Exercise-induced flow limitation, dynamic hyperinflation and exercise capacity in patients with bronchial asthma

Does the severity of asthma affect exercise capacity and daily physical activity?

OBJECTIVE

Exercise capacity, daily physical activity, and psychological profile are crucial aspects in the management of asthmatic patients. Whether these features are expressed in a different way in mild-moderate (MMA) and severe asthma (SA) is unknown.

METHODS

In this observational cross-sectional study, patients matching the American Thoracic Society/European Respiratory Society (ATS/ERS) definition for SA underwent incremental cardiopulmonary exercise testing (CPET), full lung function testing, and an evaluation of daily step count and physical activity. Questionnaires on quality of life, general fatigue, and presence of anxiety and depression traits (Hospital Anxiety and Depression Scale - HADS) were administered. Patients were compared with a cohort of age- and gender-matched MMA patients.

RESULTS

We enrolled 16 SA, 17 MMA patients, and 16 healthy subjects. Compared to MMA, SA subjects showed a median (interquartile range) reduced peak oxygen consumption during CPET (20.4 (17.2-23.3) vs. 25.6 (18.5-30.3) ml/min/kg; p = 0.019), a reduced resting lung function (FEV1% of predicted 77 (67-84) vs. 96 (84-100); p < 0.001) and a pronounced anxiety trait at HADS (9.5 (3-11.7) vs. 4.0 (2.0-7.5); p = 0.023). In addition, SA patients showed a significantly higher reduction in inspiratory capacity from rest to peak (310 (160-520) vs. 110 (-65-325) ml; p = 0.031). We found no significant differences in mean daily step count or quality of life.

CONCLUSIONS

Compared to MMA, SA patients present a reduced exercise capacity and a more pronounced anxiety trait, but not worse daily physical activity or quality of life. These aspects should be considered in the clinical management and research development of SA.

Investigation of dynamic hyperinflation and its relationship with exercise capacity in children with bronchiectasis

BACKGROUND AND AIM

Dynamic hyperinflation (DH) is a major contributor to exercise intolerance in patients with obstructive lung diseases. However, it has not been investigated in children with bronchiectasis (BE). We aimed to investigate dynamic ventilatory responses and their influence on functional exercise capacity in children with BE.

METHODS

Forty children with BE (mean forced expiratory volume in 1 s [FEV₁ ] = 78 ± 19%pred) were included. Six-minute walk test (6MWT) was conducted using Spiropalm 6MWT® for evaluating dynamic ventilatory responses including inspiratory capacity (IC), minute ventilation (VE), breathing reserve (BR) and respiratory rate (RR). A decrease of ≥100 ml in IC during exertion was defined as DH. Also, spirometry was performed, and peripheral muscle strength were measured.

RESULTS

Twenty patients (50%) developed DH, and four patients (10%) were ventilatory limited (BR < %30) during 6MWT. There was a 176 [100-590] ml decrease in IC after exertion in patients with DH. DH did not correlate to clinical or functional indicators of the disease, except for an increase in RR (∆RR) during exertion. High ∆RR was associated with presence of DH (r_pb = 0.390; p < 0.05). Clinical features, peripheral muscle strength, and Spiropalm 6MWT metrics including 6MWT distance did not differ between patients with and without DH. Univariate analysis revealed FVC% (R = 0.340), VE_peak (R = 0.565), quadriceps strength (R = 0.698) and handgrip strength (R = 0.711) were the only predictors of 6MWT distance (p < 0.05).

CONCLUSION

Although DH is common in children with BE, the severity of DH is rather low and may not seem to affect functional exercise capacity. However, peripheral muscle strength was a major contributor to functional exercise capacity.

Exercise-induced Bronchodilation Equalizes Exercise Ventilatory Mechanics despite Variable Baseline Airway Function in Asthma

PURPOSE

We quantified the magnitude of exercise-induced bronchodilation in adult asthmatics under conditions of narrowed and dilated airways. We then assessed the effect of the bronchodilation on ventilatory capacity and the extent of ventilatory limitation during exercise.

METHODS

Eleven asthmatics completed three exercise bouts on a cycle ergometer. Exercise was preceded by no treatment (trialCON), inhaled β2 agonist (trialBD), or a eucapnic voluntary hyperpnea challenge (trialBC). Maximal expiratory flow-volume maneuvers (MEFV) were performed before and within 40 s of exercise cessation. Exercise tidal flow-volume loops were placed within the preexercise and postexercise MEFV curve and used to determine expiratory flow limitation and maximum ventilatory capacity (V˙ECap).

RESULTS

Preexercise airway function was different among the trials (forced expiratory volume 1 s during trialCON, trialBD, and trialBC = 3.3 ± 0.8 L, 3.8 ± 0.8 L, and 2.9 ± 0.8 L, respectively; P < 0.05). Maximal expired airflow increased with exercise during all three trials, but the increase was greatest during trialBC (delta forced expiratory volume 1 s during trialCON, trialBD, and trialBC = +12.2% ± 13.1%, +5.2% ± 5.7%, +28.1% ± 15.7%). Thus, the extent of expiratory flow limitation decreased, and V˙ECap increased, when the postexercise MEFV curve was used. During trialCON and trialBC, actual exercise ventilation exceeded V˙ECap calculated with the preexercise MEFV curve in seven and nine subjects, respectively.

