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 28,634 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recent studies have shown excitatory effects of serotonin on upper airway motoneurons. This excitatory effect is normally present and arises from cells in the caudal raphe nuclei. The firing of these serotonergic neurons is reduced during sleep. To determine the importance of serotonin in the maintenance of patient airways and normal respiration in waking in obstructive sleep apnea, we studied the effects of two serotonin antagonists on upper airway dilator muscle activity, diaphragm activity, Sao2, and upper airway cross-sectional area in an animal model of sleep-disordered breathing, the English bulldog. Systemic administration of both antagonists resulted in significant reductions in the peak amplitudes of upper airway muscle respiratory bursts (range, 39 to 62% suppression; p < 0.05). Lesser reductions in diaphragm activity were noted (range, 10 to 33% suppression; p < 0.05). Oxyhemoglobin saturations also fell (p < 0.05), coinciding with suppressions in upper airway muscle activity. With reductions in dilator muscle activity, upper airway cross-sectional areas, as measured with cine CT, showed significant inspiratory collapse. These results support the hypothesis that serotonin is important in the maintenance of patent upper airways in obstructive sleep apnea.
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PMID:The effects of serotonin antagonists in an animal model of sleep-disordered breathing. 856 32

Obstructive sleep apnea (OSA) occurs when airflow ceases because of pharyngeal wall collapse in sleep. Repeated apneic events results in the development of a pathological condition called OSA syndrome. We describe the methodology and design of a prosthetic device, named automatic positive airway pressure (APAP), for treatment of this syndrome. APAP applies a stream of air via a nasal mask at an initial pressure selected by the patient. By sensing specific pressure characteristics of air flow immediately preceding pharyngeal wall collapse, the APAP device automatically raises the applied pressure to maintain a patent upper airway and thus prevent apnea. Conversely, when such conditions are absent, pressure is lowered step wise until a preselected minimum pressure is reached. Performance evaluation of the APAP system in five OSA patients and five normal (asymptomatic for sleep apnea) subjects revealed that it effectively treated OSA syndrome. It lowered the apnea-hypopnea index without disturbing sleep and resulted in a lower mean airway pressure compared to the traditional continuous positive airway pressure (CPAP) therapy. The results also show that the pressure needed to prevent OSA varied significantly throughout the night. For OSA syndrome patients, this pressure ranged from 3 to 18 cm H2O. The mean airway pressure for these patients had a sample average of 6.80 cm H2O and a standard deviation of 3.17 cm H2O. In normal subjects, the device did not raise pressure except in response to Pharyngeal Wall Vibration events.
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PMID:Automatic control of airway pressure for treatment of obstructive sleep apnea. 858 18

Obstructive sleep apnoea is a chronic condition characterized by repetitive episodes of upper airway collapse during sleep, leading to sleep fragmentation. The management of sleep apnoea consists of general and specific measures. General measures should include weight loss in overweight patients; avoidance of alcohol during the evening hours; avoidance of any hypnotic drug. Specific measures may range from simple position training in patients with positional sleep apnoea (sleep apnoea appearing only when lying on the back) of slight severity; to oral appliances with the aim of creating a prognathism during sleep, to the introduction of a nasopharyngeal tube during sleep every night. When position training, oral appliances or a nasopharyngeal tube are used, their effect should be monitored by full night polysomnography. The best specific treatment for sleep apnoea is nasal continuous positive airway pressure. The main problem with nasal continuous positive airway pressure is the long-term compliance which should be assessed regularly over the years. In cases where nasal continuous positive airway pressure is not tolerated or compliance is bad, a surgical treatment can be proposed. Uvulopalatopharyngoplasty seems to give disappointing results. By contrast, maxillomandibular surgery is credited with the best results available as far as surgery is concerned, comparable to nasal continuous positive airway pressure.
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PMID:Management of sleep apnoea syndrome. 858 34

Treatment of obstructive sleep apnea (OSA) has developed over the last 25 years from tracheostomy to a variety of options, including weight loss, nasal continuous positive airway pressure (N-CPAP), pharyngeal surgery, and medications. None of these options is definitive or curative, except possibly weight loss. The most widely prescribed treatment is N-CPAP, but recently published studies using objective measurement of patient compliance show less than ideal compliance. Attempts have been made to design pharyngeal surgery according to the site of upper airway collapse or narrowing, as identified by various techniques in wakefulness. How representative these studies are of upper airway physiology in sleep is questionable. Recent studies have shown improved surgical success in correcting OSA. However, disturbing data are available in a limited number of patients that demonstrate worsening of the OSA months after a favorable response to surgery. More studies assessing the long-term outcome of pharyngeal surgery are needed. Several pharmacologic agents have been used to treat OSA. Results with any particular agent are not better than with N-CPAP or surgery. However, studies of subgroups of patients with OSA in which a particular pharmacologic agent may be specifically indicated, such as thyroxine in hypothyroidism, have not been conducted (to our knowledge). An algorithm for the approach to treatment recommendations is presented. Basic to this algorithm is an objective presentation of therapeutic options to the patient with OSA and a respect for the patient's preferences.
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PMID:Treatment of obstructive sleep apnea. A review. 904 18

