Monte carlo method for estimating whole-body injury metrics from pedestrian impact simulation results

The goal of the current study was to develop a method to estimate whole-body injury metrics (WBIMs), which measure the overall impact of injuries, using stochastic injury prediction results from a computational human surrogate. First, hospitalized pedestrian data was queried to identify injuries sustained by pedestrians and their frequencies. Second, with consideration for an understanding of injury mechanisms and the capability of the computational human surrogate, the whole-body was divided into 17 body regions. Then, an injury pattern database was constructed for each body region for various maximum abbreviated injury scale (MAIS) levels. Third, a two-step Monte Carlo sampling process was employed to generate N virtual pedestrians with an assigned list of injuries in AIS codes. Then, the expected values of WBIMs such as injury severity score (ISS), probability of death, whole-body functional capacity index (WBFCI), and lost years of life (LYL), were estimated. Lastly, the proposed method was verified using injury information from the inpatient pedestrian database. Also, the proposed method was applied to pedestrian impact simulations with various impact speeds to estimate the probability of death with respect to the impact speed. The probability of death from the proposed method was compared with those from epidemiological studies. The proposed method accurately estimated WBIMs such as ISS and WBFCI using either for a given distribution of injury risk or MAIS levels. The predicted probability of death with respect to the impact speed showed a good correlation with those from the epidemiological study. These results imply that if we have a human surrogate that can predict the risk of injury accurately, we can accurately estimate WBIMs using the proposed method. The proposed method can simplify a vehicle design optimization process by transforming the multi-objective optimization problem into the single-objective one. Lastly, the proposed method can be applied to other human surrogates such as occupant models.

Characteristics of pedestrian injuries caused due to impacts with powered 2-wheelers in India

Objective: This study aims to understand the nature, severity, and sources of injuries sustained by pedestrians involved in crashes with powered 2-wheelers (PTWs) in India. Further, it aims to understand the pedestrian injury pattern and injury mechanism based on the pedestrian contact location on the PTW. Methods: Eight years of field data from the Road Accident Sampling System-India (RASSI) database were considered for the study. Analyses were performed using both weighted and unweighted RASSI data. A sample of 57 crashes between pedestrians and PTWs was analyzed to determine the pedestrian injury characteristics, pedestrian orientation with PTW, and PTW contact zone (PCZ) or the pedestrian contact location on PTW. The PCZs were classified into 3 types. The risk of sustaining a Maximum Abbreviated Injury Scale (MAIS) injury to the head and pedestrian injury mechanism across the 3 PCZs was analyzed. Results: The results of both weighted and unweighted RASSI data were consistent. About 67% of pedestrians who were killed sustained MAIS 3+ head injuries and 52% of pedestrians with nonfatal injuries sustained MAIS 2+ lower extremity injuries. The risk of MAIS 3+/fatal head injury is notably higher (86%) for pedestrians struck from behind compared to pedestrians struck from the side (36%). Of the 3 PCZs, about 80% of the pedestrians contacting PCZ-1 (corner of the PTW front end) sustained fatal head injuries and only 5% contacting PCZ-2 (center of the PTW front end) sustained fatal head injuries. About 40% contacting PCZ-3 (combination of PCZ-1 and PCZ-2) sustained fatal head injuries. Of all AIS 3+ head injuries, 88% were associated with ground impacts. Of all AIS 2+ lower extremity injuries, 96% were associated with impacts to PTW front-end parts. Conclusions: The results show that head injuries account for most pedestrian fatalities in crashes with PTWs and lower extremity injuries account for most nonfatal injuries. Head injuries are associated with ground contacts and lower extremity injuries are associated with contacting PTW front-end parts. Pedestrians contacting the corner of the PTW are highly prone to MAIS 3+ head injuries, whereas pedestrians contacting the center of the PTW are less prone to MAIS 3+ head injuries. This difference is predominantly because of the varied injury mechanisms seen across PCZs.

Injury patterns within clusters of seriously injured occupants comparing real-world crashes in the United States and the European Union

OBJECTIVE

Crashworthiness assessments in the United States (U.S.) and the European Union (EU) include a large number of safety regulations and consumer testing programs. However, safety standards and testing procedures differ between the two regions. Not much research has been done in relation to this topic, because it has always been assumed that the accident environments in the U.S. and EU are not comparable. The objective of this study is to compare how vehicle occupants are severely injured in motor vehicle collisions in the U.S. and the EU by applying unsupervised learning to accident data.

METHODS

A new methodology to identify clusters of seriously injured occupants in NASS-CDS was proposed by the authors in previous research. The current study goes one step further and uses the clusters to compare the injury patterns at the Maximum Abbreviated Injury Scale (MAIS) 3+ level of passenger vehicle occupants in the U.S. and German accident environments. The clustering model developed with NASS-CDS data is applied in this study to German In-Depth Accident Study (GIDAS) data. A machine learning algorithm automatically assigned each GIDAS case to its most similar NASS-CDS cluster controlling for nine different parameters. Those included the injury severity at the body region level, biomechanical characteristics of the occupants, and technical severity of the crash.

RESULTS

Differences and analogies between GIDAS and NASS-CDS data within clusters of seriously injured occupants are highlighted. One of the clusters groups the collisions with the greatest mass incompatibility in NASS-CDS and GIDAS data. The injury patterns in the clusters that include elderly people match significantly between the U.S. and German data sets. The lack of younger population and elevated body mass index (BMI) values in the GIDAS sample make the injury patterns within these population groups less comparable than in the other clusters.

CONCLUSIONS

Remarkably similar injury patterns at the MAIS 3+ level have been found in U.S. and German accident data sets after controlling for nine different parameters. This research provides evidence to indicate that how belted vehicle occupants are severely injured in the U.S. and in the EU is not necessarily different.

