Assessment of respiratory muscle function and strength. Postgrad Med J 74: 208-215

Faculty of Medicine, Kuwait University, Safat, Kuwait.
Postgraduate Medical Journal (Impact Factor: 1.45). 05/1998; 74(870):208-15. DOI: 10.1136/pgmj.74.870.208
Source: PubMed


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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    • "Respiratory muscle training (RMT) aims to improve respiratory performance by loading the respiratory system beyond its usual level of functioning, thereby creating a training effect [45-48]. Much research on RMT has been conducted in healthy subjects, in athletes, and in clinical populations with primary respiratory problems. "
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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 · 1.73 Impact Factor
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    • "Three maneuvers were performed separated by at least 30-second rest and continued until no further increase in pressure could be obtained [11]. Sniff test was considered as pathological if under 70 cmH 2 O for men and 60 cmH 2 O for women [11] [12] [13]. "
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    ABSTRACT: Objective. The aim of the present study was to evaluate sniff test, maximal inspiratory pressure, and presence of paradoxical inspiratory diaphragmatic movements and their diagnostic value in patients referred for suspicion of diaphragmatic dysfunction. Methods. Twenty-two patients (8 men and 14 women, years) with suspected diaphragmatic dysfunction were included. Pulmonary function test was evaluated by spirometry. Diaphragm dysfunction was diagnosed with unilateral phrenic nerve stimulation. Esophageal pressure was recorded during sniff test and maximal static inspiratory movements. Detection of paradoxical diaphragmatic movement was performed with anteroposterior projection of chest X-ray fluoroscopic video. Results. Phrenic nerve stimulation enabled diagnosis of diaphragmatic paralysis in 15 of the 22 patients. The remaining 7 patients had normal explorations. Lung volumes were significantly lower in patients with diaphragmatic paralysis than in control subjects, as maximal inspiratory pressure. No patient with normal diaphragmatic exploration had paradoxical inspiratory movement. The combined diagnostic value of reduced esophageal pressure during sniff test, reduced esophageal pressure during maximal static inspiratory movements, and presence of paradoxical inspiratory movement had a sensitivity of 87% and a specificity of 71%. Conclusion. Our results suggest that, in most cases, a combination of sniff test, maximal inspiratory pressure, and paradoxical inspiratory movement could help to diagnose diaphragmatic dysfunction. Nevertheless, phrenic nerve stimulation remains the best test for assessing diaphragmatic dysfunction.
    04/2014; 2014:1-6. DOI:10.1155/2014/683852
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    • "The other hand was used to cover the nose to avoid inspiration and expiration through the nose. The subjects were further instructed to watch their rib cages to avoid excessive rib movement (Syabbalo, 1998). The subjects were "
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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.
    African Journal for Physical Health Education, Recreation and Dance 01/2014; Supplement(2):45-61. · 4.03 Impact Factor
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