Is there a 'weekend effect' in major trauma?

BACKGROUND: Many previous studies have shown that patients admitted to hospital at weekends have worse outcomes than those on other days. It has been proposed that parity of clinical services throughout the week could mitigate the 'weekend effect'. This study aimed to determine whether or not a weekend effect is observed within an all-hours consultant-led major trauma service. METHODS: We undertook an observational cohort study using data submitted by all 22 major trauma centres (MTCs) in England to the Trauma Audit & Research Network. The inclusion criteria were all major trauma patients admitted for at least 3 days, admitted to a high-dependency area, or deceased following arrival at hospital. Patients with Injury Severity Score (ISS) >15 were also analysed separately. The outcome measures were length of stay, in-hospital mortality and Glasgow Outcome Score (GOS). Secondary transfer of patients between hospitals was also included as a process outcome. RESULTS: There were 49 070 patients, 22 248 (45.3%) of which had an ISS >15. Within multivariable logistic regression models, odds of secondary transfer into an MTC were higher at night (adjusted OR 2.05, 95% CI 1.93 to 2.19) but not during the day at weekends (1.09, 0.99 to 1.19). Neither admission at night nor at the weekend was associated with increased length of stay, worse GOS or higher odds of in-hospital death. These findings remained stable when confining analyses to the most severely injured patients (ISS >15), excluding transferred patients, and using a single mid-week (Wednesday) baseline. CONCLUSIONS: After adjustment for known confounders the weekend effect is not detectable within a regionalised major trauma service.

Quantifying the healthcare costs of treating severely bleeding major trauma patients: a national study for England.

INTRODUCTION: Severely bleeding trauma patients are a small proportion of the major trauma population but account for 40% of all trauma deaths. Healthcare resource use and costs are likely to be substantial but have not been fully quantified. Knowledge of costs is essential for developing targeted cost reduction strategies, informing health policy, and ensuring the cost-effectiveness of interventions. METHODS: In collaboration with the Trauma Audit Research Network (TARN) detailed patient-level data on in-hospital resource use, extended care at hospital discharge, and readmissions up to 12 months post-injury were collected on 441 consecutive adult major trauma patients with severe bleeding presenting at 22 hospitals (21 in England and one in Wales). Resource use data were costed using national unit costs and mean costs estimated for the cohort and for clinically relevant subgroups. Using nationally available data on trauma presentations in England, patient-level cost estimates were up-scaled to a national level. RESULTS: The mean (95% confidence interval) total cost of initial hospital inpatient care was £19,770 (£18,177 to £21,364) per patient, of which 62% was attributable to ventilation, intensive care, and ward stays, 16% to surgery, and 12% to blood component transfusion. Nursing home and rehabilitation unit care and re-admissions to hospital increased the cost to £20,591 (£18,924 to £22,257). Costs were significantly higher for more severely injured trauma patients (Injury Severity Score ≥15) and those with blunt injuries. Cost estimates for England were £148,300,000, with over a third of this cost attributable to patients aged 65 years and over. CONCLUSIONS: Severely bleeding major trauma patients are a high cost subgroup of all major trauma patients, and the cost burden is projected to rise further as a consequence of an aging population and as evidence continues to emerge on the benefits of early and simultaneous administration of blood products in pre-specified ratios. The findings from this study provide a previously unreported baseline from which the potential impact of changes to service provision and/or treatment practice can begin to be evaluated. Further studies are still required to determine the full costs of post-discharge care requirements, which are also likely to be substantial.

Prediction modelling for trauma using comorbidity and 'true' 30-day outcome.

