Sleep Apnea Subjects Research Articles

Regional brain iron mapping in obstructive sleep apnea adults.

Obstructive sleep apnea (OSA) subjects show significant white matter injury, including myelin changes in several brain areas, potentially from impaired glial cells, contributing to increased iron levels that escalate neurodegeneration, but brain iron loads are unclear. Our aim was to examine regional brain iron load, using T2∗-relaxometry, in OSA adults before and after continuous positive airway pressure (CPAP) treatment over controls. We performed T2∗-weighted imaging using a 3.0-T MRI scanner on 35 OSA adults, who were followed after 3- and 9- mo CPAP treatment, and 67 controls. Using T2∗-weighted images, R2∗maps were calculated, normalized, and smoothed. The smoothed R2∗ maps, as well as average R2∗ values extracted from different brain regions were compared between OSA and controls using ANCOVA (covariates: age and sex) and paired t-tests in OSA adults. Multiple brain areas in OSA showed increased R2∗ values before CPAP, indicative of higher iron, over controls and included the amygdala, insula, hippocampus, cerebellum, medulla, and pons nearby areas. The R2∗ values continued to increase in multiple sites at 3-mo CPAP treatment in OSA, and those sites included the cerebellum, thalamus, and cingulate. However, after 9-mo CPAP usage, none of the brain regions showed increased R2∗ values in OSA over baseline. OSA patients show increased iron content in multiple sites over controls, which progressively increased in several sites, even after 3-mo CPAP use, and started to clear after 9-mo. The findings suggest a means for intervention to lessen brain injury by interfering with iron accumulation in OSA.

Postoperative Apnea-Hypopnea Index Prediction of Velopharyngeal Surgery Based on Machine Learning.

To investigate machine learning-based regression models to predict the postoperative apnea-hypopnea index (AHI) for evaluating the outcome of velopharyngeal surgery in adult obstructive sleep apnea (OSA) subjects. A single-center, retrospective, cohort study. Sleep medical center. All subjects with OSA who underwent velopharyngeal surgery followed for 3 to 6 months were enrolled in this study. Demographic, polysomnographic, and anatomical variables were analyzed. Compared with traditional stepwise linear regression (LR) algorithm, machine learning algorithms including artificial neural network (ANN), support vector regression, K-nearest neighbor, random forest, and extreme gradient boosting were utilized to establish the regression model. Surgical success was defined as a ≥50% reduction in AHI to a final AHI of <20 events/h. A total of 152 OSA adult patients (median [interquartile range] age = 40 [35, 48] years, male/female = 136/16) were included in this study. The ANN model achieved the highest performance with a coefficient of determination (R 2) of 0.23 ± 0.05, a root mean square error of AHI of 10.71 ± 1.01 events/h, an accuracy for outcomes classification of 81.3% ± 1.2% and an area under the receiver operating characteristic of 74.6% ± 1.9%, whereas for LR model, they were 0.094 ± 0.06, 11.61 ± 0.76 events/h, 71.7% ± 1.5% and 68.8% ± 2.9%, respectively. The machine learning-based model exhibited excellent performance for predicting postoperative AHI, which is helpful in guiding patient selections and improving surgery outcomes.

Cardiopulmonary coupling predictors of blood pressure response to positive airway pressure therapy

