Classification of comorbidity in trauma: the reliability of pre-injury ASA physical status classification.

BACKGROUND: Pre-injury comorbidities can influence the outcomes of severely injured patients. Pre-injury comorbidity status, graded according to the American Society of Anesthesiologists Physical Status (ASA-PS) classification system, is an independent predictor of survival in trauma patients and is recommended as a comorbidity score in the Utstein Trauma Template for Uniform Reporting of Data. Little is known about the reliability of pre-injury ASA-PS scores. The objective of this study was to examine whether the pre-injury ASA-PS system was a reliable scale for grading comorbidity in trauma patients. METHODS: Nineteen Norwegian trauma registry coders were invited to participate in a reliability study in which 50 real but anonymised patient medical records were distributed. Reliability was analysed using quadratic weighted kappa (κ(w)) analysis with 95% CI as the primary outcome measure and unweighted kappa (κ) analysis, which included unknown values, as a secondary outcome measure. RESULTS: Fifteen of the invitees responded to the invitation, and ten participated. We found moderate (κ(w)=0.77 [95% CI: 0.64-0.87]) to substantial (κ(w)=0.95 [95% CI: 0.89-0.99]) rater-against-reference standard reliability using κ(w) and fair (κ=0.46 [95% CI: 0.29-0.64]) to substantial (κ=0.83 [95% CI: 0.68-0.94]) reliability using κ. The inter-rater reliability ranged from moderate (κ(w)=0.66 [95% CI: 0.45-0.81]) to substantial (κ(w)=0.96 [95% CI: 0.88-1.00]) for κ(w) and from slight (κ=0.36 [95% CI: 0.21-0.54]) to moderate (κ=0.75 [95% CI: 0.62-0.89]) for κ. CONCLUSIONS: The rater-against-reference standard reliability varied from moderate to substantial for the primary outcome measure and from fair to substantial for the secondary outcome measure. The study findings indicate that the pre-injury ASA-PS scale is a reliable score for classifying comorbidity in trauma patients.

Collecting core data in severely injured patients using a consensus trauma template: an international multicentre study.

INTRODUCTION: No worldwide, standardised definitions exist for documenting, reporting and comparing data from severely injured trauma patients. This study evaluated the feasibility of collecting the data variables of the international consensus-derived Utstein Trauma Template. METHODS: Trauma centres from three different continents were invited to submit Utstein Trauma Template core data during a defined period, for up to 50 consecutive trauma patients. Directly admitted patients with a New Injury Severity Score (NISS) equal to or above 16 were included. Main outcome variables were data completeness, data differences and data collection difficulty. RESULTS: Centres from Europe (n = 20), North America (n = 3) and Australia (n = 1) submitted data on 965 patients, of whom 783 were included. Median age was 41 years (interquartile range (IQR) 24 to 60), and 73.1% were male. Median NISS was 27 (IQR 20 to 38), and blunt trauma predominated (91.1%). Of the 36 Utstein variables, 13 (36%) were collected by all participating centres. Eleven (46%) centres applied definitions of the survival outcome variable that were different from those of the template. Seventeen (71%) centres used the recommended version of the Abbreviated Injury Scale (AIS). Three variables (age, gender and AIS) were documented in all patients. Completeness > 80% was achieved for 28 variables, and 20 variables were > 90% complete. CONCLUSIONS: The Utstein Template was feasible across international trauma centres for the majority of its data variables, with the exception of certain physiological and time variables. Major differences were found in the definition of survival and in AIS coding. The current results give a clear indication of the attainability of information and may serve as a stepping-stone towards creation of a European trauma registry.

The flip test: a reappraisal.

STUDY DESIGN: Diagnostic study. OBJECTIVE: To assess the construct validity of the flip test as a sign of nerve root tension. SUMMARY OF BACKGROUND DATA: The flip test is commonly performed in patients with sciatica to confirm or otherwise nerve root tension evidenced by a restricted supine straight leg raise (SLR). Passive extension of the knee with the patient in the erect position and the hip flexed is reported to cause a sudden falling or flipping back of the trunk. Although widely known there are no research articles validating this test. METHODS: Sixty-seven patients with sciatica and magnetic resonance imaging scans confirming disc protrusion and nerve root compression underwent the flip test. The response of the patient was recorded, compared with the supine SLR, and subjected to statistical analysis. RESULTS: Thirty-three percent of patients felt no pain, 39% felt pain on full extension of the knee, and 28% resisted full extension of the knee due to pain. Only one-third of patients demonstrated a "flip." The response was related to the supine SLR, such that patients with high SLRs tended not to show a painful reaction whereas all patients with a supine SLR below 45 degrees showed a painful response. CONCLUSION: We consider that the flip test has been substantially misinterpreted in the past. However, it remains a useful check of nerve root tension but only for patients with supine SLRs below 45 degrees . The most reliable response was not a flip but the demonstration of pain on extension of the knee. We would recommend the term "sitting SLR test," as a more accurate and less misleading name.

