CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 8 2004
DG Allen
SUMMARY 1.,Repeated activity of skeletal muscle causes a variety of changes in its properties: muscles become weaker with intense use (fatigue), may feel sore and weak after repeated contractions involving stretch and can degenerate in some disease conditions. The present review considers the role of early ionic changes in the development of each of these conditions. 2.,Single fibre preparations of mouse muscle were used to measure ionic changes following activity induced changes in function. Single fibres were dissected with intact tendons and stimulated to produce force. Fluorescent indicators were microinjected into the fibres to allow simultaneous ionic measurements with determination of mechanical performance. 3.,One theory to explain muscle fatigue is that fatigue is caused by the accumulation of lactic acid, producing an intracellular acidosis that inhibits the myofibrillar proteins. In contrast, we found that during repeated tetani there was little or no pH change, but that failure of calcium release was a major contributor to fatigue. Currently, it is proposed that precipitation of calcium and phosphate in the sarcoplasmic reticulum contributes to the failure of calcium release. 4.,Muscles can be used to shorten and produce force or they can be used to de-accelerate loads (stretched or eccentric contractions). One day after intense exercise involving stretched contractions, muscles are weak, sore and tender, and this damage can take a week to recover. In this condition, sarcomeres are disorganized and there are increases in resting intracellular Ca2+ and Na+. Recently, we demonstrated that the elevation of Na+ occurs through a stretch-activated channel that can be blocked by either gadolinium or streptomycin. Preventing the increase in [Na+]i with gadolinium also prevented part of the muscle weakness after stretched contractions. 5.,Duchenne muscular dystrophy is a lethal degenerative disease of muscles in which the protein dystrophin is absent. Dystrophic muscles are more susceptible to stretch-induced muscle damage and the stretch-activated channel seems to be one pathway for the increases in intracellular Ca2+ and Na+ that are a feature of this disease. We have shown recently that blockers of the stretch-activated channel can minimize some of the short-term damage in muscles from the mdx mouse, which also lacks dystrophin. Currently, we are testing whether blockers of the stretch-activated channels given systemically to mdx mice can protect against some features of the disease. [source]

The incidence of anxiety and depression among employees,the role of psychosocial work characteristics

DEPRESSION AND ANXIETY, Issue 11 2009
Helene Andrea Ph.D.
Abstract Background: Anxiety and depression are prevalent among employees and are associated with functional disability and work impairment. To date, little is known about the incidence and possible risk factors for developing anxiety and depression in the working population. Study aims were to (a) determine the incidence of subclinical anxiety and depression in a general working population and (b) identify the psychosocial work characteristics associated with the onset of subclinical anxiety and depression. Methods: This prospective study is based on 3,707 employees participating in the Maastricht Cohort Study on Fatigue at Work. Psychosocial work characteristics were measured in May 2000; anxiety and depression were measured with the Hospital Anxiety and Depression Scale in April 2002. Results: The cumulative 23-month incidence for subclinical anxiety and depression was 4.6 and 3.3%, respectively. High psychological job demands increased the risk for both subsequent anxiety and depression. Moreover, low social support was predictive for the onset of anxiety, whereas job insecurity increased the risk for the onset of depression. These prospective associations were independent of potential confounding variables and the other psychosocial work characteristics. Conclusions: Adverse psychosocial work characteristics are significant predictors for the onset of subclinical anxiety and depression in the general working population. These findings encourage intervention studies testing whether modifying the psychosocial work environment reduces both anxiety and depressive symptoms among employees. Depression and Anxiety 26:1040,1048, 2009. © 2009 Wiley-Liss, Inc. [source]

Rescuer Fatigue: Standard versus Continuous Chest-Compression Cardiopulmonary Resuscitation

