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

Respiratory muscle fatigue is induced experimentally by adding high external resistances to breathing. The role played by respiratory muscle fatigue in exercise limitation and in acute respiratory failure is still unclear. The electromyogram often reflects contractions beyond the fatigue threshold, but overt force failure has been only rarely demonstrated under these circumstances. Hypercapnic ventilatory failure may possibly not result from fatigue, but rather from an adaptation of the respiratory system for avoiding fatigue. The treatment of fatigue comprises respiratory muscle support by adequate nutrition and oxygen delivery, and if needed respiratory muscle rest by mechanical ventilation.
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PMID:[Fatigue of the respiratory muscles]. 154 80

The authors report a 56-year-old woman with Ramsey Hunt syndrome with multiple cranial nerve paralysis and acute respiratory failure. Five days before admission, she experienced right otalgia and right facial pain and consulted an otolaryngologist of our hospital, who diagnosed the illness as acute parotitis and laryngopharyngitis. One day before admission, she experienced mild dyspnea and general fatigue and came to our hospital emergency room. A chest X-ray film revealed no abnormalities but some blisters were observed around her right ear. The next day, her dyspnea became more severe and she was admitted. A chest X-ray film on admission revealed right lower lobe consolidation, and neurological examination disclosed multiple cranial nerve paralysis, i.e., paralysis of the right fifth, seventh, eighth, ninth, tenth, eleventh, twelfth and left tenth cranial nerve. The serum titer of anti-herpes zoster antibody was elevated to 1,024, and the patient was diagnosed as having Ramsey Hunt syndrome with multiple cranial nerve paralysis. Arterial blood gas analysis revealed hypoxemia with hypercapnea, which was considered to be due to aspiration pneumonia and central airway obstruction caused by vocal cord paralysis. Mechanical ventilation was soon instituted and several antibiotics and acyclovir were administered intravenously, with marked effects. Three months after admission, the patient was discharged with no sequelae except mild hoarseness. Patients with herpes zoster oticus, facial nerve paralysis and auditory symptoms are diagnosed as having Ramsey Hunt syndrome. This case was complicated by lower cranial nerve paralysis and acute respiratory failure, which is very rare.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[A case of Ramsey Hunt syndrome with multiple cranial nerve paralysis and acute respiratory failure]. 175 19

Patients with chronic respiratory insufficiency due to severe chronic obstructive pulmonary disease (COPD) and presumed respiratory muscle fatigue may benefit from therapeutic maneuvers aimed at reducing the magnitude of inspiratory muscle effort. Recent work has demonstrated that continuous positive airway pressure (CPAP) can significantly reduce inspiratory effort and work of breathing in COPD patients with acute respiratory failure. Accordingly it was reasoned that prolonged CPAP administration may similarly reduce the work of breathing in stable COPD patients with chronic respiratory insufficiency, thereby allowing recovery from respiratory muscle fatigue. The purpose of this study was to determine the feasibility of employing nasal CPAP during sleep as a means of implementing this approach to reducing inspiratory muscle effort in such patients. Standard polysomnographic parameters were recorded during nocturnal administration of nasal CPAP in eight stable patients with severe COPD (FEV1 = 26.7 +/- 3.9% of predicted). Esophageal pressure, diaphragmatic (EMGdi) and parasternal intercostal (EMGic) electromyographic activity, arterial oxyhemoglobin saturation (SaO2), and transcutaneous PCO2 (PtcCO2) were also measured. Breathing pattern was determined by respiratory inductive plethysmography. In each patient an optimum level of nasal CPAP could be determined that produced consistent reductions in indices of inspiratory muscle effort without changing tidal volume or breathing frequency. Highly significant reductions in the tidal excursions of esophageal pressure and the pressure-time integral for the inspiratory muscles occurred at the optimum CPAP level in all patients. EMGdi and EMGic were similarly reduced. SaO2 and PtcCO2 were unaffected by CPAP. These results indicate that nasal CPAP can effectively reduce inspiratory muscle effort during sleep in patients with severe COPD.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Nasal continuous positive airway pressure facilitates respiratory muscle function during sleep in severe chronic obstructive pulmonary disease. 202 45

