Validity analysis of respiratory events of polysomnography using a plethysmography chest and abdominal belt

Purpose

Respiratory inductive plethysmography (RIP) is recommended as an alternative respiratory sensor for the identification of each apnea and hypopnea event in polysomnography. Using this sensor, the cumulative RIP results from the chest and abdomen (RIP sum) and time-derived results of the RIP sum (RIP flow) are calculated to track respiratory flow. However, the effectiveness of this sensor and the calculated respiratory results is still unclear, and validation studies for the scoring of respiratory events in polysomnography are rare.

Methods

Two hundred subjects were selected according to the severity of obstructive sleep apnea. A sleep specialist re-evaluated the respiratory events based on RIP flow data in a single-blind study. Statistical analysis was conducted with paired respiratory events scored in each of the RIP flow and polysomnography datasets.

Results

All respiratory events scored from the RIP flow were strongly correlated with those identified with standard sensors of polysomnography, regardless of disease severity. Most of the respiratory parameters from RIP flow trended toward underestimation. The RIP flow obtained from the alternative RIP sensor was appropriate for the diagnosis of obstructive sleep apnea based on a receiver operating characteristic curve.

Conclusions

Scored respiratory events from RIP flow data effectively reflected the respiratory flow and statistically correlated with the results from standard polysomnography sensors. Therefore, analyzing RIP flow utilizing an RIP sensor is considered a reliable method for respiratory event scoring.

     

Acute effects of autoadjusting and fixed continuous positive airway pressure treatments on cardiorespiratory coupling in obese patients with obstructive sleep apnea

BackgroundTreatment with positive airway pressure devices improved signs and symptoms of obstructive sleep apnea syndrome (OSA); however, auto-adjusting positive pressure (APAP) device was not as effective as continuous positive airway pressure (CPAP) in reducing arterial blood pressure and insulin resistance. The role played by autonomic cardiac regulation remains to be clarified.We aimed to test the effects of CPAP and APAP on autonomic regulation and cardiorespiratory coupling during sleep.MethodsWe retrospectively analyzed full-night polysomnographic studies. 19 patients newly diagnosed with severe OSA (AHI > 30) and 7 obese subjects without OSA (CON) were enrolled. Each OSA subject was assigned to CPAP or APAP treatment and underwent a sleep study after 1 week of treatment. Spectral and cross-spectral analyses of heart rate variability (HRV) and respiration were performed to assess autonomic profile and coherence (K²) between respiration and HF oscillation during sleep in CPAP, APAP and CON groups.ResultsIn CPAP and CON, LFnu and LF/HF, markers of sympathetic modulation, decreased from N2 to N3 and increased during REM sleep (p < 0.001), while in APAP group, sympathetic modulation was significantly higher compared with those of CPAP and CON during all sleep stages. K² values were lower in APAP compared with those in CPAP and CON.ConclusionAPAP treatment was characterized by a greater sympathetic activation and it was associated with a lower cardio-respiratory coupling compared with CPAP. This might account for the different effects on cardiovascular risk factors induced by the two treatments.     

Initiation of therapy for obstructive sleep apnea syndrome: a randomized comparison of outcomes of telemetry-supported home-based vs. sleep lab-based therapy initiation

Purpose

Diagnosis and treatment of obstructive sleep apnea are traditionally performed in sleep laboratories with polysomnography (PSG) and are associated with significant waiting times for patients and high cost. We investigated if initiation of auto-titrating CPAP (APAP) treatment at home in patients with obstructive sleep apnea (OSA) and subsequent telemonitoring by a homecare provider would be non-inferior to in-lab management with diagnostic PSG, subsequent in-lab APAP initiation, and standard follow-up regarding compliance and disease-specific quality of life.

