SAN DIEGO—Sleep studies in infants are often a reasonable option when there is nasal obstruction, but they are not always necessary, experts said during a panel held here at the Triological Society Combined Sections Meeting.
Romaine Johnson, MD, MPH, associate professor of otolaryngology-head and neck surgery at the University of Texas Southwestern in Dallas, said the infant airway is more compliant and more prone to collapse. Making matters more challenging, an infant’s mechanisms for protecting itself against obstructions are not well developed.
“Things are going to be worse if they do have obstructions,” he said. “They have to breathe faster, they have low lung volumes, and everything gets worse when they get into REM sleep. So all of those things need to be considered in terms of respiratory physiology.”
Infants don’t get aroused in states of hypoxemia as adults do. Instead, there is a “vicious cycle,” and activation of dilators actually drops, just worsening the situation, he said.
Clinical signs and symptoms are poor predictors of obstructive sleep apnea (OSA) in infant patients, so Dr. Johnson is “very comfortable” using sleep studies and endoscopy liberally when OSA is suspected, he said.
Stacey Ishman, MD, MPH, surgical director of the Upper Airway Center at Cincinnati Children’s, said clinicians need to distinguish between children who need further testing and those who don’t. That is because about 25% of normal infants have some features that suggest OSA, such as noisy breathing and paradoxical breathing, in which the chest wall moves in rather than out when a breath is taken. Snoring is often not a prominent symptom in these very young children and infants, she said.
Unless I’m looking for laryngomalacia or vocal fold motion, I tend to go straight to the DISE. —Stacey Ishman, MD, MPH
Sleep study parameters that call for treatment are an obstructive apnea-hypopnea index (oAHI) above five events per hour, oxygen saturations below 90% for 2% or more of total sleep time, carbon dioxide levels of 50 mmHG for at least 10% of total sleep time or a peak partial pressure of CO2 (pCO2) of 60 mmHG, or more than five central events per hour, she said.
In a study of 1,258 children, including infants, who underwent sleep studies for suspected OSA, Dr. Ishman and colleagues found that 53.2% did have OSA. But they also found a variety of other conditions, including central sleep apnea in about 1%, periodic limb movements of sleep in 7%, hypoventilation in 7%, and non-OSA snoring in 15%. About 3% had alveolar hypoventilation syndrome, and another 2% had non-apneic hypoxemia (Otolaryngol Head Neck Surg. 2017;157:1053-1059).
This, Dr. Ishman said, suggests that, beyond OSA, “the sleep study itself may have some value in [identifying] conditions that would be treated differently.”
Drug-Induced Sleep Endoscopy
Dana Thompson, MD, division head of otolaryngology at Ann and Robert H. Lurie Children’s Hospital of Chicago and professor of otolaryngology at Northwestern University’s Feinberg School of Medicine, said drug-induced sleep endoscopy (DISE) can complement or replace sleep studies in infants, which can be a particular help when infant sleep-study access is limited.
“Of all the board-certified sleep medicine physicians, only 5% really have any experience in children,” she said. Of all the accredited sleep centers in the U.S., she said, only a third of them study children under age 13.
In DISE, the goal is to create a level of anesthesia that mimics sleep.
“The advantage is it allows a dynamic examination in identifying exact sites so that you can do a targeted and tailored surgery,” she said.
A 2017 review found that most clinicians agree that DISE is appropriate for children with persistent OSA after tonsillectomy and adenoidectomy for helping to guide surgical intervention (Laryngoscope Investig Otolaryngol. 2017;2:423-431). The literature shows that DISE is particularly good at identifying obstruction that happens at multiple levels of the airway (Eur Arch Otorhinolaryngol. 2017;274:2319-2325). Studies of pediatric scoring systems have found that DISE scores correlate well with apnea-hypopnea index scores.
A Four-Month-Old with Troubling Sleep
The panelists discussed the case of a four-month-old with nightly pauses in breathing, an oxygen desaturation index of 3.5 events an hour, and oxygen saturations of less than 90% for 2.1% of the child’s total sleeping time.
Dr. Johnson said that, based on pictures of the child, he wouldn’t worry about a failure to thrive.
“That would be a big determinant for me on how aggressive I’m going to be: Is there good weight gain or is there poor weight gain? Also, what does the physical exam show?” he said.
Dr. Johnson said he would almost always do a flexible endoscopy to see how congested the nose is, whether there is adenoid hypertrophy or nasal obstruction, and how the upper airway looks. If the exam was normal, he would likely order a sleep study. If it was, say, obvious laryngomalacia, he would talk to the family and consider observing for a short time or moving right to surgery.
Dr. Thompson said that in these cases she often asks the family to bring in smartphone video of their children sleeping so they can describe what concerns them. In this case, she said, “I’m not sure I would get a sleep study” unless there were comorbidities such as prematurity, genetic and syndromic conditions, or concerns for neurologic disease. Depending on those other considerations, she would probably do an awake nasopharyngoscopy and laryngoscopy and then DISE.
Dr. Ishman said she likely would have enough data to avoid a sleep study.
“This is an abnormal oximetry study,” she said. “So I actually don’t think you need a sleep study; however, you might want one after whatever intervention (you choose), if you do one.”
Dr. Ishman said she has stopped using the flexible scope in the office very much because she knows she’ll do a DISE anyway.
“Unless I’m looking for laryngomalacia or vocal fold motion, I tend to go straight to the DISE,” she said.
Dr. Thompson said the flexible endoscope exam can buttress the findings in a meaningful way. She said sometimes she sees that the vocal cords are not opening correctly while a patient is awake—and if she also sees this when the patient is asleep, it reinforces for her that it is a real issue.
Getting Help for Patients
Mary Dorr, FNP, who works in a rural family practice in northern Louisiana, said parents will sometimes bring a child to the office and say, “I know they look fine now, but sometimes there are just pauses when they sleep, and it gets me really concerned.” A referral to a pediatric otolaryngologist will often mean a two-hour drive and a six- to eight-week wait, she said, so she wondered whether a sleep study should be ordered right away.
Dr. Thompson said sleep-study access might be difficult there and that otolaryngology referral “is probably going to expedite the care that the child needs.”
Dr. Ishman said ordering oximetry could be a fast, inexpensive, and good first option, since many centers don’t perform sleep studies on infants, even those that study older children.
“That might be an option for you if you want to do something that will expedite their care,” she said. “And then you’ll be able to figure out, ‘Hey, this is something that I’m going to send to the ER (at a larger center)’ or ‘This is something I can wait six to eight weeks for a pediatric otolaryngologist.”
Thomas Collins is a freelance medical writer based in Florida.