The effect of continuous positive airway pressure (CPAP) treatment on reducing cardiovascular disease risk in sleep apnea subjects remains inconclusive. It is plausible that pathological respiratory chemoreflex activation (high loop gain) is a predictive signal biomarker. To determine whether narrow band (e-LFCNB%) metric derived from cardiopulmonary coupling analysis is related with blood pressure reduction after CPAP. A secondary analysis of the Apnea Positive Pressure Long-term Efficacy Study (APPLES). The elevated low frequency coupling - narrow band (e-LFCNB %) metric derived from cardiopulmonary coupling analysis detects periodic breathing (as a surrogate for high loop gain), and was estimated in baseline polysomnogram. Linear regression analysis was performed to identify the potential association between e-LFCNB% of total sleep time and the observed reduction in blood pressure following the specified treatment. A total of 388 subjects received CPAP and had e-LFCNB % measurements. At 2 months, 90/322 subjects had e-LFCNB ≥ 4% at baseline. At 6 months 137/313 subjects had e-LFCNB higher than 2% at baseline. For morning systolic blood pressure, e-LFCNB ≥ 4% [β: 2.534, standard error (SE): 1.198, p: 0.035] was positively related with the extent of systolic blood pressure reductions after 2 months CPAP treatment and e-LFCNB ≥ 2% was marginally related with systolic blood pressure decrement after 6 months (β: 2.162, SE: 1.173, p: 0.066). For the morning diastolic blood pressure, e-LFCNB ≥ 2% predicted reductions at 6 months of treatment (β: 1.883, SE: 0.888, p: 0.035). e-LFCNB % (probable high loop gain) was positively related to systolic blood pressure reduction (short-term) and diastolic blood pressure reduction (longer-term), following CPAP.

Desmin gene expression is not ubiquitous in all upper airway myofibers and the pattern differs between healthy and sleep apnea subjects

BackgroundDesmin is a major cytoskeletal protein considered ubiquitous in mature muscle fibers. However, we earlier reported that a subgroup of muscle fibers in the soft palate of healthy subjects and obstructive sleep apnea patients (OSA) lacked immunoexpression for desmin. This raised the question of whether these fibers also lack messenger ribonucleic acid (mRNA) for desmin and can be considered a novel fiber phenotype. Moreover, some fibers in the OSA patients had an abnormal distribution and aggregates of desmin. Thus, the aim of the study was to investigate if these desmin protein abnormalities are also reflected in the expression of desmin mRNA in an upper airway muscle of healthy subjects and OSA patients.MethodsMuscle biopsies from the musculus uvulae in the soft palate were obtained from ten healthy male subjects and six male patients with OSA. Overnight sleep apnea registrations were done for all participants. Immunohistochemistry, in-situ hybridization, and reverse transcription–quantitative polymerase chain reaction (RT–qPCR) techniques were used to evaluate the presence of desmin protein and its mRNA.ResultsOur findings demonstrated that a group of muscle fibers lacked expression for desmin mRNA and desmin protein in healthy individuals and OSA patients (12.0 ± 5.6% vs. 23.1 ± 10.8%, p = 0.03). A subpopulation of these fibers displayed a weak subsarcolemmal rim of desmin accompanied by a few scattered mRNA dots in the cytoplasm. The muscles of OSA patients also differed from healthy subjects by exhibiting muscle fibers with reorganized or accumulated aggregates of desmin protein (14.5 ± 6.5%). In these abnormal fibers, the density of mRNA was generally low or concentrated in specific regions. The overall quantification of desmin mRNA by RT–qPCR was significantly upregulated in OSA patients compared to healthy subjects (p = 0.01).ConclusionsOur study shows evidence that muscle fibers in the human soft palate lack both mRNA and protein for desmin. This indicates a novel cytoskeletal structure and challenges the ubiquity of desmin in muscle fibers. Moreover, the observation of reorganized or accumulated aggregates of desmin mRNA and desmin protein in OSA patients suggests a disturbance in the transcription and translation process in the fibers of the patients.

Association of the TNF-α-308G>A gene polymorphism with left ventricular geometry and functional abnormalities in obstructive sleep apnea subjects.

