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PubMed2003

Effect of airbag deployment on head injuries in severe passenger motor vehicle crashes in Ontario, Canada.

BACKGROUND: The purpose of this study was to identify and analyze factors contributing to both airbag deployment and resulting head injuries (HIs) and to quantify the effect of airbag deployment on head injuries, in terms of odds of head injury and severity, in severe motor vehicle collisions (MVCs). METHODS: Data were derived from severely injured (Injury Severity Score [ISS] > 12) drivers treated at Ontario's lead trauma hospitals (n = 1,272), and included all MVC driver deaths in the province (n = 665) from 1997-98. We conducted an epidemiologic description and a case-control study to compare drivers with and without HIs. Statistical analysis included Pearson's chi2, Wilcoxon rank-sum, and multiple logistic regression tests. RESULTS: Seventy-one percent of drivers were men, peaking in the 25- to 34-year age group. The most common impact involved multiple vehicles (62%) approaching each other. Overall, 59% of crashes had a frontal location of impact. HIs were significantly associated with a lower age (median, 36 vs. 43 years), seat belt use (53% vs. 59%), and airbag deployment (7% vs. 10%), with higher ISS (median, 34 vs. 22), ejection (20% vs. 10%), and mortality rate (44% vs. 35%). Airbag deployment was associated with higher age and seat belt use, and lower ISS, ejection, and deaths. Importantly, there were fewer HIs with the deployment of an airbag (64% vs. 73%) and a lower severity of HI. When logistic regression was used to control for the effects of possible confounders, airbag deployment was not statistically associated with one's odds of HI (odds ratio, 0.827; 95% confidence interval, 0.560-1.220), but ISS, age, and ejection were. CONCLUSION: Airbag deployment did not significantly lower a driver's odds of head injury in a severe MVC, but it did significantly lower the severity of head injury. This is a significant finding, given that 72% of our study population sustained a head injury and the importance of lowering the severity of these head injuries in terms of patients' ultimate outcome. The most important factor associated with head injuries was ejection, which nearly doubled a driver's odds of head injury (odds ratio, 1.759; 95% confidence interval, 1.201-2.577). This reinforces the supplementary protective effect of an airbag and that "buckling up" and keeping occupants in the vehicle is of primary importance in the prevention of head injuries.

Accidents, Traffic↗
PubMed1996

Traumatic thoracic aortic rupture in the pediatric patient.

BACKGROUND: Traumatic thoracic aortic rupture is a rare injury in the pediatric patient. Experiences with thoracic aortic rupture in patients less than 17 years of age are needed to help identify factors that can influence injury occurrence, diagnosis, management, and outcome. METHODS: Between July 1989 and December 1995, 6 children were treated operatively for thoracic aortic rupture from blunt trauma at a level I pediatric trauma center. The average age was 13.2 years (range, 8 to 16 years). There were 4 females and 2 males. There were 5 motor vehicle accidents and 1 bicycle accident. Aortic injury was suspected based on the mechanism of injury and abnormal chest roentgenogram results, and was confirmed by aortography (3 cases) or chest computed tomography (2) and transesophageal echocardiography (3). Life-threatening central nervous system or gastrointestinal injuries were evaluated or treated first. Operative repair of the thoracic aorta was performed by cardiopulmonary bypass (2 patients) and clamp and sew technique (4). RESULTS: Aortic ruptures were complete transections at the ligamentum arteriosum in 5 of 6 (83%); the other case was a cervical arch pseudoaneurysm. Associated injuries included pulmonary contusion (100%), pelvic/long bone fractures (50%), visceral laceration/perforation (50%), central nervous system (33%), paraplegia (17%), and myocardial contusion (17%). There were no rib fractures. Four of 5 patients (80%) were not wearing seat belts, and 2 of these were ejected. The average time from injury to the operating room was 17.6 hours (range, 5 to 48 hours); the time from diagnosis to the operating room exceeded 5 hours with aortography and was less than 3 hours with chest computed tomography and transesophageal echocardiography. Each diagnostic modality accurately identified an aortic injury. The average time for cardiopulmonary bypass and for clamp and sew was 52 minutes (range, 49 to 55 minutes) and 34 minutes (range, 16 to 45 minutes), respectively. One patient with preoperative paraplegia regained partial function; there were no other patients with paraplegia. There were no deaths. All patients are alive 2 months to 7 years after repair. CONCLUSIONS: The multiply injured child with severe blunt trauma and an abnormal chest roentgenogram requires a search for aortic injury. We believe the most effective algorithm to follow for the diagnosis of traumatic thoracic aortic rupture in the child involves selective performance of chest computed tomography and transesophageal echocardiography. Our experience suggests that the mechanism of injury, the duration to diagnosis of an aortic injury, and failure to use seat belts may contribute to morbidity. A high index of suspicion and a systematic approach to the diagnosis and to the management strategy for injuries to the thoracic aorta can contribute to a good outcome in those few children who survive the injury.

