WASHINGTON, DC-Sleep-disordered breathing (SDB) is a major problem in children because it is associated with behavioral, cognitive, and emotional morbidity. The silver lining to this cloud is that removal of the tonsils and adenoid tissue (T&A) normalizes children’s sleep and improves their behavior problems, while achieving dramatic reduction in health care resource utilization and cost savings.
Children with SDB exhibit sleepiness, cardiovascular problems, poor growth, depressed mood, and a spectrum of behavioral problems that can include aggression, poor academic performance, irritability and hyperactivity, and inattention, explained Norman R. Friedman, MD, Associate Professor at the University of Colorado Health Sciences Center and Director of the Pediatric Pulmonary Sleep Lab in Denver.
A large survey of 1600 cases showed that children who snored between the ages of two and six were more likely to be at the bottom of their class, Dr. Friedman said. Another review of 12 studies showed that children with SDB had lower intelligence quotients (IQ) compared with controls. Dr. Friedman explained that even mild SDB is associated with lapses in attention and lower IQ, and that his threshold for intervention has dropped.
If a child exhibits night-time symptoms (snoring, gasping for breath, noisy breathing, frequent awakening, and parasomnias), daytime symptoms (described above), and enlarged tonsils, he advises removing the tonsils.
If snoring is present, I am less likely to get a sleep study before intervening, he said.
Dr. Friedman said that children at high risk for SDB should undergo sleep testing. Factors that place children at high risk include prematurity, age under two, and obesity, Down syndrome, genetic or neuromuscular disorders, and sickle cell disease.
Sleep studies can be complicated to interpret. Also, different labs use different indices and cutoff points. The main indices used include the Apnea/Hypopnea Index (AHI), the Central Apnea Index (CAI), the Respiratory Disturbance Index (RDI), the Arousal Index (AI), and the Respiratory Event-Related Arousal Index (RERA). These indices measure different things, he said.
Sleep labs use different cutoff points for these indices to define clinical significance.
New studies suggest that more than five events per hour represents a clinically significant AHI, he said. However, if oxygen desaturations are associated with the respiratory events, the clinical relevance threshold drops below five events per hour. Dr. Friedman also emphasized the importance of measuring end-tidal CO2. The number can be normal but the wave form can be abnormal, signaling decreased ventilation, he commented.
The single most important piece of paper obtained from a sleep study is a hypnogram, which provides an all night view of the patient’s sleep parameters.
You need to understand the terms used in the sleep report and what the tests represent. It is important to have a good relationship with your sleep expert colleague so that he or she can help you interpret the study results. Also, the same lab should be used for all studies, Dr. Friedman emphasized.
In the current era of evidence-based medicine, outcomes research is needed to validate treatment modalities, explained Ron B. Mitchell, MD, Professor of Otolaryngology at St. Louis University School of Medicine and the Cardinal Glennon Children’s Medical Center in St. Louis. Dr. Mitchell reviewed data from the past five years related to treatment of SDB and outcomes.
A review of 14 studies using polysomnography (PSG) to evaluate outcomes in children with SDB and obstructive sleep apnea (OSA) found that T&A had success rates ranging from 79% to 92% (Brietzke et al. Head Neck Surg 2006). Limitations of this review were that the studies had small sample sizes, studied different disorders, used different sleep labs, and had different definitions of success, he said.
-Norman R. Friedman, MD
Another review by Dr. Mitchell and colleagues found that sleep parameters improved significantly post-surgery in 80 healthy nonobese children with SDB. After T&A, 71% to 94% were normalized, depending on the sleep parameter. In general, around 80% to 85% of children get better, he said.
The most dramatic improvements were observed in children who had more severe SDB, but every child who had surgery showed some improvement. Every child with AHI < 10 normalized; 73% with AHI > 10 normalized. Tonsil size was not a predictor of improvement, he said.
Conversely, 15% to 20% of healthy normal-weight children do not normalize following surgery. This means that of the 250,000 T&A procedures performed annually in the United States, about 50,000 children do not have normalized sleep parameters following surgery.
Quality of Life After T&A
Dr. Mitchell said that the impact of SDB on children’s quality of life is considerable, and he believes it may be underestimated. Children with SDB have significantly worse quality of life compared with healthy controls, similar to the quality of life of children with juvenile rheumatoid arthritis and asthma. This is particularly true for the emotional, behavioral, and parental impact, Dr. Mitchell commented.
Surgery was found to improve quality of life in a study by Dr. Mitchell and colleagues (Arch Otolaryngol Head Neck Surg 2004). Using the OSA-18 (a validated quality of life instrument), mean total score improved for sleep disturbance, physical suffering, emotional distress, daytime problems, and caregiver concerns.
Surgery has placebo effects, he acknowledged, but if the effects were merely placebo, then the improvements in quality of life should deteriorate over time. However, follow-up of the same set of patients showed that the improvement in quality of life after surgery was maintained at two years (Mitchell R. Arch Otolaryngol Head Neck Surg 2006). In fact, the improvements in quality of life were more robust than improvements on polysomnography measures. To illustrate this point, he cited another study showing that 97% of patients had improved symptoms post-surgery, whereas only 80% of this group were improved on polysomnography.
Turning to behavioral measures of improvement following T&A, Dr. Mitchell noted, This area is much more murky than polysomnography or quality of life. These measures rely on parents’ perceptions. Not every child with sleep problems has behavioral problems.
Studies do show that behavior improves following surgery, but the extent of improvement depends on the baseline scores, he said. One study looked at a measure of hyperactivity and showed that preoperatively 10 children were severely impaired, 7 had mild impairment, and 35 were normal; following surgery, 47 were normal, 5 had mild hyperactiviity, and none were severely hyperactive. Behavioral measures require further study, he said.
Not all children with SDB have problems before surgery, and not all behavioral problems resolve post-surgery, Dr. Mitchell emphasized. Children who score way outside normal parameters on behavioral measures benefit the most from surgery.
He said that 30% to 40% of children have behavioral abnormalities preoperatively and 50% to 60% of these children normalize after surgery. As the most severely behaviorally disturbed children are most likely to benefit from T&A, documenting behavior may affect the decision to undertake surgery.
Health Care Utilization
In addition to improved sleep, improved quality of life, and improved behavior, another reason to consider surgery for children with SDB is related to economics. A recent study found a 215% elevated health care resource utilization in children with SDB compared with controls, which was mainly reflected in outpatient visits and hospital visits (Tarasiuk A. Am J Respir Crit Care Med 2007). In fact, all studies of health care utilization to date demonstrate reduced utilization, Dr. Mitchell said. One study showed that health care utilization costs were reduced by one-third after T&A, he said, and upper respiratory infections were also reduced.
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