Methods

This randomized, open-label, single-center study was conducted in Germany. Screening occurred between December 2013 and November 2015. Eligible patients with moderate-to-severe OSA documented by polygraphy (PG) were randomized to home management or standard care. All patients were managed by certified sleep physicians. The home management group received APAP therapy at home, followed by telemonitoring. The control group received a diagnostic PSG, followed by therapy initiation in the sleep laboratory. The primary endpoint was therapy compliance, measured as average APAP usage after 6 months.

Results

The intention-to-treat population (ITT) included 224 patients (110 home therapy, 114 controls); the per-protocol population (PP) included 182 patients with 6-month device usage data (89 home therapy, 93 controls). In the PP analysis, mean APAP usage at 6 months was not different in the home therapy and control groups (4.38 ± 2.04 vs. 4.32 ± 2.28, p = 0.845). The pre-specified non-inferiority margin (NIM) of 0.3 h/day was not achieved (p = 0.130); statistical significance was achieved in a post hoc analysis when NIM was set at 0.5 h/day (p < 0.05). Time to APAP initiation was significantly shorter in the home therapy group (7.6 ± 7.2 vs. 46.1 ± 23.8 days; p < 0.0001).

Conclusion

Use of a home-based telemonitoring strategy for initiation of APAP in selected patients with OSA managed by sleep physicians is feasible, appears to be non-inferior to standard sleep laboratory procedures, and facilitates faster access to therapy.

     

Can drug-induced sleep endoscopy (DISE) predict compliance with positive airway pressure therapy? A pilot study

Purpose

Drug-induced sleep endoscopy (DISE) has been poorly explored as an examination to assess positive airway pressure (PAP) therapy in patients with obstructive sleep apnea (OSA). The present study aimed to identify by DISE possible characteristics related to low compliance with PAP therapy due to respiratory complaints.

Methods

Patients using PAP for OSA underwent DISE in two conditions: (1) baseline (without PAP) and (2) PAP (with the same mask and airway pressure used at home). We compared patients reporting low compliance to PAP due to respiratory complaints to those well-adapted to therapy. VOTE classification (assessment of velopharynx, oropharynx, tongue base, and epiglottis) and TOTAL VOTE score (the sum of VOTE scores at each anatomical site) were assessed. ROC curve analyzed the accuracy of TOTAL VOTE to predict low compliance due to persistent pharyngeal obstruction in both conditions.

Results

Of 19 patients enrolled, all presented multilevel pharyngeal obstruction at baseline condition, with no difference between groups at this study point. When PAP was added, the median VOTE value was higher in the epiglottis (P value=0.02) and tended to be higher at the velum and tongue base in the poorly adapted group; TOTAL VOTE score was also significantly increased in patients with low compliance (P value<0.001). ROC curve demonstrated that patients with TOTAL VOTE scored 2.5 or more during DISE with PAP presented a 4.6-fold higher risk for low compliance with PAP therapy due to pharyngeal obstruction (AUC: 0.88±0.07; P value<0.01; sensitivity: 77%; specificity: 83%).

Conclusions

Adding PAP during a DISE examination may help to predict persistent pharyngeal obstruction during PAP therapy.

     

Cycle length identifies obstructive sleep apnea and central sleep apnea in heart failure with reduced ejection fraction

Aim

To clarify whether unmasking of central sleep apnea during continuous positive airway pressure (CPAP) initiation can be identified from initial diagnostic polysomnography (PSG) in patients with heart failure with reduced ejection fraction (HFREF) and obstructive sleep apnea (OSA)

Materials and methods

Forty-three consecutive patients with obstructive sleep apnea and central sleep apnea (OSA/CSA) in HFREF were matched with 43 HFREF patients with OSA and successful CPAP initiation. Obstructive apneas during diagnostic PSG were then analyzed for cycle length (CL), ventilation length (VL), apnea length (AL), time to peak ventilation (TTPV), and circulatory delay (CD). We calculated duty ratio (DR) as the ratio of VL/CL and mathematic loop gain (LG).

