Phenotype-based and Self-learning Inter-individual Sleep Apnea Screening with a Level IV Monitoring System

Purpose: We propose a phenotype-based artificial intelligence system that can self-learn and is accurate for screening purposes, and test it on a Level IV monitoring system. Methods: Based on the physiological knowledge, we hypothesize that the phenotype information will allow us to find subjects from a well-annotated database that share similar sleep apnea patterns. Therefore, for a new-arriving subject, we can establish a prediction model from the existing database that is adaptive to the subject. We test the proposed algorithm on a database consisting of 62 subjects with the signals recorded from a Level IV wearable device measuring the thoracic and abdominal movements and the SpO2. Results: With the leave-one cross validation, the accuracy of the proposed algorithm to screen subjects with an apnea-hypopnea index greater or equal to 15 is 93.6%, the positive likelihood ratio is 6.8, and the negative likelihood ratio is 0.03. Conclusion: The results confirm the hypothesis and show that the proposed algorithm has great potential to screen patients with SAS

Sex, stress and sleep apnoea: decreased susceptibility to upper airway muscle dysfunction following intermittent hypoxia in females

Obstructive sleep apnoea syndrome (OSAS) is a devastating respiratory control disorder more common in men than women. The reasons for the sex difference in prevalence are multifactorial, but are partly attributable to protective effects of oestrogen. Indeed, OSAS prevalence increases in post-menopausal women. OSAS is characterized by repeated occlusions of the pharyngeal airway during sleep. Dysfunction of the upper airway muscles controlling airway calibre and collapsibility is implicated in the pathophysiology of OSAS, and sex differences in the neuro-mechanical control of upper airway patency are described. It is widely recognized that chronic intermittent hypoxia (CIH), a cardinal feature of OSAS due to recurrent apnoea, drives many of the morbid consequences characteristic of the disorder. In rodents, exposure to CIH-related redox stress causes upper airway muscle weakness and fatigue, associated with mitochondrial dysfunction. Of interest, in adults, there is female resilience to CIH-induced muscle dysfunction. Conversely, exposure to CIH in early life, results in upper airway muscle weakness equivalent between the two sexes at 3 and 6 weeks of age. Ovariectomy exacerbates the deleterious effects of exposure to CIH in adult female upper airway muscle, an effect partially restored by oestrogen replacement therapy. Intriguingly, female advantage intrinsic to upper airway muscle exists with evidence of substantially greater loss of performance in male muscle during acute exposure to severe hypoxic stress. Sex differences in upper airway muscle physiology may have relevance to human OSAS. The oestrogen–oestrogen receptor α axis represents a potential therapeutic target in OSAS, particularly in post-menopausal women

Can Weight Loss Improve the Cardiovascular Outcomes of Patients with Obesity and Obstructive Sleep Apnea?

Cardiovascular events are the primary cause of mortality in patients with obstructive sleep apnea and obesity. The rising prevalence of obstructive sleep apnea in recent decades has been linked to increasing rates of obesity. Obstructive sleep apnea has also been linked with many different cardiovascular diseases including coronary artery disease, stroke, heart failure, hypertension, and atrial fibrillation. Obesity is an increasing health concern globally, in part because obesity complications such as hypertension, diabetes, and obstructive sleep apnea increase the risk of cardiovascular diseases. More than 10% weight loss may be required to prevent or reverse obesity complications. Treatment approaches to obesity include nutritional therapy, exercise therapy, pharmacotherapy, and surgical therapies. This review intends to identify the effects of weight loss on cardiovascular outcomes in patients with obesity and obstructive sleep apnea. Despite the strong association between cardiovascular diseases and obstructive sleep apnea, randomized trials have failed to demonstrate that treatment of obstructive sleep apnea reduces cardiovascular events, even in patients with established cardiovascular diseases. Weight loss in patients with obstructive sleep apnea improves HbA1c, systolic blood pressure, HDL cholesterol, and triglycerides, but thus far no changes in cardiovascular events have been shown. The combination of weight loss with continuous positive airway pressure (CPAP) appears more beneficial than either treatment in isolation. Large well-controlled trials in patients with obstructive sleep apnea to assess the effects of different weight reduction programs on cardiovascular disease are still needed

Ocena zaburzeń oddychania w czasie snu z wykorzystaniem rejestracji holterowskiej u pacjentów z tętniczym nadciśnieniem płucnym oraz nadciśnieniem płucnym wtórnym do dysfunkcji lewej komory serca

