Their findings, which contradict earlier studies on the subject, were published in this month's issue of Archives of Otolaryngology ? Head & Neck Surgery.
Obstructive sleep apnea syndrome (OSAS) is a serious medical problem affecting 500,000 children every year in the United States. Pediatric OSAS is commonly caused by enlarged tonsils and adenoids and is characterized by episodes of partial or complete upper airway obstruction that occur during sleep, including snoring, cyanosis (a bluish color of the skin and mucous membranes), and poor sleep quality. Daytime symptoms can include mouth breathing, behavior problems, hyperactivity and excessive daytime sleepiness.
Kevin D. Pereira, M.D., professor of otolaryngology at the UT Medical School and chief pediatric otolaryngologist at Memorial Hermann Children's Hospital, evaluated the association between body position and OSAS events during sleep in toddlers up to age three. Results came from sleep studies of 60 children at the hospital between Dec. 2001 and Dec. 2003.
The children underwent polysomnography (PSG, the continuous recording of physiologic variables during sleep) to evaluate OSAS, and later had their tonsils and adenoid tissue removed. The PSGs were analyzed for data on the respiratory disturbance index (RDI, an index measuring respiratory events that disturb sleep), time spent in each body position during sleep, the number of apnea events in each position, oxygen saturation, and time spent in each stage of sleep.
"The mean RDI rose when more than 50 percent of the time was spent in supine (face upwards) sleep," Pereira said. "There was even more of an increase when supine sleep comprised 75 percent of the total sleep time. In fact, the RDI in this position was greater than in all other positions combined.
"Our study indicates that supine sleep does correlate with an increase in RDI as well as with OSAS in patients younger than four," Pereira said. "This finding is in contrast to previous studies that have demonstrated no correlation between sleep position and obstructive sleep apnea in children."
Pereira, lead author of the study, urges physicians who use PSG in order to diagnose and manage sleep disorders in children to take into consideration the variables that may affect the validity of the results. "Lack of adequate supine sleep may be an important factor in symptomatic children with normal sleep study results," he said.
Pereira also notes that the study was not conducted on infants, so this study's findings shouldn't be confused with the practice of having infants sleep on their sides or back to help avoid Sudden Infant Death Syndrome.