Obstructive sleep apnea syndrome (OSAS) is characterized by multiple interruptions of airflow between periods of arousals. A key feature of OSAS is the 20- to 40-s cyclic pattern of electrophysiologic parameters. The periodicity of the OSAS-related phenomena is reminiscent of the natural electroencephalographic (EEG) arousal rhythm of non-rapid eye movement (NREM) sleep known as the cyclic alternating pattern (CAP). Morphologically, CAP consists of transient arousals (phase A) that periodically interrupt the tonic theta/delta activities of NREM sleep (phase B). Functionally, CAP translates a condition of sustained arousal instability oscillating between a greater arousal level (phase A) and a lesser arousal level (phase B). CAP is also related to the controls of the motor and autonomic mechanisms. On the basis of the information simultaneously derived from EEG activities, muscle tone, and neurovegetative responses, it is possible to distinguish three subtypes of A phases corresponding to different levels of arousal power: A1 (dominated by EEG synchronization and weak activation of polygraphic variables); A2 (mixture of EEG synchronization/desynchronization and intermediate activation of polygraphic variables); and A3 (dominated by EEG desynchronization and strong activation of polygraphic variables). Unlike standard criteria, CAP parameters offer a more suitable perspective for evaluating sleep pathologies in which brief and frequent arousals appear as a prominent feature. The present study aimed at (a) assessing CAP parameters in OSAS patients and (b) investigating the reciprocal interactions between CAP and the cyclic variations in respiratory rate. Twelve obese middle-aged OSAS subjects complaining of daytime sleepiness were polygraphically compared with age-matched and gender-matched volunteers in good health and with no complaints about sleep and wakefulness (controls). In OSAS patients, conventional parameters showed predictable decrements in total sleep time, slow wave sleep, and REM sleep and increases in stage 1 and nocturnal awakenings. Sleep fragmentation was associated with a significant enhancement of CAP and of the A phases with longer and more desynchronized EEG patterns (especially A3). The increase of A3 subtypes permitted scoring and detecting CAP also in REM sleep. The great majority of respiratory pauses (96% in NREM and 80% in REM sleep) were coupled with CAP. All CAP-related respiratory events rose in close temporal connection with a phase B, while effective breathing was always recovered during phase A (especially A2 and A3 subtypes). These data suggest that (a) phase B of CAP offers a vulnerable background for upper airway collapse and for attenuation of biochemical and neural mechanisms in the control of the ventilatory drive and (b) survival in OSAS patients is effected by the enhancement of the strongest components of the natural arousal rhythm at sleep quality's expense.
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PMID:Polysomnographic analysis of arousal responses in obstructive sleep apnea syndrome by means of the cyclic alternating pattern. 884 69

These clinical guidelines, which have been reviewed and approved by the Board of Directors of the American Sleep Disorders Association, provide recommendations for the practice of sleep medicine in North America regarding the role of surgical procedures in the treatment of obstructive sleep apnea in adults. Surgical procedures that are considered include: uvulopalatopharyngoplasty, laser midline glossectomy and lingualplasty, inferior sagittal mandibular osteotomy and genioglossal advancement with hyoid myotomy and suspension, maxillomandibular osteotomy and advancement, and tracheotomy. Whenever possible, conclusions are based on evidence from review of the literature. In instances where scientific data are absent, insufficient or inconclusive, recommendations are based on consensus of opinion. The Standards of Practice Committee of the American Sleep Disorders Association appointed a task force to review the topic, the surgical treatment of obstructive sleep apnea. Based on the review and consultation with specialists, the subsequent recommendations were developed by the Standards of Practice Committee and approved by the Board of Directors of the American Sleep Disorders Association. Recommendations are as follows: The presence and severity of obstructive sleep apnea must be determined before initiating surgical therapy. The desired treatment outcomes include resolution of the clinical signs and symptoms of obstructive sleep apnea and the normalization of the apnea-hypopnea index and oxyhemoglobin saturation levels. Because of the complexity of airway narrowing or collapse during sleep, any one surgical procedure may not eradicate a patient's sleep apnea. A stepwise approach to surgical management is acceptable if the patient is advised at the onset of treatment about the likelihood of the success of each procedure and that multiple operations may be necessary. After the surgical site has healed, a follow-up evaluation, including an objective measure of respiration and quality of sleep, must be performed to ensure that the abnormalities noted in the original study are corrected.
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PMID:Practice parameters for the treatment of obstructive sleep apnea in adults: the efficacy of surgical modifications of the upper airway. Report of the American Sleep Disorders Association. 885 38

