Characteristics of crashes involving injured children in side impacts

The objective of this study was to define the crash characteristics of near-side impact crashes in which children seated in the rear rows are injured. The crash characteristics included the direction of force, heading angle, horizontal impact location, vertical impact location, extent of deformation and intrusion at the child occupant's seating position. Cases from in-depth crash investigation databases of the NASS-CDS (National Automotive Sampling System-Crashworthiness Data System), CIREN (Crash Injury Research and Engineering Network) and Chalmers University of Technology were reviewed. The principal direction of force was most frequently between 60° and 75°. The heading angle of the bullet vehicle was most commonly between 61° and 90°. The bullet vehicle hit the passenger compartment of the target vehicle, particularly the rear door. Often, one or both of the adjacent pillars to the rear door were involved, most commonly the B pillar. In 11 of 16 crashes, the car sill was not engaged. Most commonly, the deformation extent was into Zone 3 or more – about 40 cm – and the intrusion at the child's seating position was in the range 20–30 cm. This review of the crashes revealed differences between the current side impact test procedures and the actual side impact crashes in which children were injured

Effect of mattress deflection on CPR quality assessment for older children and adolescents

Appropriate chest compression (CC) depth is associated with improved CPR outcome. CCs provided in hospital are often conducted on a compliant mattress. The objective was to quantify the effect of mattress compression on the assessment of CPR quality in children. Methods: A force and deflection sensor (FDS) was used during CPR in the Pediatric Intensive Care Unit and Emergency Department of a children's hospital. The sensor was interposed between the chest of the patient and hands of the rescuer and measured CC depth. Following CPR event, each event was reconstructed with a manikin and an identical mattress/backboard/patient configuration. CCs were performed using FDS on the sternum and a reference accelerometer attached to the spine of the manikin, providing a means to Calculate the mattress deflection. Results: Twelve CPR events with 14,487 CC (11 patients, median age 14.9 years) were recorded and reconstructed: 9 on ICU beds (9296 CC), 3 on stretchers (5191 CC). Measured mean CC depth during CPR was 47 +/- 8 mm on ICU beds, and 45 +/- 7 mm on stretcher beds with overestimation of 13 +/- 4 mm and 4 +/- 1 mm, respectively, due to mattress compression. After adjusting for this, the proportion of CC that met the CPR guidelines decreased from 88.4 to 31.8% on ICU beds (p < 0.001), and 86.3 to 64.7% on stretcher (p < 0.001 The proportion of appropriate depth CC was significantly smaller on ICU beds (p < 0.001). Conclusion: CC conducted on a non-rigid surface may not be deep enough. FDS may overestimate CC depth by 28% on ICU beds, and 10% on stretcher beds

REAR SEAT SAFETY IN FRONTAL TO SIDE IMPACTS – FOCUSING ON OCCUPANTS FROM 3YRS TO SMALL ADULTS

ABSTRACT This study presents a broad comprehensive research effort that combines expertise from industry and academia and uses various methodologies with applied research directed towards countermeasures. The project includes real world crash data analysis, real world driving studies and crash testing and simulations, aiming at enhancing the safety of forward facing child occupants (aged 3y to small adults) in the rear seat during frontal to side impacts. The real world crash data analyses of properly restrained children originate from European as well as US data. Frontal and side impact crash tests are analyzed using different sizes of crash test dummies in different sitting postures. Side impact parameter studies using FE-models are run. The sitting posture and behavior of 12 children are monitored while riding in the rear seat. Also, the body kinematics and belt position during actual braking and turning maneuvers are studied for 16 rear seat child occupants and for various child dummies. Real world crash data indicates that several of the injured children in frontal impacts, despite being properly restrained, impacted the vehicle interior structure with their head/face resulting in serious injury. This was attributed to oblique crashes, pre-crash vehicle maneuvers or high crash severity. Crash tests confirm the importance of proper initial belt-fit for best protection. The crash tests also highlight the difficulty in obtaining the real world kinematics and head impact locations using existing crashtest dummies and test procedures. The side impact parameter studies indicate that the vehicle’s occupant protection systems, such as airbags and seat belt pretensioners, play an important role in protecting children as well. The results from the on-road driving studies illustrate the variation of sitting postures during riding in the rear seat giving valuable input to the effects of the restraint systems and to how representative the standardized dummy seating positioning procedures are. The results from the maneuver driving studies illustrate the importance of understanding the kinematics of a child relative to the seat belt in a real world maneuver situation. Real world safety of rear seat occupants, especially children, involves evaluation of protection beyond standard crash testing scenarios in frontal and side impact conditions. This project explores the complete context of rear seat protection in impact situations ranging from front to side and directions in between highlighting the importance of pre-crash posture and behavior. This research project at SAFER (Vehicle and Traffic Safety Centre at Chalmers), where researchers from the industry and universities cooperate with the aim to further improve safety for children (from 3y) to small adults in the rear seat, speeds up the process to safety implementation due to the interaction between academic and industrial researchers