ACADEMIC EMERGENCY MEDICINE, Issue 10 2006
Joseph W. Heidenreich MD
Abstract Objectives Continuous chest-compression cardiopulmonary resuscitation (CCC-CPR) has been advocated as an alternative to standard CPR (STD-CPR). Studies have shown that CCC-CPR delivers substantially more chest compressions per minute and is easier to remember and perform than STD-CPR. One concern regarding CCC-CPR is that the rescuer may fatigue and be unable to maintain adequate compression rate or depth throughout an average emergency medical services response time. The specific aim of this study was to compare the effects of fatigue on the performance of CCC-CPR and STD-CPR on a manikin model. Methods This was a prospective, randomized crossover study involving 53 medical students performing CCC-CPR and STD-CPR on a manikin model. Students were randomized to their initial CPR group and then performed the other type of CPR after a period of at least two days. Students were evaluated on their performance of 9 minutes of CPR for each method. The primary endpoint was the number of adequate chest compressions (at least 38 mm of compression depth) delivered per minute during each of the 9 minutes. The secondary endpoints were total compressions, compression rate, and the number of breaks taken for rest. The students' performance was evaluated on the basis of Skillreporter Resusci Anne (Laerdal, Wappingers Falls, NY) recordings. Primary and secondary endpoints were analyzed by using the generalized linear mixed model for counting data. Results In the first 2 minutes, participants delivered significantly more adequate compressions per minute with CCC-CPR than STD-CPR, (47 vs. 32, p = 0.004 in the 1st minute and 39 vs. 29, p = 0.04 in the 2nd minute). For minutes 3 through 9, the differences in number of adequate compressions between groups were not significant. Evaluating the 9 minutes of CPR as a whole, there were significantly more adequate compressions in CCC-CPR vs. STD-CPR (p = 0.0003). Although the number of adequate compressions per minute declined over time in both groups, the rate of decline was significantly greater in CCC-CPR compared with STD-CPR (p = 0.0003). The mean number of total compressions delivered in the first minute was significantly greater with CCC-CPR than STD-CPR (105 per minute vs. 58 per minute, p < 0.001) and did not change over 9 minutes in either group. There were no differences in compression rates or number of breaks between groups. Conclusions CCC-CPR resulted in more adequate compressions per minute than STD-CPR for the first 2 minutes of CPR. However, the difference diminished after 3 minutes, presumably as a result of greater rescuer fatigue with CCC-CPR. Overall, CCC-CPR resulted in more total compressions per minute than STD-CPR during the entire 9 minutes of resuscitation. [source]

Fatigue and processing speed are related in multiple sclerosis

EUROPEAN JOURNAL OF NEUROLOGY, Issue 2 2010
A. K. Andreasen
Background:, Fatigue is common in multiple sclerosis (MS) and could be related to impaired processing speed caused by MS specific brain alterations. The objective of this study was to examine the relationship between processing speed and fatigue in patients with relapsing remitting MS. Methods:, Patients with EDSS score ,3.5 were grouped as fatigued [Fatigue Severity Scale (FSS) score ,5.0] or non-fatigued (FSS score ,4.0). Patients with FSS scores ,5 were categorized as primary or secondary fatigued according to various indices. A cognitive test battery obtained from Wechsler's Adult Intelligence Scale-III/Wechsler's Memory Scale-III was applied. Results:, Processing speed (Digit Symbol Coding) was lower amongst all MS patients being 9.4(2.9) in primary fatigued, 8.3(2.8) in secondary fatigued and 10.3(2.7) in non-fatigued versus 12.3(3.0) in healthy controls. In the combined group of primary and secondary fatigued MS patients, processing speed was slower than that in non-fatigued MS patients and inversely related to fatigue (r = ,0.35; P < 0.05). No such relationship could be established in non-fatigued MS patients or in healthy controls. Conclusion:, The degree of fatigue in MS is related to processing speed impairment and longitudinal studies should clarify their mutual dependency. [source]

Measuring fatigue in patients with Parkinson's disease , the Fatigue Severity Scale

EUROPEAN JOURNAL OF NEUROLOGY, Issue 6 2002
K. Herlofson
The objective was to compare the prevalence and severity of fatigue in patients with Parkinson's disease (PD) with that in two control groups, one consisting of randomly chosen control subjects of the same age and sex distribution and the other consisting of patients with coxarthrosis waiting to receive total hip replacement. We also explored the possible correlation of demographic and clinical data to the presence and severity of fatigue. Sixty-six patients with PD, 131 randomly chosen controls and 79 patients with coxarthrosis, waiting to receive total hip replacement, were evaluated for fatigue. Patients and controls with a depressive mood disorder or cognitive impairment had been excluded from the study. Fatigue was measured by the Fatigue Severity Scale (FSS). For the patients with PD the mean total FSS score was 4.1, compared with 2.7 amongst the randomly chosen control group and 2.9 in the group consisting of patients with coxarthrosis. Fifty per cent of the patients with PD had a mean total FSS score of 4 or higher, compared with 25% in both of the two control groups. There was no correlation between pain, presence of self-reported nocturnal sleep disorders or duration of PD and fatigue. The patients with fatigue did have a more advanced disease, measured both by Unified Parkinson's Disease Rating Scale score and Hoehn and Yahr stage. Although the univariate analyses indicated that more severe parkinsonism was correlated to the symptom, the multivariate analysis showed that none of the studied variables were significant explanatory factors for fatigue. Fatigue is a common symptom in patients with PD without depression or dementia. The study indicates that fatigue is an independent symptom of the disease without relation to other motor or non-motor symptoms. [source]

Special Topics: DGM/DVM Working Group Materials Fatigue

ADVANCED ENGINEERING MATERIALS, Issue 4 2010
Article first published online: 23 APR 2010
No abstract is available for this article. [source]

