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Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Theophylline alleviates central and obstructive apneas of prematurity, and may improve adult obstructive sleep apnea. One mechanism of action appears to be a stimulatory effect on the motor output to upper airway dilator muscles. The purpose of the present study was to determine whether theophylline might have a second mechanism of action, namely that of improving the force and/or endurance of the pharyngeal dilator musculature. Rat sternohyoid muscle strips were studied in vitro and compared to diaphragm strips. The isometric twitch force and twitch kinetics of neither muscle were altered by theophylline (100 mg/l). Theophylline significantly slowed the rate at which the diaphragm fatigued during intermittent 40-Hz stimulation (p < 0.001). In contrast, theophylline produced no improvement in the fatigue resistance of the sternohyoid muscle. The degree of force potentiation during the early portion of the fatigue protocol was not altered by theophylline for either muscle. These results suggest that the mechanism by which theophylline improves obstructive apnea is unlikely to be due to a beneficial effect on pharyngeal dilator muscle force or endurance.
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PMID:Effects of theophylline on pharyngeal dilator and diaphragm muscle contractile properties. 896 72

The author's goal was to investigate the effects of surgical treatment on psychophysiological measurements in 17 patients with obstructive sleep apnea syndrome (OSAS) and also to clarify the improvement process of each evaluation. Given the changes in respiratory disturbance and sleep architecture, it was obvious that surgical treatment had therapeutic effects on OSAS patients a few months after the surgery. In that process, a dissociation between objective and subjective sleepiness was observed. The improvement in objective sleepiness [multiple sleep latency test (MSLT)] was more delayed than the improvement in subjective sleepiness (Stanford Sleepiness Scale, Spaceaeromedicine fatigue checklist). The improvement of MSLT was associated with an improvement in sleep fragmentation. This finding suggests that the disruption of sleep continuity accompanied by respiratory disturbance might be responsible for the occurrence of objective sleepiness. It can be concluded that the effective management of OSAS needs to address the full range of psychophysiological manifestations, especially objective measurement of daytime sleepiness.
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PMID:Improvement in excessive daytime sleepiness after surgical treatment for obstructive sleep apnea syndrome. 917 40

We studied 20 patients with obstructive sleep apnea syndrome (OSAS) prospectively, before and after administering continuous positive airway pressure through a nasal mask (CPAPn) at night for 10 months, with the aim of determining the effects of ventilatory pattern of long-term treatment with CPAPn in OSAS patients. The following data were collected for all patients: anthropometric variables, lung function test results, arterial gasometric readings at rest, oxygen alveolar-arterial differential [Dif(A-a)O2)], central respiratory function variables at rest and during hypercapnic stimulus. Mean duration (range) of treatment with CPAPn was 12.5 (10-18) months. We observed a significant increase in PaO2 (p = 0.01) and a decrease in PaCO2 (p = 0.02) with slight variations in body weight and no changes in lung mechanics or in Dif(A-a)O2. The ventilatory pattern at rest showed an increased in VE and in respiratory frequency (p = 0.0003 and p = 0.033, respectively) with non significant changes in VT. The VT/Ti ratio increased (p = 0.015) and P0.1 decreased slightly (p = 0.025). We found no significant changes in the CO2 response slopes of VE or P0.1. In conclusion, CPAPn improves hypoxemia and hypercapnia in OSAS patients, above all by increasing baseline basal ventilation. The exact mechanisms implicated are poorly understood, but our data suggest a certain direct or indirect effect on respiratory muscles, reducing muscle fatigue, thus favoring greater availability during sleep.
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PMID:[Long-term effects of nasal continuous positive airway pressure on ventilatory patterns of patients with obstructive sleep apnea syndrome]. 928 May 59