Adolescent↗
PubMed2005

Low speed vehicle passenger ejection restraint effectiveness.

Current golf carts and LSV's (Low Speed Vehicles) produce a significant number of passenger ejections during sharp turns. These LSV's do not typically possess seatbelts, but do provide outboard bench seat hip restraints that also serve as handholds. However, many current restraint designs appear incapable of preventing passenger ejections due to their low height and inefficient handhold position. Alternative handhold and hip restraint designs may improve passenger safety. Accordingly, this paper examines minimum size requirements for hip restraints to prevent passenger ejection during sharp turns and evaluates the effectiveness of a handhold mounted at the center of the bench seat. In this study, a simulation of a turning cart supplies the dynamic input to a biomechanical model of an adult male seated in a golf cart. Various restraint combinations are considered, both with and without the central handhold, to determine the likelihood of passenger ejection. It is shown that only the largest restraint geometries prevent passenger ejection. Adequate hip restraints should be much larger than current designs and a central handhold should be provided. In this way, golf cart and LSV manufacturers could reduce passenger ejections and improve fleet safety by incorporating recommendations provided herein.

Accident Prevention↗
PubMed1980

[25 cases of traumatic rupture of the thoracic aorta: current diagnostic elements].

Traumatic rupture of the descending thoracic aorta is lethal within 3 weeks in 95% of patients who do not undergo operation. In this series of 25 patients who were operated on, 84% have survived for 6 years and there have been no cases of paraplegia. The mechanism of injury is most important in the investigation of patients with traumatic injuries and must be sought either from the patient or from witnesses. A history of rapid deceleration (more than 60 km/h) following a highway collision was present in all our cases. Failure to wear seat-belts resulted in 70% of patients being ejected from a vehicle. A side-on collision resulting in lateral deceleration caused trauma to the intrathoracic aorta in 45% of cases. Vertical deceleration resulted from falls from great heights (bridge, overpass) in 25% of cases. Clinical signs of diagnostic importance were: arterial hypertension (60%), systolic murmur (35%) and the pseudocoarctation syndrome (25%). Pertinent signs on chest roentgenograms were present in 95% of cases and included widening of the mediastinum and blunting of the aortic knob. The authors conclude thoracic aortography should be carried out in trauma patients when two or more of the following are present: (a) history of rapid deceleration, ejection from a vehicle or lateral collision, (b) hypertension and (c) blunting or modification of the aortic knob. The presence of a pseudocoarctation syndrome is an absolute indication for aortography.

Accidents, Traffic↗
PubMed2002

Systemic vascular resistance during brief withdrawal of angiotensin converting enzyme inhibition in heart failure.

We tested the hypothesis that moderate increases in endogenous angiotensin II (Ang II) concentrations, induced by withdrawal of angiotensin converting enzyme inhibition (ACE-I) in patients with compensated heart failure (HF) on chronic medical therapy, do not increase or impair control of systemic vascular resistance (SVR). SVR was determined in supine and seated positions in 12 HF patients [NYHA class II-III; ejection fraction=0.29 +/- 0.03 (mean +/- SE)] and 9 control subjects. HF patients were investigated during high (n=11; withdrawal of ACE-I treatment for 24 h) and low (n=9; sustained ACE-I therapy) endogenous plasma Ang II concentrations. Withdrawal of ACE-I therapy in HF caused moderately increased Ang II concentrations of 30 +/- 5 pg/ml compared with 12 +/- 2 pg/ml in controls (p<0.05 vs. HF patients). Despite this, SVR was similar in HF (supine: 1503 +/- 159; seated: 1957 +/- 262 dyn s/cm5, p<0.05 vs. supine) and controls (supine: 1438 +/- 104; seated: 1847 +/- 127 dyn s/cm5, p<0.05 vs. supine). During sustained ACE-I therapy in HF, plasma Ang II concentrations were lower (6 +/- 2pg/ml, p<0.05 vs. withdrawal of ACE-I in HF) with no effect on supine SVR. However, the posture-induced increase in SVR in response to the seated position was attenuated. In conclusion, brief moderate increases in circulating plasma Ang II concentrations in compensated HF do not increase SVR compared to control subjects or impair control of SVR in response to a posture change.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1989

Impedance-derived cardiac indices in supine and upright exercise.

