Anticipatory Guidance About Child Safety Seat Misuse: Title and subTitle BreakLessons From Safety Seat "Checkups" FREE

COUNSELING parents about injury prevention is a well-accepted component of pediatric care. While physician-dispensed advice can have a powerful influence on parents, specific advice is more effective than general advice.¹ Motor vehicle crashes are the leading cause of death among US children older than 1 year, and many of these deaths could have been prevented by the proper use of child safety seats.² In a recent study injury prevention experts were polled about the priorities for discussion of injury prevention issues at pediatric preventive care visits. All of those polled agreed that motor vehicle occupant protection should receive the highest priority.³

Studies of child safety seat use have shown both that there is far from universal use of these seats and that these seats are frequently used improperly.^{4 - 9} Improper use of child safety seats may decrease the effectiveness of these seats in preventing injuries or death.^{4 ,10} One factor that probably contributes to improper use of safety seats is that proper installation and use of safety seats is complicated, and that this differs for different models of seats, different vehicle safety belt systems, and different seating arrangements.^{7 ,11} Child safety seat "checkups," in which an expert in safety seat use examines whether a particular seat is appropriate for a specific child, how that seat is attached in the vehicle, and how the child is secured in the seat, may be one way to promote proper safety seat use.

In this article we describe what we found during a series of such checkups. Our aims were to quantify the frequency of improper child safety seat use and to identify the most common mistakes in safety seat use, so that priorities for anticipatory guidance about misuse could be identified. The high frequency of improper use in our study strongly suggests the need to counsel parents about the proper use of child safety seats, and the identification of common mistakes in safety seat use makes it possible for pediatricians to economically include specific suggestions about proper safety seat use in discussions with parents.

Between January 1, 1998, and December 31, 1998, the Louisiana SAFE KIDS Coalition helped organize a series of child safety seat checkups at 11 locations in southern Louisiana. These locations included automobile dealerships, parenting centers, a community park, and a shopping mall. Parents were recruited for the checkups through publicity in the local media and by sponsoring businesses. At the checkups staff trained in child safety seat use by the National Highway Traffic Safety Administration examined each safety seat to see if it had been recalled by the manufacturer, was appropriate for the height and weight of the child, was properly installed in the vehicle, and if the child was properly secured in the seat. Characteristics examined to determine if a safety seat was properly installed are listed in Table 1. If any deficiencies in safety seat use were found, parents were instructed on how to correct them.

Because all types of safety seat misuse are not equally dangerous, we categorized each instance of misuse according to the degree to which it compromised the efficacy of the seat to prevent injuries. To do so we used a child safety seat misuse index developed by Margolis et al,⁷ based on a review of the literature, discussions with experts in safety seat design, and the clinical judgment of the authors. This index has 3 levels of seat misuse: minor misuse or correct use, partial misuse, and extensive misuse.

Data were analyzed using a computer program (Epi Info, Version 6; Centers for Disease Control, Atlanta, Ga).

Three hundred seventeen child safety seats were checked in 4 southern Louisiana cities (Greater New Orleans, 200/317 [63%]; Baton Rouge, 92/317 [29%]; Lake Charles; and Hammond, 25/317 [8%]). Of the 316 seats for which the type of vehicle was recorded, 177 (56%) were installed in cars, 69 (22%) were installed in vans, 58 (18%) were installed in sport utility vehicles, and 12 (4%) were installed in trucks.

Of the 317 seats checked, 162 (51%) were forward-facing convertible or toddler seats, 104 (33%) were rear-facing convertible or infant seats, and 51 (16%) were booster seats (35 belt-positioning booster seats and 16 shield booster seats). Thirteen seats that had been recalled by their respective manufacturers were identified. Because the number of specific types of booster seats examined was small, the remainder of this article describes errors noted for forward- and rear-facing convertible, infant or toddler seats only. Seats were considered to be installed correctly only if all aspects of installation, as specified in Table 1, were correct.

Of the 266 forward- and rear-facing seats checked, 250 (94%) were installed incorrectly. Forward- and rear-facing seats were equally likely to be incorrectly used. The 3 most frequently found problems were seat not belted into the vehicle tightly (142 [88%] of forward-facing seats and 84 [81%] of rear-facing seats), seat harness straps not snug (70 [43%] of forward-facing seats and 49 [47%] of rear-facing seats, and harness retainer clip not at armpit level (55 [34%] of forward-facing seats and 38 [37%] of rear-facing seats) (Figure 1). Using the child safety seat misuse index, 61 (23%) of the seats had minor misuse or were correctly used, 107 (40%) of the seats were partially misused, and 98 (37%) of the seats were extensively misused.

This article documents frequent misuse of forward- and rear-facing child safety seats. Overall, 94% of the child safety seats were used incorrectly and 37% of the safety seats were misused in a way that had the potential to extensively compromise the seat's ability to prevent injury. Although frequent misuse of child safety seats has been documented in the past,^{4 - 9} the data in this article call attention to the persistence of this problem despite its recognition. This article also documents that the 3 most frequent errors in use were seat not belted into the vehicle tightly, seat harness straps not snug, and harness retainer clip not at armpit level.

