Coupling between respiratory and sympathetic activities as a novel mechanism underpinning neurogenic hypertension

Enhanced sympathetic outflow to the heart and resistance vessels greatly contributes to the onset and maintenance of neurogenic hypertension. There is a consensus that the development of hypertension (clinical and experimental) is associated with an impairment of sympathetic reflex control by arterial baroreceptors. More recently, chronic peripheral chemoreflex activation, as observed in obstructive sleep apnea, has been proposed as another important risk factor for hypertension. In this review, we present and discuss recent experimental evidence showing that changes in the respiratory pattern, elicited by chronic intermittent hypoxia, play a key role in increasing sympathetic activity and arterial pressure in rats. This concept parallels results observed in other models of neurogenic hypertension, such as spontaneously hypertensive rats and rats with angiotensin II–salt-induced hypertension, pointing out alterations in the central coupling of respiratory and sympathetic activities as a novel mechanism underlying the development of neurogenic hypertension.

Relaxamento progressivo, stress, enfrentamento e qualidade de vida em pessoas com apneia obstrutiva do sono

Pós-graduação em Psicologia do Desenvolvimento e Aprendizagem - FC

Qualidade do sono em pacientes com síndrome do túnel do carpo

Pós-graduação em Bases Gerais da Cirurgia - FMB

Ensaio clínico randomizado duplo-cego do perfil inflamatório e do nível de estresse oxidativo em indivíduos com diagnóstico polissonográfico de SAOS antes e após o uso de CPAP

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Chronic intermittent hypoxia alters glutamatergic control of sympathetic and respiratory activities in the commissural NTS of rats

Costa-Silva JH, Zoccal DB, Machado BH. Chronic intermittent hypoxia alters glutamatergic control of sympathetic and respiratory activities in the commissural NTS of rats. Am J Physiol Regul Integr Comp Physiol 302: R785-R793, 2012. First published December 28, 2011; doi:10.1152/ajpregu.00363.2011.-Sympathetic overactivity and altered respiratory control are commonly observed after chronic intermittent hypoxia (CIH) exposure. However, the central mechanisms underlying such neurovegetative dysfunctions remain unclear. Herein, we hypothesized that CIH (6% O-2 every 9 min, 8 h/day, 10 days) in juvenile rats alters glutamatergic transmission in the commissural nucleus tractus solitarius (cNTS), a pivotal site for integration of peripheral chemoreceptor inputs. Using an in situ working heart-brain stem preparation, we found that L-glutamate microinjections (1, 3, and 10 mM) into the cNTS of control rats (n = 8) evoked increases in thoracic sympathetic nerve (tSN) and central vagus nerve (cVN) activities combined with inhibition of phrenic nerve (PN) activity. Besides, the ionotropic glutamatergic receptor antagonism with kynurenic acid (KYN; 250 mM) in the cNTS of control group (n = 7) increased PN burst duration and frequency. In the CIH group (n = 10), the magnitude of L-glutamate-induced cVN excitation was smaller, and the PN inhibitory response was blunted (P < 0.05). In addition, KYN microinjections into the cNTS of CIH rats (n = 9) did not alter PN burst duration and produced smaller increases in its frequency compared with controls. Moreover, KYN microinjections into the cNTS attenuated the sympathoexcitatory response to peripheral chemoreflex activation in control but not in CIH rats (P < 0.05). These functional CIH-induced alterations were accompanied by a significant 10% increase of N-methyl-D-aspartate receptor 1 (NMDAR1) and glutamate receptor 2/3 (GluR2/3) receptor subunit density in the cNTS (n = 3-8, P < 0.05), evaluated by Western blot analysis. These data indicate that glutamatergic transmission is altered in the cNTS of CIH rats and may contribute to the sympathetic and respiratory changes observed in this experimental model.

Adaptive servo-ventilation as treatment of persistent central sleep apnea in post-acute ischemic stroke patients.

