economic evaluation of trauma care in a Canadian lead trauma hospital

BACKGROUND The objective was to determine the average cost per quality-adjusted life year (QALY) gained of treating trauma victims at a tertiary trauma hospital and to determine the cost-effectiveness of trauma care at this center. The setting was a tertiary trauma center in the province of Ontario, Canada. The study population consisted of consecutive trauma admissions with ISS > 12 from April, 1994 to April, 1996. The study was of a retrospective cohort design with a cross-sectional survey. METHODS The hospital perspective was taken. Costs were determined from a retrospective cohort using a hospital-based case-costing system. Utility estimates for calculation of QALYs gained were obtained using a cross-sectional survey design. Cost-effectiveness was determined by estimating the incremental cost/QALY attributable to treatment at the trauma center. Sensitivity analysis was employed to vary assumptions about the proportion of costs and increased survival. RESULTS 484 patients with a median age of 39 years and a median ISS of 22 were studied. The average cost per QALY was

Use of abdominal computed tomography in blunt trauma: do we scan too much?

1,721, with a maximum value of

MANAGEMENT OF ADULT SPLENIC INJURIES IN ONTARIO: A POPULATION-BASED STUDY

3,861. The increase in cost per QALY gained for treatment in a tertiary care center as opposed to a nontrauma center was

Management of splenic injuries in a Canadian trauma centre.

4,303, assuming a 20% increase in survival and assuming that the existence of the center increased the cost of care by 50%. The incremental cost/QALY ranged from

Acute Respiratory Distress Syndrome: The Epidemiology of ARDS

191 to

HOW WELL DO WE SELECT PATIENTS FOR ABDOMINAL COMPUTED TOMOGRAPHY FOLLOWING BLUNT TRAUMA

15,492 in the sensitivity analysis varying assumptions about the increased proportion of costs and survival attributable to care at the tertiary trauma center. CONCLUSIONS This is the first economic evaluation of tertiary trauma care which includes both costs as opposed to charges as well as estimates of the QALYs gained. The results suggest that tertiary trauma care is cost-effective and less costly than treatment programs for other disease conditions when the quality-adjusted life years gained are included in the evaluation.