CONCLUSIONS

These findings demonstrate the critical importance of exercise bronchodilation in the asthmatic with narrowed airways. Of clinical relevance, the results also highlight the importance of assessing airway function during or immediately after exercise in asthmatic persons; otherwise, mechanical limitations to exercise ventilation will be overestimated.

Time to Move Beyond a "One-Size Fits All" Approach to Inspiratory Muscle Training

Inspiratory muscle training (IMT) has been studied as a rehabilitation tool and ergogenic aid in clinical, athletic, and healthy populations. This technique aims to improve respiratory muscle strength and endurance, which has been seen to enhance respiratory pressure generation, respiratory muscle weakness, exercise capacity, and quality of life. However, the effects of IMT have been discrepant between populations, with some studies showing improvements with IMT and others not. This may be due to the use of standardized IMT protocols which are uniformly applied to all study participants without considering individual characteristics and training needs. As such, we suggest that research on IMT veer away from a standardized, one-size-fits-all intervention, and instead utilize specific IMT training protocols. In particular, a more personalized approach to an individual's training prescription based upon goals, needs, and desired outcomes of the patient or athlete. In order for the coach or practitioner to adjust and personalize a given IMT prescription for an individual, factors, such as frequency, duration, and modality will be influenced, thus inevitably affecting overall training load and adaptations for a projected outcome. Therefore, by integrating specific methods based on optimization, periodization, and personalization, further studies may overcome previous discrepancies within IMT research.

Predictors of exercise-induced bronchoconstriction in subjects with mild asthma

Background

Physical effort is capable of triggering airway obstruction in asthmatics, the so-called exercise-induced bronchoconstriction in asthma (EIBa). This study was performed in subjects with mild persistent asthma, aiming to find predictors for developing EIBa.

Methods

In 20 subjects with mild asthma, measurements of baseline functional respiratory parameters and airways responsiveness by a methacholine challenge were obtained on the first day. A maximal, symptom-limited incremental cardiopulmonary exercise test (CPExT) was performed the day after, with subsequent, repeated maneuvers of maximal full forced expiration to monitor the FEV₁ change at 1,3,5,7,10 and 15 min after the end of the exercise.

Results

19 subjects completed the two-days protocol. No functional parameters both at rest and during effort were useful to predict EIBa after stopping exercise. In asthmatics with EIBa, mean Inspiratory Capacity (IC) did not increase with increasing ventilatory requirements during CPExT because 6 of them (50%) displayed dynamic pulmonary hyperinflation (DH), as documented by their progressive increase of end-expiratory lung volume. This subgroup, showing earlier post-exercise FEV₁ fall, had significantly lower forced mean expiratory flow between 25% and 75% of forced vital capacity (FEF_25-75%) at rest (p < 0.05) and higher airways responsiveness, expressed as PD₂₀FEV₁ (p < 0.05) as compared with other asthmatics with EIBa.

Conclusions

No functional respiratory parameters seem to predict EIBa in mild asthmatics. However, in those with EIBa, a subgroup developed DH during exercise, and this was associated with a baseline reduced forced expiratory flow rates at lower lung volumes and higher airway hyperresponsiveness, suggesting a prominent small airways impairment.

Serum periostin reflects dynamic hyperinflation in patients with asthma

Introduction

Dynamic hyperinflation (DH) is sometimes observed and is associated with impaired daily life activities of asthma. We assessed the relationship between DH and asthma biomarkers (blood eosinophil, fractional exhaled nitric oxide (F _eNO) and serum periostin) in patients with asthma.

Methods

Fifty patients with stable asthma were prospectively recruited and underwent blood test, F _eNO measurement, spirometry and metronome-paced tachypnoea (MPT) test to assess DH. In MPT tests, inspiratory capacity (IC) was measured at baseline and after 30 s of MPT with breathing frequencies of 20, 30 and 40 breaths·min^-1. DH was assessed by the decline of IC from baseline, and maximal IC reduction ≥10% was considered as positive DH.

Results

Thirty patients (60%) showed positive DH. Patients with positive DH showed higher serum periostin levels (107.0±30.7 ng·mL^-1) than patients with negative DH (89.7±23.7) (p=0.04). Patients in Global Initiative for Asthma treatment steps 4-5 (n=19) showed higher serum periostin levels (p=0.01) and more severe IC reduction after MPT (p<0.0001) than patients in steps 1-3 (n=31). Maximal IC reduction after MPT was significantly correlated with asthma control test score (r=-0.28, p=0.05), forced expiratory volume in 1 s (r=-0.56, p<0.0001), and serum periostin levels (r=0.41, p=0.003).

Conclusion

Serum periostin may have the possibility to reflect DH in patients with stable asthma.

Cardiopulmonary exercise testing in patients with asthma: What is its clinical value?

Asthma is one of the most common respiratory disorders, characterized by fully or largely reversible airflow limitation. Asthma symptoms can be triggered or magnified during exertion, while physical activity limitation is often present among asthmatic patients. Cardiopulmonary exercise testing (CPET) is a dynamic, non-invasive technique which provides a thorough assessment of exercise physiology, involving the integrative assessment of cardiopulmonary, neuromuscular and metabolic responses during exercise. This review summarizes current evidence regarding the utility of CPET in the diagnostic work-up, functional evaluation and therapeutic intervention among patients with asthma, highlighting its potential role for thorough patient assessment and physician clinical desicion-making.

