The SceneScore for improved pre-hospital triage of motor-vehicle crash victims.

The SceneScore is a simple mechanism of injury scoring system designed to facilitate the appropriate triage of crash victims. It comprises 7 variables including age, collision type, impact location, airbag deployment, steering wheel deformity, intrusion, and restraint use. A cutoff value of 7 or 8 provides the maximum balance between sensitivity and specificity, with sensitivities of 75% to 83% and specificities of 29% to 46%. For cases triaged to the trauma center based only on high suspicion of injury, the SceneScore reduces the overtriage rate by almost half. Proper application of the SceneScore may lead to improved triage and enhanced communication of mechanism of injury criteria.

Age appropriate restraints for the right front passenger.

This study applies NASS/CDS, GES and FARS data to examine occupant exposure plus injury and fatality rates for belted occupants in frontal crashes by seating position, age and gender. The NASS data was used to examine the distributions by crash severity. The GES data showed that when two elderly occupants (age 65+) were present, the female occupied the right front passenger position 73% of the time. A paired comparison analysis using FARS data showed that, for elderly occupants (age 65+), the fatality risk for elderly right front passengers is 42% higher than for elderly drivers. The NASS/CDS analysis found 74% of the seriously injured vulnerable passengers with MAIS 3+ injuries were in crashes less severe than 26 mph. This group of injured occupants was made up of 43% aged 50 and older and 42% younger females. The injury rates for the older (age 50+) right front passengers were 1.8 times the rates for the elderly drivers. These results suggest the need for more benign safety systems for the right front passenger that are appropriate for the lower injury tolerance of the predominant occupants of that seating position.

Classification of rollovers according to crash severity.

NASS/CDS 1995-2004 was used to classify rollovers according to severity. The rollovers were partitioned into two classes - rollover as the first event and rollover preceded by an impact with a fixed or non-fixed object. The populations of belted and unbelted were examined separately and combined. The average injury rate for the unbelted was five times that for the belted. Approximately 21% of the severe injuries suffered by belted occupants were in crashes with harmful events prior to the rollover that produced severe damage to the vehicle. This group carried a much higher injury risk than the average. A planar damage measure in addition to the rollover measure was required to adequately capture the crash severity of this population. For rollovers as the first event, approximately 1% of the serious injuries to belted occupants occurred during the first quarter-turn. Rollovers that were arrested during the 1 ( st ) quarter-turn carried a higher injury rate than average. The number of quarter-turns were grouped in various ways including the number of times the vehicle roof faces the ground (number of vehicle inversions). The number of vehicle inversions was found to be a statistically significant injury predictor for 78% of the belted and unbelted populations with MAIS 3+F injuries in rollovers. The remaining 22% required crash severity metrics in addition to the number of vehicle inversions.

Residual injuries after recent safety improvements.

This study examines the residual injuries reported in NASS/CDS 1997-2004 by crash mode, crash severity, body region and occupant age. It examines how serious injuries are distributed in present day crashes and identifies opportunities for further injury reduction. In planar crashes, approximately 66% of the MAIS 3+ injuries occur in crashes less severe than 25 mph delta-V. Chest injuries predominate in these crashes, particularly among elderly occupants. A reduction in chest injuries to belted elderly occupants during low severity frontal crashes offers a prime opportunity for further improvement of safety systems. Younger occupants could also benefit from improved chest protection.

Characteristics of the injury environment in far-side crashes.

The population of occupants in far-side crashes that are documented in the US National database (NASS/CDS) was studied. The annual number of front seat occupants with serious or fatal injuries in far-side planar and rollover crashes was 17,194. The crash environment that produces serious and fatal injuries to belted front seat occupants in planar far-side crashes was investigated in detail. It was found that both the change in velocity and extent of damage were important factors that relate to crash severity. The median severity for crashes with serious or fatal injuries was a lateral delta-V of 28 kph and an extent of damage of CDC 3.6. Vehicle-to-vehicle impacts were simulated by finite element models to determine the intrusion characteristics associated with the median crash condition. These simulations indicated that the side damage caused by the IIHS barrier was representative of the damage in crashes that produce serious injuries in far-side crashes. Occupant simulations of the IIHS barrier crash at 28 kph showed that existing dummies lack biofidelity in upper body motion. The analysis suggested test conditions for studying far-side countermeasures and supported earlier studies that showed the need for an improved dummy to evaluate safety performance in the far-side crash environment.

Investigation of the performance of safety systems for protection of the elderly.

