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 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Excessive daytime somnolence is the main symptom of the obstructive sleep apnea syndrome (OSAS). Repetitive upper airway obstructions during sleep are followed by arousals and consequent sleep fragmentation. Furthermore, obstructive apneas or hypopneas and arousals are accompanied by fluctuations of blood pressure and heart rate. Several recent studies have found OSAS to be an independent risk factor for arterial hypertension and cardiovascular diseases.
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PMID:[Sleep apnea syndrome, arterial hypertension and cardiovascular risks]. 853 75

Obstructive sleep apnea is a breathing disorder characterized by repeated collapse of the upper airway during sleep, with cessation of breathing. Four percent of middle-aged men and 2 percent of middle-aged women meet minimal criteria for the sleep apnea syndrome. Risk factors include loud, chronic snoring, obesity (especially nuchal), hypertension, excessive daytime sleepiness, and an increased tendency for automobile and work-related accidents. Cardiovascular comorbidity and complications include systemic hypertension, arrhythmias and possibly myocardial ischemia and myocardial infarction in patients with coronary artery disease. Diagnosis is confirmed by a sleep study; currently, polysomnography is the optimum test. Treatment options range from behavioral therapy alone for mild cases to a combination of behavioral approaches and continuous positive airway pressure and/or surgery for moderate and severe cases. Continuous positive airway pressure is the most effective noninvasive treatment. Primary care physicians play a key role in the identification, management and follow-up of patients with sleep apnea.
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PMID:Sleep apnea: is your patient at risk? National Heart, Lung, and Blood Institute Working Group on Sleep Apnea. 854 58

Obstructive sleep apnea syndrome (OSAS) is the most important form of sleep-related breathing disorders due to its high prevalence and its potential for developing cardiovascular diseases. The increased morbidity of these patients is explained by the coincidence with cardiovascular diseases, and the increased mortality of untreated patients is due to cardiovascular complications, which depend on the degree of the breathing disorder. Heavy snoring, as a partial obstruction of the upper airways, and OSAS are independent risk factors for the development of cardiovascular diseases and stroke. Causal associations exist between acute hemodynamic changes, pressure and volume load, changes in the humoral and the central nervous system, and blood gas alterations during the obstructive apnea and the long-term condition due to OSAS. Obstructive apnea can be divided into an early phase, a late phase, and a phase of the postapneic hyperventilation with respect to hemodynamic changes, blood gas alterations, and the autonomic nervous system. The most striking changes in these parameters are seen at the end of apnea and in the first resumption of breathing, with an increase in systemic and pulmonary blood pressure, decrease in stroke volume, and a distinct change in heart rate. Manifestation of systemic hypertension even in the awake state is promoted by changes in the volume system, with activation of neurohumoral changes and by a resetting of baro- and chemoreceptors. Similar mechanisms are discussed in the development of pulmonary hypertension. In this circumstance the role of hypoxemia as a causal factor for pulmonary hypertension or as a consequence due to structural changes of the pulmonary vessels is controversial. OSAS is frequent in patients with coronary heart disease and these patients must be classified as a particular risk group because of apnea-associated silent myocardial ischemia and electric instability of the myocardium. The occurrence of arrhythmia in patients with OSAS is closely related to the apnea and hyperventilation events and depends on the sympathovagal balance. Early diagnosis and suitable therapy of patients at risk not only abolishes the sleep-related breathing disorder but also improves long-term outcome.
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PMID:[Sleep apnea and cardiovascular risk]. 857 38

