Adenotonsillectomy for childhood obstructive sleep apnoea reduces thoraco-abdominal asynchrony but spontaneous apnoea−hypopnoea index normalisation does not

Associations of respiratory mechanic instability with respiratory parameters in pediatric patients with obstructive sleep apnea syndrome

OBJECTIVES

This study aimed to identify the effectiveness of respiratory mechanic instability (RMI) in the diagnosis of pediatric obstructive sleep apnea syndrome (OSAS). We sought to evaluate the correlations of RMI with sleep-related parameters and determine the effectiveness of using RMI for diagnosing OSAS in children.

METHODS

Children who underwent polysomnography (PSG) for various reasons were enrolled in this study. Patients' clinical and PSG data at two university hospitals were reviewed retrospectively. During PSG, RMI parameters were automatically calculated according to the phase relationship between thoracic and abdominal movement signals.

RESULTS

Among 263 children who underwent PSG, 183 (70.4%) were diagnosed with OSAS (apnea-hypopnea index [AHI] ≥ 1). RMI parameters were higher in the OSAS group than in the control group. They also tended to increase with disease severity. RMI scores were well correlated with respiratory parameters, showing a stronger correlation in those with moderate or severe OSAS without central apnea. Areas under the receiver operating characteristics curves (AUROCs) of RMI indicators were over 0.65. The percentage of RMI in stage duration showed the highest value of the AUROCs.

CONCLUSION

Paradoxical thoraco-abdominal movement assessed by RMI provides additional information. It may be useful in diagnosing OSAS in children.

Secondary Analyses of the Childhood Adenotonsillectomy Trial: A Narrative Review

Importance

Adenotonsillectomy, performed for approximately 500 000 children annually in the US alone, is the first line of treatment of pediatric obstructive sleep apnea (OSA). The Childhood Adenotonsillectomy Trial (CHAT), the first randomized clinical trial to test the efficacy of adenotonsillectomy, compared the management of pediatric nonsevere OSA by early adenotonsillectomy (eAT) vs watchful waiting with supportive care. Since the publication of the primary article in 2013, the CHAT study data set were made available via the National Sleep Research Resource, which allowed researchers to address a range of additional clinical questions relevant to the care of children with OSA. This review focuses on secondary analyses associated with the CHAT data set as grouped by the outcome of interest.

Observations

The results of most secondary analyses suggest that children who underwent eAT experienced the greatest improvements in symptom burden, sleepiness, parent-reported behavior, and quality of life. Changes in other domains, such as cognition, cardiovascular physiology, and metabolic indicators, were modest and selective. The associations between most treatment outcomes and polysomnographic parameters were weak. Symptoms were poor predictors of OSA severity. The results from these secondary analyses benefitted from the rigor of multicenter design and centralized polysomnography interpretation in CHAT. However, the exclusion of younger preschool-aged children and children with primary snoring limited the generalizability of findings. In addition, because caregivers were not masked, some of the parent-reported outcomes may have been inflated.

Conclusions and Relevance

The results of this narrative review suggest that CHAT provides a model for future OSA-related studies in children for design, conduct, and subsequent reuse of the study data set, and its findings have advanced our understanding of the pathophysiology and management of pediatric nonsevere OSA. Directions for future research include whether the findings from this landmark study are generalizable to younger children and children with primary snoring and severe OSA. Similar studies may help address practice variability associated with pediatric OSA and help identify children who are most likely to benefit from undergoing eAT.

Utilisation of machine learning to predict surgical candidates for the treatment of childhood upper airway obstruction

OBJECTIVE

To investigate the effect of adenotonsillectomy on OSAS symptoms based on a data-driven approach and thereby identify criteria that may help avoid unnecessary surgery in children with OSAS.

METHODS

In 323 children enrolled in the Childhood Adenotonsillectomy Trial, randomised to undergo either early adenotonsillectomy (eAT; N = 165) or a strategy of watchful waiting with supportive care (WWSC; N = 158), the apnea-hypopnea index, heart period pattern dynamics, and thoraco-abdominal asynchrony measurements from overnight polysomnography (PSG) were measured. Using machine learning, all children were classified into one of two different clusters based on those features. The cluster transitions between follow-up and baseline PSG were investigated for each to predict those children who recovered spontaneously, following surgery and those who did not benefit from surgery.

RESULTS

The two clusters showed significant differences in OSAS symptoms, where children assigned in cluster A had fewer physiological and neurophysiological symptoms than cluster B. Whilst the majority of children were assigned to cluster A, those children who underwent surgery were more likely to stay in cluster A after seven months. Those children who were in cluster B at baseline PSG were more likely to have their symptoms reversed via surgery. Children who were assigned to cluster B at both baseline and 7 months after surgery had significantly higher end-tidal carbon dioxide at baseline. Children who spontaneously changed from cluster B to A presented highly problematic ratings in behaviour and emotional regulation at baseline.

CONCLUSIONS

Data-driven analysis demonstrated that AT helps to reverse and to prevent the worsening of the pathophysiological symptoms in children with OSAS. Multiple pathophysiological markers used with machine learning can capture more comprehensive information on childhood OSAS. Children with mild physiological and neurophysiological symptoms could avoid AT, and children who have UAO symptoms post AT may have sleep-related hypoventilation disease which requires further investigation. Furthermore, the findings may help surgeons more accurately predict children on whom they should perform AT.

Top 100 influential manuscripts in obstructive sleep apnea: a bibliometric analysis

OBJECTIVE

This study aimed to explore the characteristics of the top 100 influential manuscripts on obstructive sleep apnea (OSA).