BACKGROUND Adaptive servo-ventilation (ASV) is a well-established treatment of central sleep apnea (CSA) related to congestive heart failure (CHF). Few studies have evaluated the effectiveness and adherence in patients with CSA of other etiologies, and even less is known about treatment of CSA in patients of post ischemic stroke. METHODS A single-centre retrospective analysis of ASV treatment for CSA in post-acute ischemic stroke patients without concomitant CHF was performed. Demographics, clinical data, sleep studies, ventilator settings, and adherence data were evaluated. RESULTS Out of 154 patients on ASV, 15 patients had CSA related to ischemic stroke and were started on ASV a median of 11 months after the acute cerebrovascular event. Thirteen out of the 15 patients were initially treated with continuous positive airway pressure (11/15) and bilevel positive airway pressure (2/15) therapy with unsatisfactory control of CSA. ASV significantly improved AHI (46.7 ± 24.3 vs 8.5 ± 12/h, P = 0.001) and reduced ESS (8.7 ± 5.7 vs 5.6 ± 2.5, P = 0.08) with a mean nightly use of ASV of 5.4 ± 2.4 h at 3 months after the initiation of treatment. Results were maintained at 6 months. CONCLUSION ASV was well tolerated and clinically effective in this group of patients with persistent CSA after ischemic stroke.

[Klinik und Diagnose von Hypogonadismus und Andropause]

Diagnosis and therapy of male hypogonadism is still a challenge because of the unspecific clinical signs and symptoms. The clinical presentation of a androgen deficiency is age-related. In the adult men, one can often observe fatigue, decrease in physical capacity, loss of libido and erectile dysfunction. At the physical examination, genitalia have always to be assessed in search of a testes/penis atrophy. Two fasting measurements of total testosterone concentrations by a reliable assay are needed to confirm the diagnosis. By assessing gonadotropines the origin of hypogonadism can be determined (central/secondary or peripheral/primary). Exogenous administration of androgens should be considered in young, sportive, healthy and muscular males. Patients with metabolic syndrome should only be screened for hypogonadism in the presence of suggestive symptoms. Prostate disease, hematocrit higher than 50 %, uncontrolled heart failure and severe obstructive sleep apnea are contraindications of a testosterone replacement therapy. Patients with metabolic-syndrome-associated low testosterone levels should firstly benefit from a lifestyle intervention that can normalize clinical and biochemical hypogonadism. So far, there is no clear evidence for a possible benefit of testosterone therapy in patients with the metabolic syndrome. Similarly, in patients with PADAM (partial androgen deficiency of the aging male) testosterone therapy is not established or recommended.

Analyzing training dependencies and posterior fusion in discriminant classification of apnoea patients based on sustained and connected speech

We present a novel approach using both sustained vowels and connected speech, to detect obstructive sleep apnea (OSA) cases within a homogeneous group of speakers. The proposed scheme is based on state-of-the-art GMM-based classifiers, and acknowledges specifically the way in which acoustic models are trained on standard databases, as well as the complexity of the resulting models and their adaptation to specific data. Our experimental database contains a suitable number of utterances and sustained speech from healthy (i.e control) and OSA Spanish speakers. Finally, a 25.1% relative reduction in classification error is achieved when fusing continuous and sustained speech classifiers. Index Terms: obstructive sleep apnea (OSA), gaussian mixture models (GMMs), background model (BM), classifier fusion.

Which diagnostic findings in disorders with excessive daytime sleepiness are really helpful? A retrospective study.

Due to extensive clinical and electrophysiological overlaps, the correct diagnosis of disorders with excessive daytime sleepiness is often challenging. The aim of this study was to provide diagnostic measures that help discriminating such disorders, and to identify parameters, which don't. In this single-center study, we retrospectively identified consecutive treatment-naïve patients who suffered from excessive daytime sleepiness, and analyzed clinical and electrophysiological measures in those patients in whom a doubtless final diagnosis could be made. Of 588 patients, 287 reported subjective excessive daytime sleepiness. Obstructive sleep apnea is the only disorder that could be identified by polysomnography alone. The diagnosis of insufficient sleep syndrome relies on actigraphy as patients underestimate their sleep need and the disorder shares several clinical and electrophysiological properties with both narcolepsy type 1 and idiopathic hypersomnia. Sleep stage sequencing on MSLT appears helpful to discriminate between insufficient sleep syndrome and narcolepsy. Sleep inertia is a strong indicator for idiopathic hypersomnia. There are no distinctive electrophysiological findings for the diagnosis of restless legs syndrome. Altogether, EDS disorders are common in neurological sleep laboratories, but usually cannot be diagnosed based on PSG and MSLT findings alone. The diagnostic value of actigraphy recordings can hardly be overestimated.

