24-Hour Ambulatory Blood Pressure Variability in Children with Obstructive Sleep Apnea

Obstructive sleep apnea and hypertension; critical overview

Obstructive sleep apnea (OSA) and hypertension are two important modifiable risk factors for cardiovascular disease and mortality. Numerous studies have highlighted the interplay between these two conditions. We provide a critical review of the current literature on the role of the OSA as a risk factor for hypertension and its effect on blood pressure (BP). We discuss several key topics: the effect of OSA on nocturnal BP, BP response to continuous positive airway pressure (CPAP) treatment, CPAP effect on BP in refractory hypertension, the role of OSA in BP variability (BPV), and maladaptive cardiac remodeling mediated by OSA's effect on BP. Finally, we discuss the unique aspects of ethnicity and social determinants of health on OSA with a focus on Asian populations and the disparity in BP control and cardiovascular outcomes.

Circadian blood pressure dysregulation in children with obstructive sleep apnea

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) adversely affects normal blood pressure (BP) and may disrupt circadian BP patterns. We sought to examine 24-hour circadian BP rhythms in children with OSA and healthy controls.

METHODS

Children 5-14 years with OSA and healthy controls underwent 24-hour BP monitoring and actigraphy to quantify sleep. Shape invariant statistical models compared circadian BP patterns (e.g. times of BP peaks, time arrived at peak BP velocity [TAPV]) in the OSA and control groups.

RESULTS

The analytic sample included 219 children (mild OSA: n = 52; moderate-to-severe OSA (MS-OSA): n = 50; controls: n = 117). In the morning, the MS-OSA group had earlier TAPV for DBP than controls (51 minutes, p < 0.001). TAPV in the evening was earlier for the MS-OSA group than controls (SBP: 95 minutes, p < 0.001; DBP: 28 minutes, p = 0.028). At mid-day, SBP and DBP velocity nadirs were earlier for the MS-OSA group than controls (SBP: 57 minutes, p < 0.001; DBP: 38 minutes, p < 0.01). The MS-OSA group reached most BP values significantly earlier than controls; the largest differences were 118 minutes (SBP) and 43 minutes (DBP) (p < 0.001). SBP and DBP were elevated in the MS-OSA group (hours 18-21 and 7--12, respectively, p < 0.01) compared to controls. The MS-OSA group was prone to "non-dipping" compared to controls (SBP: odds ratio [OR] = 2.16, 95% CI: 1.09, 4.29; DBP: OR = 3.45, 95% CI: 1.21, 10.23).

CONCLUSIONS

Children with MS-OSA had changes in circadian BP patterns, namely earlier TAPV and BP peaks and nadirs than controls. Circadian disturbances in BP rhythms may be key to mapping the natural history of BP dysregulation in children with OSA.

Ambulatory Blood Pressure Variability after Adenotonsillectomy in Childhood Sleep Apnea

OBJECTIVE

To investigate the influence of adenotonsillectomy (T&A) on ambulatory blood pressure (BP) variability in children with obstructive sleep apnea (OSA).

STUDY DESIGN

Prospective, interventional study.

METHODS

Children with OSA symptoms were recruited from a tertiary center. After OSA diagnosis was confirmed (ie, apnea-hypopnea index [AHI] > 1), these children underwent T&A for treatment. We performed polysomnography and 24-hour recordings of ambulatory BP before and 3 to 6 months postoperatively. Ambulatory BP variability was presented as the standard deviation of mean blood pressure in the 24-hour monitoring of ambulatory BP. Differences in BP variability among different subgroups were tested using a multivariable linear mixed model.

RESULTS

A total of 190 children were enrolled (mean age: 7.8 ± 3.3 years; 73% were boys; 34% were obese). The AHI significantly decreased from 12.3 ± 17.0 to 2.7 ± 5.5 events/hr after T&A. Overall, daytime, and nighttime ambulatory BP did not significantly change postoperatively, and overall, daytime, and nighttime ambulatory BP variability did not differ significantly preoperatively and postoperatively. In the subgroup analysis, children aged <6 years demonstrated a significantly greater decrease in ambulatory BP variability postoperatively than those aged >6 years (nighttime diastolic BP variability: 9.9 to 7.7 vs. 8.9 to 9.4). Children with hypertension also showed a significantly greater decrease in ambulatory BP variability than those without hypertension.

