Predictive value of heart rate deceleration capacity on coronary artery lesion in acute phase of Kawasaki disease.

This study was to investigate the correlation of vagal activity with coronary artery lesion (CAL) in Kawasaki disease (KD) children, and assess the predictive value of heart rate deceleration capacity (DC) for CAL in acute phase of KD.50 KD children with CAL, 130 KD children without CAL, 30 children with acute upper respiratory infection and 100 healthy children were recruited and indicators reflecting vagal activity including DC were measstuogram. KD children with CAL showed decreased vagal activity with significantly lower values of DC. DC was negatively correlated with levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) and C-reactive protein (CRP) in KD children. DC was a usable cardiac electrophysiological index to predict CAL in children with KD, with an area under the receiver operating characteristic curve (AUC) of 0.741. The cut-off value of DC for predicting CAL in KD children was 4.37 ms. DC was an independent predictor of CAL in children with KD, evaluated by multiple logistic regression analysis, KD children with DC ≤ 4.37 ms had an increased risk of CAL, with odds ratios (OR) of 5.94. Our study illustrates DC could be used to predict CAL in acute phase of KD.

[Rupture of the descending thoracic aorta following sudden traumatic deceleration injury]. / Rupture de l'aorte thoracique descendante suite à une décélération brutale post traumatique.

Acute post-traumatic rupture of the thoracic aorta is the second cause of road traffic deaths; 80% of patients die at the scene of the accident. The involvement of its descending portion outside the isthmus is rare and it is estimated to be less than 3%. We report the case of a 60-year old man, victim of road traffic accidents (RTA) whose mechanism was: the motorcyclist was struck by a car; the points of impact included the right upper limb and the chest. This RTA caused a fracture in both bones of the forearm and a rupture of the descending thoracic aorta (ATD). Treatment was based in the first time on the suture of the aortic rupture complemented by synthetic circumferential prosthesis implantation with aorto-aortic anastomosis and in a second time on the application of a screwed plate in the forearm. The outcome was good and the patient was referred to the Department of vascular surgery.

Determination of critical time points in non-collision incidents of elderly passengers in standing position on urban bus.

Objective: Due to the reduced physical ability of elderly, the occurrence of non-collision incidents is higher for these passengers in standing position. Therefore, the purpose of the present study is to determine the critical time points of non-collision incidents using the level of leg muscle activity in elderly standing passengers on urban bus.Methods: To determine the critical time points in the occurrence of non-collision incidents, the level of muscular activity of the standing passengers was analyzed using a surface electromyography (surface EMG) device during the movement scenario of the bus. The results of assessing the leg muscle activity was analyzed in SPSS software.Results: The contraction pattern of the leg muscles in standing passengers was consistent with Newton's First Law. The results showed that the level of muscular activity decreased in the right leg muscles when changing the phase of bus motion from acceleration to constant velocity. This level of muscular activity in the left leg muscles increased when constant velocity changed to deceleration. These changes were quite significant in the medial gastrocnemius and soleus muscles (P < 0.05).Conclusions: According to these findings, it was found that the acceleration and deceleration phases, especially the starting and changing phases of bus motion, are the most critical time points in the occurrence of non-collision incidents in elderly standing passengers on urban bus.

Optimal design alternatives of advance guide signs of closely spaced exit ramps on urban expressways.

Advance guide signs for exit ramps along urban expressways are increasingly critical, enhancing safety and mobility by improving the flow of vehicles exiting urban expressways. However, research has devoted scant attention to advance guide signs for exit ramps. This study aimed to identify and propose optimal design alternatives for exit ramp advance guide signs for different types of exit spacing. This study conducted a driving simulation experiment consisting of five design alternatives of advance guide signs and two exit ramp spacing variation. Eight indicators were measured. The repeated-measure analysis of variances (ANOVA) and the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) were performed for the influence analysis and efficiency evaluation of different schemes. Influence analysis results showed better design alternatives in five schemes of advance guide signs, enabling drivers to more easily locate destination exits and change lanes fewer times, in addition to reducing drivers' need to decelerate, and improving traffic flow in the key influence range of destination exit ramps. The percentage of drivers successfully locating the destination exits also increased with optimal design alternatives of advance guide signs. When the exit ramp spacing tightened, on the other hand, drivers had to make more lane changes and accelerate and decelerate more frequently in the key influence range. As a result, a lower percentage of drivers successfully located destination exits. Efficiency evaluation results were also obtained. In tight spacing, three advance guide signs are recommended to be placed at 1 km, 0.5 km and 0 km prior to the beginning of the tapered deceleration lane. If conditions are limited, at least two advance guide signs should be used. With greater spacing, four advance guide signs are recommended, located at 2 km, 1 km, 0.5 km, and 0 km prior to the beginning of the tapered deceleration lane. If road conditions are limited, three advance guide signs should be used.