Injury risk curves in far-side lateral motor vehicle crashes by AIS level, body region and injury code

OBJECTIVE

The objective of this study was to develop injury risk curves as a function of change in vehicle velocity for occupants in far-side lateral motor vehicle crashes (MVCs) by AIS level, body region, and specific AIS codes that commonly occur in this crash mode.

METHODS

The National Automotive Sampling System-Crashworthiness Data System (NASS-CDS) years 2000-2015 database was queried, resulting in 4,495 non-weighted far-side crashes. For each case, occupant age, sex, and the following metadata were collected: vehicle model year, vehicle body type, lateral delta-v, normalized PDOF, multiple impacts, belt use, seat position, object contacted, striking vehicle body type, maximum crush extent and side airbag deployment. Multivariable logistic regression was used to develop risk curves for AIS 2+ through 5+ injuries, AIS 2+ injuries by body region (head, thorax, lower extremity), and for each of the 10 most frequent far-side AIS 2+ injuries. Significant covariates were determined by backwards elimination (p < 0.05). The full dataset and a subsampled dataset of only cases with side airbag deployment were used to develop risk curves.

RESULTS

For AIS 2+ through 5+ injury, greater delta-V was associated with greater injury risk (OR's: 2.48-3.66 per 11.9 kph increase) and belt use was associated with lower risk (OR's: 0.04-0.36 compared to unbelted). Multiple impacts were significant predictors of increased AIS 3+, 4+ and 5+ injury risk (OR's: 2.56, 2.27 and 2.83 compared to single impact). For AIS 2+ body region injuries, lateral delta-V and maximum CDC extent were positively associated with increased head, thorax and lower extremity injury risk while belt use was associated with lower risk. Increased lateral delta-v, unbelted status, and greater maximum CDC extent frequently increased injury risk for the most common far-side injuries. Side airbag deployment was not a significant covariate for the injury risk models.

CONCLUSIONS

The resulting risk models expand upon previous literature gaps to provide a more comprehensive view of contributors to injury risk for occupants in far-side MVCs. This study yields risk curves based on the latest available NASS-CDS data.

Estimating near side crash injury risk in best performing passenger vehicles in the United States

The objective of this paper was to develop an injury risk model relating real world injury outcomes in near-side crashes with U.S. New Car Assessment Program (NCAP) test performance, crash, and occupant properties. The study was motivated by the longer-term goal of predicting injury outcomes in a future fleet in which all vehicles are expected to have passive safety performance equivalent to a 5-star NCAP rating level (the highest star rating and lowest risk of injury). The dataset used to evaluate injury risk was the National Automotive Sampling System / Crashworthiness Data System (NASS/CDS). Case years 2010-2015 were used. An injured occupant was defined as a vehicle occupant who experienced an injury of maximum Abbreviated Injury Scale (AIS) of 2 or greater, or who were fatally injured. Injury severity was scored using AIS-2005 (2008 update). Cases were selected in which front-row occupants of late-model vehicles were exposed to a near-side crash. Logistic regression was used to develop an injury model with delta-v, belt status, age, and gender as predictor variables. The side crash performance of each vehicle was identified and added to the model by matching each case with the associated performance in the NCAP moving deformable barrier side impact crash test. NCAP MDB test performance, delta-v, and occupant age, sex, and BMI were found to be significant predictors of injury risk. The effect of a 5 % higher risk in the MDB test (approximately one star rating worse) was comparable to a 2.84 km/h increase in delta-v. This model informs the development of active safety systems in a future fleet where vehicle passive safety performance is higher, quantified by the NCAP MDB test.

Chemoprophylaxis and Venous Thromboembolism in Traumatic Brain Injury at Different Trauma Centers

Patients with severe traumatic brain injury (TBI) are at an increased risk of venous thromboembolism (VTE). Because of concerns of worsening intracranial hemorrhage, clinicians are hesitant to start VTE chemoprophylaxis in this population. We hypothesized that ACS Level I trauma centers would be more aggressive with VTE chemoprophylaxis in adults with severe TBI than Level II centers. We also predicted that Level I centers would have a lower risk of VTE. We queried the Trauma Quality Improvement Program (2010-2016) database for patients with Abbreviated Injury Scale scores of 4 and 5 of the head and compared them based on treating the hospital trauma level. Of 204,895 patients with severe TBI, 143,818 (70.2%) were treated at Level I centers and 61,077 (29.8%) at Level II centers. The Level I cohort had a higher rate of VTE chemoprophylaxis use (43.2% vs 23.3%, P < 0.001) and a shorter median time to chemoprophylaxis (61.9 vs 85.9 hours, P < 0.001). Although Level I trauma centers started VTE chemoprophylaxis more often and earlier than Level II centers, there was no difference in the risk of VTE (P = 0.414) after controlling for covariates. Future prospective studies are warranted to evaluate the timing, safety, and efficacy of early VTE chemoprophylaxis in severe TBI patients.

Development of an expert derived ICD-AIS map for serious AIS3+ injury identification

