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

We designed and performed the chest and abdomen impedance respirograph (IRG), which included the one dimentional IRG and the two dimentional IRG, by applying the principle of bioelectrical impedance. Using IRG, we measured the non-synchronized chest and abdomen respiratory motions occurring in the diaphragmatic fatigue. The results showed that all 203 normal control subjects showed synchronized pattern 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 contradirectional movements of respiration, M > 24% and alpha angle > 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 in the one dimentional IRG and 8-shaped double circles in the two dimentional IRG, M < 13%, alpha angle > 40 degrees. When compared with Pdi and diaphragm myoelectricity frequency spectrum the rates of accordance were 81.8% and 90%, respectivity, suggesting that IRG could be reliably used to diagnose diaphragmatic fatigue. This technique is simple, easy, cheap and non-invasive. It is, therefore, worth to be widely recommanded for clinical investigation.
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PMID:[Investigation of the application of electrical impedance principle for the diagnosis of diaphragm fatigue]. 876 84

Prior studies demonstrate the ability of upper extremity training to increase arm strength and endurance when incorporated into a pulmonary rehabilitation program. However, patients with severe chronic obstructive pulmonary disease (COPD) may have transportation or mobility problems that make it difficult to travel to a rehabilitation site to obtain this training. This pilot study was designed to determine whether a home-based, upper-arm exercise program could increase arm strength and endurance, and decrease perceptions of breathlessness and fatigue during five activities of daily living. Twenty patients with severe COPD (FEV1 0.80 +/- 0.42) were randomized to an experimental (n = 10) or control group (n = 10). The experimental-group training included three upper arm exercises five times a week for 8 weeks, with training level incremented during weekly home visits. Control-group subjects were contacted weekly to equalize attention from health care providers. During the upper-extremity endurance test for number of rings moved, no significant differences between groups were seen for interaction or treatment. However, there was a significant interaction between treatment and time for perceived fatigue (p = 0.0012), with the experimental group perceiving less fatigue during upper arm work than did the control group. No change was seen in perceived breathlessness. Findings of this study suggest that a home-based, upper-arm exercise program can reduce perceptions of fatigue for patients with severe COPD during activities involving upper arm work. Testing in a larger sample is indicated to determine whether this training can also improve ability to perform unsupported arm work.
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PMID:Home-based, upper-arm exercise training for patients with chronic obstructive pulmonary disease. 883 44

Respiratory muscle (RM) dysfunction is a progressive process, including both RM weakness and fatigue, that may advance to the point of respiratory failure. It occurs as a result of increased RM workloads, altered length-tension relationship of respiratory muscles, malnourished states, and altered cellular environment in chronic obstructive pulmonary disease (COPD). Consideration of multiple patient factors is necessary when identifying patient risk for RM dysfunction and designing plans of care. This article discusses the RM pump, including its measurement, in patients with COPD.
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PMID:Respiratory muscle function in patients with chronic obstructive pulmonary disease. 883 43

Weaning failure is, unfortunately, a rather common phenomenon for mechanically-ventilated patients (especially those with chronic obstructive pulmonary disease (COPD)), and the respiratory muscles play a pivotal role in its development. Weaning fails whenever an imbalance exists between the ventilatory needs and the neurocardiorespiratory capacity. This can happen if there is an increase in the energy demands of the respiratory muscles, a decrease in the energy available, a decrease in neuromuscular competence, or if the respiratory muscles pose an impediment to the heart and blood flow. The imbalance created will lead to weaning failure through the development of respiratory muscle fatigue, hypercapnia, dyspnoea, anxiety and organ dysfunction.
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PMID:Respiratory muscles and weaning failure. 894 90

