Research News: Obstructive Sleep Apnea in Children Mary W. Stewart, PhD, RN PEDIATRIC OBESITY IS a global problem and gives rise to serious health concerns. Obese children are at greater risk for obstructive sleep apnea (OSA). The traditional surgical intervention for children with OSA has been tonsillectomy and adenoidectomy (T&A). However, outcomes are less clear when the children undergoing this treatment are obese. Because of the ever-growing body of scientific literature, systematic reviews and meta-analyses have become a valid way to synthesize findings from multiple studies to inform best practice. In contrast to narrative reviews, systematic reviews follow a prescribed method to search and cull existing publications in response to a pre-determined question. A meta-analysis may follow the systematic review to statistically measure variances and effect size. The following describes a systematic review and meta-analysis of polysomnographic findings of children who had T&As for OSA. The research team was comprised of public health physicians and physician researchers representing six institutions in Taiwan. At present, the article has undergone full peer review and has been accepted for publication. Polysomnographic Findings after Adenotonsillectomy for Obstructive Sleep Apnea in Obese and Non-Obese Children: A Systematic Review and Meta-Analysis by Lee CH, Hsu WC, Chang WH, Lin MT, Kang KT. Clinical Otolaryngology. doi: 10.1111/coa.12549. Mary W. Stewart, PhD, RN, Professor and Director of PhD Program, and Director of Accreditation, School of Nursing, University of Mississippi Medical Center, Jackson, MS. Conflict of interest: None to report. Address correspondence to Mary W. Stewart, School of Nursing, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216-4505; e-mail address: [email protected]
. Ó 2016 by American Society of PeriAnesthesia Nurses 1089-9472/$36.00 http://dx.doi.org/10.1016/j.jopan.2015.11.007
Journal of PeriAnesthesia Nursing, Vol 31, No 1 (February), 2016: pp 103-105
Background and Purpose Polysomnography (PSG) is used to diagnosis and determine efficacy of treatment for OSA in children. Once diagnosed with pediatric OSA, a T&A is routinely scheduled. Although PSG includes several parameters, the apnea-hypopnea index (AHI) is the one measure often cited to verify a successful surgical outcome. Previous studies have used the AHI to define the cure rate of OSA. However, earlier systematic reviews and meta-analyses have reported varying success rates using the AHI. To date, no thorough review or analysis had been done looking at postoperative changes in all PSG parameters in this population. Pediatric obesity seems to have complicated the landscape. It is not clear how obese children with OSA compare with nonobese children with OSA in terms of surgical success after T&A for OSA. Therefore, the purpose of this study was twofold: (1) to identify changes in multiple sleep parameters after T&A for treatment of pediatric OSA and (2) to compare outcomes of treatment between the obese and nonobese children after T&A for OSA.
Method and Analysis Consistent with a systematic review, the authors clearly outlined their study methodology. First, they identified the search terms, databases to be searched, and publication dates. Search terms included the following:
Sleep apnea OSA Obstructive sleep apnea Sleep apnea syndromes Tonsillectomy Adenoidectomy Adenotonsillectomy Surgery Infant
MARY W. STEWART
Child Adolescent Humans PubMed, MEDLINE, Embase, and the Cochrane databases were searched using these terms. Note that PubMed is the online version of Index Medicus and provides free access to MEDLINE (the leading bibliographic database of the US National Library of Medicine) as well as links to related citations. Embase is Elsevier’s broad biomedical research electronic database that also includes articles on drugs, medical devices, basic science, and other subjects germane to clinical medicine. The Cochrane database, one initiative of the Cochrane Library, houses systematic reviews. Only articles published between January 1, 1997 and July 1, 2014 were included in the analysis. The authors identified which researchers were involved with the different aspects of the study and revealed no conflicts of interest.
3. associations between OSA severity, obesity, and postoperative AHI were studied; and 4. PSG parameters of a control group were compared with those of children with OSA postoperatively.