Fatigue of Alumina Under Cyclic Torsion Loading,

ADVANCED ENGINEERING MATERIALS, Issue 7 2009
Thomas Schwind
The work investigates the cyclic fatigue behavior of alumina. It reveals that for cyclic torsion tests the maximum stress criterion is not valid. Cyclic torsion loading leads to a reduced lifetime compared to cyclic tensile-compression. Also an increased cyclic fatigue effect compared to four point bending tests was revealed. [source]

Fatigue of Metal Hollow Spheres Structures,

ADVANCED ENGINEERING MATERIALS, Issue 3 2008
O. Caty
Fatigue properties of three kinds of hollow metal spheres structures were determined in compression/compression. These results were completed with a fatigue damage process study by ex-situ X-ray tomography and a finite element simulation using tomographic 3D images. All these data permitted to understand the chronology of damage in the structure. The difference in behaviour of the three kinds of materials is mainly explained by the process root used (brazing and sintering) and by the nature of the constitutive material. [source]

Contractile Properties, Fatigue and Recovery are not Influenced by Short-Term Creatine Supplementation in Human Muscle

EXPERIMENTAL PHYSIOLOGY, Issue 4 2000
J. M. Jakobi
There have been several studies on the effect of short-term creatine (Cr) supplementation on exercise performance, but none have investigated both voluntary and stimulated muscle contractions in the same experiment. Fourteen moderately active young men (19-28 years) were randomly assigned, in a double blind manner, to either a creatine (Cr) or placebo (P) group. The subjects supplemented their regular diet 4 times a day for 5 days with either 5 g Cr + 5 g maltodextrin (Cr group), or 5 g maltodextrin (P group). Isometric maximal voluntary contraction (MVC), muscle activation, as assessed using the modified twitch interpolation technique, electrically stimulated contractile properties, electromyography (EMG), endurance time and recovery from fatigue were measured in the elbow flexors. The fatigue protocol involved both voluntary and stimulated contractions. Following supplementation there was a significant weight gain in the Cr group (1.0 kg), whereas the P group did not change. For each group, pre-supplementation measures were not significantly different from post-supplementation for MVC, twitch and tetanic tensions at rest, time to peak tension, half-relaxation time and contraction duration. Prior to Cr supplementation time to fatigue was 10 ± 4 min (mean ± S.E.M.) for both groups, and following supplementation there was a non-significant increase of 1 min in each group. MVC force, muscle activation, EMG, stimulated tensions and durations were similar for the Cr and P groups over the course of the fatigue protocol and did not change after supplementation. Furthermore, recovery of MVC, stimulated tensions and contractile speeds did not differ as a result of Cr supplementation. These results indicate that short-term Cr supplementation does not influence isometric elbow flexion force, muscle activation, stimulated contractile properties, or delay time to fatigue or improve recovery. [source]

A generalized frequency separation,strain energy damage function model for low cycle fatigue,creep life prediction

FATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 4 2010
S.-P. ZHU
ABSTRACT Fatigue,creep interaction is a key factor for the failures of many engineering components and structures under high temperature and cyclic loading. These fatigue,creep life prediction issues are significant in selection, design and safety assessments of those components. Based on the frequency-modified Manson,Coffin equation and Ostergren's model, a new model for high temperature low cycle fatigue (HTLCF), a generalized frequency separation,strain energy damage function model is developed. The approach used in this model to reflect the effects of time-dependent damaging mechanisms on HTLCF life is different from those used in all the earlier models. A new strain energy damage function is used to reduce the difference between the approximate strain energy and real strain energy absorbed during the damage process. This proposed model can describe the effects of different time-dependent damaging mechanisms on HTLCF life more accurately than others. Comparing traditional frequency separation technique (FS) and strain energy frequency-modified approach (SEFS), the proposed model is widely applicable and more precise in predicting the life of fatigue,creep interaction. Experimental data from existing literature are used to demonstrate the feasibility and applicability of the proposed model. A good agreement is found between the predicted results and experimental data. [source]

The influence of the environment and corrosion on the structural integrity of aircraft materials

FATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 6 2009
S. RUSSO
ABSTRACT Fatigue results of 11/2 dog-bone jointed specimens manufactured from 7075-T6 aluminium alloy indicated that the application of corrosion preventative compounds (CPCs) at the faying surfaces slightly decreased the log mean fatigue life at 144 MPa, while the effect was not statistically significant at the higher stress level (210 MPa). The addition of the CPC also reduced fretting corrosion at the faying surfaces and shifted the fatigue initiation sites closer to the edge of fastener holes. Scatter in fatigue life was found to be associated with the location and size of the intermetallics at the initiation site. The presence of corrosion in the bores of the countersunk fastener holes reduced the fatigue life by up to one order of magnitude. Fatigue test results for dog-bone specimens manufactured from 7075-T651 and 2024-T351 aluminium alloys indicated that the presence of exfoliation corrosion reduced the fatigue life under dry conditions, with a greater reduction under humid conditions. The application of a CPC to the corroded region eliminated the influence humidity had on fatigue life. [source]

Thirty years on from the paper ,Gust Spectrum Fatigue Crack Propagation in Candidate Skin Materials', Fatigue of Engineering Materials and Structures, Vol.

FATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 1 2009

IMPACT OF THE PAPER This paper1 addressed a very specific topic and by itself would not have had much impact in the intervening years. However, most of the paper's content was subsequently included in an extensive report on the Damage Tolerance (DT) properties of aluminium alloys.2 This report enabled guidelines for flight simulation fatigue crack growth testing to be formulated.3,4 [source]

Fatigue of shot peened 7075-T7351 SENB specimen , A 3-D analysis

FATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 6 2006
T. HONDA
ABSTRACT As-received or shot peened 7075-T7351 single-edged notch bend (SENB) specimens, 8.1-mm thick, were fatigued at a constant maximum load and at stress ratios of R= 0.1 and 0.8 to predetermined numbers of fatigue cycles or to failure. The SENB specimens were then fractured by overload and the tunnelling crack profiles were recorded. The crack-growth rate, da/dN, after crack initiation at the notch was determined by crack-profile measurement and fractography at various fatigue cycles. The shot peened surface topography and roughness was also evaluated by three-dimensional (3-D) laser scanning microscopy. Residual stresses in the as-received specimens and those generated by shot peening at Almen scales of 0.004A, 0.008A, 0.012A and 0.016A, were measured by an X-ray diffraction stress analyser with an X-ray target, CrK, every 0.1 mm to a depth of 1 mm. The 3-D stress intensity factor of the curved crack front was determined by the superposition of the 3-D finite element solutions of the stress intensity factor of the loaded SENB specimen without the residual stress and the stress intensity factor of the unloaded SENB specimen with a prescribed residual stress distribution. da/dN versus the resultant stress intensity factor amplitude, ,KI, plots showed that while the residual stress locally retarded the crack-growth rate it had no effect on the overall crack-propagation rate. [source]

Fatigue as a process of cyclic brittle microfracture

FATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 3 2005
R. SUNDER
ABSTRACT While fatigue crack growth in vacuum may occur by slip alone, environmental fatigue including crack growth in air is strongly influenced by crack-tip surface chemistry that adversely affects ductility. Cumulative diffusion, combined with adsorption and chemisorption in the loading half-cycle may promote instantaneous crack extension by brittle microfracture (BMF). Unlike slip, the BMF component will be sensitive to parameters that affect near-tip stresses, such as load history and constraint. BMF dominates near-threshold environmental fatigue. Being a surface phenomenon, it loses its significance with increasing growth rate, as slip-driven crack extension gains momentum and growth becomes less sensitive to environment. The BMF model provides for the first time, a scientific rationale for the residual stress effect as well as the related connection between stress,strain hysteresis and load-sequence sensitivity of metal fatigue including notch response. Experimental evidence obtained on a variety of materials under different loading conditions in air and vacuum appears to support the proposed model and its implications. [source]

Fatigue of cantilevered pipe fittings subjected to vibration

FATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 8 2003
M. HAMBLIN
ABSTRACT Vibration fatigue failures in piping systems often occur at cantilevered small-bore fittings (SBF) such as pressure tappings and drain valves. Piping vibration has often been assessed by measuring vibration displacement or velocity. However, in the case of straight cantilevered fittings with a concentrated mass, a better method exists. This paper presents a simple robust method of calculating vibration induced stress for cantilevered fittings at both the fitting branch neck and the main pipe. The method is based on measurement of acceleration at the concentrated mass (e.g., valve) and simple mechanics calculations. Extensive laboratory and field verification of the technique is presented. The choices of a fatigue strength criterion, such as ASME BPVC VIII Div. 2, BS7608, or a fracture mechanics approach such as BSI PD6493, are discussed. Several case studies are presented as well as simple ,good engineering practice' rules-of-thumb for SBF design. These ,rules-of-thumb' are now incorporated in the piping specifications of the author's company. [source]

Special double issue on the International Conference ,Fatigue in the Very High Cycle Regime', held in Vienna on 2,4 July 2001

FATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 8-9 2002
Stefanie Stanzl-Tschegg
No abstract is available for this article. [source]