Objective: The objective of the mapping project was to develop an expert derived map between the International Statistical Classification of Diseases and Related Health Problems (ICD) clinical modifications (CM) and the Abbreviated Injury Scale (AIS) to be able to relate AIS severity to ICD coded data road traffic collision data in EU datasets. The maps were developed to enable the identification of serious AIS3+ injury and provide details of the mapping process for assumptions to be made about injury severity from mass datasets. This article describes in detail the mapping process of the International Classification of Diseases Ninth Revision, Clinical Modification (ICD-9-CM) and the International Classification of Diseases Tenth Revision, Clinical Modification (ICD-10-CM) codes to the Abbreviated Injury Scale 2005, Update 2008 (AIS08) codes to identify injury with an AIS severity of 3 or more (AIS3+ severity) to determine 'serious' (MAIS3+) road traffic injuries.Methods: Over 19,000 ICD codes were mapped from the following injury categories; injury ICD-9-CM (Chapter 17) codes between '800 and 999.9' and injury ICD-10-CM (Chapter 19) 'S' and 'T' prefixed codes were reviewed and mapped to an AIS08 category and then relate the severity to three groups; AIS3+, AIS < =2 and AIS 9 (no-map). The mapping was undertaken by ICD coding experts and certified AIS specialists from Europe, North America, Australia and Canada in face-to-face working groups and subsequent webinars between May 2014 and October 2015. During the process, the business rules were documented to define guidelines for the mapping process and enable inter-rater discrepancies to be resolved.Results: In total 2,504 ICD-9-CM codes were mapped to the AIS, of which 780 (31%) were assigned an AIS3+ severity. For the16,508 ICD-10-CM mapped codes a total of 2,323 (14%) were assigned an AIS3+ severity. Some 17% (n = 426) and 27% (n = 4,485) of ICD-9-CM and ICD-10-CM codes respectively were assigned to AIS9 (no-map) following the mapping process. It was evident there were 'problem' codes that could not be easily mapped to an AIS code to reflect severity. Problem maps affect the specificity of the map and severity when used to translate historical data in large datasets.Conclusions: The Association for the Advancement in Automotive Medicine, AAAM-endorsed expert-derived map offers a unique tool to road safety researchers to establish the number of MAIS3+ serious injuries occurring on the roads. The detailed process offered in this paper will enable researchers to understand the decision making and identify limitations when using the AIS08/ICD map on country-specific data. The results could inform protocols for dealing with problem codes to enable country comparisons of MAIS3+ serious injury rates.

Damage to the eye and optic nerve in seriously traumatized patients with concomitant head injury: analysis of 84,627 cases from the TraumaRegister DGU® between 2002 and 2015

BACKGROUND

To determine the prevalence and characteristics of prechiasmatic visual system injuries (VSI) among seriously injured patients with concomitant head trauma in Europe by means of a multinational trauma registry.

METHODS

The TraumaRegister DGU® was searched for patients suffering from serious trauma with a Maximum Abbreviated Injury Scale (AIS) ≥ 3 between 2002 and 2015 in Europe. After excluding cases without significant head injury defined by an AIS ≥ 2, groups were built regarding the existence of a concomitant damage to the prechiasmatic optic system comprising globe and optic nerve. Group comparisons were performed with respect to demographic, etiological, clinical and outcome characteristics.

RESULTS

2.2% (1901/84,627) of seriously injured patients with concomitant head trauma presented with additional VSI. These subjects tended to be younger (mean age 44.7 versus 50.9 years) and were more likely of male gender (74.8% versus 70.0%) compared to their counterparts without VSI. The most frequent trauma etiologies were car accidents in VSI patients (28.5%) and falls in the control group (43.2%). VSI cases were prone to additional soft tissue trauma of the head, skull and orbit fractures as well as pneumocephalus. Primary treatment duration was significantly longer in the VSI cohort (mean 23.3 versus 20.5 days) along with higher treatment costs and a larger proportion of patients with moderate or severe impairment at hospital discharge despite there being a similar average injury severity at admission in both groups.

CONCLUSIONS

A substantial proportion of patients with head injury suffers from additional VSI. The correlation between VSI and prolonged hospitalization, increased direct treatment expenditures, and having a higher probability of posttraumatic impairment demonstrates the substantial socioeconomic relevance of these types of injuries.

Estimated crash injury risk and crash characteristics for motorsport drivers

OBJECTIVE

Motorsport crash events are complex and driver restraint systems are unique to the motorsport environment. The National Association for Stock Car Auto Racing, Incorporated (NASCAR®) crash and medical datasets provide an opportunity to assess crash statistics and the relationship between crash characteristics and driver injury. Injury risk curves can estimate driver injury risk and can be developed using vehicle incident data recorder information as inputs. These relationships may provide guidance and insight for at-track emergency response, driver triage and treatment protocols.

METHOD

Eight race seasons of crash and medical record data (including Association for the Advancement of Automotive Medicine Abbreviated Injury Scale (AIS) scores) from the Monster Energy NASCAR Cup Series & NASCAR Xfinity Series were processed and analyzed. Multiple logistic regression modeling was used to produce injury risk curves from longitudinal and lateral resultant change in velocity, resultant peak acceleration, principal direction of force and the number of impacts per incident.

RESULTS

2065 Unique IDR data files were matched with 246 cases of driver injury or sub-injury (severity below AIS 1) and 1819 no-injury cases. Multiple logistic regression modeling showed increasing resultant change in velocity, resultant peak acceleration and the number of impacts during a crash event all increase estimated driver injury risk. After accounting for the other predictors in the model, right lateral impacts were found to have a lower estimated injury risk. The model produced an Area Under the Receiver Operating Characteristics curve of 0.80. Across the eight race seasons in this study the overall average resultant change in velocity was 34.4 kph (21.4 mph) and the average resultant peak acceleration was 19.0 G for an average of 258 crashes per season. For 2011 through 2015, full time drivers experienced 134 times more crashes per mile traveled than passenger vehicles, but experienced 9.3 times fewer injuries per crash.

CONCLUSION

Multiple logistic regression was used to estimate AIS 1+ injury only and AIS 1+ with sub-injury risk for motorsport drivers using motorsport-specific crash and medical record databases. The injury risk estimate models can provide future guidance and insight for at-track emergency medical response dispatch immediately following an on-track crash. These models may also inform future driver triage protocols and influence future expenditures on motorsports safety research.