BACKGROUND: Prediction models for trauma outcome routinely control for age but there is uncertainty about the need to control for comorbidity and whether the two interact. This paper describes recent revisions to the Trauma Audit and Research Network (TARN) risk adjustment model designed to take account of age and comorbidities. In addition linkage between TARN and the Office of National Statistics (ONS) database allows patient's outcome to be accurately identified up to 30 days after injury. Outcome at discharge within 30 days was previously used. METHODS: Prospectively collected data between 2010 and 2013 from the TARN database were analysed. The data for modelling consisted of 129 786 hospital trauma admissions. Three models were compared using the area under the receiver operating curve (AuROC) for assessing the ability of the models to predict outcome, the Akaike information criteria to measure the quality between models and test for goodness-of-fit and calibration. Model 1 is the current TARN model, Model 2 is Model 1 augmented by a modified Charlson comorbidity index and Model 3 is Model 2 with ONS data on 30 day outcome. RESULTS: The values of the AuROC curve for Model 1 were 0.896 (95% CI 0.893 to 0.899), for Model 2 were 0.904 (0.900 to 0.907) and for Model 3 0.897 (0.896 to 0.902). No significant interaction was found between age and comorbidity in Model 2 or in Model 3. CONCLUSIONS: The new model includes comorbidity and this has improved outcome prediction. There was no interaction between age and comorbidity, suggesting that both independently increase vulnerability to mortality after injury.

Do prolonged primary transport times for traumatic brain injury patients result in deteriorating physiology? A cohort study.

BACKGROUND: Recent interest has focused on reorganizing emergency medical services (EMS) for traumatic brain injury (TBI) patients, with bypass of nonspecialist hospitals and direct transportation to distant neuroscience centers. Although this could expedite neurosurgery and neurocritical care, deteriorating physiology could be deleterious. METHODS: We performed a multicenter cohort study examining adult patients with significant TBI enrolled in the English National Trauma Registry. The distributions and correlation of first recorded prehospital and emergency department (ED) vital signs were compared, and the effect of time on changes in vital signs was examined in bivariate and multivariate analyses. RESULTS: A total of 7149 eligible patients were studied. No clinically significant differences were apparent between distributions of prehospital and ED vital signs. Moderate linear correlation was observed for field and ED pulse rate (r(2) = 0.34) and GCS values (Spearman's rho = 0.76), with weak correlation apparent for systolic blood pressure (r(2) = 0.28) and respiratory rate (r(2) = 0.28). Eight percent of cases' vital signs deteriorated in the prehospital interval; however, odds of deterioration in vital sign status did not vary significantly with duration of EMS interval. CONCLUSION: The similarity between prehospital and ED vital signs, and lack of association between EMS interval and physiological deterioration, may support a strategy of direct transportation of TBI cases to specialist centers. Further research is necessary to identify patients at risk from deterioration during bypass and to investigate effects on mortality.

The accuracy of alternative triage rules for identification of significant traumatic brain injury: a diagnostic cohort study.

INTRODUCTION: Traumatic brain injury (TBI) is a leading cause of death and disability in young adults. Reorganisation of trauma services with direct triage of suspected head injury patients to trauma centres may improve outcomes following TBI. This study aimed to determine the sensitivity of principal English triage tools for identifying significant TBI. METHODS: We performed a diagnostic cohort study using data prospectively collated from the Trauma Audit and Research Network database between 2005 and 2011. Adult head injury patients were retrospectively classified according to London Ambulance Service (LAS) and Head Injury Transportation Straight to Neurosurgery study (HITS-NS) triage criteria. Sensitivity and specificity were then calculated against a reference standard of significant TBI, comprising head region abbreviated injury score (AIS) ≥3 or neurosurgical operation. RESULTS: 6559 patients were included in complete case analyses. The LAS and HITS-NS triage tools demonstrated sensitivities of 44.5% (95% CI 43.2 to 45.9) and 32.6% (95% CI 31.4 to 33.9), respectively, for identifying significant TBI patients. False negative significant TBI cases were relatively older, more likely to be female, more frequently secondary to low-level falls, and were less likely to have very severe AIS five or six head injuries, p<0.01. CONCLUSIONS: A considerable proportion of significant head injury patients may not be triaged directly to trauma centres. Investment is therefore necessary to improve the accuracy of existing triage rules and maintain expertise in TBI diagnosis and management in non-specialist emergency departments.

Recent massive blood transfusion practice in England and Wales: view from a trauma registry.

