Modulation of the Redox Expression and Inflammation Response in the Critically Ill Polytrauma Patient with Thoracic Injury. Statistical Correlations between Antioxidant Therapy

BACKGROUND

One of the major causes of mortality in the world is represented by multiple traumas. Thoracic trauma is commonly associated with polytraumas. A series of physiopathological complications follow polytraumas, leading to a significant decrease in the survival rate. As a result of injuries, significant quantities of free radicals (FR) are produced, responsible for oxidative stress (OS). To minimize the effects of OS, we recommend the administration of antioxidant substances. In this study we want to highlight statistically significant correlations between antioxidant therapy and a series of clinical variables.

METHODS

This retrospective study included 132 polytrauma patients admitted to the ICU-CA between January 2013 and December 2014. The selection criteria were: injury severity score (ISS) ≥ 16, ≥ 18 years, presence of thoracic trauma (abbreviated injury scale, AIS ≥ 3). Eligible patients (n = 82) were divided into two groups: Group 1 (n = 32, antioxidant free, patients from 2013) and Group 2 (n = 50 antioxidant therapy, patients from 2014). Antioxidant therapy consisted in the administration of vitamin C (i.v.), vitamin B1 (i.v.), and N-acetylcysteine (i.v.). Clinical and biological tests were repeated until discharge from ICU-CA or death.

RESULTS

Between Group 1 and Group 2 statistically significant differences were highlighted regarding the ISS score (p = 0.0030). 66% of patients from Group 2 were admitted at more than 24 hours after the trauma, in contrast to the patients from Group 1, where 62.5% were directly admitted to the ICU (p = 0.0114). Compared with the patients from Group 1, patients who received antioxidant therapy show improved parameters: leukocytes (p < 0.0001), platelets (p = 0.0489), urea (p = 0.0199), total bilirubin (p = 0.0111), alanine transaminase (p = 0.0010), lactat dehydrogenase (p < 0.0001). Between the two groups there were no statistically significant differences regarding the length of stay in the ICU-CA (p = 0.4697) and mortality (p = 0.1865).

CONCLUSIONS

Following the study, we can affirm that due to the administration of antioxidant substances, posttraumatic complications are greatly reduced. Moreover, the administration of high dose of antioxidants remarkably improves the clinical status of the critical patient.

A study on correlation of pedestrian head injuries with physical parameters using in-depth traffic accident data and mathematical models

The objective of the present study is to predict brain injuries and injury severities from realworld traffic accidents via in-depth investigation of head impact responses, injuries and brain injury tolerances. Firstly, a total of 43 passenger car versus adult pedestrian accidents were selected from two databases of the In-depth Investigation of Vehicle Accidents in Changsha of China (IVAC) and the German In-Depth Accident Study (GIDAS). In a previous study the 43 accidents were reconstructed by using the multi-body system (MBS) model (Peng et al., 2013a) for determining the initial conditions of the head-windscreen impact in each accident. Then, a study of the head injuries and injury mechanisms is carried out via 43 finite element (FE) modelings of a head strike to a windscreen, in which the boundary and loading conditions are defined according to results from accident reconstructions, including impact velocity, position and orientation of the head FE model. The brain dynamic responses were calculated for the physical parameters of the coup/countercoup pressure, von Mises and maximum shear stresses at the cerebrum, the callosum, the cerebellum and the brain stem. In addition, head injury criteria, including the cumulative strain damage measure (CSDM) (with tissue level strain threshold 0.20) and the dilatational damage measure (DDM), were developed in order to predict the diffuse axonal injury (DAI) and contusions, respectively. The correlations between calculated parameters and brain injuries were determined via comparing the simulation results with the observed injuries in accident data. The regression models were developed for predicting the injury risks in terms of the brain dynamic responses and the calculated CSDM and DDM values. The results indicate that the predicted values of 50% probability causing head injuries in the Abbreviated Injury Scale (AIS) 2+ correspond to coup pressure 167 kPa, countercoup pressure -117 kPa, von Mises 16.3 kPa and shear stress 7.9 kPa respectively, and causing AIS 3+ head injuries were 227 kPa, -169 kPa, 24.2 kPa and 12.2 kPa respectively. The results also suggest that a 50% probability of contusions corresponds to CSDM value of 48% at strain levels of 0.2, and the 50% probability of contusions corresponds to a DDM value of 6.7%.

Comparing motor-vehicle crash risk of EU and US vehicles

OBJECTIVE

This study examined the hypotheses that passenger vehicles meeting European Union (EU) safety standards have similar crashworthiness to United States (US) -regulated vehicles in the US driving environment, and vice versa.

METHODS

The first step involved identifying appropriate databases of US and EU crashes that include in-depth crash information, such as estimation of crash severity using Delta-V and injury outcome based on medical records. The next step was to harmonize variable definitions and sampling criteria so that the EU data could be combined and compared to the US data using the same or equivalent parameters. Logistic regression models of the risk of a Maximum injury according to the Abbreviated Injury Scale of 3 or greater, or fatality (MAIS3+F) in EU-regulated and US-regulated vehicles were constructed. The injury risk predictions of the EU model and the US model were each applied to both the US and EU standard crash populations. Frontal, near-side, and far-side crashes were analyzed together (termed "front/side crashes") and a separate model was developed for rollover crashes.

