Effect of snoring and obstructive respiratory events on sleep architecture in adolescents.

OBJECTIVE: To evaluate the effect of snoring and obstructive respiratory events on the distribution of sleep stages and arousals in a nonselected group of adolescents from the general population. DESIGN: Cross-sectional study. SETTING: Randomly selected secondary schools in Seville, Spain. Patients A general population sample of 43 adolescents (mean [SD] age, 13.6 [1.77] years). INTERVENTIONS: A questionnaire for the investigation of sleep-related breathing disorders was administered. Symptoms were evaluated according to a 4-point frequency scale. Snorers answered "sometimes" or "often" to the question about snoring, and nonsnorers answered "never" or "rarely." All subjects underwent standard polysomnography at the sleep laboratory. RESULTS: Twenty-eight subjects were snorers; 15 were nonsnorers. No statistically significant differences were noted between both groups in the percentages of sleep stages, arousal index, awakenings, or wakefulness during sleep. Snorers showed a significantly higher number of respiratory arousals than nonsnorers (mean [SD], 1.14 [1.5] vs 0.33 [0.6], P<.05). However, neither the apnea-hypopnea index (AHI) nor the oxygen desaturation index correlated with the arousal index. Twelve snorers (27.5%) had an AHI of 2 or more; 13 nonsnorers (30.2%) had an AHI of less than 2. Snorers with some obstructive respiratory events had a significantly higher number of awakenings, a lower percentage of stage 4 sleep, and a higher number of respiratory events compared with nonsnorers. However, the total number of arousals and the arousal index were similar for both groups. Wakefulness during sleep tended to be longer in snorers than in nonsnorers although differences were not significant. The percentage of respiratory events that terminated with an arousal was greater in snorers who had an AHI of 2 or more than in nonsnorers who had an AHI of less than 2 (mean [SD], 8.4% [9.5%] vs 4.9% [11.53%], P<.05). CONCLUSIONS: These data indicate normal sleep architecture in the adolescents. Although snorers as well as adolescents with some polysomnographic abnormality showed a higher number of respiratory arousals than control subjects, most obstructive events did not terminate with a cortical arousal, which may suggest that adolescents share with younger children this mechanism for preserving sleep architecture.

Echocardiographic parameters in adolescents with sleep-related breathing disorders.

Few data are known about the effects of sleep-related breathing disorders (SRBD) on the cardiovascular system in adolescents. Forty healthy adolescents (mean age, 13.7 +/- 1.6 years) answered a questionnaire regarding symptoms of sleep-related breathing disorders (SRBD) and underwent a cardiorespiratory polygraphy and echocardiography. Echocardiographic data in snorers with polygraphic abnormalities suggestive of SRBD (positive group, n = 29) were compared with the results in nonsnorers without polygraphic abnormalities (n = 11) who were included in the control group. Ventricular dimensions and indices of left ventricular systolic function were within normal limits and were not significantly different between the two groups. Indices of left ventricular diastolic function were also within normal limits, but isovolumetric relaxation time (IVRT) was significantly longer among the positive group (72.5 +/- 8.4 msec) than among the controls (65.1 +/- 7.9 msec) (P = 0.018). Multiple regression analysis showed that posterior wall thickness was predicted by a model that included cardiac events related with respiratory events and/or desaturations, and respiratory disturbance index (RDI) in supine position. Deceleration of early diastolic flow was predicted by RDI, percentage of total recording time with SaO(2) < 90% (CT(90)), and age; the variability of isovolumetric relaxation time was predicted by a model that included RDI in supine position. We found a significant relationship between polygraphic parameters suggestive of SRBD and echocardiographic measurements of ventricular dimensions and diastolic function. Also, echocardiographic parameters suggestive of some degree of left ventricular diastolic dysfunction were found in snoring adolescents with polygraphic abnormalities.