Different definitions of patient outcome: consequences for performance analysis in trauma.

BACKGROUND: Death during acute care hospitalisation is commonly used as a principal outcome indicator in injury research. This endpoint excludes post-hospital trauma-related deaths, which are substantial according to recent US studies. Two additional ways of defining outcome in trauma victims are also used; by end of somatic care, and at 30 days after injury. Our primary aim was to analyse how the different definitions of trauma outcome influence performance analyses. Secondly, we wanted to evaluate whether 30 days mortality after injury, which is widely used in other parts of biomedicine and recommended by the United Nations for use in transport statistics, is a suitable endpoint in trauma research. MATERIALS AND METHODS: We conducted a retrospective analysis of prospectively collected data from the hospital based trauma registry at Ulleval University Hospital (UUH) in Oslo, Norway. Outcome measure was mortality at discharge from UUH, i.e., by "end of acute care", at end of somatic care defined as discharge from final acute care hospital, and at 30 days after injury. Analyses were performed according to conventional TRISS methodology. RESULTS: 3332 of 3446 patients from the years 2000-2004 were included. Of these, 323 (9.7%) died within 30 days of injury or during somatic care more than 30 days after injury. Mortality varied with outcome definition, with 264 deaths (81.7% of total deaths) before discharge from UUH, 318 (98.4%) before end of somatic care, and 308 (95.4%) within 30 days after injury. TRISS-based trauma system performance evaluation for blunt trauma showed significantly better outcome than predicted with discharge from UUH as outcome definition, whereas for category 30 days after injury, performance was clearly less favourable. Performance for penetrating trauma was not affected, since all deaths occurred before 30 days, and nearly all before discharge from UUH. CONCLUSIONS: A substantial number of in-hospital deaths following blunt trauma occurs after discharge from the primary institution, i.e., unnoticed when "end of acute care" is used as outcome definition. Consequently, outcome definition influenced performance when comparing our institution to an acknowledged standard. We recommend mortality occurring within 30 days of injury as endpoint in trauma research.

Pre-injury ASA physical status classification is an independent predictor of mortality after trauma.

BACKGROUND: The ability of an organism to withstand trauma is determined by the injury per se and inherent properties of the organism at the time of injury. We analyzed whether pre-injury morbidity scored on a four-level ordinal scale according to the American Society of Anesthesiologists Physical Status (ASA-PS) classification system predicts mortality after trauma. MATERIALS: From a total of 3,773 prospectively collected patients (years 2000-2004), 3,728 patients were included. Main outcome measure was mortality 30 days after injury. The effect of pre-injury ASA-PS on mortality was assessed using linear logistic regression analysis, controlling for Revised Trauma Score (RTS), Injury Severity Score (ISS), and age. RESULTS: Mortality increased with increasing pre-injury ASA-PS, age, and ISS, and with decreasing RTS. Unadjusted mortality rates were 5.7% in ASA-PS 1, 12.3% in ASA-PS 2, and 26.4% in ASA-PS 3-4. This increasing mortality trend across pre-injury ASA-PS group was evident in nearly all categories of ISS, RTS, and age. Odds ratio for death was 1.76 (95% CI, 1.14-2.72) for pre-injury ASA-PS 2, and 2.25 (95% CI, 1.36-3.71) for ASA-PS 3-4 compared with for ASA-PS 1 and adjusted for ISS, RTS, and age. There were no interaction effects between pre-injury ASA-PS and the other variables. CONCLUSIONS: Pre-injury ASA-PS score was an independent predictor of mortality after trauma, also after adjusting for the major variables in the traditional TRISS (Trauma and Injury Severity Score) formula. Including pre-injury ASA-PS score might improve the predictive power of a survival prediction model without complicating it.