This study investigates injury occurrence for belted occupants as a function of age. An analysis of NASS/CDS 1997-2003 data was conducted to determine crash involvement rates and injury rates for front seat occupants versus mean occupant age. In frontal and near-side crashes, the average age of MAIS 3+ belted front seat occupants injured in crashes less severe than 15 mph is of the order of 50 years. The average age of the population exposed to crashes less severe than 15 mph is under 40 years old. The crash exposure and frequency if injuries to the elderly were both found to be the highest in low severity crashes. The chest is the most frequent body region injured for the elderly. These findings suggest the need for more benign safety systems to protect the elderly in low severity crashes. Design of safety systems for the elderly should give priority to reducing the chest loading in low severity frontal and near-side crashes.

Frequency of injuries in multiple impact crashes.

NASS 1998-2000 was queried to determine the frequency of serious injuries in multiple impact crashes and the distribution of injuries by crash sequence. The data set included all passenger cars and light trucks in NASS/CDS. The results showed that 42% of the MAIS 3+ injuries were in crashes that involved more than one harmful event. Approximately 24% of the MAIS 3+ injuries involved two harmful events, and 18% involved 3 or more harmful events. For multiple crashes with serious injuries, the most frequent initial impact direction was frontal (50%) followed by side (44.9%). The most frequent second impact was side (48.4%) followed by frontal (27.6%). The most harmful sequences were side-side (27.7%), front-side (15.8%) and front-front (14.9). The data suggests the need for further investigation and classification complex multiple impact crashes to aid in the in the design of safety systems.

Validation of the urgency algorithm for near-side crashes.

The URGENCY algorithm uses vehicle crash sensor data in Automatic Crash Notification (ACN) systems to assist in instantly identifying crashes that are most likely to have time critical injuries. The algorithm also provides the capability of improving injury identification, using data obtained from the scene. The prime purpose of the algorithm is to automatically provide emergency medical responders with objective information on crash severity to assist in detecting the approximately 1% of crashes with serious injuries needing the most urgent medical care. The algorithm calculates the risk of a MAIS 3+ injury being present in the crashed vehicle, instantly at the time of the crash. The prediction can be subsequently updated as more information becomes available. The algorithm was based on a multiple regression analysis using data from the National Accident Sampling System/Crashworthiness Data System, (NASS/CDS) years 1988-95. In this paper, the accuracy of the algorithm was evaluated for near side crashes by applying it retrospectively to the population of injured occupants in NASS 1997-2000. URGENCY was applied to the population of injured occupants in near side crashes. Using an injury risk criterion of 50%, URGENCY identified 69% of the crashes with MAIS 3+ injuries. By lowering injury risk criterion to 40%, URGENCY identified 78% of the crashes with MAIS 3+ injuries. Vehicle side intrusion was found to be a highly influential variable. By changing side intrusion from a binary to a continuous variable, the correctly identified crashes increased from 69% to 81%. Examination of the consequence of missing variables found that unknown values of occupant height and weight had a negligible effect on the ability to capture the MAIS 3+ injured. However, lack of knowledge of these variables did increase the magnitude of the false positives.

Development of a wheelchair occupant injury risk assessment method and its application in the investigation of wheelchair securement point influence on frontal crash safety.

To promote proper wheelchair securement in transportation, the proposed ANSI/RESNA Standard on Wheelchairs Used as Seats in Motor Vehicles will require that all transit wheelchairs be equipped with four securement points compatible with strap-type tiedowns. Through computer simulations, the location of these securement points has been found to influence wheelchair user response to a frontal crash. This study develops and employs an injury risk assessment method to compare the crashworthiness of various securement point configurations. The comparative injury risk assessment method is designed to predict the risk associated with internalized crash forces, as well as risk associated with secondary occupant impact with the vehicle interior. Injury criteria established by Federal Motor Vehicle Safety Standards and General Motors, along with excursion limitations set by the Society of Automotive Engineers (SAE) J2249 Wheelchair Tiedowns and Occupant Restraint Systems (WTORS) Standard were used as benchmarks for the risk assessment method. The simulation model subjected a secured commercial powerbase wheelchair with a seated 50th percentile male Hybrid III test dummy to a 20 g/30 mph crash. The occupant was restrained using pelvic and shoulder belts, and the wheelchair was secured with four strap-type tiedowns. Results indicated that securement points located 1.5 in to 2.5 in above the evaluated wheelchair's center of gravity provide the most effective occupant protection.

Dummy measurement of chest injuries induced by two-point shoulder belts.