Acute Depression and Anxiety Symptoms following Concussion in an Adolescent Outpatient Population

Introduction: Research has shown that concussed youth are at increased risk of developing psychiatric symptoms as compared to non-concussed youth. Few studies, however, have detailed the presence and severity of acute depression and anxiety symptoms following a concussion in adolescents, specifically. Thus, the current study aims to describe depression and anxiety symptoms in concussed and non-concussed adolescents using validated measures of depression and anxiety. Methods: The current study includes 284 adolescents (114 cases, 170 controls), 13-18 years of age. Cases included concussed patients at the Children’s Hospital of Philadelphia, and controls were recruited from a local, Philadelphia high school. All subjects completed the Patient-Reported Outcomes Measurement Information System (PROMIS) Depression and Anxiety (Pediatric Short Form 8b) measures at their visits. Adjusted risk ratios and 95% confidence intervals (CI) for above-normal limits of PROMIS Depression and Anxiety were calculated for all subjects. Results: When controlling for sex and a medical history of anxiety, there is a 1.49 increased risk of an above-normal PROMIS Anxiety t-score for cases vs. controls (95% CI: 0.97-2.27, p=0.07). Although not significant, when controlling for sex and a medical history of depression, there is a 1.25 increased risk of an above-normal PROMIS Depression t-score for cases vs. controls (95% CI: 0.84-1.84, p=0.27). Discussion: Our results demonstrate that acutely concussed adolescents have an increased risk of above-normal levels of anxiety, but not depressive, symptoms compared to controls. These findings suggest that clinicians should incorporate psychiatric screening into concussion care and treatment for their adolescent patient population

Consensus Head Acceleration Measurement Practices (CHAMP): Origins, methods, transparency and disclosure

The use of head kinematic measurement devices has recently proliferated owing to technology advances that make such measurement more feasible. In parallel, demand to understand the biomechanics of head impacts and injury in sports and the military has increased as the burden of such loading on the brain has received focused attention. As a result, the field has matured to the point of needing methodological guidelines to improve the rigor and consistency of research and reduce the risk of scientific bias. To this end, a diverse group of scientists undertook a comprehensive effort to define current best practices in head kinematic measurement, culminating in a series of manuscripts outlining consensus methodologies and companion summary statements. Summary statements were discussed, revised, and voted upon at the Consensus Head Acceleration Measurement Practices (CHAMP) Conference in March 2022. This manuscript summarizes the motivation and methods of the consensus process and introduces recommended reporting checklists to be used to increase transparency and rigor of future experimental design and publication of work in this field. The checklists provide an accessible means for researchers to apply the best practices summarized in the companion manuscripts when reporting studies utilizing head kinematic measurement in sport and military settings

A characterization of the anisotropic mechanical properties of the brainstem

This research provided insight into the biomechanics of traumatic brain stem injury by characterizing the response of the brainstem to mechanical deformation. The brainstem is a region of the CNS characterized by axonal fibers longitudinally organized in parallel tracts. This distinct structure helps dictate the material response of the brainstem and suggests that this region may respond to mechanical insult as a transversely isotropic structure. The objective of this work was to investigate this assumption through material testing in three mutually perpendicular directions. A custom designed stress relaxation, oscillatory shear testing apparatus (STA) for testing soft biological tissues in simple shear was constructed and validated. The STA was validated by measurements of complex shear moduli of three mixtures of silicone gel with viscoelastic properties similar to soft biological tissue that were tested in both the STA and a commercially available solids rheometer. The STA was used to perform stress relaxation tests on adult porcine brainstem to characterize the mechanical response of the brainstem. These experiments did not confirm our hypothesis of the brainstem\u27s transversely isotropic material response. Specifically, the calculated relaxation moduli did not vary with testing orientation. We hypothesized that due to the presence of significant relaxation in these tissues, the mechanical response of the brainstem is highly loading rate dependent. A series of dynamic oscillating shear tests in three mutually perpendicular directions were performed to further characterize the anisotropic nature of the brainstem at high loading rates. These experiments confirmed our hypothesis that the brainstem may be described as a transversely isotropic material; the complex moduli in the transverse direction were significantly higher than the other two moduli that were indistinguishable from one another. A novel fiber reinforced composite model composed of viscoelastic fibers surrounded by a viscoelastic matrix was developed to analyze the oscillatory shear data. The model predicted that the fibers are stiffer and more viscous than the surrounding matrix, a relationship reinforced by the results of the oscillatory shear tests. The predicted fiber modulus was confirmed by results of oscillatory shear tests on the optic nerve of the guinea pig