Descriptive analysis of the effect of back protector on the prevention of vertebral and thoracolumbar injuries in serious motorcycle accident

CONTEXT AND OBJECTIVE

Among the different products and protective gear used by riders of two-wheeled motorized vehicles, back protectors that are designed to prevent damage to the spinal column are widely used today compared other protections. However, few studies measure their effectiveness. Can their effectiveness be measured? How do they help decrease or change the nature of thoracolumbar traumas that occur? To address these questions and remedy the lack of objective data regarding these products, an epidemiological, clinical, and biomechanical analysis of motorcycle riders who were admitted to a French trauma center after an accident was performed. So, this study investigates the effectiveness of back protectors, including their ability to prevent specific mechanisms of thoracic and lumbar spinal injuries related to TWMV accidents.

METHOD

A questionnaire was administered to victims of accidents involving two-wheeled motorized vehicles who were admitted to the trauma room at the Marseille trauma center over the course of 2016. Collect data are related to the victim, the accident scenario, and a detailed description of the observed injuries using AIS (Abbreviated Injury Scale) coding and Magerl classification. Univariate analyses and Fisher tests were performed for victims who were or were not wearing back protectors.

RESULTS

This study collected data from 124 victims. Almost half of the victims were wearing a back protector at the time of the accident (53 victims, thus 43% of riders). Collectively, twenty-nine victims who were wearing back protectors had 57 thoracolumbar injuries, and twenty eight victims who were not wearing back protectors had 75 thoracolumbar lesions. The results from this study show that there is no significant difference in the nature and mechanism of thoracolumbar injuries as a function of back protection. The majority of the thoracolumbar injuries were not severe. They were primarily bone injuries, essentially compression fractures, regardless of whether a back protector was worn.

CONCLUSION

This study shows that the use of back protection does not decrease the number, type, or mechanism of thoracolumbar injuries associated with accidents involving two-wheeled motorized vehicles. However, it suggests that lumbar vertebral injuries are deflected towards the thoracic vertebrae when back protectors are worn. Finally, it suggests that the design of back protectors should be reconsidered to better protect riders from what are referred to as compression fractures (craniocaudal force), which remain the primary form of fracture regardless of the rider's characteristics, based on the data analyzed.

Incidence, Risk Factors, and Outcomes of Ventilator-Associated Pneumonia in Traumatic Brain Injury: A Meta-analysis

Ventilator-associated pneumonia (VAP) is one of the most severe complications in patients with traumatic brain injury (TBI) and is considered a risk factor for poor outcomes. However, the incidence of VAP among patients with TBI reported in studies varies widely. What is more, the risk factors and outcomes of VAP are controversial. This study estimates the incidence, risk factors, and outcomes of VAP in patients with TBI and provides evidence for prevention and treatment. PubMed, EMBASE, Cochrane Library, and Web of Science databases were searched from the earliest records to May 2018. Data involving the incidence, risk factors, and outcomes were extracted for meta-analysis. The results showed that the incidence of VAP was 36% (95% confidence interval (CI) 31-41%); risk factors analyses showed that smoking [odds ratio (OR) 2.13; 95% CI 1.16-3.92], tracheostomy (OR 9.55; 95% CI 3.24-28.17), blood transfusion on admission (OR 2.54; 95% CI 1.24-5.18), barbiturate infusion (OR 3.52; 95% CI 1.68-7.40), injury severity score (OR 4.65; 95% CI 1.96-7.34), and head abbreviated injury scale (OR 2.99; 95% CI 1.66-5.37) were related to the occurrence of VAP. When patients developed VAP, mechanical ventilation time (OR 5.45; 95% CI 3.78-7.12), ICU length of stay (OR 6.85; 95% CI 4.90-8.79), and hospital length of stay (OR 10.92; 95% CI 9.12-12.72) were significantly increased. However, VAP was not associated with an increased risk of mortality (OR 1.28; 95% CI 0.74-2.21). VAP is common in patients with TBI. It is affected by a series of factors and has a poor prognosis.

Clinical guided computer tomography decisions are advocated in potentially severely injured trauma patients: a one-year audit in a level 1 trauma Centre with long pre-hospital times

BACKGROUND

The International Commission on Radiological Protection's (ICRP) justification principles state that an examination is justified if the potential benefit outweighs the risk for radiation harm. Computer tomography (CT) contributes 50% of the radiation dose from medical imaging, and in trauma patients, the use of standardized whole body CT (SWBCT) increases. Guidelines are lacking, and reviews conclude conflictingly regarding the benefit. We aimed to study the degree of adherence to ICRP's level three justification, the individual dose limitation principle, in our institution.

METHODS

This is a retrospective clinical audit. We included all 144 patients admitted with trauma team activation to our regional Level 1 trauma centre in 2015. Injuries were categorized according to the Abbreviated Injury Scale (AIS) codes. Time variables, vital parameters and interventions were registered. We categorized patients into trauma admission SWBCT, selective CT or no CT examination strategy groups. We used descriptive statistics and regression analysis of predictors for CT examination strategy.

RESULTS

The 144 patients (114 (79.2%) males) had a median age of 31 (range 0-91) years. 105 (72.9%) had at least one AIS ≥ 2 injury, 26 (18.1%) in more than two body regions. During trauma admission, at least one vital parameter was abnormal in 46 (32.4%) patients, and 73 (50.7%) underwent SWBCT, 43 (29.9%) selective CT and 28 (19.4%) no CT examination. No or only minor injuries were identified in 17 (23.3%) in the SWBCT group. Two (4.6%) in the selective group were examined with a complement CT, with no new injuries identified. A significantly (p < 0.001) lower proportion of children (61.5%) than adults (89.8%) underwent CT examination despite similar injury grades and use of interventions. In adjusted regression analysis, patients with a high-energy trauma mechanism had significantly (p = 0.028) increased odds (odds ratio = 4.390, 95% confidence interval 1.174-16.413) for undergoing a SWBCT.