RESULTS

For the front/side model applied to the US standard population, the mean estimated risk for the US-vehicle model is 0.035 (sd = 0.012), and the mean estimated risk for the EU-vehicle model is 0.023 (sd = 0.016). When applied to the EU front/side population, the US model predicted a 0.065 risk (sd = 0.027), and the EU model predicted a 0.052 risk (sd = 0.025). For the rollover model applied to the US standard population, the US model predicted a risk of 0.071 (sd = 0.024), and the EU model predicted 0.128 risk (sd = 0.057). When applied to the EU rollover standard population, the US model predicted a 0.067 risk (sd = 0.024), and the EU model predicted 0.103 risk (sd = 0.040).

CONCLUSIONS

The results based on these methods indicate that EU vehicles most likely have a lower risk of MAIS3+F injury in front/side impacts, while US vehicles most likely have a lower risk of MAIS3+F injury in llroovers. These results should be interpreted with an understanding of the uncertainty of the estimates, the study limitations, and our recommendations for further study detailed in the report.

Pattern and spectrum of tornado injury and its geographical information system distribution in Yancheng, China: a cross-sectional study

OBJECTIVES

Few studies of tornado injuries have considered differences related to damage levels and Enhanced-Fujita (EF) scale ratings. This study aimed to evaluate the pattern, spectrum and geographical distribution of injuries related to the Yancheng tornado and provide guidelines for effective emergency medical strategies.

SETTING

The study was conducted at three hospitals which treated patients with injuries related to the tornado in Yancheng, China.

PARTICIPANTS

We obtained the records of 451 patients with tornado-related injuries. Of these, 401 valid trauma medical records were included; 50 other records were excluded for insufficient information. Informed consent was obtained from all patients by telephone.

MAIN OUTCOME MEASURES

We analysed patients' injury sites and types and used the abbreviated injury scale (AIS) to standardise injury severity. Geographical information system and non-parametric tests were used to analyse the effects of geographical factors on casualties.

RESULTS

Women, middle-aged/elderly individuals (age>45 years) and children/adolescents (<18 years) accounted for 51.62%, 77.30% and 12.47% of injured patients, respectively. This caused a dumbbell-shaped age distribution. Head (46.63%), body surface (39.90%) and lower-limb (29.43%) injuries were common, as were soft-tissue injuries (90.77%), fractures (38.90%) and organ damage (19.70%). Minor injuries (AIS=1) were common (60.85%), whereas critical/fatal injuries (AIS≥5) were very rare (2.50%). Although the densities of injury varied among damage levels and EF ratings for different areas, area-wise differences in injury severity (AIS scores) were not significant (p>0.05).

CONCLUSION

We recommend the use of helmets to prevent head injuries caused by tornadoes and suggest prioritising the treatment of high-risk head and multiple-organ injuries. Additionally, medical rescuers should follow the 'same quality and different quantity' principle: the injured in all affected areas should receive equal attention, but numbers of medical personnel should be allocated based on the level of effects from the tornado.

Association of Early Myocardial Workload and Mortality Following Severe Traumatic Brain Injury

OBJECTIVES

To examine the impact of early myocardial workload on in-hospital mortality following isolated severe traumatic brain injury.

DESIGN

Retrospective cohort study.

SETTING

Data from the National Trauma Databank, a multicenter trauma registry operated by the American College of Surgeons, from 2007 to 2014.

PATIENTS

Adult patients with isolated severe traumatic brain injury (defined as admission Glasgow Coma Scale < 8 and head Abbreviated Injury Score ≥ 4).

INTERVENTIONS

Admission rate-pressure product, categorized into five levels based on published low, normal, and submaximal human thresholds: less than 5,000; 5,000-9,999; 10,000-14,999; 15,000-19,999; and greater than 20,000.

MEASUREMENTS AND MAIN RESULTS

Data from 26,412 patients were analyzed. Most patients had a normal rate-pressure product (43%), 35% had elevated rate-pressure product, and 22% had depressed rate-pressure product at hospital admission. Compared with the normal rate-pressure product group, in-hospital mortality was 22 percentage points higher in the lowest rate-pressure product group (cumulative mortality, 50.2%; 95% CI, 43.6-56.9%) and 11 percentage points higher in the highest rate-pressure product group (cumulative mortality, 39.2%; 95% CI, 37.4-40.9%). The lowest rate-pressure product group was associated with a 50% increased risk of mortality, compared with the normal rate-pressure product group (adjusted relative risk, 1.50; 95% CI, 1.31-1.76%; p < 0.0001), and the highest rate-pressure product group was associated with a 25% increased risk of mortality, compared with the normal rate-pressure product group (adjusted relative risk, 1.25; 95% CI, 1.18-1.92%; p < 0.0001). This relationship was blunted with increasing age. Among patients with normotension, those with depressed and elevated rate-pressure products experienced increased mortality.

CONCLUSIONS

Adults with severe traumatic brain injury experience heterogeneous myocardial workload profiles that have a "U-shaped" relationship with mortality, even in the presence of a normal blood pressure. Our findings are novel and suggest that cardiac performance is important following severe traumatic brain injury.

Have pedestrian subsystem tests improved passenger car front shape?