Results

While AL was similar, CL, VL, TTPV, CD, and DR was significantly longer in patients with OSA/CSA compared to those with OSA, and LG was significantly higher. Receiver operator curves identified optimal cutoff values of 50.2 s for CL (area under the curve (AUC) 0.85, 29.2 s for VL (AUC 0.92), 11.5 s for TTPV (AUC 0.82), 26.4 s for CD (AUC 0.79), and 3.96 (AUC 0.78)) respectively for LG to identify OSA/CSA.

Conclusion

OSA/CSA in HFREF can be identified by longer CL, VL, TTPV, and CD from obstructive events in initial diagnostic PSG. The underlying mechanisms seem to be the presence of an increased LG.

     

Clinical,polysomnographic, and cephalometric features of obstructive sleep apnea with AHI over 100

Purpose

Obstructive sleep apnea (OSA) is induced by a sleep-related collapse of the upper airway in association with multiple factors. The severity of OSA is determined by the apnea-hypopnea index (AHI). Although obesity and sex differences are common factors in OSA, the level of the AHI varies to the same degree according to the age and sex and degree of obesity. However, only a few studies have evaluated AHI over 100/h, those reports did not describe why they set the AHI cutoff at 100/h. The purpose of this study was to elucidate the pathogenesis of “very” severe OSA, defined as having an AHI >?100/h.

Methods

AHI?>?100/h was set as very severe OSA (VS-OSA) in this study. As controls, moderate to severe OSA patients, matched with VS-OSA for age, sex, and body mass index (BMI), were enrolled. The findings of polysomnography and cephalography between VS-OSA and controls were compared.

Results

Eleven patients in the VS-OSA group (mean AHI 110.2/h) and 22 patients in the control group (mean AHI 41.6/h) were compared (mean age 50.2 vs 50.6, male:female 5:6 vs 10:12, mean BMI 35.4 kg/m² vs 34.5 kg/m²). There were no significant differences in the clinical characteristics. In the polysomnographic parameters, the VS-OSA group showed apnea predominance, the mean percutaneous oxygen saturation (SO₂) was significantly lower in all sleep stages, and the minimum SO₂ was significantly lower (49.0% vs 77.5%, p?=?0.002). A similar apnea duration and rather shorter hypopnea duration were shown. The time of apnea-to-arousal was significantly earlier (??0.1 s vs 0.9 s, p?=?0.003). Lung-to-finger circulation time showed no differences. The cephalometric findings showed no significant differences.

Conclusions

VS-OSA patients were more likely to have apnea predominance, desaturation when sleeping despite a similar apnea duration, and rather shorter hypopnea duration, and arousals were evoked significantly earlier.

     

Sleep staging from single-channel EEG with multi-scale feature and contextual information

Purpose

Portable sleep monitoring devices with less-attached sensors and high-accuracy sleep staging methods can expedite sleep disorder diagnosis. The aim of this study was to propose a single-channel EEG sleep staging model, SleepStageNet, which extracts sleep EEG features by multi-scale convolutional neural networks (CNN) and then infers the type of sleep stages by capturing the contextual information between adjacent epochs using recurrent neural networks (RNN) and conditional random field (CRF).

Methods

To verify the feasibility of our model, two datasets, one composed by two different single-channel EEGs (Fpz-Cz and Pz-Oz) on 20 healthy people and one composed by a single-channel EEG (F4-M1) on 104 obstructive sleep apnea (OSA) patients with different severities, were examined. The corresponding sleep stages were scored as four states (wake, REM, light sleep, and deep sleep). The accuracy measures were obtained from epoch-by-epoch comparison between the model and PSG scorer, and the agreement between them was quantified with Cohen’s kappa (?).

Results

Our model achieved superior performance with average accuracy (Fpz-Cz, 0.88; Pz-Oz, 0.85) and ? (Fpz-Cz, 0.82; Pz-Oz, 0.77) on the healthy people. Furthermore, we validated this model on the OSA patients with average accuracy (F4-M1, 0.80) and ? (F4-M1, 0.67). Our model significantly improved the accuracy and ? compared to previous methods.