The University of Miami's William Lehman Injury Research Center at the Jackson Memorial Medical Center conducts interdisciplinary investigations to study seriously injured restrained occupants in frontal automobile collisions. Engineering analysis of these crashes is conducted in conjunction with the National Crash Analysis Center at the George Washington University. The multidisciplinary research team includes expertise in crash investigation, crash reconstruction, computer graphics, biomechanics of injuries, crash data analysis, trauma care, and all of the medical specialties associated with the Ryder Trauma Center at Jackson Memorial Hospital. More than 350 injured occupants and their crashes have been studied in depth. The purpose of this paper is to report on an observed pattern of liver lacerations suffered by drivers wearing shoulder belts, without the lap belt fastened and to assess the ability of existing crash test dummies to measure the potential for these injuries. During the initial years of the study, 48 cases of drivers protected by shoulder belts but without the lap belt fastened met the criteria for the study. Fifty percent of these drivers suffered liver lacerations. Further study showed that 22 of the crashes involved damage to the right front of the vehicle. Among the drivers in vehicles with right front damage, 92% sustained injuries to the liver. This observation indicated that 2-point belts were most likely to produce liver injuries in low severity frontal collisions when the crash direction is 1 to 2 o'clock. An analysis of the National Accident Sampling System for the years 1988-95 indicated that liver injuries constitute about 0.5% of the injuries suffered by drivers who are in tow-away crashes. NASS data showed that the risk of chest injury is more likely among drivers with automatic shoulder belts than drivers with 3-point manual belts. The crash test dummies showed no difference in chest injury measures. Finite element computer modeling demonstrated that the high deflection of the right lower rib on the Hybrid III dummy predicts the liver injuries in the 1 o'clock crashes. These higher deflections were less apparent at the location of the center chest deflection measurement device on the Hybrid III.

Injuries to restrained occupants in far-side crashes.

Occupants exposed to far-side crashes are those seated on the side of the vehicle opposite the struck side. This study uses the NASS/CDS 1988-98 to determine distributions of AIS 3+ injuries among occupants exposed to far-side crashes and the sources of the injuries. The William Lehman Injury Research Center (WLIRC) data from 1994-98 is used to assess injury mechanisms among seriously injured crash exposed far-side occupants. The NASS/CDS indicated that injury patterns for far-side restrained drivers were different from far-side restrained front passengers. For the driver, the head accounted for 40% of the AIS 3+ injuries in far-side collisions and the chest/abdomen accounted for 45.5%. For the right front passengers, head injuries contributed 27.2%, while chest and abdominal injuries accounted for 64.5%. The opposite-side interior was the most frequent contact associated with driver AIS 3+ injuries (30.5%). The seat belt was second, accounting for 22.6%. Among thirteen WLIRC cases of far-side belted occupants with MAIS 3+ injuries, five of the most serious injuries were attributed to the seat belt. The liver or the spleen was the most seriously injured body organ in all five cases. The seat was the most frequent source of passenger AIS 3+ injuries for the NASS/CDS weighted cases. However, non-contacts, contacts with other occupants, and the seat belt contacts were more frequent sources when considering the raw number of injuries. Overall, contacts with the opposite side of the car interior and with safety belts were the most frequent causes of AIS 3+ injuries in far-side crashes. The presence of an occupant on the near-side changed the injury pattern of the far-side occupant, mitigating injuries from contacts with the opposite side interior of the vehicle.

Computer simulation and sled test validation of a powerbase wheelchair and occupant subjected to frontal crash conditions.

The Americans with Disabilities Act (ADA) has led to an increased number of wheelchair users seeking transportation services. Many of these individuals are unable to transfer to a vehicle and are instead required to travel seated in their wheelchairs. Unfortunately, wheelchairs are not typically designed with the same occupant protection features as motor vehicle seats, and wheelchair seated occupants may be at higher risk for injury in a crash. To study the effects of crash level forces on wheelchairs and their occupants, it is useful to simulate crash conditions using computer modeling. This study has used a dynamic lumped mass crash simulator, in combination with sled impact testing, to develop a model of a secured commercial powerbase and restrained occupant subjected to a 20 g/30 mph frontal motor vehicle crash. Time histories profiles of simulation-generated wheelchair kinematics, occupant accelerations, tiedown forces and occupant restraint forces were compared to sled impact testing for model validation. Validation efforts for this model were compared to validation results found acceptable for the ISO/SAE surrogate wheelchair model. This wheelchair-occupant simulation model can be used to investigate wheelchair crash response or to evaluate the influence of various factors on occupant crash safety.

Development of transportable wheelchair design criteria using computer crash simulation.