Aviation safety reports indicate that many incidents are related to fatigue. Obstructive sleep apnea (OSA) is characterized by irregular snoring with repeated apnea episodes during sleep and excessive daytime sleepiness. Deprived of sleep, patients suffer from daytime sleepiness and involuntary sleep attacks. The prevalence of OSA among adult men is more than one percent, 0.5% in women. Predisposed are men aged 40-65 yr. Many patients, including pilots, are unaware of their sleeping disturbance and the symptoms are not easily recognized. Therefore, this condition may not be discovered during a regular health examination. However, this condition can be effectively treated. In our opinion, pilots suffering from OSA do not necessarily have to lose their certificate. Diagnosis and treatment can be conducted, followed by regular check-ups. We suggest that questions about sleep be included in pilots' health examinations.
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PMID:Case report: obstructive sleep apnea--an air safety risk. 940 66

Obstructive sleep apnea (OSA) is a potentially life-threatening sleep disorder that is estimated to affect 20 million Americans. OSA is characterized by repeated collapse of the upper airway during sleep, which produces breathing pauses and interruption of the sleep cycle. Symptoms include heavy snoring, many nighttime arousals, sleep deprivation, chronic fatigue and a variety of cardiovascular diseases. While many treatments are advocated for OSA, oral devices have been shown to be effective. Dental technicians and dentists may be involved in the construction of oral appliances for patients with OSA. In this article, a synopsis of various treatment modalities is presented, and the construction of two appliances is described and illustrated.
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PMID:Custom devices for sleep apnea treatment. 951 77

Obstructive sleep apnea (OSA) syndrome occurs in 4% to 9% of middle-aged men and in 1% to 2% of middle-aged women. The incidence of OSA among morbidly obese patients is 12- to 30-fold higher. The pathophysiology of OSA is complex and incompletely understood. The important clinical symptoms of OSA include snoring, daytime sleepiness, restless sleep, morning fatigue, and headaches. The diagnosis is made by polysomnography. The possible sequelae of OSA are hypertension, left and right ventricular hypertrophy, sudden cardiovascular death, and increased risk for brain infarction. Nasal continuous positive airway pressure (nCPAP) appears to be the recommended treatment for OSA. Morbidly obese patients may also benefit from weight reduction gastric surgery.
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PMID:Obstructive sleep apnea in the obese. 971 28

Thirty-three subjects (28 men, five women) with complete or incomplete cervical cord injury representing a wide range of neurological impairment were investigated with regard to the prevalence of Obstructive Sleep Apnea (OSA). The relation between OSA and neurological function, respiratory capacity, body mass index and symptoms associated with OSA were studied. Overnight sleep recordings employed combined oximetry and respiratory movement monitoring. Pulmonary function tests included static and dynamic spirometry, maximal static inspiratory and expiratory pressures at the mouth. The subjects answered a questionnaire concerning sleep quality and tiredness. The prevalence of OSA was 15% (5/33) in this nonobese cervical cord injury study population. Nine percent of the subjects (3/33) fulfilled the criteria for obstructive sleep apnea syndrome, but daytime sleepiness or fatigue were also common in subjects without OSA. There was an inverse correlation between oxygen desaturation index and American Spinal Injury Association (ASIA) motor score in the subjects with complete injury, while there was no such correlation in the whole study group. There were significant correlations between maximal inspiratory and expiratory pressures and vital capacity and between ASIA motor score and vital capacity.
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PMID:Obstructive sleep apneas in relation to severity of cervical spinal cord injury. 977 46

An analysis of the way the pharyngeal musculature modulates the caliber of the pharynx is important to better understand and treat obstructive sleep apnea syndromes. The caliber of the pharynx at the soft palate depends on the action of the tensor veli, the palatoglossus, the palatopharyngeus and the uvula muscles. At the ligual level, the action of the genioglossus and the geniohyoideus predominate. These different muscle groups contract in co-ordination before the diaphragm contracts. Their activity is diminished and disorganized during sleep. These muscles appears to have a histological composition adapted to short-duration intense contractions making them vulnerable to fatigue. In apneic patients, these muscles are solicited constantly. Muscular lesions related to overwork have been suggested. The histological composition of these muscles is modified in apneic patients compared with non-apneic subjects (increased number of type IIa fibres), the expression of an adaptive process. The degree of adaptation varies depending of the pharyngeal level considered. Similar to their reflex stimulation, the response of these pharyngeal muscles to increased resistance is probably greater at the soft palate level. Greater solicitation of palatine muscles associated with their greater vulnerability to fatigue could explain why obstruction is particularly important at this level. A study of the mechanical and histological properties of the pharyngeal musculature is required for a better understanding of the occlusive mechanisms of the upper airways and must be undertaken before initiating therapeutic stimulation of these muscles.
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PMID:[Pharyngeal muscles and sleep obstructive apnea syndrome]. 1009 Dec 60