BACKGROUND: Few studies have characterised massive blood transfusion (MBT) practice in UK trauma. This study describes the Trauma Audit and Research Network experience of MBT over a 4-year period, and examines variables predictive of MBT and mortality following MBT. METHODS: Prospectively collected data between 2005 and 2009 from the Trauma Audit and Research Network database were analysed. MBT incidence was examined, and patient characteristics, blood component usage and mortality compared to non-MBT patients. Clinical and injury features predictive of massive transfusion, and risk factors predictive of death in MBT, were analysed using multivariate logistic regression. RESULTS: 157 patients (0.4%) received MBT, with a mortality rate of 40.3%. MBT patients were younger, more likely to be male and to have sustained more severe trauma (median age 39.2 years, median Injury Severity Score 27, 78% male, p<0.01). No patients received platelets and fresh frozen plasma (FFP) in 1:1 ratios with packed red cells. Multivariate analysis showed: age, admission pulse rate, systolic blood pressure, and injury type; thoracic, abdominal, pelvis, were significant predictors of MBT. Injury Severity Score and admission pulse rate were also independent predictors of death in MBT, but level of platelet and FFP use were not found to be statistically significant. CONCLUSION: MBT is a rare event with high mortality in UK trauma. Haemostatic resuscitation is not currently practiced in the UK and the authors were unable to show that FFP and platelet use were significant predictors of survival in MBT.

The effect of an organized trauma system on mortality in major trauma involving serious head injury: a comparison of the United kingdom and victoria, australia.

OBJECTIVE: To compare outcomes following major trauma involving serious head injury managed in an inclusive trauma system (Victoria, Australia) and a setting where rationalization of trauma services is absent (England/Wales). BACKGROUND: The introduction of regionalized trauma systems has the potential to reduce preventable deaths, but their uptake has been slow around the world. Improved understanding of the benefits and limitations of different systems of trauma care requires comparison across systems. METHODS: Mortality outcomes following major trauma involving serious head injury managed in the 2 settings were compared using multivariate logistic regression. Data pertaining to the period July 2001 to June 2006 (inclusive) were extracted from the Trauma Audit and Research Network (TARN) in the United Kingdom and the Victorian State Trauma Registry (VSTR) in Australia. RESULTS: A total of 4064 (VSTR) and 6024 (TARN) cases were provided for analysis. The odds of death for TARN cases were significantly higher than those for VSTR cases [odds ratio = 2.15, 95% confidence interval = 1.95-2.37]. After adjusting for age, gender, cause of injury, head injury severity, Glasgow Coma Scale score, and Injury Severity Score, TARN cases remained at elevated odds of death (3.22; 95% confidence interval = 2.84-3.65) compared with VSTR cases. CONCLUSIONS: Management of the severely injured patient with an associated head injury in England and Wales, where an organized trauma system is absent, was associated with increased risk-adjusted mortality compared with management of these patients in the inclusive trauma system of Victoria, Australia. This study provides further evidence to support efforts to implement such systems.

Using Abbreviated Injury Scale (AIS) codes to classify Computed Tomography (CT) features in the Marshall System.

BACKGROUND: The purpose of Abbreviated Injury Scale (AIS) is to code various types of Traumatic Brain Injuries (TBI) based on their anatomical location and severity. The Marshall CT Classification is used to identify those subgroups of brain injured patients at higher risk of deterioration or mortality. The purpose of this study is to determine whether and how AIS coding can be translated to the Marshall Classification METHODS: Initially, a Marshall Class was allocated to each AIS code through cross-tabulation. This was agreed upon through several discussion meetings with experts from both fields (clinicians and AIS coders). Furthermore, in order to make this translation possible, some necessary assumptions with regards to coding and classification of mass lesions and brain swelling were essential which were all approved and made explicit. RESULTS: The proposed method involves two stages: firstly to determine all possible Marshall Classes which a given patient can attract based on allocated AIS codes; via cross-tabulation and secondly to assign one Marshall Class to each patient through an algorithm. CONCLUSION: This method can be easily programmed in computer softwares and it would enable future important TBI research programs using trauma registry data.

Applying composite performance measures to trauma care.