CONCLUSION

The high proportion of patients with no or only minor injuries detected in the SWBCT group and the significantly lower use of CT among children, indicate that use of a selective CT examination strategy in a higher proportion of our patients would have approximated the ICRP's justification level three, the individual dose limitation principle, better.

Characteristics of bicycle crashes among children and the effect of bicycle helmets

Objective: Focusing on children (0-17 years), this study aimed to investigate injury and accident characteristics for bicyclists and to evaluate the use and protective effect of bicycle helmets.Method: This nationwide Swedish study included children who had visited an emergency care center due to injuries from a bicycle crash. In order to investigate the causes of bicycle crashes, data from 2014 to 2016 were analyzed thoroughly (n = 7967). The causes of the crashes were analyzed and categorized, focusing on 3 subgroups: children 0-6, 7-12, and 13-17 years of age. To assess helmet effectiveness, the induced exposure approach was applied using data from 2006 to 2016 (n = 24,623). In order to control for crash severity, only bicyclists who had sustained at least one Abbreviated Injury Scale (AIS) 2+ injury (moderate injury or more severe) in body regions other than the head were included.Results: In 82% of the cases the children were injured in a single-bicycle crash, and the proportion decreased with age (0-6: 91%, 7-12: 84%, 13-17: 77%). Of AIS 2+ injuries, 8% were head injuries and 85% were injuries to the extremities (73% upper extremities and 13% lower extremities). Helmet use was relatively high up to the age of 10 (90%), after which it dropped. Helmets were much less frequently used by teenagers (14%), especially girls. Consistently, the share of head injuries increased as the children got older. Bicycle helmets were found to reduce all head injuries by 61% (95% confidence interval [CI], 10: +/- 10%) and AIS 2+ head injuries by 68% (95% CI, 12: +/- 12%). The effectiveness in reducing face injuries was lower (45% CI +/- 10% for all injuries and 54% CI +/- 32% for AIS2+ injuries).Conclusions: This study indicated that bicycle helmets effectively reduce injuries to the head and face. The results thus point to the need for actions aimed at increasing helmet use, especially among teenagers. Protective measures are necessary to further reduce injuries, especially to the upper extremities.

Impact of Adapting the Abbreviated Injury Scale (AIS)-2005 from AIS-1998 on Injury Severity Scores and Clinical Outcome

BACKGROUND

In recent years, several versions of the Abbreviated Injury Scale (AIS) were updated and published. It was reported that the codeset in the dictionary of AIS-2005 had significant change from that of AIS-1998. This study was designed to evaluate the potential impact of adapting the AIS-2005 codeset from the AIS-1998 in an established trauma system of a single level I trauma center. The patients' outcome was measured in different Injury Severity Score (ISS) strata according to the double-coded injuries in a three-year period.

METHODS

The double-coded injuries sustained by 7520 trauma patients between 1 January, 2016, and 31 December, 2018, in a level I trauma center were used to compare the patient injury characteristics and outcomes between AIS-1998 and AIS-2005 and under different ISS strata, defined as <16 (mild to moderate injury), 16-24 (severe injury), and >24 (critical injury).

RESULTS

The mean ISS was significantly lower using AIS-2005 than using AIS-1998 (7.5 ± 6.3 vs. 8.3 ± 7.1, respectively, p < 0.001). AIS-2005 scores in the body regions of the head/neck (2.94 ± 1.08 vs. 3.40 ± 1.15, respectively, p < 0.001) and extremity (2.19 ± 0.56 vs. 2.24 ± 0.58, respectively, p < 0.001), but not in other body regions, were significantly lower than AIS-1998 scores. The critically injured patients (ISS >24), but not severely injured patients or patients with mild-to-moderate injury, coded by AIS-2005 had a significantly higher mortality rate (34.2% vs. 26.2%, respectively, p = 0.031) than did patients coded by AIS-1998. The rate of intensive care unit admission was significantly higher for patients in all ISS strata after adapting AIS-2005 as the scoring system than after adapting AIS-1998. Regarding patients with major trauma, which was defined as ISS > 15, the number of patients with major trauma in this study was 17.0% (n = 1276) for AIS-1998 and 9.7% (n = 733) for AIS-2005. As a consequence, the mortality rate of patients with major trauma was significantly higher in AIS-2005 than in AIS-1998 (15.4% vs. 9.1%, respectively, p < 000.1).

CONCLUSIONS

In this study, we revealed that the adaptation of AIS-2005 from AIS-1998 had resulted in a significant decrease of severity scores in the measurement of the same injuries. The number of head/neck injuries classified as 16-24 was the key difference between AIS-1998 and AIS-2005. Furthermore, critically injured patients who had ISS > 24 coded by AIS-2005 had significantly higher mortality rates than did the patients coded by AIS-1998. This study also indicated that a direct comparison of the measurements that are generated from these two AIS versions can produce misleading results.

Unexpected ICU Admission Is Associated with Pulmonary Complications but Not Increased Mortality; Rescue Is Essential for Optimal Patient Outcome

ICU beds are in demand in large regional referral hospitals; therefore, nonintubated polytrauma patients are often admitted to general care (GC) wards. We hypothesized that trauma patients with Injury Severity Score (ISS) greater than 15 and unexpected ICU admission (U-ICU) after initial admission to GC had increased morbidity and mortality. We also hypothesized that those requiring U-ICU could be predicted based on admission parameters. This was a retrospective review of patients aged at least 18 years, admitted to GC with blunt trauma and ISS greater than 15 from April 2015 to March 2017. Demographics were collected along with injury patterns and complications. Statistics included chi-squared, Fisher's exact, Mann-Whitney, and t tests. Of 986 patients, 502 (50.9%) were directly admitted to GC. Prevalence of U-ICU was 9.8 per cent (49/502 patients). The only admission predictor of U-ICU was a history of myocardial infarction (8/49, 16.3%, vs 21/453, 4.6%, P = 0.001). Those with U-ICU had increased incidence of pneumonia, acute respiratory distress syndrome, and endotracheal intubation compared with GC, but there was no difference in overall mortality (3/49, 6.1% vs 18/453, 4.0%, P = 0.45). Half of all severely injured, nonintubated patients can be managed on the GC ward; however, 9.8 per cent of patients will require U-ICU admission for pulmonary complications. Admission history of myocardial infarction predicts those at risk. Severely injured patients with U-ICU admission have significant cardiopulmonary complications, but can be rescued with no increase in overall mortality.