Snoring and its association with asthma in Indigenous children living in the Torres Strait and Northern Peninsula Area

Objective: Respiratory health of Indigenous and minority ethnic groups in affluent countries is poorer than their non-minority counterparts and sleep disorders are no exception. In children, obstructive sleep apnoea has the potential to result in serious long-term consequences. In 1999, we studied 1650 children and adolescents living in the Torres Strait and the Northern Peninsula Area, Australia. Here we report prevalence of snoring in these communities and relate its association with asthma symptoms. Methods: A population-based cross-sectional study was conducted in the Torres Strait region. Five indigenous communities were randomly selected and information was collected using a structured face-to-face interview based on a standardized questionnaire. There was a 98% response rate, and 1650 children, 0-17 years of age, were included in the study. Results: Overall, the prevalence of snoring was 14.2% (95% CI 12.5-15.9); 3.6% (95% CI 2.7-4.6) reported snorting, and 6% (95% CI 4.9-7.2) reported restless sleep. The prevalence of snoring was significantly higher among males (17.1% for males and 10.8 for females, P = 0.005). Children were five times more likely to have experienced snoring and snorting if they reported wheezing in the last 12 months. Conclusion: We conclude that the prevalence of symptoms suggestive of obstructive sleep problems is relatively high in children of this region. This highlights the need for awareness among the community patients and physicians about the problem of obstructive sleep-disordered breathing, especially in children with asthma, and for the need for further studies to measure prevalence of sleep breathing disorders among Indigenous Australians.

Use of pulse transit time to distinguish respiratory events from tidal breathing in sleeping children

Study objectives: Currently, esophageal pressure monitoring is the "gold standard" measure for inspiratory efforts, hut its invasive nature necessitates a better tolerated and noninvasive method to be used on children. Pulse transit time (PTT) has demonstrated its potential as a noninvasive surrogate marker for inspiratory efforts. The principle velocity determinant of PTT is the change in stiffness of the arterial wall and is inversely correlated to BP. Moreover, PTT has been shown to identify changes in inspiratory effort via the BP fluctuations induced by negative pleural pressure swings. In this study, the capability of PTT to classify respiratory, events during sleep as either central or obstructive in nature was investigated. Setting and participants: PTT measure was used in adjunct to routine overnight polysomnographic studies performed on 33 children (26 boys and 7 girls; mean +/- SD age, 6.7 +/- 3.9 years). The accuracy of PTT measurements was then evaluated against scored corresponding respiratory events in the polysomnography recordings. Results: Three hundred thirty-four valid respiratory events occurred and were analyzed. One hundred twelve obstructive events (OEs) showed a decrease in mean PTT over a 10-sample window that had a probability of being correctly ranked below the baseline PTT during tidal breathing of 0.92 (p < 0.005); 222 central events (CEs) showed a decrease in the variance of PTT over a 10-sample window that had a probability of being ranked below the baseline PTT of 0.94 (p < 0.005). This indicates that, at a sensitivity of 0.90, OEs can be detected with a specificity of 0.82 and CEs can be detected with a specificity of 0.80. Conclusions: PTT is able to categorize CEs and OEs accordingly in the absence of motion artifacts, including hypopneas. Hence, PTT shows promise to differentiate respiratory, events accordingly and can be an important diagnostic tool in pediatric respiratory sleep studies.< 0.005); 222 central events (CEs) showed a decrease in the variance of PTT over a 10-sample window that had a probability of being ranked below the baseline PTT of 0.94 (p < 0.005). This indicates that, at a sensitivity of 0.90, OEs can be detected with a specificity of 0.82 and CEs can be detected with a specificity of 0.80. Conclusions: PTT is able to categorize CEs and OEs accordingly in the absence of motion artifacts, including hypopneas. Hence, PTT shows promise to differentiate respiratory, events accordingly and can be an important diagnostic tool in pediatric respiratory sleep studies.');"