Impedance cardiography was used to determine the classical systolic time intervals (STI's) (i.e., pre-ejection period (PEP), left ventricular ejection time (LVET) and the quotient PEP/LVET), in young, healthy, male subjects during supine and seated exercise. With increasing exercise, there was a tendency toward decreases in PEP, LVET, and PEP/LVET. In the seated position, there was an increase in transthoracic Zo incident to the caudal migration of thoracic blood--a result of the postural change. With seated exercise, there were--in contrast to supine exercise-greater decreases in PEP/LVET and greater increases in the Heather index. Similarly, there was a tendency toward increases in dZ/dtmin and the Rapid Ejection Index. We suggest that these differences are related to increased myocardial contractility resulting from the postural augmentation of cardio-sympathetic activity, added to that of exercise per se. This study, as well as previous ones, indicates that impedance cardiography is reliable, effective, and more practicable than the arteriographic method for monitoring STI's. We also believe that certain impedance-derived indices (i.e., transthoracic Zo, dZ/dtmin and the Heather Index) have considerable potential value for physiologic and clinical investigation.

Adult↗
PubMed1989

Reduction in accident injury severity in rear seat passengers using restraints.

A prospective study of 441 rear seat occupants seen following road traffic accidents compared injury severity in the 411 unrestrained and 30 restrained subjects. Using ridit analysis, the injury severity score showed far less injury among restrained subjects (P = 0.0001). All 11 deaths and 176 of the 178 most severe injuries occurred in the unrestrained group. One restrained (3 per cent) subject was admitted overnight and 64 unrestrained (16 per cent) subjects required admission; two-thirds required a prolonged admission (mean = 13 days). Fractures, major bruises, abrasions and lacerations were almost confined to unrestrained passengers, 221 events compared with two among restrained passengers. Twenty-three unrestrained subjects were ejected, nine of whom were killed. We conclude that the use of rear seat restraints greatly reduces injury severity and should be compulsory for rear seat occupants as it is for front seat occupants.

Accidents, Traffic↗
PubMedDate not supplied

Forces, moments, and acceleration acting on a restrained dummy during simulation of three possible accidents involving a wheelchair negotiating a curb: comparison between lap belt and four-point belt.

The objective of this study was to determine the effect of two types of restraining belts (lap belt and a four-point belt) on an instrumented dummy during three situations: wheelchair hitting straight into curb (SIC); wheelchair falling straight off a curb (SOC); wheelchair falling diagonally off a curb (DOC). A fully instrumented (50th percentile Hybrid III) dummy was seated in a standard wheelchair and restrained with one of the belts. The wheelchair rolled down a ramp reaching a platform at 2.4 miles per hour (comfortable walking speed). Three types of experiments were performed: SIC, SOC, DOC. Each experiment was repeated at least three times. Forces, moments, and acceleration were monitored and recorded via 48 sensors placed at the head, spine, and limbs. All experiments were videotaped and photographed. The data were averaged and compared with standards that have been previously established in car crash testing and with data recently obtained in a similar study using a nonrestrained dummy. Our results showed that in the SIC experiments, low magnitude forces, moments, and acceleration of no clinical significance were recorded with both types of belts. The wheelchair remained upright and the dummy safely seated. In the SOC experiments, the two belts prevented the dummy's ejection from the chair and, thus, have been effective in lowering the forces, moments, and acceleration and preventing significant injuries to the head and neck regions. In the DOC experiments, the lap belt proved to be somewhat more effective than the four-point belt in lowering the extension forces at the upper neck and the moments at the lower neck below injury levels. It also kept the head injury criteria well below injury level. We postulate that the four-point belt was less effective because of its more extensive body fixation, which leads to concentration of moments and forces at the head and lower neck regions. The results of this study show that restraining systems can enhance the safety of wheelchair occupants in certain incidents. It has been demonstrated that the lap belt is as effective as the four-point belt system in SIC and SOC incidents. In DOC falls, neither belt could prevent falls and trauma to the head and neck region. The lap belt, however, was somewhat superior. We recommend that wheelchairs be equipped with a lap belt and patients be encouraged to buckle-up while using the wheelchair outdoors.

Acceleration↗
PubMed2001

Shoulder belts in motor vehicle crashes: a statewide analysis of restraint efficacy.

