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Electromyographic study of some accessory muscles of respiration in children with obstructive sleep apnea
Insights
Children with obstructive sleep apnea (OSA) show increased activity in inspiratory and expiratory muscles during sleep. This suggests complex airway obstruction mechanisms beyond simple muscle weakness in pediatric OSA.
Area of Science:
- Pediatric Pulmonology
- Sleep Medicine
- Respiratory Physiology
Background:
- Obstructive sleep apnea (OSA) is a common pediatric condition.
- The exact pathogenesis of pediatric OSA requires further elucidation.
- Understanding muscle activity patterns during sleep is crucial for diagnosing and managing OSA.
Purpose of the Study:
- To investigate the role of sternocleidomastoid (SCM), genioglossal (GG), and abdominal (ABD) muscle activity in the pathogenesis of pediatric OSA.
- To correlate muscle activity indices with blood gas levels (PACO2 and tcPO2) during sleep.
Main Methods:
- Surface electromyograms (EMGs) were used to record SCM, GG, and ABD muscle activity in 39 children undergoing polygraphic studies.
- An EMG activity index was developed for each muscle.
- Interpatient regression analysis correlated EMG amplitude with highest PACO2 and lowest tcPO2.
Main Results:
- Phasic inspiratory SCM activity was significantly more prevalent in children with OSA and correlated with increased PACO2 and decreased tcPO2.
- Phasic inspiratory GG activity was also more common in children with OSA and showed similar correlations with PACO2 and tcPO2.
- Phasic expiratory ABD activity was observed more frequently in children with OSA, indicating increased expiratory resistance.
Conclusions:
- Inspiratory (SCM), airway-maintaining (GG), and expiratory (ABD) muscles contract during partial airway obstruction in pediatric OSA.
- Augmented GG activity suggests pathogenic mechanisms in pediatric OSA beyond GG hypotonia.
- Expiratory ABD muscle activity indicates increased expiratory airway resistance in some children with OSA.
Abstract:
To further elucidate the pathogenesis of obstructive sleep apnea (OSA), we recorded sternocleidomastoid (SCM), genioglossal (GG), and abdominal (ABD) muscle activity, using surface electromyograms (EMGs), during 45 polygraphic studies in 39 children referred for possible OSA. For each muscle, an index of electromyographic (EMG) activity was developed, allowing an interpatient regression analysis of EMG amplitude versus highest PACO2 and lowest transcutaneous O2 tension (tcPO2) during sleep. Phasic inspiratory SCM activity was present during more than 50% of sleep time in 16 of 20 patients with OSA versus only 2 of 15 patients without OSA; SCM EMG activity increased with increasing PACO2 (r = 0.45, p less than 0.02) and decreasing tcPO2 (r = 0.51, p less than 0.01). Phasic inspiratory GG activity was present during more than 50% of sleep time in 15 of 18 patients with OSA versus none of 4 without OSA; GG EMG activity increased with increasing PACO2 (r = 0.51, p less than 0.05) and with decreasing tcPO2 (r = 0.60, p less than 0.02). Phasic expiratory ABD activity was present during more than 50% of sleep time in 10 to 20 patients with OSA versus 1 of 12 patients without OSA. These findings suggest the following conclusions: (1) inspiratory (SCM), airway-maintaining (GG), and expiratory (ABD) muscles contract during sleep-related partial airway obstruction in children; (2) augmented GG activity during periods of sleep-related partial airway obstruction suggests that pediatric OSA involves pathogenic mechanisms other than GG hypotonia; (3) expiratory ABD muscle activity suggests that some children with OSA have increased expiratory, as well as inspiratory, airway resistance during sleep.(ABSTRACT TRUNCATED AT 250 WORDS)