Weight Status, Autonomic Function, and Systemic Inflammation in Children with Obstructive Sleep Apnea

Children with obstructive sleep apnea (OSA) frequently experience chronic low-grade systemic inflammation, with the inflammasome playing a central role in OSA. This cross-sectional study evaluated the relationship between weight status, autonomic function, and systemic inflammation in a cohort of 55 children with OSA, predominantly boys (78%) with an average age of 7.4 ± 2.2 years and an apnea-hypopnea index of 14.12 ± 17.05 events/hour. Measurements were taken of body mass index (BMI), sleep heart-rate variability, morning circulatory levels of interleukin-1β, interleukin-1 receptor antagonist, and interleukin-6, and tumor necrosis factor-α, anthropometry, and polysomnography. Multiple linear regression modeling showed that an apnea-hypopnea index was significantly associated with BMI, the standard deviation of successive differences between normal-to-normal intervals during N3 sleep, and the proportion of normal-to-normal interval pairs differing by more than 50 ms during rapid-eye-movement sleep. A moderated mediation model revealed that interleukin-1 receptor antagonist levels mediated the association between BMI and interleukin-6 levels, with sympathovagal balance during N3 sleep and minimum blood oxygen saturation further moderating these relationships. This study highlights the complex relationships between BMI, polysomnographic parameters, sleep heart-rate-variability metrics, and inflammatory markers in children with OSA, underlining the importance of weight management in this context.

Modelling metabolic performance in paediatric obstructive sleep disordered breathing: A case-control study

Paediatric obstructive sleep disordered breathing (OSDB) has a considerable impact on cardiovascular physiology, but the consequences on children's basal metabolism and response to exercise are far from being known. The objective was to propose model estimations for paediatric OSDB metabolism at rest and during exercise. A retrospective case-control analysis of data from children submitted to otorhinolaryngology surgery was performed. The heart rate (HR) was measured, while oxygen consumption (VO2) and energy expenditure (EE) at rest and during exercise were obtained using predictive equations. The results for the patients with OSDB were compared with controls. A total of 1256 children were included. A total of 449 (35.7%) had OSDB. The patients with OSDB showed a significantly higher resting heart rate (94.55 ± 15.061 bpm in OSDB vs. 92.41 ± 15.332 bpm in no-OSDB, p = 0.041). The children with OSDB showed a higher VO2 at rest (13.49 ± 6.02 mL min-1kg-1 in OSDB vs. 11.55 ± 6.83 mL min-1kg-1 in no-OSDB, p = 0.004) and a higher EE at rest (67.5 ± 30.10 cal min-1kg-1 in OSDB vs. 57.8 + 34.15 cal min-1kg-1 in no-OSDB, p = 0.004). At maximal exercise, patients with OSDB showed a lower VO2max (33.25 ± 5.82 mL min-1kg-1 in OSDB vs. 34.28 ± 6.71 in no-OSDB, p = 0.008) and a lower EE (166.3 ± 29.11 cal min-1kg-1 in OSDB vs. 171.4 ± 33.53 cal min-1kg-1 in no-OSDB, p = 0.008). The VO2/EE increment with exercise (Δ VO2 and Δ EE) was lower in OSDB for all exercise intensities (p = 0.009). This model unveils the effect of paediatric OSDB on resting and exercise metabolism. Our findings support the higher basal metabolic rates, poorer fitness performance, and cardiovascular impairment found in children with OSDB.

Obstructive sleep apnea heterogeneity and autonomic function: a role for heart rate variability in therapy selection and efficacy monitoring

Obstructive sleep apnea is a highly prevalent sleep-related breathing disorder, resulting in a disturbed breathing pattern, changes in blood gases, abnormal autonomic regulation, metabolic fluctuation, poor neurocognitive performance, and increased cardiovascular risk. With broad inter-individual differences recognised in risk factors, clinical symptoms, gene expression, physiological characteristics, and health outcomes, various obstructive sleep apnea subtypes have been identified. Therapeutic efficacy and its impact on outcomes, particularly for cardiovascular consequences, may also vary depending on these features in obstructive sleep apnea. A number of interventions such as positive airway pressure therapies, oral appliance, surgical treatment, and pharmaceutical options are available in clinical practice. Selecting an effective obstructive sleep apnea treatment and therapy is a challenging medical decision due to obstructive sleep apnea heterogeneity and numerous treatment modalities. Thus, an objective marker for clinical evaluation is warranted to estimate the treatment response in patients with obstructive sleep apnea. Currently, while the Apnea-Hypopnea Index is used for severity assessment of obstructive sleep apnea and still considered a major guide to diagnosis and managements of obstructive sleep apnea, the Apnea-Hypopnea Index is not a robust marker of symptoms, function, or outcome improvement. Abnormal cardiac autonomic modulation can provide additional insight to better understand obstructive sleep apnea phenotyping. Heart rate variability is a reliable neurocardiac tool to assess altered autonomic function and can also provide cardiovascular information in obstructive sleep apnea. Beyond the Apnea-Hypopnea Index, this review aims to discuss the role of heart rate variability as an indicator and predictor of therapeutic efficacy to different modalities in order to optimise tailored treatment for obstructive sleep apnea.

Sleep disordered breathing improvement prevents worsening of autonomic dysfunction in children with Down syndrome

BACKGROUND

Resolution of sleep disordered breathing (SDB) in typically developing children normalises heart rate variability (HRV), a measure of autonomic control, to that of non-snoring controls. Children with Down Syndrome (DS) have dampened heart rate variability (HRV) but the effect of treatment is not known. To assess the effect of improvement of SDB on autonomic control we compared HRV in children with DS whose SDB improved over 2 y, to those whose SDB did not improve.

METHODS

24 children (3-19 y) had a baseline and follow-up polysomnographic study 2 y later. Improved SDB was defined as a reduction in obstructive apnea hypopnea index (OAHI) to ≤ 50% of baseline. Children were grouped into Improved (n = 12) and Unimproved (n = 12). Power spectral analysis of the ECG determined low frequency (LF), high frequency (HF) power and the LF/HF ratio. Seven children in the Improved and 2 in the Unimproved group were treated following the baseline study.

RESULTS

In the Unimproved group at follow-up, LF power was lower compared to baseline during N3 and Total Sleep (p < 0.05 for both). HF power was lower during REM (p < 0.05). HRV remained unchanged between studies in the Improved group.

CONCLUSION

Autonomic control worsened as indicated by lower LF and HF power in children whose SDB was not improved. In contrast, in those children with improved SDB, autonomic control remained the same, suggesting improvement in SDB severity prevents further worsening of autonomic control in children with DS.

Pediatric sleep apnea: Characterization of apneic events and sleep stages using heart rate variability

Heart rate variability (HRV) is modulated by sleep stages and apneic events. Previous studies in children compared classical HRV parameters during sleep stages between obstructive sleep apnea (OSA) and controls. However, HRV-based characterization incorporating both sleep stages and apneic events has not been conducted. Furthermore, recently proposed novel HRV OSA-specific parameters have not been evaluated. Therefore, the aim of this study was to characterize and compare classic and pediatric OSA-specific HRV parameters while including both sleep stages and apneic events. A total of 1610 electrocardiograms from the Childhood Adenotonsillectomy Trial (CHAT) database were split into 10-min segments to extract HRV parameters. Segments were characterized and grouped by sleep stage (wake, W; non-rapid eye movement, NREMS; and REMS) and presence of apneic events (under 1 apneic event per segment, e/s; 1-5 e/s; 5-10 e/s; and over 10 e/s). NREMS showed significant changes in HRV parameters as apneic event frequency increased, which were less marked in REMS. In both NREMS and REMS, power in BW2, a pediatric OSA-specific frequency domain, allowed for the optimal differentiation among segments. Moreover, in the absence of apneic events, another defined band, BWRes, resulted in best differentiation between sleep stages. The clinical usefulness of segment-based HRV characterization was then confirmed by two ensemble-learning models aimed at estimating apnea-hypopnea index and classifying sleep stages, respectively. We surmise that basal sympathetic activity during REMS may mask apneic events-induced sympathetic excitation, thus highlighting the importance of incorporating sleep stages as well as apneic events when evaluating HRV in pediatric OSA.