Obstructive sleep apnea (OSA) is a common disorder associated with systemic hypertension, myocardial infarction, stroke, and premature death. Elevated sympathetic tone has been documented previously in OSA and may contribute to the cardiovascular risk. As OSA therapy appears to reduce mortality, we wondered if decreased apnea activity would attenuate the sympathetic hyperactivity of untreated patients. Muscle sympathetic nerve activity (MSNA) was measured during wakefulness via peroneal microneurography in seven patients with documented OSA before and at least 1 mo after compliance-monitored nasal continuous positive airway pressure (CPAP) therapy. Before institution of CPAP therapy, MSNA was high in all patients and decreased after CPAP therapy (baseline versus CPAP: 69.4 +/- 15.3 versus 53.9 +/- 10.5 bursts/min, mean +/- SD; p<0.01). However, the decrease in MSNA was limited to the four patients with the greatest nightly use of CPAP (> or = 4.5 h/night), whereas it remained unchanged in the three patients who were less compliant. There was a direct linear correlation between the decrease in MSNA (bursts/min) and the average hours of CPAP use per night (r = 0.87, p = 0.01). We conclude that in patients with OSA effective reduction in apnea activity with CPAP therapy diminishes the high sympathetic tone present during resting wakefulness.
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PMID:Influence of treatment on muscle sympathetic nerve activity in sleep apnea. 861 63

Obstructive sleep apnea (OSA) is a common condition with serious health and social consequences for millions of people. If untreated, it has significant effects on mortality, particularly by contributing to the rate of hypertension, stroke, and cardiac pathology. Standard therapy involves the use of a nasal continuous positive airway pressure device during sleep. This keeps the upper airway from collapsing, avoiding the cause of apneas and hypopneas. The inconvenience and side effects of the device make compliance with its use less than ideal. There are several surgical techniques that have been developed to correct OSA. These techniques have had variable success rates and are accompanied by some morbidity and mortality. Intraoral devices that position the mandible forward show promise for increasing the hypopharyngeal airway. A technique for physiologically determining an effective jaw relationship is described, as is a design for a device that maximizes nighttime retention. Radiographic analyses in the upright and supine positions are used to determine adequate airway improvement. The intraoral device can be used as a diagnostic tool to select patients who will most likely benefit from surgery.
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PMID:Obstructive sleep apnea: a mandibular positioning device for treatment and diagnosis of an obstruction site. 862 Mar 90

We have investigated pulmonary hemodynamics in a large series of consecutive, unselected patients with obstructive sleep apnea syndrome (OSAS). The aims of this study were to evaluate the frequency of pulmonary artery hypertension (PH) in OSAS and to analyze, as far as possible, its mechanisms. Two hundred twenty patients were included on the basis of a polysomnographic diagnosis of OSAS (apnea+hypopnea index > 20). PH, defined by a resting mean pulmonary artery mean pressure (PAP) of at least 20 mm Hg, was observed in 37 of 220 patients (17%). Patients with PH differed from the others with regard to pulmonary volumes (vital capacity [VC], FEV1) and the FEV1/VC ratio that were significantly lower (p < 0.001); PaO2 (64.4 +/- 9.3 vs 74.7 +/- 10.1 mm Hg; p < 0.001); PaCO2 (43.8 +/- 5.4 vs 37.6 +/- 3.9 mm Hg; p < 0.001), apnea+hypopnea index (100 +/- 33 vs 74 +/- 32; p < 0.001), and mean nocturnal arterial oxygen saturation (SaO2) (88 +/- 6% vs 94 +/- 2%; p < 0.001). Patients with PH were also more overweight (p < 0.001). Multiple regression analysis showed that 50% of the variance of PAP could be predicted by an equation including PaCO2 (accounting for 32% of the variance), FEV1 (12%), airway resistance (4%), and mean nocturnal SaO2 (2%). In conclusion, PH is observed, in agreement with previous studies, in less than 20% of OSAS patients. PH is strongly linked to the presence of an obstructive (rather than restrictive) ventilatory pattern, hypoxemia, and hypercapnia, and is generally accounted for by an associated obstructive airways disease. In this regard, the severity of OSAS plays only a minor role.
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PMID:Pulmonary hemodynamics in the obstructive sleep apnea syndrome. Results in 220 consecutive patients. 899 33