Subsystem impactor tests are the main approaches for evaluation of safety performance of vehicle front design for pedestrian protection in legislative regulations. However, the main aspects of vehicle safety for pedestrians are shape and stiffness, and though it is clear that subsystem impact tests encourage lower vehicle front stiffness, it is unclear whether they promote improved vehicle front shapes for pedestrian protection. The purpose of this paper is therefore to investigate the effects of European pedestrian safety regulations on passenger car front shape and pedestrian injury risk using recent German In-Depth Accident Study (GIDAS) pedestrian collision data and numerical simulations. Firstly, a sample of 579 pedestrian collision cases involving 190 different car models between 2000-2015 extracted from the GIDAS was used to compare front-end shapes of passenger cars manufactured before and after the legislative pedestrian safety regulations were introduced in Europe. The focus was on changes in passenger car front shape and differences in pedestrian AIS2+ (Abbreviated Injury Scale at least level 2) leg, pelvis/femur and head injury risk observed in collisions. Multi-body simulations were also used to assess changes in vehicle aggressivity due to the observed changes in vehicle shape. The results show that newer passenger cars tend to have a flatter and wider bumper, higher bonnet leading edge, shorter and steeper bonnet and a shallower windscreen. Both the collision data and the numerical simulations indicate that newer passenger car front bumper designs are significantly safer for pedestrians' legs. However, the results also show that the higher bonnet leading edge in newer passenger cars is poor for pedestrian pelvis/femur protection, even though newer cars show an obviously lower AIS2+ injury risk to younger pedestrians in collisions. Newer cars have a lower AIS2+ head injury risk for pedestrians in collisions, but the numerical analysis indicate that this is not likely due to shape changes in passenger car fronts. Overall, the introduction of pedestrian safety regulations has resulted in reductions in pedestrian injury risk, but further benefits would accrue from tests which promote a lower bonnet leading edge. The influence of vehicle shape on pedestrian head injury risk remains unclear.

The effect of correct cross-chest clip use on injury outcomes in young children during motor vehicle crashes

OBJECTIVE

Traffic crashes have high mortality and morbidity for young children. Though many specialized child restraint systems improve injury outcomes, no large-scale studies have investigated the cross-chest clip's role during a crash, despite concerns in some jurisdictions about the potential for neck contact injuries from the clips. This study aimed to investigate the relationship between cross-chest clip use and injury outcomes in children between 0 and 4 years of age.

METHODS

Child passengers between 0 and 4 years of age were selected from the NASS-CDS data sets (2003-2014). Multiple regression analysis was used to model injury outcomes while controlling for age, crash severity, crash direction, and restraint type. The primary outcomes were overall Abbreviated Injury Score (AIS) 2+ injury, and the presence of any neck injury.

RESULTS

Across all children aged 0-4 years, correct chest clip use was associated with decreased Abbreviated Injury Scale (AIS) 2+ injury (odds ratio [OR] = 0.44, 95% confidence interval [CI], 0.21-0.91) and was not associated with neck injury. However, outcomes varied by age. In children <12 months old, chest clip use was associated with decreased AIS 2+ injury (OR = 0.09, 95% CI, 0.02-0.44). Neck injury (n = 7, all AIS 1) for this age group only occurred with correct cross-chest clip use. For 1- to 4-year-old children, cross-chest clip use had no association with AIS 2+ injury, and correct use significantly decreased the odds of neck injury (OR = 0.49; 95% CI, 0.27-0.87) compared to an incorrectly used or absent cross-chest clip. No serious injuries were directly caused by the chest clips.

CONCLUSIONS

Correct cross-chest clip use appeared to reduce injury in crashes, and there was no evidence of serious clip-induced injury in children in 5-point harness restraints.

Driver injury in near- and far-side impacts: Update on the effect of front passenger belt use

PURPOSE

This is a study that updates earlier research on the influence of a front passenger on the risk for severe driver injury in near-side and far-side impacts. It includes the effects of belt use by the driver and passenger, identifies body regions involved in driver injury, and identifies the sources for severe driver head injury.

METHODS

1997-2015 NASS-CDS data were used to investigate the risk for Maximum Abbreviated Injury Scale (MAIS) 4 + F driver injury in near-side and far-side impacts by front passenger belt use and as a sole occupant in the driver seat. Side impacts were identified with GAD1 = L or R without rollover (rollover ≤ 0). Front-outboard occupants were included without ejection (ejection = 0). Injury severity was defined by MAIS and fatality (F) by TREATMNT = 1 or INJSEV = 4. Weighted data were determined. The risk for MAIS 4 + F was determined using the number of occupants with known injury status MAIS 0 + F. Standard errors were determined.

RESULTS

Overall, belted drivers had greater risks for severe injury in near-side than far-side impacts. As a sole driver, the risk was 0.969 ± 0.212% for near-side and 0.313 ± 0.069% for far-side impacts (P < .005). The driver's risk was 0.933 ± 0.430% with an unbelted passenger and 0.596 ± 0.144% with a belted passenger in near-side impacts. The risk was 2.17 times greater with an unbelted passenger (NS). The driver's risk was 0.782 ± 0.431% with an unbelted passenger and 0.361% ± 0.114% with a belted passenger in far-side impacts. The risk was 1.57 times greater with an unbelted passenger (P < .10). Seat belt use was 66 to 95% effective in preventing MAIS 4 + F injury in the driver. For belted drivers, the head and thorax were the leading body regions for Abbreviated Injury Scale (AIS) 4+ injury. For near-side impacts, the leading sources for AIS 4+ head injury were the left B-pillar, roof, and other vehicle. For far-side impacts, the leading sources were the other occupant, right interior, and roof (8.5%).

CONCLUSIONS

Seat belt use by a passenger lowered the risk of severe driver injury in side impacts. The reduction was 54% in near-side impacts and 36% in far-side impacts. Belted drivers experienced mostly head and thoracic AIS 4+ injuries. Head injuries in the belted drivers were from contact with the side interior and the other occupant, even with a belted passenger.

Functional outcomes of motor vehicle crash thoracic injuries in pediatric and adult occupants

OBJECTIVE

Characterization of the severity of injury should account for both mortality and disability. The objective of this study was to develop a disability metric for thoracic injuries in motor vehicle crashes (MVCs) and compare the functional outcomes between the pediatric and adult populations.