A numerical investigation of factors affecting lumbar spine injuries in frontal crashes.

Recent field data analyses have shown that lumbar spine fractures occurred more frequently in late model vehicles than the early ones in frontal crashes. Therefore, the objective of this study was to investigate risk factors associated with lumbar spine fractures in frontal crashes. Parametric simulations were conducted using a set of validated vehicle driver compartment model, restraint system model, and a HIII mid-size male crash test dummy model. Risk factors considered in the study included occupant seating posture, crash pulse, vehicle pitch angle, seat design, anchor pre-tensioner, dynamic locking tongue, and shoulder belt load limiter. ANOVA and ANCOVA were used to test the statistical significance (p < 0.05). Simulation results showed that all the factors that reduced the risk of submarining increased the lumbar spine forces, indicating a direct conflict between submarining and lumbar spine fractures. Among all the factors selected, seat structure is the most significant factor in determining the lumbar spine force (p < 0.001). Crash pulse severity, time at which the peak crash deceleration reached, and pitch angle are also crucial for lumbar spine force. Specifically, increase in vehicle pitch angle increased lumbar spine force, but reduced injury measures to other body regions; while a crash pulse with early peak produced greater lumbar spine force than that with a late peak. On average, more reclined posture increased the lumbar spine force compared to upright posture, and decreases in the coefficient of friction between the pelvis and the seat cushion reduced the lumbar spine force. However, they are not statistically significant. This study provided better understanding of effects from design countermeasures to reduce occupant lumbar spine injuries in new generation of vehicle models.

Exploring microscopic driving volatility in naturalistic driving environment prior to involvement in safety critical events-Concept of event-based driving volatility.

The sequence of instantaneous driving decisions and its variations, known as driving volatility, prior to involvement in safety critical events can be a leading indicator of safety. This study focuses on the component of "driving volatility matrix" related to specific normal and safety-critical events, named "event-based volatility." The research issue is characterizing volatility in instantaneous driving decisions in the longitudinal and lateral directions, and how it varies across drivers involved in normal driving, crash, and/or near-crash events. To explore the issue, a rigorous quasi-experimental study design is adopted to help compare driving behaviors in normal vs unsafe outcomes. Using a unique real-world naturalistic driving database from the 2nd Strategic Highway Research Program (SHRP), a test set of 9593 driving events featuring 2.2 million temporal samples of real-world driving are analyzed. This study features a plethora of kinematic sensors, video, and radar spatiotemporal data about vehicle movement and therefore offers the opportunity to initiate such exploration. By using information related to longitudinal and lateral accelerations and vehicular jerk, 24 different aggregate and segmented measures of driving volatility are proposed that captures variations in extreme instantaneous driving decisions. In doing so, careful attention is given to the issue of intentional vs. unintentional volatility. The volatility indices, as leading indicators of near-crash and crash events, are then linked with safety critical events, crash propensity, and other event specific explanatory variables. Owing to the presence of unobserved heterogeneity and omitted variable bias, fixed- and random-parameter discrete choice models are developed that relate crash propensity to unintentional driving volatility and other factors. Statistically significant evidence is found that driver volatilities in near-crash and crash events are significantly greater than volatility in normal driving events. After controlling for traffic, roadway, and unobserved factors, the results suggest that greater intentional volatility increases the likelihood of both crash and near-crash events. A one-unit increase in intentional volatility is associated with positive vehicular jerk in longitudinal direction increases the chance of crash and near-crash outcome by 15.79 and 12.52 percentage points, respectively. Importantly, intentional volatility in positive vehicular jerk in lateral direction has more negative consequences than intentional volatility in positive vehicular jerk in longitudinal direction. Compared to acceleration/deceleration, vehicular jerk can better characterize the volatility in microscopic instantaneous driving decisions prior to involvement in safety critical events. Finally, the magnitudes of correlations exhibit significant heterogeneity, and that accounting for the heterogeneous effects in the modeling framework can provide more reliable and accurate results. The study demonstrates the value of quasi-experimental study design and big data analytics for understanding extreme driving behaviors in safe vs. unsafe driving outcomes.

