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)

In 10 sedated paralyzed mechanically ventilated chronic obstructive pulmonary disease (COPD) patients, we measured the inspiratory mechanical work done per breath on the respiratory system (WI,rs). We measured the tracheal and esophageal pressures to assess the lung (L) and chest wall (W) components of WI and used the technique of rapid airway occlusion during constant-flow inflation to partition WI into static work [Wst, including work due to intrinsic positive end-expiratory pressure (WPEEPi)], dynamic work due to airway resistance, and the additional resistance offered by the respiratory tissues. Although the patients were hyperinflated, the slope of the static volume-pressure relationships of the lung did not decrease with inflation volume up to 0.8 liter. WI,W was similar in COPD patients and normal subjects. All components of WI,L were higher in COPD patients. The increase in Wst,rs was due entirely to WPEEPi. Our data suggest that, during spontaneous breathing, COPD patients would probably develop inspiratory muscle fatigue, unless continuous positive airway pressure were applied to reduce WPEEPi.
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PMID:Partitioning of work of breathing in mechanically ventilated COPD patients. 828 24

Two hundred seventy severely hypoxemic (PaO2 < or = 55 mm Hg: mean +/- SD = 48 +/- 6) COPD patients (232 men) were selected for long-term oxygen therapy (LTOT). They were old (mean = 66 +/- 8 years), with severe airflow limitation (FEV1 = 30 +/- 12 percent of predicted), some CO2 retention (PaCO2 = 47 +/- 9 mm Hg), and compensated respiratory acidosis. Eighteen percent of the patients presented some complicating pleuropulmonary diseases (pleural thickening, sequelae of tuberculosis, etc). Overall survival proportion was poor: 70, 50, and 43 percent at 1, 2, and 3 years, respectively. The Cox model showed that the factors which independently reduced survival were lower CO transfer coefficient, smaller intrathoracic gas volume, more severe bronchial obstruction, the fact that oxygen administration did not increase PaO2 above 65 mm Hg, increasing age, and the presence of chest wall abnormalities. When the patients were divided into three groups according to mortality risk, the mean clinical and functional profile of the high-mortality risk group was consistent with the prevalence of emphysematous lesions. Moreover, the best survivors fitted better into the "bronchitic" type; they showed a higher mean PaCO2, suggesting that some degree of hypoventilation could delay muscular fatigue and improve survival. The difference in the proportion of "emphysematous" and "bronchitic" patients is a possible explanation for the variability of the mortality rate reported in literature.
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PMID:Prognosis of severely hypoxemic patients receiving long-term oxygen therapy. 830 23

Diaphragmatic muscle fatigue (DMF) has long been recognized as causing and developing respiratory failure in patients with chronic obstructive pulmonary disease (COPD). Paradoxical motion of thoraco-abdomen is one of asynchronous breathing pattern, which is clinical sign of DMF. Thoracoabdominal motion curves were recorded with impedance respirograph (IRG). Indexes, alpha and M on IRG correlated well to the degrees of asynchronous breathing movement. 30 patients with COPD, their IRG showed paradoxical motion of thoraco-abdomen were divided randomly into two groups of 15 cases. Group A was treated intravenously with Sheng Mai injection at first and with glucose later. Among patients of group B, preceding Sheng Mai injection was glucose. IRG were recorded before and after treatment. Results showed that the IRG of 26 patients treated with Sheng Mai injection changed from paradoxical pattern to sychronous one. The difference of the indexes alpha and M before and after treatment of Sheng Mai injection was statistically significant (P < 0.001). Only one patient treated with glucose changed from paradoxical to sychronous pattern. The difference of the indexes between treated and non-treated with glucose was not statistically significant (P < 0.05). This study suggest that Sheng Mai injection has a positive inotropic effect on fatigued diaphragmatic muscle.
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PMID:[Effects of sheng mai injection on thoracoabdominal motion]. 833 46

Many daily activities, from basic grooming to employment tasks, require adequate unsupported arm endurance (UAE). We developed an electromechanical device to measure UAE endurance. The purpose of this study was to standardize the instrument for two rates of arm motion, moderate and slow, in 18 normal adult subjects (FEVI = 3.7L +/- .78, FVC = 4.2L +/- .74, FEV1/FVC = 1.1 +/- .08). Exercise endurance limits, and the following metabolic, ventilatory, and sensation responses were determined at rest prior to exercise and at end-exercise limits for both rates of UAE:minute ventilation (Ve), tidal volume (VT), respiratory rate (RR), duty cycle (Ti/Ttot), oxygen uptake (VO2), carbon dioxide production (VCO2), inspiratory flow (VT/Ti), heart rate (HR), and visual analog scale measurements (VAS) of dyspnea (D), respiratory effort (RE), and arm fatigue (AF). Significance increases from baseline rest were shown at the endurance limits for both rates of UAE in: VO2, VCO2, Ve, VT, RR, VT/Ti, HR, VAS-D, VAS-RE, and VAS-AF. There were no changes in Ti/Ttot and SaO2 with UAE. Peak VO2, RR, Ve, VT/Ti, and VAS-D with moderate exercise were significantly greater than slow UAE; and there was a trend increase in peak HR for moderate as opposed to slow rate UAE. Despite these differences, the endurance time between the two rates of UAE were similar. These data provide standards against which UAE in COPD can be evaluated.
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PMID:Instrument development in the measurement of unsupported arm exercise endurance in normal adult subjects. 850 57