CONCLUSIONS

We concluded that overall ambulatory BP variability does not significantly change after T&A in children with OSA. Moreover, young-aged and hypertensive children demonstrate a significant decrease in BP variability after T&A.

LEVEL OF EVIDENCE

4 Laryngoscope, 132:2491-2497, 2022.

Prevalence of sleep disorders in children with chronic kidney disease: a meta-analysis

BACKGROUND

The reported prevalence of sleep disorders in children with chronic kidney disease (CKD) varies greatly. A quantitative meta-analysis to estimate the prevalence of sleep disorders among pediatric CKD patients may provide further information.

OBJECTIVES

The objective of this study is to estimate the prevalence of sleep disorders in children with CKD. The study protocol was registered on PROSPERO (registration number CRD42021268378).

DATA SOURCES

Two authors independently searched the PubMed, MEDLINE, EMBASE, and Cochrane review databases up to June 2021.

STUDY ELIGIBILITY CRITERIA

Eligible studies include data of prevalence of sleep disorders in children with CKD.

STUDY APPRAISAL AND SYNTHESIS METHODS

The prevalence of restless legs syndrome, sleep-disordered breathing, pediatric obstructive sleep apnea (i.e., apnea-hypopnea index &gt; 1 event/h in polysomnography), excessive daytime sleepiness, and insomnia/insufficient sleep was estimated using a random-effects model. Subgroup analyses were conducted to compare the prevalence of sleep disorders between children on dialysis and not on dialysis. This meta-analysis included 12 studies with 595 children (mean age: 12.9 years; gender ratio: 55.6% boys; mean sample size: 49.6 patients).

RESULTS

The prevalence of restless legs syndrome in children with CKD was 21% (95% confidence interval [CI], 14-30%). The prevalence of sleep-disordered breathing, pediatric obstructive sleep apnea, excessive daytime sleepiness, and insomnia/insufficient sleep was 22% (95% CI, 12-36%), 34% (95% CI, 19-53%), 27% (95% CI, 17-41%), and 14% (95% CI, 7-27%), respectively. Subgroup analysis revealed the pooled prevalence of excessive daytime sleepiness was significantly higher in children on dialysis than in children not on dialysis (43.3% vs. 11.2%; P = 0.018). Children on dialysis also had a high prevalence of other sleeping disorders, although the differences did not reach statistical significance. Children with CKD exhibited a 3.9-fold (95% CI, 1.37 to 10.93) increased risk of restless legs syndrome and a 9.6-fold (95% CI, 3.57 to 25.76) increased risk of excessive daytime sleepiness compared with controls.

LIMITATIONS

The selected papers are of small sample size, lack of a control group, and exhibit substantial heterogeneity.

CONCLUSIONS

Sleep disorders are common in children with CKD. Our results indicate that while the prevalence rates of various sleep disorders were higher in children on dialysis than in children not on dialysis, the prevalence of excessive daytime sleepiness was statistically significant in children on dialysis. A higher resolution version of the Graphical abstract is available as Supplementary information.

Recent advances in paediatric sleep disordered breathing

This article reviews the latest evidence pertaining to childhood sleep disordered breathing (SDB), which is associated with negative neurobehavioural, cardiovascular and growth outcomes. Polysomnography is the accepted gold standard for diagnosing SDB but is expensive and limited to specialist centres. Simpler tests such as cardiorespiratory polygraphy and pulse oximetry are probably sufficient for diagnosing obstructive sleep apnoea (OSA) in typically developing children, and new data-processing techniques may improve their accuracy. Adenotonsillectomy is the first-line treatment for OSA, with recent evidence showing that intracapsular tonsillectomy results in lower rates of adverse events than traditional techniques. Anti-inflammatory medication and positive airway pressure respiratory support are not always suitable or successful, although weight loss and hypoglossal nerve stimulation may help in select comorbid conditions.