Relationship between hazard-perception-test scores and proportion of hard-braking events during on-road driving - An investigation using a range of thresholds for hard-braking.

Drivers with higher proportion of hard braking events have greater potential to be involved in an accident. In this study, we tested if hard braking events might be accounted for by drivers' hazard perception (HP) ability. Our investigation was based on an original approach. Usually, researchers define hard braking according to a single deceleration threshold (e.g., g<-0.5). In this study, we chose different thresholds for hard braking (-0.25 to -0.6 g) and for each threshold, we examined the linkage between HP test (HPT) scores and the proportion of hard braking events. We hypothesized that this linkage would be stronger if the threshold that defines hard braking is higher. This is because the stronger the braking events, the higher the likelihood that they resulted from later detection of hazards and the lower the likelihood that they resulted from other causes (e.g., road humps). Thirty-three drivers completed an HPT and used a smartphone app that recorded their vehicle kinematics. We estimated the coefficient of HPT score in a series of binomial regression models on the proportion of hard braking events. In accordance with our hypothesis, we found that the coefficient of HPT score changed as a function of the threshold for hard braking. This finding was based on a significant negative Spearman correlation between the coefficients and the threshold and on linear functions that we derived from two binomial models that allowed the coefficient of HPT to vary according to the threshold. Our findings show that hard braking events are related to HP ability and can inform safety interventions in response to excessive proportion of hard braking events. In addition, they demonstrate that using a range of thresholds for hard braking is a practical tool in the study of hard braking events. From a theoretical perspective, our findings provide strong support to hazard perception theory.

Longitudinal safety impacts of cooperative adaptive cruise control vehicle's degradation.

INTRODUCTION: The adaptive cruise control (ACC) and cooperative ACC (CACC) systems are critical parts of self-driving vehicles. The ACC vehicles detect front vehicle' information via vehicle-mounted sensors and make longitudinal reactions automatically, while CACC vehicles enhance the performance by vehicle-to-vehicle (V2V) wireless communication. However, CACC vehicles may abruptly degrade to ACC mode in reality due to various reasons, including communication failures, driver manipulations, and cyber-attacks. The sudden degradation will definitely bring negative influences on safety. METHOD: This study quantitatively evaluated the longitudinal safety impacts of vehicles' degradation in a CACC fleet based on microscopic simulations. The realistic CACC and ACC models proposed by the California Partners for Advanced Transit and Highways (PATH) were used for simulation experiments. The time integrated time-to-collision (TIT) was measured to quantify the collision risks. Extensive simulations were conducted via a fleet of 10 CACC vehicles and speed profiles of vehicles in different scenarios were compared. Key factors, including the leading vehicle's deceleration rate, the number of vehicles between degraded vehicles (NVDVs), threshold of TTC, and visibility were also examined via sensitivity analyses. RESULTS AND CONCLUSIONS: Simulation results indicate that degradation has significant negative influences on longitudinal safety of degraded vehicles under the driving state of deceleration. Degradation at middle positions in a CACC fleet, such as fourth and fifth positions, is much safer than that at others. Moreover, nonadjacent degradation is much riskier than adjacent degradation at the front positions of a fleet. NVDVs can bring inverse impacts on safety with different degradation positions. Speed profiles imply that the hysteresis of degraded vehicles' speed control is the major reason for high collision risks. Practical applications: Appropriately, hierarchical countermeasures have the potential to reduce the longitudinal safety impacts of degradation. Findings of this study can contribute to determining the applicable length of CACC fleets.

