New Way to Detect Sleep-Disordered Breathing in Children

A new test for detecting sleep-disordered breathing in children could put an end to cumbersome and expensive overnight sleep studies, researchers report.

Sleep-disordered breathing is actually quite common in children, but is often undiagnosed. If left untreated, it can lead to a number of consequences, ranging from primary snoring to complete sleep apnea, which, in some cases, can impair a child's intellectual and physical development, explained Marcin Kawalski, from the sleep-disordered breathing laboratory at Mościcki Hospital in Chorzów, Poland.

Dr. Kawalski presented the findings at the European Respiratory Society 2013 Annual Congress.

His research team looked at "pulse transit time as a surrogate measure of night events in children. This method was compared with nocturnal oximetry, heart rate variability, and evaluation of the cortical arousals," Dr. Kawalski noted.

Pulse transit time is the time it takes the pulse pressure waveform to propagate through a length of the arterial tree. Aberrant times are proposed as a surrogate marker of breathing dysfunction.

Investigators conducted a retrospective review of children who had already been tested at the sleep laboratory and for whom pulse transit time measures were available.

They identified 153 children 3 to 14 years of age with recordings that were free of motion artifacts. "That is currently the greatest disadvantage of this method; motion artifacts can introduce errors in the reading," said Dr. Kawalski.

There was a strong correlation between pulse transit time and standard measures. A detection of at least 40 pulse transit time events corresponded to an obstructive apnea-hypopnea index score of greater than one, with a certainty level of 95.8%, which was significant in all age groups (confidence interval, 92.4% - 99.2%).

Going forward, Dr. Kawalski said he would like to optimize this method by incorporating smartphone technology. "I want to combine it with an accelerometer, which is how the phone senses the screen's orientation. I'm pretty sure this would solve most of the motion artifact problems, allowing for the filtering out of this aspect from the oxygen curve."

If this approach succeeds, pulse transit time would be a simple and inexpensive method of screening children for respiratory sleep disorders.

Other research on sleep-disordered breathing was presented by Sandra Chuang, MD, from Sydney Children's Hospital in Australia.

"In contrast to the pulse transit time approach, what I'm doing is looking at measures of the work of breathing," said Dr. Chuang. "By the time children stop breathing more than once per hour, you may have missed the opportunity to treat early enough to prevent the potential problems of neurocognitive side effects or blood pressure cardiovascular side effects."

"What we're trying to demonstrate is that some kids who don't stop breathing more than once per hour are, in fact, working really, really hard, and that perhaps we should treat these kids before they stop breathing," she added.

Dr. Chuang's team looked at surface electromyography readings of the diaphragm to identify labored breathing.

The mean age of the children enrolled in their study was 5.1 years. The 15 normal snorers had an obstructive apnea-hypopnea index score of no more than one per hour, the nine children with work-of-breathing issues had a score of no more than one per hour, and the nine with obstructive sleep apnea had a score of one or more per hour.

Although median electromyography values were lower in normal snorers (3.64 uV) than in those with work-of-breathing issues (7.21 uV) and those with obstructive sleep apnea (10.25 uV), the data suggest that even children not considered to have hazardous sleep-disordered breathing by obstructive apnea-hypopnea index criteria were, in fact, working much too hard to breath.

This is information that pulse transit time would not give you. These observations await verification in larger future studies, Dr. Chuang noted.

Dr. Chuang and Dr. Kawalski have disclosed no relevant financial relationships.

European Respiratory Society (ERS) 2013 Annual Congress: Abstracts P2593 and P2595. Presented September 10, 2013.

Neil Canavan • Medscape Medical News © 2013 WebMD, LLC

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