METHODS

Disability risk (DR) was quantified using Functional Independence Measure (FIM) scores within the National Trauma Data Bank for the most frequently occurring Abbreviated Injury Scale (AIS) 2-5 thoracic injuries. Occupants with thoracic injury were classified as disabled or not disabled based on the FIM scale, and comparisons were made between the following age groups: pediatric, adult, middle-aged, and older occupants (ages 7-18, 19-45, 46-65, and 66+, respectively). For each age group, DR was calculated by dividing the number of patients who were disabled and sustained a given injury by the number of patients who sustained a given injury. To account for the effect of higher severity co-injuries, a maximum AIS adjusted DR (DR_MAIS) was also calculated for each injury. DR and DR_MAIS could range from 0 to 100% disability risk.

RESULTS

The mean DR_MAIS for MVC thoracic injuries was 20% for pediatric occupants, 22% for adults, 29% for middle-aged adults, and 43% for older adults. Older adults possessed higher DR_MAIS values for diaphragm laceration/rupture, heart laceration, hemo/pneumothorax, lung contusion/laceration, and rib and sternum fracture compared to the other age groups. The pediatric population possessed a higher DR_MAIS value for flail chest compared to the other age groups.

CONCLUSION

Older adults had significantly greater overall disability than each of the other age groups for thoracic injuries. The developed disability metrics are important in quantifying the significant burden of injuries and loss of quality life years. Such metrics can be used to better characterize severity of injury and further the understanding of age-related differences in injury outcomes, which can influence future age-specific modifications to AIS.

Characterization of the occult nature of frequently occurring pediatric motor vehicle crash injuries

BACKGROUND

Occult injuries are those likely to be missed on initial assessment by first responders and, though initially asymptomatic, they may present suddenly and lead to rapid patient decompensation. No scoring systems to quantify the occultness of pediatric injuries have been established. Such a scoring system will be useful in the creation of an Advanced Automotive Crash Notification (AACN) system that assists first responders in making triage decisions following a motor vehicle crash (MVC).

STUDY DESIGN

The most frequent MVC injuries were determined for 0-4, 5-9, 10-14 and 15-18 year olds. For each age-specific injury, experts with pediatric trauma expertise were asked to rate the likelihood that the injury may be missed by first responders. An occult score (ranging from 0-1) was calculated by averaging and normalizing the responses of the experts polled.

RESULTS

Evaluation of all injuries across all age groups demonstrated greater occult scores for the younger age groups compared to older age groups (mean occult score 0-4yo: 0.61 ± 0.23, 5-9yo: 0.53 ± 0.25, 10-14yo: 0.48 ± 0.23, and 15-18yo: 0.42 ± 0.22, p < 0.01). Body-region specific occult scores revealed that experts judged abdominal, spine and thoracic injuries to be more occult than injuries to other body regions.

CONCLUSIONS

The occult scores suggested that injuries are more difficult to detect in younger age groups, likely given their inability to express symptoms. An AACN algorithm that can predict the presence of clinically undetectable injuries at the scene can improve triage of children with these injuries to higher levels of care.

Quality of head injury coding from autopsy reports with AIS © 2005 update 2008

ABSTACT Objective: Coding injuries from autopsy reports of traffic accident victims according to Abbreviated Injury Scale AIS © 2005 update 2008 [1] is quite time consuming. The suspicion arose, that many issues leading to discussion between coder and control reader were based on information required by the AIS that was not documented in the autopsy reports.

METHODS

To quantify this suspicion, we introduced an AIS-detail-indicator (AIS-DI). To each injury in the AIS Codebook one letter from A to N was assigned indicating the level of detail. Rules were formulated to receive repeatable assignments. This scheme was applied to a selection of 149 multiply injured traffic fatalities. The frequencies of "not A" codes were calculated for each body region and it was analysed, why the most detailed level A had not been coded. As a first finding, the results of the head region are presented.

RESULTS

747 AIS head injury codes were found in 137 traffic fatalities, and 60% of these injuries were coded with an AIS-DI of level A. There are three different explanations for codes of AIS-DI "not A": Group 1 "Missing information in autopsy report" (5%), Group 2 "Clinical data required by AIS" (20%), and Group 3 "AIS system determined" (15%). Groups 1 and 2 show consequences for the ISS in 25 cases. Other body regions might perform differently.

CONCLUSIONS

The AIS-DI can indicate the quality of the underlying data basis and, depending on the aims of different AIS users it can be a helpful tool for quality checks.

Injury analysis of patients according to impact patterns involved in pedestrian traffic crashes

OBJECTIVES

In cases of car-to-person pedestrian traffic crashes (PTCs), the principal issue is determining at what point the car collided with the pedestrian. Accordingly, the objective of the present study was to use the medical records of patients injured in PTCs to investigate the characteristics of crash types and the areas and injury severity and to determine whether there are differences in injuries due to the angle, motion, and position at the point of impact.

METHODS

The present study examined 231 PTC patients admitted to the emergency room (ER) between January and December 2014. Electronic medical records from the hospital were used to divide the patient data according to Abbreviated Injury Scale (AIS) codes for injured areas based on sex, age, time of the crash, outcomes after ER treatment, and major symptoms. Among 231 patients, police reports on 67 crash cases, involving 70 people, were obtained with the help of local police departments, and these reports were used to reconstruct details of the actual crash. For statistical analysis, a chi-square test and a one-way analysis of variance calculation were used to compare the Injury Severity Score (ISS) based on groups and stages, with a statistical significance level set to P < .05.