Scoring of anatomic injury after trauma: AIS 98 versus AIS 90--do the changes affect overall severity assessment?

BACKGROUND: Although several changes were implemented in the 1998 update of the abbreviated injury scale (AIS 98) versus the previous AIS 90, both are still used worldwide for coding of anatomic injury in trauma. This could possibly invalidate comparisons between systems using different AIS versions. Our aim was to evaluate whether the use of different coding dictionaries affected estimation of Injury Severity Score (ISS), New Injury Severity Score (NISS) and probability of survival (Ps) according to TRISS in a hospital-based trauma registry. MATERIALS AND METHODS: In a prospective study including 1654 patients from Ulleval University Hospital, a Norwegian trauma referral centre, patients were coded according to both AIS 98 and AIS 90. Agreement between the classifications of ISS, NISS and Ps according to TRISS methodology was estimated using intraclass correlation coefficients (ICC) with 95% CI. RESULTS: ISS changed for 378 of 1654 patients analysed (22.9%). One hundred and forty seven (8.9%) were coded differently due to different injury descriptions and 369 patients (22.3%) had a change in ISS value in one or more regions due to the different scoring algorithm for skin injuries introduced in AIS 98. This gave a minimal change in mean ISS (14.74 versus 14.54). An ICC value of 0.997 (95% CI 0.9968-0.9974) for ISS indicates excellent agreement between the scoring systems. There were no significant changes in NISS and Ps. CONCLUSIONS: There was excellent agreement for the overall population between ISS, NISS and Ps values obtained using AIS 90 and AIS 98 for injury coding. Injury descriptions for hypothermia were re-introduced in the recently published AIS 2005. We support this change as coding differences due to hypothermia were encountered in 4.3% of patients in the present study.

Validity of nutritional screening and assessment tools.

OBJECTIVE: The aim of this paper is to address the design and analysis of validity studies for evaluating the performance of a nutritional screening or assessment tool. METHODS: Statistical aspects of validity are discussed with the non-statistician in mind. Particular emphasis is placed on construct and criterion validity. Design issues are considered in relation to numbers of subjects and assessments. Appropriate methods of analysis are considered, as is interpretation of results. Practical suggestions regarding the implementation of validity studies in the field of nutrition risk assessment are proposed. CONCLUSION: Guidelines for the standardization of the design, analysis, and publication of results are presented.

Reliability of nutritional screening and assessment tools.

OBJECTIVE: The aim of this paper is to address the design and analysis of studies for evaluating the reliability of a nutritional screening or assessment tool. METHODS: Statistical aspects of reliability are discussed with the non-statistician in mind. Design issues are considered in relation to numbers of raters and subjects and to the appropriateness of raters. The analysis of data to obtain a measure of reliability and its confidence interval is illustrated with examples. Practical suggestions regarding the implementation of reliability studies in the field of nutritional risk assessment are proposed. CONCLUSION: Guidelines for the standardization of the design, analysis, and publication of results are presented.

Development of a nutritional screening or assessment tool using a multivariate technique.

OBJECTIVE: The aims of this paper are to consider the important design stages required to develop a nutritional screening or assessment tool and to present an analysis for identifying important risk factors associated with malnutrition. METHODS: Design issues, such as sample selection and sample size, are addressed in relation to the study protocol. The various steps involved in tool development are outlined. Appropriate univariate and multivariate techniques are discussed with the non-statistician in mind. Emphasis is placed on the linear logistic regression method. Practical suggestions relating to the development of a tool for nutritional risk assessment are proposed, and methodology is illustrated with data from a published study. CONCLUSION: Guidelines for the standardization of the design, analyses, and publication of results are presented.

The methodology of nutritional screening and assessment tools.

BACKGROUND: The aim of this paper was to give a critical appraisal of the methodology of nutritional screening and assessment tools. METHODS: A literature search identified 44 tools. Each tool was assessed in relation to details of its application, method of derivation and evaluation of its performance. RESULTS: The findings indicate that tools were published with insufficient details regarding their intended use and method of derivation, and with an inadequate assessment of their effectiveness. An appraisal of these features judged that no one tool satisfied a set of criteria regarding scientific merit. CONCLUSION: There is thus a need to ensure that nutritional screening and assessment tools are developed using procedures based on good design and sound statistical practice. This paper suggests that a unified approach using multivariate techniques could make a significant contribution to this process.