Inspiratory Muscle Strength in Acute Asthma

doi:10.1378/chest.120.3.757

Chest

Volume 120, Issue 3, September 2001, Pages 757-764

https://doi.org/10.1378/chest.120.3.757 Get rights and content

Abstract

Study objectives

The aim of this study was to measure inspiratory pressure-generating capacity in patients presenting with acute asthma, as it has been suggested that inspiratory muscle fatigue may contribute to breathlessness and acute respiratory failure.

Design

Descriptive study.

Setting

Emergency departments of two inner-city hospitals.

Patients

Fifty-one patients with acute asthma, and 45 patients without respiratory disease who served as control subjects.

Measurements and results

Maximum inspiratory pressure-generating capacity was measured soon after presentation by the sniff nasal inspiratory pressure (SNIP) method. The mean (SD) SNIP was 110 cm H₂O (23 cm H₂O) in men with asthma (mean for control subjects, 126 cm H₂O [25 cm H₂O]; p < 0.05) and 80 cm H₂O [24 cm H₂O] in women with asthma (mean for control subjects, 105 cm H₂O (26 cm H₂O); p < 0.01). In a second study of simultaneous SNIP and intrathoracic pressure measurements in a group of patients with acute asthma (n = 10) and control subjects (n = 11), the effect of airways obstruction on SNIP was assessed. The measurement of sniff esophageal pressure was more negative than SNIP by approximately 16% in asthmatic patients and by 4% in control subjects. Taking account of the likely effect of airways obstruction on SNIP, the reduction in inspiratory pressure-generating capacity that was observed in these patients with moderately severe acute asthma was minor and was consistent with the modest hyperinflation observed.

Conclusions

This study did not find evidence of inspiratory muscle weakness or fatigue in patients with moderately severe acute asthma presenting to the emergency department.

Section snippets

Materials and Methods

The study protocol was approved by the research ethics committees of the two hospitals concerned, and all patients gave informed consent

First Study

Measurements were made on 57 patients and 47 control subjects. The data on six patients with asthma and two control subjects were subsequently excluded from the analysis. The reasons for the exclusions from the asthma group were poor reversibility of airway obstruction (two patients), history of smoking (two patients), consolidation on chest radiograph (one patient), and uncertainty over the cause of breathlessness (one patient). In the control group, two patients had evidence of airways

Discussion

Our data show that the SNIP was around 20% lower in patients with acute moderately severe asthma than in a comparable group of control subjects. However, the difference in intrathoracic pressure generation between the asthmatic patients and the control subjects would have been considerably less than this when the loss of pressure transmission to the nostril in the asthmatic patients, as demonstrated in the second study, is taken into consideration. This showed that SNIP underestimated

Summary

The SNIP maneuver could be performed by all patients, and the reproducibility of this measurement was as good when the patients were ill as when they were well. A total of 15 measurements can be managed by acutely ill patients and provides a more accurate measurement of inspiratory muscle strength than does 10. Inspiratory muscle strength is close to normal in patients with moderately severe acute asthma who are presenting to emergency departments.