The validation of some methods of notch fatigue analysis

FATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 5 2000
Taylor
This paper is concerned with the testing and validation of certain methods of notch analysis which the authors have developed theoretically in earlier publications. These methods were developed for use with finite element (FE) analysis in order to predict the fatigue limits of components containing stress concentrations. In the present work we tested and compared these methods using data from standard notches taken from the literature, covering a range of notch geometries, loading types, R -ratios and materials: a total of 47 different data sets were analysed. The greatest predictive success was achieved with critical-distance methods known as the point, line and area methods: 94% of these predictions fell within 20% of the experimental fatigue limits. This was a significant improvement on previous methods of this kind, e.g. that of Klesnil and Lucas [(1980) Fatigue of Metallic Materials, Elsevier Science]. Methods based on the Smith and Miller [(1978) Int. J. Mech. Sci. 20, 201,206] concept of crack-like notches were successful in 42% of cases; they experienced difficulties dealing with very small notches, and could be improved by using an ElHaddad-type correction factor, giving 87% success. An approach known as ,crack modelling' allowed the Smith and Miller method to be used with non-standard stress concentrations, where notch geometry is ill defined; this modification, with the same short-crack correction, had 68% success. It was concluded that the critical-distance approach is more accurate and can be more easily used to analyse components of complex shape, however, the crack modelling approach is sometimes preferable because it can be used with less mesh refinement. [source]

Nocturnal Hemodialysis Is Better Than Quotidian Hemodialysis

HEMODIALYSIS INTERNATIONAL, Issue 1 2003
MP Kooistra
Background. It is unknown whether long nocturnal (6,7 times weekly 6,8 hours) hemodialysis (NHD) is better than frequent short hemodialysis (,daily', quotidian hemodialysis, QHD). Methods. A Dutch NHD pilot study (,Nocturne') started in December 2001. We can now evaluate effects of 4 months NHD in 14 patients. Baseline dialysis frequency was 3.5 or less (3.13 ± 0.23, M ± SD) in group A (n = 8), and 4 or more (5.0 ± 0.89) in group B (n = 6), weekly dialysis time was equal in both groups. Results. Single pool Kt/V, being higher in group B at baseline, increased in both groups (A: 3.1 ± 0.8/week to 9.5 ± 2.3, B: 3.8 ± 1.0 to 10.9 ± 4.1). Baseline nPCR, being higher in group B, increased in both groups (A: 1.0 ± 0.3 g/kg/week to 1.4 ± 0.3, and B: 1.2 ± 0.5 to 1.8 ± 0.5). Baseline albumin was higher in group B, and increased in group A (39.6 ± 3.7 g/l to 43.2 ± 1.5), not in B (41.4 ± 2.3 to 42.8 ± 2.3). Target weight increased only in group A (71.8 ± 10.5 kg to 75.3 ± 11.9), not in B (71.4 ± 25.5 to 71.3 ± 26.7). NHD resulted in normophosphatemia in both groups despite phosphate supplementation and cessation of phosphate binders. PTH decreased in both groups (A: 40.6 ± 38.0 pmol/l to 14.4 ± 11.7, B: 35.6 ± 37.7 to 22.4 ± 41.5). In both groups, pre- and postdialysis mean arterial pressure decreased (A: 106.8 ± 7.9 mmHg to 94.4 ± 12.1 and 97.3 ± 9.5 mmHg to 86.3 ± 8.2, B: 102.2 ± 28.4 to 89.4 ± 9.5 and 90.3 ± 26.8 to 82.7 ± 12.9). Antihypertensives were discontinued or markedly reduced. Fatigue, insomnia, prurigo, restlessness, appetite, physical condition, working ability and quality of life (SF36) improved significantly in both groups. Conclusion. This small pilot study suggests that phosphate and PTH control, blood pressure, uremic symptoms and quality of life improve when conventional hemodialysis or QHD patients switch to NHD. Nutritional parameters improve only in the previously conventionally treated group. [source]

The effects of HCV infection and management on health-related quality of life,

HEPATOLOGY, Issue 3 2007
Zobair Younossi
Infection with HCV leads to an array of symptoms that compromise health-related quality of life (HRQL). Chronic hepatitis C is treated primarily with pegylated interferon (peg-IFN) and an inosine 5, monophosphate dehydrogenase inhibitor, ribavirin (RBV), with the goal of achieving a sustained virologic response (SVR). SVR reduces the rate of hepatic fibrosis and other disease-related complications and, in turn, increases HRQL. Although combination therapy with peg-IFN and RBV produces SVRs in more than 50% of treated patients, it is associated with side effects that can reduce short-term HRQL, can lead to dose reductions and discontinuations, and may impair treatment response. Fatigue and depression are common symptoms of chronic HCV infection that may also be caused by IFN-based therapy. Hemolytic anemia and IFN-mediated bone marrow suppression are well-known consequences of IFN/RBV therapy, often resulting in dose reductions or discontinuations, and have the potential to affect SVR rates. Management of these symptoms is vital to successful outcomes and generally relies on therapy that is adjunctive to the primary treatment of the viral infection itself. Several new drugs with the potential to increase SVR rates without compromising HRQL are in development. Conclusion: The relationship of chronic HCV infection, treatment, and HRQL is complex. Successful treatment of chronic hepatitis C requires an understanding of the intricacies of this relationship and appropriate management of treatment-related symptoms. (HEPATOLOGY 2007;45:806,816.) [source]

Fatigue in primary biliary cirrhosis is associated with excessive daytime somnolence,

