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John Moxham - One of the best experts on this subject based on the ideXlab platform.
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Respiratory Muscle strength as a predictive biomarker for survival in amyotrophic lateral sclerosis
American Journal of Respiratory and Critical Care Medicine, 2017Co-Authors: Michael I Polkey, John Moxham, R A Lyall, Ke Yang, Erin M Johnson, Nigel P LeighAbstract:Rationale: Biomarkers for survival in amyotrophic lateral sclerosis (ALS) would facilitate the development of novel drugs. Although Respiratory Muscle weakness is a known predictor of poor prognosis, a comprehensive comparison of different tests is lacking. Objectives: To compare the predictive power of invasive and noninvasive Respiratory Muscle strength assessments for survival or ventilator-free survival, up to 3 years. Methods: From a previously published report Respiratory Muscle strength measurements were available for 78 patients with ALS. Time to death and/or ventilation were ascertained. Receiver operating characteristic analysis was used to determine the cutoff point of each parameter. Measurements and Main Results: Each Respiratory Muscle strength assessment individually achieved statistical significance for prediction of survival or ventilator-free survival. In multivariate analysis sniff trans-diaphragmatic and esophageal pressure, twitch trans-diaphragmatic pressure (Tw Pdi), age, and maximal static expiratory mouth pressure were significant predictors of ventilation-free survival and Tw Pdi and maximal static expiratory mouth pressure for absolute survival. Although all measures had good specificity, there were differing sensitivities. All cutoff points for the VC were greater than 80% of normal, except for prediction of 3-month outcomes. Sequential data showed a linear decline for direct measures of Respiratory Muscle strength, whereas VC showed little to no decline until 12 months before death/ventilation. Conclusions: The most powerful biomarker for mortality stratification was Tw Pdi, but the predictive power of sniff nasal inspiratory pressure was also excellent. A VC within normal range suggested a good prognosis at 3 months but was of little other value.
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Respiratory Muscle strength and training in stroke and neurology a systematic review
International Journal of Stroke, 2013Co-Authors: Ross D Pollock, John Moxham, Gerrard F Rafferty, Lalit KalraAbstract:We undertook two systematic reviews to determine the levels of Respiratory Muscle weakness and effects of Respiratory Muscle training in stroke patients. Two systematic reviews were conducted in Ju...
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the value of multiple tests of Respiratory Muscle strength
Thorax, 2007Co-Authors: Joerg Steier, Gerrard F Rafferty, Michael I Polkey, Sundeep Kaul, John Seymour, Caroline J Jolley, William D C Man, Yuanming Luo, Michael Roughton, John MoxhamAbstract:Background: Respiratory Muscle weakness is an important clinical problem. Tests of varying complexity and invasiveness are available to assess Respiratory Muscle strength. The relative precision of different tests in the detection of weakness is less clear, as is the value of multiple tests. Methods: The Respiratory Muscle function tests of clinical referrals who had multiple tests assessed in our laboratories over a 6-year period were analysed. Thresholds for weakness for each test were determined from published and in-house laboratory data. The patients were divided into three groups: those who had all relevant measurements of global inspiratory Muscle strength (group A, n = 182), those with full assessment of diaphragm strength (group B, n = 264) and those for whom expiratory Muscle strength was fully evaluated (group C, n = 60). The diagnostic outcome of each inspiratory, diaphragm and expiratory Muscle test, both singly and in combination, was studied and the impact of using more than one test to detect weakness was calculated. Results: The clinical referrals were primarily for the evaluation of neuromuscular diseases and dyspnoea of unknown cause. A low maximal inspiratory mouth pressure (Pimax) was recorded in 40.1% of referrals in group A, while a low sniff nasal pressure (Sniff Pnasal) was recorded in 41.8% and a low sniff oesophageal pressure (Sniff Poes) in 37.9%. When assessing inspiratory strength with the combination of all three tests, 29.6% of patients had weakness. Using the two non-invasive tests (Pimax and Sniff Pnasal) in combination, a similar result was obtained (low in 32.4%). Combining Sniff Pdi (low in 68.2%) and Twitch Pdi (low in 67.4%) reduced the diagnoses of patients with diaphragm weakness to 55.3% in group B. 38.3% of the patients in group C had expiratory Muscle weakness as measured by maximum expiratory pressure (Pemax) compared with 36.7% when weakness was diagnosed by cough gastric pressure (Pgas), and 28.3% when assessed by Twitch T10. Combining all three expiratory Muscle tests reduced the number of patients diagnosed as having expiratory Muscle weakness to 16.7%. Conclusion: The use of single tests such as Pimax, Pemax and other available individual tests of inspiratory, diaphragm and expiratory Muscle strength tends to overdiagnose weakness. Combinations of tests increase diagnostic precision and, in the population studied, they reduced the diagnosis of inspiratory, specific diaphragm and expiratory Muscle weakness by 19–56%. Measuring both Pimax and Sniff Pnasal resulted in a relative reduction of 19.2% of patients falsely diagnosed with inspiratory Muscle weakness. The addition of Twitch Pdi to Sniff Pdi increased diagnostic precision by a smaller amount (18.9%). Having multiple tests of Respiratory Muscle function available both increases diagnostic precision and makes assessment possible in a range of clinical circumstances.