The Americans with Disabilities Act (ADA) has led to an increase in disabled travelers, many of whom are unable to transfer to a vehicle seat and are required to use their wheelchair to fulfill this function. ANSI/RESNA is currently developing a transportable wheelchair standard which will identify design requirements and testing methods for wheelchairs suitable for transport. Wheelchair manufacturers should begin to modify their existing design criteria established for a normal mobility function to design criteria appropriate for a transportation function which may subject the wheelchair to large dynamic crash forces. A thorough understanding of the crash environment and its effect on the wheelchair is necessary to insure the safety of the wheelchair user. To assist manufacturers in the design effort, this study uses mathematical crash simulations to evaluate loads imposed upon a wheelchair when subjected to a 48 kph/20 g frontal crash. Using a four-point belt tiedown system to secure the wheelchair, securement point, seat, lap belt anchor, and wheel loads are evaluated under three different securement configurations. Results show that positioning of rear securement points near the wheelchair center of gravity can serve as an effective strategy for managing crash response and loadings on the wheelchair. Force ranges for each of the evaluated parameters, derived for a 50th percentile male using a simulated power wheelchair, are provided for use as a preliminary guide when designing transportable wheelchairs.

Shoulder belt anchor location influences on wheelchair occupant crash protection.

An investigation of the effect of the shoulder belt's upper anchor point location on crash protection during wheelchair transportation was conducted using a lumped parameter crash victim simulator. While varying the upper anchor point location in each of three directions, the occupant kinematics and injury criteria of the Hybrid III test dummy were determined. Through comparison of these parameters and their associated trends, it was determined that varying the location of the anchor point has a significant effect on the crash protection of the occupant.

Light vehicle occupant ejections--a comprehensive investigation.

Occupant ejections, about 1.5% of all crash-involved occupant events, are relatively infrequent but very harmful events in highway crashes of light vehicles, including cars, pickup trucks, vans, and multipurpose vehicles (utility vehicles, jeeps, etc.). The disparity between frequency of harm to ejectees and ejection frequency is at least one order of magnitude. Partial ejections, although less frequent, have an incidence that is comparable to that of complete ejections, except for restrained occupants, where complete ejections are very infrequent. Notwithstanding the high effectiveness of safety belts in preventing ejections, and the multifold growth of safety belt use in the last 10 years, there is no detectable reduction in the ejection rate in the same period. Ejections per se and not other pre-ejection occupant impacts are responsible for the bulk of the harm to ejectees. Furthermore, ejected occupants sustain harm much larger than that which would have occurred, had these occupants not been ejected. "Closed glazing" is the leading ejection path. "Doors" and "windshield" are distant seconds. All glazing except the windshield fail overwhelmingly by disintegration. Latch failure is the primary mode of failure in opening doors. Hinges and other modes of failure are relatively minor concerns. The sources of data in this investigation are: the National Accident Sampling System for the years 1988 to 1991, and the Fatal Accident Reporting System for 1982 to 1992.

Occult abdominal injuries to airbag-protected crash victims: a challenge to trauma systems.

A multidisciplinary, automobile crash investigation team at the University of Miami School of Medicine, William Lehman Injury Research Center of Jackson Memorial Hospital/Ryder Trauma Center in Miami, Florida, is conducting a detailed medical and engineering study. The focus is restrained (seatbelts, airbag, or both) occupants involved in frontal crashes who have been severely injured. More than 60 crashes have been included in the study to date. Analysis of the initial data supports the general conclusion that restraint systems are working to reduce many of the head and chest injuries suffered by unrestrained occupants. However, abdominal injuries among airbag-protected occupants still occur. Some are found among occupants who appeared uninjured at the scene. Case examples are provided to illustrate abdominal injuries associated with airbag-protected crashes. The challenges of recognizing injuries to airbag-protected occupants are discussed. To assist in recognizing the extent of injuries to occupants protected by airbags, it is suggested that evidence from the crash scene be used in the triage decision. For the abdominal injury cases observed in this study, deformation of the steering system was the vehicle characteristic most frequently observed. The presence of steering wheel deformation is an indicator of increased likelihood of internal injury. This may justify transporting the victim to a trauma center for a closer examination for abdominal injuries.

Airbag and facebag benefits and costs.

There is debate about the appropriate design of supplementary airbags for passenger car occupants with high levels of seatbelt use. A theoretical analysis was performed to demonstrate the likely costs and benefits of U.S. fullsize driver airbags and the smaller European-style facebag. This study, undertaken for the Federal Office of Road Safety in Australia, builds upon previous work in this area. Benefits were determined using Harm Reductions for front-seat occupants involved in frontal crashes. A sensitivity analysis was undertaken for different benefit scenarios for the facebag, given the lack of available performance data. Likely costs of the components were derived from information provided by the local automobile manufacturers, part suppliers, and vehicle importers, with adjustments made for fitting to Australian vehicles. The results demonstrate the advantage of fullsize airbags over facebags, even when seatbelt wearing rates are high.

