Dynamic injury tolerances for long bones of the female upper extremity.
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This paper presents the dynamic injury tolerances for the female humerus and forearm derived from dynamic 3-point bending tests using 22 female cadaver upper extremities. Twelve female humeri were tested at an average strain rate of 3.7+/-1.3%/s. The strain rates were chosen to be representative of those observed during upper extremity interaction with frontal and side airbags. The average moment to failure when mass scaled for the 5th centile female was 128+/-19 Nm. Using data from the in situ strain gauges during the drop tests and geometric properties obtained from pretest CT scans, an average dynamic elastic modulus for the female humerus was found to be 24.4+/-3.9 GPa. The injury tolerance for the forearm was determined from 10 female forearms tested at an average strain rate of 3.94+/-2.0%/s. Using 3 matched forearm pairs, it was determined that the forearm is 21% stronger in the supinated position (92+/-5 Nm) versus the pronated position (75+/-7 Nm). Two distinct fracture patterns were seen for the pronated and supinated groups. In the supinated position the average difference in fracture time between the radius and ulna was a negligible 0.4+/-0.3 ms. However, the pronated tests yielded an average difference in fracture time of 3.6+/-1.2 ms, with the ulna breaking before the radius in every test. This trend implies that in the pronated position, the ulna and radius are loaded independently, while in the supinated position the ulna and radius are loaded together as a combined structure. To produce a conservative injury criterion, a total of 7 female forearms were tested in the pronated position, which resulted in the forearm injury criterion of 58+/-12 Nm when scaled for the 5th centile female. It is anticipated that these data will provide injury reference values for the female forearm during driver air bag loading, and the female humerus during side air bag loading. (+info)
Driver distance from the steering wheel: perception and objective measurement.
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OBJECTIVES: This study assessed the accuracy of driver perceptions of the distance between the driver's nose and the steering wheel of the vehicle as a factor in considering driver disconnection of an airbag contained in the steering wheel for preventing injury to the driver in an accident. METHODS: A cross-sectional survey of 1000 drivers was done to obtain perceived and objective measurements of the distance between the driver's nose and the steering wheel of the vehicle. RESULTS: Of 234 drivers who believed that they sat within 12 inches of the steering wheel, only 8 (3%) actually did so, whereas of 658 drivers who did not believe that they sat within 12 inches of the wheel, 14 (2%) did so. Shorter drivers were more likely than taller ones to both underestimate and overestimate their seating distance. CONCLUSIONS: Considerable misperception of drivers' distance from the wheel indicates that drivers should objectively measure this distance. (+info)
Air bags and ocular injuries.
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PURPOSE: This investigation retrospectively examined ocular injuries associated with air bag deployment to gain a better appreciation of potential risk factors in motor vehicle accidents. National statistics regarding the efficacy of air bags were reviewed. METHODS: Review of the literature from 1991 to 1998 identified 44 articles describing 97 patients with air-bag-induced ocular injuries. Variables extracted from each case were age, sex, height, position in the car, eye wear, vehicle impact speed, visual acuity, and specific ocular injuries. RESULTS: Corneal abrasions occurred in 49% of occupants, hyphemas in 43%, vitreous or retinal hemorrhages in 25%, and retinal tears or detachments in 15%. The globe was ruptured in 10 patients. Patients involved in higher-speed accidents (over 30 mph) sustained a greater percentage of vitreous or retinal hemorrhages and traumatic cataracts, while those at slower speeds were more prone to retinal tears or detachments. In a subset of 14 patients with serious ocular injuries, the impact speed of 11 patients was recorded at 30 mph or less. Slower speed may be a risk factor for some ocular injuries. Occupant height was not a significant factor. National statistics confirm that air bags reduce fatalities in motor vehicle accidents. However, children sitting in the front seat without a seat belt and infants in passenger-side rear-facing car seats are at risk for fatal injury. CONCLUSION: Air bags combined with seat belts are an effective means of reducing injury and death in adults during motor vehicle accidents. However, this study has documented a wide variety of ocular injuries associated with air bag deployment. It is hoped that researchers can develop modifications that continue to save lives while minimizing additional harm. (+info)
Airbag associated fatal head injury: case report and review of the literature on airbag injuries.
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Airbags have been shown to significantly reduce mortality and morbidity in motor vehicle crashes. However, the airbag, like the seat belt, produces its own range of injuries. With the increasing use of airbags in the UK, airbag associated injuries will be seen more often. These are usually minor, but in certain circumstances severe and fatal injuries result. Such injuries have been described before in the medical literature, but hitherto most reports have been from North America. This is the first case report from the UK of serious injury due to airbag deployment and describes the case of a driver who was fatally injured when her airbag deployed in a moderate impact frontal collision where such severe injury would not normally have been anticipated. The range of airbag associated injuries is described and predisposing factors such as lack of seat belt usage, short stature, and proximity to airbag housing are discussed. The particular dangers airbags pose to children are also discussed. (+info)
Child seating position and restraint use in three states.