Tumor necrosis factor-α (TNF-α) can induce left ventricular remodeling. In this study, we investigated whether the TNF-α-308G>A polymorphism is associated with left ventricular geometry (LVG) and left ventricular functional abnormalities in obstructive sleep apnea (OSA) subjects. Two hundred and seventy-eight subjects were enrolled. Echocardiography and genetic data were assessed in all patients. Geometric patterns of the left ventricle were determined from the relative wall thickness and left ventricular mass index (LVMI). Genetic analysis for the TNF-α-308G>A SNP rs1800629 was identified by Sanger sequencing. The correlations of the TNF-α-308G>A polymorphism with LVG and left ventricular function were analyzed by difference analysis and logistic regression. The chi-square test showed that there were differences in genotype distributions among the four groups (p = 0.033), such that the frequency of GA+AA genotypes was significantly higher in the concentric hypertrophy group than in the normal geometry group (p < 0.05). Independent sample T tests showed that the GA+AA genotypes had higher IVST, LVPWT, LVMI, E/e' values, and lower e' values than those of the GG genotype (p < 0.05). Logistic regression analysis showed that the TNF-α-308G>A polymorphism was independently correlated with eccentric hypertrophy (OR = 2.456, p = 0.047) and concentric hypertrophy (OR = 2.456, p = 0.047). In OSA patients, the TNF-α-308G>A polymorphism was linked to LVG and abnormal left ventricular diastolic function, suggesting that the TNF-α-308G>A polymorphism may have an important influence on LVG alterations.

Retrospective Analysis of the Polysomnographic and Airway Changes in Obstructive Sleep Apnea (OSA) Subjects Who Underwent Maxillomandibular Advancement (MMA) Surgery

Retrospective Analysis of the Polysomnographic and Airway Changes in Obstructive Sleep Apnea (OSA) Subjects Who Underwent Maxillomandibular Advancement (MMA) Surgery

0487 The effect of negative pressure ventilation on airflow in obstructive sleep apnea subjects undergoing drug induced sleep endoscopy

Abstract Introduction Drug induced sleep endoscopy (DISE) is used to visually characterize pharyngeal airway collapse in obstructive sleep apnea (OSA) to help determine appropriate patients for OSA surgery. The procedure has grown in complexity with the addition of airflow recording and continuous positive airway pressure (CPAP) titration to obtain additional measures of airway collapsibility. Lung volume can also influence airway collapse in OSA but is not evaluated as part of routine DISE. The purpose of this study is to characterize the relationship between changes in lung volume and upper airway collapse during DISE to gain further insight into factors contributing to airway collapse and their potential roles in influencing surgical decision making. Methods This study is an ongoing IRB approved prospective clinical trial assessing the effects of negative pressure ventilation on airway collapse during DISE. Enrolled patients first undergo DISE evaluation per clinical routine including a CPAP titration. CPAP is then held at a level where patients exhibit stable flow limitation. A negative pressure ventilator shell is placed over the torso of the body and negative pressures of up to -25cmH2O are applied to expand the chest and increase lung volume. Changes to nasal airflow and tidal volume are evaluated. The negative pressure ventilator is then released and changes to airflow back to baseline are recorded. Results Between 6/30/2022 and 11/30/2022, 5 patients completed the study. There were 4 men and 1 woman with an average age of 60 years, BMI of 26.67kg/m2, and apnea-hypopnea index (AHI) of 44.44 events/hr. Average peak inspiratory flow increased from 8.38L/min to 13.78L/min and average tidal volumes increased from 155mL to 269mL on negative pressure ventilation. Conclusion Increases in lung volume from negative pressure ventilation during DISE can improve airflow and tidal volume suggesting that changes in lung volume can influence the severity of upper airway collapse. Further study to better characterize this relationship can help add additional diagnostic information regarding airway collapse characteristics to provide better informed surgical decisions and develop new interventions. Support (if any) Supported by the National Center for Advancing Translational Sciences (NCATS) of the National Institutes of Health (NIH) under Award Numbers UL1TR002378 and KL2TR002381

0723 Slow wave activity surrounding K-complexes is associated with long-term all-cause mortality in a large community-dwelling cohort

