Abstract
PURPOSE: Car seats should be used to prevent injury or death in children during motor vehicle crashes. When used improperly or for unintended purposes, car seats can place children at risk for injury or death. The objective of this article is to describe patterns of hazardous use of car seats outside the car for infants (<1-year-olds) in the United States from 2003 to 2007.
METHODS: The National Electronic Injury Surveillance System of the US Consumer Product Safety Commission database was accessed to obtain information regarding car seat–related injuries treated in emergency departments from 2003 to 2007. Injuries sustained during motor vehicle crashes were excluded. Demographic data, type of injury, body location, disposition, injury circumstances, and other pertinent information were extracted and analyzed.
RESULTS: An estimated 43 562 car seat–related injuries were treated in emergency departments from 2003 to 2007. This national estimate was based on a weighted sample of 1898 infants. The average age of these infants was 4.07 ± 2.73 months, 62.4% of the injuries occurred in infants younger than 4 months, and 54.4% occurred in boys. Of these injuries, 49.1% occurred at home, 8.4% of the infants had to be hospitalized, and 84.3% of the infants suffered a head injury. The most common mechanisms of injury were infants falling from car seats, car seats falling from elevated surfaces, and car seats overturning on soft surfaces.
CONCLUSIONS: Injury-prevention efforts should be focused on eliminating hazardous use of car seats outside the car. Caregivers should be cautioned against the placement of car seats on elevated or soft surfaces.
The importance of car seats for the prevention of injury and fatality cannot be overemphasized. For example, in the first 4 years after enactment of the nation's first child-restraint law in Tennessee in 1978, the number of deaths related to traffic crashes among children younger than 4 years declined >50% in the state.1 Within the next 7 years, all 50 states passed child-restraint laws to protect infants and children during motor vehicle crashes. The National Highway Traffic Safety Administration (NHTSA) has estimated that 8959 children younger than 5 years were saved as a result of car seats or car safety belts between 1975 and 2008.2 Car seats have decreased the number of fatal injuries in infants in the United States by 71%.3
Car seats can lead to serious injuries and death if they are not used properly or for their intended purpose. Bull et al4 found that 76% of car seats were used incorrectly; however, there have been few reports that focused on injuries sustained as a result of hazardous use of car seats outside the car. In 1997 Pollack-Nelson5 used the National Electronic Injury Surveillance System (NEISS) database to examine patterns of injuries to infants younger than 6 months that were caused by car seats and infant carriers. Approximately 8700 injuries nationwide were reported. In the same study, review of the Consumer Product Safety Commission (CPSC) fatality records from 1990 through 1997 identified 3 fall-related deaths and at least 15 suffocation deaths, all caused by car seats or infant carriers overturning on soft surfaces. Desapriya et al6 examined the misuse of car seats with infants by using the Canadian Hospital Injury Reporting and Prevention Program (1997–2002). The mean age of their sample was 3.1 ± 2.8 months. Of 87 injuries, 86 were related to falls, and 43% of all falls were from elevated surfaces such as chairs, tables, and counters. The majority of injuries from the misuse of car seats occurred in the infant's home and resulted in superficial head injuries. In another retrospective study of 370 children younger than 2 years, Graham et al7 identified 27 patients who had injuries associated with the misuse of car seats. Thirteen of these patients were injured as a result of the misuse of a car seat in the car, and 14 infants (all younger than 1 year) were injured by falling from a car seat outside the car. Wickham and Abrahamson8 performed a prospective study that included all patients younger than 1 year who presented with a head injury to an institution in 1 year. Of 131 head-injury cases, 17 were associated with either a car seat or bouncy chair. Thirteen of these 17 injuries were the result of a fall from an elevated surface.
The purpose of our study was to provide estimates regarding the number and pattern of injuries sustained from the hazardous use of car seats outside the car in the United States from 2003 to 2007. The identification of these patterns should help to raise awareness and prevent these injuries in the future. This study was approved by the institutional review board at Cincinnati Children's Hospital Medical Center.
MATERIALS AND METHODS
The NEISS is a database through which the CPSC records consumer product–related injuries treated in a nationally representative sample of emergency departments (EDs) throughout the United States. Data detailing injuries related to car seats (product code 1519) for a 5-year period (2003–2007) were extracted. Data collection was limited to those for infants younger than 12 months, and injuries sustained in motor vehicle crashes were excluded. Injuries from infant carriers, bouncy chairs, or other related products were also excluded. The CPSC does not analyze the crashworthiness of the car seats; hence, these estimates were excluded.
