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Query: UMLS:C0037315 (sleep apnea)
 8,000 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sleep-disordered breathing, broadly characterized by obstructive sleep apnea (OSA) and central sleep apnea (CSA), is an increasingly recognized public health burden. OSA, consisting of apneas or hypopneas associated with respiratory efforts in the face of upper airway narrowing or collapse, is a common disorder that can be effectively treated with continuous positive airway pressure (CPAP). OSA not only results in daytime sleepiness and impaired executive function, but also has been implicated as a possible cause of systemic disease, particularly of the cardiovascular system. CSA, which may coexist with OSA, has gained attention because of the association of Cheyne-Stokes respiration with an ever-increasing prevalence of heart failure in an aging population. This article reviews some of the extensive literature on pathophysiologic mechanisms as they may relate to the development of cardiac and vascular disease and examine the evidence suggesting OSA as a specific cause of certain cardiovascular conditions. Available evidence regarding the implications of CSA in the context of heart failure is discussed.
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PMID:Sleep-disordered breathing and cardiovascular risk. 1742 25

More than half of all patients with stable heart failure are affected by sleep apnea syndrome. The mechanism of apnea may be either obstructive, by collapse of the upper airways, or central with nocturnal Cheyne-Stokes respiration. Changes in intrathoracic pressure, awakening and hypoxemia all lead to an increase in left ventricular afterload and to sympathetic activation, which can aggravate heart failure and prognosis. Treatment with positive pressure ventilation improves symptoms as well as cardiac function and prognosis. Sleep respiratory disorders are underdiagnosed and undertreated in patients with stable heart failure. To improve management of sleep apnea, patients with stable heart failure should be screened with small outpatient oximeters.
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PMID:[Sleep apnea syndrome and heart failure]. 1744 35

Recurrent total or partial upper airway collapse occurring during sleep characterizes obstructive sleep apnea syndrome (OSAS). Although the disease is affecting more than 5% of the general population, it remains largely undiagnosed. The disease is associated with augmented cardiovascular risk, reduction in vigilance and attentional abilities, being responsible for traffic or occupational accidents. There is also glucose metabolism impairment likely to occur during OSA i.e. resistance to insulin and diabetes. Simplified tools are available in order to achieve the diagnosis either in the sleep laboratory environment or ambulatory. Nasal continuous positive airway pressure (CPAP) remains the reference treatment. CPAP acts as a pneumatic splint that maintains UA patency. CPAP efficiency is well demonstrated, both on sleepiness and cardiovascular outcomes. Oral appliance is an alternative to CPAP in sleep apnea syndrome, preferentially when moderate in non-obese subjects. Surgical treatment remains poorly efficient and is of limited use in OSA. Lastly, pharmacological developments are currently being evaluated regarding symptoms such as sleepiness or comorbidities.
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PMID:[Obstructive sleep apnea syndrome]. 1801 55

With the growing epidemic of obesity in an aging population, obstructive sleep apnea (OSA) is increasingly encountered in clinical practice. Given the acute cardiopulmonary stressors consequent to repetitive upper airway collapse, as well as evidence for cardiovascular homeostatic dysregulation in subjects with sleep apnea, there is ample biologic plausibility that OSA imparts increased cardiovascular risk, independent of comorbid disease. Indeed, observational studies have suggested strong associations with multiple disorders, such as systemic hypertension, heart failure, cardiac arrhythmias, and pulmonary hypertension. Further data in the form of longitudinal cohort studies and randomized controlled trials are accruing to add to the body of evidence. This review examines pathophysiologic mechanisms and explores current concepts regarding the impact of OSA and its treatment on selected clinical disease states.
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PMID:Obstructive sleep apnea, cardiovascular disease, and pulmonary hypertension. 1825 Feb 13

The upper airway of obstructive sleep apnoea patients is subjected to recurrent negative pressure swings promoting its collapse and reopening. The aim of the present study was to ascertain whether this mechanical stress induces upper airway inflammation in a rat model. The upper airway of Sprague-Dawley rats was subjected to a periodic pattern of recurrent negative (-40 cmH2O, 1 s) and positive (4 cmH2O, 2 s) pressures inducing collapse and reopening for 5 h. Rats that were instrumented but not subjected to negative pressure swings were used as controls. The gene expression of the pro-inflammatory biomarkers macrophage inflammatory protein (MIP)-2, tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta and P-selectin in the soft palate and larynx tissues was assessed by real-time PCR. A marked overexpression of MIP-2, TNF-alpha, IL-1beta and P-selectin (approximately 40-, 24-, 47- and 7-fold greater than controls, respectively) was observed in the larynx tissue; similar results were found in the soft palate tissue (approximately 14-, 7-, 35- and 11-fold greater than controls, respectively). Recurrent upper airway collapse and reopening mimicking those experienced by obstructive sleep apnoea patients triggered an early local inflammatory process. These results could explain the inflammation observed in the upper airway of obstructive sleep apnoea patients.
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PMID:Upper airway collapse and reopening induce inflammation in a sleep apnoea model. 1866 83