Educational aims

To understand the clinical impact of childhood sleep disordered breathing (SDB).To understand that, while sleep laboratory polysomnography has been the gold standard for diagnosis of SDB, other diagnostic techniques exist with their own benefits and limitations.To recognise that adenotonsillectomy and positive pressure respiratory support are the mainstays of treating childhood SDB, but different approaches may be indicated in certain patient groups.

Office Blood Pressure Monitoring in Children with Obesity and Obstructive Sleep Apnea

OBJECTIVE

To investigate the relative contributions of obesity and obstructive sleep apnea (OSA) to unfavorable blood pressure in children.

STUDY DESIGN

Children aged 3-18 years with OSA-related symptoms were recruited. All children underwent office blood pressure (BP) monitoring and full-night polysomnography. Obesity was defined as a body mass index ≥95th percentile. OSA severity was divided into primary snoring (apnea-hypopnea index [AHI] <1), mild OSA (5> AHI ≥1), and moderate to severe OSA (AHI ≥5). Age- and sex-adjusted logistic regression analysis was performed to determine the associations among OSA, obesity, and elevated BP.

RESULTS

This cross-sectional study enrolled 1689 children (66% boys), with a mean age of 7.9 years. Compared with children with primary snoring, children with moderate to severe OSA had significantly higher systolic BP (108.1 mmHg vs 105.6 mmHg), diastolic BP (75.0 mmHg vs 70.4 mmHg), systolic BP percentile (75.0 vs 70.4), and diastolic BP percentile (74.0 vs 69.2). The rate of unfavorable BP (ie, elevated BP or hypertension level BP) also was significantly higher in children with more severe OSA. Children with obesity had higher BP and BP percentile. Logistic regression analysis revealed that children with obesity and moderate to severe OSA have a 3-fold greater risk of unfavorable BP compared with children without obesity and primary snoring.

CONCLUSIONS

We identified a 3-fold greater risk of unfavorable BP in children with obesity and moderate to severe OSA.

Age- and gender-related characteristics in pediatric obstructive sleep apnea

BACKGROUND

Age and gender disparities in polysomnographic findings in children are not well understood.

OBJECTIVE

This study determined age and gender-related characteristics in pediatric obstructive sleep apnea (OSA).

METHOD

Retrospectively, data were collected. We analyzed polysomnographic data in the following age groups: 3-6 years (n = 681), 6-9 years (n = 553), 9-12 years (n = 297), 12-15 years (n = 200), and 15-18 years (n = 111).

RESULTS

A total of 1842 children were included (mean age: 8.0 years; boys: 67%; obesity: 21%). The apnea-hypopnea index (AHI) gradually increased with age (3-6, 6-9, 9-12, 12-15, and 15-18 years groups: 6.2, 5.9, 6.5, 8.1, and 9.9 event/h, respectively; p trend = 0.002). In all age groups, boys had a higher AHI than girls (7.8 vs. 4.1 events/h, p < 0.001). Children with obesity had a higher AHI than those without (12.9 vs. 4.9 events/h, p < 0.001). The mean AHI in the boys increased with age (3-6 to 15-18 years groups: 7.0-13.6 events/h, respectively; p trend < 0.001), whereas the mean AHI in the girls was not significantly different between ages (p trend = 0.492). In moderation analyses, gender was a moderator in the association between obesity and AHI, and the association between age and AHI during 12-15 and 15-18 years of ages.

CONCLUSION

Male gender and obesity increase risk of OSA. Regarding age disparities, this study discovered a higher AHI in male adolescents than in young boys.

The 3% Oxygen Desaturation Index is an Independent Risk Factor for Hypertension Among Children with Obstructive Sleep Apnea

BACKGROUND

Obstructive sleep apnea (OSA) and obesity are both directional risk factors of hypertension. Chronic intermittent hypoxemia (IH) is a commonly observed pathophysiological mechanism involved in multiple comorbidities of OSA. However, their interactions are not well understood in children. This study aimed to investigate the associations of IH indexes (oxygen desaturation index 3% [ODI3], mean peripheral oxygen saturation [SpO₂], least SpO₂, and time with SpO₂ < 85%), apnea-hypopnea index, and weight status with hypertension in a sample of pediatric OSA patients.

