Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Aminophylline has been demonstrated to increase in vitro contractility in skeletal muscle, including diaphragm. In vivo studies report significant increases in diaphragm contractility in patients with chronic obstructive pulmonary disease but only small increases in control subjects. The present study determined the effects of aminophylline on strength and fatigability in the diaphragm, the biceps brachii, and the quadriceps of normal individuals. Seven healthy subjects were tested with placebo and drug conditions on separate days in a randomized, double-blind fashion. Mean theophylline levels of 15 +/- 2 mg/L SD were maintained by constant intravenous infusion. Strength of the diaphragm was measured as maximum inspiratory pressure. Strength of the biceps and quadriceps were measured isometrically during arm flexion (90 degrees) and leg extension (115 degrees) against an electronic load cell. Fatigue was measured as the decrease in tension during a 30-second contraction and during a 6-minute period of alternating 5-second maximal contraction and 5-second rest. Therapeutic levels of theophylline had no effect on strength or fatigability during a maximal contraction in any muscle group studied.
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PMID:In vivo effects of theophylline on diaphragm, bicep, and quadricep strength and fatigability. 320 50

Exercise testing is traditionally performed with leg exercise on either a treadmill or a bicycle ergometer. Many of these tests are terminated before dyspnoea occurs because of leg fatigue, arthritic pain, or claudication. A study was carried out to determine whether arm ergometry testing might serve as an alternative method to leg testing in eight patients with chronic obstructive lung disease. The patients had mild to moderate dyspnoea on exertion and required bronchodilator treatment. They had smoked an average of 62 pack years and had a mean FEV1 of 1.88 l. Arm and leg ergometry yielded similar levels of maximum ventilation (arm 47.2, leg 48.6 l/min), maximum heart rates (126 v 124 beats/min), maximum tidal volume (1.5 v 1.6 l), and respiratory rate (30 v 29 breaths/min); but maximum oxygen consumption (1120 v 966 ml/min), maximum power output (62 v 26 w), and oxygen pulse (9.1 v 7.8 ml/beat) were all higher with leg than with arm ergometry. In addition, ventilation and heart rate at a given level of oxygen consumption were higher for arm than for leg work during both submaximal and maximal exercise. It is concluded that arm ergometry offers an alternative testing method to leg testing in patients with moderate chronic obstructive lung disease.
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PMID:Comparison of arm and leg ergometry in patients with moderate chronic obstructive lung disease. 322 62

A patient with a history of chronic obstructive pulmonary disease going back more than 20 years was treated with a combination of chiropractic manipulation, nutritional advice, therapeutic exercises, and intersegmental traction. Improvements were noted in forced vital capacity, forced expiratory volume in one second, coughing, fatigue, and ease of breathing (sign test significant at 0.005 level). Improvement was also noted in laryngospasm. Studies are made and speculation as to the mechanism of the treatment effect is provided.
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PMID:Chiropractic management of chronic obstructive pulmonary disease. 276 95

Malnutrition may be an important complicating factor in acute and chronic lung disease. Animal studies have demonstrated significant atrophy of diaphragm muscle fibers following prolonged undernutrition resulting in a marked reduction in diaphragm muscle strength as well as alteration in other contractile and fatigue properties of the muscle. In severe chronic obstructive pulmonary disease (COPD), malnutrition is common and may, in conjunction with the influences of hyperinflation on diaphragm performance, predispose to respiratory muscle fatigue and failure. The course of progressive weight loss in patients with COPD is not known but may, in part, be related to a "hypermetabolic" state arising from an increased oxygen consumption of the respiratory muscles secondary to enhanced resistive loads and impaired mechanical efficiency of the respiratory muscles. Reports of the impact of nutritional repletion on respiratory muscle performance in critically ill patients, as well as in patients with COPD, are preliminary. Further studies are necessary to establish whether such measures impact meaningfully on both the morbidity and mortality of these patients.
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PMID:Nutrition and the respiratory muscles. 329 32

Recent investigations have shown that theophylline improves diaphragmatic contractility of the respiratory muscles in isolated muscle preparations in animals and in normal human subjects. It has also been demonstrated that theophylline can reverse diaphragmatic fatigue and prevent fatigue of the diaphragm when given prophylactically. These effects have also been demonstrated in patients with severe chronic obstructive pulmonary disease, all of whom retained CO2 (PaCO2 53 +/- 3 mm Hg) and had hypoxia (PaO2 57 +/- 8 mm Hg). Theophylline, which increases respiratory muscle strength and delays the onset of diaphragmatic fatigue therefore could be a very useful agent in the treatment of patients with chronic airway obstruction.
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PMID:Effect of theophylline on diaphragmatic muscle function. 329 24

This study sought answers to 2 questions: (1) Is severe dyspnea to the point of exhaustion regularly accompanied by diaphragmatic fatigue in patients with moderately severe chronic obstructive pulmonary disease (COPD)? (2) When diaphragmatic fatigue occurs in such patients, does theophylline prevent or delay its onset? Eight eucapnic patients with moderately severe COPD were subjected to 2 different stresses to the point of severe dyspnea requiring cessation of the stress. The stresses were cycle exercise and inspiratory resistive breathing, the latter requiring a tidal Pdi equal to 60% of Pdimax. Despite incapacitating dyspnea, objective evidence of diaphragmatic fatigue was not encountered during cycle exercise. During inspiratory resistive breathing, diaphragmatic fatigue was encountered in all patients as defined by consistent inability to attain a target Pdi during final moments of the resistance run. Patients were uniformly extremely dyspneic at this point. In neither stressful maneuver did oral sustained-release theophylline show a convincing or significant advantage over placebo when administered in a randomized double-blind crossover protocol. These results suggest that the diaphragmatic fatigue encountered in this sort of COPD patient may be of predominantly central rather than peripheral (myogenic) origin and that theophylline may not be effective in this type of fatigue.
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PMID:Dyspnea and diaphragmatic fatigue in patients with chronic obstructive pulmonary disease. Responses to theophylline. 334 44