Using sleep heart rate variability to investigate the sleep quality in children with obstructive sleep apnea

Background

Obstructive sleep apnea (OSA) is associated with impaired sleep quality and autonomic dysfunction. Adenotonsillectomy significantly improves subjective and objective sleep quality in children with OSA. However, the postoperative changes in heart rate variability (HRV) indices (indicators of cardiac autonomic function) and their importance remain inconclusive in childhood OSA. This retrospective case series aimed to investigate the association of sleep HRV indices, total OSA-18 questionnaire score (a subjective indicator of sleep quality) and polysomnographic parameters (objective indicators of sleep quality), and effects of adenotonsillectomy on HRV indices, total OSA-18 questionnaire score and polysomnographic parameters in children with OSA.

Methods

Seventy-six children with OSA were included in baseline analysis, of whom 64 (84%) completed at least 3 months follow-up examinations after adenotonsillectomy and were included in outcome analysis. Associations between baseline variables, and relationships with treatment-related changes were examined.

Results

Multivariable linear regression models in the baseline analysis revealed independent relationships between tonsil size and obstructive apnea-hypopnea index (OAHI), adenoidal-nasopharyngeal ratio and very low frequency (VLF) power of HRV (an indicator of sympathetic activity), and normalized low frequency power (an indicator of sympathetic activity) and OAHI. The outcome analysis showed that adenotonsillectomy significantly improved standard deviation of all normal-to-normal intervals, and high frequency power, QoL (in terms of reduced total OSA-18 questionnaire score), OAHI and hypoxemia. Using a conceptual serial multiple mediation model, % change in OSA-18 questionnaire score and % change in VLF power serially mediated the relationships between change in tonsil size and % change in OAHI.

Conclusions

The improvement in OAHI after adenotonsillectomy was serially mediated by reductions in total OSA-18 questionnaire score and VLF power. These preliminary findings are novel and provide a direction for future research to investigate the effects of VLF power-guided interventions on childhood OSA.

Level of urinary catecholamine in children with Sleep Disordered Breathing: A systematic review and meta-analysis

OBJECTIVE

To compare the levels of different urinary catecholamines amongst paediatric patients with and without sleep-disordered breathing (SDB).

METHODS

Literature searches were conducted on PubMed and EMBASE until 25/06/2022. Inclusion criteria were original human studies, English language, paediatric subjects diagnosed with SDB/obstructive sleep apnoea (OSA). The quality of studies was assessed by the Newcastle-Ottawa Quality Assessment (NOSGEN). The registered number of this study on the International Prospective Register of Systematic Reviews (PROSPERO) is CRD42022332939. The main outcome measured was standardised mean difference (SMD) of urinary catecholamine between subjects with and without SDB, between those with and without OSA, and also between subjects with mild OSA and those with moderate/ severe OSA. Sensitivity analyses were performed to avoid bias.

RESULTS

9 studies (8 cross-sectional and 1 cohort study) with a total of 838 subjects, were included in the quantitative analysis. Urine level of noradrenaline was higher in patients with SDB, which included primary snoring (PS), when compared to controls: SMD = 0.86 (95%CI=0.32-1.41; I²=85%, P=0.002). The levels of urinary noradrenaline and adrenaline were higher in children with OSA when compared to controls: SMD = 1.45 (95%CI=0.91-2.00; I²=75%, P < 0.001); SMD = 1.84 (0.00-3.67; I²=97%, P=0.05). Urine level of noradrenaline was higher in subjects with moderate/severe OSA compared to the mild OSA: SMD = 0.55 (95%CI=0.10-1.00; I²=0%, P=0.02). Urinary dopamine was not associated with SDB regardless of severity.

CONCLUSIONS

Urinary noradrenaline was higher in all patients with SDB. Subjects with OSA, a more severe form of SDB, had higher urine levels of noradrenaline and adrenaline. Hence, noradrenaline and adrenaline may be markers of sympathetic overtone in patients with SDB and could potentially act as surrogate markers for SDB complications. Further studies are needed to assess this association.

Sleep-Disordered Breathing and Cardiovascular Disease in Children and Adolescents: A Scientific Statement From the American Heart Association

Obstructive sleep apnea (OSA) is a known risk factor for cardiovascular disease in adults. It is associated with incident systemic hypertension, arrhythmia, stroke, coronary artery disease, and heart failure. OSA is common in children and adolescents, but there has been less focus on OSA as a primary risk factor for cardiovascular disease in children and adolescents. This scientific statement summarizes what is known regarding the impact of sleep‐disordered breathing and, in particular, OSA on the cardiovascular health of children and adolescents. This statement highlights what is known regarding the impact of OSA on the risk for hypertension, arrhythmia, abnormal ventricular morphology, impaired ventricular contractility, and elevated right heart pressure among children and adolescents. This scientific statement also summarizes current best practices for the diagnosis and evaluation of cardiovascular disease–related complications of OSA in children and adolescents with sleep apnea and highlights potential future research in the area of sleep‐disordered breathing and cardiovascular health during childhood and adolescence.

Heart Rate Variability as a Potential Biomarker of Pediatric Obstructive Sleep Apnea Resolution

STUDY OBJECTIVES

Pediatric obstructive sleep apnea (OSA) affects cardiac autonomic regulation, altering heart rate variability (HRV). Although changes in classical HRV parameters occur after OSA treatment, they have not been evaluated as reporters of OSA resolution. Specific frequency bands (named BW1, BW2 and BWRes) have been recently identified in OSA. We hypothesized that changes with treatment in these spectral bands can reliably identify changes in OSA severity and reflect OSA resolution.

METHODS

404 OSA children (5-9.9 years) from the prospective Childhood Adenotonsillectomy Trial (CHAT) were included; 206 underwent early adenotonsillectomy (eAT), while 198 underwent watchful waiting with supportive care (WWSC). HRV changes from baseline to follow-up were computed for classical and OSA-related frequency bands. Causal mediation analysis was conducted to evaluate how treatment influences HRV through mediators such as OSA resolution and changes in disease severity. Disease resolution was initially assessed by considering only obstructive events, and was followed by adding central apneas to the analyses.

RESULTS

Treatment, regardless of eAT or WWSC, affects HRV activity, mainly in the specific frequency band BW2 (0.028-0.074 Hz). Furthermore, only changes in BW2 were specifically attributable to all OSA resolution mediators. HRV activity in BW2 also showed statistically significant differences between resolved and non-resolved OSA.

CONCLUSIONS

OSA treatment affects HRV activity in terms of change in severity and disease resolution, especially in OSA-related BW2 frequency band. This band allowed to differentiate HRV activity between children with and without resolution, so we propose BW2 as potential biomarker of pediatric OSA resolution.

The Different Facets of Heart Rate Variability in Obstructive Sleep Apnea

Obstructive sleep apnea (OSA), a heterogeneous and multifactorial sleep related breathing disorder with high prevalence, is a recognized risk factor for cardiovascular morbidity and mortality. Autonomic dysfunction leads to adverse cardiovascular outcomes in diverse pathways. Heart rate is a complex physiological process involving neurovisceral networks and relative regulatory mechanisms such as thermoregulation, renin-angiotensin-aldosterone mechanisms, and metabolic mechanisms. Heart rate variability (HRV) is considered as a reliable and non-invasive measure of autonomic modulation response and adaptation to endogenous and exogenous stimuli. HRV measures may add a new dimension to help understand the interplay between cardiac and nervous system involvement in OSA. The aim of this review is to introduce the various applications of HRV in different aspects of OSA to examine the impaired neuro-cardiac modulation. More specifically, the topics covered include: HRV time windows, sleep staging, arousal, sleepiness, hypoxia, mental illness, and mortality and morbidity. All of these aspects show pathways in the clinical implementation of HRV to screen, diagnose, classify, and predict patients as a reasonable and more convenient alternative to current measures.

Heart rate variability spectrum characteristics in children with sleep apnea

BACKGROUND

Classic spectral analysis of heart rate variability (HRV) in pediatric sleep apnea-hypopnea syndrome (SAHS) traditionally evaluates the very low frequency (VLF: 0-0.04 Hz), low frequency (LF: 0.04-0.15 Hz), and high frequency (HF: 0.15-0.40 Hz) bands. However, specific SAHS-related frequency bands have not been explored.