BACKGROUND: To investigate the association between a number of hospital level composite index methodologies developed from trauma indicators with inhospital mortality. METHODS: Data from January 2001 to December 2006 were extracted from the Victorian State Trauma Registry (Australia) and the Trauma Audit and Research Network (United Kingdom). Three composite methods were explored, including two denominator-based weight approaches and a factor analysis technique. The association between the composite measures and the count of inhospital mortality was investigated using Poisson regression models adjusting for expected deaths per hospital using the Trauma Injury Severity Score methodology. RESULTS: Composite scores were calculated per hospital, per year. The composite score was entered in statistical models as a raw score, and the mortality difference across the central 50% of the composite index was ascertained. In total, 9,218 patients were included and were distributed across 14 hospitals. Composite scores demonstrated an inverse relationship with risk-adjusted inhospital mortality. From the 25th to the 75th percentile of each composite, mortality decreased by 11.99%, 13.58%, and 16.13% (p < 0.05). CONCLUSION: Trauma composite indices demonstrate construct validity when used as measures of hospital level process and represent potentially useful methods of analyzing and reporting quality indicators.

Clinical article: mortality associated with severe head injury in the elderly.

BACKGROUND: Age is an important factor in determining prognosis following severe head injury (SHI), although mortality in patients > or =65 years is poorly reported. The aim of this study was to document mortality in patients with SHI > or =65 years. METHODS: A retrospective analysis of prospectively collected data from the TARN (Trauma Audit and Research Network) database (1996-2004) was performed. Six hundred and sixty-nine patients aged > or =65 with a GCS <9 after a head injury were identified, and mortality at 3 months was recorded. FINDINGS: Mortality was 71% in 65- to 70-year-old patients (n = 137) (CI, 64-79), 75% for patients aged 70-75 years (n = 147) (CI, 68-82), 85% in patients aged 75-80 years (n = 160) (79-91), and 87% for patients >80 years (n = 225) (CI, 83-91). Mortality for all patients > or =65 years with a GCS 3-5 was >80%. A better outcome was observed in patients with a GCS = 6-8 [65-70 years, 47% (CI, 30-64); 70-75 years, 56% (CI, 43-69); 75-80 years, 73% (CI, 62-85); >80 years, 79% (CI, 70-87)]. CONCLUSIONS: SHI-related mortality continues to increase with age. Overall, these data support a conservative approach to the severely head-injured elderly patient; however, patients presenting with a GCS = 6-8 and below the age of 75 may represent a group where more aggressive therapy may be indicated.

Intracranial bleeding in patients with traumatic brain injury: a prognostic study.

BACKGROUND: Intracranial bleeding (IB) is a common and serious consequence of traumatic brain injury (TBI). IB can be classified according to the location into: epidural haemorrhage (EDH) subdural haemorrhage (SDH) intraparenchymal haemorrhage (IPH) and subarachnoid haemorrhage (SAH). Studies involving repeated CT scanning of TBI patients have found that IB can develop or expand in the 48 hours after injury. If IB enlarges after hospital admission and larger bleeds have a worse prognosis, this would provide a therapeutic rationale for treatments to prevent increase in the extent of bleeding. We analysed data from the Trauma Audit & Research Network (TARN), a large European trauma registry, to evaluate the association between the size of IB and mortality in patients with TBI. METHODS: We analysed 13,962 patients presenting to TARN participating hospitals between 2001 and 2008 with a Glasgow Coma Score (GCS) less than 15 at presentation or any head injury with Abbreviated Injury Scale (AIS) severity code 3 and above. The extent of intracranial bleeding was determined by the AIS code. Potential confounders were age, presenting Glasgow Coma Score, mechanism of injury, presence and nature of other brain injuries, and presence of extra-cranial injuries. The outcomes were in-hospital mortality and haematoma evacuation. We conducted a multivariable logistic regression analysis to evaluate the independent effect of large and small size of IB, in comparison with no bleeding, on patient outcomes. We also conducted a multivariable logistic regression analysis to assess the independent effect on mortality of large IB in comparison with small IB. RESULTS: Almost 46% of patients had at some type of IB. Subdural haemorrhages were present in 30% of the patients, with epidural and intraparenchymal present in approximately 22% each. After adjusting for potential confounders, we found that large IB, wherever located, was associated with increased mortality in comparison with no bleeding. We also found that large IB was associated with an increased risk of mortality in comparison with small IB. The odds ratio for mortality for large SDH, IPH and EDH, in comparison with small bleeds, were: 3.41 (95% CI: 2.684.33), 3.47 (95% CI: 2.265.33) and 2.86 (95% CI: 1.864.38) respectively. CONCLUSION: Large EDH, SDH and IPH are associated with a substantially higher probability of hospital mortality in comparison with small IB. However, the limitations of our data, such as the large proportion of missing data and lack of data on other confounding factors, such as localization of the bleeding, make the results of this report only explanatory. Future studies should also evaluate the effect of IB size on functional outcomes.