Pitch jump probability measures for the analysis of snoring sounds in apnea

Obstructive sleep apnea (OSA) is a highly prevalent disease in which upper airways are collapsed during sleep, leading to serious consequences. The gold standard of diagnosis, called polysomnography (PSG), requires a full-night hospital stay connected to over ten channels of measurements requiring physical contact with sensors. PSG is inconvenient, expensive and unsuited for community screening. Snoring is the earliest symptom of OSA, but its potential in clinical diagnosis is not fully recognized yet. Diagnostic systems intent on using snore-related sounds (SRS) face the tough problem of how to define a snore. In this paper, we present a working definition of a snore, and propose algorithms to segment SRS into classes of pure breathing, silence and voiced/unvoiced snores. We propose a novel feature termed the 'intra-snore-pitch-jump' (ISPJ) to diagnose OSA. Working on clinical data, we show that ISPJ delivers OSA detection sensitivities of 86-100% while holding specificity at 50-80%. These numbers indicate that snore sounds and the ISPJ have the potential to be good candidates for a take-home device for OSA screening. Snore sounds have the significant advantage in that they can be conveniently acquired with low-cost non-contact equipment. The segmentation results presented in this paper have been derived using data from eight patients as the training set and another eight patients as the testing set. ISPJ-based OSA detection results have been derived using training data from 16 subjects and testing data from 29 subjects.

Differentiating responses to obstructive sleep apnoea using pulse transit time

Conventional overnight polysomnography (PSG) used to determine the respiratory behaviour during sleep can be a complex and expensive procedure. Pulse transit time analysis (PTT) has shown potential to detect obstructive apnoeic and hypopnoeic events in adults. This study was undertaken to determine the potential of PTT to differentiate responses to upper airway obstruction. 103 obstructive respiratory events occurred in PSG studies performed on 11 children (10 male and 1 female, mean age 7.5years). PTT measurements were evaluated against the corresponding PSG results pre-scored by 2 blinded observers. Broadly, there were 2 types of responses. They can be either short period of rapid PTT decreases (Type 1) or prolonged but gradual PTT decreases (Type 2). Type 1 obstructive events showed a mean change of 51.77% (p

A Ortodontia e aparelhos intra orais no tratamento da SAHOS (Sindrome da Apneia e Hipopneia Obstrutiva do Sono)

A síndrome da apneia e hipopneia obstrutiva do sono (SAHOS) é uma patologia que atinge cerca de 4% da população adulta, é uma doença crónica, progressiva, com alta morbilidade e mortalidade. A apneia do sono e o ronco têm despertado a atenção da área da saúde devido às inúmeras comorbilidades associadas. Esta síndrome é caracterizada por obstrução parcial ou total das vias aéreas superiores durante o sono e manifesta-se como uma redução (hipopneia) ou cessação (apneia) do fluxo aéreo. A queixa habitual dos pacientes além dos problemas sociais como ronco e a hipersonolência diurna, são a preocupação com outros quadros que esta patologia pode desencadear, como insuficiência cardíaca e hipertensão pulmonar. O tratamento da apneia obstrutiva do sono é multidisciplinar e indispensável, podendo ser realizado de diversas formas, tanto conservadoras como cirúrgicas, dependendo de inúmeros fatores como a gravidade da doença, as alterações anatómicas das vias aéreas superiores, idade e condições sistémicas do paciente. Os aparelhos intra orais têm sido usados durante anos, no tratamento da SAHOS como controle da obstrução das vias aéreas superiores. A terapia com aparelhos intraorais é simples e reversível. O sucesso do tratamento com aparelhos intra orais para o ronco e SAHOS leve e moderada é comprovado pela grande maioria dos estudos. A facilidade de uso, manutenção e conforto quando comparados a outros tratamentos faz com que os aparelhos intrabucais sejam considerados de fácil aceitação pelos pacientes. Através de uma revisão de literatura discutiu-se o uso de aparelhos intrabucais para o tratamento dessa patologia, destacando a eficácia e as limitações dessa terapia, os principais sintomas clínicos, os principais efeitos colaterais oclusais, o grau de colaboração e o índice de satisfação dos pacientes. Foi possível concluir que aparelhos intrabucais de avanço mandibular estão amplamente indicados para o tratamento do ronco e da SAHOS como terapia principal, ou alternativa naqueles pacientes que não podem suportar a terapia da pressão positiva das vias aéreas e que para o sucesso do tratamento é fundamental uma equipe multidisciplinar, incluindo um Médico Dentista e a colaboração do paciente.