Deceleration, Acceleration, and Impacts Are Strong Contributors to Muscle Damage in Professional Australian Football.

Gastin, PB, Hunkin, SL, Fahrner, B, and Robertson, S. Deceleration, acceleration, and impacts are strong contributors to muscle damage in professional Australian football. J Strength Cond Res 33(12): 3374-3383, 2019-The purpose of this study was to investigate the relationships between serum creatine kinase [CK], an indirect marker of muscle damage, and specific indices of match load in elite Australian football. Twenty-six professional players were assessed during a competitive Australian Football League (AFL) season. [CK] was collected 24-36 hours before match and 34-40 hours after match during 8 in-season rounds. An athlete-tracking technology was used to quantify match load. Generalized estimating equations and random forest models were constructed to determine the extent to which match-load indices and pre-match [CK] explained post-match [CK]. There was a 129 ± 152% increase in [CK] in response to AFL competition. Generalized estimating equations found that number of impacts >3g (p = 0.004) and game time (p = 0.016) were most strongly associated with post-match [CK]. Random forest, with considerably lower errors (130 vs. 316 U·L), found deceleration, acceleration, impacts >3g, and sprint distance to be the strongest predictors. Pre-match [CK] accounted for 11% of post-match [CK], and considerable interindividual and intraindividual variability existed in the data. Creatine kinase, an indicator of muscle damage, was considerably elevated as a result of AFL competition. Parametric and machine-learning analysis techniques found several indices of physical load associated with muscle damage during competition, with impacts >3g and high-intensity running variables as the strongest predictors. [CK] may be used as a global measure of muscle damage in field team sports such as AF, yet with some caution given cost, invasiveness, and inherent variability. Quantifying physical load and the responses to that load can guide athlete management decision-making and is best undertaken within a suite of practical, sport-specific measures, where data are interpreted individually and with an understanding of the limitations.

Deceleration thoracic aortic ruptures in trauma center level I areas: a 6-year retrospective study.

OBJECTIVES: This retrospective study aimed to analyze the trend of mortality due to thoracic aortic ruptures caused by deceleration injuries that occurred within the catchment area of Hradec Kralove University Hospital. MATERIALS AND METHODS: The study sample comprised 175 patients who had sustained thoracic aortic ruptures caused by deceleration injuries and were transported to Hradec Kralove University Hospital in 2009-2014. The small proportion of patients enrolled in this retrospective study were diagnosed and treated at the emergency department (ED). However, the overwhelming majority of the sample comprised of patients who died at the accident scene and later underwent an autopsy at the Institute of Forensic Medicine in our hospital. RESULTS: Of 175 patients, 150 underwent an autopsy. Of these, 139 individuals (79%) died at the incident scene, and 11 (6%) were transported to the ED and later died of their injuries. A total of 36 patients were admitted to the hospital; 29 were admitted primary (11 later died), and 7 were transferred. No deaths occurred in the group of secondary admissions. Thus, 31% of all patients hospitalized died following transport to the hospital. Of 175 patients, 15% (or 69% of all hospitalized patients) survived their injuries. Among patients who died as a result of thoracic aortic injury, no unexpected deaths were recorded (i.e., no deaths among patients with survival probability more than 50% = PS > 0.5). CONCLUSION: Our results suggested that the lethality of thoracic aortic injuries might be minimized by transporting triage-positive patients directly to trauma centers. Accurate diagnoses and treatments were supported by admission chest X-rays, a massive transfusion protocol, and particularly, CT angiography, which is not routinely included in primary surveys. An additional prognostic parameter was clinical collaboration between an experienced trauma surgeon, an interventional radiologist, and a vascular or thoracic surgeon.

The effect of gender, occupation and experience on behavior while driving on a freeway deceleration lane based on field operational test data.