Inspiratory muscle fatigue has been documented during loaded breathing or acute respiratory failure, but its role in exercise limitation is still undetermined. Electromyographic (EMG) signs of diaphragmatic fatigue develop in normal subjects hyperventilating above 70% of maximal voluntary ventilation (MVV), a ventilatory level commonly attained at peak exercise. EMG signs of diaphragmatic fatigue also occur during high power cycling exercise in normal subjects and chronic obstructive pulmonary disease (COPD) patients. However, a loss of respiratory muscle strength has rarely been documented following strenuous physical exercise with techniques independent of the subjects' collaboration. Prior inspiratory muscle fatigue decreases exercise tolerance in normal subjects but its effect is largely unknown in COPD patients. Respiratory muscle rest by negative pressure ventilation was reported to improve exercise tolerance in COPD, but this beneficial effect was not confirmed by controlled studies. The effect of inspiratory muscle training on exercise tolerance is still undefined by existing data, in part because of differences in methods and selection criteria between studies. Although respiratory muscle fatigue may occur during exercise, it is not clearly established whether interventions directed at respiratory muscles may improve exercise tolerance in COPD.
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PMID:Respiratory muscle fatigue limiting physical exercise? 202 29

Fatigue of the respiratory muscles is now well documented but still remains a process that cannot be assessed easily. Several methods are available to detect fatigue; they represent windows allowing different viewpoints on the same phenomenon. The definition and determinants of respiratory muscle fatigue and some of the methods used to detect it are reviewed. On the basis of the available evidence provided by each of these methods, the role played by muscle fatigue in acute respiratory failure (ARF) is discussed.
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PMID:Muscle fatigue in acute respiratory failure. 211 99

In COLD, the inspiratory muscles are severely disadvantaged by virtue of the hyperinflation that accompanies this disorder. Such mechanical disadvantage will lead clinically, in the stable patient, to the active recruitment of the accessory muscles of inspiration and to a pattern of rapid, shallow breathing that may be due to either peripheral (muscle) or central (neurogenic) influences thought to be linked to a critical tension-time index of the inspiratory muscles. This pattern appears to be all the more pronounced in the patient with acute respiratory failure and is frequently accompanied by disordered rib cage-abdominal movements. While these movements may reflect the muscles' attempts to stave off fatigue, they may also imply that if the imposed mechanical stress is unrelieved, muscle failure will ensue. In the laboratory, mechanical disadvantage is marked by diminished inspiratory mouth pressures. Because of wide scatter, a low mouth pressure beyond that which can be explained by hyperinflation alone should be confirmed by an assessment of Pesosniff or by the measurement of transdiaphragmatic pressure. Muscle endurance, also compromised in this condition, can be assessed indirectly by the measurement of MVV or MSVC, or more directly by an invasive assessment of the tension-time index and endurance time of the diaphragm or noninvasively by the Endurance Index of McKenzie and Gandevia. And finally, once muscle failure is pending or has been established, a program of muscle rest, either complete or partial, pharmacotherapy, and goal-specific training should be instituted.
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PMID:Assessment of respiratory muscle dysfunction in chronic obstructive lung disease. 218 36

Mechanical ventilation is indicated in acute respiratory failure, especially in so-called pump failure as occurs in status asthmaticus, pneumonia and ARDS due to respiratory muscle fatigue. Using clinical parameters (inspiratory paradox, respiratory alternans), together with blood gas analysis and chest X-ray morphology, the indication can be established on a rational basis. The aims of therapy are tissue oxygenation and cure of the underlying disease which has led to respiratory failure. By adapting ventilator settings to the respiratory mechanics of the individual patient, complication due to barotrauma can be avoided. Respiratory muscle rest can be assessed by monitoring tracheal pressure time curves. Unconventional methods using very small t idal volumes and very high frequency so far have no clearcut indications, as they are still investigational.
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PMID:[Indications for artificial ventilation in status asthmaticus, adult respiratory distress syndrome and pneumonia]. 219 24