The relationship between heart rate and VO2 in moderate-to-severe asthmatics

Objective: The main purpose of this study was to evaluate whether the %HRR-%VO₂R relationship and %HRR-VO_2peak relationship are affected in patients with moderate or severe asthma and whether airway obstruction and aerobic capacity influence these relationships.Methods: A linear regression was calculated using the paired %VO₂R-%HRR and %VO_2peak-%HRR for 93 subjects with asthma. The mean slope and y-intercept were calculated and compared with the line of identity (y-intercept = 0, slope = 1) for all patients and subgroups for the following conditions: low and normal VO_2peak and low and normal FEV₁.Results: The slope and intercepts of %VO₂R-%HRR were similar to the line of identity for all groups (p > 0.05), and the regressions between %HRR and %VO_2peak did not coincide with the line of identity for all groups (p < 0.05). There were no associations between the intercepts of the %HRR-VO_2peak and the %HRR-%VO₂R relationship with the VO_2peak (p > 0.05) or FEV₁ (p > 0.05).Conclusions: This is the first study to confirm a constant equivalence between %HRR and %VO₂R in outpatients with moderate or severe asthma. Our data also suggest that the relationship between %HRR and %VO_2peak is unreliable. These results support the use of %HRR in relation to %VO₂R to estimate exercise intensity in this population, independently of the pulmonary function and fitness level.

Dynamic hyperinflation impairs daily life activity in asthma

INTRODUCTION

Dynamic hyperinflation has been documented in asthma, yet its impact on overall health and daily life activities is unclear. We assessed the prevalence of dynamic hyperinflation in moderate to severe asthma and its relationship with the scores of a set of specific and general respiratory health questionnaires.

METHODS

77 nonsmoking asthma patients (Global Initiative for Asthma steps 4-5) were recruited consecutively and completed five questionnaires: Asthma Control Questionnaire, Clinical COPD (chronic obstructive pulmonary disease) Questionnaire, St George's Respiratory Questionnaire, London Chest Activity of Daily Living scale (LCADL) and Shortness of Breath with Daily Activities (SOBDA). Dynamic hyperinflation was defined as ≥10% reduction in inspiratory capacity induced by standardised metronome-paced tachypnoea. Associations between level of dynamic hyperinflation and questionnaire scores were assessed and adjusted for asthma severity.

RESULTS

81% (95% CI 71.7-89.4%) of patients showed dynamic hyperinflation. Higher levels of dynamic hyperinflation were related to poorer scores on all questionnaires (r=0.228-0.385, p<0.05). After adjustment for asthma severity, dynamic hyperinflation remained associated with poorer scores on LCADL (p=0.027) and SOBDA (p=0.031).

CONCLUSION

Dynamic hyperinflation is associated with poorer overall health and impaired daily life activities, independent of asthma severity. Because of its major impact on everyday life activities, dynamic hyperinflation is an important target for treatment in asthma.

[Dyspnoea in asthma: diagnostic approach]

Dyspnoea is a cardinal symptom of asthma and an essential part of assessing control of the disease. Its intensity is variable for the same level of bronchial obstruction, which suggests the involvement of other mechanisms. Therefore, it is extremely important to characterize and measure dyspnoea in asthmatic patients because its profile can be quantitatively and qualitatively modified by disease control, comorbidities and anxiety. Hence the value of using additional tools to ACT and ACQ because the latter do not characterize nor measure specifically dyspnoea in asthma. Different tools can be used in this regard, at rest as the subjective assessment of dyspnoea by scales such as the modified Medical Research Council (mMRC), the New York Heart Association (NYHA) and the Visual Analogue Scale (VAS) or more recently using the Dyspnea-12 and the Multidimensional Dyspnea Profile (MDP) questionnaire, which assesses the sensory and affective dimensions of dyspnoea; and during exercise testing such as the "modified" Borg scale, graduated from 0 to 10, or the VAS. Among the factors contributing to dyspnoea in asthmatic patients, probably bronchial obstruction, increased airway resistance and dynamic hyperinflation play an important role. Despite this, the asthmatic patient's description of dyspnoea may be masked by hyperventilation syndrome or other comorbidities that can easily be detected and treated through educational programs and targeted therapies.

Nonpharmacologic Strategies to Manage Exercise-Induced Bronchoconstriction

Pharmacologic management of exercise-induced bronchoconstriction (EIB) is the mainstay of preventative therapy. There are some nonpharmacologic interventions, however, that may assist the management of EIB. This review discusses these nonpharmacologic interventions and how they may be applied to patients and athletes with EIB.

Asthma - A Disease of How We Breathe: Role of Breathing Exercises and Pranayam

To describe the role of breathing exercises or yoga and/or pranayama in the management of childhood asthma. We conducted an updated literature search and retrieved relevant literature on the role of breathing exercises or yoga and/or pranayama in the management of childhood asthma. We found that the breathing exercises or yoga and/or pranayama are generally multi-component packaged interventions, and are described as follows: Papworth technique, Buteyko technique, Yoga and/or Pranayam. These techniques primarily modify the pattern of breathing to reduce hyperventilation resulting in normalisation of CO2 level, reduction of bronchospasm and resulting breathlessness. In addition they also change the behaviour, decrease anxiety, improve immunological parameters, and improve endurance of the respiratory muscles that may ultimately help asthmatic children. We found 10 clinical trials conducted in children with asthma of varying severity, and found to benefit children with chronic (mild and moderate) and uncontrolled asthma, but not acute severe asthma. Breathing exercises or yoga and/or pranayama may benefit children with chronic (mild and moderate) and uncontrolled asthma, but not acute severe asthma. Before these techniques can be incorporated into the standard care of asthmatic children, important outcomes like quality of life, medication use, and patient reported outcomes need to be evaluated in future clinical trials.