Abstract Introduction Sleep fragmentation is thought to be associated with adverse long-term consequences including mortality. However, conventional metrics of sleep fragmentation such as time spent in non-REM, REM sleep stages have been inconsistently associated with long-term consequences of sleep fragmentation. Recent studies suggest that morphological features of K-complexes might better describe sleep fragmentation as they are sensitive to effects of sleep disruption and better correlate with short-term outcomes such as daytime sleepiness. We previously demonstrated that the slow wave activity (SWA) surrounding K-complexes (∆SWAK) was a strong predictor of sleepiness in a cohort of sleep apnea subjects, mediated in part by its association with sleep fragmentation, however its association with long-term consequences of sleep fragmentation is not well known. Methods We analyzed nocturnal polysomnography (NPSG) data from Sleep Heart Health Study (1995-1998), a well-characterized cohort examining the cardiovascular consequences of sleep-disordered breathing. The primary quantitative EEG (C3-A2) metrics were: SWA (%relative power in 0.5-4 Hz), K-complex density (number/min of N2), and ∆SWAK. K-complexes were detected automatically using previously published open-source method (DETOKS, Parekh et. al., 2015) during stage N2 of sleep only. All EEG metrics were divided into quartiles to explore potential non-linear associations. Death from any cause up until 2011 (mean follow up of 11 years) was the primary outcome. Cox-regression models were used to assess the relationship between EEG metrics and all-cause mortality. Results After accounting for missing data, 3,909 NPSG’s with at least 6h of usable EEG were available for analysis (age=64±11 yrs., 53.4% female). In multivariate Cox-regression models adjusted for age, gender, race, severity of sleep apnea, total sleep time, time spent in stage N2, and smoking, all-cause mortality was significantly associated with the highest quartile of SWA (HR_q4=0.77 [0.6-0.9], p=0.01), highest two quartiles of ∆SWAK (HR_q3=0.8 [0.6-0.9], p=0.04; HR_q4=0.6 [0.5-0.8], p&amp;lt; 0.001). Conclusion Quantitative EEG measures predict mortality in a large community-dwelling cohort. Specifically, slow-wave activity surrounding K-complexes appear to be strongly associated with all-cause mortality beyond the effect of known covariates. Combined with our previous studies, our data suggest that slow-wave specific EEG measures are predictive of short- and long-term consequences of sleep fragmentation. Support (if any) AASM Foundation BS-233-20, NIH-K25HL151912, R21HL165320

The clinical influence of nasal surgery on PAP compliance and optimal application among OSA subjects uncomfortable with PAP device wear

This study aimed to evaluate the alteration of PAP compliance after nasal surgery and to determine the optimal indications of nasal surgery in obstructive sleep apnea (OSA) subjects. Among OSA subjects using PAP devices, 29 subjects who underwent septoturbinoplasty due to nasal obstruction were included and their pre- and postoperative medical and PAP records were reviewed retrospectively. Postoperative autoPAP usage data was further assessed by grouping the compliance (the percentage of days with usage ≥ 4 h) data (group 1: the good compliance group; group 2: the poor compliance group). The data showed that 56% of subjects in group 1 complained of nasal obstruction as the only barrier to using a PAP device and about 89% reported experiencing the efficacy of PAP usage. Both the mean and peak average PAP pressures were significantly reduced in group 1 following nasal surgery. Group 2 had multiple subjective problems that interfered with wearing a PAP device and reported a lack of experiencing the efficacy of PAP usage. Preoperative nasal cavity volume values were smaller and absolute blood eosinophil counts were significantly lower in group 1. The current data demonstrate that nasal surgery might increase the compliance of PAP device wear in OSA subjects who complained of only nasal obstruction as a barrier to wearing PAP and who had small nasal cavity volumes combined with allergic inflammation.

Saliva Analysis of pH and Antioxidant Capacity in Adult Obstructive Sleep Apnea Patients.

Background: Obstructive sleep apnea syndrome (OSAS) may be associated with and activates the stress response system, and variation in the physiological antioxidant capacity of body fluids. Our aim was to evaluate the variation of pH and antioxidant capacity on the saliva of obstructive sleep apnea subjects (OG) compared to a control group (CG). Method: Fifty subjects with moderate/severe OSAS were recruited in Tor Vergata Hospital and compared with 20 healthy subjects CG. The buffer and the antioxidant capacity of the samples were quantified measuring the pH and the percentage of total salivary antioxidant capacity (%TAC), which refers to the reduced glutathione salivary concentration (GSH). Moreover, the protein concentration and the gelatinolytic activity of metalloproteinases were quantified. Results: The data showed that the pH value is slightly more alkaline in OSAS subjects; however, it is not directly related to the severity of OSAS. The %TAC was found to be significantly reduced by 86.2% in the OG. Proteins of saliva from the OG were found 1.5 times more concentrated than in the healthy sample. The gelatinolytic activity of metalloproteinases of healthy and OSA did not show statistically significant changes. Conclusions: The salivary samples from OSAS compared to CG show an alteration of the oxidative state, the pH buffering power, and protein concentrations, inducing conditions that can easily evolve chronic gingivitis. Further investigations are necessary to evaluate the feasibility of using salivary fluid for the early diagnosis of oral or systemic problems in OSAS subjects.

