Does Tongue Size Contribute to Risk of Airway Narrowing in Preterm Infants Sitting in a Car Safety Seat?

Abstract

Background Preterm infants are at risk of narrowing of the upper airway while restrained in infant car seats, leading to secondary apnea. However, some infants are able to maintain a normal airway. We hypothesized that this might reflect relatively smaller tongue size.

Methods We retrospectively analyzed previously reported respiration-timed lateral radiographs of the upper airways of 17 preterm infants ready for discharge (32.6 ± 1.0 weeks gestation at birth, and 37.8 ± 9.7 days old at study) taken during sleep, first in a car safety seat with an insert that allowed the head to remain upright, and then without the insert, when the head slumped forward. The presence of air above the tongue was used as an index of relative tongue size.

Results A smaller airspace around the tongue (relatively larger tongue) was associated with greater narrowing of the upper airway when the head was flexed forward in sleep (p < 0.002). In contrast, there was no significant correlation between baseline airway size and change in airway size (r ² = 0.16, p = 0.11).

Conclusion The present study supports the hypothesis that the vulnerability of preterm infants to airways compromise while restrained in a car safety seat may be in part related to relative tongue size.

Keywords

car safety seat - preterm infant - upper airway size - tongue size

• References

• 1 American Academy of Pediatrics Committee on Injury and Poison Prevention and Committee on Fetus and Newborn. Safe transportation of premature infants. Pediatrics 1991; 87 (1) 120-122
• 2 Willett LD, Leuschen MP, Nelson LS, Nelson Jr RM. Risk of hypoventilation in premature infants in car seats. J Pediatr 1986; 109 (2) 245-248
• 3 Tonkin SL, Gunn TR, Bennet L, Vogel SA, Gunn AJ. A review of the anatomy of the upper airway in early infancy and its possible relevance to SIDS. Early Hum Dev 2002; 66 (2) 107-121
• 4 Bosma J. Respiratory functions. In: Bosma JF, Showacre J, , eds. Development of Upper Respiratory Anatomy and Function: Implications for Sudden Infant Death Syndrome. Washington DC: DHEW Publication No (NIH) 85 941.V; 1975: 15-49
• 5 Stark AR, Thach BT. Mechanisms of airway obstruction leading to apnea in newborn infants. J Pediatr 1976; 89 (6) 982-985
• 6 Thach BT, Stark AR. Spontaneous neck flexion and airway obstruction during apneic spells in preterm infants. J Pediatr 1979; 94 (2) 275-281
• 7 Tonkin SL, McIntosh CG, Hadden W, Dakin C, Rowley S, Gunn AJ. Simple car seat insert to prevent upper airway narrowing in preterm infants: a pilot study. Pediatrics 2003; 112 (4) 907-913
• 8 McIntosh CG, Tonkin SL, Gunn AJ. Randomized controlled trial of a car safety seat insert to reduce hypoxia in term infants. Pediatrics 2013; 132 (2) 326-331
• 9 Tonkin SL, McIntosh CG, Nixon GM, Rowley S, Gunn AJ. Can we reduce episodes of haemoglobin desaturation in full-term babies restrained in car seats?. Acta Paediatr 2008; 97 (1) 105-111
• 10 Siebert JR, Haas JE. Enlargement of the tongue in sudden infant death syndrome. Pediatr Pathol 1991; 11 (6) 813-826
• 11 Lundström A, Lundström F. The Frankfort horizontal as a basis for cephalometric analysis. Am J Orthod Dentofacial Orthop 1995; 107 (5) 537-540
• 12 Gunn TR, Tonkin SL. Upper airway measurements during inspiration and expiration in infants. Pediatrics 1989; 84 (1) 73-77
• 13 Hadar T, Yaniv E, Shvili Y, Koren R, Shvero J. Histopathological changes of the nasal mucosa induced by smoking. Inhal Toxicol 2009; 21 (13) 1119-1122
• 14 Katz ES, Mitchell RB, D'Ambrosio CM. Obstructive sleep apnea in infants. Am J Respir Crit Care Med 2012; 185 (8) 805-816