NEW YORK (Reuters Health) – Very young children with obstructive sleep apnea who sleep on their backs (the “supine” position) appear to have more respiratory problems, as measured by increases in the respiratory disturbance index (RDI), new research shows. As such, the severity of the apnea could be underestimated in children who do not spend much time in this position, according to the authors.

Obstructive sleep apnea syndrome is a condition in which airways become blocked periodically during sleep and breathing stops for brief periods. Symptoms improve in adults with this condition when they avoid the supine position, note Dr. Kevin D. Pereira and colleagues, from the University of Texas Health Science Center at Houston, in the Archives of Otolaryngology–Head & Neck Surgery.

To assess the effect of body position on sleep apnea in children 3 years of age or younger, the team analyzed data from 60 children with the condition who underwent polysomnography, a test used to diagnose obstructive sleep apnea, as part of their work-up.

The RDI increased as the amount of time in the supine position rose. When more than half the sleeping time was spent in the supine position, the average RDI rose from 5.6 to 8.5. When this position accounted for 75 percent of sleep time, the RDI increased further to 10.5.

The average RDI was also much higher during rapid eye movement, or “REM,” sleep than in other sleep stages: 20.5 vs. 5.6, the report indicates.

“The most significant finding in the study was that the RDI in the supine position was greater than in all other positions combined,” the authors write.

“A combination of reduced rapid eye movement sleep and increased nonsupine sleep may invalidate the findings of polysomnography” in very young children with obstructive sleep apnea,” they conclude.

SOURCE: Archives of Otolaryngology–Head and Neck Surgery, November 2005.