Assessment of respiratory muscle function and strength.

Faculty of Medicine, Kuwait University, Safat, Kuwait.
Postgraduate Medical Journal (Impact Factor: 1.55). 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: 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. DOI:10.2147/COPD.S58584
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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. DOI:10.1186/1745-6215-15-123 · 2.12 Impact Factor
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    ABSTRACT: Respiratory muscle weakness is a common feature of a multitude of cardiopulmonary diseases and has led to an increasing awareness that respiratory muscle weakness can be a compounding factor in many diseases associated with higher morbidity and mortality. The aim of the study was to ascertain the effect of breathing and aerobic training on manual volitional respiratory muscle strength and function in moderate, persistent asthmatics. Eighty-eight previously sedentary, moderate, persistent asthmatics were divided into either a non-exercising control (NON), endurance trained (ET), inspiratory and expiratory trained (IEB) or endurance trained combined with inspiratory and expiratory trained (COM) group. The exercise groups trained three times weekly over an eight-week period. The ET programme (n = 22) consisted of walking/jogging at 60% of individual age-predicted maximum heart rate, the IEB programme (n = 22) of inspiratory and expiratory training in a semi-recumbent position at varying inspiration, expiration ratios while the COM programme (n = 22) employed a combination of the ET and IEB programmes. The NON (n = 22) received no prescribed exercise and were instructed to continue their usual activities. ET, IEB and COM resulted in significant (p ≤ 0.05) strength improvements in eleven of the thirteen measured inspiratory muscles. ET and COM resulted in significant strength improvements in all seven of the measured expiratory muscles, while IEB improved the strength of five of the seven measured expiratory muscles, excluding left lattisimus dorsi and left quadratus lumborum. There were no significant changes in any of the measured variables in the NON group. Increases in respiratory muscle strength as a result of exercise training are essential to the patient to ensure ventilation by adapting to the increasing workloads associated with the disease. In addition, having multiple or alternative tests of respiratory muscle function available both increases diagnostic precision and makes assessment and follow-up possible in a range of clinical circumstances.
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