Évaluation de la force des muscles respiratoires : données récentes (1998-2004)

[Inspiratory muscle training during pulmonary rehabilitation]

INTRODUCTION

Inspiratory muscle training (IMT) is part of the management of patients with pulmonary diseases during rehabilitation. Since the last recommendations of the Société de pneumologie de langue française, several studies have focused on the role of inspiratory muscle training during pulmonary rehabilitation.

BACKGROUND

IMT, in comparison to standard care or sham-IMT, improves the strength and endurance of the inspiratory muscles, decreases dyspnoea during the activities of daily living, improves walking distance and quality of life. However, the different studies did not show an additional effect of IMT during a pulmonary rehabilitation program compared to a rehabilitation program without IMT, with regard to improvement of exercise capacity and quality of life.

OUTLOOK

One study showed an improvement in dyspnoea of effort, but these results are yet to be confirmed. Finally, it seems appropriate to associate IMT with an exercise-training program before chest or abdominal surgery, even if further studies are necessary.

CONCLUSION

During a pulmonary rehabilitation program, IMT does not provide additional benefits. However, when patients cannot perform a global exercise training, IMT has shown benefit. IMT provides additional benefits in pre-operative programs.

[Lung is also involved in juvenile dermatomyositis]

Juvenile dermatomyositis is the leading cause of chronic idiopathic inflammatory myopathy of auto-immune origin in children. Lung involvement in inflammatory myopathies is well described in adults, involving mostly interstitial lung disease, aspiration pneumonia and alveolar hypoventilation. We propose to describe its specificities in children. Pulmonary involvement may be asymptomatic and therefore must be systematically screened for. In case of clinical or functional respiratory abnormality, a chest computed tomographic (CT) scan is necessary. In children, a decrease of respiratory muscle strength seems common and should be systematically and specifically searched for by non-invasive and reproducible tests (sniff test). Interstitial lung disease usually associates restrictive functional defect, impairment of carbon monoxide diffusion and interstitial lung disease on CT scan. As in adults, the first-line treatment of juvenile dermatomyositis is based on corticosteroids. Corticosteroid resistant forms require corticosteroid bolus or adjuvant immunosuppressive drugs (methotrexate or cyclosporine). There is no consensus in pediatrics for the treatment of diffuse interstitial lung disease. Complications of treatment, including prolonged steroid therapy, are frequent and therefore a careful assessment of the treatments risk-benefit ratio is necessary, especially in growing children.

The lung is involved in juvenile dermatomyositis

BACKGROUND

Juvenile dermatomyositis (JDM) is the main cause of chronic idiopathic inflammatory myopathy of autoimmune origin in children. The aim of this multicenter prospective study was to describe respiratory status and treatment of children followed for JDM.

METHODS AND PATIENTS

Clinical manifestations, pulmonary function tests (PFT), chest high-resolution computed tomography (HRCT) scan results, and treatments and their adverse effects were analyzed in children followed for JDM.

RESULTS

Twenty-one patients (median age: 9.9 years; range: 20 months-18 years) were included. The median of disease duration at the time of the analysis was 3 years (range: 6 months-9 years 4 months). Overall 16 (76%) of 21 children presented with a respiratory involvement related to JDM including interstitial lung disease (n = 3) and/or respiratory muscle involvement (n = 7). Seven patients presented with other nonspecific manifestations. Three children had aspiration pneumonia. A chest HRCT was performed in 15 children, and abnormalities were observed in 12. PFT were performed in 20 of 21 patients. Seven showed functional abnormalities: restrictive ventilatory defect (n = 3) or obstructive ventilatory defect (n = 4). Six patients had abnormal respiratory muscle tests, including three with a restrictive ventilatory defect and one with an obstructive ventilatory defect. One other child with an acute aspiration pneumonia had a clearly muscle respiratory involvement but was too young to perform respiratory muscle tests and confirm this diagnosis. Treatment comprised systemic corticosteroid for all patients and adjuvant immunosuppressive therapy for 11. Adverse effects linked to treatment were reported in eight patients.

CONCLUSION

The frequency of lung involvement in children with JDM justifies systematic respiratory assessment with PFT including measures of respiratory muscle strength. We suggest that a chest HRCT scan is indicated in cases of respiratory symptoms and/or PFT abnormalities. Longitudinal studies are needed to assess pediatric characteristics, long-term outcomes, and responses to treatment taking into account the risk-benefit ratio.

[Inspiratory muscles strength training in recreational athletes]

INTRODUCTION

Respiratory muscles strength and endurance influence athletic performance. Besides conventional spirometry, sniff test, inspiratory and expiratory maximal pressures can directly assess respiratory muscle strength. Respiratory muscles can be train through a device offering inspiratory and expiratory resistance.

METHODS

Nineteen subjects aged 18 to 30 years and practicing leisure sport trained inspiratory muscles on Powerbreathe(®) for eight weeks. Resistance was set at 85% of maximal inspiratory pressure determined during a preliminary session. Evaluation was made trough voluntary and non-invasive methods on Macro 5000(®) (PI max, PE max and sniff test).

RESULTS

An increase of 21.77% of the maximum inspiratory pressure, 17% of the maximum expiratory pressure and 18% of the sniff test are recorded after eight weeks of training.

CONCLUSIONS

A specific training of inspiratory muscles (Powerbreathe(®) Sports performance) increases the power of these muscles (voluntary and non-invasive tests).