Sleep body position correlates with cognitive performance in middle age obstructive sleep apnea subjects.

Sleep body position correlates with cognitive performance in middle age obstructive sleep apnea subjects.

Optimal application of soft-palate webbing flap pharyngoplasty combined with nasal surgery for surgical treatment of primary snoring and obstructive sleep apnea

BackgroundExcessive collapse of the soft palate and lateral pharyngeal wall narrowing are established causes of loud snoring and sleep apnea in subjects with obstructive sleep apnea (OSA). Therefore, delicate surgical techniques are needed to reshape the soft palate and create sufficient tension in the lateral pharyngeal wall. This study aimed to determine the therapeutic outcome and favorable indications of soft-palate webbing flap pharyngoplasty in subjects with OSA and primary snoring.MethodsA total of 174 subjects who underwent soft-palate webbing flap pharyngoplasty combined with uvulopalatal flap and septoturbinoplasty from August 2015 to February 2020 were included in this study. Medical records, including pre- and postoperative sleep parameters, were retrospectively reviewed. The primary outcome measure was the degree of improvement in AHI after surgery. Other outcomes were differences in surgical response rates, subjective visual analog score (VAS) for snoring, sleep quality, and complications.ResultsPolysomnographic results showed that apnea–hypopnea index (AHI) scores were significantly reduced from 39.6 ± 6.1 to 22.9 ± 3.6 following soft-palate webbing flap pharyngoplasty in 59 subjects, and overall success and response rates of this technique were analyzed with 71%. We found that the successful outcomes were observed in 50% of mild (n = 12) and 56% of moderate (n = 16) subjects with OSA subjects due to lateral pharyngeal wall collapse. The success rate of soft-palate webbing flap pharyngoplasty was relatively higher in subjects with mild and moderate OSA than those with severe OSA. Additionally, the mean VAS snoring scale was 4.7 and subjects’ primary snoring intensity significantly improved to 2.9 after soft-palate webbing flap pharyngoplasty. Subjective symptoms such as daytime sleepiness and sleep quality also showed improvement. Most complications were found to be minimal and improved by 1 month after the operation.ConclusionOur data demonstrate that soft-palate webbing flap pharyngoplasty is an effective treatment for OSA and primary snoring and may be a promising technique to reduce lateral pharyngeal wall collapse.