Conclusions

The proposed SleepStageNet has proved feasible for assessment of sleep architecture among OSA patients using single-channel EEG. We suggest that this technological advancement could augment the current use of home sleep apnea testing.

     

Positive airway pressure therapy adherence for obstructive sleep apnea during the COVID-19 pandemic

Purpose

Positive airway pressure (PAP) adherence is a significant issue among patients with obstructive sleep apnea (OSA). However, the data are limited regarding PAP adherence during the current COVID-19 pandemic.

Methods

A cross-sectional study was conducted between February and October 2020 at the Excellence Center for Sleep Disorders, King Chulalongkorn Memorial Hospital, Bangkok, Thailand. Patients with ongoing PAP-treated OSA were recruited. Data on PAP adherence before and during the COVID-19 pandemic were collected. Furthermore, pre-test and post-test questionnaires on knowledge on COVID-19, OSA, and PAP before and after tele-education were also evaluated.

Results

Of a total 156 patients, the majority had severe OSA (72%). By self-report, there was no significant difference in PAP usage in hours per day before compared to during the pandemic (p?=?0.45), though in a subgroup with highest educational attainment (degree higher than bachelor’s), PAP usage did increase during the pandemic (mean difference 0.23?±?0.10; 95% CI 0.02–0.40, p?=?0.03). However, objective PAP usage data demonstrated a trend towards increased usage comparing before and during the pandemic (4.64?±?1.49 vs 5.12?±?1.41; mean difference 0.48?±?1.33; 95% CI 0.13–10.90, p?=?0.12). Basic knowledge was significantly improved after tele-education (p?<?0.001).

Conclusion

By objective data, there was a trend towards increased PAP usage during the COVID-19 pandemic for the entire group. In a subgroup of patients with highest educational attainment, PAP adherence increased by self-report. Tele-education appeared to improve knowledge on COVID-19, OSA, and PAP usage.

     

The effect of temazepam on assessment of severity of obstructive sleep apnea by polysomnography

Purpose

To determine the effect of temazepam on assessment of the severity of obstructive sleep apnea (OSA) by polysomnography (PSG).

Methods

Analysis of diagnostic laboratory-PSG studies was performed in OSA patients who were administered temazepam (10 mg) to facilitate sleep (“temazepam group”, n?=?73) and in OSA patients (matched for age, gender, body mass index and study date) in whom temazepam was not administered (“control group”, n?=?73). Sleep- and respiratory-related variables were compared between the groups for the (i) first 3 h of study following temazepam in the temazepam group (when peak blood concentration is expected) or following lights out in the control group, and (ii) entire study duration.

Results

Within the first 3 h, no differences in sleep-related variables were observed between the groups. Over the entire study duration, the temazepam group had a reduced total sleep time compared to the control group, likely due to the overnight sleep difficulties that led to its use. Whether measured during the first 3 h of study or over the entire study duration, no significant differences were detected between the groups for any respiratory-related variable, including apnea hypopnea index, arousal index, oxygen desaturation, apnea index, hypopnea index, and event duration. When patients were considered in terms of OSA severity, decreased arousal index was noted in the temazepam group over the entire study duration, but only in those with severe OSA.

Conclusion

Oral administration of 10 mg of temazepam during the course of PSG does not systematically affect assessment of the severity of OSA by PSG.

     

Validation of ApneaLink™ Plus for the diagnosis of sleep apnea

Purpose

The aim of this study is to evaluate the validation of ApneaLink? Plus (ALP) based on a large number of subjects in a prospective design.

