Published online June 1, 2005
PEDIATRICS
Vol. 115
No. 6
June 2005, pp.
1789
(doi:10.1542/peds.2005-0495)
Airway Obstruction in Premature Newborns: A Missing Link
Daniel K. Ng, FRCP
Lettie C. Leung, FHKAM(Paed)
Tsz-fun Tong, FHKAM(Paed)
Chung-hong Chan, BSc
Siu-fong Wong, BSc
Department of Paediatrics
Kwong Wah Hospital
Kowloon, Hong Kong
To the Editor.—
We read with interest the January 2005 Pediatrics article by Marlier et al,1 who evaluated the therapeutic value of pleasant odor in the treatment of neonatal apneas unresponsive to caffeine and doxapram. In the Marlier et al study, "cessation in breathing movements >20 seconds" was used to define central apnea. Recent evidence suggests that obstruction of the airway is frequently present in these so-called central apneas.2 Idiong et al3 analyzed >4000 apneas in preterm neonates and found that central apneas occurred predominately with durations of <10 seconds, whereas those apneas >10 seconds were usually mixed apneas (ie, central followed by an obstructive component in the same episode). Hence, the so-called central apneas in the Marlier et al study might be mostly mixed apneas. It would be interesting to compare the effect of continuous positive airway pressure with that of vanillin in the treatment of this group of apneas.
Another major drawback of the study is the absence of airflow detection, which renders the differentiation of apnea into obstructive, mixed, and central apneas rather difficult. The airflow detection in neonates was reported by Lemke et al,4 who also suggested the use of cardiac waveform oscillation coupled with airflow tracing to classify central, obstructive, and mixed apnea in neonates. Distribution of different kinds of apneas during sleep in neonates was reported. During quiet sleep, 81% of apnea events were central, 18% were mixed, and 1% were obstructive. During indeterminate sleep, the prevalence of mixed and obstructive apnea increased to 
25% and 5%, and central apnea dropped to 70%.3 This differentiation is important for advancing the understanding of apnea in neonates; it also carries a prognosis implication, because obstructive sleep apnea was associated with apparent life-threatening events.5
Marlier et al conducted a series of tests (radiography, echocardiography, and cranial ultrasound) in all included neonates to detect major birth deformities. However, an important area (ie, the upper airway) was not assessed in the Marlier et al study. Upper airway obstruction (eg, laryngomalacia) would predispose to occurrence of apnea, obstructive or otherwise. We recently reported a case of neonatal obstructive sleep apnea secondary to pharyngomalacia and laryngomalacia in a day-3 neonate.6 In our opinion, endoscopy should be incorporated as routine in the work-up for neonates with unexplained apnea or desaturation even in the absence of stridor; we recently identified 2 premature neonates with recurrent desaturation due to obstructive apnea caused by laryngomalacia without stridor.
REFERENCES
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Pediatrics. 2005;115
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- Lemke RP, Al-Saedi SA, Alvaro RE, et al. Use of a magnified cardiac airflow oscillation to classify neonatal apnea.
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- Guilleminault C, Pelayo R, Leger D, Philip P, Ohayon M. Sleep-disordered breathing and upper-airway anomalies in first-degree relatives of ALTE children.
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- Ng DK, Lee RSY. Obstructive sleep apnea secondary to pharyngolaryngomalacia of a baby with Down syndrome.
Int J Pediatr Otorhinolaryngol. 2005; In press
PEDIATRICS (ISSN 1098-4275). ©2005 by the American Academy of Pediatrics
Related articles in Pediatrics:
- Airway Obstruction in Premature Newborns: A Missing Link: In Reply
- Luc Marlier, Christophe Gaugler, and Jean Messer
Pediatrics 2005 115: 1789-1790.
[Extract]
[Full Text]