The parameters included were age, gender, race, location at which the injury occurred, body part injured, injury diagnosis, and injury disposition. All the parameters were further subdivided for ease of data entry and analysis. Age was divided into 3 groups: 0 to 4, 5 to 8, and 9 to 12 months. Race was categorized as white, black, Hispanic, Asian, Native American, or unknown/not stated. The location at which the injury occurred was categorized as home (including garage, yard, driveway, farm), away from home (including school, playground, public property), or others/not stated. Body-part injuries were categorized as head/neck, upper extremity (including shoulder), lower extremity, pelvis/trunk, all of body, or others/not stated. Injury diagnosis was categorized as internal organ injury (including head injury and concussion), soft tissue injury (including lacerations, abrasions, and sprains), fractures, dislocations, or others/not stated. Disposition was categorized as inpatient, outpatient, fatality, or others/not stated. The injury narrative from the NEISS database was further categorized according to mechanism of injury, surface and height of fall (including the surface from and on to which the infant/car seat fell), and use of restraint. The mechanism of injury was categorized as infants falling from car seats, car seats falling from elevated surfaces, car seats overturning, or others/not stated. If another consumer product besides a car seat was involved in the injury (eg, car seat falling from a shopping cart), the second product code was also recorded.
Data were analyzed by using SAS 9.2 software (SAS Institute, Inc, Cary, NC). National estimates are reported with 95% confidence intervals (CIs) and were calculated by using sample weights from the NEISS database. Discrete data are reported as percentages, rounded to the first decimal. The odds of injury were calculated by using logistic regression analysis. χ2 tests for goodness of fit were conducted. All P values of <.05 were considered statistically significant. Adjustments for multiple comparisons were not made.
RESULTS
On the basis of the sample count of 1898, there were an estimated 43 562 car seat–related injuries treated in hospital EDs in the United States during a 5-year period from 2003 through 2007, with an average annual estimate of 8712 injuries. The estimated annual number of injuries with 95% CIs is depicted in Fig 1. The average age of the infants was 4.07 ± 2.73 months. The demographic data and injury parameters assessed are listed in Table 1.
The NEISS is a sample of hospitals and not a census; hence, the annual estimates have associated variability. The 95% CIs around the estimate were calculated by using the historical estimate and coefficient of variation provided by the NEISS. The annual estimates were steady over the 5-year study period.
Demographics
The injury-narrative analysis revealed that 85% of the injuries were related to falls: 64.8% were caused by infants falling out of car seats, 14.6% were caused by car seats falling from elevated surfaces, and 5.6% were caused by falls (not specified further) (Fig 2). For the 64.8% of the infants who fell out of their car seats, their fall was either the result of being carried or being placed on an elevated surface in their car seat. It was assumed that these infants were unrestrained in their seats. Common surfaces from which infants/car seats fell included shopping carts (8.1%), tables (6.3%), and counters (3.8%). The common surfaces onto which the infant/car seat fell included floors (including carpet, tile, and hardwood) (27.3%), concrete/pavement (including sidewalks and parking lots) (10.5%), and the ground (including grass and gravel) (3.7%). The height of the fall was mentioned in only 9.9% of cases; the mean height was 29.8 ± 11.15 in. Data regarding the use of restraints was available for only 16.8% of the patients (11.8% were unrestrained, and 4.9% were restrained). In 59.4% of the injuries another consumer product was involved; the most common products were floors or flooring materials (code 1807), tables (code 4057), and shopping carts (code 1679). There were 3 deaths reported during this 5-year period. Although each death was related to car seat use, further details concerning mechanism and circumstances were not available from this database, so they were not analyzed further.
Injuries that resulted from a fall were the most common mechanism of car seat–related injuries to infants.