Introduction. Sleep-disordered breathing (SDB) affects approximately 2–12% of the general population and the prevalence among patients with heart failure due to left ventricular dysfunction (LV–HF) is even higher. SDB is an important determinant of worse clinical outcomes in such patients. In contrast, the prevalence of SDB in pulmonary arterial hypertension (PAH) and its implications remain unclear. The purpose of this study was to compare relations between estimated apnea-hypopnoea index (eAHI) and clinical parameters in patients with LV–HF and PAH, with particular attention to the consequences of SDB.Material and methods. Eighty-one patients were screened for SDB using commercial Holter electrographic monitoring software that allowed evaluation of eAHI. The study population consisted of 39 LV–HF patients and 42 PAH patients. Results. While similar N-terminal pro B-type natriuretic peptide (NT-proBNP) levels were noted in both groups, LV–HF patients were characterized by higher age (63 vs. 50 years, respectively, p < 0.001), higher proportion of males (87% vs. 40%, p < 0.0001), and higher eAHI (24 vs. 14, p < 0.001) and body mass index (BMI) (28 vs. 25 kg/m2, p < 0.001) values compared to the PAH group. The prevalence of SDB, defined as eAHI > 15, was 64% in the LV–HF group and 36% in the PAH group. Parameters of time domain heart rate variability (HRV) analysis were lower in PAH vs. LV–HF. Patients with LV–HF had more ventricular arrhythmias than patients with PAH. In the LV–HF group, eAHI correlated positively with NT-proBNP level, and negatively with left ventricular ejection fraction and the mean heart rate. The median eAHI was 18.7, and patients with eAHI above the median had more supraventricular arrhythmias. In the PAH group, a negative correlation between eAHI and age was found. In the subgroup with eAHI < 15, rMSSD values were higher and idiopathic PAH predominated. The median eAHI was 8.4, and patients with eAHI above the median were younger and had higher BMI values. Conclusions. Sleep-disordered breathing was more frequent and eAHI was higher in patients with LV–HF compared to those with PAH, although it was present in more than one third of patients in the latter group. Higher eAHI values indicated more severe hemodynamic dysfunction in patients with LV–HF. In the PAH group, higher eAHI was associated with clinical presentation at a younger age. Patients with PAH seem to have worse HRV parameters compared to patients with left ventricular dysfunction.Wstęp. Zaburzenia oddychania w czasie snu (SDB) dotyczą 2–12% ogólnej populacji; jeszcze wyższy odsetek obserwuje się wśród pacjentów z niewydolnością serca spowodowaną dysfunkcją lewej komory (LV–HF). Występowanie SDB w tętniczym nadciśnieniem płucnym (PAH) oraz jego implikacje kliniczne pozostają niejasne. Celem pracy było porównanie relacji między oszacowanym wskaźnikiem bezdechu sennego (eAHI) a parametrami klinicznymi pacjentów z LV–HF i PAH, z uwzględnieniem konsekwencji obecności bezdechu sennego.Materiał i metody. Do badania włączono 81 chorych, u których wykonano 24-godzinne monitorowanie elektrokardiograficzne metodą Holtera w celu obliczenia eAHI. Populację podzielono na dwie grupy — 39 chorych z LV–HF o etiologii wieńcowej oraz 42 chorych z PAH.Wyniki. W grupie LV–HF dominowali mężczyźni (87% v. 40% w grupie PAH; p < 0,0001), w starszym wieku (63 v. 50 lat w grupie PAH; p < 0,001), z wyższymi wartościami wskaźnika masy ciała (BMI) (28 v. 25 kg/m2; p < 0,001) oraz niższą frakcją wyrzutową lewej komory (LVEF) (33 v. 56%; p < 0,000001), choć grupy charakteryzowała podobna średnia wartość stężenia N-końcowego fragmenty propetydu natriuretycznego typu B (NT-proBNP). Zaburzenia oddychania w czasie snu, zdefiniowane jako eAHI ponad 15, stwierdzono u 64% chorych z LV–HF i u 36% pacjentów z PAH. Wyższe wartości eAHI występowały w grupie LV–HF (24 v. 14; p < 0,001). Pacjenci z LV–HF cechowali się obecnością licznych arytmii komorowych, a przy wartościach eAHI powyżej mediany (> 18,7) potwierdzono zwiększoną częstość występowania arytmii nadkomorowej. W PAH obserwowano istotnie obniżone parametry czasowej zmienności rytmu zatokowego (HRV). W grupie LV–HF wykazano korelację eAHI z wartościami NT-proBNP i odwrotną korelację z LVEF oraz średnią dobową częstotliwością pracy serca. Z kolei eAHI w grupie chorych z PAH nie korelowało z NT-proBNP ani LVEF, ale było odwrotnie proporcjonalne do wieku. Wśród chorych z PAH i wartościami eAHI poniżej 15 przeważali pacjenci z PAH o etiologii idiopatycznej, z wyższymi wartościami rMSSD. Pacjentów z PAH i wartościami eAHI powyżej mediany (> 8,4) charakteryzowały młodszy wiek oraz wyższe wartości BMI.Wnioski. Zaburzenia oddychania podczas snu u pacjentów z PAH nie były tak częste jak u chorych z LV–HF, ale dotyczyły więcej niż 1/3 populacji. Wyższe wartości eAHI u chorych z LV–HF wskazują na zaawansowaną dysfunkcję hemodynamiczną. U pacjentów z PAH obecność SDB wiąże się z zachorowaniem w młodszym wieku i wskazuje na istotną dysregulację w zakresie autonomicznej kontroli pracy serca