Population screening for atrial fibrillation in subjects with sleep apnea

Abstract Background Sleep apnea is highly associated with atrial fibrillation (AF), resulting in increased risk of mortality. However, early identification and intervention of AF is limit among subjects with sleep apnea as often asymptomatic. Objective The present study aimed to investigate the occurrence of AF in subjects at high risk for sleep apnea with smart technology. Methods The photoplethysmographic (PPG)-based smart devices (wristband: Huawei Band B6, Honor Band 6); wristwatch: Huawei Watch GT2, Huawei Watch FIT, Honor Watch GS Pro, Honor Watch ES, Honor MagicWatch2, Huawei Technologies Co., Ltd., Shenzhen, China) were used for screening AF across China, which has been validated in Pre-mAFA (Huawei Heart Study). The PPG-based detecting sleep apnea has been developed. High-risk sleep apnea was defined as more than 80% monitoring measures with Apnoea–Hypopnoea Index (AHI) ≥30 during the sleep, monitored by PPG-based smart devices. The identified AF and high-risk sleep apnea were further confirmed by health providers with clinical evaluation, electrocardiogram, 24-hour Holter, or polysomnograph, respectively. Results There were 187,933 subjects (38.18±10.77 years, 90.88% male) who recruited for screening sleep apnea between December 2019, and December 2020. Among these, 9088 (4.84%,42.62±9.27 years, 98.13% male) were identified as high-risk sleep apnea, with average AHI of 27.99 (interquartile range [IQR]: 19.27–36.40). Among those, 184,970 (of 187,933, 98.42%)subjects monitored sleep apnea and pulse rhythm with PPG-smart devices, with 8837 subjects of high-risk sleep apnea. Ninety-three (93/8837, 1.05%) AF were identified among those at high-risk sleep apnea, which was higher compared to those without sleep apnea (203/54916, 0.37%, p&amp;lt;0.001). With the increased risk for sleep apnea, identified AF raised (normal-, low-, moderate-, high-risk: 0.37%, 0.72%, 0.95%, and 1.05%, p&amp;lt;0.001, Figure 1). Compared with non-AF subjects, subjects with identified AF were at much high -risk sleep apnea (8744/183736, 4.76% vs. 93/1234, 7.54%, p&amp;lt;0.001). In multivariate analysis, high-risk sleep apnea increased 5.36 (95% CI: 3.43–8.37)fold risk of AF, after adjustment of age, sex, body mass index, hypertension, diabetes mellitus, coronary artery disease, heart failure, and hyperthyroidism. The sensitivity analysis of the high-risk sleep apnea subjects (n=460,42.41±8.04 years, 98.70% male), which further confirmed with the diagnosis of sleep apnea by doctors and polysomnography, demonstrated the similar proportion identified AF (5/460, 1.09%). Conclusions In this population-based screening study, high-risk sleep apnea increased more than five-fold risk for AF, highlighting the compelling need for effective intervention of AF. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Health Care of China (20BJZ26)

Classification of Sleep Apnea Based on Sub-Band Decomposition of EEG Signals.

To classify between normal and sleep apnea subjects based on sub-band decomposition of electroencephalogram (EEG) signals. This study comprised 159 subjects obtained from the ISRUC (Institute of System and Robotics—University of Coimbra), Sleep-EDF (European Data Format), and CAP (Cyclic Alternating Pattern) Sleep database, which consists of normal and sleep apnea subjects. The wavelet packet decomposition method was incorporated to categorize the EEG signals into five frequency bands, namely, alpha, beta, delta, gamma, and theta. Entropy and energy (non-linear) for all bands was calculated and as a result, 10 features were obtained for each EEG signal. The ratio of EEG bands included four parameters, including heart rate, brain perfusion, neural activity, and synchronization. In this study, a support vector machine with kernels and random forest classifiers was used for classification. The performance measures demonstrated that the improved results were obtained from the support vector machine classifier with a kernel polynomial order 2. The accuracy (90%), sensitivity (100%), and specificity (83%) with 14 features were estimated using the data obtained from ISRUC database. The proposed study is feasible and seems to be accurate in classifying the subjects with sleep apnea based on the extracted features from EEG signals using a support vector machine classifier.

High Sensitive C-Reactive Protein as a Marker of Systemic Inflammation in Male Coronary Artery Disease with Obstructive Sleep Apnea

Background: High Sensitive C-Reactive Protein (hsCRP) is an acute phase protein which may be used as a sensitive marker for increased risk of cardiovascular events in Obstructive Sleep Apnea (OSA) subjects. Methods: This was a cross-sectional study to evaluate hsCRP as a sensitive marker for cardiovascular events in Obstructive Sleep Apnea (OSA) subjects. Subjects were recruited at Medical Check-up Department, Siloam Hospital Lippo Village, Karawaci, Tangerang between January and December 2018. This study included 74 OSA men whose blood were collected after fasting prior to hsCRP test. The diagnosis of Coronary Artery Disease (CAD) was determined by previous medical examinations using treadmill test, CT angiography and cardiac catheterization. Results: There were 39 people (52,7%) who were diagnosed with CAD out of 74 OSA men. The cut off point for hsCRP more than 0,42 was a marker for increased risk for CAD with Odds Ratio (OR)=7,43, Relative Risk (RR)=88%, sensitivity=17,95%, specificity=97,14%, Likelihood ratio (LR+) 6,28 and LR(-) 0,84. Conclusion: HsCRP with cut-off point >0,42 could be used as a marker of increased risk of cardiovascular case in male OSA subjects.