METHODS

One thousand seven hundred and thirty-eight HRV overnight recordings from two pediatric databases (0-13 years) were evaluated. The first one (981 children) served as training set to define new HRV pediatric SAHS-related frequency bands. The associated relative power (RP) were computed in the test set, the Childhood Adenotonsillectomy Trial database (CHAT, 757 children). Their relationships with polysomnographic variables and diagnostic ability were assessed.

RESULTS

Two new specific spectral bands of pediatric SAHS within 0-0.15 Hz were related to duration of apneic events, number of awakenings, and wakefulness after sleep onset (WASO), while an adaptive individual-specific new band from HF was related to oxyhemoglobin desaturations, arousals, and WASO. Furthermore, these new spectral bands showed improved diagnostic ability than classic HRV.

CONCLUSIONS

Novel spectral bands provide improved characterization of pediatric SAHS. These findings may pioneer a better understanding of the effects of SAHS on cardiac function and potentially serve as detection biomarkers.

IMPACT

New specific heart rate variability (HRV) spectral bands are identified and characterized as potential biomarkers in pediatric sleep apnea. Spectral band BW1 (0.001-0.005 Hz) is related to macro sleep disruptions. Spectral band BW2 (0.028-0.074 Hz) is related to the duration of apneic events. An adaptive spectral band within the respiratory range, termed ABW3, is related to oxygen desaturations. The individual and collective diagnostic ability of these novel spectral bands outperforms classic HRV bands.

Cross-sectional case-control study of the relationships between pharyngeal compliance and heart rate variability indices in childhood obstructive sleep apnoea

A combination of noradrenergic and antimuscarinic agents reduces the apnea-hypopnea index (AHI) in adult patients with obstructive sleep apnoea (OSA) via reduced upper airway collapsibility, suggesting that a shift in the sympathovagal balance improves OSA. The objectives of our present case-control study were to assess heart rate variability (HRV) indices in the stages of sleep in children with and without OSA to evaluate OSA-induced sleep HRV modifications and to assess whether increased collapsibility measured during wakefulness is associated with reduced sympathetic activity during non-rapid eye movement (NREM) sleep. Three groups of 15 children were matched by sex, age, z-score of body mass index and ethnicity: non-OSA (obstructive AHI [OAHI] <2 events/hr), mild (OAHI ≥2 to <5 events/hr) or moderate-severe (OAHI ≥5 events/hr) OSA. Pharyngeal compliance was measured during wakefulness using acoustic pharyngometry. HRV indices (time and frequency domain variables) were calculated on 5-min electrocardiography recordings from polysomnography during wakefulness, NREM and REM sleep in periods free of any event. As compared to children without OSA, those with OSA (n = 30) were characterised by increased compliance and no physiological parasympathetic tone increase in REM sleep. Children with increased pharyngeal compliance (n = 21) had a higher OAHI due to higher AHI in NREM sleep, whereas their sympathetic tone was lower than that of those with normal compliance (n = 24). In conclusion, children with increased pharyngeal compliance exhibit decreased sympathetic tone associated with increased AHI in NREM sleep. Therapeutics directed at sympathovagal balance modifications should be tested in childhood OSA.

Attenuated heart rate recovery in children and adolescents with obstructive sleep apnea syndrome

BACKGROUND

Autonomic dysfunction is a key trait in the development of obstructive sleep apnea syndrome (OSAS) in adults. However, few similar studies focused on children and adolescents. We investigated if there was any association between heart rate recovery (HRR) and the severity of OSAS in children and adolescents.

METHODS

A total of 161 subjects were included: 87 healthy controls, 35 mild OSAS patients (M-OSAS) and 39 moderate-severe OSAS (M-S-OSAS) patients. Clinical parameters, cardiopulmonary exercise test (CPET) indexes including HRR and polysomnographic records including apnea-hypopnea index (AHI) were compared among the three groups. Pearson correlation analysis and multivariable linear regression analysis were used to detect the relationship between HRR and polysomnographic parameters.

RESULTS

HRR values in either the OSAS group were lower than those of the control group, and the values in the M-S OSAS group were even lower than those of the M-OSAS group (P < 0.05). Correlation analysis showed that HRR was inversely correlated with AHI (r = -0.190, P < 0.01). Moreover, multivariable linear regression analyses showed the association between HRR and AHI was significant (β = 0.174, P < 0.01).

CONCLUSIONS

HRR was closely associated with OSAS severity, which suggested that HRR might be a promising index for risk stratification and clinical management in children and adolescents with OSAS.

IMPACT

Heart rate recovery (HRR), a noninvasive and reliable index of automatic nervous system, is closely associated with the severity of obstructive sleep apnea syndrome (OSAS) in children and adolescents. To our knowledge, our study was the first study in China focusing on evaluating the role of HRR in children with OSAS. We found HRR was closely associated with OSAS severity in children and adolescents, and it suggested that HRR might be a promising index for risk stratification and clinical management in children and adolescents with OSAS.

Plasma Homocysteine and Autonomic Nervous Dysfunction: Association and Clinical Relevance in OSAS

Objective

Elevated plasma homocysteine (Hcy) is an independent risk factor for cardiovascular diseases, but the precise mechanism of Hcy in cardiovascular disease remains elusive. This study is aimed at evaluating the association between Hcy levels and autonomic nervous system and at investigating their clinical relevance in obstructive sleep apnea syndrome (OSAS).

Methods

A total of 191 subjects with OSAS were enrolled for this cross-sectional study. Heart rate variability (HRV) represents the status of the autonomic nervous system and is a well-known index that allows studying the autonomic modulation. HRV and polysomnography parameters were collected based on Holter monitors and polysomnography system. The software computed all the basic HRV parameters including SDANN, SDNN and pNN50. Correlation analyses between Hcy and HRV parameters and echocardiographic parameters were performed.

Results

Compared with the mild-moderate OSAS group, the prevalence of male and smoking and Hcy levels were considerably higher in the severe OSAS group (P = 0.01, P = 0.02, and P = 0.01, respectively). Also, there were significant linear relationships between Hcy quartiles with the proportion of severe OSAS (P = 0.01 for the trend). Interesting, there is a negative linear correlation between SDANN and Hcy quartiles (P = 0.02 for the trend). Spearman's correlation analysis showed a significant negative correlation between SDANN and Hcy levels (r = -0.17, P = 0.02). Interestingly, the relationship of it remains significant after adjustment for clinical covariates (r = -0.15, P = 0.04). However, echocardiographic parameters were not significantly correlated with Hcy or HRV parameters (all P > 0.05).

Conclusions

Elevated plasma Hcy level is linearly correlated with cardiac autonomic nervous function disorders in patients with OSAS.

Treatment-Related Changes in Heart Rate Variability in Children with Sleep Apnea

OBJECTIVE

Heart rate variability (HRV), a noninvasive indicator of autonomic regulation of cardiac rhythm, may represent the physiologic burden of obstructive sleep apnea (OSA). We hypothesized that the treatment-related effects of OSA on HRV in children are causally attributable to the improvement in OSA severity.

STUDY DESIGN

Secondary analysis of outcomes from the Childhood Adenotonsillectomy Trial (CHAT).

SETTING

Analysis of database.

SUBJECTS AND METHODS

Time- and frequency-domain HRV parameters along with polysomnographic (PSG) and demographic variables were obtained from the CHAT study, which compared early adenotonsillectomy (eAT) to watchful waiting (WW) in children with OSA. The relative contributions of PSG variables and covariates to each HRV parameter were quantified. The proportion of changes in HRV parameters causally attributable to changes in OSA severity, measured by the apnea-hypopnea index (AHI) and oxygen desaturation index (ODI), was estimated.

RESULTS

In total, 404 children aged 5 to 10 years were included. The median (interquartile range) age was 6 (3-9) years. The median body mass index percentile was 82 (53), 195 (48%) children were male, and 147 (36%) were African American. The average heart rate during PSG was the strongest independent predictor of each HRV parameter (P < .001). Although eAT resulted in statistically significant changes in the majority of HRV parameters, these effects were not causally attributable to treatment-related changes in AHI or ODI.