HEPATOLOGY, Issue 1 2006
Julia L. Newton
A significant proportion of patients with primary biliary cirrhosis (PBC) suffer from severe fatigue. The aim of this study was to characterize patterns of daytime sleep in patients with PBC (using both objective and subjective assessment approaches) and to study the association between sleep abnormality and fatigue severity. Fatigue severity was assessed in 48 female subjects with PBC (using a disease-specific quality of life instrument (the PBC-40) and a generic fatigue measure (Fatigue Impact Scale [FIS]) as well as 48 case-matched normal controls. All participants also completed the Pittsburgh Sleep Quality Index (PSQI) and the Epworth Sleepiness Scale (ESS, which assesses daytime hypersomnolence). Objective sleep assessment was performed using accelerometry over 7 days. Global sleep quality assessed by the PSQI was significantly lower in the PBC group compared to controls (P < .0001). ESS scores were significantly higher in patients with PBC than controls (P = .0001), suggesting significantly greater daytime somnolence in the patients with PBC. Objective sleep assessment confirmed that subjects with PBC were sleeping on average almost twice as long as controls during the daytime. Both degree of daytime somnolence (ESS) and actual daytime sleep activity (accelerometry) correlated strongly with fatigue severity in the patient group (r2 = 0.5, P < .0001 and r2 = 0.2, P < .01, respectively). In conclusion, Sleep abnormality, in the form of excessive daytime somnolence, is present in a significant proportion of patients with PBC, with the degree of daytime somnolence correlating strongly with the degree of fatigue. Existing agents effective at reducing daytime somnolence (such as modafinil) hold potential for the treatment of fatigue in PBC. (HEPATOLOGY 2006;44:91,98.) [source]

Mirtazapine and paroxetine: a drug-drug interaction study in healthy subjects

HUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 6 2001
F. J. L. Ruwe
Abstract Paroxetine inhibits cytochrome P450 2D6, which is involved in the metabolism of mirtazapine. The possible drug-drug interaction between two pharmacologically distinct antidepressants, mirtazapine and paroxetine, has been investigated in a randomized, three-way crossover study in 24 healthy male and female subjects. After a titration phase of 3 days, each subject received single daily doses of 30,mg mirtazapine, 40,mg paroxetine or the combination for 6 days. Assessments included serial blood sampling for pharmacokinetics at steady state, cognitive testing using the test battery of CDR Ltd, a visual analogue mood rating scale (Bond and Lader) and the Leeds Sleep Evaluation Questionnaire. Paroxetine inhibits the metabolism of mirtazapine, as shown by increases of approximately 17% and 25% of the 24,h AUC's of mirtazapine and its demethyl metabolite, respectively. Mirtazapine did not alter the pharmacokinetics of paroxetine. The combined administration of mirtazapine and paroxetine probably does not alter cognitive functioning or result in major changes on the visual analogue mood rating scale and Sleep Evaluation Questionnaire, compared with the administration of either drug alone. The incidence of adverse events was lower during combined administration of mirtazapine and paroxetine than during administration of either drug alone. Fatigue, dizziness, headache, nausea, anxiety and somnolence were the most common adverse events during combined administration. These data suggest that the combination of mirtazapine and paroxetine is unlikely to lead to clinically relevant drug-drug interactions and can be used without dose adjustment of either drug. The combination may even be better tolerated than either drug alone. Copyright © 2001 John Wiley & Sons, Ltd. [source]

Fatigue after myocardial infarction: Relationships with indices of emotional distress, and sociodemographic and clinical variables

INTERNATIONAL JOURNAL OF NURSING PRACTICE, Issue 4 2010
Pia Alsén RN PhD
Alsén P, Brink E, Brändström Y, Karlson BW, Persson L-O. International Journal of Nursing Practice 2010; 16: 326,334 Fatigue after myocardial infarction: Relationships with indices of emotional distress, and sociodemographic and clinical variables Fatigue and depressive symptoms are relatively common among patients recovering from myocardial infarction (MI). The symptoms of depression and fatigue overlap. The present study aimed at identifying patient fatigue and at examining the incidence of fatigue, particularly without coexisting depression, after MI. The sample comprised 204 consecutive patients who had completed the questionnaires Hospital Anxiety and Depression Scale and the Multidimensional Fatigue Inventory,20 after MI (1 week and 4 months). The results showed that fatigue had decreased after 4 months compared with the time of MI onset. Compared with the general population, patients reported significantly higher levels of fatigue. Furthermore, fatigue was associated with depression, but 33% of the sample reported fatigue without coexisting depression after 4 months. In order to prevent or treat patients' symptoms of fatigue after MI, the concepts of fatigue and depression should be assessed separately so as to exclude overlapping effects. [source]

Treatment of fatigue in multiple sclerosis: A systematic review of the literature