Head/neck injuries constituted the majority of injuries for the sample; however, on the basis of logistic regression, younger infants were more likely to have a head/neck injury (P = .0015). The odds of having a head/neck injury were twice as likely (95% CI: 1.394–3.067) for infants aged 0 to 4 months compared with infants aged 9 to 12 months, and 5- to 8-month-old infants were 1.8 times more likely (95% CI: 1.176–2.749) than infants aged 9 to 12 months to have a head/neck injury. There was no statistically significant difference between the 0- to 4-month-old and the 5- to 8-month-old groups (95% CI: 0.870–1.521). On the basis of χ2 goodness-of-fit testing, there was a greater proportion of injury among white infants compared with black (P < .0001) and Hispanic (P < .0001) infants. There was also a greater proportion of injury among black infants compared with Hispanic infants (P = .0007). On the basis of logistic regression, the odds of being treated as an inpatient were 2.3 times higher for infants aged 0 to 4 months than for infants aged 5 to 8 months. The NEISS database provides data on the number of injuries, but the number of exposures (eg, time spent in car seat outside the car or frequency of hazardous use of car seats) is not known, so we could not calculate true injury risk rates. Thus, although there was a greater proportion of injury among white compared with black and Hispanic infants, true injury risk rates could not be calculated.
DISCUSSION
Data for this study were obtained for a 5-year period from 2003 to 2007. There was an annual estimated 8712 injuries reported. This number remained steady over the study period (Fig 1) and also approximates the 8700 injuries reported in a study conducted in 1997. The data shown here cannot strictly be compared with those from the 1997 study, because the earlier study included data from infant carriers as well as car seats.5 Similar to other researchers, we found that infants aged 0 to 4 months were in the most common age group injured, probably because of their motor skills being less developed compared with older infants. They spend most of the time lying down compared with older infants, who can sit and crawl and are more advanced in motor development. This fact could give a false sense of security to parents, who might think that their infant cannot move much and deduce that it should be safe to keep the infant in a car seat. The increased number of injuries in the 0- to 4-month age group could also be the result of the infants being in a car seat more often relative to older infants.
Injuries are a leading cause of death and morbidity in the first year of life. Of an estimated 328 500 infant (<12 months old) injuries treated in hospital EDs between 2001 and 2004, more than half were the result of a fall.9 In 2006 alone, there were 1147 infant fatalities caused by unintentional injuries in the United States.10 An infant's risk of injury is influenced by surrounding environment, developmental milestones, parental knowledge, skills, and abilities, and consumer products.11 It is a common parental misconception that infants cannot move, wiggle, or turn while they are in a car seat, causing either the infant or the car seat to fall from an elevated surface or overturn. The high rate of car seats falling from elevated surfaces indicates that parents consider this to be a safe practice. In a prospective study, only 1 of 13 caregivers was aware that there was a chance of injury to their infant caused by the fall of a car seat or bouncy chair when placed on an elevated surface.8
There have been multiple reports of infants, left unattended, falling from elevated surfaces. For instance, a 7-month-old infant was placed on an engaged washing machine in a car seat as recommended by a physician to console the child. The infant fell and sustained an epidural hematoma that required surgical intervention.12 Graham et al7 reported on 5 cases in which infants sustained head/neck injuries as a result of the fall of a car seat from the roof or trunk of a car. The American Academy of Pediatrics (AAP) released a statement in which it counseled and cautioned against the placement of car seats on shopping carts.13 Placement of infants in car seats on an engaged washing machine, car roof or trunk, shopping cart, or other similar elevated surface should be strictly discouraged, and parents should be counseled and educated about these hazards.
A recent report from the AAP stated that “The duration of time the infant is seated in a car safety seat should be minimized. Parents should be advised that car seats should be used only for travel.”14 The AAP also counsels that car seats should not be used for positioning outside the vehicle.15 In some situations, parents may be compelled to keep infants in car seats on elevated surfaces to protect them from pets or other siblings5 or to keep the infant at eye level for better rapport. It would be safer to transfer the child from the car seat to a crib or play area; however, if the car seat must be placed on an elevated surface, parents need to make sure that the infant is restrained, the car seat is not on the edge of the elevated surface, the surface is firm, and constant supervision is maintained to prevent injury.