Clinical safety and hemodynamic, cardiac autonomic and inflammatory responses to a single session of inspiratory muscle training in obstructive sleep apnea.

To determine clinical safety and cardiovascular, cardiac autonomic and inflammatory responses to a single session of inspiratory muscle training (IMT) in obstructive sleep apnea (OSA) subjects. In a randomized controlled trial individuals of both sexes, aged between 30 and 70 years old with diagnosis of moderate to severe OSAwere enrolled. Volunteers with OSA(n = 40) performed an IMT session with three sets of 30 repetitions with a 1-min interval between them. The IMT group (n = 20) used a load of 70% of the maximum inspiratory pressure (MIP), and the placebo group (n = 20) performed the IMT without load. Measurements of systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), heart rate variability (HRV), and inflammatory markers were performed pre, post-immediate and 1 h after the IMT session. No differences were shown in SBP, DBP, HRV, or inflammatory markers at any of the intervals analyzed. However, HR in the IMT group was lower ​​1 h after the IMT session compared to the pre-session values ​​(p = 0002). HR was higher in the placebo group when comparing pre × post-immediate (p < 0.001). HR decreased after the first hour in relation to the pre (p < 0.001) and post-immediate (p < 0.001) values. IMT sessions promote discreet hemodynamic, cardiac autonomic and inflammatory responses. Therefore, IMT is considered clinically safe and can be performed at home, guided but unsupervised, with lower cost and greater adherence to exercise program for subjects withOSA.

Decreased sample entropy during sleep-to-wake transition in sleep apnea patients

Objective. This study aimed to prove that there is a sudden change in the human physiology system when switching from one sleep stage to another and physical threshold-based sample entropy (SampEn) is able to capture this transition in an RR interval time series from patients with disorders such as sleep apnea. Approach. Physical threshold-based SampEn was used to analyze different sleep-stage RR segments from sleep apnea subjects in the St. Vincents University Hospital/University College Dublin Sleep Apnea Database, and SampEn differences were compared between two consecutive sleep stages. Additionally, other standard heart rate variability (HRV) measures were also analyzed to make comparisons. Main results. The findings suggested that the sleep-to-wake transitions presented a SampEn decrease significantly larger than intra-sleep ones (P < 0.01), which outperformed other standard HRV measures. Moreover, significant entropy differences between sleep and subsequent wakefulness appeared when the previous sleep stage was either S1 (P < 0.05), S2 (P < 0.01) or S4 (P < 0.05). Significance. The results demonstrated that physical threshold-based SampEn has the capability of depicting physiological changes in the cardiovascular system during the sleep-to-wake transition in sleep apnea patients and it is more reliable than the other analyzed HRV measures. This noninvasive HRV measure is a potential tool for further evaluation of sleep physiological time series.

Nasal versus oronasal mask in patients under auto-adjusting continuous positive airway pressure titration: a real-life study.

Mask type (nasal versus oronasal) can affect the optimal pressure required to correct the apnea/hypopnea index (AHI) in obstructive sleep apnea (OSA) subjects treated with CPAP. Our objective was to evaluate if mask type influenced CPAP titration outcomes in OSA patients. A retrospective study of individuals with a baseline AHI ≥ 15.0/h, who received an auto-adjusting CPAP titrating device (S9 AutoSet ResMed®) in a sleep-lab setting. The mask type oronasal (OM) or nasal (NM) was always selected by the patients. Optimal pressure requirements, leak, and residual AHI were compared based on mask type. Overall, 436 patients were included: 283 with NM (64.9%) and 153 with OM (35.1%). At baseline, NM and OM cohorts had similar AHI (p = 0.160). Patients allocated to the OM cohort had a higher 95th percentile pressure, a higher 95th percentile leak, and a higher residual AHI than those with a NM: pressure requirement: 12.9cm H2O (IQR: 10.6-15.0) versus 10.7cm H2O (IQR: 9.2-12.3); leak: 21.6 L/min (IQR: 9.6-37.2) versus 9.6 L/min (IQR: 3.6-19.2); and residual AHI: 4.9/h (IQR: 2.4-10.2) versus 2.2/h (IQR: 1.0-4.4), respectively (p < 0.001 for all). CPAP mask type based on individual preferences exerts profound effects on optimal CPAP pressures and efficacy. Patients titrated with OM showed higher pressure requirements, had higher a leak, and higher residual AHI when compared to NM, which may adversely impact treatment adherence and other health outcomes.