METHODS

All manuscripts in English were searched from the Thomson Reuters Web of Science database by using OSA-related terms and ranked based on citation frequency. The top 100 influential manuscripts were selected and further analyzed by author, subject, journal, year of publication, country of origin, and institution.

RESULTS

A total of 42,878 manuscripts were searched from the Web of Science. The top 100 influential manuscripts were published from 2005 to 2017, with a total citation frequency of 38,463 and a median citation frequency of 303 (range: from 210 to 2, 707). The American Journal of Respiratory and Critical Care Medicine published the largest number of manuscripts from the top 100 (n = 18; 5340 citations), followed by Sleep (n = 11; 3516 citations) and Chest (n = 7; 1784 citations). The most cited manuscript (Marin, J.M et al., Lancet 2005; 2707 citations) mainly analyzed long-term cardiovascular outcomes in men with OSA with/without continuous positive airway pressure. The most prevalent subject was associated diseases (n = 41), followed by treatments (n = 40). Most of the manuscripts were original articles (n = 63) based on observational clinical studies and published from American institutions (n = 60).

CONCLUSIONS

Our study identified the top 100 influential manuscripts on OSA and provides insights into the characteristics of the most highly cited manuscripts to improve our understanding and management of OSA.

Effect of adenotonsillectomy for childhood obstructive sleep apnea on nocturnal heart rate patterns

Study Objectives

To assess the effect of adenotonsillectomy for relieving obstructive sleep apnea syndrome (OSAS) symptoms in children on cardiac autonomic modulation.

Methods

In 354 children enrolled in the Childhood Adenotonsillectomy Trial, randomized to undergo either early adenotonsillectomy (eAT; N = 181) or a strategy of watchful waiting with supportive care (WWSC; N = 173), nocturnal heart rate control was analyzed during quiet, event-free sleep at baseline and at 7 months using overnight polysomnography (PSG). The relative frequency of patterns indicating monotonous changes in heart rate was quantified.

Results

Children who underwent eAT demonstrated a significantly greater reduction in heart rate patterns postsurgery than the WWSC group. On assessing those heart rate patterns regarding normalization of clinical PSG, heart patterns were reduced to a similar level in both groups. In children whose AHI normalized spontaneously, heart rate patterns were already significantly less frequent at baseline, suggesting that upper airway obstruction was milder in this group at the outset.

Conclusions

Adenotonsillectomy reduces monotonous heart rate patterns throughout quiet event-free sleep, reflecting a reduction in cardiac autonomic modulation. Heart rate pattern analysis may help quantifying the effect of OSAS on autonomic nervous system activity in children. Clinical Trial Registration: The study was registered at Clinicaltrials.gov (#NCT00560859).

A Method for Estimating Pulse Wave Amplitude Variability in children with Sleep Disordered Breathing

Sleep disordered breathing (SDB) is a common pediatric disorder, which results in increasing respiratory workload during sleep, restless night time sleep and excessive daytime sleepiness. It has significant negative effects on children with SDB on their physical growth and cognitive related developments. Chronic autonomic activation was suggested to be one of the possible key drivers causing cardiovascular structural changes in SDB children and increasing the risk of developing cardiovascular disease in their future. The aim of this study was to investigate the effect of SDB on autonomic activation changes in children, by analyzing the pulse wave amplitude (PWA) dynamics using a simple envelope estimation method extracting PWA from PPG signal.Children with SDB (n = 40) showed a significantly a wider dynamic distribution in PWA compare to matched controls (n = 40), which suggests a higher and stronger level of autonomic response in SDB children.In conclusion, the PWA dynamic is altered in children with SDB during sleep and indicate changes in autonomic activation.

Persistent respiratory effort after adenotonsillectomy in children with sleep-disordered breathing

OBJECTIVES

Adenotonsillectomy (AT) markedly improves but does not necessarily normalize polysomnographic findings in children with adenotonsillar hypertrophy and related sleep-disordered breathing (SDB). Adenotonsillectomy efficacy should be evaluated by follow-up polysomnography (PSG), but this method may underestimate persistent respiratory effort (RE). Mandibular movement (MMas) monitoring is an innovative measurement that readily identifies RE during upper airway obstruction. We hypothesized that MMas indices would decrease in parallel of PSG indices and that children with persistent RE more reliably could be identified with MMas.

METHODS

Twenty-five children (3-12 years of age) with SDB were enrolled in this individual prospective-cohort study. Polysomnography was supplemented with a midsagittal movement magnetic sensor that measured MMas during each respiratory cycle before and > 3 months after AT.

RESULTS

Adenotonsillectomy significantly improved PSG indices, except for RE-related arousals (RERA). Mandibular movement index changes after AT significantly were correlated with corresponding decreases in sleep apnea-hypopnea index (AHI) and O₂ desaturation index (ODI) (Spearman's rho = 0.978 and 0.922, respectively), whereas changes in MMas duration significantly were associated with both RERA duration (rho = 0.475, P = 0.017) and index (rho = 0.564, P = 0.003). Conditional multivariate analysis showed that both AHI and RERA significantly contributed to the variance of MMas index after AT (P = 0.0003 and 0.0005, respectively), whereas MMas duration consistently was related to the duration of RERA regardless of AT.

CONCLUSION

Adenotonsillectomy significantly reduced AHI. However, persistent RERA were apparent in a significant proportion of children, and this was reflected by the remaining abnormal MMas pattern. Follow-up of children after AT can be recommended and readily achieved by monitoring MMas to identify persistent RE.

LEVEL OF EVIDENCE

4. Laryngoscope, 128:1230-1237, 2018.