Anecdotal and biomechanical data suggest that the 3 most common patterns of misuse identified in this study may substantially decrease the effectiveness of child safety seats.^{4 ,10} In simulated crashes in which the child safety seat is not belted in tightly, hyperflexion of the neck with forward displacement of the head and stress forces to the head and chest that exceed critical safety values have been documented.¹⁰ A child restrained too loosely is at risk for femur fractures due to "submarining" of the child such that the child's lower extremity hits the seat back in front of him or her. Children restrained too loosely are also at risk of injuries from overextension of the neck.^{10 ,12} When the buckle of the safety seat is positioned too high, it can slide up into the child's neck causing cervical hyperextension and causing the head to hit against the buckle, leading to serious head injuries.¹⁰ When the buckle is positioned too low, occult abdominal injuries can occur.⁴

One limitation of this study is that, because the study subjects were self-selected, the prevalence and pattern of misuse may not be representative of the population as a whole. With regard to overestimates of prevalence, other studies using samples designed to be more representative of the population as a whole have documented that child safety seat misuse is widespread, with prevalences of misuse ranging from 60% to 80%.^{4 - 5 ,7 ,9 ,13 - 14} Although the prevalence of safety seat misuse in these studies is slightly lower than what we found in our study (94%), comparison is difficult because of differing definitions of misuse and because these studies were conducted in different geographic areas. With regard to bias in the relative frequency of different types of misuse which we detected, one might hypothesize that parents with more obvious errors in child safety seat use might be more likely to self-refer to a safety seat checkup and, therefore, that more obvious errors would be overrepresented in our sample. However, although data on why parents came to our checkups was not formally collected, anecdotal reports suggest that the overwhelming majority of parents thought that their child safety seats were being used correctly and were expecting to receive only reassurance at the checkup (K.C., oral communication, February 9, 1999).

At least one contributing factor to child safety seat misuse is the complexity of attaching and using different safety seats properly in different models of different types of vehicles.^{11 ,15} Different models of safety seats attach differently, and different types and models of vehicles require different attachment mechanisms. The recognition of this problem has led to the adoption of a federal rule requiring all models of vehicles and all models of seats to have a universal and simplified mechanism for attachment.¹⁵ Although this rule will be in full force as of September 1, 2002, many vehicles and child safety seats with earlier manufacture dates will still be used for many years to come. Thus, it appears that child safety seat misuse is likely to be a problem that will not be solved immediately with changes in technology.¹¹

The high frequency of certain types of child safety seat misuse suggests that pediatricians should include counseling on these errors in anticipatory guidance that they give to parents. Spoken advice is thought to be a powerful way to help parents acquire new knowledge, and advice that is concrete and specific is thought to be especially effective.¹ Others have suggested that health care providers (ie, physician, nurses, or nurse practitioner) counsel parents about proper safety seat use.^{4 ,11} Based on our data about the most frequent errors in safety seat use we suggest that pediatricians counsel parents specifically to at least make sure that their child safety seats are tightly belted in (so that they do not move more than 1 in when firmly tugged on), that the harnesses are snug on their children, and that the harness retainer clips are positioned at armpit level. The time available during the typical pediatric visit for anticipatory guidance is limited. However, the importance of motor vehicle crash injuries to children, the effectiveness of child safety seats in preventing those injuries, and the limited number of extremely frequent errors in seat use suggest that guidance about child safety seat misuse could be incorporated into pediatric anticipatory guidance economically.

Parental information handouts also have been shown to be effective, and can be a useful reinforcement to spoken advice from the pediatrician.¹ The American Academy of Pediatrics, Elk Grove Village, Ill, together with Allstate Insurance Company has developed a brochure titled, "1-Minute Car Seat Safety Check-up: All Kids Ride Safe Brochure," for distribution to parents.¹⁶ This handout tackles many of the common child safety seat misuse issues noted in this study. In many areas child safety seat checkups, like those described in this article, are also available. Staff trained to check for proper seat use are available in many areas. Pediatricians may want to investigate the possibility of sponsoring such checkups, which not only can promote proper seat use, but also be a useful marketing tool for a pediatric practice or hospital.

In summary, this article documented several frequent errors in child safety seat use that are likely to substantially reduce the ability of those seats to protect children from the most common cause of death and substantial morbidity in young children. These data suggest that pediatricians should counsel parents specifically about these frequent errors in child safety seat use as part of the routing anticipatory guidance offered during well-child visits.

Accepted for publication November 12, 1999.

We thank Kenneth D. Rosenberg, MD, MPH, of the Oregon Health Division, Portland, for his editorial input and encouragement.

Reprints: Melvin Kohn, MD, MPH, Oregon Health Division, 800 NE Oregon St, Suite 772, Portland, OR 97212.