METHODS

The medical records of 365 pediatric OSA patients were retrospectively reviewed in this cross-sectional study. Demographics, anthropometrics, standard in-laboratory polysomnography, and nocturnal blood pressure were collected. Multivariate logistic regression with forward selection was used to identify independent predictors of hypertension.

RESULTS

Multivariate logistic regression analysis showed that ODI3 (odds ratio [OR] = 1.02, 95% confidence interval [CI] = 1.01-1.03) and body mass index z-score (OR = 1.34, 95% CI = 1.12-1.60) were independent continuous predictors of pediatric hypertension, whilst severe OSA (OR = 2.62, 95% CI = 1.60-4.29) and overweight/obesity (OR = 2.63, 95% CI = 1.59-4.34) were independent categorical predictors. Traditional risk factors including male sex (OR = 2.33, 95% CI = 1.02-5.33), late childhood/adolescence (OR = 1.98, 95% CI = 1.01-3.88), and overweight/obesity (OR = 2.97, 95% CI = 1.56-5.67) combined with sleep hypoxemia (least SpO₂ ≤ 95%) (OR = 2.24, 95% CI = 1.16-4.04) predicted hypertension (R ² = 0.21) in the severe IH subgroup (n = 205), while the no/mild IH subgroup (n = 160) had an entirely different predictor, severe OSA (OR = 3.81, 95% CI = 1.49-9.74) (R ² = 0.07).

CONCLUSION

The close relationships among IH, overweight/obesity, and hypertension highlight the importance of reducing IH and body weight in children with OSA.

Overweight/Obese Status Synergistically Worsens Nocturnal Time-to-Time Blood Pressure in Children with Obstructive Sleep Apnea

OBJECTIVE

To investigate the influence of obstructive sleep apnea (OSA) severity and weight on blood pressure (BP) during nighttime sleep in children.

METHODS

Habitually snoring children who were 3-14 years old and from Beijing Children's Hospital between 1 January 2018 and 31 December 2020 were recruited. All participants completed polysomnography (PSG) and BP monitoring during different sleep stages using pulse transit time analysis. Subjects were divided into three groups based on the obstructive apnea-hypopnea index (OAHI), ie, primary snoring (PS), mild-to-moderate OSA, and severe OSA group.

RESULTS

Totally, 284 habitually snoring children were enrolled, including 85 with PS, 152 with mild-to-moderate OSA, and 47 with severe OSA. The differences of age and sex ratio among groups were not statistically significant (all P>0.05). For the normal weight group, compared with those in the PS group, children in the severe OSA group had higher BP, mainly in N2 and R stages, and children in the mild-to-moderate OSA group had lower BP in all sleep and wake stages (all P<0.01). For the overweight/obese group, compared with the PS group, children in the severe OSA group had higher BP in all sleep and wake stages, and children in the mild-to-moderate group had higher BP mainly in sleep stages (all P<0.01). Compared with normal weight children, those who were overweight/obese and had OSA had higher BP in all sleep and wake stages (all P<0.01). There was a synergistic effect of OSA and weight status on BP (P<0.01).

CONCLUSION

The influence of OSA on both systolic and diastolic pediatric BP differs between children with normal weight and overweight/obese status. Overweight/obese status synergistically worsens nocturnal blood pressure in children with OSA. Early diagnosis and risk stratification are more important in overweight/obese children with OSA to achieve timely initiation of treatment.

C-reactive protein in children with obstructive sleep apnea and effects of adenotonsillectomy

OBJECTIVE

C-reactive protein (CRP) is an important serum marker of inflammation associated with cardiovascular outcomes. This study aims to evaluate the association between CRP and childhood obstructive sleep apnea (OSA) and clarify the effects of adenotonsillectomy on serum CRP levels in children with OSA.

METHODS

Children with symptoms suggestive of OSA who underwent an overnight polysomnography were recruited from a tertiary medical center. Their serum CRP levels were measured. For children who underwent adenotonsillectomy for OSA treatment, polysomnography and serum high-sensitivity CRP (hs-CRP) level measurement were conducted after surgery.