Limitations of the European barrier crash testing regulation relating to occupant safety

The safety of roadside restraint systems in Europe is ensured by the EN 1317 regulation. The ability of the barrier to mitigate injury to the occupants of vehicles is tested according to two occupant injury metrics: Acceleration Severity Index (ASI) and Theoretical Head Impact Velocity (THIV). Both metrics aim to predict occupant head injury from vehicle kinematics, despite the potential to easily measure actual head kinematics from instrumented Anthropomorphic Test Dummies, a non-instrumented version of which is already required according to the regulation. Retrospective data provided by AISICO S.r.l. for 33 certificated barrier tests, where acceleration of the dummy's head had also been recorded, were re-analysed. ASI and THIV were compared with Head Injury Criterion (HIC₁₅) and Neck injury Criterion (N_ij), as well as corresponding Real Head Impact Velocity (RHIV) values. Three barriers presented HIC₁₅ values above the threshold used in crashworthiness testing, two of which corresponded to fatal injury according to the Abbreviated Injury Scale. One barrier presented an N_ij value corresponding to a 30% risk of neck injury. RHIV values were above the regulation threshold in 15% of tests, but were not significantly different from the corresponding THIV values. It was concluded that vehicle kinematics do not accurately predict head kinematics during barrier testing. The presented data indicate the current EN 1317 regulation was not capable of detecting all potential dangerous outcomes, with the potential to underestimate occupant risk. Further investigation is necessary to devise suitable indices based on actual head and neck data. These data would be obtained from a dummy instrumented with both a head accelerometer and neck load cell and, possibly, a gyroscope. To consistently test the true worst-case scenario, the tested side window should be closed and non-reinforced.

Initial chest X-ray in multiple trauma patients: Still works!

OBJECTIVE

Blunt thoracic aortic injury is life-threatening injury. High suspicion on this clinical condition can be made by initial chest X-ray on emergency department. The aim of study was to detect which other signs, except widened mediastinum, are specific for rupture of the thoracic aorta.

METHODS

To the study were included all Triage positive patients primary headed from the scene of injury to the Trauma center Level I from January to December 2014 and which have performed chest X-ray on emergency department followed by CT of chest, abdomen and pelvis. On chest X-ray were evaluated diameter of superior mediastinum, deviation of trachea, deviation of left and right main bronchus, aortic arch, fracture of first or second rib on the left side and obliteration of aortopulmonary space.

RESULTS

Totally n=208 patients were enrolled to the study. Seven patients had blunt thoracic aortic injury on CT angiography. All these patients had widened superior mediastinum more than 80 mm (p=0.021). Six patients with blunt thoracic aortic injury had obliteration of aortic arch (p=0.0001) and obliteration of aortopulmonary space (p=0.0001).

CONCLUSION

All patients after high energy trauma with widened mediastinum together with obliteration of aortic arch and obliteration of aortopulmonary space on initial chest X-ray without initial CT, must be indicated to the CT after initial stop the bleeding procedures for the exclusion of traumatic rupture of thoracic aorta.

Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) for Severe Torso Trauma in Japan: A Descriptive Study

BACKGROUND

Resuscitative endovascular balloon occlusion of the aorta (REBOA) has the potential to be an alternative to open aortic cross-clamping (ACC). However, its practical indication remains unknown. We examined the usage trend of REBOA and ACC in Japan for severe torso trauma and investigated whether these procedures were associated with the time of death distribution based on a large database from the Japan Trauma Data Bank (JTDB).

METHODS

The JTDB from 2004 to 2014 was reviewed. Eligible patients were restricted to those with severe torso trauma, which was defined as an abbreviated injury scale score of ≥4. Patients were classified into groups according to the aortic occlusion procedures. The primary outcomes were the rates of REBOA and ACC use according to the clinical situation. We also evaluated whether the time of death distribution for the first 8 h differed based on these procedures.

RESULTS

During the study period, a total of 21,533 patients met our inclusion criteria. Overall, REBOA was more commonly used than ACC for patients with severe torso trauma (2.8% vs 1.5%). However, ACC was more frequently used in cases of thoracic injury and cardiac arrest. Regarding the time of death distribution, the cumulative curve for death in REBOA cases was elevated much more slowly and mostly flat for the first 100 min.

CONCLUSIONS

REBOA is more commonly used compared to ACC for patients with severe torso trauma in Japan. Moreover, it appears that REBOA influences the time of death distribution in the hyperacute phase.

Acute Adverse Events After Spinal Cord Injury and Their Relationship to Long-term Neurologic and Functional Outcomes: Analysis From the North American Clinical Trials Network for Spinal Cord Injury

OBJECTIVES

There are few contemporary, prospective multicenter series on the spectrum of acute adverse events and their relationship to long-term outcomes after traumatic spinal cord injury. The goal of this study is to assess the prevalence of adverse events after traumatic spinal cord injury and to evaluate the effects on long-term clinical outcome.

DESIGN

Multicenter prospective registry.

SETTING

Consortium of 11 university-affiliated medical centers in the North American Clinical Trials Network.

PATIENTS

Eight-hundred one spinal cord injury patients enrolled by participating centers.

INTERVENTIONS

Appropriate spinal cord injury treatment at individual centers.