Using multiple datasets to understand trends in serious road traffic casualties.

Accurate information on the incidence of serious road traffic casualties is needed to plan and evaluate prevention strategies. Traditionally police reported collisions are the only data used. This study investigate the extent to which understanding of trends in serious road traffic injuries is aided by the use of multiple datasets. Health and police datasets covering all or part of Great Britain from 1996-2003 were analysed. There was a significantly decreasing trend in police reported serious casualties but not in the other datasets. Multiple data sources provide a more complete picture of road traffic casualty trends than any single dataset. Increasing availability of electronic health data with developments in anonymised data linkage should provide a better platform for monitoring trends in serious road traffic casualties.

Changing the System - Major Trauma Patients and Their Outcomes in the NHS (England) 2008-17.

BACKGROUND: Trauma care in England was re-organised in 2012 with ambulance bypass of local hospitals to newly designated Major Trauma Centres (MTCs). There is still controversy about the optimal way to organise health series for patients suffering severe injury. METHODS: A longitudinal series of annual cross-sectional studies of care process and outcomes from April 2008 to March 2017. Data was collected through the national clinical audit of major trauma care. The primary analysis was carried out on the 110,863 patients admitted to 35 hospitals that were 'consistent submitters' throughout the study period. The main outcome was longitudinal analysis of risk adjusted survival. FINDINGS: Major Trauma networks were associated with significant changes in (1) patient flow (with increased numbers treated in Major Trauma Centres), (2) treatment systems (more consultant led care and more rapid imaging), (3) patient factors (an increase in older trauma), and (4) clinical care (new massive transfusion policies and use of tranexamic acid). There were 10,247 (9.2%) deaths in the 110,863 patients with an ISS of 9 or more. There were no changes in unadjusted mortality. The analysis of trends in risk adjusted survival for study hospitals shows a 19% (95% CI 3%-36%) increase in the case mix adjusted odds of survival from severe injury over the 9-year study period. Interrupted time series analysis showed a significant positive change in the slope after the intervention time point of April 2012 (+ 0.08% excess survivors per quarter, p = 0.023), in other words an increase of 0.08 more survivors per 100 patients every quarter. INTERPRETATION: A whole system national change was associated with significant improvements in both the care process and outcomes of patients after severe injury. FUNDING: This analysis was carried out independently and did not receive funding. The data collection for the national clinical audit was funded by subscriptions from participating hospitals.

A comparison of European Trauma Registries. The first report from the EuroTARN Group.

UNLABELLED: Trauma management systems have grown in response to regional variations in trauma population, geographical conditions and the provisions of care. National Trauma Registries are being established to improve patient outcomes. However international comparisons could provide the potential to record regional performance, identify and share examples of best practice. To assess whether it was possible to compare data currently being collected by a number of trauma services across Europe, a group was established to develop a common core dataset and to assess the feasibility of collecting anonymised data. METHOD: A series of meetings with European collaborators led to the creation of a group entitled EuroTARN. A website was developed in 2002 and interested parties were invited to submit suggestions for a European dataset using an online version of the Delphi technique. A core dataset was created in 2003 and in 2004 participants were invited to submit a summary of past cases online via the EuroTARN Website. RESULTS: Representatives from 14 countries met and corresponded to create the core dataset. During a trial data collection phase 14 institutions from 11 countries submitted unadjusted mortality data for over 21,500 cases with injury severity Scores of over 15 including information on multiply injured and head injured patients. The results demonstrated that there were observed differences in trauma outcome for similar groups of patients. CONCLUSION: It is possible to collect and collate outcome data from established trauma registries across Europe with minimal additional infrastructure using a web-based system. Initial analysis of the results reveals significant international variations. The network has potential as a source of data for epidemiological and clinical research and for optimal trauma system design across Europe.