Many patients with chronic obstructive pulmonary disease (COPD) report greater limitation for activities involving the upper extremities than the lower extremities. Exercise training has generally emphasized lower-extremity exercise. We designed and evaluated two simple, practical, and widely applicable upper-extremity training programs in 45 patients with COPD participating concurrently in a comprehensive, multidisciplinary pulmonary rehabilitation program. Patients were randomly assigned to one of the following three groups: (1) gravity-resistance (GR) upper-extremity training; (2) modified proprioceptive neuromuscular facilitation (PNF) upper-extremity training; or (3) no upper-extremity training (control). Patients were evaluated before and after at least six weeks of uninterrupted training. Twenty-eight patients completed the study. Compared to controls, both GR and PNF patients demonstrated improved performance on tests specific to the training performed (upper-extremity performance test, maximal level and endurance on isokinetic arm cycle). There were no significant changes on isotonic arm cycle, ventilatory muscle endurance, or simulated activities of daily-living tests. Ratings of perceived breathlessness and fatigue decreased significantly in all groups for several tests. We conclude that specific upper-extremity training may be beneficial in the rehabilitation of patients with COPD and warrants further investigation.
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PMID:Upper extremity exercise training in chronic obstructive pulmonary disease. 334 25

Described is a 67-year-old man whose initial symptoms evoked an obesity-hypoventilation syndrome. Polysomnography showed hypopneas associated with O2 desaturation episodes, and no apnea; maximal changes were noted during REM sleep. A few months later, in spite of marked weight loss, acute alveolar hypoventilation occurred and necessitated mechanical ventilatory support. Tracheostomy was performed. The patient appeared to be dependent on nocturnal ventilatory assistance. Diaphragmatic paralysis was noted in addition to clinical and electrodiagnostic evidence of amyotrophic lateral sclerosis. While the patient was not ventilated, a nocturnal recording of SaO2 again revealed desaturation episodes partly corrected by O2 2 L/min administered through the tracheostomy tube. With volume-controlled ventilation, desaturations completely disappeared, although no oxygen enrichment of the air was provided. We speculate that sleep disorders with hypopneas and O2 desaturation episodes were the initial symptoms of amyotrophic lateral sclerosis. This leads us to suggest that nonspecific respiratory muscle fatigue frequently seen in COPD might be included in the hypothetic causes of nocturnal hypoxemia.
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PMID:Amyotrophic lateral sclerosis presenting with sleep hypopnea syndrome. 337 Nov 13

Methylxanthines and particularly caffeine are known to increase skeletal muscle contractility. Recently, it has been shown that theophylline improves diaphragmatic contractility of the respiratory muscles both in isolated muscle preparations and in animals and normal human beings. Furthermore, it has been demonstrated that theophylline reverses diaphragmatic fatigue and prevents fatigue of the diaphragm when it is given prophylactically. Finally, recent evidence indicates that theophylline improves diaphragmatic function in patients with chronic obstructive pulmonary disease, all of whom retained CO2 (PaCO2 43 +/- 3 mm Hg) and had hypoxia (PaO2 57 +/- 8 mm Hg). Patients both improved transdiaphragmatic pressure and were less susceptible to fatigue. These data strongly suggest that theophylline, which increases respiratory muscle strength and delays the onset of diaphragmatic fatigue, could be a very useful agent in the treatment of patients with chronic airway obstruction.
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PMID:Effect of theophylline on diaphragmatic and other skeletal muscle function. 353 59

To evaluate the relationship between diaphragmatic pressure (Pdi) waveform and electromyographic (EMG) signs of diaphragmatic fatigue (DF), 11 chronic obstructive pulmonary disease (COPD) subjects underwent a 12-stage graded treadmill exercise test (GXT). No COPD subjects completed the GXT; all stopped exercising due to dyspnea. We then used the crural diaphragmatic EMG (EMGdi) to divide the COPD subjects into a group that exhibited EMGdi signs of fatigue during the GXT (i.e., F group) and one that did not (i.e., NF group); three COPD subjects were classified as F, and eight COPD subjects were classified as NF. At end exercise, F and NF groups did not differ with respect to peak inspiratory Pdi swing (peak Pdi); however, they did differ with respect to percent of peak Pdi manifest at 50 and 90% of inspiratory time (TI). At 50% TI, NF = 88 +/- 3%, F = 60 +/- 1%, P less than 0.01; likewise at 90% TI, NF = 58 +/- 5%, F = 12 +/- 10%, P less than 0.01. Since peak Pdi occurred in both groups during the initial 50% of TI, these data indicate that the F group maintained Pdi less well than the NF group during the latter half of TI. Based on the above results and other data in the manuscript, we suggest that this change in Pdi waveform can predict EMG signs of DF.
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PMID:Diaphragmatic pressure waveform can predict electromyographic signs of diaphragmatic fatigue. 359 39


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