Deceleration lanes improve traffic flow by reducing interference, increasing capacity and enhancing safety. However, accident rates are higher on these interchange segments than on other freeway segments. It is important to attempt to reduce traffic accidents on these interchange segments by further exploring the behavior of different types of drivers on a highway deceleration lane. In this study, with field operational test (FOT) data from 89 driving instances (derived from 46 participants driving the test road twice) on a typical freeway deceleration lane, section speed profiles, vehicle trajectories, lane position and other key parameters were obtained. The lane-change characteristics and speed profiles of drivers with different genders, occupations and experiences were analyzed. The significant disparities between them reflects the risk associated with different groups of drivers. The study shows that male drivers changed to the outside lane earlier; professional drivers and experienced drivers made the last lane change as early as possible to enter the deceleration lane; and the speed of the vehicles entering the exit ramp was significantly higher than the speed limit. This research work provides ground truth data for deceleration lane design, driver ability training and off-ramp traffic safety management.

Hangman's Fracture Caused by Parachute Opening Deceleration Captured on Video.

BACKGROUND: Nonlethal cervical spine injuries in skydiving are rare due to the associated high mortality. Here, we report an unusual pathomechanism leading to a Hangman fracture in a semiprofessional parachute athlete. CASE DESCRIPTION: The moment of injury was captured on a first-person video and identified as a rough parachute opening deceleration during canopy deployment, caused by failure of the parachute inflation control device. Fractures of the C2 pars interarticularis with C2/C3 instability were treated by anterior cervical diskectomy and fusion, and the patient reached full recovery. CONCLUSIONS: Excessive deceleration during canopy deployment may pose a risk for life-threatening cervical spine injuries in skydiving.

[Traumatic dissection of the left renal pedicle in a young adult]. / Dissection traumatique de l'artère rénale gauche chez un adulte jeune.

Blunt trauma rarely causes renal pedicle dissection. Clinical signs are minimal and inconsistently reported. The diagnosis is based on computed tomographic angiography; arteriography is still useful when revascularization is considered. We report here a case of traumatic dissection with thrombosis of a juxta-aortic renal pedicle monitored in the intensive care unit. An endovascular procedure could not be proposed because of the juxta-aortic localization.

Skydiving and the risk of cervical disc herniation.

The skydiving/parachuting sport which has recently gained popularity is also known for its accidents and injuries. However, there are a few studies related to its occupational ergonomic risks and occupational musculoskeletal diseases. It has been reported that the sudden hyperextension of the neck during the parachute opening, so called opening shock results in neck pain. It has been found that the jumpers are subjected to an average deceleration of 3-5 times the earth's gravitational acceleration (3-5 G) during parachute opening shock. It is considered that the spinal cord is destabilized by the impact of this force. This study presents the occupational cervical disc herniation occurring in the case of a subject who has been working as a skydiving/parachuting instructor for 25 years, and the ergonomic risks specific to the sports of skydiving. There is a requirement for systematic and representative studies related to the administrative measures to be taken in order to prevent the occupational diseases that may occur in the case of skydivers, the personal protective equipment to be used, and the employee. Int J Occup Med Environ Health 2018;31(2):243-249.

Patient Litter System Response in a Full-Scale CH-46 Crash Test.

U.S. Military aeromedical patient litter systems are currently required to meet minimal static strength performance requirements at the component level. Operationally, these components must function as a system and are subjected to the dynamics of turbulent flight and potentially crash events. The first of two full-scale CH-46 crash tests was conducted at NASA's Langley Research Center and included an experiment to assess patient and litter system response during a severe but survivable crash event. A three-tiered strap and pole litter system was mounted into the airframe and occupied by three anthropomorphic test devices (ATDs). During the crash event, the litter system failed to maintain structural integrity and collapsed. Component structural failures were recorded from the litter support system and the litters. The upper ATD was displaced laterally into the cabin, while the middle ATD was displaced longitudinally into the cabin. Acceleration, force, and bending moment data from the instrumented middle ATD were analyzed using available injury criteria. Results indicated that a patient might sustain a neck injury. The current test illustrates that a litter system, with components designed and tested to static requirements only, experiences multiple component structural failures during a dynamic crash event and does not maintain restraint control of its patients. It is unknown if a modern litter system, with components tested to the same static criteria, would perform differently. A systems level dynamic performance requirement needs to be developed so that patients can be provided with protection levels equivalent to that provided to seated aircraft occupants.

Evaluation of 6 and 10 Year-Old Child Human Body Models in Emergency Events.