In normal subjects 2 min of maximal voluntary hyperventilation results in failure of tension generation and low-frequency fatigue of the diaphragm. Patients with severe chronic obstructive pulmonary disease (COPD) do not develop diaphragm fatigue during exhaustive treadmill exercise despite excessive inspiratory muscle loading and we hypothesized that they might be relatively resistant to the development of diaphragm fatigue during maximal ventilation. In six patients with severe COPD (mean FEV1 0.671) we therefore loaded the diaphragm using 2 min of maximal isocapnic ventilation (MIV). Initial mean ventilation was 28.6 L/min and diaphragm pressure-time product (PTPdi) 602 cm H2O x s/min; these values were sustained throughout MIV without significant decline. Mean twitch transdiaphragmatic pressure (Tw Pdi) was 19.7 cm H2O 25 min after a control run and 20.5 cm H2O at the same time after MIV [corrected]. Compared with normal subjects previously studied in our laboratory (Hamnegard, C.-H., et al. Eur. Respir. J. 1996;9:241-247) the reduction in PTPdi was disproportionately greater than the reduction in Tw Pdi. We conclude that, unlike normal subjects, 2 min of MIV causes neither failure of diaphragm performance nor low-frequency diaphragm fatigue in patients with severe COPD. It is likely that the diaphragm makes a relatively limited contribution to the generation of maximal levels of ventilation in severe COPD.
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PMID:Diaphragm performance during maximal voluntary ventilation in chronic obstructive pulmonary disease. 903 7

The influence of the resistive load on the phase difference (PD) between chest wall and mouth flow in patients with chronic obstructive pulmonary disease (COPD) was investigated, and the factors that induce an enlargement of the PD were assessed. After a resistance tube (R = 2.8 hPa/l/s) was applied to the mouth of the subjects, the PDs increased significantly both in normal (pre: 2.20 +/- 0.89, post: 5.60 +/- 2.04, P < 0.01) and in COPD (pre: 10.86 +/- 3.81; post: 13.12 +/- 3.64, P < 0.01). A significant correlation between the airway resistance and PD was noted (r = 0.730, P < 0.001). These results suggest that airway resistance is an important determinant for the PD. The predicted phase difference (PD') was then calculated by the Runge-Kutta method, using the measured chest flow, the time domain functions of airway resistance and the thoracic gas volume during a respiratory cycle, assuming that the respiratory system was a single compartment. The PD/PD' at pre-resistive load was significantly larger in COPD than in normal subjects (normal: 1.03 +/- 0.11; COPD, 1.45 +/- 0.19, P < 0.01), whereas the PD/PD' at a post-resistive load was significantly smaller than at the pre-resistive load in COPD patients. These results agree well with the two parallel or serial compartment model with inhomogeneous airway resistance, where the mechanical property of the partitioning tissue between the two compartments was taken into account. The pattern of the increase in the work energy consumed within the airway lumen calculated from this model was almost the same as for PD. Thus, we conclude that the PD may be a good index of the overload of the respiratory movement and available to predict muscle fatigue in COPD patients.
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PMID:Effects of resistive load on the phase difference between chest and mouth flow in patients with chronic obstructive pulmonary disease. 908 97

Patients with severe chronic obstructive pulmonary disease (COPD) have a greater neural drive to the parasternal intercostal and scalene muscles and greater inspiratory expansion of the rib cage than do healthy individuals. However, such patients also have a reduced outward displacement or a paradoxical inward displacement of the ventral abdominal wall during inspiration. This has led to the suggestion that they may have less use of the diaphragm, possibly secondary to chronic muscle fatigue. To assess the effect of COPD on the neural drive to the diaphragm, we inserted needle electrodes into the costal part of the right hemidiaphragm in eight patients with severe disease (mean [+/- SD] FEV1: 0.82 [+/- 0.27] L) and six control subjects of similar age, and measured the discharge frequencies of single motor units during resting breathing. A total of 115 diaphragmatic motor units were recorded in the control subjects and 122 in the patients. All motor units discharged rhythmically in phase with inspiration. However, whereas 95% of the units in the control subjects had a peak discharge frequency between 7 and 14 Hz, 79% of the units in the COPD patients had a peak discharge frequency greater than 15 Hz. As a result, the discharge frequency of all units averaged 10.5 [+/- 2.4] Hz in the control subjects, but 17.9 [+/- 4.3] Hz in the patients (p < 0.001). These observations indicate that patients with severe COPD have an increased neural drive not only to the rib cage inspiratory muscles, but also to the diaphragm. Consequently, the reduced inspiratory expansion of the abdomen in severe COPD results from mechanical factors alone.
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PMID:Neural drive to the diaphragm in patients with severe COPD. 910 76

