Recent Trends in Infant Car Seat Tolerance Screening Failure Within a Large Health Care System, 2014-2018

To describe temporal trends in car seat tolerance screening (CSTS) failure within a large hospital system (2014-2018).

We conducted a retrospective cohort study using electronic medical record data for infants who underwent a CSTS. Our primary outcome measure was the CSTS failure rate. Covariates included year, CSTS location (well nursery or NICU), gestational age (GA), race, sex, birth weight, CSTS date, and age at CSTS. Associations of covariates with CSTS failure were examined by using χ² tests, t tests, analysis of variance, and Wilcoxon rank tests. Multivariable logistic regression was used to determine the adjusted odds of CSTS failure.

Of 4849 infants tested, the failure rate was 8.1% (n = 394). Most CSTS occurred in the well nursery (79.5%) and involved late preterm (55.2%) or term infants (23.7%). In bivariate analyses, year, unit location, higher birth weight, younger chronological age at testing, and higher GA were positively associated with CSTS failure (P < .05). After stratification by CSTS location, the CSTS failure rate rose in the well nursery but remained stable in the NICU, and use of screening rose among term infants. In the adjusted model, year, GA, and corrected gestational age at CSTS were associated with failure. Each subsequent year was associated with a 19% increase in odds of CSTS failure (P < .001).

We found a higher rate of CSTS failure in the well nursery compared with the NICU, and the difference in failure rates increased over time. Improved understanding of infants at the highest risk of CSTS failure could impact routine screening guidelines.