Improved long-term autonomic function following resolution of sleep-disordered breathing in preschool-aged children

• Published in: Sleep & breathing Vol. 20; no. 1; pp. 309 - 319
• Main Authors: Walter, Lisa M., Biggs, Sarah N., Nisbet, Lauren C., Weichard, Aidan J., Hollis, Samantha L., Davey, Margot J., Anderson, Vicki, Nixon, Gillian M., Horne, Rosemary S. C.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-03-2016; Springer Nature B.V
• Subjects: Autonomic Nervous System - physiopathology; Blood Pressure - physiology; Child, Preschool; Dentistry; Dopamine - urine; Electrocardiography; Epinephrine - urine; Female; Follow-Up Studies; Heart Rate - physiology; Humans; Internal Medicine; Male; Medicine; Medicine & Public Health; Neurology; Otorhinolaryngology; Pediatrics; Pediatrics • Original Article; Pneumology/Respiratory System; Preschool children; Pulse Wave Analysis; Respiratory diseases; Signal Processing, Computer-Assisted; Sleep Apnea, Obstructive - physiopathology; Sleep Apnea, Obstructive - therapy; Sleep disorders; Treatment Outcome; Power spectral analysis; Pediatrics; Autonomic nervous system; Obstructive sleep apnea
• ISSN: 1520-9512; 1522-1709
• DOI: 10.1007/s11325-015-1268-x

Purpose
Sleep-disordered breathing (SDB) prevalence peaks in preschool children and is associated with deficits in cardiovascular functioning during sleep. No long-term studies have investigated the effects of SDB resolution in mitigating these outcomes. We hypothesized that following 3 years, normalization of alterations to heart rate (HR), pulse transit time (PTT), heart rate variability (HRV), and urinary catecholamines identified at the initial diagnosis would be associated with resolution of SDB.
Methods
Forty-five children with SDB and 28 non-snoring controls underwent polysomnography at baseline (3–5 years) and follow-up (6–9 years). Children were classified into control, resolved, and unresolved SDB. Resolution was defined as an obstructive apnea–hypopnea index (OAHI) ≤1 event/h, no snoring on polysomnography (PSG), or indicated by parents. PTT is an inverse surrogate measure of blood pressure change. HRV was assessed using power spectral analysis.
Results
There was no change in PTT or HR between studies for any group. Our HRV data suggest reduced parasympathetic activity in children whose SDB resolved and increased parasympathetic activity in children whose SDB remained the same or worsened at follow-up. We identified a significant correlation between low frequency power and urinary dopamine and adrenaline levels at follow-up in the unresolved group, suggesting increased sympathetic activity in children with unresolved SDB.
Conclusion
Our findings suggest an association between resolution of SDB and normalization of HRV in the long term in these preschool children and an augmented sympathetic activity in the children with residual SDB. This highlights the autonomic impact of SDB in young children and the importance of detection and treatment.