Results Articles ranged in quality from three to nine (on a 0 to 9 scale), with a mean score of 6. The time of follow-up after surgery varied among the studies; therefore, the weight of the children was assessed at different times. AHI measures represented ‘‘cure’’ of OSA, but the AHI scores ranged from one to five events per hour across the 51 studies. Sample sizes in the studies ranged from 10 to 578 children. Only one randomized controlled trial was included; others were retrospective observational or prospective nonrandomized studies. Comparison of PSG Parameters
Database searching identified 2,901 articles. After duplicates were removed, the researchers screened 1,103 articles. Of those 923 were excluded as irrelevant. Therefore, 180 full-text articles were assessed for study eligibility. Inclusion criteria were as follows: (1) children younger than 18 years, (2) T&A surgery, (3) preoperative PSG confirming OSA, and (4) postoperative PSG. A body mass index (BMI) in the 95th percentile or higher for the child’s age and gender defined obesity. Studies that involved complicated surgeries (beyond T&A) or patients (those with cognitive deficits, genetic disorders, craniofacial abnormalities, or neuromuscular disease) were excluded from the analysis. Of the 180 articles reviewed for eligibility, 129 were excluded: 5 were not OSA studies, 11 involved adult subjects, 51 lacked interventions, 48 had no PSG data, 9 were complicated cases, and 5 involved more than T&A. Therefore, 51 studies were included in the final analysis. Quality of studies was ranked on a scale of 0 (lowest) to 9 (highest). The statistical analysis addressed four major aspects: 1. All PSG parameters were compared for net postoperative changes; 2. changes in means and overall success for obese vs nonobese children were compared;
PSG evaluated total sleep time, sleep latency, sleep architecture, sleep efficiency, oxygen saturation, respiratory events, arousal index, carbon dioxide saturation, and overall success rate. Sleep time and sleep latency did not differ significantly before and after surgery. Some improvements in sleep architecture (eg, duration of rapid eye movement) were noted, and sleep efficiency increased after surgery. Oxygen saturation levels improved. Respiratory events noted in PSG are most often used to diagnose OSA. Of those events, AHI and other indexes were frequently reported in the studies analyzed. The mean change in AHI decreased by 12.4 events per hour after surgery. The arousal index represents three different indexes; all three improved significantly after surgery. Some improvement was seen in the measures of carbon dioxide saturation. Last, the success rate was estimated at 51% for AHI , 1 per hour after surgery and 81% for AHI , 5. Comparison of Obese vs Nonobese Children Researchers found a significantly different effect size of AHI when comparing the obese and nonobese groups. Among three groups: obese, nonobese, and combined (both obese and nonobese in sample) in studies using AHI , 1, the
success rates were 34% (obese), 49% (nonobese), and 56% (combined). In studies using AHI , 5, the success rates were 61% (obese), 87% (nonobese), and 84% (combined). The difference between the obese and nonobese groups in studies using the higher AHI was significantly lower for the nonobese groups. Factors Affecting Postoperative AHI Postoperative persistent OSA has been determined by obesity and AHI before surgery. These researchers looked at correlations between AHI before and after surgery as well as BMI. They found positive relationships between preoperative AHI and postoperative AHI as well as between BMI and postoperative AHI. OSA After Surgery Children with OSA were assessed for complete normalization of sleep parameters by analyzing PSG data of those children with a group of normal children. The normal children were nonsnoring and had AHI , 1. Children with OSA retained a higher AHI score after surgery and lower saturation levels compared with the normal children.
Conclusions This study represents the first to analyze changes in all PSG parameters and outcomes of T&A for children (obese and nonobese) with OSA. The researchers attended to detail and potential bias throughout the planning, conducting, and analysis of the study. A comprehensive and thorough look at these variables adds new information to the body of knowledge. With an international spotlight on childhood obesity, and a fore knowledge of comorbidities of obesity, weight reduction is a worthy consideration for children with OSA. Looking at PSG parameters beyond the AHI showed that children’s sleep quality and depth did improve after T&A. However, other clinical vari-
ables of influence should be considered in future research. Through this meta-analysis, the data indicated that obese children and preoperative AHI are related to residual OSA postoperatively. Also, complete normalization of sleep may not occur for children with OSA. The AHI change in this study was 12.4 events/hour, similar to previous analyses. Here, the overall success rate was seen in 51% of the children compared with previous studies that showed success rates from 59.8% to 82.9%. The prevalence of pediatric obesity and OSA is very serious. Although the researchers statistically controlled for heterogeneity of the studies under scrutiny, variations in demographics may introduce bias and affect results. Most studies were observational or quasi-experimental and did not include a control group. The limitations of the 51 articles included in this meta-analysis must also be considered in interpreting the findings.
Perianesthesia Nursing Implications Children represent a vulnerable population. Research with children involves a myriad of ethical considerations. Addressing these and other potential risks requires careful planning and substantial justification behind the research question. A systematic review and meta-analysis is one way to take a wider view of the evidence without recruiting new subjects. We may have existing data, such as these 51 studies, that can help answer secondary questions to improve our care. Perianesthesia nurses will continue to see T&A as the first line of treatment for OSA in children. However, we now realize that incidence of cure and improvement in sleep parameters vary, with obese children at higher risk. Nurses are in a position to advocate for postoperative PSG for these patients. Additionally, we can bring attention to the special needs of obese children and their caregivers before and after surgical intervention.