RESULTS

With respect to patients who were admitted for PTC, 52.4% were females and 47.6% were males. The frequency of crashes was high in middle-aged and elderly groups, as well as for youths between 10 and 19 years old. With respect to outcomes after ER treatment, discharge to home after symptom improvement was the most common outcome (24.6%). Admissions to the intensive care unit (25.1%) and to the general ward (23.8%) were also high. In terms of major symptoms, the most common injuries were to the head, resulting from a rotatory motion post impact (35.9%), and injuries to the legs, resulting from the impact of a direct collision with an object (25.1%).

CONCLUSIONS

This study demonstrated that injuries to the chest and abdomen were the most severe in the fender vault group and head and neck injuries were the most severe in the roof vault group. In particular, the Injury Severity Score was highest in the roof vault group.

AIS scores in spine and spinal cord trauma: Epidemiological considerations

BACKGROUND

The Abbreviated Injury Scale (AIS) is an internationally accepted coding system created by the Association for the Advancement of Automotive Medicine, utilized to code traumatic injuries as a function of severity, the latter often defined as mortality risk. Periodic reassessment of that risk is prudent, in light of advances in health care and relationship of nonanatomic factors to death.

OBJECTIVE

The objective of this study was to reevaluate the risk of death associated with spine fractures with and without neurologic deficit, age factors associated with it, and the impact of hospital coding on the accuracy of these efforts.

METHODS

Medical records and imaging of patients treated at a level 1 trauma center from 2014 through 2016 with discharge International Classification of Diseases, 10th revision (ICD-10) diagnoses of spinal trauma and spinal cord injury (SCI) were reviewed. Data were collected on demographics, complications, neurologic status, and outcomes.

RESULTS

Three hundred seventy patients met the criteria for inclusion in this effort. Errors in ICD-10 discharge codes were seen in 45% of the cases, both false positive and negative. One hundred thirty-four patients, with a mean age of 45, were admitted with neurologic deficit. There were 8 SCI-related deaths; 2 were postoperative out of 110 undergoing surgical treatment. All deaths in this group were in patients with upper level SCI, with a mean age of 68. Ten patients had spontaneous neurologic improvement within 24 h. One hundred nineteen patients without deficit had AIS 2 scored fractures; there was one postoperative death out of 47 patients undergoing surgical treatment. One hundred seventeen patients without deficit suffered AIS 3 fractures; 66 underwent surgery without any deaths. There was one nonoperative death. Age and high quadriplegia were the only factors associated with mortality.

CONCLUSIONS

Mortality risk in patients with deficit was associated more with age at injury than extent of anatomic injury. Spine trauma without neurologic deficit is benign in younger populations and AIS scores could be age adjusted. Mortality risk is higher in high cervical injuries with neurologic deficit and in the elderly. An incidental finding is that demographic studies based solely on discharge ICD coding may contain errors and should be considered critically.

Active muscle response contributes to increased injury risk of lower extremity in occupant-knee airbag interaction

OBJECTIVE

Recent field data analysis has demonstrated that knee airbags (KABs) can reduce occupant femur and pelvis injuries but may be insufficient to decrease leg injuries in motor vehicle crashes. An enhanced understanding of the associated injury mechanisms requires accurate assessment of physiological-based occupant parameters, some of which are difficult or impossible to obtain from experiments. This study sought to explore how active muscle response can influence the injury risk of lower extremities during KAB deployment using computational biomechanical analysis.

METHODS

A full-factorial matrix, consisting of 48 finite element simulations of a 50th percentile occupant human model in a simplified vehicle interior, was designed. The matrix included 32 new cases in combination with 16 previously reported cases. The following influencing factors were taken into account: muscle activation, KAB use, KAB design, pre-impact seating position, and crash mode. Responses of 32 lower extremity muscles during emergency braking were replicated using one-dimensional elements of a Hill-type constitutive model, with the activation level determined from inverse dynamics and validated by existing volunteer tests. Dynamics of unfolding and inflating of the KABs were represented using the state-of-the-art corpuscular particle method. Abbreviated Injury Scale (AIS) 2+ injury risks of the knee-thigh-hip (KTH) complex and the tibia were assessed using axial force and resultant bending moments. With all simulation cases being taken together, a general linear model was used to assess factor significance (P <.05).

RESULTS

As estimated by the regression model across all simulation cases, use of KABs significantly reduced axial femur forces by 4.74 ± 0.43 kN and AIS 2+ injury risk of KTH by 47 ± 6% (P <.05) but did not provide substantial change to injury risk of leg fractures. Muscle activation significantly increased axial force and bending moment of the femur (3.87 ± 0.38 kN and 64.3 ± 5.9 Nm), the tibia (1.49 ± 0.12 kN and 43.0 ± 6.4 Nm), and the resultant probability of AIS 2+ tibia injuries by 36 ± 6% regardless of KAB use and crash scenario. Specifically, when counting on a relative scale, muscle activation exhibited more prominent elevation of injury risk for in-position occupants than out-of-position occupants. In a representative crash scenario-that is, using a bottom-deployed KAB in a nearside oblique impact-muscle bracing of the right leg may lead to 2.6 times higher tibia fracture risk than being relaxed for an out-of-position occupant and 5.4 times higher for an in-position occupant.

