The COPD assessment test and the modified Medical Research Council scale are not equivalent when related to the maximal exercise capacity in COPD patients.

INTRODUCTION: The management and treatment of Chronic Obstructive Pulmonary Disease (COPD) are based on a cutoff point either of ≥ 10 on the COPD Assessment Test (CAT) or of ≥ 2 of the Medical Research Council (mMRC). Up to now, no study has assessed the equivalence between CAT and mMRC, as related to exercise tolerance in COPD. The aim of this study was to investigate as primary outcome the relationship between CAT and mMRC and maximal exercise capacity in COPD patients. We also evaluated as secondary outcome the agreement between CAT (≥ 10) and mMRC (≥ 2) to categorize patients according to their exercise tolerance. MATERIAL AND METHODS: 118 consecutive COPD patients (39 females), aged between 47 and 85 years with a wide range of airflow obstruction and lung hyperinflation were studied. Maximal exercise capacity was assessed by cardiopulmonary exercise test. RESULTS: CAT and mMRC scores were significantly related to VO2 peak (p<0.01). CAT (≥ 10) and mMRC (≥ 2) have a high likelihood to be associated to a value of VO2 peak less than 15.7 and 15.6 mL/kg/min, respectively. The interrater agreement between CAT (≥ 10) and mMRC (≥ 2) was found to be fair (κ = 0.20) in all patients but slight when they were subdivided in those with VO2 peak < 15 mL/kg/min and in those with VO2 peak ≥ 15 mL/kg/min (κ = 0.10 and κ = 0.20 respectively). CONCLUSION: This study shows that CAT and mMRC are useful tools to predict exercise tolerance in COPD, but they cannot be considered as supplementary measures.

The value of cough peak flow in the assessment of cough efficacy in neuromuscular patients. A cross sectional study.

BACKGROUND: Cough efficacy assessment is of clinical relevance in neuromuscular patients. Tests of varying complexity and invasiveness, such as cough peak flow (CPF), maximal expiratory pressure (PEmax) and gastric pressure during cough (Cough Pgas) are routinely available. AIM: To assess the value of CPF, PEmax and Cough Pgas in the detection of ineffective cough in patients suffering from neuromuscular diseases. DESIGN: Prospective observational study. SETTING: Outpatient laboratory for respiratory muscle function assessment. POPULATION: Forty-nine patients with neuromuscular diseases (25 F, age 50 ± 15 years). METHODS: Each patient performed spirometry, CPF, PEmax, Cough Pgas and maximal inspiratory pressure (PImax). Normal values for each test were determined from published and in-house lab data. RESULTS: In all patients, vital capacity ranged from 46 to 119% of pred. Twenty seven percent of patients resulted under the lower normal limit of CPF and this percentage was significantly lower as compared to that of PEmax and Cough Pgas (51% and 53% respectively, P=0.013). Combining all three tests, the percentage of patients resulting below normal was 22% (P=0.638, as compared to CPF results alone). Additionally, CPF correlated significantly with PImax, PEmax, and Cough Pgas (P<0.01 for each correlation) and by multiple regression analysis PImax and PEmax contributed 65% of CPF variance. CONCLUSION: Our study shows that in neuromuscular patients, PEmax and Cough Pgas values may overdiagnose an ineffective cough. CPF, a non invasive and easy to perform test, is a global measure of voluntary cough. CLINICAL REHABILITATION SETTING:CPF may be relevant in the routine evaluation of patients with neuromuscular diseases, both in research and in rehabilitation settings.

High-resolution computed tomography evaluation of airway distensibility in asthmatic and healthy subjects.

PURPOSE: Airway-wall remodelling may result in reduced airway distensibility in bronchial asthma. This study evaluated the baseline airway calibre and distensibility in asthmatic patients by means of high-resolution computed tomography (HRCT). MATERIALS AND METHODS: We studied seven patients (two men, age range 36-69 years) with chronic asthma [forced expiratory volume in the first second (FEV(1)) range: 30%-87% of predicted; FEV1/forced vital capacity (FVC) range 48%-75% of predicted) under stable clinical conditions and six healthy control subjects (three men, age range 29-50 years). In all subjects, HRCT scanning, at suspended end-expiratory volume, was performed at rest and during ventilation with 6 and 12 cmH(2)O by nasal insufflation with continuous positive airway pressure (nCPAP), both at baseline and after inhalation of 200 mug oxitropium bromide metered dose inhaler (MDI). External and lumen diameter (mm) of the right apical upper lobe bronchus were measured in all HRCT scans. RESULTS: In asthmatics, 12 cmH(2)O insufflation significantly changed baseline lumen (3.3+/-0.7 mm vs. 3.8+/-0.6 mm; p<0.01) and external diameter (6.2+/-0.9 mm vs. 6.7+/-0.8 mm; p<0.05), whereas in healthy controls, both 6 and 12 cmH(2)O insufflation significantly changed baseline lumen diameter (4.0+/-1.6 mm vs. 4.8+/-1.6 mm and 4.7+/-1.7 mm; p<0.01). In asthmatic patients, oxitropium bromide inhalation significantly changed baseline lumen diameter (3.3+/-0.7 mm vs. 4.4+/-0.6 mm; p<0.05), whereas the application of 6 or 12 cmH(2)O insufflation did not modify any bronchial diameters. In healthy controls, oxitropium bromide inhalation significantly changed baseline lumen diameter (4.0+/-.6 mm vs. 5+/-1.5 mm; p<0.05). The application of 12 cmH(2)O but not of 6 cmH(2)O induced a significant change in lumen diameter (5.0+/-1.5 mm vs. 6,0+/-1.6 mm; p<0.05). CONCLUSIONS: Our results show that airway distensibility in asthmatic patients, as assessed by HRCT, can differ compared with that of healthy controls. HRCT can provide useful information on airway distensibility.

Assessment and monitoring of ventilatory function and cough efficacy in patients with amyotrophic lateral sclerosis.

Assessing and monitoring respiratory muscle function is crucial in patients with Amyotrophic Lateral Sclerosis, since impaired function can lead to either ventilatory failure or respiratory tract infection. Spirometry, diffusing capacity of the lung, breathing pattern, sleep study, blood gas analysis and respiratory muscle strength tests, as well as cough peak flow and cough expiratory volume measurements can provide relevant information on ventilatory function and cough efficacy. With regard to respiratory muscle strength testing, the rational approach consists in starting with volitional and non-invasive tests and later using invasive and non-volitional tests. This review focuses on both ventilatory and respiratory muscle strength testing, in order to undertake a timely treatment of respiratory failure and/or impaired cough efficacy. So far, the current literature has not highlighted any gold standard which stipulates when to commence ventilation and cough support in patients with Amyotrophic Lateral Sclerosis. A composite set of clinical and functional parameters is required for treatment scheduling to monitor lung involvement and follow-up in these patients.