Thoracoabdominal Asynchrony Contributes to Exercise Limitation in Mild Asthmatic Subjects

This study aimed to better understand how subjects with stable asthma and without exercise-induced bronchoconstriction respond to mild exercise. Breathing pattern, chest wall compartmental and operational volumes, and thoracoabdominal asynchrony were assessed in 11 stable asthmatic subjects and 10 healthy subjects at rest and during exercise in a cycle-ergometer through optoelectronic plethysmography. Dyspnea and sensation of leg effort were assessed through Borg scale. During exercise, with similar minute ventilation, a significant lower chest wall tidal volume (p = 0.003) as well as a higher respiratory rate (p < 0.05) and rapid shallow breathing (p < 0.05) were observed in asthmatic when compared to healthy subjects. Asthmatic subjects exhibited a significantly lower inspiratory (p < 0.05) and expiratory times (p < 0.05). Intergroup analysis found a significant higher end-expiratory chest wall volume in asthmatic subjects, mainly due to a significant increase in volume of the pulmonary ribcage (RCp; 170 ml, p = 0.002), indicating dynamic hyperinflation (DH). Dyspnea and sensation of leg effort were both significantly greater (p < 0.0001) in asthmatic when compared to healthy subjects. In addition to a higher thoracoabdominal asynchrony found between RCp and abdominal (AB) (p < 0.005) compartments in asthmatic subjects, post-inspiratory action of the inspiratory ribcage and diaphragm muscles were observed through the higher expiratory paradox time of both RCp (p < 0.0001) and AB (p = 0.0002), respectively. Our data suggest that a different breathing pattern is adopted by asthmatic subjects without exercise-induced bronchoconstriction during mild exercise and that this feature, associated with DH and thoracoabdominal asynchrony, contributes significantly to exercise limitation.

Dynamic hyperinflation during the 6-min walk test in severely asthmatic subjects

We tested the hypothesis that dynamic hyperinflation develops in severe asthmatic subjects during exercise. Changes in inspiratory capacity (IC) were measured during the 6-min walk test (6MWT) in severe asthmatic subjects compared with chronic obstructive pulmonary disease (COPD) subjects with a similar degree of bronchial obstruction. We assessed whether changes in IC were associated with changes in dyspnoea perception.

27 severe asthmatic subjects (10 males and 17 females) and 43 COPD subjects (35 males and eight females) were recruited. The two groups performed similarly in the 6MWT (p=0.90). At the end of the test, the Borg score increased significantly in both groups (mean difference: for asthmatic subjects 1.7±1.6; p<0.0001; for COPD subjects 3.1±1.9; p<0.0001). IC measured at the beginning of 6MWT was not different between groups (2.25±0.47 L in asthmatic subjects versus 2.38±0.60 L in COPD subjects; p=0.32) and decreased in both groups (mean difference: for asthmatic subjects 0.160 L; p=0.02; for COPD subjects 0.164 L; p<0.0001). However, changes in IC were significantly associated with changes in the Borg score in the COPD group (r²=0.17; p=0.006), but not in the asthma group (r²=0.06; p=0.20).

In severe asthmatic subjects, IC significantly drops during the 6MWT to the same extent as COPD subjects with a similar degree of lung impairment, indicating the development of dynamic hyperinflation. Contrary to COPD, in asthmatic subjects the occurrence of dynamic hyperinflation was not associated with changes in dyspnoea perception.

Severe asthma is characterised by occurrence of dynamic hyperinflation during exercise; inspiratory capacity drops in severe asthmatic subjects during the 6MWT to the same extent as in COPD subjects with similar lung impairmenthttp://ow.ly/InfQ30jjivW

Accuracy of optoelectronic plethysmography in childhood exercise-induced asthma

OBJECTIVE

To assess the variations of end-expiratory volume of chest wall (EEVcw) measured by optoelectronic plethysmography (OEP) as a diagnostic tool in exercise-induced asthma (EIA) among asthmatic preschool children.

METHODS

Forty children diagnosed with asthma were included in the study. Spirometry was used as a gold standard test for comparison with OEP. A 10% decline in forced expiratory volume in 1 second was considered positive for EIA. OEP was performed with 8 cameras at a frequency of 60 Hz and 89 markers were placed on the thoraco-abdominal surface of participants. Following bronchoprovocation testing on a treadmill, series of OEP and spirometry were conducted between 5 and 30 minutes after exercise. To obtain the ideal cut-off point, a receiver operating characteristic (ROC) curve was constructed for the largest EEVcw. The highest Youden index was used as criteria to obtain the cut-off point with the best sensitivity and specificity.

RESULTS

Of the 40 children studied, 16 had EIA. According to the ROC curve, the cut-off point of 0.185% for EEWcw provided mean sensitivity (95% confidence interval) of 93.75% (0.69-0.99), for a specificity of 83.33% (0.63-0.95), when using the largest increase in the period of 5-30 minutes post-exercise. The low area of the ROC was 0.93 (0.85-1.00) for p < 0.001.

CONCLUSION

OEP can be accurately used to replace spirometry in asthmatic children unable to adequately execute the required manoeuvres.

