Clinical and PSG Characteristics of Children with Mild OSA and Respiratory Events Terminated Predominantly with Arousal

Polysomnographic Characteristics of Sleep Architecture in Children With Obstructive Sleep Apnea

BACKGROUND

The conventional measure of sleep fragmentation is via polysomnographic evaluation of sleep architecture. Adults with OSA have disruption in their sleep cycles and spend less time in deep sleep stages. However, there is no available evidence to suggest that this is also true for children and published results have been inconclusive.

OBJECTIVE

To determine polysomnographic characteristics of sleep architecture in children with OSA and investigate effects relative to OSA severity.

METHODS

Overnight polysomnograms (PSG) of children referred for suspected OSA were reviewed. Subjects were classified by apnea hypopnea index (AHI). PSG parameters of sleep architecture were recorded and analyzed according to OSA severity.

RESULTS

Two hundred and eleven children were studied (median age of 7.0 years, range 4-10 years) Stage N1 sleep was longer while stage N2 sleep and REM sleep was reduced in the OSA group when compared to those without OSA (6.10 vs 2.9, P < .001; 42.0 vs 49.7, P < .001; 14.0 vs 15.9, P = .05). The arousal index was also higher in the OSA group (12.9 vs 8.2, P < .001). There was a reduction in sleep efficiency and total sleep time and an increase in wake after sleep onset noted in the OSA group (83.90 vs 89.40, P = .003; 368.50 vs 387.25, P = .001; 40.1 ± 35.59 vs 28.66 ± 24.14, P = .007; 29.00 vs 20.50; P = .011). No significant difference was found in N3 sleep stage (33.60 vs 30.60, P = .14).

CONCLUSION

We found evidence that children with OSA have a disturbance in their sleep architecture. The changes indicate greater sleep fragmentation and more time spent in lighter stages of sleep. Future research is needed and should focus on more effective methods to measure alterations in sleep architecture.

[Prevalence of childhood obstructive sleep apnoea syndrome in a referral sleep unit]

INTRODUCTION

Obstructive sleep apnoea syndrome (OSAS) affects between 1% and 6% of children. Its diagnosis includes: a) snoring and/or apnoea; and b) an apnoea and hypopnoea index >3/hour obtained by polysomnography (PSG). The main aim of this work is to determine the prevalence of OSAS in our study population.

PATIENTS AND METHODS

We conducted a descriptive study with a sample of 151 children aged between 1 and 12 years, who had been referred to the sleep unit of the Hospital General Universitario Gregorio Maranon for a PSG. We analysed the demographic variables sex and age; the clinical variables snoring, apnoeas and tonsillar hypertrophy; and the presence of OSAS based on the polysomnographic diagnostic criterion of an apnoea and hypopnoea index >3/hour.

RESULTS

The mean age of the sample was 5.37 years (standard deviation: 3.05) and 64.9% were males. In 90.1% of cases, the reason for the visit was suspected OSAS. Snoring, apnoeas and tonsillar hypertrophy were observed in 73.5, 48.7 and 60% of cases, respectively. OSAS was diagnosed en 19 children (12.6%); in 13.5% of snorers; in 15.1% of those with apnoeas; and in 15.6% of the children with tonsillar hypertrophy.

CONCLUSIONS

In our study, the prevalence of OSAS in children was 12.6%, which is higher than that reported in most epidemiological studies that include PSG for the diagnosis of OSAS.