Cross‐sectional case‐control study of the relationships between pharyngeal compliance and heart rate variability indices in childhood obstructive sleep apnoea. (20th April 2021) - Bokov, Plamen
Summary: A combination of noradrenergic and antimuscarinic agents reduces the apnea–hypopnea index (AHI) in adult patients with obstructive sleep apnoea (OSA) via reduced upper airway collapsibility, suggesting that a shift in the sympathovagal balance improves OSA. The objectives of our present case‐control study were to assess heart rate variability (HRV) indices in the stages of sleep in children with and without OSA to evaluate OSA‐induced sleep HRV modifications and to assess whether increased collapsibility measured during wakefulness is associated with reduced sympathetic activity during non‐rapid eye movement (NREM) sleep. Three groups of 15 children were matched by sex, age, z ‐score of body mass index and ethnicity: non‐OSA (obstructive AHI [OAHI] <2 events/hr), mild (OAHI ≥2 to <5 events/hr) or moderate–severe (OAHI ≥5 events/hr) OSA. Pharyngeal compliance was measured during wakefulness using acoustic pharyngometry. HRV indices (time and frequency domain variables) were calculated on 5‐min electrocardiography recordings from polysomnography during wakefulness, NREM and REM sleep in periods free of any event. As compared to children without OSA, those with OSA ( n = 30) were characterised by increased compliance and no physiological parasympathetic tone increase in REM sleep. Children with increased pharyngeal compliance ( n = 21) had a higher OAHI due to higher AHI in NREM sleep, whereas their sympathetic tone was lower than that of those with normal compliance ( n = 24). In conclusion, children with increased pharyngeal compliance exhibit decreased sympathetic tone associated with increased AHI in NREM sleep. Therapeutics directed at sympathovagal balance modifications should be tested in childhood OSA.