Dynamic hyperinflation and exercise limitations in obese asthmatic women

Obese individuals and patients with asthma can develop dynamic hyperinflation (DH) during exercise; however, no previous study has investigated DH as a factor associated with reduced exercise capacity in obese asthmatic women. The aim of the present study was to examine the occurrence of DH and exercise limitations in obese asthmatics. Obese grade II [obese group (Ob-G); BMI 35-39.9 kg/m²; n=36] and nonobese [nonobese group (NOb-G); BMI 18.5-29.9 kg/m²; n=18] asthmatic patients performed a cardiopulmonary test to quantify peak V̇o₂ and a submaximal exercise test to assess DH. Anthropometric measurements, quadriceps endurance, and lung function were also evaluated. A forward stepwise regression was used to evaluate the association between exercise tolerance (wattage) and limiting exercise factors. Fifty-four patients completed the protocol. The Ob-G (n = 36) presented higher peak V̇o₂ values but lower power-to-weight ratio values than the NOb-G (P <0 .05). DH was more common in the Ob-G (72.2%) than in the NOb-G (38.9%, P < 0.05). The Ob-G had a greater reduction in the inspiratory capacity (-18 vs. -4.6%, P < 0.05). Exercise tolerance was associated with quadriceps endurance (r = 0.65; p<0.001), oxygen pulse (r = 0.52; p=0.001), and DH (r = -0.46, P = 0.005). The multiple regression analysis showed that the exercise tolerance could be predicted from a linear association only for muscular endurance (r = 0.82 and r² = 0.67). This study shows that dynamic hyperinflation is a common condition in obese asthmatics; they have reduced fitness for activities of daily living compared to nonobese asthmatics. However, peripheral limitation was the main factor associated with reduced capacity of exercise in these patients.NEW & NOTEWORTHY This is the first study to investigate the occurrence of dynamic hyperinflation (DH) in obese asthmatics. Our results demonstrate that obese asthmatics present a higher frequency and intensity of DH than nonobese asthmatics. We also show that physical deconditioning in this population is linearly associated with cardiac (O₂ pulse), respiratory (DH), and peripheral muscle (resistance) limitation. However, multiple linear regression demonstrated that peripheral muscle limitation may explain the exercise limitation in this population.

Mechanisms, measurement and management of exertional dyspnoea in asthma: Number 5 in the Series "Exertional dyspnoea" Edited by Pierantonio Laveneziana and Piergiuseppe Agostoni

Asthma is a heterogeneous condition, with dyspnoea during exercise affecting individuals to a variable degree. This narrative review explores the mechanisms and measurement of exertional dyspnoea in asthma and summarises the available evidence for the efficacy of various interventions on exertional dyspnoea. Studies on the mechanisms of dyspnoea in asthma have largely utilised direct bronchoprovocation challenges, rather than exercise, which may invoke different physiological mechanisms. Thus, the description of dyspnoea during methacholine challenge can differ from what is experienced during daily activities, including exercise. Dyspnoea perception during exercise is influenced by many interacting variables, such as asthma severity and phenotype, bronchoconstriction, dynamic hyperinflation, respiratory drive and psychological factors. In addition to the intensity of dyspnoea, the qualitative description of dyspnoea may give important clues as to the underlying mechanism and may be an important endpoint for future interventional studies. There is currently little evidence demonstrating whether pharmacological or non-pharmacological interventions specifically improve exertional dyspnoea, which is an important area for future research.

Advances in the Evaluation of Respiratory Pathophysiology during Exercise in Chronic Lung Diseases

Dyspnea and exercise limitation are among the most common symptoms experienced by patients with various chronic lung diseases and are linked to poor quality of life. Our understanding of the source and nature of perceived respiratory discomfort and exercise intolerance in chronic lung diseases has increased substantially in recent years. These new mechanistic insights are the primary focus of the current review. Cardiopulmonary exercise testing (CPET) provides a unique opportunity to objectively evaluate the ability of the respiratory system to respond to imposed incremental physiological stress. In addition to measuring aerobic capacity and quantifying an individual's cardiac and ventilatory reserves, we have expanded the role of CPET to include evaluation of symptom intensity, together with a simple "non-invasive" assessment of relevant ventilatory control parameters and dynamic respiratory mechanics during standardized incremental tests to tolerance. This review explores the application of the new advances in the clinical evaluation of the pathophysiology of exercise intolerance in chronic obstructive pulmonary disease (COPD), chronic asthma, interstitial lung disease (ILD) and pulmonary arterial hypertension (PAH). We hope to demonstrate how this novel approach to CPET interpretation, which includes a quantification of activity-related dyspnea and evaluation of its underlying mechanisms, enhances our ability to meaningfully intervene to improve quality of life in these pathologically-distinct conditions.

Dynamic hyperinflation in patients with asthma and exercise-induced bronchoconstriction

BACKGROUND

Little is known about the behavior of operative lung volumes during exercise in patients with asthma and exercise-induced bronchoconstriction (EIB).

OBJECTIVE

To compare the presence of dynamic hyperinflation (DH) in patients with mild asthma with and without EIB and in healthy individuals and to relate the changes in end-expiratory lung volume (EELV) with postexercise airflow reduction.

METHODS

A total of 122 consecutive stable patients (>12 years of age) with mild asthma and 38 controls were studied. Baseline lung volumes were measured, and all patients performed an exercise bronchial challenge. At each minute of exercise, EELV and end-inspiratory lung volume (EILV) were estimated from inspiratory capacity measurements to align the tidal breathing flow-volume loops to within the maximal expiratory curve.