Obturacyjny bezdech senny jako czynnik ryzyka chorób układu krążenia

Obstructive sleep apnea (OSA) is a widely prevalent disorder. The relationship between cardiovascular disease and OSA has been well established. There isincreasing evidence suggesting that common comorbidities such as myocardial infarction, cardiac arrhythmias or stroke primarily ascribed to hypertension only, may be in fact caused by concomitant OSA. While OSA is implicated in higher cardiovascular morbidity, its treatment appears to lower this risk.Obturacyjny bezdech senny (OBS) jest szeroko rozpowszechnionym schorzeniem. Jego związek z chorobami układu krążenia, a w szczególności jego wpływ na zwiększoną częstość występowania nadciśnienia tętniczego, został dobrze udokumentowany. Wyniki badań z ostatnich lat w grupie chorych z bezdechem sennym jednoznacznie sugerują, że pierwotnie przypisywany wpływowi nadciśnienia tętniczego rozwój poważnych powikłań narządowych, tj. zawału serca, zaburzeń rytmu serca, a przede wszystkim udaru mózgu, może w dużym stopniu wynikać ze współwystępującego, nieleczonego bezdechu. Jednocześnie istnieją liczne doniesienia wskazujące, że skuteczna terapia OBS obniża ryzyko wystąpienia wymienionych wyżej powikłań

Chronic Intermittent Hypoxia Exposure Promotes Multiple Myeloma Development in Black/6 Mice

Multiple myeloma (MM) is an incurable malignancy of bone marrow plasma B cells and is associated with obesity. The mechanisms by which obesity contributes to MM risk remains unclear, however, we speculate the linking factor to be sleep apnea which we simulated by chronic intermittent hypoxia (CIH). 5TGM1 cells are a murine MM cell line derived from the KaLwRij strain that fail to routinely engraft in Black6 mice. To test the hypothesis that chronic intermittent hypoxia (CIH) promotes the development of MM, we exposed MM-resistant C57BL/6 mice to 10h/day of CIH during the light cycle (AHI=10-12/h) for 7 days, or static 21% oxygen as a control. On day 7, mice were injected with 1x106 GFP-labelled malignant mouse plasma cells (5TGM1) and the CIH was continued for an additional 28 days. 67% of the CIH mice developed MM, evidenced by paralysis, bone lesions in the spine, and plasmacytomas in the femur. It was also tested if the CIH effected the cells intrinsically. We hypothesized that CIH would promote the proliferation of 5TGM1 cells in culture. Two groups of 5TGM1 cells were plated in 18 gas permeable wells at a concentration of 500,000 cells/mL. One plate was placed in a plexiglass environmental control cabinet and the other plate was placed in a normoxia incubator. The incubator was maintained at 21% O2 as a control. The environmental control cabinet, however, was maintained at an O2 level that decreased to 10% for 90s, every five minutes, for 10 hours per day. The control plate showed normal signs of proliferation. On the other hand, the plate maintained in CIH conditions showed rapid cell death as early as Day 2 of the experiment. These results suggest that the CIH conditions do not cause growth and proliferation of the 5TGM1 cell line. Therefore, we speculate that CIH may exert its MM-promoting effects on the bone marrow stromal environment and not directly on the tumor. Future work in our laboratory will investigate the role of CIH in transforming the bone marrow microenvironment to allow for tumor cell engraftment

Sleep medicine and dentistry

Many health care professionals and patients are unclear of the role that dentists may play in the management of Obstructive Sleep Apnoea-Hypopnoea Syndrome (OSAHS.) The dentists’ role is primarily in the construction of appliances for OSAHS but in the United States of America some dentists have practices limited to “Sleep dentistry”. However, in the United Kingdom there is limited training for dentists in this field. This thesis aims to review the relevant literature that pertains to OSAHS and dentistry and then, through three studies, to look at the past, present and future involvement of dentists in OSAHS. Assessing outcome is clearly important and this thesis firstly presents patient-based findings of the long term success of mandibular advancement appliances. Secondly, the experience and views of dentists and sleep specialists, assessed by questionnaire, is presented. Finally, a prospective study of a promising screening tool (the Kushida Index) for the diagnosis of sleep apnoea is carried out