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Respiratory Muscle testing.
Monaldi archives for chest disease = Archivio Monaldi per le malattie del torace, 1996Co-Authors: John MoxhamAbstract:When addressing the question of whether or not the Respiratory Muscles are weak, and quantifying exactly how severe any weakness might be, it is sensible to regard the tests available as complimentary, and to proceed by using simple tests first and invasive tests only when appropriate. This sequential and complimentary approach is illustrated in table 1. Thus, if the supine vital capacity is normal, it is very unlikely that there is clinically significant Respiratory Muscle weakness. However, if the vital capacity is low, it may then be appropriate to measure the maximal inspiratory and maximal expiratory pressures. If the mouth pressures are normal, weakness has been excluded, but if the pressures are low it will then be necessary to proceed to the next tests on the list. Thus, the process continues and, when all of the tests have been performed, a comprehensive description can be achieved of any Respiratory Muscle weakness that is present. We now have the capacity, if we so wish, to measure Respiratory Muscle weakness accurately. The challenge is to use these techniques to demonstrate the undoubted importance of Respiratory Muscle weakness in a wide variety of clinical circumstances.
Craig A Harms - One of the best experts on this subject based on the ideXlab platform.
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Respiratory Muscle blood flow during exercise: effects of sex and ovarian cycle
Journal of Applied Physiology, 2017Co-Authors: Joshua R Smith, K. Sue Hageman, David C. Poole, Craig A Harms, Timothy I. MuschAbstract:It has been proposed that sex and ovarian cycle modulate Respiratory Muscle blood flow control during exercise. We demonstrate herein that neither sex nor ovarian cycle influences Respiratory muscl...
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effects of Respiratory Muscle unloading on exercise induced diaphragm fatigue
Journal of Applied Physiology, 2002Co-Authors: Mark A Babcock, Craig A Harms, David F Pegelow, Jerome A DempseyAbstract:We previously compared the effects of increased Respiratory Muscle work during whole body exercise and at rest on diaphragmatic fatigue and showed that the amount of diaphragmatic force output required to cause fatigue was reduced significantly during exercise (Babcock et al., J Appl Physiol 78: 1710, 1995). In this study, we use positive-pressure proportional assist ventilation (PAV) to unload the Respiratory Muscles during exercise to determine the effects of Respiratory Muscle work, per se, on exercise-induced diaphragmatic fatigue. After 8-13 min of exercise to exhaustion under control conditions at 80-85% maximal oxygen consumption, bilateral phrenic nerve stimulation using single-twitch stimuli (1 Hz) and paired stimuli (10-100 Hz) showed that diaphragmatic pressure was reduced by 20-30% for up to 60 min after exercise. Usage of PAV during heavy exercise reduced the work of breathing by 40-50% and oxygen consumption by 10-15% below control. PAV prevented exercise-induced diaphragmatic fatigue as determined by bilateral phrenic nerve stimulation at all frequencies and times postexercise. Our study has confirmed that high- and low-frequency diaphragmatic fatigue result from heavy-intensity whole body exercise to exhaustion; furthermore, the data show that the workload endured by the Respiratory Muscles is a critical determinant of this exercise-induced diaphragmatic fatigue.