Method

We recommended enrolling of 200 consecutive patients who had been referred because of habitual snoring or witnessed apnea during sleep. If consent was obtained, patients underwent standard polysomnography (PSG) and ALP evaluation simultaneously at the hospital (ALP_lab), and repeated ALP at home (ALP_home) within 1 month. The parameters of ALP were scored based on three different systems, Manual, Auto AASM, and Auto scoring systems.

Result

Among the 200 patients who were recommended for enrollment, 149 completed the study. Sensitivity was good for all three scoring systems, while specificity was poor for the Auto scoring system. The area under curve was highest for the manual scoring system and lowest for the auto scoring system, and increased as the apnea-hypopnea index (AHI) cutoff value increased from 5 to 30. Regarding agreement with PSG, the manual scoring system was most superior, followed by the Auto AASM, and Auto scoring systems. The degree of agreement between PSG and ALP was affected by sleep efficiency and the arousal index. Moderate agreement between PSG and ALP based on central apnea index was observed.

Conclusion

ALP is an accurate and reliable device for the diagnosis of OSA. Manual scoring is recommended; however, Auto AASM is also acceptable. ALP detects central sleep apnea to a certain degree. Both sleep efficiency and the arousal index affect the results of ALP.

     

Positive airway pressure therapy for chronic pain in patients with obstructive sleep apnea—a systematic review

Purpose

Obstructive sleep apnea (OSA) is prevalent in patients with chronic non-cancer pain. OSA may lead to low sleep quality and an increase in pain sensitivity. Patients reporting greater sleep impairment tend to experience higher pain intensity and vice versa. Positive airway pressure (PAP) is the current gold standard treatment for OSA. This review aims to evaluate the efficacy of PAP therapy in patients with comorbid chronic pain and OSA in influencing pain outcomes like pain intensity, tolerance, threshold, and sensitivity.

Methods

We performed a systematic literature search for studies published after 1990, utilizing the following databases: Medline, Medline In-Process/ePubs, Embase, Cochrane CENTRAL, and the Cochrane Database of Systematic Reviews. Search terms included “chronic pain,” “sleep disorders,” and “positive airway pressure.”

Results

Of 1982 initial studies, ten studies met the study inclusion criteria. Seven of these studies examined the effect of PAP therapy on chronic pain, of which five demonstrated improved pain outcomes, specifically, headache pain. The effect of PAP therapy on chronic non-headache pain was found to be inconclusive. When examining the three studies that did not involve chronic pain patients, PAP therapy effectively increased pain threshold and tolerance in two studies (p = 0.03 and p = 0.01).

Conclusion

An association exists between PAP therapy and decreased chronic headache outcomes in patients with OSA. Additionally, research shows that PAP therapy may increase pain tolerance and threshold. Future high-quality evidence is required to further investigate the association between PAP and non-headache chronic pain.

     

Gender differences in clinical and polysomnographic features of obstructive sleep apnea: a clinical study of 2827 patients

Purpose

Obstructive sleep apnea (OSA) is underdiagnosed in females due to different clinical presentation. We aimed to determine the effect of gender on clinical and polysomnographic features and identify predictors of OSA in women.

Methods

Differences in demographic, clinical, and polysomnographic parameters between 2052 male and 775 female OSA patients were compared.

Results

In female OSA patients, age (56.1 ± 9.7 vs. 50.4 ± 11.6 years, p < 0.0001) and body mass index (36.3 ± 8.6 vs. 31.8 ± 5.9 kg/m², p < 0.0001) were increased, whereas men had higher waist-to-hip ratio and neck circumference (p < 0.0001). Hypertension, diabetes mellitus, thyroid disease, and asthma were more common in females (p < 0.0001). Men reported more witnessed apnea (p < 0.0001), but nocturnal choking, morning headache, fatigue, insomnia symptoms, impaired memory, mood disturbance, reflux, nocturia, and enuresis were more frequent in women (p < 0.0001).