Emergency events can influence a child's kinematics prior to a car-crash, and thus its interaction with the restraint system. Numerical Human Body Models (HBMs) can help understand the behaviour of children in emergency events. The kinematic responses of two child HBMs-MADYMO 6 and 10 year-old models-were evaluated and compared with child volunteers' data during emergency events-braking and steering-with a focus on the forehead and sternum displacements. The response of the 6 year-old HBM was similar to the response of the 10 year-old HBM, however both models had a different response compared with the volunteers. The forward and lateral displacements were within the range of volunteer data up to approximately 0.3 s; but then, the HBMs head and sternum moved significantly downwards, while the volunteers experienced smaller displacement and tended to come back to their initial posture. Therefore, these HBMs, originally intended for crash simulations, are not too stiff and could be able to reproduce properly emergency events thanks, for instance, to postural control.

[Delayed liver hematoma development following deceleration injury]. / Pozdní vznik hematomu jater po deceleracním traumatu.

Our report presents the case of a young woman who suffered liver trauma after electrical current injury and ensuing fall from an electricity pylon. The resulting intrahepatic hematoma manifested after a time interval of 48 hours following the injury, with initially negative CT scan.Key words: liver hematoma electrical current - polytrauma burns.

Odontoid fracture biomechanics.

STUDY DESIGN: In vitro biomechanical study. OBJECTIVES: To investigate mechanisms of odontoid fracture. SUMMARY OF BACKGROUND DATA: Odontoid fractures in younger adults occur most often due to high-energy trauma including motor vehicle crashes and in older adults due to fall from standing height. METHODS: Horizontally aligned head impacts into a padded barrier were simulated using a human upper cervical spine specimen (occiput through C3) mounted to a surrogate torso mass on a sled and carrying a surrogate head. We divided 13 specimens into 3 groups on the basis of head impact location: upper forehead in the midline, upper lateral side of the forehead, and upper lateral side of the head. Post-impact fluoroscopy and anatomical dissection documented the injuries. Time-history biomechanical responses were determined. RESULTS: Four of the 5 specimens subjected to impact to the upper forehead in the midline sustained type II or high type III odontoid fractures due to abrupt deceleration of the head and continued forward torso momentum. Average peak force reached 1787.1 N at the neck at 50.3 milliseconds. Subsequently, the motion peaks occurred for the head relative to C3 reaching 15.2° for extension, 2.1 cm for upward translation, and 5.3 cm for horizontal compression, between 62 and 68 milliseconds. CONCLUSION: We identified impact to the upper forehead in the midline as a mechanism that produced odontoid fracture and associated atlas and ligamentous injuries similar to those observed in real-life trauma. We were not able to create odontoid fractures during impacts to the upper lateral side of the forehead or upper lateral side of the head. Dynamic odontoid fracture was caused by rapid deceleration of the head, which transferred load inferiorly combined with continued torso momentum, which caused spinal compression and anterior shear force and forward displacement of the axis relative to the atlas.

Pre-activation and muscle activity during frontal impact in relation to whiplash associated disorders.

OBJECTIVE: For the evaluation of neck injury the relative distance was observed between a marker placed on the forehead and a marker placed on the shoulder and also by change of the angle. To compare the severity of head injury a value of maximum head acceleration was used, HIC and a 3 ms criterion. All criteria were related to the activity of musculus sternocleidomastoideus and musculus trapezius in a situation of expected or unexpected impact. MATERIALS AND METHODS: The situation was recorded using a Qualisys system, head acceleration of probands in three axes was recorded using the accelerometer, activity of neck muscles was monitored by a mobile EMG. RESULTS: Maximum head acceleration was 12.1 g for non-visual and 8.2 g for visual. HIC36 was 5.7 non visual and 4.0 for visual. 3-ms criterion was 11.5 g for non-visual and 7.8 g for visual. The average time of muscle activation of the observed group without visual perception is 0.027 s after hitting an obstacle, with visual perception 0.127 s before the crash. CONCLUSIONS: Kinematic values indicate more favourable parameters for neck injuries for visual. Head injury criteria show an average decrease of about 30% for visual. We can conclude that the visual perception means a significant increase in pre-activation of the observed muscle group of almost 400% and lower activation in both following phases of approximately 40%.