MEASUREMENTS AND MAIN RESULTS

A total of 2,303 adverse events were recorded for 502 patients (63%). Penalized maximum logistic regression models were fitted to estimate the likelihood of neurologic recovery (ASIA Impairment Scale improvement ≥ 1 grade point) and functional outcomes in subjects who developed adverse events at 6 months postinjury. After accounting for potential confounders, the group that developed adverse events showed less neurologic recovery (odds ratio, 0.55; 95% CI, 0.32-0.96) and was more likely to require assisted breathing (odds ratio, 6.55; 95% CI, 1.17-36.67); dependent ambulation (odds ratio, 7.38; 95% CI, 4.35-13.06) and have impaired bladder (odds ratio, 9.63; 95% CI, 5.19-17.87) or bowel function (odds ratio, 7.86; 95% CI, 4.31-14.32) measured using the Spinal Cord Independence Measure subscores.

CONCLUSIONS

Results from this contemporary series demonstrate that acute adverse events are common and are associated with worsened long-term outcomes after traumatic spinal cord injury.

Rib Fractures and Mortality: Breaking the Causal Relationship

Rib fractures have long been considered as a major contributor to mortality in the blunt trauma patient. We hypothesized that rib fractures can be an excellent predictor of mortality, but rarely contribute to cause death. We performed a retrospective study (2008-2015) of blunt trauma patients admitted to our urban, Level I trauma center with one or more rib fractures. Medical records were reviewed in detail. Rib fracture deaths were those from any respiratory sequelae or hemorrhage from rib fractures. There were 4413 blunt trauma patients who sustained one or more rib fractures and 295 (6.8%) died. Rib fracture patients who died had a mean Injury Severity Score = 38 and chest Abbreviated Injury Score = 3.4. Rib fractures were the cause of death in only 21 patients (0.5%). After excluding patients who were dead on arrival, patients dying as a result of their rib fractures were found to be older (P < 0.0001) and had a higher admission respiratory rate (P = 0.02). Multivariable logistic regression found that age ≥65 was the only variable independently associated with mortality directly related to rib fractures (odds ratio 4.1, 95% confidence interval = 1.3-13.3, P value < .0001). Mortality in patients with rib fractures is uncommon (7%), and mortality directly related to rib fractures is rare (0.5%). Older patients are four times more likely to die as a direct result of rib fractures and may require additional resources to avoid mortality.

Comparing consequences of using two different definitions for body regions for the improvement of personal protective equipment for powered two-wheelers

Objective: Various definitions and uses of the term body region can be found in the literature. A definition of body regions using the Abbreviated Injury Scale (AIS) codes not strictly aligned with AIS chapters was developed for use in the European Commission-funded PIONEERS project (Protective Innovations of New Equipment for Enhanced Rider Safety). This work aims to examine the consequences of differently defined body regions on injury priority ranking using the percentage of patients showing at least moderate injury severity (AIS 2+) per regarded body region.Methods: Three different crash investigation data sets of injured riders and/or pillion riders of powered 2-wheelers (PTWs) were used for this analysis. The first contained data for 143 fatalities, the second contained data for 58 severely injured, and the last for contained data for 982 patients from a sample that was close to national representativeness. Frequency of injury was examined using body regions based on the AIS chapters (and first digit of the AIS Unique Identifier) and based on the PIONEERS definition.Results: Though different body region definitions did not result in different top-ranked body regions in terms of injury frequency, different definitions did provide different levels of information that impact priority within AIS chapter-defined regions. For PTW riders, cervical injuries are the highest priority spinal injuries. Thoracic and lumbar spinal injuries seem to occur together with other injuries in the thorax and abdominal region. Severe lower extremity injuries frequently involve the pelvis and the leg.Conclusions: Body regions need to be defined carefully to avoid misinterpretations. Publications that use body regions for their analysis to present injury frequencies should clearly define what they include in each region.

Factors associated with chest injuries to front seat occupants in frontal impacts

Objective: Frontal impact chest protection in European cars has been highlighted as an area where possible improvements could be made. The chest is particularly vulnerable in older occupants whose numbers are forecast to increase significantly in the coming decades. This study aimed to provide some direction to areas for possible improvements in frontal crash chest protection.Methods: Real-world crash injury data were interrogated, focusing on cars with current restraint components. The research examined belted front seat occupants in frontal impacts where airbags, pretensioners, and load limiters were present.Results: The chest was the most often injured body region at Abbreviated Injury Scale (AIS) 2+, 3+, and 4+ injury levels. The rate of AIS 2+ and AIS 3+ chest injuries was highest among elderly occupants and lowest among young occupants, and elderly occupants sustained proportionally more severe chest injuries in low/moderate-speed impacts compared to young and middle-aged occupants. However, it should be noted that rates of AIS 2 chest injury were also significantly higher for middle-aged occupants compared to the young. The front passenger seat was shown to be more often associated with significant chest injury than the driver seat. The higher proportion of elderly female occupants was postulated as a reason for this. Skeletal injury was the most frequent type of AIS 2+ chest injury, and the rate of injury for elderly occupants with such injuries was higher than that for young and middle-aged occupants. With the increase in the number of rib fractures, the risk of pulmonary complications and organ injuries tended to increase. The major cause of chest injury was identified as restraining loads transmitted to the chest via the seat belt. The absence of intrusion in the majority of cases suggests an opportunity for the restraint system to better manage the crash pulse, not only for elderly occupants but for those who are middle-aged as well.Conclusions: This study shows the necessity for safety interventions, through new vehicle crashworthiness systems, to improve chest protection, especially for middle-aged and elderly car occupants. Deployment of appropriate injury risk criteria, use of an appropriate dummy thorax, development of a low-energy restraint test, and the development of more adaptive restraints have been discussed as possible solutions to the problem.