Some conditions that predispose to ventilatory failure increase the work of breathing (chronic obstructive pulmonary disease [COPD], obesity, kyphoscoliosis), whereas others cause severe respiratory muscle weakness. Specific reasons for muscle weakness include critical illness (electrolyte imbalance, acidemia, shock, sepsis), chronic illness (poor nutrition, cachexia), and neuromuscular diseases. Inspiratory muscle weakness from mechanical disadvantage to the diaphragm is characteristic of asthma and COPD. The increased work of breathing combined with muscle weakness increases the pressure needed to inspire a breath and decreases maximal inspiratory pressure. When this pressure exceeds 0.4, dyspnea and inspiratory muscle fatigue ensue. One way to lower this pressure and avert fatigue is to lower the tidal volume. Ventilatory drive is high, not low, in ventilatory failure. Concomitant shortening of inspiration and breath duration cause the small tidal volume and increased respiratory rate. Gas exchange is compromised by ventilation/perfusion imbalance, and the ratio of dead space to tidal volume is also increased by rapid, shallow breathing. Reduction in tidal volume minimizes dyspnea, but the small tidal volume is inadequate for gas exchange. Acute treatment of respiratory muscle failure involves respiratory muscle rest through mechanical ventilation and removal of noxious influences (infection, metabolic disarray), whereas chronic treatment involves rebuilding the contractile apparatus by nutritional repletion and training.
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PMID:Respiratory muscles and ventilatory failure: 1993 perspective. 850 1

The excessive load placed on inspiratory muscles when patients with COPD exercise could lead to fatigue and contribute to exercise limitation. Slowing of maximal relaxation rate (MRR) of skeletal muscle is an early index of the fatiguing process. We investigated whether inspiratory muscle MRR slows when patients with COPD walk to exhaustion. We studied nine well-trained and motivated patients with stable severe COPD (mean FEV1: 0.7 L, 28% predicted). Each subject performed sniff maneuvers before and after walking on a treadmill until they were forced to stop because of dyspnea. Esophageal (Pes), gastric, and transdiaphragmatic pressures were measured using balloon-tipped catheters. MRR was calculated as the percent Pes drop/10 ms. In the first minute after exercise there was a mean decrease of Pes MRR of 42% (range, 21 to 65%) (p < 0.01), which returned to baseline within 3 to 5 min. The fall in MRR indicates that the inspiratory muscles of patients with COPD walking to exhaustion are sufficiently heavily loaded to initiate the fatiguing process.
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PMID:Exhaustive exercise slows inspiratory muscle relaxation rate in chronic obstructive pulmonary disease. 856 33

The bronchodilator efficacy, safety, and persistence of effect of the anticholinergic agent ipratropium bromide and the beta-adrenergic agonist albuterol, both given by nebulization, were compared in 223 patients with stable, severe chronic obstructive pulmonary disease (COPD). The study was a randomized, double-blind, parallel group trial conducted over 85 days. Patients took the study drugs (either 500 micrograms of ipratropium bromide or 2.5 mg of albuterol) three times daily on an outpatient basis throughout the study. The acute bronchodilator responses to nebulized ipratropium bromide and albuterol were studied on days 1, 43, and 85. The forced expiratory volume in 1 second (FEV1) response was similar for both drugs on day 1 (33% peak increase after ipratropium bromide and 36% peak increase after albuterol). However, albuterol's effect on FEV1 decreased over time. Clinical improvement was noted in both study groups, but the ipratropium bromide group had a greater symptomatic benefit. Patients receiving ipratropium bromide scored higher on a quality-of-life questionnaire evaluating dyspnea, fatigue, emotional function, and mastery. Side effects were relatively infrequent and generally mild for both study drugs. These results show that ipratropium bromide, given by nebulization, is safe and effective in the outpatient treatment of COPD.
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PMID:Nebulized bronchodilators for outpatient management of stable chronic obstructive pulmonary disease. 861 Jul 12