CONCLUSIONS

The average heart rate strongly modulates HRV in children with OSA. Although eAT results in discernible changes in HRV, it appears to not be causally attributable to specific treatment-related changes in AHI or ODI.

Nocturnal heart rate variability may be useful for determining the efficacy of mandibular advancement devices for obstructive sleep apnea

A mandibular advancement device (MAD) is recommended as an alternative therapy for obstructive sleep apnea (OSA), which effectively reduces the collapsibility of the upper airway during sleep by advancing the mandible. However, the effects of MAD therapy on cardiac autonomic modulation remain unclear. We evaluated the effects of MAD on nocturnal heart rate variability (HRV) in OSA. Anthropometric data, questionnaire results, and HRV parameters (evaluated using time domain and frequency domain methods) of 58 adult patients with OSA treated with MAD therapy were retrospectively reviewed. All patients underwent polysomnography at baseline and 3-month follow-up. The average normal-to-normal (NN) interval, standard deviation of the NN interval, low-frequency power in normalized units (LFnu), and high-frequency power in normalized units (HFnu) showed significant changes with MAD therapy. Based on the criteria for success (decrease in the apnea-hypopnea index by >50% and value <20/h), 34 and 24 patients were classified into the response and nonresponse groups, respectively. No differences in baseline characteristics were detected between groups, except for higher body mass index and lower minimal oxygen saturation in the nonresponse group. A subgroup analysis indicated that the average NN interval and HFnu significantly increased, and that Total power (TP), very low frequency, low frequency(LF), low frequency/high frequency and LFnu significantly decreased compared to baseline in the response group; however, no HRV changes were found in the nonresponse group. After adjusting for age, sex, and body mass index, the response group showed significant changes from baseline in TP and LF compared to the nonresponse group. Therefore, HRV may be useful for determining the efficacy of MAD therapy in OSA.

Assessing the need for adenotonsillectomy for sleep-disordered breathing in a community setting: A secondary outcome measures analysis of a randomized controlled study

OBJECTIVE

To assess whether children with sleep-disordered breathing (SDB) symptom severity above a certain level, measured by a validated questionnaire, improve after adenotonsillectomy (AT) compared to no intervention.

METHODS

Children with snoring and tonsillar hypertrophy (4 to 10-years old), who were candidates for AT, were randomly assigned to two evaluation sequences (baseline and 3-month follow-up): (a) evaluation immediately before AT and at 3 months postoperatively (AT group); or (b) evaluation at the initial visit and at the end of the usual 3-month waiting period for surgery (control group). Outcomes were (a) Pediatric Sleep Questionnaire sleep-related breathing disorder scale (PSQ-SRBD); (b) modified Epworth Sleepiness Scale (mESS); and (c) proportion of subjects achieving PSQ-SRBD <0.33 (low-risk for apnea-hypopnea index ≥5/h) if they had score ≥0.33 at baseline.

RESULTS

Sixty-eight children were assigned to the AT and 72 to the control group and two-thirds of them had PSQ-SRBD ≥0.33. The AT group experienced significantly larger improvement between follow-up and baseline than controls (between-group difference [95% CI] for PSQ-SRBD: -0.31 [-0.35 to -0.27]; and mESS: -2.76 [-3.63 to -1.90]; P < .001 for both). Children with baseline PSQ-SRBD ≥0.33 in the AT group had an eight-times higher probability of achieving PSQ-SRBD <0.33 at follow-up than controls with similar baseline score (risk ratio [95% CI]: 8.33 [3.92-17.54]; P < .001).

CONCLUSION

Among children with snoring, tonsillar hypertrophy, and clinical indications for AT, those with preoperative PSQ-SRBD score ≥0.33 show measurable clinical benefit postoperatively.

Association between snoring and heart rate variability in adolescents: effects of gender and insufficient sleep

PURPOSE

We explored the association between subjective snoring frequency and heart rate variability (HRV) in a healthy adolescent population.

METHODS

A total of 102 healthy adolescents were recruited from high schools in South Korea, and reported their sleep habits and snoring frequency. HRV was assessed to indirectly measure autonomic function. We assessed correlations between snoring frequency and HRV indices. We also investigated the effects of sex and behaviorally induced insufficient sleep syndrome (BISS) on the associations between HRV parameters and snoring frequency.

RESULTS

Overall, significant correlations were apparent between snoring frequency and HRV indices including the standard deviation of the normal-to-normal intervals (SDNN) and the low-frequency/high-frequency (LF/HF) ratio. Associations were more evident in males and those with BISS compared to females and those without BISS.

CONCLUSIONS

Our findings suggest that snoring changes autonomic nervous system (ANS) activity in adolescents; the changes are more dramatic in males and those with insufficient sleep.

OSA and Cardiovascular Risk in Pediatrics

OSA occurs in approximately 1% to 5% of children in the United States. Long-term cardiovascular risks associated with OSA in the adult population are well documented. Although changes in BP regulation occur in children with OSA, the pathways leading to chronic cardiovascular risks of OSA in children are less clear. Risk factors associated with cardiovascular disease in adult populations could carry the same future risk for children. It is imperative to determine whether known mechanisms of cardiovascular diseases in adults are like those that lead to pediatric disease. Early pathophysiologic changes may lead to a lifetime burden of cardiovascular disease and early mortality. With this perspective in mind, our review discusses pathways leading to cardiovascular pathology in children with OSA and provides a comprehensive overview of recent research findings related to cardiovascular sequelae in the pediatric population.

Sleep disordered breathing in children disrupts the maturation of autonomic control of heart rate and its association with cerebral oxygenation

KEY POINTS

Sleep disordered breathing (SDB) affects 4-11% of children and is associated with adverse neurocognitive, behavioural and cardiovascular outcomes, including reduced autonomic control. The relationship between heart rate variability (HRV; a measure of autonomic control) and age found in non-snoring control children was absent during sleep in children with SDB. Age significantly predicted increasing cerebral oxygenation during wake in non-snoring control children, whereas during sleep, HRV significantly predicted decreasing cerebral oxygenation. Cerebral oxygenation was not associated with either age or HRV in children with SDB during both wake and sleep. SDB significantly disrupts the normal maturation of autonomic control and the positive association between autonomic control and cerebral oxygenation found in non-snoring children, and we speculate that the dampened autonomic control exhibited by children with SDB may have an attenuating effect on cerebral autoregulation via the moderating influence of HRV on cerebral blood flow.

ABSTRACT

The repetitive episodes of hypoxia that are features of sleep disordered breathing (SDB) in children are associated with alterations in autonomic control of heart rate in an age-dependent manner. We aimed to relate heart rate variability (HRV) parameters to age and measures of cerebral oxygenation in children (3-12 years old) with SDB and non-snoring controls. Children (SDB, n = 117; controls, n = 42; 3-12 years) underwent overnight polysomnography. Total (TP), low- (LF) and high-frequency (HF) power, tissue oxygenation index (TOI) and fractional tissue oxygen extraction (FTOE) were analysed during wake and sleep. Pearson's correlations determined the association between age and HRV parameters, and multiple linear regressions between HRV, age and cerebral oxygenation parameters. During wake, age had a positive association with LF power, reflecting increased parasympathetic and sympathetic activity with increasing age for both control and SDB groups. This association was also evident during sleep in controls, but was absent in children with SDB. In controls, during wake TOI had a positive, and FTOE a negative association with age. During sleep, TP, LF and HF power were significant, negative determinants of TOI and positive determinants of FTOE. These associations were not seen in children with SDB during wake or sleep. SDB disrupts the normal maturation of the autonomic control of heart rate and the association between HRV and cerebral oxygenation exhibited by non-snoring control children of primary school age. These results highlight the impact SDB has on cardiovascular control and the potential impact on adverse cardiovascular outcomes.

