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

Abstract

B oth the Canadian Paediatric Society and the AmericanAcademy of Pediatrics recommend a "car seat challenge" for preterm infants (<37 weeks' gestational age [GA]) before discharge from the hospital (1,2). Additional criteria often include full-term infants with significant neurological or cardiorespiratory disorders (3-5). Testing has been recommended in these populations following studies performed in the 1980s, which found that preterm neonates experienced periods of oxygen desaturation when placed in a semi-upright position, which persisted but improved once placed supine (6,7). In 1993, Bass et al (8) collected data over a 15-month period following implementation of a 90 min car seat test for all preterm infants in their level 2 nursery. Sixteen of 87 (18.4%) infants had abnormal results (the majority of which were desaturations <89%). This sample included seven of 33 (21.2%) infants of 36 weeks' GA (8). A more recent study identified that late preterm infants (LPIs, infants 34 0/7 to 36 6/7 weeks' GA) have higher failure rates than preterm infants with lower GAs (9). The hypothesis for increased failure rates is that LPIs are tested at younger postnatal ages, allowing less time for physiological maturation. Second, infants born more preterm are usually admitted to the neonatal intensive care unit (NICU), undergo prolonged periods of monitoring, and are tested when stable and ready for 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% 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.