To clarify the demographic and clinicolaboratory features of postdialysis fatigue (PDF), we enrolled 85 patients on maintenance hemodialysis in a cross-sectional study using validated questionnaires and chart review. Forty-three patients complained of fatigue after dialysis. On formal testing using the Kidney Disease Questionnaire, the PDF group had statistically greater severity of fatigue and somatic complaints than the group of patients without subjective fatigue (P = 0.03 and 0.04, respectively). On a scale measuring intensity of fatigue (1 = least to 5 = worst), the PDF group average was 3.4 +/- 1.2. PDF subjects reported that 80% +/- 25% of dialysis treatments were followed by fatigue symptoms. In 28 (65%) of patients, the symptoms started with the first dialysis treatment. They reported needing an average of 4.8 hours of rest or sleep to overcome the fatigue symptoms (range, 0 to 24 hours). There were no significant differences between patients with and without PDF in the following parameters: age; sex; type of renal disease; presence of diabetes mellitus, heart disease (congestive, ischemic), or chronic obstructive lung disease; blood pressure response to dialysis; type or adequacy of dialysis regimen; hematocrit; electrolytes; blood urea nitrogen; creatinine; cholesterol; albumin; parathyroid hormone; ejection fraction; and use of antihistamines, benzodiazepines, and narcotics. In the fatigue group, there was significantly greater use of antihypertensive medications known to have fatigue as a side effect (P = 0.007). Depression was more common in the fatigue group by Beck Depression score (11.6 +/- 8.0 v 7.8 +/- 6.3; P = 0.02). We conclude that (1) postdialysis fatigue is a common, often incapacitating symptom in patients on chronic extracorporeal dialysis; (2) no routinely measured parameter of clinical or dialytic function appears to predict postdialysis fatigue; and (3) depression is highly associated with postdialysis fatigue, but the cause-effect relationship is unclear.
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PMID:Postdialysis fatigue. 915 12

Mechanical ventilation via a tracheal tube is an invasive measure whose complications may prevent recovery from respiratory failure. Today, noninvasive positive pressure ventilation via mouthpiece or mask is an economically and medically successful alternative for the treatment of chronic respiratory failure and acute exacerbation of COPD, respectively. Within certain limits, noninvasive ventilation may take over inspiratory work of breathing as well as elevate mean airway pressure and inspiratory oxygen concentration. This does not at all question the absolute indications to maintain a patent airway by tracheal intubation. Clinical applications of noninvasive ventilation within these limits are acute exacerbation of COPD, congestive heart failure with pulmonary edema or atelectasis. Respiratory muscle fatigue, cardiogenic and septic shock, severe pneumonia and ARDS are still absolute indications for invasive ventilation. Table 1 specifies 12 disadvantages and endpoints of noninvasive mechanical ventilation.
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PMID:[Contra: noninvasive ventilation in acute respiratory insufficiency]. 923 64

There is no disease-specific instrument available for health status assessment in bronchiectasis. We examined the stability, validity and responsiveness of a measure designed for asthma and COPD, the St. George's Respiratory Questionnaire (SGRQ), in this condition. One hundred and eleven patients were studied on 2 separate d 6 mo apart. On both days each patient completed the SGRQ and measures of general and disease-specific health, mood, and fatigue. They also performed a shuttle walking test and comprehensive lung function tests. Repeatability was tested over 2 wk in 23 patients. The intraclass correlation (ri) for the SGRQ Total score was 0.97. The SGRQ component scores correlated well with relevant markers of disease activity. Examples include: SGRQ Symptoms score versus MRC Wheeze score, r = 0.634, p < 0.0001; Activity score versus shuttle walking test, r = -0.659, p < 0.0001; and impacts score versus physical fatigue, r = 0.610, p < 0.0001. Changes in the SGRQ Total score from entry to follow-up also correlated with changes in other measures of the patients' health. There were significant differences in the SGRQ total score between patients who improved and those who deteriorated over the 6 mo in respect to wheeze (F = 5.6, p < 0.01) and breathlessness (F = 6.05, p < 0.01). We conclude that the SGRQ reflects impaired health in bronchiectasis patients.
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PMID:Validation of the St. George's Respiratory Questionnaire in bronchiectasis. 927 36


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