Patient Presentation
A former 35 week, appropriate for gestational age male, now 37.5 weeks was seen for well-care. He had regained his birth weight and was gaining weight appropriately while being fed 22 kcal/ounce premature infant formula, every 2-2.5 hours. His parents said that although he was still sleeping a lot they felt he was having more periods of wakefulness and the duration was also increasing. They had not noted any problems with apnea, dyspnea or color changes. His elimination was normal and they denied any jaundice concerns. The parents were planning on traveling 4.5 hours by car the following week for a family event, and wanted recommendations for traveling this far with their son.
The past medical history showed he was a premature infant born to first time parents who was kept an additional day after birth because of slow feeding and mild jaundice. He had received all of his routine care including passing his car seat tolerance test.
The pertinent physical exam showed the patient was now 3.34 kg (10-50% using premature infant growth chart), 47 cm length and 32 cm head circumference (10%) without any abnormal findings.
The diagnosis of a healthy preterm male who was gaining weight was made. No specific documentation regarding the duration of the car seat testing could be identified in the medical records. The parents said they thought it was about 2 hours of time. The pediatrician recommended that the family follow the recommendations of having one of the parents ride next to the infant during the trip and monitor him. She also recommended that they stop at least every 2 hours and get him out of the car seat. “Two hours or less is a good amount to travel. This is about how long he was tested. You both will also be tired and can switch the driving plus he will need to eat that often. You both could eat and drink something too,” she counseled.
Discussion
Safety is important for all infants and children. It is estimated that car restraints decrease injuries in those < 1 year by ~ 70%. About 10% of infants in the US are born prematurely and most are late preterm infants (34 week to 36 6/7 week gestational age). These infants do not have term infant physiology and are at risk for immature patterns in feeding, glycemic control, breathing, temperature, and overall development. They are at risk for cardiopulmonary events which commonly are apnea and/or bradycardia.
Babies who are at risk for cardiopulmonary events are recommended to have a car seat tolerance screening (CSTS) in their personal car seats or car beds (= devices). Babies tested should be tested for 90-120 minutes or the duration of travel whichever is longer. The testing should be performed in the infant’s personal device. It is recommended to be performed within 1-2 days of hospital discharge. Babies recommended to be tested are infants < 37 weeks gestation, with some hospital protocols including babies at risk for cardiorespiratory problems such as hypotonia (e.g. neuromuscular problems, Down syndrome), micrognathia (e.g. Pierre-Robin Sequence) and post-operative congenital heart disease. Babies who have low birth weight < 2500 grams are also often tested. Devices should only be used during travel and the amount of time in the device should be minimized. Babies should be properly positioned in an appropriate device and the device should be properly positioned in the car (e.g. most central position of the car possible such as the rear seat in the center, and not in the front seat). An adult to monitor the infant riding adjacent can be helpful but note that monitoring is probably easier with a car seat than car bed. An infant should never be unattended in a device in or out of the car.
The CSTS failure rate varies depending on the study. In one study low birth weight term infants had a 4.8% failure rate overall. Infants that failed were more likely to have a mother who tested positive for opiates. In another study late preterm infants had 4.6% failure rate overall. Infants with the highest failure rates were admitted both to the neonatal intensive care unit (NICU) and regular newborn nursery (8.5%). Many babies failed more than 1 testing (24%). “…[A] concerning number demonstrated unstable cardiorespiratory status in their semiupright car seat, even in those presumed to be the most mature with the fewest comorbidities.” A large number of these infants were only seen in the nursery while others needed additional intervention and transfer to the NICU. What these and other studies show is that late preterm infants though appearing healthy, are still at risk for adverse cardiopulmonary events during this critical time period of neurological development. Some studies have even shown increased rate of failure when compared to infants < 34 week gestation.
Infants who fail CSTS are often tried in a car bed. If the infant passes CSTS in a car bed they are usually discharged with one. Transitioning from car bed to car seat does not have specific guidelines. One literature review states, “Given the available literature, we recommend waiting 4 weeks or until a minimum [post-menstrual age] of 42-44 weeks, and repeating a CSTS prior to transitioning to a car seat for travel.”
Learning Point
“One conclusion that can definitely be drawn from the available research is that regardless of the type of travel device chosen, longer duration in each device leads to lower SpO2 and increased risk of desaturation and hypopnea. Direct observation by a caregiver during travel and limiting time in each device only to motor vehicle travel are of the upmost importance…Since the AAP recommended duration of CSTS is 90-120 min, we currently recommend that be the maximum time a neonate ride continuously in a car seat without a break…”
Questions for Further Discussion
1. What are the recommendations for how a term infant should use a car seat, and when can they transition to front-facing?
2. What are the differences between how infant car seats are designed and those for older children in booster seats?
3. What other screening should low for gestation age or preterm infants have before hospital discharge?
4. How should car seats be adjusted in the winter time? A review can be found here
Related Cases
- Disease: Car Seats | Child Safety | Motor Vehicle Safety
- Symptom/Presentation: Abnormal Laboratory Test | Apnea | Arrhythmia | Respiratory Distress
- Specialty: Neonatology | General Pediatrics
- Age: Premature Newborn | Newborn
To Learn More
To view pediatric review articles on this topic from the past year check PubMed.
Evidence-based medicine information on this topic can be found at SearchingPediatrics.com and the Cochrane Database of Systematic Reviews.
Information prescriptions for patients can be found at MedlinePlus for these topics: Motor Vehicle Safety and Child Safety.
To view current news articles on this topic check Google News.
To view images related to this topic check Google Images.
To view videos related to this topic check YouTube Videos.
Bull MJ, Engle WA, The Committee on Injury and Poison Prevention and the Committee on Fetus and Newborn. Safe Transportation of Preterm and Low Birth Weight Infants at Hospital Discharge. Pediatrics. 2009;123(5):1424-1429. doi:10.1542/peds.2009-0559
Davis NL. Car Seat Screening for Low Birth Weight Term Neonates. Pediatrics. 2015;136(1):89-96. doi:10.1542/peds.2014-3527
Davis NL, Shah N. Use of car beds for infant travel: a review of the literature. J Perinatol. 2018;38(10):1287-1294. doi:10.1038/s41372-018-0195-7
Magnarelli A, Shah Solanki N, Davis NL. Car Seat Tolerance Screening for Late-Preterm Infants. Pediatrics. 2020;145(1):e20191703. doi:10.1542/peds.2019-1703
Author
Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa
Pediatric Education 