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effects of Respiratory Muscle work on exercise performance
Journal of Applied Physiology, 2000Co-Authors: Craig A Harms, Thomas J Wetter, Claudette M St Croix, David F Pegelow, Jerome A DempseyAbstract:The normal Respiratory Muscle effort at maximal exercise requires a significant fraction of cardiac output and causes leg blood flow to fall. We questioned whether the high levels of Respiratory mu...
Hans-joachim Kabitz - One of the best experts on this subject based on the ideXlab platform.
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Recommendations for Respiratory Muscle testing
Pneumologie (Stuttgart Germany), 2014Co-Authors: Hans-joachim Kabitz, Stephan Walterspacher, U Mellies, C P Criée, W WindischAbstract:Based on the tremendous impact of impaired Respiratory Muscle function, tests on their function play a significant role in Respiratory and intensive care medicine. Besides differential diagnosing e.g. during prolonged weaning and quantification of impaired Respiratory Muscle function, e.g. in COPD, neuro-muscular diseases or ventilator-induced diaphragmatic dysfunction, those tests qualify for follow-up assessment, e.g. phrenic nerve lesions or specific Respiratory Muscle training. In general, (simple) volitional and (complex) non-volitional tests are available. Volitional tests aim at screening for potential Respiratory Muscle impairment, while non-volitional tests - including ultrasound application - are used to further specify low values assessed by volitional tests and to assess complex clinical conditions (e.g. intubated, sedated patients). Several tests are complementary or additive to each other. Complete assessment for Respiratory Muscle function, therefore, frequently requires the combination of different test regimes. The current recommendations include in-depth description and practical guidelines for the different tests and approaches to assess Respiratory Muscle function.
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Activation of Respiratory Muscles during Respiratory Muscle training
European Respiratory Journal, 2013Co-Authors: Stephan Walterspacher, David Walker, Fabian Pietsch, K Röcker, Hans-joachim KabitzAbstract:Introduction Respiratory Muscle training (RMT) is applied by athletes and in patients with Respiratory Muscle dysfunction. Yet it is unknown which Respiratory Muscle groups are mainly activated by RMT. Objective This study aimed at evaluating three RMT methods (Inspiratory Threshold Loading \[POWERbreathe\] (ITL), Targeted Resistive Breathing \[RespiFit S\] (TRB), Normocapnic Hyperpnoea \[SpiroTiger\] (NH)) with regard to their electromyographic (EMG) activation of three specific inspiratory Muscle groups (M. sternocleidomastoideus (EMGsterno), 2nd intercostal parasternal Muscles (EMGpara), Diaphragm (EMGdi)) in healthy subjects. Methods EMG recordings were analyzed as their RootMeanSquare (RMS) at the end of each randomized training session and normalized using the peak EMG recorded during maximum inspiratory maneuvers (Sniff nasal pressure: SnPna, maximal inspiratory mouth occlusion pressure: PImax) and expressed as EMG%max. Main Results 41 subjects were included. Recordings for EMGsterno and EMGpara were higher in ITL and NH than for TRB (p
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Respiratory Muscle function in interstitial lung disease
The European respiratory journal, 2012Co-Authors: Stephan Walterspacher, Daniel Schlager, David Walker, Joachim Müller-quernheim, Wolfram Windisch, Hans-joachim KabitzAbstract:Interstitial lung diseases limit daily activities, impair quality of life and result in (exertional) dyspnoea. This has mainly been attributed to a decline in lung function and impaired gas exchange. However, the contribution of Respiratory Muscle dysfunction to these limitations remains to be conclusively investigated. Interstitial lung disease patients and matched controls performed body plethysmography, a standardised 6-min walk test, volitional tests (Respiratory drive (P0.1), global maximal inspiratory mouth occlusion pressure (PImax), sniff nasal pressure (SnPna) and inspiratory Muscle load) and nonvolitional tests on Respiratory Muscle function and strength (twitch mouth and transdiaphragmatic pressure during bilateral magnetic phrenic nerve stimulation (TwPmo and TwPdi)). 25 patients and 24 controls were included in the study. PImax and SnPna remained unaltered (both p>0.05), whereas P0.1 and the load on the inspiratory Muscles were higher (both p