We report on a 2 1/2-year-old boy who is currently ventilated at home by positive pressure ventilation through a nasal mask during the night because of congenital central hypoventilation syndrome (CCHS). Up to age 2 he had developed normally. A reevaluation was performed because of symptoms suggestive of obstructive sleep apnea syndrome (OSAS), including snoring, nocturnal sweating, frequent nighttime awakenings, speech impairment, daytime fatigue, and failure to thrive. A sleep study indicated obstructive apnea episodes lasting up to 40 s and arterial desaturations below 50% during spontaneous sleep. During mechanical ventilation snoring persisted, and capillary PCO2 rose to 60 mm Hg. Partial upper airway obstruction, leaking around the mask, and arousal movements developed on passive flexion of the neck to 20 degrees. After adenoidectomy, symptoms of OSAS resolved. There were no more obstructive apneas during spontaneous sleep, but obstructive apneas could be provoked by neck flexion to 20 degrees. During ventilation, neck flexion of 20 degrees was tolerated, but a 40 degrees flexion led to partial obstruction. In CCHS patients, the problem of upper airway obstruction is rarely noted because most patients are ventilated through a permanent tracheostomy. Today, noninvasive ventilation strategies are becoming more common. Reduced activity of upper airway muscles and impaired reflex mechanisms could lead to upper airway obstruction during face mask positive pressure ventilation in children with CCHS. Enlarged adenoids worsened this problem in our patient, leading to insufficient ventilation and OSAS. Adenoidectomy resolved symptoms of OSAS and enabled successful nasal mask ventilation. Close follow-up of the patient avoided hypoxia and sequelae from OSAS such as pulmonary hypertension.
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PMID:Resolution of obstructive sleep apnea syndrome after adenoidectomy in congenital central hypoventilation syndrome. 1034 14

Obstructive sleep apnea hypoventilation syndrome (OSAHS) is an important public health problem. However, major gaps exist in our knowledge about the clinical features of this disorder in the pediatric age group. The purpose of this study was to examine clinical features of OSAHS diagnosed by polysomnography in otherwise healthy children. In this cross-sectional study, 326 children without underlying medical conditions (5.8+/-3.0 years, range 1-12 years; 56% male) were recruited from patients referred by primary care and otorhinolaryngology physicians for evaluation of snoring and difficulty breathing. Ethnic group distribution was African-American (38%), Caucasian (30%), and Hispanic (31%). Complaints of daytime tiredness or sleepiness were reported in 29% of the children. All children underwent overnight polysomnography (N = 330 studies). OSAHS was diagnosed in 59% of the children, based on polysomnographic criteria. The remaining children had either primary snoring (25%); no snoring (10%), or upper airway resistance syndrome (6%). Neither male gender nor obesity increased the likelihood for the diagnosis of OSAHS. However, the incidence of obesity in the study population (28%) was more than twice that of the general pediatric population. African-American children had a greater likelihood for OSAHS diagnosis compared to Hispanic or Caucasian children. Daytime complaints of sleepiness or tiredness were not more common in children diagnosed with OSAHS than in the children without OSAHS. As expected, tonsillar hypertrophy increased the likelihood of OSAHS diagnosis. In summary, many of the clinical features of childhood OSAHS are in marked contrast to those in adults.
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PMID:Clinical features of obstructive sleep apnea hypoventilation syndrome in otherwise healthy children. 1038 92


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