Increased thoracoabdominal asynchrony during breathing periods free of discretely scored obstructive events in children with upper airway obstruction

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.

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.

Adenotonsillectomy for paediatric sleep disordered breathing in Australia and New Zealand

AIMS

To review the contributions of Australian and New Zealand research on adenotonsillectomy for the treatment of symptoms of obstructed breathing during sleep (sleep disordered breathing, SDB) in children.

METHODS

A search of the scientific literature was conducted using the MEDLINE (Ovid), PubMed and Scopus databases in August 2020. The following search string was used: (tonsillectomy OR adenoidectomy OR adenotonsillectomy) AND (paediatric OR child) AND (Australia OR New Zealand). A focused internet search was additionally conducted on Google to identify grey literature.

RESULTS

Researchers from Australia and New Zealand have made important contributions to the understanding and improvement of adenotonsillectomy (AT), including its epidemiology, cost, surgical techniques and peri-operative safety. Rates of AT have fluctuated over the years, becoming the most common paediatric surgery today, with SDB becoming the most common indication. Research in Australia and New Zealand has also focussed on the impact of AT on quality of life, and behaviour, neurocognition and cardiovascular sequelae.

CONCLUSIONS

Australian and New Zealand researchers have played a significant role in understanding the epidemiology and improving the safety of AT. There are promising directions in research still to come, including better understanding of the reasons for geographical variation in surgery rates, developing more efficient pre-operative risk assessment tools and alternative treatment options for mild OSA.

Increased Platelet Aggregation in Children and Adolescents with Sleep-disordered Breathing

Rationale: Sleep-disordered breathing (SDB) is associated with increased vascular resistance in children and adults. Persistent increased vascular resistance damages vascular endothelial cells-a marker of which is increased platelet activation.Objectives: This study compared whole-blood impedance platelet aggregation in children with clinically diagnosed SDB warranting adenotonsillectomy and healthy control subjects.Methods: Thirty children who had SDB warranting intervention clinically diagnosed by experienced pediatric otolaryngologists were recruited from adenotonsillectomy waitlists, and 20 healthy children from the community underwent overnight polysomnography to determine SDB severity (obstructive apnea-hypopnea index). Snoring frequency was collected from parents. In the morning, a fasting blood sample was taken, and whole-blood platelet aggregation was measured.Measurements and Main Results: Children with SDB exhibited increased platelet aggregation to TRAP (thrombin receptor-activating peptide) (children with SDB = 114.8 aggregation units [AU] vs. control subjects = 98.0 AU; P < 0.05) and COL antibody (96.7 vs. 82.2 AU; P < 0.05) and an increased trend in ADP antibody (82.3 vs. 69.2 AU; P < 0.07) but not aspirin dialuminate (82.1 vs. 79.5 AU; P > 0.05). No significant association was observed between either the obstructive apnea-hypopnea index and any aggregation parameter, but parental report of snoring was positively associated with TRAP aggregation (Kendall's τ-c = 0.23; P < 0.05).Conclusions: The finding of increased platelet aggregation is consistent with endothelial damage. This suggests that the profile of cardiovascular changes noted in adults with SDB may also occur in children with SDB.

Consequences of paediatric sleep disordered breathing: contributions from Australian and New Zealand investigators

AIMS

To highlight the contributions of Australian and New Zealand researchers to the identification of the consequences of paediatric sleep disordered breathing (SDB).

METHODS

A search was conducted in PubMed using the terms "sleep disordered breathing" "child" and "Australia or New Zealand". All abstracts were reviewed and those which focused on the consequences of SDB have been included.

RESULTS

Australasian research into the consequences of SDB has grown exponentially over the last 35 years. SDB has significant adverse consequences for quality of life, behaviour, neurocognition and the cardiovascular system and the Australasian research studies investigating these are summarised.

CONCLUSIONS

Australian and New Zealand researchers have played a significant role in understanding the consequences of paediatric SDB and the mechanisms which underpin these. The research conducted "Downunder" has led the world in this field of research and will continue to provide evidence to improve the lives of children not only in Australasia but around the world.

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).

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

The efficacy of adenotonsillectomy for treating obstructive sleep apnoea syndrome (OSAS) in children has been established, but its precise effects on inspiratory effort are not well documented.

In 353 children enrolled in the Childhood Adenotonsillectomy Trial, randomised to undergo either early adenotonsillectomy (n=182) or a strategy of watchful waiting with supportive care (WWSC) (n=171), thoraco-abdominal asynchrony (TAA) was analysed during quiet, non-apnoeic and non-hypopnoeic breathing during sleep at baseline and at 7 months using overnight polysomnography.

Children who underwent early adenotonsillectomy demonstrated a reduction in TAA post-surgery while the WWSC arm showed no change. On assessing TAA with regard to normalisation of clinical polysomnography findings at follow-up, TAA was reduced in children who had surgical resolution of OSAS (based on apnoea–hypopnoea index), but not in children who displayed spontaneous normalisation of apnoea–hypopnoea index. In the latter group, TAA was inversely correlated with quality of life.

We conclude that adenotonsillectomy reduces TAA during quiet sleep. Monitoring of instantaneous TAA may yield additional insight in the dynamic changes of inspiratory effort. In combination with traditional indices of obstruction, TAA may more accurately characterise the degree of sleep-disordered breathing in children.