Electrocardiographic variables in children with syndromic craniosynostosis and primary snoring to mild obstructive sleep apnea: significance of identifying respiratory arrhythmia during sleep

BACKGROUND

In the spectrum of children with symptomatic sleep disordered breathing (SDB), some individuals - such as those with upper airway resistance syndrome (UARS) - do not have abnormalities on polysomnography (PSG). In this study we have assessed whether assessment of respiratory arrhythmia (RA) and heart rate variability (HRV) analysis helps in management of children with syndromic craniosynostosis and none-to-mild obstructive sleep apnea (OSA).

METHODS

Prospective cohort study in children aged 1-18 years old with syndromic craniosynostosis. Children were selected for HRV analysis from the ECG if their obstructive apnea-hypopnea index (oAHI) was between zero and five per hour (ie, oAHI ≤5/hour). Subjects were divided into groups based on the presence or absence of respiratory arrhythmia (with or without RA respectively) using the electrocardiogram (ECG). The main analysis included studying the relationship between RA and HRV, symptoms, interventions, and sleep architecture.

RESULTS

We identified 42 patients with, at worst, mild OSA. We found higher parasympathetic control and higher total power in children with RA during the non-rapid eye movement (non-REM) sleep. Children with RA also have a relatively higher percentage of paradoxical breathing during non-REM sleep (P = 0.042). Intracranial hypertension was distributed equally between groups. Last, RA patients showed increased parasympathetic activity that further increased in non-REM sleep.

CONCLUSION

In syndromic craniosynostosis cases with SDB and PSG showing oAHI ≤5/hour, the presence of RA may indicate subsequent need for treatment interventions, and a trend toward higher occurrence of clinical symptoms. ECG analyses of HRV variables in subjects with RA demonstrate increased parasympathetic activity and total power. Such findings may add to the diagnosis of apparently asymptomatic children.

Success of Tonsillectomy for Obstructive Sleep Apnea in Children With Down Syndrome

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is common in children with Down syndrome (DS) and associated with significant morbidity. In the current study we examined polysomnographic outcomes of children with DS who underwent tonsillectomy.

METHODS

A retrospective chart review of children with DS who underwent a tonsillectomy between 2009-2015 was performed. All children had either a concurrent adenoidectomy or had previously underwent an adenoidectomy. Children with preoperative and postoperative polysomnograms within 6 months of surgery were included in the analysis. Preoperative OSA severity was categorized by obstructive apnea-hypopnea index (OAHI) as follows: mild = 1.5-4.9 events/h; moderate = 5-9.9 events/h; severe ≥ 10 events/h.

RESULTS

Seventy-five children with DS met inclusion criteria. The cohort included 41 males and 34 females with mean age of 5.1 years (± 3.6 years), range of 0.51-16.60 years. Preoperative OSA severity was as follows, mild = 8/75; moderate = 16/75; severe = 51/75. Cure rates varied depending on definition: 12% for OAHI < 1 event/h and 21% for OAHI < 2 events/h. 48% had residual OAHI < 5 events/h. On postoperative PSG 16/75 saw resolution (OAHI < 2) in OSA; mild = 21/75; moderate = 20/75; severe = 18/75. 48% moderate/severe patients saw conversion to mild or cure. Overall, tonsillectomy resulted in significant improvements in multiple respiratory parameters, including OAHI (OAHI; 21.3 ± 19.7 to 8.0 ± 8.1, P < .001), percent sleep time with oxygen saturations < 90% (19.0 ± 25.0 to 6.1 ± 10.1, P < .001), and percent sleep time with end-tidal carbon dioxide above 50 mmHg (7.7 ± 18.0 to 1.8 ± 6.6, P = .001). Average asleep oxygen saturation was associated with postoperative OSA severity.

CONCLUSIONS

Children with DS and OSA who undergo tonsillectomy experience improvements in both respiratory event frequency and gas exchange but approximately half still have moderate to severe residual OSA.

Longitudinal Cardiovascular Outcomes of Sleep Disordered Breathing in Children: A Meta-Analysis and Systematic Review

Objectives

The presence of sleep disordered breathing (SDB) is known to impact long-term cardiovascular morbidity in adults; however, the long-term effects in children are poorly understood. We aimed to systematically review and synthesize studies published to date on the long-term effects of SDB in children.

Study Design

Meta-analysis and systematic review using PubMed, CINAHL, Embase, and Scopus (all indexed years).

Methods

We searched for English-language articles containing original human data from prospective studies, with ≥7 participants, in children ≤18 years of age. Data regarding study design, demographics, clinical characteristics, outcomes, level of evidence, and risk of bias were obtained. Articles were independently reviewed by three investigators. Retrospective and cross-sectional studies were excluded.

Results

Of 1701 identified abstracts, 25 articles (combined n = 1418) were ultimately included. All studies reported longitudinal outcomes following treatment of SDB, 21 studies exclusively reporting outcomes after adenotonsillectomy. Therefore, studies were combined to objectively assess the effect of SDB treatment on cardiovascular outcomes. Although all cardiovascular parameters were within the normal range at baseline, at follow-up there was a significant decrease in mean pulmonary artery pressure, right ventricular end diastolic diameter, heart rate, mitral Em/Am ratio, and C-reactive protein. There was no significant change in interventricular septum thickness, left ventricular parameters (shortening fraction, systolic and end diastolic diameters, ejection fraction, posterior wall thickness, isovolumetric relaxation time), left atrial diameter, and aortic and pulmonary valve peak velocities.

Conclusions

Studies assessing the long-term cardiovascular effects of SDB in children are limited. The available literature indicates effects on autonomic function, right, and left heart function following treatment for SDB. However, well-designed, large-scale, prospective cohort studies (using standardized outcomes) are needed to better understand the relationship of cardiovascular morbidity in the context of pediatric SDB.

At-home pulse oximetry in children undergoing adenotonsillectomy for obstructive sleep apnea

Nocturnal pulse oximetry has a high positive predictive value for polysomnographically diagnosed obstructive sleep apnoea (OSA) in children. When significant adenotonsillar hypertrophy is diagnosed, adenotonsillectomy (T&A) represents a common treatment for OSA in children. We investigated the role of pulse oximetry in predicting those patients, referred for suspected OSA, who subsequently needed T&A. At-home nocturnal pulse oximetry was performed on 380 children (65.7% males), median age 4.1(IRQ 3.0-5.6) years, referred for suspected OSA, and data were retrospectively analysed. For each recording McGill Oximetry Score (MOS) was categorized. Mean pulse rate (PR) z-score and pulse rate variability (PRV)-corrected (PRSD/meanPR) were significantly higher in children with abnormal MOS. Both parameters were significantly higher in subjects who underwent T&A compared with those not surgically treated. Both DI₄ and PRV corrected showed a negative correlation with the elapsed time between pulse oximetry recordings and T&A. The logistic regression model showed a strong effect of an abnormal MOS as a predicting factor for T&A (adjusted odds ratio 19.7).

CONCLUSIONS

In our study, children with OSA who subsequently needed T&A showed higher PRV compared to those without surgical indication. Children with abnormal MOS were nearly 20 times more likely to undergo T&A. What is Known: • Nocturnal pulse oximetry has a high positive predictive value for polysomnographically diagnosed obstructive sleep apnoea in children. • When significant adenotonsillar hypertrophy is diagnosed, adenotonsillectomy represents a common treatment for OSA in children. What is New: • An abnormal pulse oximetry highly predict the indication for adenotonsillectomy. • We suggest the use of at-home pulse oximetry as method to predict prescription of adenotonsillectomy, and this may be useful in contexts where polysomnography is not readily available.

When and why to treat the child who snores?

Obstructive sleep-disordered breathing (SDB) can result in cardiovascular and neurocognitive morbidity as well as adversely affect behavior, growth, quality of life, and nocturnal continence. This article summarizes the latest evidence regarding the morbidity related to obstructive SDB, commenting on the impact of severity of obstruction, that is, the difference in effects seen of moderate to severe obstructive sleep apnea syndrome (OSAS) compared to those of mild OSAS or primary snoring. The impact of therapy is discussed, focusing on which children are likely to benefit from treatment interventions; namely those with moderate or severe OSAS irrespective of the presence of morbidity, children with mild OSAS with associated morbidity or predictors of SDB persistence such as obesity, and children with complex conditions accompanied by upper airway obstruction like craniosynostosis and Prader-Willi syndrome. The co-existing conditions which may improve when treatment for obstructive SDB is offered are reviewed, while the clinical parameters associated with spontaneous improvement or resolution of obstructive SDB are discussed. The intention being to enable clinicians to make informed decisions on who should be treated, when and why. Pediatr Pulmonol. 2017;52:399-412. © 2016 Wiley Periodicals, Inc.