A characterization of the anisotropic mechanical properties of the brainstem

This research provided insight into the biomechanics of traumatic brain stem injury by characterizing the response of the brainstem to mechanical deformation. The brainstem is a region of the CNS characterized by axonal fibers longitudinally organized in parallel tracts. This distinct structure helps dictate the material response of the brainstem and suggests that this region may respond to mechanical insult as a transversely isotropic structure. The objective of this work was to investigate this assumption through material testing in three mutually perpendicular directions. A custom designed stress relaxation, oscillatory shear testing apparatus (STA) for testing soft biological tissues in simple shear was constructed and validated. The STA was validated by measurements of complex shear moduli of three mixtures of silicone gel with viscoelastic properties similar to soft biological tissue that were tested in both the STA and a commercially available solids rheometer. The STA was used to perform stress relaxation tests on adult porcine brainstem to characterize the mechanical response of the brainstem. These experiments did not confirm our hypothesis of the brainstem\u27s transversely isotropic material response. Specifically, the calculated relaxation moduli did not vary with testing orientation. We hypothesized that due to the presence of significant relaxation in these tissues, the mechanical response of the brainstem is highly loading rate dependent. A series of dynamic oscillating shear tests in three mutually perpendicular directions were performed to further characterize the anisotropic nature of the brainstem at high loading rates. These experiments confirmed our hypothesis that the brainstem may be described as a transversely isotropic material; the complex moduli in the transverse direction were significantly higher than the other two moduli that were indistinguishable from one another. A novel fiber reinforced composite model composed of viscoelastic fibers surrounded by a viscoelastic matrix was developed to analyze the oscillatory shear data. The model predicted that the fibers are stiffer and more viscous than the surrounding matrix, a relationship reinforced by the results of the oscillatory shear tests. The predicted fiber modulus was confirmed by results of oscillatory shear tests on the optic nerve of the guinea pig

A characterization of the anisotropic mechanical properties of the brainstem

This research provided insight into the biomechanics of traumatic brain stem injury by characterizing the response of the brainstem to mechanical deformation. The brainstem is a region of the CNS characterized by axonal fibers longitudinally organized in parallel tracts. This distinct structure helps dictate the material response of the brainstem and suggests that this region may respond to mechanical insult as a transversely isotropic structure. The objective of this work was to investigate this assumption through material testing in three mutually perpendicular directions. A custom designed stress relaxation, oscillatory shear testing apparatus (STA) for testing soft biological tissues in simple shear was constructed and validated. The STA was validated by measurements of complex shear moduli of three mixtures of silicone gel with viscoelastic properties similar to soft biological tissue that were tested in both the STA and a commercially available solids rheometer. The STA was used to perform stress relaxation tests on adult porcine brainstem to characterize the mechanical response of the brainstem. These experiments did not confirm our hypothesis of the brainstem\u27s transversely isotropic material response. Specifically, the calculated relaxation moduli did not vary with testing orientation. We hypothesized that due to the presence of significant relaxation in these tissues, the mechanical response of the brainstem is highly loading rate dependent. A series of dynamic oscillating shear tests in three mutually perpendicular directions were performed to further characterize the anisotropic nature of the brainstem at high loading rates. These experiments confirmed our hypothesis that the brainstem may be described as a transversely isotropic material; the complex moduli in the transverse direction were significantly higher than the other two moduli that were indistinguishable from one another. A novel fiber reinforced composite model composed of viscoelastic fibers surrounded by a viscoelastic matrix was developed to analyze the oscillatory shear data. The model predicted that the fibers are stiffer and more viscous than the surrounding matrix, a relationship reinforced by the results of the oscillatory shear tests. The predicted fiber modulus was confirmed by results of oscillatory shear tests on the optic nerve of the guinea pig