The present study measured hypotonic pharyngeal collapsibility in subjects not known to have obstructive sleep apnoea (OSA), and assessed the variables that affect collapsibility and the relationship with OSA. The critical value of positive end-expiratory pressure (P(crit)) was measured under the hypotonic condition of anaesthesia in 227 subjects who underwent elective surgery. The risk of OSA in this population was estimated using the Berlin questionnaire. The mean P(crit) for all subjects was positive (above atmospheric), ranging from 0.69 (95% confidence interval (CI) -7.39-8.77) to 4.0 (CI -4.82-12.82) cmH(2)O for subjects with low and high prevalence of OSA, respectively. P(crit) < or = -5 cmH(2)O was only found in 3.1% of the study subjects. In the general population, P(crit) was similar in males and females and correlated positively with increasing age, while a correlation with neck circumference was found only in males. P(crit )accounted for only 12.25% of the variability in OSA risk score. In conclusion, subjects with high critical value of positive end-expiratory pressure are at an increased risk for developing obstructive sleep apnoea. However, the human pharynx is prone to collapse and occludes in most people in the absence of neuromuscular support. Therefore, in most subjects, the level of neuromuscular activity may ultimately determine the occurrence of sleep apnoea.
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PMID:Collapsibility of the relaxed pharynx and risk of sleep apnoea. 1855 Jun 11

Even though the effects of surgery and anesthesia on sleep have not been completely defined yet, it is an irrefutable fact that the patients with sleep apnea could experience significant perioperative complications, in terms of common difficult airway problems, as well as prolonged emergence from anesthesia. Besides, there are strong evidences of correlation between sleep apnea and hypertension and other cardiovascular diseases. Preoperative questions about sleep, possible snoring, or excessive daytime sleepiness should become a routine part of preanesthesia evaluation, together with airway examination and thorough pulmonary and cardiovacular examination. However, the exact severity of the obstructive sleep apnea (OSA) could be precisely defined only by polysomnography. Every patient diagnosed with OSA, or with clinical suspicion of OSA, should be considered to have a difficult airway, until proven otherwise, and consequently has increased risk of anesthesia. The possible problems may arise during tracheal intubation, extubation, or with postoperative analgesia, since opioids increase the incidence of pharyngeal collapse. Whenever possible, regional anesthesia techniques should be used. On the other hand, by documenting every difficult airway management, difficult intubation or prolonged recovery, the anesthesiologists are in good position to effectively screen for OSA in population.
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PMID:[Obstructive sleep apnea and anesthesia]. 1859 65

Sleep apnea and hypopnea syndrome (SAHS) is a disorder characterized by intermittent and repetitive obstruction of the upper airway provoking pharyngeal collapse. It is characterized clinically by a triad of daytime hypersomnia, snoring and pauses in breathing during sleep that are normally reported by the partner. Polysomnography is the chosen method for diagnosing this pathology. Patients with this disorder tend to have the following dental and orofacial signs: a retrognathic jaw, a narrow palate, a wide neck, deviation of the nasal septum and relative macroglossia, among others. Dentists should be ready to evaluate the risk-benefit of certain dental treatment options for this public health problem. The treatment of this problem will depend on its severity, with one of the options being the Mandibular Advancement Device (MAD) that is used especially in the treatment of slight or moderate SAHS and in the treatment of snoring, with results that are occasionally very successful. The objective of this study is to carry out an up-to-date literature review of SAHS and to evaluate the role of the dentist when faced with this pathology.
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PMID:Sleep apnea and mandibular advancement device. Revision of the literature. 1875 97

1. Flow in single vascular conduits is reviewed, divided into distended and deflated vessels. 2. In distended vessels with pulsatile flow, wave propagation and reflection dominate the spatial and temporal distribution of pressure, determining the shape, size and relative timing of measured pressure waveforms, as well as the instantaneous pressure gradient everywhere. Considerable research has been devoted to accessing the information on pathological vascular malformations contained in reflected waves. Slow waves of contraction of vessel wall muscle, responsible for transport of oesophageal, ureteral and gut contents, have also been modelled. 3. The pressure gradient in a vessel drives the flow. Flow rate can be predicted both analytically and numerically, but analytical theory is limited to idealized geometry. The complex geometry of biological system conduits necessitates computation instead. Initially limited to rigid boundaries, numerical methods now include fluid-structure interaction and can simultaneously model solute transport, thus predicting accurately the environment of the mechanosensors and chemosensors at vessel surfaces. 4. Deflated vessels display all phenomena found in distended vessels, but have additional unique behaviours, especially flow rate limitation and flow-induced oscillation. Flow rate limitation is widespread in the human body and has particular diagnostic importance in respiratory investigation. Because of their liquid lining, the pulmonary airways are also characterized by important two-phase flows, where surface tension phenomena create flows and determine the patency and state of collapse of conduits. 5. Apart from the vital example of phonation, sustained self-excited oscillation is largely avoided in the human body. Where it occurs in snoring, it is implicated in the pathological condition of sleep apnoea.
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PMID:Fluid flow in distensible vessels. 1878 81

The objective of the study is to assess the correlation between outpatient department (OPD) assessment and sleep nasendoscopy (SNE) in treatment planning for sleep related breathing disorders. The study design includes a blinded, cohort study comparing the treatment prediction based on OPD clinical evaluation with SNE in consecutive, adult patients by a single clinician with a specialist interest in snoring related disorders. Patients with moderate to severe obstructive sleep apnoea and those who had undergone previous treatment were excluded. The study was conducted in Royal National Throat, Nose and Ear Hospital, London and Queen's Hospital, Romford. Ninety-four patients were recruited as participants for the study. The main outcome measures include site of obstruction and treatment planning. The results show no significant correlation between the two groups with SNE recommending less surgical intervention and a choice of surgical and non-surgical management in greater number of patients. In conclusion, even in experienced hands, clinical prediction is significantly modified by SNE findings. The addition of SNE to the diagnostic pathway, to assess the three-dimensional dynamic anatomy of the upper airway, provides a valuable adjunct to the OPD assessment of upper airway collapse. This affords the clinician a greater accuracy of diagnosis and the patient a more focussed management strategy with increased choice of modality of treatment.
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PMID:Is sleep nasendoscopy a valuable adjunct to clinical examination in the evaluation of upper airway obstruction? 1894 65


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