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Activity limitation and exertional dyspnea in adult asthmatic patients: What do we know?
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Citation Excerpt :
de Bruin et al. have observed significantly lower MIP values in asthmatic subjects than in healthy subjects (−52 ± 18 vs −73 ± 21 cm H2O respectively) [18] By studying steroid-dependent and non-dependent asthma patients, Perez et al. found, comparing to a control group, significant lower values in the first group but not in the second one [19]. Conversely, Stell et al., using another technique (Sniff Nasal Inspiratory Pressure, SNIP) showed that in patients with asthma of moderate severity values were comparable to those of non-asthmatic subjects [20]. Concerning the relationship between respiratory muscle strength and lung volume measurements, data are also contradictory.
Limitation of activity is the most cited symptom described by uncontrolled asthma patients. Assessment of activity limitation can be undertaken through several ways, more or less complex, subjective or objective. Yet little is known about the link between patients sensations and objective measurements.
The present review reports the current knowledge regarding activity limitation and symptom perception (i.e., exertional dyspnea) in adult patients with asthma. This work is based on references indexed by PubMed, irrespective of the year of publication.
Overall, patients with stable asthma do not have a more sedentary lifestyle than healthy subjects. However, during a cycle ergometric test, the maximal load is reduced when FEV1, FVC and muscle strengths are decreased. Additionally, during the six-minute walking test, mild asthma patients walk less than healthy subjects even if the minimal clinically important difference is not reached.
The major complaint of asthma patients when exercising is dyspnea that is mainly related to the inspiratory effort and also to dynamic hyperinflation in some circumstances. Finally, the administration of bronchodilator does not improve the ventilatory pattern and the exercise capacity of asthma patients and little is known on its effect on exertional dyspnea.
The present review allows to conclude that until now there is no gold standard test allowing the objective assessment of “activity limitation and exertional dyspnea” in asthma patients.
Role of maximal inspiratory presure in the evaluetion of respiratory muscle strength in asthmatics - Systematic review
2010, Revista Portuguesa de Pneumologia
A asma é uma doença crónica das vias aéreas que pode levar à diminuição da força muscular respiratória pela hiperinsuflação resultante ou o uso de corticosteróides em seu tratamento. Uma das formas de avaliar essa fraqueza muscular respiratória é a pressão inspiratória máxima (PImáx). Métodos: Foi realizada uma revisão sistemática através das bases de dados PUB-MED/MEDLINE, LILACS e SCIELO, utilizando as palavras-chaves: Asthma (asma), respiratory muscle (músculos respiratórios) e muscle strength (força muscular). Resultados: Foram encontrados cinquenta e seis artigos que avaliaram a PImáx em asmáticos; desses, trinta foram excluídos, ficando um total de vinte e seis artigos. Considerações finais: Através da presente revisão comprovamos a eficácia da utilização da Pimáx na avaliação da força muscular respiratória de asmáticos; no entanto, são necessários mais estudos a este respeito, para uma melhor compreensão do indivíduo asmático.
Rev Port Pneumol 2010; XVI (3): 463-470
Asthma is a chronic illness of the airways that can reduce respiratory muscle strength due to the resulting hyperinflation or treatment with corticosteroids. One of the ways to evaluate this respiratory muscular weakness is the Maximal Inspiratory Pressure (PImax). Methods: A systematic review of the databases PUBMED/MEDLINE, LILACS and SCIELO was carried through, using the key words: Asthma, respiratory muscle and muscle strength. Results: Fifty were found and six articles that evaluated the PImax in asthmatics, from these, thirty were excluded, making a total of twenty six articles. Final considerations: Through the present revision we show the effectiveness of PImax in evaluating respiratory muscle strength in asthmatics. More studies are needed, however, fot better understanding of the asthmatic individual.
Rev Port Pneumol 2010; XVI (3): 463-470
Changes in respiratory and peripheral muscle function in asthmatic children: Effects of inhaled corticoids
2010, Anales de Pediatria
El asma es la enfermedad crónica más común en los niños y los adolescentes. Las sobrecargas mecánicas intermitentes durante las crisis pueden inducir cambios funcionales en los músculos respiratorios, que experimentan fenómenos de adaptación. Este trabajo pretende evaluar el estado funcional muscular respiratorio y periférico en niños asmáticos que reciben corticoides inhalados y conocer la correlación entre la función muscular y la función respiratoria.
Se seleccionó a 12 niños con asma mayores de 7 años de edad y tratados durante al menos 2 años con corticoides inhalados a dosis intermedias (budesonida ≥400 μg o fluticasona ≥200 μg) y a 7 niños controles sanos emparejados por edad. Se determinaron espirometría forzada, volúmenes pulmonares estáticos, resistencia de las vías aéreas, presiones inspiratoria y espiratoria máximas, función muscular esquelética periférica y composición corporal mediante bioimpedanciometría.
Las variables antropométricas, nutricionales y de función muscular periférica fueron equivalentes en ambos grupos. Los niños asmáticos presentaban signos de atrapamiento aéreo e hiperinsuflación pulmonar y valores de presión inspiratoria máxima más elevados.
No se encuentra evidencia de que los esteroides inhalados a dosis altas y de forma crónica deterioren la función muscular respiratoria o periférica en los niños asmáticos. En cambio, se encuentran signos de adaptación muscular respiratoria frente a la sobrecarga a largo plazo que supone el asma persistente. El llamado “efecto entrenamiento” aparenta estar limitado únicamente a los músculos de la inspiración.
Asthma is the most common chronic disease in children and adolescents. The intermittent mechanical overloads during crises can lead to functional changes in the respiratory muscles, which experience adaptation phenomena. This article attempts to evaluate the respiratory and peripheral muscle state in asthmatic children who receive inhaled corticoids, and to find out if there is an association between muscle function and respiratory function.
The study involved 12 children over 7-years old with asthma and treated with inhaled corticoids for at least 2 years at intermediate doses (budesonide ≥400 ug, or fluticasone ≥200 ug) and 7 healthy control children paired by age. The following were determined: forced spirometry, static lung volumes, airway resistance, maximum inspiratory and expiratory pressures, peripheral musculo-skeletal function, and body composition using bioimpedance measurements.
The anthropometric, nutritional variables and peripheral muscle function were similar in both groups. The asthmatic children showed signs of air trapping, lung hyperinflation, and higher maximum inspiratory pressure values.
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Chest

Clinical InvestigationsMuscle StrengthInspiratory Muscle Strength in Acute Asthma

Abstract

Study objectives

Design

Setting

Patients

Measurements and results

Conclusions

Section snippets

Materials and Methods

First Study

Discussion

Summary

Chest

Sniff nasal inspiratory pressure: reference values in caucasian children

Am J Respir Crit Care Med

Repeatability and method comparison

Thorax

Further experimental designs

Dependence of maximal sniff generated mouth and transdiaphragmatic pressure on lung volume

Thorax

Mechanical load and inspiratory muscle action during induced asthma

Am Rev Respir Dis

Strength and endurance of inspiratory, expiratory, and limb muscles in asthma

Am Rev Respir Dis

Lung volume changes in asthma measured concurrently by two methods

Am Rev Respir Dis

Diaphragmatic fatigue in man

J Appl Physiol

Increased lung volume limits endurance of inspiratory muscles

J Appl Physiol

Clinical Investigations
Muscle Strength
Inspiratory Muscle Strength in Acute Asthma