This paper, which has been reviewed and approved by the Board of Directors of the American Sleep Disorders Association, provides the background for the Standards of Practice Committee's parameters for the practice of sleep medicine in North America. The intent of this paper is to provide an overview of the surgical treatment of obstructive sleep apnea syndrome, to provide the basis for the American Sleep Disorders Association's practice parameters on this subject and to share our findings of metanalysis of previously published studies regarding uvulopalatopharyngoplasty. We searched MEDLINE from January 1966 through April 1993, with an update in February 1995, to provide a review of the application of surgical modifications of the upper airway to treat adults with obstructive sleep apnea syndrome. Operations to treat obstructive sleep apnea syndrome include nasal septal reconstruction; uvulopalatopharyngoplasty; uvulopalatopharyngoglossoplasty; laser midline glossectomy; lingualplasty; inferior sagittal mandibular osteotomy and genioglossal advancement, with hyoid myotomy and suspension (the entire process is referred to as GAHM); maxillomandibular osteotomy and advancement, and tracheotomy. Papers included in metanalysis provided preoperative and postoperative polysomnographic data on at least nine patients treated with uvulopalatopharyngoplasty for their obstructive sleep apnea. Analysis of the uvulopalatopharyngoplasty papers revealed that this procedure is, at best, effective in treating less than 50% of patients with obstructive sleep apnea syndrome. The site of pharyngeal narrowing or collapse, although identified by different and unvalidated methods, has a marked effect on the probability of success of uvulopalatopharyngoplasty. Patients who achieve a favorable response with uvulopalatopharyngoplasty tend to have less severe obstructive sleep apnea than those who do not. For patients who demonstrate retrolingual narrowing or collapse, other surgical modifications have been described, such as lingualplasty, GAHM, and maxillomandibular osteotomy and advancement. The studies to support the use of the surgical treatment of obstructive sleep apnea syndrome contain biases related to small sample size, limited follow-up and patient selection.
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PMID:The efficacy of surgical modifications of the upper airway in adults with obstructive sleep apnea syndrome. 885 39

Obstructive sleep apnea (OSA) is a disorder in which there is repetitive collapse and closing of the pharynx during sleep. There is growing evidence to suggest that this disorder is a major cause of essential hypertension (EH) and that successful treatment of OSA can reduce the blood pressure (BP) significantly. In addition many other patients with EH have milder forms of sleep related breathing disorders (SRBD) like snoring, and upper airway resistance syndrome (UARS) which, while not as severe as OSA, may be severe enough to also cause systemic hypertension. We therefore propose a unifying hypothesis-that many patients with EH may have sleep related breathing disturbances (SRBD) and treatment of these disorders may improve the BP. SRBD could also explain many of the epidemiological, clinical, hereditary, biochemical, hematological and physiological characteristics seen in EH. In addition, many types of secondary hypertension (those caused by excessive alcohol intake, chronic renal failure, diabetes, hypothyroidism or acromegaly) have a higher than normal prevalence of OSA and OSA may contribute to the hypertension and organ damage found in these conditions as well. Thus SRBD may play an important role in the production of many cases of essential and secondary hypertension, and their early detection and treatment could reduce the hypertension and organ damage seen in these conditions.
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PMID:Essential and secondary hypertension and sleep-disordered breathing: a unifying hypothesis. 887 97

Techniques for surgical correction of the soft palate are used commonly to treat obstructive sleep apnea syndrome (OSAS), but a satisfactory cure cannot be ensured because such techniques usually involve localized correction of the upper airways (UA) whereas UA collapse during sleep involves the entire length. The development of correction techniques for the entire extension of the UA may help to solve this problem. We report the first two cases of multilevel UA surgical reconstruction in OSAS performed in Spain. The excellent results obtained favor routine use of this type of surgery once it has been validated in clinical practice.
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PMID:[Surgical multiple level reconstruction of the upper airways for treatment of obstructive sleep apnea. Two clinical cases]. 904 91

Investigators have postulated that pharyngeal collapse during sleep in patients with obstructive sleep apnea (OSA) may be alleviated by stimulating the genioglossus. The effect of electrical stimulation (ES) of the genioglossus on pharyngeal patency was examined in an isolated feline upper airway preparation and in apneic humans during sleep. We found that stimulation of the genioglossus (n = 8) and of the hypoglossal nerve (n = 1) increased maximum airflow through the isolated feline upper airway in humans during sleep. Additional findings in the isolated feline upper airway suggest that such increases in airflow were due to decreases in pharyngeal collapsibility. The evidence suggests that improvements in airflow dynamics with electrical stimulation are due to selective recruitment of the genioglossus, rather than due to nonspecific activation of the pharyngeal musculature or arousal from sleep. The implications of these results for future therapy with ES are discussed.
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PMID:Electrical stimulation of upper airway musculature. 908 33


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