INTERNATIONAL JOURNAL OF NURSING PRACTICE, Issue 2 2008
David Lee PhD
Fatigue is common in people with multiple sclerosis (MS) and symptoms of fatigue are often reported as the most debilitating symptoms of the disease. However, there are few reports of interventions for fatigue in MS. A systematic review of published literature examining pharmacological and psychosocial/psychological interventions for fatigue in MS was conducted. The search and review strategy undertaken used the Centre for Reviews and Dissemination guidelines. Papers were reviewed by two independent reviewers. Of 81 studies short-listed for inclusion, 15 studies were included, of which 10 were studies of pharmacological therapy and five were studies of psychosocial/psychological interventions. Of the pharmacological studies, two were rated as of moderate-to-high quality, three of moderate quality, two of moderate-to-low quality and three of low quality. Of the psychosocial/psychological studies, three were rated as of moderate quality and two of moderate-to-low quality. None of the studies reviewed reached the highest level of quality according to pre-agreed criteria. Regardless of level of quality, effectiveness of both pharmacological and psychosocial/psychological interventions was modest at best and often absent. Accordingly, there is little evidence-based advice that can be offered to people with MS to help manage their fatigue. [source]

Sensitivity, Specificity, and Usefulness of the Dutch Fatigue Scale

INTERNATIONAL JOURNAL OF NURSING TERMINOLOGIES AND CLASSIFICATION, Issue 3 2001
Lucas J. Tiesinga PhD
Purpose. To test the sensitivity, specificity, and usefulness of the Dutch Fatigue Scale (DUFS), which is based on NANDAs defining characteristics of fatigue. Methods. A cross-sectional design was used among domiciliary patients (N = 213) with chronic heart failure (n = 138) and with breastfeeding postpartum women (n = 75). Findings. Calculations of the sensitivity and specificity of the DUFS, comparisons of the average DUFS sumscores between both nonfatigued and fatigued subjects, as well as between patients with chronic heart failure and postpartum women, and correlation coefficients performed with sociodemographic factors (age, gender, education) demonstrate acceptable psychometric properties. Conclusions. The DUFS is a reliable and valid measurement tool for the assessment of fatigue. Practice Implications. Accurate recognition of the existence and extent of fatigue must precede interventions. Easy to use, reliable tools for the bedside nurse are invaluable assets to practice. Search Terms: Fatigue, measurement of fatigue, psychometric testing [source]

A Multivariate Validation of the Defining Characteristics of Fatigue

INTERNATIONAL JOURNAL OF NURSING TERMINOLOGIES AND CLASSIFICATION, Issue 1 2001
Mei Fu MSN
PURPOSE. To validate the nursing diagnosis fatigue by providing evidence to identify, confirm, and consolidate the defining characteristics. METHODS. The Revised Piper Fatigue Scale and the Schwartz Measurement of Fatigue scales were used to collect data from four groups of healthy women (N = 182). Data were analyzed by maximum-likelihood factor analysis with varimax rotation, and major and minor defining characteristics were identified and clustered. FINDINGS. The identified defining characteristics tended to group into the dimensions identified in prior fatigue studies. Although the majority of the NANDA defining characteristics were validated, differences were found. CONCLUSIONS. atigue is a multidimensional construct. Replication of the study with a variety of samples from different geographic locations and a variety of patient populations will further cross-validate the defining characteristics of fatigue. PRACTICE IMPLICATIONS. Fatigue is a commonly experienced phenomenon in both health and illness. As the knowledge base about fatigue builds, so will the accuracy of nursing assessments and the effectiveness of nursing interventions. [source]

Fatigue in children with long-term conditions: an evolutionary concept analysis

JOURNAL OF ADVANCED NURSING, Issue 8 2009
Margaret McCabe
Abstract Title.,Fatigue in children with long-term conditions: an evolutionary concept analysis. Aim., This paper is a report of a concept analysis of fatigue in children with long-term conditions. Background., There is little research focused on the experience of fatigue in children. Previous work has focused primarily on children living with cancer. It is necessary to clarify and refine the concept, and add to the knowledge base that supports ongoing theoretical work in order to improve the clinical care of children with long-term conditions who experience fatigue. Method., English language literature published from 1989 to 2007 was searched using the CINAHL, Medline and PsychINFO data bases. Sixty-two papers and two book chapters were used in this concept analysis. Rodgers' method of evolutionary concept analysis was used. This inductive method helps us to view the concept in a sociocultural and temporal context. Findings., The number of publications focusing on fatigue in children is increasing. The analysis yielded two surrogate terms, five attributes, three antecedents and seven consequences. Based on this analysis, fatigue in children with long-term conditions appears to be a subjective experience of tiredness or exhaustion that is multidimensional and includes physical, mental, and emotional aspects. Conclusions., Evidence suggesting children with long-term conditions experience fatigue is increasing, but conceptual gaps remain. This analysis has yielded a view of fatigue in children that illustrates healthcare professionals' limited yet growing awareness of the symptom. Ongoing study as a means to refine our understanding of the concept could potentially lead to important contributions to clinical care of children with long-term conditions. [source]