Effects of central apneas on sympathovagal balance and hemodynamics at night: impact of underlying systolic heart failure

BackgroundIncreased sympathetic drive is the key determinant of systolic heart failure progression, being associated with worse functional status, arrhythmias, and increased mortality. Central sleep apnea is highly prevalent in systolic heart failure, and its effects on sympathovagal balance (SVB) and hemodynamics might depend on relative phase duration and background pathophysiology.ObjectiveThis study compared the effects of central apneas in patients with and without systolic heart failure on SVB and hemodynamics during sleep.MethodsDuring polysomnography, measures of SVB (heart rate and diastolic blood pressure variability) were non-invasively recorded and analyzed along with baroreceptor reflex sensitivity and hemodynamic parameters (stroke volume index, cardiac index, total peripheral resistance index). Data analysis focused on stable non-rapid eye movement N2 sleep, comparing normal breathing with central sleep apnea in subjects with and without systolic heart failure.ResultsTen patients were enrolled per group. In heart failure patients, central apneas had neutral effects on SVB (all p > 0.05 for the high, low, and very low frequency components of heart rate and diastolic blood pressure variability). Patients without heart failure showed an increase in very low and low frequency components of diastolic blood pressure variability in response to central apneas (63 ± 18 vs. 39 ± 9%; p = 0.001, 43 ± 12 vs. 31 ± 15%; p = 0.002). In all patients, central apneas had neutral hemodynamic effects when analyzed over a period of 10 min, but had significant acute hemodynamic effects.ConclusionEffects of central apneas on SVB during sleep depend on underlying systolic heart failure, with neutral effects in heart failure and increased sympathetic drive in idiopathic central apneas.

Intranasal oxytocin increases respiratory rate and reduces obstructive event duration and oxygen desaturation in obstructive sleep apnea patients: a randomized double blinded placebo controlled study

BackgroundActivation of the oxytocin network has shown benefits in animal models of Obstructive Sleep Apnea (OSA) as well as other cardiorespiratory diseases. We sought to determine if nocturnal intranasal oxytocin administration could have beneficial effects in reducing the duration and/or frequency of obstructive events in obstructive sleep apnea subjects. MethodsTwo sequential standard “in-lab” polysomnogram (PSG) sleep studies were performed in patients diagnosed with OSA that were randomly assigned to initially receive either placebo or oxytocin (40 i.u.) administered intranasally in this double blinded randomized placebo controlled study. Changes in cardiorespiratory events during sleep, including apnea and hypopnea durations and frequency, risk of event-associated bradycardias, arterial oxygen desaturation and respiratory rate were assessed in 2 h epochs following sleep onset. Oxytocin significantly decreased the duration of obstructive events, as well as the oxygen desaturations and incidence of bradycardia that were associated with these events. Notably, oxytocin increased respiratory rate during non-obstructive periods. There were no significant changes in sleep architecture and no adverse effects were reported. ConclusionsOxytocin administration can benefit OSA subjects by reducing the duration and adverse consequences of obstructive events. Oxytocin could also be beneficial in situations involving respiratory depression as oxytocin increased respiratory rate. Additional studies are needed to further understand the mechanisms by which oxytocin promotes these changes in cardiorespiratory function. The long-term efficacy and optimal dose of intranasal oxytocin treatment should also be determined in OSA subjects.ClinicalTrials.gov NCT03148899.