Sleep disordered breathing and autonomic function in overweight and obese children and adolescents

Obstructive sleep apnoea (OSA), common in children with obesity, is associated with cardiovascular morbidity. Autonomic dysfunction has been suggested to be a key player in the development of these complications. We investigated the relationship between obesity, OSA and sympathetic activity in children.

191 children with obesity were included and distributed into two groups: 131 controls and 60 with OSA. Beat-to-beat RR interval data were extracted from polysomnography for heart rate variability analysis. Urinary free cortisol levels were determined.

Urinary free cortisol did not differ between groups and was not associated with OSA, independent of the level of obesity. Differences in heart rate variability measures were found: mean RR interval decreased with OSA, while low/high-frequency band ratio and mean heart rate increased with OSA. Heart rate variability measures correlated with OSA, independent of obesity parameters and age: oxygen desaturation index correlated with mean heart rate (r=0.19, p=0.009) and mean RR interval (r= −0.18, p=0.02), while high-frequency bands and low/high-frequency band ratio correlated with arterial oxygen saturation measured by pulse oximetry (S_pO2) (r= −0.20, p=0.008 and r= −0.16, p=0.04) and S_pO2 nadir (r=0.23, p=0.003 and r= −0.19, p=0.02).

These results suggest that sympathetic heart activity is increased in children with obesity and OSA. Measures of hypoxia were related to increased sympathetic tone, suggesting that intermittent hypoxia is involved in autonomic dysfunction.

Sympathetic heart activity is increased in children with obstructive sleep apnoea and obesityhttp://ow.ly/iSVc305AZRv

The effect of adenotonsillectomy for childhood sleep apnoea on cardiorespiratory control

The efficacy of adenotonsillectomy for relieving obstructive sleep apnoea symptoms in children has been firmly established, but its precise effects on cardiorespiratory control are poorly understood.

In 375 children enrolled in the Childhood Adenotonsillectomy Trial, randomised to undergo either adenotonsillectomy (n=194) or a strategy of watching waiting (n=181), respiratory rate, respiratory sinus arrhythmia and heart rate were analysed during quiet, non-apnoeic and non-hypopnoeic breathing throughout sleep at baseline and at 7 months using overnight polysomnography.

Children who underwent early adenotonsillectomy demonstrated an increase in respiratory rate post-surgery while the watchful waiting group showed no change. Heart rate and respiratory sinus arrhythmia were comparable between both arms. On assessing cardiorespiratory variables with regard to normalisation of clinical polysomnography findings during follow-up, heart rate was reduced in children who had resolution of obstructive sleep apnoea syndrome, while no differences in their respiratory rate or respiratory sinus arrhythmia were observed.

Adenotonsillectomy for obstructive sleep apnoea increases baseline respiratory rate during sleep. Normalisation of apnoea–hypopnoea index, spontaneously or via surgery, lowers heart rate. Considering the small average effect size, the clinical significance is uncertain.

Adenotonsillectomy for childhood obstructive sleep apnoea increases respiratory rate during sleephttp://ow.ly/Dptd300w9Pp

Neutrophil-Lymphocyte Ratio in Patients with Adenoidectomy

INTRODUCTION

Obstructive Sleep Apnea syndrome (OSA) is the most serious consequence of adenoid hypertrophy (AH) and it is one of the most common reasons of nocturnal hypoxia in children. There is some information about the relationship between childhood OSA and atherosclerosis or cardiac diseases. In this study, we evaluated the relationship between, neutrophil-lymphocyte ratio (NLR) and AH which is the most frequent cause leading OSA in children.

AIM

Thus we aimed to contribute about subject of preoperative and postoperative NLR values in patients undergoing adenoidectomy that there is limited information.

MATERIALS AND METHODS

The study group comprised 76 children undergoing adenoidectomy. A preoperative and 3(rd)-month postoperative complete blood cell count was performed to calculate the NLR values in all patients. The NLR values were calculated as the ratio of neutrophils to lymphocytes in peripheral blood. Data analysis was performed using SPSS 15.

RESULTS

The mean NLR (min - max) was 1.0 (0.16-3.57) preoperatively and 1.06 (0.35-4.95) 3 months postoperatively (p = 0.052> 0.05). Haemoglobin 12.9 ± 0.95 (preop) 12.94 ± 0.91 (postop) (p= 0.522), WBC (min-max) 7.75 (3.90-14.99) 7.8 (4-15.64) (p= 0.297 <0.005), platelet 344.5 ± 98.7 328.4 ± 68.9 (p<0,005).

CONCLUSION

There is limited information in the English literature. This study has investigated the association between the NLR and adenoidectomy. The results of the present study demonstrate that the NLR is not a statistically significant inflammatory factor. So, NLR values do not appear related to stage of upper airway obstruction.

Polysomnographic findings after adenotonsillectomy for obstructive sleep apnoea in obese and non-obese children: a systematic review and meta-analysis

BACKGROUND

Use of polysomnography (PSG) is the gold standard of diagnosis and measurement of treatment effectiveness for paediatric obstructive sleep apnoea (OSA). Although adenotonsillectomy (T&A) is effective in diminishing the apnoea-hypopnoea index (AHI), a meta-analysis of postoperative changes for all other PSG parameters and outcome comparisons between obese and non-obese children following T&A have never been conducted.

OBJECTIVE OF REVIEW

To comprehensively review polysomnographic findings after surgery for obese and non-obese children with OSA.

SEARCH STRATEGY

Study protocol was registered on PROSPERO (CRD42013004737). Two authors independently searched databases including PubMed, MEDLINE, EMBASE and Cochrane Review from January 1997 to July 2014. The keywords used included the following: sleep apnea, OSA, sleep apnea syndromes, tonsillectomy, adenoidectomy, infant, child, adolescent, and Humans.

EVALUATION METHOD

A comprehensive systematic review and meta-analysis for literature for OSA children treated by T&A with polysomnography data. Random-effects model was applied to determine postoperative sleep parameter changes and the surgical success rate between obese and non-obese groups. The quality of studies was assessed using the Newcastle-Ottawa Scale.

RESULTS

In total, 51 studies with 3413 subjects were enrolled. After surgery, sleep architecture was altered by a significant decrease in sleep stage 1, and an increase in slow-wave sleep and the rapid eye movement stage, and enhanced sleep efficiency. The mean difference between pre- and postoperative was a significant reduction of 12.4 event/h in AHI, along with a reduction of obstructive index, hypopnoea index, central index and arousal index. Mean and minimum oxygen saturation increased significantly after surgery. The overall success rate was 51% for postoperative AHI <1 (obese versus non-obese versus combined, 34% versus 49% versus 56%), and 81% for AHI <5 (obese versus non-obese versus combined, 61% versus 87% versus 84%). Meta-regression analyses demonstrate that postoperative AHI was positively correlated with AHI and body mass index z score before surgery.

CONCLUSIONS

Meta-analysis of current literature shows T&A offers prominent improvement in a variety of sleep parameters. Improvements in non-obese children exceeded those for obese children. Postoperative residual OSA remained in roughly half of the children, especially those with severe disease and obesity, making additional treatment strategies and/or long-term follow-up highly desirable.

Blood parameters as indicators of upper airway obstruction in children with adenoid or adenotonsillar hypertrophy

Adenotonsillar hypertrophy (ATH) is the most common cause of obstructive sleep apnea in children. This study aimed to evaluate the blood parameters of children with ATH who underwent surgery.

METHODS

The study included a review of the medical records of 130 children who underwent adenoidectomy or adenotonsillectomy with a diagnosis of adenoid hypertrophy and/or chronic tonsillitis. Patients were classified into 3 groups: group 1 (n=69) underwent adenoidectomy, group 2 (n=61) underwent adenotonsillectomy, and group 3 consisted of 82 healthy children. White blood cell count, platelet count, hemoglobin levels, mean platelet volume, and platelet distribution width values were the primary outcome measures.