The indicators of OSA severity including apnea-hypopnea index (AHI) (p < 0.0001) and oxygen desaturation index (p = 0.007) were lower in women. REM AHI (p < 0.0001) was higher, and supine AHI (p < 0.0001) was lower in females. Besides, women had decreased total sleep time (p = 0.028) and sleep efficiency (p = 0.003) and increased sleep latency (p < 0.0001). In multivariate logistic regression analysis, increased REM AHI, N3 sleep, obesity, age, morning headache, and lower supine AHI were independently associated with female gender.

Conclusions

These data suggest that frequency and severity of sleep apnea is lower in female OSA patients, and they are presenting with female-specific symptoms and increased medical comorbidities. Therefore, female-specific questionnaires should be developed and used for preventing underdiagnosis of OSA.

     

Analysis of the characteristics of sleep in patients with patent foramen ovale complicated with obstructive sleep apnea

Purpose

Analyzing sleep quality and sleep structure in patients with patent foramen ovale (PFO) complicated with obstructive sleep apnea (OSA) and the interaction between OSA and PFO in sleep.

Methods

We compared patients with PFO complicated with OSA, patients with simple PFO, and controls. Pittsburgh Sleep Quality Index was used to compare sleep quality and polysomnography was used to compare sleep structure of the three groups.

Results

Compared with the control group (n = 62), PFO with OSA (n = 48) and simple PFO (n = 61) groups had more frequent occurrence of poor sleep quality (χ² = 89.901; p < 0.001). These two groups also showed decreased sleep efficiency (p < 0.010), lower percentages of REM sleep, and reduced N3 sleep (p < 0.050). The N2 sleep was prolonged (p < 0.010). The nocturnal lowest SpO₂ was lower and the oxygen desaturation index was higher (p < 0.50). Compared with the simple PFO group, the poor sleep quality was more frequent in the PFO with OSA group; sleep latency (p < 0.001) was prolonged; wake after sleep onset (p < 0.001) and arousal times (p = 0.031) were increased; and sleep micro-arousal index (p = 0.037), periodic leg movement index (p = 0.024), and apnea hypopnea index (p < 0.001) were higher in the PFO with OSA group.

Conclusion

Patients with PFO and OSA have poor sleep quality with changes in sleep stage and high occurrence rate of sleep disorders. OSA further deteriorates sleep quality and alters sleep structure in patients with PFO.

     

Clinical characteristics of Asian patients with sleep apnea with low arousal threshold and sleep structure change with continuous positive airway pressure

Purpose

Low respiratory arousal threshold (ArTH) has been observed to be prevalent in patients with obstructive sleep apnea (OSA), and is associated with poor adherence to continuous positive airway pressure (CPAP) treatment. This study aimed to examine the associations between low ArTH and clinical characteristics. The second aim was to examine sleep structure changes between diagnostic polysomnography (PSG) and CPAP titration studies.

Methods

PSG data for 3718 adults who had an apnea-hypopnea index (AHI) ≥?5 were reviewed retrospectively, as well as 206 CPAP titration studies among these participants. Participants were dichotomized into low- and high-ArTH groups according to their PSG parameters. The associations between low ArTH and clinical characteristics were examined by multivariate logistic regressions. The sleep structure changes between PSG and CPAP titration studies were examined by repeated measures ANOVA.

Results

Fifty percent of patients with OSA had low ArTH. Compared with high-ArTH patients, low-ArTH patients were less obese and composed of a higher percentage of women. In logistic regression models, low ArTH was associated with bruxism and nocturia, but not with illnesses after adjusting for AHI and body mass index. Compared with diagnostic PSG studies, low-ArTH patients had significantly decreased stage changes and increased percentage of rapid eye movement sleep during CPAP titration studies.

Conclusion

Low ArTH was prevalent in this large sample of patients with OSA. Arousal threshold was not associated with an increased risk of physical illnesses but was with certain clinical complaints. Low-ArTH patients benefited from CPAP titration study for improved sleep structure.