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Impairment of Respiratory Muscle function in pulmonary hypertension
Clinical Science, 2007Co-Authors: Hans-joachim Kabitz, Stephan Walterspacher, David Walker, Anja Schwoerer, Hinrich-cordt Bremer, Florian Sonntag, Vanessa Schaefer, Nicola Ehlken, Gerd Staehler, Michael HalankAbstract:It has been suggested that impaired Respiratory Muscle function occurs in patients with pulmonary hypertension (PH). However, comprehensive investigation of Respiratory Muscle function - including the application of non-volitional tests - needed to verify impairment of Respiratory Muscle strength in PH-patients has yet not been performed. Respiratory Muscle function was assessed in 31 PH-patients (20 female, mean pulmonary artery pressure 51±20 mmHg, median WHO-class 3.0±0.5, pulmonary arterial hypertension n=25, chronic-thrombembolic PH n=6) and in 31 control subjects (20 female) well-matched for gender, age and body-mass index. A six-minute walking test was performed to rate exercise capacity. Volitionally assessed maximal inspiratory (7.5±2.1 vs 6.2±2.8 kPa; p=0.04) and expiratory (13.3±4.2 vs 9.9±3.4 kPa; p
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Respiratory Muscle testing: state of the art
Pneumologie (Stuttgart Germany), 2007Co-Authors: Hans-joachim Kabitz, W WindischAbstract:Assessing Respiratory Muscle function has become more and more essential both in clinical research and in the broad field of Respiratory and intensive care medicine. In clinical practice, the assessment of Respiratory Muscle function is useful for differential diagnosis, for the quantification of Respiratory Muscle impairment and for follow-up assessments, for example, following Respiratory Muscle training or mechanical ventilation. Both volitional tests on Respiratory Muscle function, which are dependent on the patient making a truly maximal effort, and non-volitional tests exist. Non-invasive, less complex and most often volitional tests are suitable for screening. However, in case of pathological results these tests need to be complemented by the application of more complex, non-volitional and finally invasive techniques. This is particularly true if the cut-off value indicating no impairment is not achieved by the patient. In this case non-volitional tests are required in order to exclude pathological values resulting from sub-maximal efforts during volitional tests. In addition, isolated Respiratory Muscle impairments (e. g., solely diaphragmatic) might escape notice in certain tests on Respiratory Muscle function. For this reason, a diagnostic approach with the application of a combination of different tests should be chosen in those cases where Respiratory Muscle impairment is suspected. This current "state of the art" article gives a detailed description and comparative evaluation of the different volitional and non-volitional tests that are used for the assessment of Respiratory Muscle function.
Wolfram Windisch - One of the best experts on this subject based on the ideXlab platform.
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Respiratory Muscle involvement in sarcoidosis
Expert review of respiratory medicine, 2018Co-Authors: Tina Schreiber, Wolfram WindischAbstract:INTRODUCTION In sarcoidosis, Muscle involvement is common, but mostly asymptomatic. Currently, little is known about Respiratory Muscle and diaphragm involvement and function in patients with sarcoidosis. Reduced inspiratory Muscle strength and/or a reduced diaphragm function may contribute to exertional dyspnea, fatigue and reduced health-related quality of life. Previous studies using volitional and non-volitional tests demonstrated a reduced inspiratory Muscle strength in sarcoidosis compared to control subjects, and also showed that Respiratory Muscle function may even be significantly impaired in a subset of patients. Areas covered: This review examines the evidence on Respiratory Muscle involvement and its implications in sarcoidosis with emphasis on pathogenesis, diagnosis and treatment of Respiratory Muscle dysfunction. The presented evidence was identified by a literature search performed in PubMed and Medline for articles about Respiratory and skeletal Muscle function in sarcoidosis through to January 2018. Expert commentary: Respiratory Muscle involvement in sarcoidosis is an underdiagnosed condition, which may have an important impact on dyspnea and health-related quality of life. Further studies are needed to understand the etiology, pathogenesis and extent of Respiratory Muscle involvement in sarcoidosis.