DISCUSSION AND CONCLUSIONS

The mechanism of higher leg injuries in the presence of KAB deployment in real-world crashes can be interpreted by the increased effective body mass, axial compression along the shafts of long bones, and altered pre-impact posture due to muscle contraction. The present analysis suggests that active muscle response can increase the risk of lower extremity injury during occupant-KAB interaction. This study demonstrated the feasibility of advanced human models to investigate the influence of physiologically based parameters on injury outcomes evidenced in field study and insight from computational examination on human variability for development of future restraint systems. Future efforts are recommended on realistic vehicle and restraint environment and advanced modeling strategies toward a full understanding of KAB efficacy.

Functional outcomes of thoracic injuries in pediatric and adult occupants

OBJECTIVE

To develop a disability metric for motor vehicle crash (MVC) thoracic injuries and compare functional outcomes between pediatric and adult populations.

METHODS

Disability risk (DR) was quantified using Functional Independence Measure (FIM) scores within the National Trauma Data Bank (NTDB) for the top 95% most frequently occurring AIS 2, 3, 4, and 5 thoracic injuries in NASS-CDS 2000-2011. The NTDB contains a truncated form of the FIM score, including three items (self-feed, locomotion, and verbal expression), each graded from full functional dependence to full functional independence. Pediatric (ages 7-18 years), adult (19-45), middle-aged adult (46-65), and older adult (66+) MVC occupants were classified as disabled or not disabled based on the FIM scale. The DR was calculated for each injury within each age group by dividing the number of patients who were disabled that sustained the specific injury by the number of patients who sustained the specific injury. To account for the impact of more severe co-injuries, a maximum Abbreviated Injury Scale (MAIS) adjusted DR (DR_MAIS) was also calculated. DR and DR_MAIS could range from 0 (0% disability risk) to 1 (100% disability risk).

RESULTS

The mean DR_MAIS for MVC thoracic injuries was 20% for pediatric occupants, 22% for adults, 29% for middle-aged adults, and 43% for older adults. Older adults possessed higher DR_MAIS values for diaphragm laceration/rupture, heart laceration, hemo/pneumothorax, lung contusion/laceration, rib fracture, and sternum fracture compared to the other age groups. The pediatric population possessed a higher DR_MAIS value for flail chest compared to the other age groups.

CONCLUSIONS

Older adults had significantly greater overall disability than each of the other age groups for thoracic injuries. The developed disability metrics are important in quantifying the significant burden of injuries and loss of quality life years. Such metrics can be used to better characterize severity of injury and further the understanding of age-related differences in injury outcomes, which can impact future age-specific modifications to AIS.

Differences in the protective capabilities of bicycle helmets in real-world and standard-specified impact scenarios

OBJECTIVE

The purpose of this study was to investigate relative differences in impact attenuation capabilities of bicycle helmets under real-world impact conditions and safety standard-specified conditions using a standard rig.

METHODS

A Consumer Product Safety Commission (CPSC) test rig was used to impact 10 helmet models of varied design. Impact configurations included 2 locations and 2 velocities. A frontal rim location (inferior to the standard-defined test area) and a temporal location were selected to reflect common cyclist impacts. An impact velocity of 3.4 m/s, an average normal impact velocity in cyclist accidents, was selected, as well as the CPSC standard velocity of 6.2 m/s. Four samples per helmet model were subjected to each of the 4 impact configurations once (randomized test order per sample), resulting in 160 drop tests. Peak linear acceleration (PLA) and head injury criterion (HIC)-based Abbreviated Injury Scale (AIS) ≥ 4 brain injury risk were determined and compared across helmets and impact configurations using analysis of variance. Other impact characteristics such as duration, effective liner stiffness, and energy dissipated were also calculated from acceleration data.

RESULTS

Helmet performance varied significantly between models. PLA ranged from 78 to 169 g at 3.4 m/s (0-2% AIS ≥ 4 brain injury risk) and 165-432 g (10-100% risk) at 6.2 m/s. Temporal impacts resulted in higher PLAs than frontal impacts, likely due to increased effective liner stiffness. However, 2 helmets exceeded the CPSC pass-fail threshold (300 g) at the frontal rim location, producing >70% risk. Force-displacement curves suggest that bottoming-out occurred in these impacts. Aside from bottoming-out cases, helmets that performed worse in one impact configuration tended to perform worse in others, with non-road-style helmets among the worst.

CONCLUSIONS

The 10 bicycle helmets tested produced considerable differences in their protective capabilities under both real-world and standard-specified conditions on the CPSC rig. Risk of severe brain injury varied widely between helmets at the standard impact velocity, whereas the common, lower severity impacts produced PLAs associated with concussion. Helmets of a nonroad style generally performed worse across configuration. The temporal location produced higher risks for most helmets, although some helmets were found to offer inadequate protection at the helmet rim. Because this is a commonly impacted location in cyclist accidents, there may be benefit to expanding the testable area in standards to include the rim. Results from this study demonstrate the value in testing nonstandard conditions and can be used to inform standards testing and helmet design.

Numerical investigation of driver lower extremity injuries in finite element frontal crash reconstruction

OBJECTIVE

Lower extremity injuries are the most frequent Abbreviated Injury Scale (AIS) 2 injury for drivers in frontal crashes. The objective was to reconstruct 11 real-world motor vehicle crashes (2 with AIS 2+ distal lower extremity injury and 9 without lower extremity injury) and to analyze the vehicle parameters and driver attributes that affect injury risk.