RESULTS

DH was more frequent in patients with asthma and EIB (76%) than in patients with asthma but without EIB (11%) or controls (18%). The EELV increased in patients with asthma and EIB and decreased in patients with asthma without EIB and controls during exercise. In the patients with asthma, the decrease in forced expiratory volume in 1 second after the exercise challenge correlated with age (r = -0.179, P = .05), baseline forced vital capacity (r = 0.255, P = .005), EELV increase (r = 0.447, P < .001), and EILV increase (r = 0.246, P = .007). Age, baseline forced vital capacity, and magnitude of DH were retained as independent predictors of EIB intensity.

CONCLUSION

In patients with asthma and EIB, the development of DH is very frequent and related to the intensity of postexercise bronchoconstriction. This finding could implicate DH in the development of EIB.

The role of inspiratory muscle training in the management of asthma and exercise-induced bronchoconstriction

Asthma is a pathological condition comprising of a variety of symptoms which affect the ability to function in daily life. Due to the high prevalence of asthma and associated healthcare costs, it is important to identify low-cost alternatives to traditional pharmacotherapy. One of these low cost alternatives is the use of inspiratory muscle training (IMT), which is a technique aimed at increasing the strength and endurance of the diaphragm and accessory muscles of respiration. IMT typically consists of taking voluntary inspirations against a resistive load across the entire range of vital capacity while at rest. In healthy individuals, the most notable benefits of IMT are an increase in diaphragm thickness and strength, a decrease in exertional dyspnea, and a decrease in the oxygen cost of breathing. Due to the presence of expiratory flow limitation in asthma and exercise-induced bronchoconstriction, dynamic lung hyperinflation is common. As a result of varying operational lung volumes, due in part to hyperinflation, the respiratory muscles may operate far from the optimal portion of the length-tension curve, and thus may be forced to operate against a low pulmonary compliance. Therefore, the ability of these muscles to generate tension is reduced, and for any given level of ventilation, the work of breathing is increased as compared to non-asthmatics. Evidence that IMT is an effective treatment for asthma is inconclusive, due to limited data and a wide variation in study methodologies. However, IMT has been shown to decrease dyspnea, increase inspiratory muscle strength, and improve exercise capacity in asthmatic individuals. In order to develop more concrete recommendations regarding IMT as an effective low-cost adjunct in addition to traditional asthma treatments, we recommend that a standard treatment protocol be developed and tested in a placebo-controlled clinical trial with a large representative sample.

Activity limitation and exertional dyspnea in adult asthmatic patients: What do we know?

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.

The impact of exercise-induced bronchoconstriction on athletic performance: a systematic review

BACKGROUND

Exercise-induced bronchoconstriction (EIB) describes the phenomenon of transient airway narrowing in association with physical activity. Although it may seem likely that EIB would have a detrimental impact on athletic performance, this has yet to be established.

OBJECTIVES

The aim of this review is to provide a systematic appraisal of the current status of knowledge regarding EIB and exercise performance and to highlight potential mechanisms by which performance may be compromised by EIB.

DATA SOURCES AND STUDY SELECTION

PubMed/Medline and EBSCO databases were searched up to May 2014 using the search parameter: [('exercise' OR 'athlete') AND ('asthma' OR 'bronchoconstriction' OR 'hypersensitivity') AND 'performance']. This search string returned 243 citations. After systematically reviewing all of the abstracts, 101 duplicate papers were removed, with 132 papers excluded for not including an exercise performance outcome measure.

RESULTS

The remaining ten studies that met the initial criteria were included in this review; six evaluated the performance of physically active individuals with asthma and/or EIB while four assessed the effects of medication on performance in a comparable population.

CONCLUSION

The evidence concludes that whilst it is reasonable to suspect that EIB does impact athletic performance, there is currently insufficient evidence to provide a definitive answer.

The role of the small airways in the pathophysiology of asthma and chronic obstructive pulmonary disease

Chronic respiratory diseases, such as asthma and chronic obstructive pulmonary disease (COPD), represent a major social and economic burden for worldwide health systems. During recent years, increasing attention has been directed to the role of small airways in respiratory diseases, and their exact contribution to the pathophysiology of asthma and COPD continues to be clarified. Indeed, it has been suggested that small airways play a distinct role in specific disease phenotypes. Besides providing information on small airways structure and diagnostic procedures, this review therefore aims to present updated and evidence-based findings on the role of small airways in the pathophysiology of asthma and COPD. Most of the available information derives from either pathological studies or review articles and there are few data on the natural history of small airways disease in the onset or progression of asthma and COPD. Comparisons between studies on the role of small airways are hard to draw because both asthma and COPD are highly heterogeneous conditions. Most studies have been performed in small population samples, and different techniques to characterize aspects of small airways function have been employed in order to assess inflammation and remodelling. Most methods of assessing small airways dysfunction have been largely confined to research purposes, but some data are encouraging, supporting the utilization of certain techniques into daily clinical practice, particularly for early-stage diseases, when subjects are often asymptomatic and routine pulmonary function tests may be within normal ranges. In this context further clinical trials and real-life feedback on large populations are desirable.