Data concerning the occurrence of chronic-obstructive pulmonary disease (COPD) in patients with obstructive sleep apnea syndrome (OSAS) vary between 11 and 20% due to the underlying definition of COPD. We investigated the frequency of COPD in 202 patients with OSAS. The obstructive pattern was defined by bodyplethysmography (Rt > 0.35 kPa x 1(-1) x s(-1)), flow-volume-curve (MEF50 < 50% pred.), Tiffeneau-index (FEV1/IVC < 70% pred.) and anamnesis (cough and/or sputum). Prevalence of COPD in our 202 patients with OSAS was 16.3%. Patients with OSAS and COPD had a higher body-mass-index (BMI), lower PaO2 and spent more time in an oxygen saturation < or = 90% in relation to total recording time (t90). Polysomnographically there was no difference between the two groups with regard to the ventilatory parameters apnea-index (AI) and apnea-hypopnea-index (AHI). As there is a high risk of developing hypercapnia, pulmonary arterial hypertension and cor pulmonale in patients with OSAS and COPD there is need for early diagnosis of the combination of both diseases.
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PMID:[Incidence of chronic obstructive respiratory tract disease in patients with obstructive sleep apnea]. 868 3

The main acute cardiovascular effects of obstructive sleep apnea syndrome (OSAS) are elevation of blood pressure and reflectory bradycardia, which are followed by an abrupt tachycardia on resumption of breathing. This haemodynamic instability is related to hypoxemia and arousal, and may lead to increased risk from cardiac arrhythmias and sudden cardiac death, as well as to the development of chronic arterial hypertension, in these patients. The aim of this study was to apply frequency domain analysis of heart rate variability (HRV) measured from continuous electrocardiogram (ECG) recordings to evaluate how cardiac autonomic function, and especially cardiac sympathovagal tone, changes during sleep apnea episodes. We identified 41 apneas leading to more than 4%-unit arterial oxygen desaturation in 12 patients (11 men, 1 woman (correction for women), age range 27-67 years). Frequency domain analysis of HRV was performed from ECG recordings using 4 min epochs starting 20 min before apnea began and lasting 20 min after the beginning of apnea. The mean (+/-SEM) fall in oxygen saturation during the apnea was 6.8 +/- 0.6%-units. While high frequency band (HF, reflects cardiac vagal activity) remained unchanged, low frequency band (LF, mainly sympathetic activity) showed a constant increase, leading to significant change in the sympathovagal balance (LF/HF ratio). In conclusion, concordantly with previous peripheral sympathetic-nerve recordings, frequency domain analysis of HRV is able to detect sympathetic activation during sleep apnea episodes, leading to marked change in the sympathovagal balance.
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PMID:Cardiac sympathovagal balance during sleep apnea episodes. 873 9

Obstructive sleep apnoea syndrome is due to pharyngeal obstruction of inspiratory airflow with preservation of thoraco-abdominal respiratory movements. This disease has been described for about thirty years, but is now the subject of growing interest. According to the increasingly abundant literature on this subject, OSAS is associated with essentially cardiovascular morbidity and mortality (systemic hypertension, pulmonary hypertension, heart failure, coronary heart disease, arrhythmias, cerebral vascular accidents and sudden death). The pathophysiology of its underlying mechanisms and its complications is complex and multifactorial. The diagnosis of this syndrome should be suspected on clinical interview (snoring, excessive daytime drowsiness, and apnoea during sleep) and is confirmed by polysomnography. Nasal continuous positive pressure with elimination of aggravating factors is the reference treatment in 1994. The diagnosis and management of this syndrome requires a multidisciplinary approach with collaboration between general practitioners, neurologists, maxillofacial/ENT surgeons, cardiologists and respiratory physicians.
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PMID:[Obstructive sleep apnea syndrome and cardiovascular diseases]. 874 61

We studied 176 patients with habitual snoring (HS) and obstructive sleep apnea (OSA) to find out whether Japanese patients with OSA differ from those in western countries. The prevalence and pathophysiology of hypertension may substantially differ between OSA patients in Japan and in western countries: body mass index may be more closely associated with hypertension in western patients. No statistical relationship was found between obesity and hypertension in Japanese patients. Although the reason is unknown, thinner body builds in Japanese patients could account for this difference. However, if Japanese patients complain of severe obesity or excessive daytime sleepiness, or both, and have a saw-tooth sign in the flow-volume curve or hypertension, or both, a polysomuography should be indicated.
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PMID:[Sign and symptoms in Japanese patients with obstructive sleep apnea: present status and problems]. 875 81


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