Abstract
Background
Motor vehicle collisions (MVCs) are the second leading cause of childhood mortality in the US, and child restraint systems (CRS) remain underutilized. We examine differences in demographics and clinical characteristics in pediatric patients presenting to the emergency department (ED) after MVCs with or without CRS.
Methods
We identified MVC trauma patients reported within the National Trauma Data Bank (NTDB) < 8 years of age and height/weight CRS-eligible. Bivariate descriptive analyses, interquartile range for continuous variables and a chi-square test of proportions tested differences of categorical variables of CRS strata. Sensitivity analysis was used in patients that were age appropriate for car and booster seats.
Results
In all patients, median age for those without CRS was older (6 years, IQR 4-7) than those with CRS (4 years, IQR 2-5, P < 0.0001). A lower proportion of Black patients had CRS compared to White (24.0% vs 32.6%, P < 0.0001). For those with CRS, the highest proportion were boosters (38.7%). Injury severity score (ISS) was higher in the non-CRS group (8, IQR 4-14) than CRS (5, IQR 2-11, P < 0.0001). A larger proportion of CRS patients were discharged home from ED (26.8% vs 18.5%). Racial disparities persisted in older patients, with fewer booster-eligible Black children in CRS (30.0% vs 17.9%, P < 0.001).
Conclusions
This study demonstrates that older and Black children were less likely to be in a CRS, and that those who were not in CRS were more severely injured. Our study serves as the foundation for research to mitigate disparities, and outreach related to CRS improvements.
Keywords
Introduction
Motor vehicle collisions (MVCs) are the second leading cause of childhood mortality in the United States. 1 When used properly, the National Highway Traffic Safety Administration (NHTSA) reports that child restraint systems (CRS) may reduce mortality by 54% in children ages 1-4 years up to 71% in infants. 2 Despite these findings, CRS remain underutilized or are improperly implemented. 3 A recent study revealed that up to 70% of pediatric patients younger than 13 years of age and involved in fatal MVCs were not using appropriate CRS. 4
Barriers to correct CRS use have been explored, and include socioeconomic factors, limited access to resources and lack of caregiver education. 5 Within the pediatric trauma patient population, however, the extent to which CRS are underutilized remains poorly delineated and understudied. 6 There is limited evidence that pertains to pediatric trauma patients and CRS with respect to their demographics, injury severity and clinical outcomes. 7 Understanding these discrepancies may highlight gaps necessary for educational outreach and trauma policy interventions.
In this study, we sought to examine differences in demographics and clinical characteristics among pediatric trauma patients who presented to the emergency department after MVCs with or without CRS, hypothesizing that proper CRS utilization yields improved clinical outcomes.
Methods
Study Setting
Two sites were included in this study to obtain survey data. The main site is a free-standing children’s hospital Emergency Department (ED), and Level I Trauma Center, that sees more than 110,000 patients annually. The secondary site is a children’s and women’s hospital with a Level II Pediatric Trauma center designation, that sees approximately 30,000 pediatric patients to the ED annually. Both study sites are located in the southwestern United States.
Participant Surveys
Patients aged 8 years and below who presented as trauma patients with a motor vehicle collision (MVC) mechanism of injury to two Emergency Departments in the study county were included. Patients over the height of four feet, nine inches or greater than 80 pounds were excluded. Trauma nurses and pediatrics residents conducted follow-up phone calls with families and provided education on how to obtain a replacement child restraint system, if indicated by National Highway Traffic and Safety Administration (NTHSA) guidelines. Participants were called between 14 and 21 days after the MVC and were called up to three times to obtain survey data. As this study involved minimal risk, informed consent was waived by the site IRB. All procedures were approved by the site’s IRB (#190781).
Data collected from participants included demographic data such as patient age, race, ethnicity, height, and weight, as well as questions that pertained to the MVC and CRS inspection afterward. Participants were asked if they checked the CRS, if cracks were identified, if the door near the CRS was damaged, airbag inflation, and if the car was drivable after the MVC. The participants were surveyed on information around their CRS including the type (infant, convertible, booster, etc.), CRS brand, where the CRS was located at the time of the MVC, if the child was forward or rear facing. Participants were then asked if they understood the NTHSA recommendations around CRS replacement as well as California state laws for children under two years or 40 pounds to be rear facing. Finally, participants were asked about replacement of the CRS after the MVC. If there was a sibling under the age of 8 years in the car, the participant repeated all questions for the sibling.