RESULTS

This study included 326 children (mean age: 7.2 ± 3.0 years; boys: 67%). Children with apnea-hypopnea index (AHI) > 5 events/h had significantly higher hs-CRP levels than children with AHI of 1-5 events/h and AHI < 1 event/h [median (interquartile range): 0.08 (0.03-0.25) vs 0.03 (0.02-0.14) vs 0.04 (0.01-0.10), P < 0.001]. Log-transformed hs-CRP levels were positively associated with log AHI values (r = 0.2, P < 0.001). In multiple linear regression analysis, hs-CRP levels were independently associated with AHI; 101 children with OSA (ie, AHI > 1) underwent adenotonsillectomy. In children with OSA in the study cohort, a significant reduction of hs-CRP levels did not occur after surgery [from 0.07 (0.02-0.22) to 0.08 (0.03-0.17), P = 0.716]. In children with OSA having abnormal hs-CRP levels (ie, CRP > 1 mg/dL), hs-CRP levels significantly decreased after surgery [from 1.87 (1.11-2.78) to 0.20 (0.07-1.04), P = 0.043].

CONCLUSION

Children with OSA had increased hs-CRP levels. Children with OSA and abnormal hs-CRP levels exhibited significantly reduced hs-CRP levels following adenotonsillectomy.

Effect of adenotonsillectomy on blood pressure in children with obstructive sleep apnea: a meta-analysis

BACKGROUND

While adenotonsillectomy (T&A) is widely recognized as the first-line therapy for pediatric obstructive sleep apnea (OSA), effects of T&A on blood pressure (BP) remain unclear. This meta-analysis evaluates the associations between T&A and BP in children with OSA.

METHODS

The study protocol was registered on PROSPERO (CRD42020154425). Two authors independently searched the PubMed, Medline, EMBASE, and Cochrane databases. The keywords used were "sleep apnea syndromes," "adenotonsillectomy," and "child." A random-effects model was applied to determine office systolic BP (SBP), diastolic BP (DBP), and ambulatory BP changes.

RESULT

Twelve studies with 1193 children were analyzed (mean age: 7.6 y; 54% boys). The apnea-hypopnea index significantly reduced of 9.4 events/h (95% CI, -12.0 to -6.8) after T&A. Office SBP (-0.24 mmHg; 95% CI, -1.64 to 1.16) and DBP (-1.65 mmHg; 95% CI, -3.47 to 0.17) did not decrease significantly after surgery. No significant decreases were observed in 24-h ambulatory BP after T&A. Subgroup analysis showed a significant postoperative decrease in office SBP (-6.23 mmHg; 95% CI, -7.78 to -4.67) and DBP (-7.93 mmHg; 95% CI, -10.37 to -5.48) among children with hypertension but a slight increase in office SBP (2.50 mmHg; 95% CI, 1.14 to 3.86) and DBP (1.98 mmHg; 95% CI, -0.02 to 3.98) in those without (P for heterogeneity < 0.001).

CONCLUSION

This meta-analysis suggests the office and ambulatory BP changes after T&A in children with OSA are trivial. Moreover, children with hypertension experience a significantly greater decrease in office BP than children without hypertension.

Sleep Monitoring of Children With Nocturnal Enuresis: A Narrative Review

The purpose of this article is to provide a succinct summary of the sleep monitoring efforts that have been used in nocturnal enuresis (NE) and an overview of the knowledge that has accrued. This is not intended to be a comprehensive review, but rather is intended to highlight how polysomnography (PSG), a common sleep detection tool, has contributed to our understanding of NE, as arousal disorder is considered to be one of the important mechanisms. The authors have organized this report by analysis and display of different ingredients of PSG, starting with comparing the electroencephalogram (EEG) of controls and the enuretic children and then moving to evaluation of respiratory patterns of NE and comorbid disease obstructive sleep apnea (OSA). In addition, the authors' goal is to better understand the mechanism of NE by integrating various levels of sleep monitoring; those sleep-related clinical scale scores for NE are presented to date. Finally, we propose further research of NE to explore the microstructure alterations via PSG combined with EEG-fMRI or to use novel technology like portable device internet and deep learning strategy.