Biomedical subjects

S W Rouhana

Publications and source records attributed to S W Rouhana.

7 recordsLinked to original sources

PubMed2003

Investigation into the noise associated with airbag deployment: part III - sound pressure level and auditory risk as a function of inflatable device.

Several criteria for assessing noise-induced hearing loss from automotive inflatable devices, such as airbags, were proposed in the past. However, their development was based on epidemiological studies of steady state noise and not impulsive noise. More recently, the US Army Research Laboratory (ARL) developed and validated a mathematical model of the ear, which may be used to assess noise induced hearing loss from impulsive noise sources. Previous studies have contributed to understanding the effects of impulse noise on occupants, but were performed on first generation frontal airbags and did not provide information on airbag and occupant safety systems in today's fleet of vehicles. This study presents the results of a parametric investigation of current inflatable devices across a variety of vehicles and considers the size and seating location of the occupant in vehicles of varying volume. In addition, the study considers advanced airbag technologies such as dual stage frontal airbags, side airbags, inflatable curtains, and seat belt pretensioners.

Adolescent↗

PubMed2003

Lower extremity injuries in lateral impact: a retrospective study.

ABSTRACT A retrospective analysis of the NASS/CDS database from 1993 to 2000 was used to investigate lower extremity injury in lateral impact. The analysis includes the study of the injury patterns, crash characteristics and the interactions between the occupant and the vehicle interior, including injuries to the farside occupants. The findings include significantly different injury patterns for the nearside and farside impacts. In particular, while the proportion of pelvis/hip injuries, with respect to AIS2 and AIS3 lower extremity skeletal injuries and 2-4 and 10-8 o'clock side impacts, was higher in nearside (70.4%) than farside (38.3%), the opposite trend was observed for the thigh (2.8% vs 4.5%), knee (6.2% vs 16.7%), leg (10.1% vs 19.5%) and foot/ankle (5.6% vs 14.7) injuries. Analysis of the PDOF suggested that a large proportion the impacts occurred obliquely, at approximately 10 and 2 o'clock, with a rearward component of force. It is hoped that the findings of the current study can help to investigate injury mechanisms.

Abbreviated Injury Scale↗

PubMed1999

Hearing loss and automobile airbag deployments.

In an on-going research program, on the causation of injuries in motor vehicle accidents, at the University of Michigan Transportation Research Institute, crashes with airbags have been, and are continuing to be, investigated. In order to determine the occurrence, if any, of 'hearing problems' associated with airbag deployments, drivers and passengers who had been involved in 'airbag' automobile crashes were interviewed by telephone. From the crashes investigated, 225 attempts were made to contact drivers who were exposed to airbag deployments. From these telephone interviews, contacts were made with 177 car occupants. Only three reported that they had experienced any type of hearing-related problems subsequent to their crash. One other case is reported of a driver who had pre-crash hearing loss. It appears that permanent hearing deficit due to airbag deployment, both in cars with the steering wheel airbag alone, and in those with a passenger side airbag, is an infrequent event (1.7%) from the data of this study.

Accidents, Traffic↗

PubMed1995

Physical and chemical characterization of airbag effluents.

OBJECTIVE: This paper describes a study aimed at characterizing the exposure to physical and chemical by-products from the deployment of airbag restraint systems. DESIGN, MATERIALS AND METHODS: Specifically, the levels of particulates and the composition of gases and bag fabric speed were measured in the passenger compartment following deployment of either a driver's side or driver's side/passenger's side airbag system. MEASUREMENTS: A Fourier transform infrared analyzer (FTIR) and chemiluminescence analyzers were used for gas analysis, a cascade impactor and gravimetric filter measurements for aerosol determination and high-speed films to determine fabric speed. MAIN RESULTS AND CONCLUSIONS: The measured gases were found to be within the recommended guidelines for human exposures, but no guidelines exist for particle exposures of this magnitude (150-220 mg/m3) but short duration. High-speed films were also taken of the deployments to obtain an estimate of the fabric speed as it leaves the module. The maximum average speed for both types of airbag was approximately 100 mph and in both cases average speeds ranged from lows near 50 mph to highs of over 200 mph.

Air↗

PubMed1989

Blunt rupture of the diaphragm: mechanism, diagnosis, and treatment.

In the absence of respiratory distress and massive visceral herniation, the diagnosis of blunt diaphragmatic disruption can be difficult. This is particularly true for diaphragmatic injuries confined to the right hemidiaphragm. Because diagnostic delay and strangulation are associated with notable increases in mortality and morbidity, it is important to identify the injury as early as possible. Victims of lateral impact motor vehicle collisions are more likely to experience rupture of the diaphragm than victims of frontal collisions. Occupants exposed to left lateral impacts are at greatest risk. The side of diaphragmatic rupture correlates with the direction of impact. The right hemidiaphragm is more resistant to rupture. Deformation shear is a more plausible mechanism for diaphragmatic rupture after lateral impacts. Knowledge of the mechanisms that produce this injury combined with information regarding the victim's seat position and direction of the impacting force should lead to a high index of clinical suspicion for diaphragmatic rupture. Chest radiography and diagnostic peritoneal lavage will establish the correct diagnosis in almost 90% of the patients with acute diaphragmatic disruption. Additional diagnostic studies are reserved for the remaining 10% of patients. Due to the pressure differential between abdomen and thorax, the natural history of these injuries is one of enlargement, and none can be expected to heal spontaneously. Once the diagnosis has been established, the treatment of every diaphragmatic disruption is surgical repair.

Accidents, Traffic↗

PubMed1985

Influence of velocity and forced compression on the severity of abdominal injury in blunt, nonpenetrating lateral impact.

Lateral impacts of automobiles frequently result in abdominal injury to the occupants. While there have been important advances in the clinical management of this lateral impact trauma, the abdominal tolerance to injury from lateral impacts remains uncertain. The present report describes a series of 117 experiments in which the effect of changing the impact velocity and the forced abdominal compression upon the abdominal injuries sustained was monitored. The impact velocity was varied from 3 to 15 m/s, and the abdominal compression was varied from 10 to 50%. Serious injuries (AIS greater than or equal to 3) occurred in the following proportions of the total number of serious injuries: renal (54%), hepatic (44%), and splenic (1%). Impact side was a significant factor in hepatic and splenic tolerance, but not in renal tolerance. An abdominal injury criterion (AIC) is proposed which is a function of the impact velocity times the forced abdominal compression, but more work is necessary before it can be applied to human beings.

Abdominal Injuries↗

PubMed1982

Fluid flow in bone in vitro.

Recent dielectric measurements suggest that the electromechanical effect in wet (fluid saturated) bone is not due to a piezoelectric effect. This would imply that the electromechanical effect observed in wet bone is due to a streaming potential and is therefore dependent on fluid flow in stressed bone. A model for fluid flow in bone in vitro is presented. This model predicts a rapid decay (of the order of a millisecond or less) for the fluid flow in Haversian systems. The implications of this result for the interpretation of the electromechanical effect in wet bone are discussed.

Biomechanical Phenomena↗