METHODS

Eleven frontal crashes were reconstructed with a finite element simplified vehicle model (SVM) using a semi-automated optimization method. The SVM was tuned to each corresponding vehicle and the Total HUman Model for Safety (THUMS) Ver 4.01 was scaled and positioned in a baseline configuration to mimic the documented precrash driver posture. The event data recorder crash pulse was applied as the boundary condition for each case. Additionally, for the 2 cases with lower extremity injury, 120 simulations to quantify the uncertainty and response variation were performed varying the following parameters using a Latin hypercube design of experiment (DOE): seat track position, seatback angle, steering column angle, steering column position, and D-ring height. Injury metrics implemented within THUMS were calculated from the femur, tibia, and ankle and cross-compared among the 11 baseline cases using tibia index and multiple injury risk functions. Kinetic and kinematic data from the 120-simulation DOE were analyzed and fit to regression models to examine any causal relationship between occupant positioning and lower extremity injury risk.

RESULTS

Of the 11 real-world crashes, both cases with lower extremity injuries resulted in elevated tibia axial forces and resultant bending moments, compared to the 9 cases without lower extremity injury. The average tibia index of the 2 cases with distal lower extremity injury (left: 1.79; right: 1.19) was higher than that in the 9 cases without lower extremity injury (left: 1.16, P =.024; right: 0.82, P =.024). An increased risk of AIS 2+ tibia shaft (33.6%), distal tibia and hindfoot (20.0%), as well as ankle malleolar (14.5%) fracture was also observed for the injured compared to the noninjured cases. Rearward seat track position, reclined seat back angle, and reduced seat height were correlated with elevated tibia axial force and increased tibia index, imposing additional lower extremity injury risk.

CONCLUSIONS

This study provides a computational framework for assessing lower extremity injuries and elucidates the effect of precrash driver posture on lower extremity injury risk while accounting for vehicle parameters and driver attributes. Results from the study aid in the evaluation of real-world injury data, the understanding of factors contributing to injury risk, and the prevention of lower extremity injuries.

Belted driver fatalities: Time of death and risk by injury severity

PURPOSE

This is a descriptive study of the fatality risk by injury severity and time of death for lap-shoulder-belted drivers without ejection in modern vehicles. It also determined the body region for severe injuries experienced by belted drivers using the most recent federal crash data.

METHODS

1997-2015 NASS-CDS data were evaluated for fatally injured lap-shoulder-belted drivers without ejection in light vehicles of 1997+ model year (MY). The severity of injuries sustained by belted drivers was assessed by the Maximum Abbreviated Injury Scale (MAIS) and individual injuries by Abbreviated Injury Scale (AIS) and body region. The change in fatality risk with MAIS was fit with a Logist function. Time of death was determined using the variable DEATH, which is reported hourly in unequal intervals up to 24 h and then daily up to 30 days after the crash. The fraction (f) and cumulative fraction (F) of the deaths are reported for each time period up to 30 days. A power or logarithmic curve was fit to the data using the trendline functions in Excel.

RESULTS

The NASS-CDS sample included 20,610,000 belted drivers with 37,974 fatalities from 1997 to 2015. The fraction of driver deaths increased with maximum injury severity (MAIS). For example, 17.4% of drivers died within 30 days with MAIS 4 injury. Virtually all drivers (99.7%) died with MAIS 6 injury. The change in fatality risk with injury severity was r = [1 + exp^{(10.159 - 2.088MAIS)}]^-1, R² = 0.950. Overall, there were 19,772 driver deaths with MAIS 4-6 injury and 13,059 with MAIS 0-3 injury. In addition, 44.7% of driver deaths occurred within 1.5 h of the crash, 56.7% within 2.5 h, and 64.6% within 4.5 h after the crash. The cumulative fraction of the deaths (F) up to 30 days was fit with a logarithmic function. It was F = 0.0739ln(t) + 0.5302, R² = 0.976, for deaths after 3.5 h. There were 19,772 driver deaths with 52,130 AIS 4+ injuries. On average, the driver experienced 2.64 AIS 4+ injuries most commonly to the head (44.5%) and thorax (38.1%).

CONCLUSIONS

The risk for belted driver deaths exponentially increased with MAIS. A majority of deaths occurred within 2.5 h of the crash. On average, fatally injured drivers experienced 2.64 AIS 4+ injuries, primarily to the head and thorax.

Deep coma does not always predict poor outcomes among patients with polytrauma

PURPOSES

This study aimed to clarify the prognosis of polytrauma patients presenting to the emergency department (ED) with a Glasgow Coma Scale score (GCS) of 3.

METHODS

A trauma registry system has been established at our institution since 2009. The current study reviewed patients in the registry who presented to the ED with a GCS of 3 from January 2011 to December 2015. Surviving and non-surviving patients were compared to identify the prognostic factors of patient survival. The study also aimed to determine the factors contributing to patients who survived with a GCS > 13 at discharge.

RESULTS

During the study period, 145 patients were enrolled in the study, 119 of whom (82.1%) did not survive the traumatic insult. Of the 26 survivors, 13 (9.0%) had a GCS of 14 or 15 at discharge. The multiple logistic regression revealed that a lack of bilateral dilated and fixed pupils (BFDP) (OR 5.967, 95% CI 1.780-19.997, p = 0.004) and a GCS > 3 after resuscitation (OR 6.875, 95% CI 2.135-22.138, p = 0.001) were independent prognostic factors of survival. Based on the multiple logistic regression, an age under 40 years (OR 16.405, 95% CI 1.520-177.066, p = 0.021) and a GCS > 3 after resuscitation (OR 12.100, 95% CI 1.058-138.352, p = 0.045) were independent prognostic factors of a GCS > 13 at discharge.

CONCLUSION

Aggressive resuscitation still provided benefit to polytrauma patients presenting with a GCS of 3, especially those with a rapid response to the resuscitation. Young patients with a deep coma on arrival had a higher probability of functional recovery after resuscitation in the ED.