The purpose of our study was to evaluate the impact of shoulder belt use on motor vehicle crash ejection, morbidity and mortality. We analyzed motor vehicle crash records linked to hospital inpatient data for front seat occupants of passenger cars in Utah between 1994 and 1996 (n = 103,035). Stochastic simulations were used to adjust for possible seatbelt misclassification. There were 276 (0.3%) occupants coded as using only a shoulder belt. The adjusted odds of ejection for shoulder only belted occupants was higher compared to lap-shoulder belted (odds ratio (OR) = 18.9; 95% confidence interval (CI) = 15.1, 25.1) and lap only belted occupants (OR = 4.3; 95% Cl = 2.9, 7.7). There was no difference in the odds of ejection for an occupant using a shoulder belt only and an occupant using no seatbelt (OR = 1.1; 95% CI = 1.0, 1.3). Occupants using a shoulder belt only were more likely to sustain a fatal or hospitalizing injury than lap-shoulder belted (OR = 2.3; 95% Cl = 1.9, 3.0), and lap only belted occupants (OR = 1.8; 95% CI = 1.3, 2.7), while controlling for other covariates. Occupants using only a shoulder belt had the same odds of a fatal or hospitalizing injury as unbelted occupants (OR = 1.1; 95% Cl = 0.9, 1.4). Average hospital inpatient length of stay, charges and injury severity scores were similar for all restraint types. These results stress the need for the use of a lap belt in conjunction with the shoulder belt.

Accidents, Traffic↗
PubMed1994

Deaths from motor vehicle crashes: patterns of injury in restrained and unrestrained victims.

A time comparison study of motor vehicle crashes in Monroe County, New York, from 1983 to 1986 was completed. Using a database of police accident reports, hospital logs, and autopsy reports from the county coroner, the hospital and autopsy reports of 91 unrestrained and 27 restrained fatally injured victims were reviewed. The hypothesis was that safety belts do not change patterns of injury in fatally injured victims. Patient data, seating position, and direction of impact were the same for both groups, while ejections occurred only in the unrestrained group (19.8%). Injury Severity Score (ISS), major injuries in AIS-85 categories for the Head, Thorax, Abdomen, and in AIS-85 Code 5 or 6 categories for the Head, Thorax, Abdomen were the same in unrestrained and restrained victims, except for the greater incidence of cerebral contusions in the unrestrained group (71% vs. 37%, p = 0.002). Cranial injuries were the most likely cause of death in nearly two thirds of the victims in both groups. The incidence of major head (other than cerebral contusion), thoracic, and abdominal injuries in unrestrained and restrained fatally injured victims was the same. This suggests that severe collisions with crushing, intrusion, or significant deceleration exceed the ability of restraints to prevent many fatal injuries.

Abdominal Injuries↗
PubMed1992

[The contribution of biomechanics to the safety of children inside motor vehicles].

Because laws mandating use of seat belts by motor vehicle drivers and front seat passengers have been passed throughout the developed world, it is becoming increasingly common to see parents protected from injuries whereas their children are abandoned to the tragic effects of chance and biomechanics. In France, the situation is especially critical. The law passed in 1975 requiring that all children use the back seat has reduced the risk of death and severe injury but nevertheless affords inadequate protection: each year, among children aged 0 to 10 years, several hundred are killed and nearly 10,000 injured in car accidents. This situation can be decisively improved, as shown by the figures in the United States and most European countries where use of child restraint devices (CRD) is mandatory. CRDs are designed to protect the child in the event of an accident by reducing the risk of injury due to ejection or projection against the inside of the vehicle: they play the same role as the seat belt for adults. France is the European country with the lowest rate of use of CRDs and the highest rate of child deaths due to motor vehicle occupant injuries. To improve this situation, regulations are being developed by the French government; use of appropriate CRDs will be mandatory for all children aged 0 to 10 years starting on January 1 st, 1992.

Accidents, Traffic↗
PubMed1998

Postural effects on hemodynamic response to interpersonal interaction.

Laboratory studies of stress-induced cardiovascular reactivity have been conducted predominantly with participants in a seated posture. This procedure may contribute to limited laboratory-field generalization of cardiovascular response. The present study examined hemodynamic adjustments underlying pressor responses, in addition to heart rate and systolic time intervals, during seated and standing role-played, interpersonal interaction in 60 young adults. Irrespective of gender or race, blood pressure responses to the seated and standing interactions were comparable. However, seated interactions yielded a significantly greater increase in heart rate, shortened preejection period and decreased stroke index as compared to standing. Alternatively, interacting while standing yielded a significantly increased left ventricular ejection time and total peripheral resistance in comparison to sitting. These results suggest that hemodynamic adjustments during stressful interpersonal interaction vary as a function of posture, with somewhat greater cardiac influences apparent while seated and a more pronounced vascular response while standing.

Adult↗
PubMed1989

Potential fatality reductions through eliminating occupant ejection from cars.