RESULTS

Mean platelet volume, platelet distribution width and hemoglobin values decreased in the groups that underwent surgery. Whereas the decrease in group 1 was insignificant, it was significant in group 2. White blood cell count values increased in both group 1 (adenoidectomy) and group 2 (adenotonsillectomy), but the increase in group 2 was significant. No significant difference in platelet count was detected before versus after the operation.

CONCLUSIONS

Upper airway obstruction caused by ATH remarkably changes the blood parameters related to chronic hypoxia. Significant improvement can be achieved after adenotonsillectomy rather than adenoidectomy alone.

The Effect of Adenotonsillectomy for Childhood Sleep Apnea on Cardiometabolic Measures

STUDY OBJECTIVES

Obstructive sleep apnea syndrome (OSAS) has been associated with cardiometabolic disease in adults. In children, this association is unclear. We evaluated the effect of early adenotonsillectomy (eAT) for treatment of OSAS on blood pressure, heart rate, lipids, glucose, insulin, and C-reactive protein. We also analyzed whether these parameters at baseline and changes at follow-up correlated with polysomnographic indices.

DESIGN

Data collected at baseline and 7-mo follow-up were analyzed from a randomized controlled trial, the Childhood Adenotonsillectomy Trial (CHAT).

SETTING

Clinical referral setting from multiple centers.

PARTICIPANTS

There were 464 children, ages 5 to 9.9 y with OSAS without severe hypoxemia.

INTERVENTIONS

Randomization to eAT or Watchful Waiting with Supportive Care (WWSC).

MEASUREMENTS AND RESULTS

There was no significant change of cardiometabolic parameters over the 7-mo interval in the eAT group compared to WWSC group. However, overnight heart rate was incrementally higher in association with baseline OSAS severity (average heart rate increase of 3 beats per minute [bpm] for apnea-hypopnea index [AHI] of 2 versus 10; [standard error = 0.60]). Each 5-unit improvement in AHI and 5 mmHg improvement in peak end-tidal CO2 were estimated to reduce heart rate by 1 and 1.5 bpm, respectively. An increase in N3 sleep also was associated with small reductions in systolic blood pressure percentile.

CONCLUSIONS

There is little variation in standard cardiometabolic parameters in children with obstructive sleep apnea syndrome (OSAS) but without severe hypoxemia at baseline or after intervention. Of all measures, overnight heart rate emerged as the most sensitive parameter of pediatric OSAS severity.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov (#NCT00560859).

Pupillometric findings in children with obstructive sleep apnea

BACKGROUND

Obstructive sleep apnea (OSA) leads to intermittent hypoxia, activation of the sympathetic nervous system, and eventually cardiovascular morbidity. Alterations in autonomic nervous system (ANS) tone and reflexes are likely to play major roles in OSA-associated morbidities, and have been identified in a subset of children with OSA.

OBJECTIVES

To evaluate whether pupillometry, a noninvasive and rapid bedside test for the assessment of autonomic nervous system dysfunction (ANS), would detect abnormal ANS function in children with OSA.

METHODS

Children ages 2-12 years underwent polysomnography (PSG), and were divided based on PSG findings into two groups; Habitual Snorers (HS; AHI < 1 h/TST, n = 17) and OSA (AHI > 1 h/TST, n = 49), the latter then sub-divided into AHI severity categories (>1 but <5, >5 but <10, and >10 h/TST). Pupillometric measurements were performed during the clinic visit in a dark room using an automated pupillometer device.

RESULTS

A total of 66 subjects with a mean age of 7.3 ± 2.6 years were recruited. There were no statistically significant differences between any of the groups, even when comparing severe OSA (n = 15) and HS in any of the measures related to pupillary reflexes. However, mild, yet significant increases in systolic blood pressure and morning plasma norepinephrine levels were detected in the severe OSA group.

CONCLUSION

Although ANS perturbations are clearly present in a proportion of children with OSA, particularly those with severe disease, pupillary responses do not appear to provide a sensitive method for the detection of ANS dysfunction in OSA children.

A systematic review and meta-analysis of cohort studies of echocardiographic findings in OSA children after adenotonsilectomy

CONTEXT

There is evidence that OSA in children can be associated with acute and chronic effects on the cardiovascular system due to repetitive episodes of apnea and hypoxemia.

OBJECTIVE

To assess whether there is an association between OSA and echocardiographic findings in children and whether that association persists after adenotonsillectomy.

DATA SOURCES

A literature search was conducted based on PUBMED, EMBASE and LILACS.

STUDY SELECTION

Children with OSA and children who did not have OSA, who were aged ≤12 years.

DATA EXTRACTION

Two reviewers extracted data independently; the risk of bias was assessed by examining the selected sample, the recruitment method, completeness of follow up, and blinding.

RESULTS

Seven studies met all the inclusion criteria and methodological requirements. There was a significant difference with elevated mean pulmonary arterial pressure levels in OSA participants compared to those without OSA at preoperative assessment [mean difference (MD) 8.67; confidential interval (CI) 95% 6.09, 11.25]. OSA participants showed a statistically significant increased interventricular septum (IVS) thickness (mm) [MD 0.60; CI 95% 0.09, 1.11]; and right ventricular (RV) dimension (cm/m) [MD 0.19; CI 95% 0.10, 0.28]. There was also a significant increase in right ventricular (RV) dimension (cm/m) [MD 0.10; CI 95% 0.05, 0.14] in OSA children.

CONCLUSION

There is moderate quality evidence regarding possible association between OSA and right heart repercussions. More prognosis studies are needed, to allow the combination of results in a meta-analysis.

Poincaré plot width, morning urine norepinephrine levels, and autonomic imbalance in children with obstructive sleep apnea

BACKGROUND

Obstructive sleep apnea (OSA) in childhood is accompanied by sympathetic overflow unopposed by the parasympathetic tone. Complex methods like power spectral analysis of heart rate variability have been applied to study this imbalance. In this report, width of Poincaré scattergram of the R-R interval (parasympathetic tone) and morning urine norepinephrine concentration (sympathetic activity) were used to assess autonomic imbalance.

METHODS

Poincaré plot was obtained from the electrocardiographic channel of nocturnal polysomnography and its width was measured, and norepinephrine-to-creatinine concentration ratio was calculated in morning urine specimen.

RESULTS

Twenty children with obstructive sleep apnea and moderate-to-severe nocturnal hypoxemia (oxygen saturation of hemoglobin [SpO(2)] nadir <90%), 24 subjects with mild hypoxemia (SpO(2) nadir ≥90%), and 11 control subjects were recruited. Children with obstructive sleep apnea and moderate-to-severe hypoxemia had significantly narrower Poincaré plot width (318.7 ± 139.3 ms) and higher ln-transformed urine norepinephrine-to-creatinine ratio (4.5 ± 0.6) than control subjects (484.2 ± 104.4 ms and 3.8 ± 0.4, respectively; P < 0.05). Ln-transformed urine norepinephrine levels were inversely related to Poincaré plot width (P = 0.02).

CONCLUSIONS

Subjects with obstructive sleep apnea and moderate-to-severe nocturnal hypoxemia have enhanced sympathetic activity and reduced parasympathetic drive. Poincaré plot width and urine norepinephrine levels are simple measures of autonomic imbalance in pediatric obstructive sleep apnea.

Prevalence of pediatric periodic leg movements of sleep after initiation of PAP therapy

INTRODUCTION

Positive-airway-pressure (PAP) is a treatment for obstructive-sleep-apnea (OSA). In adults, initiation of PAP-therapy may unmask periodic-limb movements-of-sleep (PLMS). We present a series of children in whom PLMS was aggravated or induced following initiation of PAP therapy.

METHODS

Retrospective analysis was performed on children who had PAP-studies performed over a 3-year period. Children with OSA without significant PLMS on baseline studies and who then showed a periodic-limb-movement-index (PLMI) (>5/hr) during titration with PAP-therapy were identified. Charts were reviewed for demographics, OSA severity based on apnea hypopnea index (AHI), PLMI, PLM-arousal-index (PLMAI) and pressures titrated.

