Factors associated with car seat test failure in late preterm infants: A retrospective chart review.

Smith, Ryan W; Mohamed, Adel; Young, Jennifer; Jefferies, Ann; Shah, Vibhuti

BACKGROUND Professional organizations recommend car seat testing of preterm infants before discharge from hospital. Late preterm infants (LPIs, 34(0/7) to 36(6/7) weeks' gestational age) are at the greatest risk for failure, despite often being well. OBJECTIVE To determine the incidence of car seat testing failure in LPIs and associative factors. METHODS A retrospective chart review was performed of inborn LPIs admitted to all levels of newborn care between July 1, 2012 and June 30, 2013. Data collected included maternal demographics, labour and delivery history, and neonatal course. Data were analyzed using backward logistic regression. RESULTS A total of 511 charts were reviewed and 367 LPIs were eligible for inclusion. Of the 313 LPIs tested (mean [± SD] gestational age 36 weeks ±6 days and birth weight 2614±405 g), 80 (26%) failed (95% CI 21% to 31%). Most failed due to desaturations (≥2) of <88% for ≥10 s (n=33 [41%]). Multiple gestation was associated with failure (adjusted OR 2.45 [95% CI 1.44 to 4.18]; P=0.001), and there was a trend toward statistical significance for the variable postnatal age (0.996 [95% CI 0.99 to 1.00]; P=0.05). Infants who passed their car seat test had higher postnatal ages than those who failed (mean difference 39.4 h [95% CI 12.7 h to 66.0 h]; P=0.004). CONCLUSION Twenty-six percent of LPIs failed car seat testing. Ideally, infants should be tested after an appropriate transitional period. The authors identified factors that may be important in designing future, prospective studies in this area. Future research should evaluate the clinical significance of car seat testing and resource utilization.