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Respiratory Muscle function in interstitial lung disease
The European respiratory journal, 2012Co-Authors: Stephan Walterspacher, Daniel Schlager, David Walker, Joachim Müller-quernheim, Wolfram Windisch, Hans-joachim KabitzAbstract:Interstitial lung diseases limit daily activities, impair quality of life and result in (exertional) dyspnoea. This has mainly been attributed to a decline in lung function and impaired gas exchange. However, the contribution of Respiratory Muscle dysfunction to these limitations remains to be conclusively investigated. Interstitial lung disease patients and matched controls performed body plethysmography, a standardised 6-min walk test, volitional tests (Respiratory drive (P0.1), global maximal inspiratory mouth occlusion pressure (PImax), sniff nasal pressure (SnPna) and inspiratory Muscle load) and nonvolitional tests on Respiratory Muscle function and strength (twitch mouth and transdiaphragmatic pressure during bilateral magnetic phrenic nerve stimulation (TwPmo and TwPdi)). 25 patients and 24 controls were included in the study. PImax and SnPna remained unaltered (both p>0.05), whereas P0.1 and the load on the inspiratory Muscles were higher (both p
Marc Decramer - One of the best experts on this subject based on the ideXlab platform.
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Respiratory Muscle function and exercise limitation in patients with chronic obstructive pulmonary disease a review
Expert Review of Respiratory Medicine, 2018Co-Authors: Noppawan Charususin, Rik Gosselink, Marc Decramer, Sauwaluk Dacha, Andreas Von Leupoldt, Thomas Reijnders, Zafeiris Louvaris, Daniel LangerAbstract:Introduction: Respiratory Muscle dysfunction is common and contributes to dyspnea and exercise limitation in patients with chronic obstructive pulmonary disease (COPD). Improving dynamic function o...
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Respiratory Muscle assessment
2005Co-Authors: Thierry Troosters, Rik Gosselink, Marc DecramerAbstract:Respiratory Muscles generate the pressure differences driving ventilation. Respiratory Muscle weakness is hence an important clinical feature. In advanced stages, Respiratory Muscle weakness leads to Respiratory pump failure. Respiratory Muscle dysfunction (i.e. reduced strength or endurance) is to be distinguished from lung function abnormalities, and should be measured separately. Inspiratory Muscle weakness may partially explain dyspnoea and exercise intolerance. In addition, reduced Respiratory Muscle force has been shown to be an important predictive factor for poor survival in chronic obstructive pulmonary disease (COPD) [1], cystic fibrosis [2] and congestive heart failure [3]. In advanced stages the functional consequence of Respiratory Muscle weakness is a reduction of the operational lung volume and patients may require mechanical ventilation. Expiratory Muscle weakness leads to problems with speech, and mucus retention due to impaired cough efficacy. Measurement of Respiratory Muscle function is important in the diagnosis of Respiratory Muscle disease [4–6], or Respiratory Muscle dysfunction [7]. It may also be helpful in the assessment of the impact of chronic diseases [8–12] or their treatment [13–15] on the Respiratory Muscles. For example, specific inspiratory Muscle training has been reported to be useful in COPD only when patients present with significant Respiratory Muscle weakness [15], and tapering of oral corticosteroid treatment successfully restored Respiratory Muscle strength and dyspnoea in patients with corticosteroid-induced myopathy [16]. The present chapter aims to provide clinicians with some aspects of Respiratory Muscle testing. More detailed, excellent reviews on the pathophysiology and aetiology of Respiratory Muscle weakness are available elsewhere for the interested reader [17, 18]. Indications, techniques commonly used in clinical practice and issues important in the interpretation of the test results are the main focus of this chapter.
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Respiratory Muscle involvement in multiple sclerosis.
The European respiratory journal, 1999Co-Authors: Rik Gosselink, L Kovacs, Marc DecramerAbstract:Respiratory complications are common in the terminal stages of multiple sclerosis and contribute to mortality in these patients. When Respiratory motor pathways are involved, Respiratory Muscle weakness frequently occurs. Although it is well established that weakness of the Respiratory Muscles produces a restrictive ventilatory defect, the degree of Muscle weakness and pulmonary function are poorly related. Respiratory Muscle weakness was observed in patients with normal or near normal pulmonary function. Expiratory Muscle weakness is more prominent than inspiratory Muscle weakness and may impair performance of coughing. Subsequently, in addition to bulbar dysfunction, Respiratory Muscle weakness may contribute to ineffective coughing, pneumonia, and sometimes even acute ventilatory failure may ensue. Respiratory Muscle weakness may also occur early in the course of the disease. Recent studies suggest that the Respiratory Muscles can be trained for both strength and endurance in multiple sclerosis patients. Whether Respiratory Muscle training delays the development of Respiratory dysfunction and subsequently improves exercise capacity and cough efficacy, prevents pulmonary complications or prolongs survival in the long-term remains to be determined.