Implementing Major Trauma Audit in Ireland.

BACKGROUND: There are 27 receiving trauma hospitals in the Republic of Ireland. There has not been an audit system in place to monitor and measure processes and outcomes of care. The National Office of Clinical Audit (NOCA) is now working to implement Major Trauma Audit (MTA) in Ireland using the well-established National Health Service (NHS) UK Trauma Audit and Research Network (TARN). AIMS: The aim of this report is to highlight the implementation process of MTA in Ireland to raise awareness of MTA nationally and share lessons that may be of value to other health systems undertaking the development of MTA. METHODS: The National Trauma Audit Committee of the Royal College of Surgeons in Ireland, consisting of champions and stakeholders in trauma care, in 2010 advised on the adaptation of TARN for Ireland. In 2012, the Emergency Medicine Program endorsed TARN and in setting up the National Emergency Medicine Audit chose MTA as the first audit project. A major trauma governance group was established representing stakeholders in trauma care, a national project co-ordinator was recruited and a clinical lead nominated. Using Survey Monkey, the chief executives of all trauma receiving hospitals were asked to identify their hospital's trauma governance committee, trauma clinical lead and their local trauma data co-ordinator. Hospital Inpatient Enquiry systems were used to identify to hospitals an estimate of their anticipated trauma audit workload. RESULTS: There are 25 of 27 hospitals now collecting data using the TARN trauma audit platform. These hospitals have provided MTA Clinical Leads, allocated data co-ordinators and incorporated MTA reports formally into their clinical governance, quality and safety committee meetings. There has been broad acceptance of the NOCA escalation policy by hospitals in appreciation of the necessity for unexpected audit findings to stimulate action. CONCLUSION: Major trauma audit measures trauma patient care processes and outcomes of care to drive quality improvement at hospital and national level. MTA will facilitate the strategic development of trauma care in Ireland by monitoring processes and outcomes and the effects of changes in trauma service provision.

Emergency medical services interval and mortality in significant head injury: a retrospective cohort study.

OBJECTIVES: Recent interest has focused on reorganizing emergency medical services (EMS) for English traumatic brain injury (TBI) patients, with bypass of nonspecialist hospitals and direct transportation to distant neuroscience centres. This may expedite specialist neurocritical care and neurosurgical interventions, but risks harms from prehospital deterioration and delayed resuscitation. We therefore aimed to investigate the effect of EMS interval on outcome following head injury. METHODS: We performed a multicentre cohort study examining adult patients with significant TBI (head region abbreviated injury scale ≥3) enrolled in the Trauma Audit and Research Network trauma registry between 2005 and 2011. The association between EMS interval and mortality in patients directly admitted to specialist neuroscience centres was explored using bivariate and multivariate logistic regression and propensity score matching analyses. RESULTS: In all, 7149 eligible patients presented directly to specialist neuroscience centres during the study period. Adjusted odds ratios for mortality showed no association between EMS interval and mortality, varying from 0.46 (95% confidence interval 0.1-2.6) for EMS intervals under 20 min to 0.67 (95% confidence interval 0.4-1.2) for EMS intervals more than 120 min (reference EMS interval 40-60 min). This lack of association was also observed following matching using propensity scores, with no significant difference apparent in mortality between EMS intervals less than 60 min and more than 60 min (17.85 vs. 17.0%, P=0.826). These results were unaffected in sensitivity analyses examining missing covariate data or unmeasured outcomes. CONCLUSION: The lack of observed association between EMS interval and mortality may not preclude bypass of significant TBI patients, with concomitantly prolonged primary transfers from the scene of injury to distant specialist centres. However, given the limitations of registry data, our results should be interpreted with caution.

Systolic hypertension and the response to blunt trauma in infants and children.