Classification of the severe trauma patient with the Abbreviated Injury Scale: degree of correlation between versions 98 and 2005 (2008 update)

OBJECTIVES

To explore differences in severity classifications according to 2 versions of the Abbreviated Injury Scale (AIS): version 2005 (the 2008 update) and the earlier version 98. To determine whether possible differences might have an impact on identifying severe trauma patients.

MATERIAL AND METHODS

Descriptive study and cross-sectional analysis of a case series of patients admitted to two spanish hospitals with out-of-hospital injuries between February 2012 and February 2013. For each patient we calculated the Injury Severity Score (ISS), the New Injury Severity Score (NISS), and the AIS scores according to versions 98 and 2005.

RESULTS

The sample included 699 cases. The mean Severity (SD) age of patients was 52.7 (29.2) years, and 388 (55.5%) were males. Version 98 of the AIS correlated more strongly with both the ISS (2.6%) and the NISS (2.9%).

CONCLUSION

The 2008 update of the AIS (version 2005) classified fewer trauma patients than version 98 at the severity levels indicated by the ISS and NISS.

Analysis of injury mechanism of the elderly and non-elderly groups in minor motor vehicle accidents

OBJECTIVE

The purpose of this study is to investigate the injury patterns of noncatastrophic accidents by individual age groups.

METHODS

Data were collected from the Korean In-Depth Accident Study database based on actual accident investigation. The noncatastrophic criteria were classified according to U.S. experts from the Centers for Disease Control and Prevention's recommendations for field triage guidelines of high-risk automobile crash criteria by vehicle intrusions more than 12 in. on occupant sites (including the roof) and more than 18 in. on any site. The Abbreviated Injury Scale (AIS) was used to determine injury patterns for each body region. Severely injured patients were classified as Maximum Abbreviated Injury Scale (MAIS) 3 or higher.

RESULTS

In this study, the most significant injury regions were the head and neck, extremities, and thorax. In addition, the incidence of severe injury among elderly patients was nearly 1.6 times higher than that of non-elderly patients. According to age group, injured body regions among the elderly were the thorax, head and neck, and extremities, in that order. For the non-elderly groups, these were head and neck, extremities, and thorax. Severe injury rates were slightly different for the elderly group (head and neck, abdomen) and non-elderly group (thorax, head and neck).

CONCLUSIONS

In both age groups, the rate of severe injury is proportional to an increase in crush extent zone. Front airbag deployment may have a relatively significant relationship to severe injuries.

Identifying MAIS 3+ injury severity collisions in UK police collision records

OBJECTIVE

This study represents the first stage of a project to identify serious injury, at the level of Maximum Abbreviated Injury Scale (MAIS) 3 + (excluding fatal collisions) from within the police collision data. The resulting data will then be used to identify the vehicle drivers concerned and in later studies these will be culpability scored and profiled to allow targeting of interventions.

METHOD

UK police collision data known as STATS19 for the county of Cambridgeshire were linked using Stata with Trauma Audit and Research Network (TARN) hospital trauma patient data for the same geographical area for the period April 2012 to March 2017. Linking was 2-stage: A deterministic process followed by a probabilistic process.

RESULTS

The linked records represent an individual trauma patient from TARN data linked to an individual trauma casualty from STATS19 data. Full collision data for the incident resulting in the trauma casualty were extracted. The resulting subset of collisions has the MAIS 3+ injury criteria applied. From the 10,498 recorded collisions, the deterministic linking process was successful in linking 257 MAIS 3+ trauma patients to collision injury subjects from 232 separate collisions with the probabilistic process linking a further 22 MAIS 3+ subjects from 21 collision events. The combined collision data for the 253 collisions involved 434 motor vehicle drivers.

CONCLUSIONS

We produced viable results from the available data to identify MAIS 3+ collisions from the overall collision data.

Ten-year review of BMW Accident Research Program-investigated cases

OBJECTIVE

Over the past 10 years, the BMW Accident Research Program (ARP) has investigated how and why occupants are injured in motor vehicle crashes by reconstructing the crash. This research discusses the 2006-2017 ARP case study methodology and comprehensively describes the cases investigated over the past decade.

METHODS

Accident research program cases are selected according to emerging trends and issues identified by BMW. Driver interviews, inspection approvals, police reports, and medical records are obtained. ARP case investigations involve a multidisciplinary team of engineers, automobile crash experts, and a trauma team. For each case, the team reconstructs the crash and explores in detail the crash characteristics, injury outcomes, as well as case significance and countermeasures that could have prevented the crash or mitigated the severity of the crash or injuries sustained.

RESULTS

The ARP investigated 476 BMW-involved crashes between 2006 and 2017 in the United States. The majority of the crash investigations involved a frontal crash (55%). The other crash types included rollover (17%), nearside (13%), farside (9%), and rear crashes (5%). Crash characteristics such as roadway departure (26%), fatality (8%), elderly (>65 years old) occupant crashes (7%), crashes preceded by a medical event (4%), and crashes preceded by the driver falling asleep at the wheel (4%) are particularly informative in regards to advanced driver assistance systems (ADAS) role. The distribution of Maximum Abbreviated Injury Scale (MAIS) scores for the occupants were AIS 1 (23%), AIS 2 (33%), AIS 3 (10%), AIS 4 (4%), and AIS 5 + (7%); 16% of crashes involved uninjured occupants and 7% included no injury information.

CONCLUSIONS

In-depth case reviews of moderate and severe crashes remain vital to determine emerging trends, patterns of crash injury, and analysis of driver assistance systems and other factors with potential to prevent the crash or limit severity.