Fatigue in patients with rheumatoid arthritis: British and Dutch nurses' knowledge, attitudes and management

JOURNAL OF ADVANCED NURSING, Issue 4 2009
Han Repping-Wuts
Abstract Title.,Fatigue in patients with rheumatoid arthritis: British and Dutch nurses' knowledge, attitudes and management. Aim., This paper is a report of a study conducted to compare the knowledge, attitudes and current management of rheumatoid arthritis-related fatigue in British and Dutch rheumatology nurses. Background., After pain, fatigue is the most important symptom for patients with rheumatoid arthritis, but little is known about the current management of this fatigue by healthcare professionals. Methods., A questionnaire was mailed in 2007 to rheumatology nurses who were members of British Health Professionals in Rheumatology (N = 267) and the Dutch Society of Rheumatology Nurses (N = 227). Descriptive statistics, independent samples t -test and Pearson chi-square tests were used for statistical analysis. Results., A total of 494 nurses returned questionnaires (response rate 48%). In general, their knowledge about rheumatoid arthritis fatigue was in accordance with the literature and all indicated a positive attitude towards assessing and managing rheumatoid arthritis-related fatigue. However, respondents reported contradictory views about managing fatigue. Although they believed that other team members could help patients, they seldom referred patients on to other professionals. Although nurses believed that other advice besides pacing and balance between activity and rest might help, they did not offer this to patients. Despite acknowledging that there is poor communication about fatigue between patients and nurses, respondents reported that it is patients rather than nurses who raise the issue of fatigue in consultations. Conclusion., British and Dutch rheumatology nurses are sympathetic but do not know how to manage rheumatoid arthritis-related fatigue. Strategies to support self-management for this fatigue, and to increase communication between healthcare professionals and patients, should be initiated to help improve patient outcomes for rheumatoid arthritis-related fatigue. [source]

Fatigue Predicts Mortality in Older Adults

JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 10 2008
Susan E. Hardy MD
OBJECTIVES: To determine the association between fatigue and survival over 10 years in a population of older community-dwelling primary care patients. DESIGN: Prospective cohort study. SETTING: Medicare health maintenance organization and Veterans Affairs primary care programs. PARTICIPANTS: Older primary care patients (N=492). MEASUREMENTS: Fatigue, operationalized as feeling tired most of the time, was assessed at baseline. Mortality was ascertained from the National Death Index. Covariates included demographics, comorbidity, cognitive function, depressive symptoms, body mass index, self-rated health, functional status, and gait speed. RESULTS: Mortality rates at 10 years were 59% (123/210) for older adults with fatigue, versus 38% (106/282) for those without fatigue (P<.001). After adjustment for multiple potential confounders, participants who were tired at baseline had a greater risk of death than those who were not (hazard ratio=1.44, 95% confidence interval=1.08,1.93). CONCLUSION: A single simple question "Do you feel tired most of the time?" identifies older adults with a higher risk of mortality. Further research is needed to identify and characterize the underlying mechanisms of fatigue, to develop and test specific treatments, and to determine whether improvement leads to decreased morbidity and mortality. [source]

The fatigue experiences of older Taiwanese women with breast cancer

JOURNAL OF CLINICAL NURSING, Issue 5-6 2010
Sung-Ling Tsai
Aims and objectives., This study explored the fatigue experiences in older Taiwanese women with breast cancer. Background., Cancer is a common disease for older people, and breast cancer ranks second in occurrence among all cancers. Fatigue is the most frequently seen symptom, with more than 90% of cancer patients having such experiences. Fatigue may lead to functional dependence, affecting the care and quality of life for this older population. Design., A qualitative design was used in this study. Methods., In-depth interviews were conducted with participants being treated at the oncology outpatient department in a teaching hospital in northern Taiwan. Data were collected from November 2006,March 2007. Results., The study included 15 women, aged 65,82, with breast cancer. Analysis of the interviews revealed three themes: factors related to fatigue, interpretation of fatigue and ways to deal with fatigue. The factors related to fatigue arose from treatment, symptom distress and the impact of their emotions. Participants interpreted the fatigue as an inevitable normal reaction, and they were embarrassed to share its occurrence with others. Although fatigue made participants suffer, they found the ways to decrease the feeling of fatigue using psychological adjustments, practical changes and support systems. Conclusions., Facing the multilayered influences from treatments and ageing, older women with breast cancer considered fatigue as a physical and psychological expression. By raising the awareness of fatigue, nurses can help this older population manage or relieve fatigue by controlling symptoms, providing emotional support and making related resources available. Relevance to clinical practice., The results of this study can enhance the sensitivity and evaluation abilities of nurses in dealing with the cancer-related fatigue in older women with breast cancer. [source]