OBJECTIVES: To describe age-related systolic blood pressures and pulse rates in children following blunt injury. To compare these variables with standard reference values for uninjured children at rest and with reference ranges from the Advanced Paediatric Life Support (APLS) guidelines. DESIGN: Secondary analysis of a prospective cohort. SETTING: Emergency departments throughout England and Wales. PARTICIPANTS: 12906 children presenting with acute blunt traumatic injury from August 1989 to September 1998. MAIN OUTCOME MEASURES: Systolic blood pressure and pulse rate on arrival. RESULTS: Injured children had higher systolic blood pressures than the standard quoted 'norms'. Standard reference values of systolic blood pressure for children at rest always appeared below the 50th percentile for our cohort of injured children (range 7th-27th percentiles). Pulse rates for children at rest were always towards the mid-range for injured children (range 41st-54th percentiles). These results appeared unrelated to injury severity. Age related APLS reference ranges for systolic blood pressure and pulse rate resembled the standard reference values for uninjured children at rest. CONCLUSIONS: Injured children have a relative systolic hypertension compared with children at rest. Pulse rates in the two groups are comparable. Following injury, children with apparently 'normal' age-specific systolic blood pressures on arrival in the Emergency Department are relatively hypotensive and should be carefully assessed.

The association between admission systolic blood pressure and mortality in significant traumatic brain injury: a multi-centre cohort study.

INTRODUCTION: Low systolic blood pressure (SBP) is an important secondary insult following traumatic brain injury (TBI), but its exact relationship with outcome is not well characterised. Although a SBP of <90 mmHg represents the threshold for hypotension in consensus TBI treatment guidelines, recent studies suggest redefining hypotension at higher levels. This study therefore aimed to fully characterise the association between admission SBP and mortality to further inform resuscitation endpoints. METHODS: We conducted a multicentre cohort study using data from the largest European trauma registry. Consecutive adult patients with AIS head scores >2 admitted directly to specialist neuroscience centres between 2005 and July 2012 were studied. Multilevel logistic regression models were developed to examine the association between admission SBP and 30 day inpatient mortality. Models were adjusted for confounders including age, severity of injury, and to account for differential quality of hospital care. RESULTS: 5057 patients were included in complete case analyses. Admission SBP demonstrated a smooth u-shaped association with outcome in a bivariate analysis, with increasing mortality at both lower and higher values, and no evidence of any threshold effect. Adjusting for confounding slightly attenuated the association between mortality and SBP at levels <120 mmHg, and abolished the relationship for higher SBP values. Case-mix adjusted odds of death were 1.5 times greater at <120 mmHg, doubled at <100 mmHg, tripled at <90 mmHg, and six times greater at SBP<70 mmHg, p<0.01. CONCLUSIONS: These findings indicate that TBI studies should model SBP as a continuous variable and may suggest that current TBI treatment guidelines, using a cut-off for hypotension at SBP<90 mmHg, should be reconsidered.

Comparing model performance for survival prediction using total Glasgow Coma Scale and its components in traumatic brain injury.

The Glasgow Coma Scale (GCS) score is used in clinical practice for patient assessment and communication among clinicians and also in outcome prediction models such as the Trauma and Injury Severity Score (TRIS). The objective of this study is to determine which GCS subscore is best associated with outcome, taking time of assessment into account. Records of patients with brain injury who presented after 1989 were extracted from the Trauma Audit and Research Network (TARN) database. Using logistic regression, a baseline model was derived with age, Injury Severity Score (ISS), and year of injury as covariates and survival at discharge as the dependent variable. Total GCS, its subscores, and their combinations at various time points were separately added to the baseline model to compare their effect on model performance. The dataset contained 21,657 cases. The total GCS score at scene and its subscores had significantly lower predictive power compared with those recorded on arrival at the Emergency Department (ED) (scene total GCS: Area Under the Curve-AUC: 0.89; 95% confidence interval [CI]: 0.89-0.90) and Nagelkerke R(2) of 0.55, admission total GCS: AUC of 0.91; 95% CI: 0.91-0.91, and Nagelkerke R(2) of 0.59). Eye and verbal subscores had significantly lower performances compared with total GCS, motor subscore, and various combinations of subscores. Motor subscore and total GCS appeared to have similar predictive performance (admission total and motor GCS both had AUC of 0.91 (95% CI: 0.91-0.92) and Nagelkerke R(2) of 0.59 and 0.58, respectively). Motor subscore contains most of the predictive power of the total score. GCS on arrival is a significantly better predictor of outcome than that recorded at scene.