Car Seat Insert for Preemies

 Simple Car Seat Insert to Prevent Upper Airway Narrowing in Preterm Infants: A Pilot Study. Tonkin SL, McIntosh CG, Hadden W et al. PEDIATRICS (Oct 2003); 112 :907-913.

 Objectives. To test prospectively the hypothesis that an infant car seat modification to allow the infant’s head to rest in a neutral position on the trunk would prevent narrowing of the upper airway and thus reduce oxygen desaturation in preterm infants who are restrained in car seats.

Methods. Seventeen preterm infants who were approved for discharge were evaluated in a car seat for newborns, with and without a foam insert that provided a slot for the back of the infants’ head. Respiration timed inspiratory radiographs for assessment of upper airway dimensions were taken during quiet sleep in each position. Infants were monitored in each position for 30 minutes with continuous polygraphic recording of respiratory, cardiac, and nasal airflow activity and pulse oximetry.

Results. Placement of the insert in the car seat was associated with a larger upper airway space (mean ± standard deviation, 5.2 ± 1.3 vs 3.6 ± 1.4 mm). This radiologic improvement was associated with a significant reduction in the frequency of episodes of oxygen desaturation to <85% (1.5 ± 2.1 vs 3.5 ± 3.5 episodes/infant), of bradycardia <90 bpm (0.1 ± 0.3 vs 1 ± 1.7), and of arousal (median [25th, 75th], 2.5 [1.3, 4.0] vs 5.0 [4.0, 7.0]).

Conclusions. The cause of oxygen desaturation in preterm infants who are restrained in car seats is multifactorial. The present data strongly support the hypothesis that flexion of the head on the body is a significant contributor to these episodes and that the mechanism is posterocephalic displacement of the mandible, leading to narrowing of the upper airway. Critically, this pilot study demonstrates that the frequency of episodes of desaturation in a standard newborn car seat can be substantially reduced by placement of a simple foam insert that allows the infant to maintain the head in a neutral position on the trunk during sleep. 

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Comments.  The traditional car seat inserts that we currently use for preterm infants stabilize the baby’s head in the midline, but do not prevent flexion of the head.  The authors demonstrate that flexion of the head causes narrowing of the baby’s upper airway and leads to desaturation episodes.  The new insert is a foam cushion with a recess cut out for the baby’s occiput.  This maintains the head with mild extension, the “sniffing” position that we use to open the airway.  Great Idea!  I hope that these inserts will be commercially available soon.  ABK.