     

Accessibility and adherence to positive airway pressure treatment in patients with obstructive sleep apnea: a multicenter study in Latin America

Purpose

Information on access and adherence to positive airway pressure (PAP) treatment is lacking at the regional level in Latin America. This study characterized access and adherence to PAP in patients with moderate-severe obstructive sleep apnea (OSA) in Latin America.

Methods

Cross-sectional study, conducted at 9 sleep centers across Argentina, Brazil, Chile, Colombia, Mexico, and Peru. Adults diagnosed with moderate-severe OSA (apnea-hypopnea index [AHI] ≥?15/h) in the previous 12–18 months were eligible. Anthropometrics, health coverage, and OSA severity data were collected. Data on access to therapy, barriers to access, adherence, and factors related to non-compliance were obtained via standardized telephone survey.

Results

Eight hundred eighty patients (70% male, 54?±?13 years, AHI 49?±?28/h, body mass index 32?±?7 kg/m²) were included. Four hundred ninety patients (56%) initiated PAP, 70 (14%) discontinued therapy during the first year (mainly due to intolerance), and 420 (48%) were still using PAP when surveyed. Health insurance was private in 36.9% of patients, via the social security system in 31.1%, and via the state in 13.3%, and 18.7% did not have any coverage; 49.5% of patients had to pay all equipment costs. Reasons for not starting PAP were unclear or absent indication (42%), coverage problems (36%), and lack of awareness of OSA burden (14%). Patients with better adherence were older (55.3?±?13 vs 52?±?13; p?=?0.002) and had more severe OSA (AHI 51.8?±?27 vs 45.6?±?27; p?=?0.001).

Conclusions

Less than half moderate-severe OSA patients started and continue to use PAP. Unclear or absent medical indication and financial limitations were the most relevant factors limiting access to therapy.

     

Sleep architecture and obstructive sleep apnea in obese children with and without metabolic syndrome: a case control study

Purpose

Obesity and biochemical parameters of metabolic disorders are both closely related to obstructive sleep apnea (OSA). The aim of this study was to compare sleep architecture and OSA in obese children with and without metabolic syndrome.

Methods

Forty-two children with metabolic syndrome were selected as case group and 38 children without metabolic syndrome were matched for age, sex, and BMI as control group. The standardized Persian version of bedtime problems, excessive daytime sleepiness, awakenings during the night, regularity and duration of sleep, snoring (BEARS) and Children’s Sleep Habits Questionnaires were completed, and polysomnography (PSG) was performed for all study subjects. Scoring was performed using the manual of American Academy of Sleep Medicine for children. Data were analyzed using chi-square test, T test, Mann–Whitney U test, and logistic regression analysis.

Results

Non-rapid eye movement (NREM) sleep and N1 stage in the case group were significantly longer than the control group, while REM sleep was significantly shorter. Waking after sleep onset (WASO) was significantly different between two groups. Severe OSA was more frequent in the control group. Multivariate logistic regression analysis showed that severe OSA (OR 21.478, 95 % CI 2.160–213.600; P = 0.009) and REM sleep (OR 0.856, 95 % CI 0.737–0.994; P = 0.041) had independent association with metabolic syndrome.

Conclusions

Obese children with metabolic syndrome had increased WASO, N1 sleep stage, and severe OSA. But the results regarding sleep architecture are most likely a direct result of OSA severity. More longitudinal studies are needed to confirm the association of metabolic syndrome and OSA.

     

Is obstructive sleep apnea syndrome in children season dependent?

Introduction

The most common cause of obstructive sleep apnea (OSA) in children is an enlargement of tonsils and/or adenoids. Previous studies have shown that the size of adenoids and tonsils is influenced by upper respiratory tract infections and exposure to allergens. The rate of exposure to bacteria, viruses, and allergens fluctuates from season to season. Therefore, we hypothesized that the rate of polysomnograms positive for OSA may vary according to season.