RESULTS

Two hundred fourteen PAP-titration studies (151 on continuous positive airway pressure [CPAP] and 63 on bilevel positive airway pressure [BiPAP]) were done. Eleven (10 on CPAP, 1 on BiPAP) met study criteria. Eight patients were boys. The median age was 12 years (range 6 months-18 years). On baseline studies, median AHI was 5/hr (range 1.5-32/hr), median PLMI was 1/hr (range 0-4/hr) and median PLMAI 0.3/Hr (range 0-2/hr). On titration studies, pressures ranged from 4 to 14 cm of water, median AHI was 0.5/hr (range 0-1), median PLMI was 12/hr (range 5-55/hr) and median PLMAI 9/hr (range 0-25). PLMS were seen predominantly during N1, N2 sleep and on PAP of >7 cm of water. One patient had resolution of PLMS at 1-year follow-up.

CONCLUSION

PLMS were seen in 5.1% of children after initiation of PAP. OSA may mask PLMS, which appears as breathing improves. Alternatively, PAP may unmask or induce PLMS. PLMS may potentially be a cause of treatment failure in children on recent-onset PAP therapy.

Values of mean platelet volume in patients with chronic tonsillitis and adenoid hypertrophy

Objectives: Chronic tonsillitis (CT)-adenoid hypertrophy (AH) is the most common cause of obstructive sleep apnea (OSA), which is one of the most common reasons of nocturnal hypoxia in children. However, there is limited information about the relationship between childhood OSA and atherosclerosis or cardiac diseases. In the present study, we evaluated the relationship between mean platelet volume (MPV) and CT-AH which is the most frequent cause leading OSA in children.

Methodology: The medical records of 200 children, who underwent adenoidectomy or adenotonsillectomy with a diagnosis of adenoid hypertrophy and/or chronic tonsillitis between October, 2010 and June, 2012, and 240 healthy controls were evaluated. Subjects were classified into 3 groups. Group I consisted of patients who underwent adenoidectomy, whereas Group II consisted of patients who had adenotonsillectomy. Healthy children were employed as control group. White blood cell count (WBC), platelet count (PLT), hemoglobin (Hb) levels and mean platelet volume (MPV) values were recorded individually.

Results: MPV values were 6.6±0.8, 6.6±0.7 and 7.3±0.9 in Group I, Group II and control group, respectively. It was found that MPV values in groups I and II were significantly lower than control group. There was no significant difference between group I and II.

Conclusion: Obstructive sleep apnea (OSA) caused by CT-AH is associated with low MPV values in childhood.

Circulating adropin concentrations in pediatric obstructive sleep apnea: potential relevance to endothelial function

OBJECTIVE

To test the hypothesis that concentrations of adropin, a recently discovered peptide that displays important metabolic and cardiovascular functions, are lower in obstructive sleep apnea (OSA), especially when associated with endothelial dysfunction.

STUDY DESIGN

Age-, sex-, and ethnicity-matched children (mean age, 7.2 ± 1.4 years) were included into 1 of 3 groups based on the presence of OSA in an overnight sleep study, and on the time to postocclusive maximal reperfusion (Tmax >45 seconds) with a modified hyperemic test. Plasma adropin concentrations were assayed using a commercial enzyme-linked immunosorbent assay kit.

RESULTS

Among controls, the mean morning adropin concentration was 7.4 ng/mL (95% CI, 5.2-16.3 ng/mL). Children with OSA and abnormal endothelial function (EF) (OSA(+)/EF(+) group) had significantly lower adropin concentrations (2.7 ± 1.1 ng/mL; n = 35) compared with matched controls (7.6 ± 1.4 ng/mL; n = 35; P < .001) and children with OSA and normal EF (OSA(+)/EF(-) group; 5.8 ± 1.5 ng/mL; n = 47; P < .001). A plasma adropin concentration <4.2 ng/mL reliably predicted EF status, but individual adropin concentrations were not significantly correlated with age, body mass index z-score, obstructive apnea-hypopnea index, or nadir oxygen saturation. Mean adropin concentration measured after adenotonsillectomy in a subset of children with OSA (n = 22) showed an increase in the OSA(+)/EF(+) group (from 2.5 ± 1.4 to 6.4 ± 1.9 ng/mL; n = 14; P < .01), but essentially no change in the OSA(+)EF(-) group (from 5.7 ± 1.3 to 6.4 ± 1.1 ng/mL; n = 8; P > .05).

CONCLUSION

Plasma adropin concentrations are reduced in pediatric OSA when endothelial dysfunction is present, and return to within normal values after adenotonsillectomy. Assessment of circulating adropin concentrations may provide a reliable indicator of vascular injury in the context of OSA in children.

Nocturnal autonomic function in preschool children with sleep-disordered breathing

BACKGROUND

Obstructive sleep apnea (OSA) is associated with autonomic dysfunction in adults and school-aged children; however, this association has not been investigated in preschool children. We aimed to analyze heart rate variability (HRV) and catecholamine levels in preschool children with OSA.

METHODS

One hundred and forty-two snoring children aged 3-5years and 38 nonsnoring control group children underwent overnight polysomnography (PSG). Nocturnal urinary catecholamines were measured in 120 children. Children were grouped according to their obstructive apnea-hypopnea index (OAHI) (control [no snoring], OAHI⩽1event/h; primary snoring, OAHI⩽1event/h; mild OSA OAHI>1⩽5events/h; moderate to severe [MS] OSA, OAHI>5events/h). The HRV parameters for each child were averaged during rapid eye movement (REM) and non-REM (NREM) sleep.

RESULTS

During stable sleep, low-frequency (LF) HRV was similar between groups. High-frequency (HF) HRV was higher in the MS OSA group compared with the control group during all sleep stages (NREM sleep stages 1 and 2 [NREM1/2], 4234±523ms(2) vs 2604±457ms(2); NREM sleep stages 3 and 4 [NREM3/4], 4152±741ms(2) vs 3035±647ms(2); REM, 1836±255ms(2) vs 1456±292ms(2); P<.01 for all). The LF/HF ratio was lower in the MS OSA group compared with the control group (NREM1/2, 0.4±0.06 vs 0.7±0.05; NREM3/4, 0.3±0.06 vs 0.4±0.05; REM, 0.8±0.1 vs 1.3±0.1; P<.01 for all). Catecholamine levels were not different between groups.

CONCLUSIONS

In preschool children, OSA is associated with altered HRV, largely due to the HF fluctuations in heart rate (HR) which occur during respiratory events and are still evident during stable sleep. The preschool age may represent a window of opportunity for treatment of OSA before the onset of the severe autonomic dysfunction associated with OSA in adults and older children.

Characterization of the acute pulse transit time response to obstructive apneas and hypopneas in preschool children with sleep-disordered breathing

BACKGROUND

Surges in heart rate (HR) and blood pressure (BP) at apnea termination contribute to the hypertension seen in obstructive sleep apnea (OSA). Because childhood OSA prevalence peaks in the preschool years, we aimed to characterize the cardiovascular response to obstructive events in preschool-aged children.

METHODS

Clinically referred children aged 3-5 years were grouped by obstructive apnea-hypopnea index (OAHI) into the following: primary snoring (PS) (OAHI≤1 event/h [n=21]), mild OSA (OAHI>1-≤5 [n=32]), and moderate to severe (MS) OSA (OAHI>5 [n=28]). Beat-to-beat pulse transit time (PTT), an inverse continuous indicator of BP changes, and HR were averaged during the two halves (early and late) and during the peak after (post) each obstructive event and were expressed as percentage change from late- to post-event.

RESULTS

We analyzed 422 events consisting of 55 apneas and 367 hypopneas. A significant post-event increase in HR and fall in PTT occurred in all severity groups (P<.05 for all). A greater response was associated with OSA, nonrapid eye movement sleep (NREM), cortical arousal, hypopneas, and oxygen desaturation (P<.05 for all).

CONCLUSIONS

Obstructive events elicit acute cardiovascular changes in preschool children. Such circulatory perturbations have been implicated in the development of hypertension, and our findings complement previous studies to suggest a cumulative impact of snoring on the cardiovascular system from childhood into adulthood.