Forskolin and the release of noradrenaline in cerebrocortical slices.

The role of adenosine 3',5'-cyclic monophosphate (cAMP) in the release of noradrenaline from central neurones has been investigated by examining the effects of forskolin, 3-isobutyl-l-methylxanthine (IBMX), cis-6-(p-acetamidophenyl)-1,2,3,4,4a, 10b-hexahydro-8,9-dimethoxy-2-methyl-benzo[c] [1,6]-naphthyridine bis (+ +hydrogenmaleinate) (AH21-132; a new phosphodiesterase inhibitor) and N6,O2'-dibutyryl-adenosine 3',5'-cyclic monophosphate (dibutyryl-cAMP) on the outflow of tritiated compounds from rat and rabbit cerebral cortex slices preincubated with [3H]-noradrenaline. Forskolin, IBMX, AH21-132 and dibutyryl-cAMP produced a concentration-dependent increase in both basal and electrically-evoked efflux of tritium from rat and rabbit cortex slices. The increase in basal tritium efflux from rabbit cortex slices elicited by forskolin and IBMX could be attributed mainly to an increase in [3H]-DOPEG although a small increase in [3H]-noradrenaline was also observed. Forskolin and (when combined with noradrenaline) IBMX and AH21-132 increased the cAMP content of rat cortex slices at similar or somewhat higher concentrations that they increased tritium efflux. Neither forskolin nor IBMX or AH21-132 had any effect on the cocaine-sensitive uptake of [3H]-noradrenaline into synaptosomes prepared from rat or rabbit cortex. The effects of forskolin, IBMX and dibutyryl-cAMP on electrically-evoked overflow of tritium from rat and rabbit cortex slices were reduced when cocaine (10 microM) was present in the superfusion medium, although forskolin produced a similar increase in cAMP in the absence or presence of cocaine. It is suggested that cAMP may facilitate the normal process of noradrenaline release by nerve stimulation.

Effects of yohimbine stereoisomers on contractions of rat aortic strips produced by agonists with different selectivity for alpha 1- and alpha 2-adrenoceptors.

Three stereoisomers of yohimbine (corynanthine, rauwolscine and yohimbine) have been used to characterize alpha-adrenoceptors in rat aortic strips. pA2 values for each antagonist were calculated using 3 different agonists ((-)-noradrenaline, (-)-phenylephrine and guanfacine) which possess varying affinities for alpha 1 and alpha 2 receptors. Mean pA2 values were not significantly different irrespective of the agonist used and the order of the potency was corynanthine greater than yohimbine greater than rauwolscine. The results are consistent with the presence of alpha 1-adrenoceptors in rat aorta.

Characterization of postsynaptic alpha-adrenoceptors in rat aortic strips and portal veins.

Postsynaptic alpha-adrenoceptors in rat isolated aortic strips and portal veins have been examined using a number of agonist and antagonist drugs which have varying selectivity for alpha 1- and alpha 2-adrenoceptors. In both tissues (-)-noradrenaline [-)-NA), (-)-adrenaline [-) Adr) (-)-alpha-methyl noradrenaline [-)-alpha-Me-NA) and (-)-phenylephrine [-)-PE) were full agonists, while clonidine, oxymetazoline and (2-(2,6-dichlorophenyl)-5,6-dihydroimidazo(2,1,b) thiazole (44,549) were partial agonists. Guanfacine was a full agonist in aortic strips but only a partial agonist in portal veins. In aortic strips, pA2 values for prazosin and yohimbine were not significantly different using (-)-NA, (-)-PE or guanfacine as the agonist, suggesting a single population of alpha-adrenoceptors. The order of potency of the antagonists, prazosin = 2-(beta-(4-hydroxyphenyl)-ethylaminomethyl)-tetralone (BE2254) greater than phentolamine greater than yohimbine greater than rauwolscine, is indicative of an alpha 1-type of receptor. In portal veins, the order of potency of the antagonists was prazosin greater than BE2254 greater than phentolamine greater than yohimbine greater than rauwolscine, again indicating an alpha 1-type of receptor. The mean pA2 value for yohimbine was not significantly different in either tissue. However, mean pA2 values for prazosin, BE-2254 and phentolamine were approximately one order of magnitude lower in portal veins than in aortic strips, suggesting that the receptors in the two tissues may not be identical.