The percent of occupant fatalities preventable by eliminating ejection is calculated using Fatal Accident Reporting System (FARS) data for 1975 through 1986. The calculation requires estimates of two quantities. First, the fraction of all fatally injured occupants who were ejected; this is obtained directly from the FARS data. Second, the probability that an ejected occupant was killed compared to the probability that the occupant would have been killed in a similar crash in the absence of ejection; this quantity is estimated using the double pair comparison method, and its dependence on occupant age and sex and on car mass and model year is examined. High precision estimates of the reduction in fatalities that would result from eliminating ejection as functions of these same variables are thereby obtained. These estimates depend on assuming that whatever method is used to prevent ejection would cause the formerly ejected occupant to acquire the same fatality risk as a nonejected occupant in a similar crash; the study does not address how to prevent ejection. It is concluded that ejection elimination would decrease fatalities to unrestrained car occupants by 18 +/- 1%. The fatality reductions are independent of car seating position (19%, 19%, 17%, 16%, 19%, and 18% for drivers, middle front, right front, left rear, middle rear, and right rear passengers, respectively); they decrease with driver age, from 25% at age 18 years to 7% at 70 years; they decrease with increasing mass, but remained relatively independent of car model year since the early 1970s, being somewhat higher for earlier model years.

Accidents, Traffic↗
PubMed1979

[Elaboration of an in vivo model, in half life size, for aeronautical purposes].

Toxic effects of combustion products originating from plane cabin constituents are studied, in vivo, in Rats. The model associates an important combustion room, and an experience room containing eight revolving cages for Rats; these cages allow a remote control of the movements of the Rats which can be electrically stimulated and ejected. Such a device permits to study the incapacitance, i.e. the inability to move. For the combustion of a seat, without ventilation, incapacitation appears in 2 to 6 min. Biochemical screening demonstrates on increase of pCO2, carboxyhemoglobin and glycemia and a decrease of pO2.

Animals↗
PubMed1978

Theory and application of a three-dimensional model of the human spine.

A three-dimensional, discrete model of the human spine, torso, and head was developed for the purpose of evaluating mechanical response in pilot ejection. However, it was developed in sufficient generality to be applicable to other body response problems, such as occupant response in aircraft crash and arbitrary loads on the head-spine system. The anatomy is modelled by a collection of rigid bodies, which represent skeletal segments such as the vertebrae, pelvis, head, and ribs, interconnected by deformable elements, which represent ligaments, cargilagenous joints, viscera and connective tissues. Results are presented for several conditions: different rates of onset, ejection at angles, preejection alignment, and eccentric head loadings. It is shown that slow rates of onset and angling the seat reduce both the peak axial loads and bending moments. In the presence of eccentric head masses, such as helmet-mounted devices, the reflected flexural wave is shown to be the key injury mechanism.

Aircraft↗
PubMed1982

Motor vehicle occupant injuries to children in crash and noncrash events.

The mechanisms and severity of nonfatal injuries to children in crash and noncrash situations were compared: 82 children (15%) were involved in noncrash events and 466 (85%) were involved in crash events. Younger children (0 to 4 years of age) were more likely to be injured in a noncrash incident. The mechanism of injury was significantly different; 45% of the children injured in a noncrash event were ejected in contrast to 5% of the children injured in a crash event. Although more severe injuries were sustained in crashes, most of the children who were ejected in a noncrash event sustained at least moderate injuries. Use of restraint systems, door lock mechanisms, and appropriate passenger seating locations in the motor vehicle are three simple measures that could attenuate or eliminate noncrash injury.

Accidents, Traffic↗
PubMed1990

Recreational swimming in CHD patients and healthy control subjects in relation to left heart function.

We examined the influence on heart rate, blood pressure, lactate, glucose, and catecholamine levels of moderate recreational swimming at a mean time of 5.2 to 9 minutes with mean speed of 0.33 to 0.49 m/s in 25 CHD patients and 8 healthy control subjects. During swimming, changes in these exercise-related parameters were observed such as were only found in seated ergometry trials at levels above 100 to 175 W. We consider these changes tolerable for patients with mild left heart damage (n = 13; ejection fraction 54 +/- 7%; exercise capacity 2.1 +/- 0.4 W/kg). They may indicate overexertion in patients with marked damage to the left heart (n = 12; ejection fraction 44 +/- 5%; exercise capacity 1.3 +/- 0.4 W/kg). Six of the 12 patients with marked left heart damage stopped swimming before the planned time had elapsed for subjective (overexertion) or objective (arrhythmia) reasons.

Analysis of Variance↗