Objective

The objective of this study is to determine whether the prevalence of OSA in children, as determined by polysomnography, is affected by the season during which the study was performed.

Methods

We retrospectively reviewed polysomnography tests of 296 children, ages 0–12 years, referred for suspected OSA. We compared the Obstructive Apnea Hypopnea Index (OAHI) between the seasons and the rates of abnormal tests in each season according to the degree of severity.

Results

The mean OAHI did not significantly differ among the seasons (winter, 3.0?±?5.0; spring, 3.0?±?4.9; summer, 4.0?±?6.3; fall, 3.4?±?5.7, p?=?0.183). When dividing the OAHI by levels of severity, no seasonality was found in moderate (winter, 13.8 %; spring, 6.7 %; summer, 11.7 %; fall, 14.1 %, p?=?NS) and severe OSA (winter, 8.8 %; spring, 11.2 %; summer, 10 %; fall, 7.8 %, p?=?NS). There was a small increase in the frequency of mild OSA diagnoses in the summer compared to the other seasons.

Conclusion

In this study, season does not appear to affect the rate of diagnosis of significant OSA in children. Re-evaluation during a different season is unlikely to provide different results and may postpone surgery unnecessarily.

     

Obstructive sleep apnea and respiratory center regulation abnormality

Purpose

Obstructive sleep apnea (OSA) is a complex disease in which phenotypic analysis and understanding pathological mechanisms facilitate personalized treatment and outcomes. However, the pathophysiology responsible for this robust observation is incompletely understood. The objective of the present work was to review how respiratory center regulation varies during sleep and wakeness in patients with OSA.

Data sources

We searched for relevant articles up to December 31, 2019 in PubMed database.

Methods

This review examines the current literature on the characteristics of respiratory center regulation during wakefulness and sleep in OSA, detection method, and phenotypic treatment for respiratory center regulation.

Results

Mechanisms for ventilatory control system instability leading to OSA include different sleep stages in chemoresponsiveness to hypoxia and hypercapnia and different chemosensitivity at different time. One can potentially stabilize the breathing center in sleep-related breathing disorders by identifying one or more of these pathophysiological mechanisms.

Conclusions

Advancing mechanism research in OSA will guide symptom research and provide alternate and novel opportunities for effective treatment for patients with OSA.

     

Serum levels of magnesium and their relationship with CRP in patients with OSA

Background

Low levels of magnesium (Mg) are associated with chronic inflammatory stress. Some animal studies have reported that a moderate deficiency of Mg, similar to that which occurs in humans, may increase inflammatory or oxidative stress stimulated by other factors, such as disrupted sleep or sleep deficiency.

Purpose

This cross-sectional study evaluated the relationship between serum levels of Mg and the inflammatory response in patients with a new diagnosis of obstructive sleep apnea (OSA).

Methods

This clinical, retrospective study registered 68 patients with newly diagnosed mild to severe OSA and 30 without OSA. The Apnea–Hypopnea Index (AHI), oxygen desaturation index (ODI), time until blood hemoglobin oxygen saturation <90 % (SpO₂ <90 %), and mean blood hemoglobin SpO₂ were measured. Serum levels of Mg, plasma C-reactive protein (CRP), and total sleep time (TST) by polysomnography were also measured.

Results

Mg levels were lower in patients with OSA than those in controls matched for age, sex, and body mass index (BMI). Patients with OSA had substantially higher plasma CRP concentrations than controls. A negative correlation was observed between the AHI and ODI and Mg levels. Significant differences in Mg and CRP levels were observed between patients with AHI scores of 5–15 and scores ≥30 based on OSA severity but independent of BMI. Furthermore, the AHI, ODI, TST <90 %, and mean SpO₂ significantly correlated with CRP. A significant negative correlation was observed between Mg and CRP levels (p < 0.0001).

Conclusion

Our results show that Mg levels changed depending on the presence and severity of OSA. Low levels were associated with a higher CRP concentration in patients with OSA.