Assessment of respiratory muscle function and strength.

Faculty of Medicine, Kuwait University, Safat, Kuwait.
Postgraduate Medical Journal (Impact Factor: 1.61). 05/1998; 74(870):208-15. DOI: 10.1136/pgmj.74.870.208
Source: PubMed

ABSTRACT Measurement of respiratory muscle strength is useful in order to detect respiratory muscle weakness and to quantify its severity. In patients with severe respiratory muscle weakness, vital capacity is reduced but is a non-specific and relatively insensitive measure. Conventionally, inspiratory and expiratory muscle strength has been assessed by maximal inspiratory and expiratory mouth pressures sustained for 1 s (PImax and PEmax) during maximal static manoeuvre against a closed shutter. However, PImax and PEmax are volitional tests, and are poorly reproducible with an average coefficient of variation of 25%. The sniff manoeuvre is natural and probably easier to perform. Sniff pressure, and sniff transdiaphragmatic pressure are more reproducible and useful measure of diaphragmatic strength. Nevertheless, the sniff manoeuvre is also volition-dependent, and submaximal efforts are most likely to occur in patients who are ill or breathless. Non-volitional tests include measurements of twitch oesophageal, gastric and transdiaphragmatic pressure during bilateral electrical and magnetic phrenic nerve stimulation. Electrical phrenic nerve stimulation is technically difficult and is also uncomfortable and painful. Magnetic phrenic nerve stimulation is less painful and transdiaphragmatic pressure is reproducible in normal subjects. It is a relatively easy test that has the potential to become a widely adopted method for the assessment of diaphragm strength. The development of a technique to measure diaphragmatic sound (phonomyogram) during magnetic phrenic nerve stimulation opens the way for noninvasive assessment of diaphragmatic function.

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    ABSTRACT: Introduction: Respiratory muscle strength can be assessed by static mouth measurements of maximal inspiratory pressure (Pi max) and maximal expiratory pressure (Pe max). Impaired respiratory muscle strength is common in neuromuscular and obstructive pul-monary disease such as Cystic Fibrosis (CF). Maxi-mal respiratory pressures can easily be measured with a portable manometer on the bedside and in the community. Our objective was to compare maximal respiratory pressures as measured by standard labo-ratory equipment and the portable mouth pressure meter Micro RPM. Methods: Pi max and Pe max were assessed in 296 healthy subjects and patients with CF with the Micro RPM and standard laboratory equip-ment. The Micro RPM measures and digitally dis-plays maximal respiratory pressures after average-ing over a one second period. Standard laboratory equipment consisted of a differential pressure trans-ducer, whose amplified signals were analyzed by Lab-VIEW software. Each subject performed at least five reproducible maneuvers after familiarizing with the equipment. Results: The Micro RPM accurately measured maximal inspiratory and maximal expira-tory pressures both in healthy individuals as well as in patients with CF. Mean difference (standard de-viation) of the methods was 1.37 (17.73) cm H 2 O for Pi max maneuvers and 1.84 (9.09) cm H 2 O for Pe max maneuvers. Conclusions: The Micro RPM can relia-bly and accurately measure maximal respiratory mouth pressures and its use could be applied both in the clinical and the research setting.
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    ABSTRACT: After stroke, pneumonia is a relevant medical complication that can be precipitated by aspiration of saliva, liquids, or solid food. Swallowing difficulty and aspiration occur in a significant proportion of stroke survivors. Cough, an important mechanism protecting the lungs from inhaled materials, can be impaired in stroke survivors, and the likely cause for this impairment is central weakness of the respiratory musculature. Thus, respiratory muscle training in acute stroke may be useful in the recovery of respiratory muscle and cough function, and may thereby reduce the risk of pneumonia. The present study is a pilot study, aimed at investigating the validity and feasibility of this approach by exploring effect size, safety, and patient acceptability of the intervention.Methods/design: Adults with moderate to severe stroke impairment (National Institutes of Health Stroke Scale (NIHSS) score 5 to 25 at the time of admission) are recruited within 2 weeks of stroke onset. Participants must be able to perform voluntary respiratory maneuvers. Excluded are patients with increased intracranial pressure, uncontrolled hypertension, neuromuscular conditions other than stroke, medical history of asthma or chronic obstructive pulmonary disease, and recent cardiac events. Participants are randomized to receive inspiratory, expiratory, or sham respiratory training over a 4-week period, by using commercially available threshold resistance devices. Participants and caregivers, but not study investigators, are blind to treatment allocation. All participants receive medical care and stroke rehabilitation according to the usual standard of care. The following assessments are conducted at baseline, 4 weeks, and 12 weeks: Voluntary and reflex cough flow measurements, forced spirometry, respiratory muscle strength tests, incidence of pneumonia, assessments of safety parameters, and self-reported activity of daily living. The primary outcome is peak expiratory cough flow of voluntary cough, a parameter indicating the effectiveness of cough. Secondary outcomes are incidence of pneumonia, peak expiratory cough flow of reflex cough, and maximum inspiratory and expiratory mouth pressures. Various novel pharmacologic and nonpharmacologic approaches for preventing stroke-associated pneumonia are currently being researched. This study investigates a novel strategy based on an exercise intervention for cough rehabilitation.Trial registration: Current Controlled Trials ISRCTN40298220.
    Trials 04/2014; 15(1):123. · 2.21 Impact Factor
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    ABSTRACT: Maximal inspiratory pressure (MIP) is a marker for assessing the degree of respiratory muscle dysfunction. Muscle dysfunction represents a pathophysiological feature of chronic obstructive pulmonary disease. We aimed to determinate the MIP value in patients with airway obstruction, to evaluate the change in MIP with bronchodilator drug, and to show the relationship between the changes in MIP and disease characteristics. We evaluated 21 patients with airway obstruction at the Department of Pulmonary Medicine, Samsun Medicalpark Hospital, Samsun, Turkey. We performed pulmonary function tests, measurement of MIP values, and reversibility tests with salbutamol. The baseline spirometry results were: mean forced vital capacity (FVC), 3,017±1,020 mL and 75.8%±20.8%; mean forced expiratory volume in 1 second (FEV1), 1,892±701 mL and 59.2%±18.2%; FEV1/FVC, 62.9%±5.5%; peak expiratory flow, 53%±19%. The pre-bronchodilator MIP value was 62.1±36.9 cmH2O. The reversibility test was found to be positive in 61.9% of patients with salbutamol. The absolute change and percentage of change in FEV1 were 318±223 mL and 19.8%±16.7%, respectively. The MIP value was increased by 5.5 cmH2O (8.8%) and was 67.7±30.3 cmH2O after bronchodilation. There was no significant relationship between age, FEV1, reversibility, and change in MIP with bronchodilator. However, the increase in MIP with bronchodilator drug was higher in patients with low body mass index (<25 kg/m(2)). We noted a 13.1% increase in FVC, a 19.8% increase in FEV1, a 20.2% increase in peak expiratory flow, and an 8.8% increase in MIP with salbutamol. In conclusion; MIP increases with bronchodilator therapy, regardless of changes in lung function, in patients with airway obstruction. The reversibilty test can be used to evaluate change in MIP with salbutamol.
    International Journal of COPD 01/2014; 9:453-6.


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