Population Data
Data on car seat use in cases of pediatric trauma in children 0-8 years old was extracted from the National Trauma Databank (NTDB). The National Trauma Data Bank Inclusion criteria was a motor vehicle collision e-code, age less than 9 years and the presence of data within the protective device field pertaining to car seat use status (car seat, booster, infant car seat, no car seat use). Missingness within other variables was allowed to prevent row-wise deletion of an observation that may contribute data in other meaningful ways.
Data Analysis
A descriptive table was produced to report upon the distribution of data within age-appropriate MVC trauma patients stratified by car seat use. Use of car seat, infant car seat, or booster met the criteria of car seat use regardless of if the car seat was age appropriate. Clinical and demographic characteristic distributions were reported within each category. Demographic characteristics included age, race, ethnicity, insurance status, and biological sex, height, and weight. Clinical characteristics included Injury severity score (ISS) at admission, facility pediatric status, bed size, hospital type (for profit, non-profit, and government). End points included length of stay, ICU length of stay, days on ventilator, ED discharge disposition, and hospital discharge disposition.
Bivariate inferential statistics were carried out to identify significant associations between car seat use and clinical and demographic characteristics. A Chi-square test of proportions was used to measure differences in the distribution of categorical data while a Welch’s t-test was used to assess the difference in distribution of continuous data, and a Wilcoxon rank sum test was used to measure differences in continuous data that was non-normally distributed. Shapiro’s test of normality was used to assess the distribution of all continuous data. Sensitivity analysis applying the same bivariate inferential statistics to patients that were age appropriate for booster (>3 & ≤8 years), and age appropriate for car seat (<4 years) were also conducted to assess confounding based upon an interaction between car seat selection and age. All statistical analysis was carried out using R statistical programming language 4.5.0. Age-based subgroup analyses were defined using thresholds aligned with national child passenger safety recommendations. The National Highway Traffic Safety Administration (NHTSA) recommends rear-facing CRS for children <2 years of age or until reaching size limits, forward-facing cat sears for approximately 2-4 years, and booster seats for children 4-8 years or until reaching 4 feet 9 inches in height. Give limitations in NTDB variables and lack of precise height and weight-based CRS matching, we defined children <4 years as car seat eligible, and children >3 years as booster eligible, to approximate these transitions.
Results
Study Cohort and Demographics
Distribution of Pediatric MVC Trauma Characteristics Stratified by Car Seat Use
Subset Analysis Children <4 Years
Distribution of Pediatric MVC Trauma Characteristics Stratified by Car Seat/Booster Subset to Age <4 Years
Subset Analysis Booster-Eligible Children >3 Years
Distribution of Pediatric MVC Trauma Characteristics Stratified by Car Seat/Booster Subset to Age >3 Years
Surveyed Population
Parent Guardian Response to Post-Accident Child Restraint Survey Stratified by Parent Reported Restraint Placement
Discussion
Our study demonstrates meaningful findings among this national cohort, where only one-third of pediatric patients involved in MVCs were documented as using CRS. This was confirmed through the study survey of participants after presentation to the ED for MVC. We found that lack of CRS was consistently associated with older age, Black race, higher ISS, more frequent admissions to the ICU, and fewer routine discharges from the ED. These findings support our hypothesis that appropriate use of CRS is associated with injuries of less severity, and highlights disparities in CRS use among children within the trauma population.
The National Highway Traffic Safety Administration (NHTSA) estimates that correct CRS use reduces the risk of fatal injury by 71% in infants and 54% in children 1-4 years old, emphasizing the critical role of CRS in preventing childhood mortality. 2 Similarly, a population-based analysis demonstrated that proper use of CRS is associated with lower MVC injury risk and fewer pediatric passenger fatalities. 8 Our study builds upon the established literature by specifically examining pediatric trauma patients who reach trauma centers following MVC, and establishing an association between appropriate CRS use and lower ISS, fewer admissions to the ICU and greater likelihood of routine discharge home from ED. A study produced by Durbin et al revealed that pediatric patients ages 4-7 in booster seats had 59% lower odds of MVC-related injury when compared to those using seat-belts alone, and did not experience injury to parts of the body typically affected by poorly secured seat-belts. 9 The findings of our study reinforce those presented by Durbin et al, suggesting that proper CRS both reduces the risk of injury in children and also attenuates the severity of injuries that inevitably occur.
