Changes in Upper Airway Size during Tidal Breathing in Children with Obstructive Sleep Apnea Syndrome

Abstract

We performed respiratory-gated magnetic resonance imaging to evaluate airway dynamics during tidal breathing in 10 children with obstructive sleep apnea syndrome (OSAS; age, 4.3 Ϯ 2.3 years) and 10 matched control subjects (age, 5.0 Ϯ 2.0 years). We hypothesized that respiratory cycle fluctuations in upper airway cross-sectional area would be larger in children with OSAS. Methods: Studies were performed under sedation. Respiratory gating was performed automatically at 10, 30, 50, 70, and 90% of inspiratory and expiratory volume. Airway cross-sectional area was measured at four ascending oropharyngeal levels at each increment of the respiratory cycle. Results: We noted the following in subjects with OSAS compared with control subjects: (1 ) a smaller upper airway cross-sectional area, particularly during inspiration; (2 ) airway narrowing occurred during inspiration without evidence of complete airway collapse; (3 ) airway dilatation occurred during expiration, particularly early in the phase; and (4 ) magnitude of cross-sectional areas fluctuations during tidal breathing noted in OSAS at levels 1 through 4 were 317, 422, 785, and 922%, compared with 19, 15 17, and 24% in control subjects (p Ͻ 0.001, p Ͻ 0.005, p Ͻ 0.001, and p Ͻ 0.001, respectively). Conclusions: Fluctuations in airway area during tidal breathing are significantly greater in subjects with OSAS compared with control subjects. Resistive pressure loading is a probable explanation, although increased airway compliance may be a contributing factor.

Effects of partial tonsillectomy on the immune functions of children with obstructive sleep apnea-hypopnea syndrome at early stage

“…Fregosi et al (2003) obtained similar results in slightly older, unsedated children, with a correlation between increasing tonsil cross-sectional area (CSA), soft palate CSA, and obstructive AHI. Arens et al (2005) found that even in asymptomatic children, an increased adenotonsillar size did correlate with increased nasopharyngeal airway narrowing, that is, increased tissue compliance, during inspiration.…”

Deposition of Inhaled Ultrafine Aerosols in Replicas of Nasal Airways of Infants

“…Experiments using nasal replicas are popular because they can be used for systematic studies in laboratories without the ethical limitations of human studies. Given that nasal airway cross sections do not change noticeably during the breathing cycle (Arens et al 2005), collecting images of infant extrathoracic airways is an alternative option to avoid the complexities of subject recruitment and in vivo studies. Moreover, although deposition of ultrafine aerosols in replicas with nasal hair is higher than without nasal hair for adults (Cheng et al 1993), this is not an issue for infants because they do not yet have any nasal hair.…”

Developmental Aspects of the Upper Airway: Report from an NHLBI Workshop, March 5-6, 2009

“…Other limitations of CT and MRI include motion artifact due to tidal breathing or active airway obstruction, the need for sedation in infants and young children to prevent motion artifact, and cost. Dynamic respiration-gated techniques with CT and MRI have been recently introduced by several groups to study airway dynamics, and may provide functional data based on measures of collapsibility (62,63). The utility of such imaging techniques, along with computation models of upper airway fluid and tissue mechanics are beginning to provide better understanding of the complex anatomical and functional interactions leading to OSAS and other respiratory disorders in both children and adults.…”