Breathing exercises for asthma

Educational aims

To summarise the evidence of the role of breathing control approaches in the management of asthma

To provide information on the content of evidence-based breathing exercises programmes

Summary

Asthma is a complex, multi-dimensional condition that affects patients in many ways. Having asthma is inherently stressful and psychological problems are common and associated with poor asthma outcomes. Although most patients in clinical trials can achieve high levels of control with optimised pharmacotherapy, in “real-life” practice, poor control is common, with over-reliance on rescue bronchodilator medication and ongoing symptoms and quality-of-life impairment. Many patients are interested in non-pharmacological treatments to improve asthma control, particularly breathing control exercises but, until recently, the evidence base has been inadequate. The place of breathing exercises has been controversial, partly because some proponents have made exaggerated, implausible claims of effectiveness. Recent evidence, however, has resulted in endorsement of breathing exercises as add-on treatment in asthma in systematic reviews and guidelines.

This review summarises the current evidence of effectiveness of breathing exercises programmes as an adjuvant treatment to pharmacological strategies for people with asthma. The types of breathing training programmes used and the content of effective programmes are discussed. We conclude that patients whose asthma continues to cause symptoms and quality-of-life impairment, despite adequate pharmacological treatment, or who have high bronchodilator use, should be offered access to an effective breathing training programme as a part of holistic, integrated asthma care.

Key points

Asthma is frequently poorly controlled despite effective modern medication

Psychological factors can be as important as physiological ones in affecting symptom perception and disease impact

Breathing exercises can improve patient-reported outcomes and psychological state

Breathing exercises should be offered to all asthma patients with symptoms or impaired quality of life despite standard treatment

The role of small airway disease in asthma

PURPOSE OF REVIEW

This review provides an update on the importance of the peripheral 'small' airways in asthma. As the small airways account for less than 10% of total airway resistance, thus having little impact on standard lung function measures such as forced expiratory volume and peak flow, they have been referred to as the 'silent zone'.

RECENT FINDINGS

The study has revealed that small airway involvement is present in all stages of asthmatic disease, being related to important clinical phenotypes such as nocturnal asthma, exercise-induced asthma, and difficult-to-control asthma, including those with the risk of repeated asthma exacerbations. Uncontrolled small airway inflammation is related to airway remodeling and progression of the disease, with a more rapid decline in the lung function. Moreover, studies on both children and adults have shown that the involvement of the small airways represents a crucial step in asthma development. New tools have been developed and old tools have been refined, providing an opportunity to better understand small airway inflammation and dysfunction.

SUMMARY

Small airway inflammation is present in all stages of asthmatic disease and plays an important role in many key clinical conditions/phenotypes. In order to control the disease, we need to target small airway inflammation, which is not only difficult to reach by standard inhaled medications but also to some extent different. A better understanding of the important role small airways are playing in asthma will show that the 'silent zone' is by far not silent at all.

Factors associated with aerobic fitness in adolescents with asthma

BACKGROUND

In adolescents with asthma, information on factors associated with cardiorespiratory fitness levels is limited. The present study aimed to determine if objectively measured physical activity as well as potential relevant factors such as lung function, asthma exacerbations, use of inhaled corticosteroids or skin fold thickness are associated with direct measurements of peak oxygen uptake (V˙O2peak) in adolescents with asthma.

METHODS

From a nested case-control study at 13-years in the Environment and Childhood Asthma birth cohort study in Oslo, Norway, 86 13-years old adolescents with and 76 without asthma performed maximal running on a treadmill with V˙O2peak measured. The sum of four skin fold thicknesses was recorded, followed by wearing an activity monitor for four consecutive days. Lung function was measured by maximum forced expiratory flow-volume curves and body plethysmography. Asthma exacerbations and use of medication were registered by parental structured interview. Data were analysed using multiple regression analysis.

RESULTS

Vigorous physical activity (coefficients with 95% confidence intervals; 1.73 (0.32, 3.14)) and skin fold thickness -0.35 (-0.41, -0.28)) were significantly associated with V˙O2peak in adolescents with asthma. Neither use of inhaled corticosteroids, lung function nor number of asthma exacerbations was associated with V˙O2peak when taking physical activity and skin fold thickness into account. In the adolescents without asthma only skin fold thicknesses was negatively associated with V˙O2peak -3.5 (-4.1, -2.8).

CONCLUSIONS

V˙O2peak appears to be determined by vigorous physical activity level in Norwegian adolescents with asthma and not by asthma-related factors such as use of inhaled corticosteroids, lung function nor number of asthma exacerbations.

Assessing exercise limitation using cardiopulmonary exercise testing

The cardiopulmonary exercise test (CPET) is an important physiological investigation that can aid clinicians in their evaluation of exercise intolerance and dyspnea. Maximal oxygen consumption ([Formula: see text]) is the gold-standard measure of aerobic fitness and is determined by the variables that define oxygen delivery in the Fick equation ([Formula: see text] = cardiac output × arterial-venous O(2) content difference). In healthy subjects, of the variables involved in oxygen delivery, it is the limitations of the cardiovascular system that are most responsible for limiting exercise, as ventilation and gas exchange are sufficient to maintain arterial O(2) content up to peak exercise. Patients with lung disease can develop a pulmonary limitation to exercise which can contribute to exercise intolerance and dyspnea. In these patients, ventilation may be insufficient for metabolic demand, as demonstrated by an inadequate breathing reserve, expiratory flow limitation, dynamic hyperinflation, and/or retention of arterial CO(2). Lung disease patients can also develop gas exchange impairments with exercise as demonstrated by an increased alveolar-to-arterial O(2) pressure difference. CPET testing data, when combined with other clinical/investigation studies, can provide the clinician with an objective method to evaluate cardiopulmonary physiology and determination of exercise intolerance.