CRS use was strongly associated with increasing age, weight, and height. These findings suggest that transitions out of CRS may occur prematurely as children grow, rather than strictly in accordance with safety recommendations. Children who were not properly using CRS were notably taller, heavier and older than those with CRS. This was particularly true of the booster-eligible children, 3 years of age or older. This pattern is consistent with national survey data that demonstrates that many children transition from CRS to adult seat-belts earlier than advisable. 10 The National Survey of the Use of Booster Seats (NSUBS) finds that only one-third of children ages 4-7 years old appropriately use booster seats, and that children who are unrestrained in MVC are overrepresented in fatalities. 11
Best practice recommendations emphasize a stepwise progression as children graduate from one CRS to the next, based primarily on height and weight, rather than age alone. 12 Our findings that booster-eligible children without CRS presented with higher ISS, more frequent admissions to the ICU and longer inpatient LOS supports the notion that premature graduation from CRS has tangible clinical consequences in pediatric trauma care.
We observed racial disparities related to CRS use in children, where Black pediatric patients were less likely to appropriately use CRS than their White counterparts, particularly among booster-age users. These findings augment broader disparities described in child passenger safety research produced by Macy et al, that reports Black children to be significantly less likely to be in age-appropriate CRS when compared to White children, despite adjustments made for socioeconomic factors and education sources. 13 Similarly, a study produced by Gunn et al found that Black children ages 4-10 years were more likely to be unstrained during MVC than White children. 14 National data and advocacy sources mirror the literature by highlighting child passenger fatalities and inappropriate CRS use with minoritized children, particularly in rural settings, underscoring a disproportionate burden. 15 These patterns reflect national systemic inequities, including disparities in affordable CRS access, educational safety resources, CRS installation help, and broad geographic determinants such as vehicle ownership. 15 Addressing these profound disparities in CRS access, education and use at the policy and system-level should target communities that are notably at highest risk.
Because trauma centers, especially those with pediatric trauma verification status, frequently encounter the patient population affected by CRS misuse during MVC, these centers represent a strategic setting for integrated intervention. The findings of our study support the combining of child passenger safety counseling and CRS access into clinical trauma workflows. Budziszewski et al established that Child Passenger Safet Technicians in pediatric trauma centers significantly improve correct CRS installation and safety knowledge. 7 The integration of similar models into the trauma discharge process, particularly among families of older pediatric patients or Black children identified as high-risk in this study, could aid in the reduction of disparities in CRS utilization and subsequent injuries.
Finally, our analysis underscores the role of data-driven quality improvement in pediatric trauma. NTDB-based studies such as ours may be used by verified trauma centers to identify gaps in CRS use in pediatric patients, for the purpose of highlighting disparities and targeting community outreach. Combining community-level interventions with trauma registry data could create actionable quality improvement projects related to CRS use, that translate into measurable reductions in variables like ISS and hospital resource utilization over time.
There are several limitations to this study. Our survey population was not powered to make causal claims and we were limited due to a small sample size. As a retrospective cohort analysis, we demonstrate associations but not causality between CRS use and injury outcomes. Confounders that are unmeasured or may not have been accounted for, including MVC speed, direction, seating position, or patient pre-existing medical conditions could influence both CRS effectiveness and injury outcomes. Additionally, the NTDB discrete variable fields do not discern between the nuances of correct CRS installation or age-appropriate use. NTDB does not allow for assessment of age or size appropriate CRS use, nor correct installation, limiting our ability to determine adherence to national or state-specific guidelines. The reporting and documentation of CRS use could be incomplete or inaccurate, subject to reporting bias in the trauma registry. Finally, the NTDB includes only pediatric patients who reached participating trauma centers. Pediatric patients who did not survive beyond the trauma scene, or who presented to institutions that are not represented in the NTDB, were not included in the study, potentially underestimating the true population burden of unrestrained MVC in children.
In conclusion, the findings of this study reinforce the critical protective role and size and age-appropriate CRS, and reveal significant disparities in CRS use within the pediatric trauma population. Trauma centers, legislators and community leadership could employ this data to create targeted, equity-focused child passenger safety interventions—expanding access to CRS, CRS education and booster-seat laws—to ensure that all children, regardless of age or race, benefit from proven, protective strategies.
Footnotes
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
Declaration of conflicting interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.