Recently, it was suggested that fatigue of peripheral muscles could contribute to exercise limitation in patients with chronic obstructive pulmonary disease (COPD). In order to quantify the role of peripheral muscle force, we restudied potential determinants of exercise capacity (6-min walking distance [6 MWD] and maximal oxygen consumption [V02max]) in 41 consecutive COPD patients (FEV1, 43 +/- 19% of predicted, TLCO, 56 +/- 25% of predicted) admitted to our pulmonary rehabilitation program. VO2max (incremental cycle ergometer test), 6 MWD (best of three), lung function (FEV1, FVC, TLC, FRC), diffusing capacity (TLCO), isometric quadriceps force (QF), hand grip force (HF), and maximal inspiratory (PImax) and expiratory (PEmax) pressures were measured. Patients had a poor 6 MWD (372 +/- 136 m) and VO2max (1.35 +/- 0.60 L, 71%), reduced respiratory (PImax 65 +/- 27%) and peripheral muscle force (QF 74 +/- 27%, HF 82 +/- 23%). In single regression analysis, significant correlations (r) were found for VO2max and TLCO (0.68), FEV1 (0.64), QF (0.55), HF (0.53), and body weight (0.49). Walking distance was significantly correlated with QF (0.63), HF (0.61), PImax (0.49), and TLCO (0.38). In stepwise multiple regression analysis, the variables significantly contributing to 6 MWD were QF and Plmax. For VO2max, variables significantly contributing were TLCO, QF, and FEV1. We conclude that lung function and peripheral muscle force are important determinants of exercise capacity in COPD.
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PMID:Peripheral muscle weakness contributes to exercise limitation in COPD. 863 May 82

To help clinicians better assess and treat functional disabilities in persons with acquired immunodeficiency syndrome (AIDS), the authors estimate empirical relations among biologic and physiologic variables, symptoms, and physical functioning in persons with AIDS. The sample of 305 persons with AIDS for this cross-sectional analysis came from three sites in Boston, Massachusetts: a hospital-based group practice, a human immunodeficiency virus clinic at a city hospital, and a staff-model health maintenance organization. Physical functioning, 10 AIDS-specific symptoms, and mental health were assessed by interview. Clinical diagnoses, comorbidities, health habits such as smoking, laboratory results, and selected medication use were assessed by chart review. Significant predictors of physical functioning P < 0.01, R2 = .58) in a multivariable regression model included energy/fatigue, neurologic symptoms, fever symptoms, a lower hemoglobin level, and current non-pneumonia bacterial infection. Ninety-six percent of the explained variance in physical functioning was accounted for by three symptom complexes: energy/fatigue, neurologic symptoms, and fever symptoms. Significant predictors of energy/fatigue in multivariable models included poorer mental health, lower white blood cell count, longer time since diagnosis, and weight loss (P < 0.01, R2 =.36). Significant predictors of neurologic symptoms included poorer mental health, weight loss, and no zidovudine use (P < 0.001, R2 = .30). Predictors of fever symptoms included poorer mental health, no zidovudine use, weight loss, and history of asthma or chronic obstructive pulmonary disease (P < 0.05, R2 = .25). In conclusion, symptom reports were strong predictors of physical functioning. Poorer mental health and weight loss were correlated consistently with worse symptoms, and not using zidovudine was correlated with worse neurologic and fever symptoms. These variables, and the others the authors identified, may represent mutable determinants of physical functioning in persons with AIDS, and potential targets for specific clinical interventions.
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PMID:Clinical predictors of functioning in persons with acquired immunodeficiency syndrome. 865 26

The chest and abdomen impedance respirographs (IRG), including the one dimensional IRG and the two dimensional IRG were designed and produced by applying the principle of bioelectrical impedance. Using IRG the non-synchronized chest and abdomen respiratory motions occurring in diaphragmatic fatigue were measured. The results showed that all 203 normal controls showed synchronized style of chest and abdomen respiratory motions. In 189 COPD patients 117 (61.9%) showed non-synchronized respiratory motions which could be further divided into three types: type I showed complete contra-directional respiratory movements of chest and abdomen respiration, with M > 24 % and alpha angel > 120 degrees; type II showed staggered peak of the chest and abdomen motion curves (13% < M < 24%), 50 degrees < alpha angle < 120 degrees; type III showed double peaks of abdomen trace in the one dimensional IRG and "8"-shaped double circles on the two dimensional IRG, (M < 13%, 50 degrees < alpha angle < 120 degrees. When compared with trans-diaphragmatic pressure (Pdi) and diaphragm myoelectricity frequency spectrum, the rates of conformity were 81.8% and 90%, respectively, suggesting that IRG could be reliably used for diagnosing diaphragmatic fatigue. This technique is simple, easy to use, cheap and pain-free.
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PMID:Application of electrical impedance principle in the diagnosis of diaphragm fatigue. 873 30


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