The AAP also issued a statement in which it counseled parents on car seat selection and installation, child placement, and safety to prevent injuries to children during motor vehicle crashes.16,17 Similarly, the NHTSA has provided parents a Web-based system that allows them to evaluate the ease of use of certain car seat features.18 Aside from the AAP and NHTSA, parents rely on health professionals for up-to-date, accurate information on child health, injury prevention, and child safety. Desapriya et al6 stressed the importance of injury-prevention education during routine health maintenance visits to primary care physicians. Prenatal and postnatal visits represent time points at which educational material and knowledge about the safety of car seats, and potential injury from their hazardous use, could be imparted. Another setting that represents a teaching opportunity is during ED visits when injured infants are brought for care.19
Media campaigns could be another injury-prevention tool and might be far more effective than individual counseling,19 especially when the campaign is accompanied by changes in product design or enactment of new laws to regulate product use. Educating the public via the media can reach more families at a single time, thus raising awareness about injury prevention more effectively. The story in USA Today in October 200920 about the nature, magnitude, causes, and consequences of hazardous car seat use outside the car was the first media report focused on raising public awareness to prevent such injuries. Similarly, legislative advocacy is an activity with which few physicians are involved, yet it can affect the lives of many children at once.19 In areas where health care providers see numerous injuries related to the hazardous use of car seats, they should participate in legislative endeavors and public-awareness efforts to frame steps for primary injury prevention in their community.
Car seat manufacturers have an obligation for and vital role in the prevention of injuries from the hazardous use of their products. First, car seat instruction manuals should contain information regarding potential hazardous use and related injury information. Wickham and Abrahamson8 recommended pictorial warnings to illustrate the potential hazardous uses of car seats. Pollack-Nelson5 recommended warning notices to be placed in a way that obstruct or interfere with the initial use of car seat (eg, a large tear-off sheet attached to the product strap). A permanent warning label that identifies patterns of hazardous use should be placed on car seats in noticeable areas. In addition, manufacturers could improve design features of car seats to enable caregivers to safely use car seats for purposes other than transport. Car seats could be equipped with a stable base with brakes, blocks, or stops that would prevent them from rocking or sliding on slippery surfaces. The curved seat frame, typical in modular car seat systems, should undergo engineering analysis to address issues such as center of gravity.5 The potential of a car seat to overturn should be analyzed, and improvements, such as adding side supports, should be made in the current car seat design. In the absence of any decrease in the annual injury estimates over the 5-year study period compared with injury estimates from 1997,5 the CPSC and manufacturers should step up their efforts and adopt voluntary standards in the design of car seats to obtain a meaningful reduction of such injuries.
There are several limitations of this study. First, the NEISS database only includes injuries treated in hospital EDs and excludes those injuries treated at home, in physicians' offices, or in outpatient clinics. In addition, fatalities are not well documented, so information regarding the number and circumstances of fatalities from car seats could not be reliably obtained. Second, narratives in some cases provided incomplete or inconsistent information about the injury event. For example, information about the height of falls was available only in 9.9% of the cases, and information about the use of restraints was only available in 16.8% of the cases. Also, caregivers may not have provided all or true information because of fear of legal implications or to avoid embarrassment. Third, the database provides only national estimates (not state or local estimates), so specific regional practices and variations could not be ascertained. Fourth, all car seats have a common product code, so we were not able to ascertain if there were certain types of car seats that were more prone to be used in a hazardous manner or were associated with increased rates of injury. In the future, it may be worthwhile to collect more specific information about car seats (eg, make, type, and model) to help identify if a specific type of car seat is more prone to cause injury. Finally, we were unable to assess other reported adverse events associated with the use of car seats, such as cardiorespiratory events, gastroesophageal reflux, plagiocephaly, or seat belt–related strangulation, because of the methodology of our study.14,21
ACKNOWLEDGMENTS
We thank Shelia Salisbury, PhD, and Beverly Schnell, PhD, for assistance with the statistical analyses for this project.
Footnotes
- Accepted April 20, 2010.
- Address correspondence to Shital N. Parikh, MD, Division of Orthopaedic Surgery, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave, ML 2017, Cincinnati, OH 45229. E-mail: shital.parikh{at}cchmc.org
FINANCIAL DISCLOSURE: The authors have indicated they have no financial relationships relevant to this article to disclose.
- NHTSA =
- National Highway Traffic Safety Administration •
- NEISS =
- National Electronic Injury Surveillance System •
- CPSC =
- Consumer Product Safety Commission •
- ED =
- emergency department •
- CI =
- confidence interval •
- AAP =
- American Academy of Pediatrics
REFERENCES
- Copyright © 2010 by the American Academy of Pediatrics
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