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OBJECTIVE: Because of risks from deploying airbags to children in front seats, extensive publicity has been aimed at getting them restrained and in rear seats. The objective of this study was to assess restraint use and seating positions among children in vehicles with and without airbags. METHOD: Surveys were conducted in cities in Michigan, North Carolina, and Texas 1998. Restraint use and seating position were noted for all children, as well as their estimated age, driver belt use, airbag presence, and vehicle license plate number. RESULTS: Fewer children were observed in the front seats of vehicles with passenger airbags (24%) than in vehicles without them (36%). Most of the children seated in front were ages 7-12 (44%-61%), followed by 3-6 year olds (29%-35%). Very few children ages 0-2 were seated in front (5%-12%). The overwhelming majority of children ages 0-2 were restrained. However, children ages 3-6 seated in the front were least likely to be restrained and most likely to be improperly restrained. Restraint use was higher when the driver was belted, but about 30% of 3-6 year olds were unrestrained even with a belted driver. CONCLUSIONS: Efforts should continue to educate parents about the importance of correct restraint use and rear seating for children, particularly once children move from child safety seats into adult belts. Efforts also should be made to enforce the seat belt laws that exist in every state. (+info)
Driver air bag effectiveness by severity of the crash.
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OBJECTIVES: This analysis provided effectiveness estimates of the driver-side air bag while controlling for severity of the crash and other potential confounders. METHODS: Data were from the National Automotive Sampling System (1993-1996). Injury severity was described on the basis of the Abbreviated Injury Scale, Injury Severity Score, Functional Capacity Index, and survival. Ordinal, linear, and logistic multivariate regression methods were used. RESULTS: Air bag deployment in frontal or near-frontal crashes decreases the probability of having severe and fatal injuries (e.g., Abbreviated Injury Scale score of 4-6), including those causing a long-lasting high degree of functional limitation. However, air bag deployment in low-severity crashes increases the probability that a driver (particularly a woman) will sustain injuries of Abbreviated Injury Scale level 1 to 3. Air bag deployment exerts a net injurious effect in low-severity crashes and a net protective effect in high-severity crashes. The level of crash severity at which air bags are protective is higher for female than for male drivers. CONCLUSIONS: Air bag improvement should minimize the injuries induced by their deployment. One possibility is to raise their deployment level so that they deploy only in more severe crashes. (+info)
Traumatic bilateral internal carotid artery dissection following airbag deployment in a patient with fibromuscular dysplasia.
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This case describes a 39-yr-old male, presenting with left hemiplegia after a road traffic accident involving frontal deceleration and airbag deployment. Brain computerized tomography (CT) scan revealed a right parietal lobe infarct. Contrast angiography demonstrated bilateral internal carotid artery dissection and fibromuscular dysplasia. The patient was treated with systemic heparinization. Neurological improvement, evidenced by full return of touch sensation, proprioception and nociception began 10 days after the injury. To our knowledge, this is the first case report of carotid artery dissection associated with airbag deployment. Forced neck extension in such settings may result in carotid artery dissection because of shear force injury at the junction of the extracranial and intrapetrous segments of the vessel. Clinicians should consider carotid artery injury when deterioration in neurological status occurs after airbag deployment. We propose that the risk of carotid artery dissection was increased by the presence of fibromuscular dysplasia. (+info)
Mortality reduction with air bag and seat belt use in head-on passenger car collisions.
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To assess the efficacy of occupant protection systems, the authors measured the mortality reduction associated with air bag deployment and seat belt use for drivers involved in head-on passenger car collisions in the United States. They used a matched case-control design of all head-on collisions involving two passenger cars reported to the Fatality Analysis Reporting System in 1992-1997, and driver mortality differences between the paired crash vehicles for air bag deployment and seat belt use were measured with matched-pair odds ratios. Conditional logistic regression was used to adjust for multiple effects. There were 9,859 head-on collisions involving 19,718 passenger cars and drivers. Air bag deployment reduced mortality 63% (crude odds ratio (OR) = 0.37, 95% confidence interval (CI): 0.32, 0.42), while lap-shoulder belt use reduced mortality 72% (OR = 0.28, 95% CI: 0.25, 0.31). In a conditional logistic model that adjusted for vehicle (rollover, weight, age) and driver (age, sex) factors, air bags (OR = 0.71, 95% CI: 0.58, 0.87) and any combination of seat belts (OR = 0.25, 95% CI: 0.22, 0.29) were both associated with reduced mortality. Combined air bag and seat belt use reduced mortality by more than 80% (OR = 0.18, 95% CI: 0.13, 0.25). Thus, this study confirms the independent effect of air bags and seat belts in reducing mortality. (+info)