Examining correlations between motorcyclist's conspicuity, apparel related factors and injury severity score: Evidence from new motorcycle crash causation study

Motorcyclists are vulnerable road users at a particularly high risk of serious injury or death when involved in a crash. In order to evaluate key risk factors in motorcycle crashes, this study quantifies how different "policy-sensitive" factors correlate with injury severity, while controlling for rider and crash specific factors as well as other observed/unobserved factors. The study analyzes data from 321 motorcycle injury crashes from a comprehensive US DOT FHWA's Motorcycle Crash Causation Study (MCCS). These were all non-fatal injury crashes that are representative of the vast majority (82%) of motorcycle crashes. An anatomical injury severity scoring system, termed as Injury Severity Score (ISS), is analyzed providing an overall score by accounting for the possibility of multiple injuries to different body parts of a rider. An ISS ranges from 1 to 75, averaging at 10.32 for this sample (above 9 is considered serious injury), with a spike at 1 (very minor injury). Preliminary cross-tabulation analysis mapped ISS to the Abbreviated Injury Scale (AIS) injury classification and examined the strength of associations between the two. While the study finds a strong correlation between AIS and ISS classification (Kendall's tau of 0.911), significant contrasts are observed in that, when compared to ISS, AIS tends to underestimate the severity of an injury sustained by a rider. For modeling, fixed and random parameter Tobit modeling frameworks were used in a corner-solution setting to account for the left-tail spike in the distribution of ISS and to account for unobserved heterogeneity. The developed random parameters Tobit framework additionally accounts for the interactive effects of key risk factors, allowing for possible correlations among random parameters. A correlated random parameter Tobit model significantly out-performed the uncorrelated random parameter Tobit and fixed parameter Tobit models. While controlling for various other factors, we found that motorcycle-specific shoes and retroreflective upper body clothing correlate with lower ISS on-average by 5.94 and 1.88 units respectively. Riders with only partial helmet coverage on-average sustained more severe injuries, whereas, riders with acceptable helmet fit had lower ISS Methodologically, not only do the individual effects of several key risk factors vary significantly across observations in the form of random parameters, but the interactions between unobserved factors characterizing random parameters significantly influence the injury severity score as well. The implications of the findings are discussed.

Trauma Team Activation at a Level I Trauma Center in Southern California: Time of Day Matters

The ACS Committee on Trauma specifies prehospital criteria that trigger trauma team activation (TTA). The study aims to define the relationship between TTA and time of day, mechanism of injury, and need for operative intervention. All trauma patients presenting to LAC+USC (January 2008-July 2018) after triggering TTA were screened. Patients were excluded if time of ED arrival was undocumented. Demographics, injury data, and outcomes were analyzed. After exclusions (<1%), 54,826 patients were enrolled. The median age was 35 [IQR 23-53]. The median Injury Severity Score was 4 [1-10]. The most common mechanisms of injury were falls (n = 14,166; 31%), auto versus pedestrian collisions (n = 11,921; 26%), and motor vehicle collisions (n = 11,024; 24%). Penetrating trauma comprised 16 per cent (n = 8,686). The busiest hour for TTAs was 19:00 to 20:00, although penetrating trauma was most common between 23:00 and 01:00. Emergent surgical intervention in absolute numbers was most frequent between 20:00 and 01:00. As a proportion of the number of TTAs per hour, emergent operative intervention was most frequent between 23:00 and 06:00. In conclusion, the volume of TTAs and the triggering mechanism of injury vary significantly by time of day. The need for operative intervention is highest overnight. This information can be used to help increase hospital preparedness and allocate resources accordingly.

Age-based differences in the disability of extremity injuries in pediatric and adult occupants

Objective: The objective was to develop a disability-based metric for motor vehicle crash (MVC) upper and lower extremity injuries and compare functional outcomes between children and adults.Methods: Disability risk (DR) was quantified using Functional Independence Measure (FIM) scores within the National Trauma Data Bank-Research Data System for the top 95% most frequently occurring Abbreviated Injury Scale (AIS) 3 extremity injuries (22 unique injuries). Pediatric (7-18 years), young adult (19-45 years), middle-aged (46-65 years), and older adult (66+ years) MVC occupants with an FIM score and at least one of the 22 extremity injuries were included. DR was calculated for each injury as the proportion of occupants who were disabled of those sustaining the injury. A maximum AIS-adjusted disability risk (DR_MAIS) was also calculated for each injury, excluding occupants with AIS 4+ co-injuries.Results: Locomotion impairment was the most frequent disability type across all ages. DR and DR_MAIS of the extremity injuries ranged from 0.06 to 1.00 (6%-100% disability risk). Disability risk increased with age, with DR_MAIS increasing from 25.9% ± 8.6% (mean ± SD) in pediatric subjects to 30.4% ± 6.3% in young adults, 39.5% ± 6.6% in middle-aged adults, and 60.5 ± 13.3% in older adults. DR_MAIS for upper extremity fractures differed significantly between age groups, with higher disability in older adults, followed by middle-aged adults. DR_MAIS for pelvis, hip, shaft, knee, and other lower extremity fractures differed significantly between age groups, with older adult DR_MAIS being significantly higher for each fracture type. DR_MAIS for hip and lower extremity shaft fractures was also significantly higher in middle-aged occupants compared to pediatric and young adult occupants. The maximum AIS-adjusted mortality risk (MR_MAIS, proportion of fatalities among occupants sustaining an MAIS 3 injury) was not correlated with DR_MAIS for extremity injuries in pediatric, young adult, middle-aged, and older adult occupants (all R² < 0.01). Disability associated with each extremity injury was higher than mortality risk.Conclusions: Older adults had significantly greater disability for MVC extremity injuries. Lower disability rates in children may stem from their increased physiological capacity for bone healing and relative lack of bone disease. The disability metrics developed can supplement AIS and other severity-based metrics by accounting for the age-specific functional implications of MVC extremity injuries.