We report a 47-year-old man diagnosed as angio-immunoblastic lymphadenopathy with dysproteinemia (AILD) with fibrosis of the bone marrow, lymph node, liver and spleen, and proliferation of epithelioid cells in lymph node. He was admitted to a hospital in May, 1980 because of general fatigue, cough, fever and systemic lymphadenopathy. The diagnosis of AILD was based on a biopsy of right cervical lymph node. His symptoms were improved but recurred with the addition of icterus and progressive pancytopenia with decrement of prednisolone. He was referred to our hospital in July, 1980 and his physical examination revealed generalized lymphadenopathy, icterus and hepatosplenomegaly. Hemogram showed pancytopenia, and needle biopsy of the bone marrow disclosed fibrosis. Sections from the lymph node showed AILD with proliferation of epithelioid cells. Administration of 60 mg/day of prednisolone improved the fever, lymphadenopathy and hepatosplenomegaly. However he died suddenly of acute respiratory failure on July 30. Autopsy showed fibrosis of bone marrow, lymph node, liver and spleen with infiltration of abnormal lymphocytes, and pulmonary aspergillosis.
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PMID:[Angio-immunoblastic lymphadenopathy with fibrosis of bone marrow, lymph node, liver and spleen, and proliferation of epithelioid cells in lymph nodes]. 221 92

Nine subjects with severe chronic obstructive pulmonary disease (COPD) in acute respiratory failure (ARF) and with marked weakness of the respiratory muscles (Group A) underwent intermittent negative pressure ventilation by means of an iron lung (8 h daily for 7 days). Seven subjects with COPD in stabilized chronic respiratory failure (Group B) were studied as controls and submitted to the same medical therapy without ventilator treatment. Functional respiratory tests were performed before and after 7 days of treatment. After ventilatory treatment, Group A showed an increase of maximum inspiratory pressure (PImax), maximum expiratory pressure (PEmax), vital capacity (VC), arterial oxygen tension (PaO2), pH and a decrease of residual volume (RV), total lung capacity of (TLC) and arterial carbon dioxide tension (PaCO2) (all statistically significant). No improvement was ascertained in the functional parameters of Group B. The expiratory muscles seem to play a determining role in ARF. We conclude that the iron lung is a useful therapeutic defence in removing muscular fatigue and in restoring a good level of respiratory compensation of ARF in severe COPD.
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PMID:Respiratory muscle insufficiency in acute respiratory failure of subjects with severe COPD: treatment with intermittent negative pressure ventilation. 237 75

Persistent inability to tolerate discontinuation from mechanical ventilation is frequently encountered in patients recovering from acute respiratory failure. We studied the ability of inspiratory pressure support, a new mode of ventilatory assistance, to promote a nonfatiguing respiratory muscle activity in eight patients unsuccessful at weaning from mechanical ventilation. During spontaneous breathing, seven of the eight patients demonstrated electromyographic signs of incipient diaphragmatic fatigue. During ventilation with pressure support at increasing levels, the work of breathing gradually decreased (p less than 0.02) as well as the oxygen consumption of the respiratory muscles (p less than 0.01), and electrical signs suggestive of diaphragmatic fatigue were no longer present. In addition, intrinsic positive end-expiratory pressure was progressively reduced. For each patient an optimal level of pressure support was found (as much as 20 cm H2O), identified as the lowest level maintaining diaphragmatic activity without fatigue. Above this level, diaphragmatic activity was further reduced and untoward effects such as hyperinflation and apnea occurred. When electrical diaphragmatic fatigue occurred, the activity of the sternocleidomastoid muscle was markedly increased, whereas it was minimal when the optimal level was reached. We conclude that in patients demonstrating difficulties in weaning from the ventilator: (1) pressure support ventilation can assist spontaneous breathing and avoid diaphragmatic fatigue (pressure support allows adjustment of the work of each breath to provide an optimal muscle load); (2) clinical monitoring of sternocleidomastoid muscle activity allows the required level of pressure support to be determined to prevent fatigue.
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PMID:Inspiratory pressure support prevents diaphragmatic fatigue during weaning from mechanical ventilation. 267 10


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