Vital capacity and inspiratory capacity as additional parameters to evaluate bronchodilator response in asthmatic patients: a cross sectional study

Background

Bronchodilator response in patients with asthma is evaluated based on post-bronchodilator increase in forced expiratory volume in one second (FEV₁) and forced vital capacity (FVC). However, the need for additional parameters, mainly among patients with severe asthma, has already been demonstrated.

Methods

The aim of this study was to evaluate the usefulness of vital capacity (VC) and inspiratory capacity (IC) to evaluate bronchodilator response in asthma patients with persistent airflow obstruction. The 43 asthma patients enrolled in the study were stratified into moderate or severe airflow obstruction groups based on baseline FEV₁. All patients performed a 6-minute walk test before and after the bronchodilator (BD). A bipolar visual analogue scale post-BD was performed to assess clinical effect. The correlation between VC and IC and clinical response, determined by visual analogue scale (VAS) and 6-minute walk test (6MWT), was investigated.

Results

Patients in the severe group presented: 1) greater bronchodilator response in VC (48% vs 15%, p = 0.02), 2) a significant correlation between VC variation and the reduction in air trapping (Rs = 0.70; p < 0.01), 3) a significant agreement between VC and VAS score (kappa = 0.57; p < 0.01). There was no correlation between IC and the reduction in air trapping or clinical data.

Conclusions

VC may be a useful additional parameter to evaluate bronchodilator response in asthma patients with severe airflow obstruction.

Asthma and obesity: a known association but unknown mechanism

The obese asthma phenotype is an increasingly common encounter in our clinical practice. Epidemiological data indicate that obesity increases the prevalence and incidence of asthma, and evidence that obesity precedes the development of asthma raises the possibility of a causal association. Obese patients with asthma experience more symptoms and increased morbidity compared with non-obese asthma patients. Despite more than a decade of research into this association, the exact mechanisms that underlie the interaction of obesity with asthma remain unclear. It is unlikely that the asthma-obesity association is simply due to comorbidities such as obstructive sleep apnoea or gastroesophageal reflux disease. Although inflammatory pathways are purported to play a role, there is scant direct evidence in humans that systemic inflammation modulates the behaviour of the asthmatic airway or the expression of symptoms in the obese. The role of non-eosinophilic airway inflammation also requires further study. Obesity results in important changes to the mechanical properties of the respiratory system, and these obesity-related factors appear to exert an additive effect to the asthma-related changes seen in the airways. An understanding of the various physiological perturbations that might be contributing to symptoms in obese patients with asthma will allow for a more targeted and rational treatment approach for these patients.

Effect of inspiratory muscle training on exercise tolerance in asthmatic individuals

PURPOSE

The aim of this study was to determine the effects of inspiratory muscle training (IMT) on exercise tolerance, inspiratory muscle fatigue, and the perception of dyspnea in asthmatic individuals.

METHODS

Using a matched double-blind placebo-controlled design, 15 clinically diagnosed asthmatic individuals underwent either 6 wk of IMT (n = 7) consisting of 30 breaths twice daily at 50% maximum inspiratory pressure (PI max) or sham-IMT (placebo; PLA, n = 8) consisting of 60 breaths daily at 15% PI max. Time to the limit of exercise tolerance (Tlim) was assessed using constant-power output (70% peak power) cycle ergometry. Inspiratory muscle fatigue was determined by comparing the pre- to postexercise reduction in PI max. Dyspnea during the Tlim test was evaluated at 2-min intervals using the Borg CR-10 scale.

RESULTS

There were no significant changes (P > 0.05) in Tlim, inspiratory muscle fatigue, or perception of dyspnea in the PLA group after the intervention. In contrast, in the IMT group, PI max increased by 28%, and Tlim increased by 16% (P < 0.05). Dyspnea during exercise was also reduced significantly by 16% (P < 0.05). The exercise-induced fall in PI max was reduced from 10% before IMT to 6% after IMT (P < 0.05), despite the longer Tlim. Pulmonary function remained unchanged in both the IMT and PLA groups.

CONCLUSIONS

These data suggest that IMT attenuates inspiratory muscle fatigue, reduces the perception of dyspnea, and increases exercise tolerance. These findings suggest that IMT may be a helpful adjunct to asthma management that has the potential to improve participation and adherence to exercise training in this group. However, the perception of breathlessness is also an important signal of bronchoconstriction, and thus, caution should be exercised if this symptom is abnormally low.

Effects of inhaled mometasone furoate on growth velocity and adrenal function: a placebo-controlled trial in children 4-9 years old with mild persistent asthma

OBJECTIVE

To assess the effects of long-term mometasone furoate delivered via a dry powder inhaler (MF-DPI) on growth velocity and hypothalamic-pituitary-adrenal axis function in children with asthma.

STUDY DESIGN

Children aged 4-9 years with asthma (n = 187) were randomized to MF-DPI 100 μg (delivered dose; actuated dose is 110 μg) once daily in the morning (QD AM), 100 μg twice daily (BID), 200 μg QD AM, or placebo for 52 weeks followed by a 3-month follow-up period. The primary outcome was growth velocity calculated from stadiometric heights recorded at each visit. Secondary outcomes included serum and 12-h urinary cortisol, serum osteocalcin, and urinary N-telopeptide.

RESULTS

MF-DPI 100 μg QD AM treatment did not significantly affect growth velocity compared with placebo (-0.10 ± 0.31 cm/y, p = 0.76). When the effect of a total daily dose of 200 μg MF-DPI on growth velocity was examined, no significant effect was demonstrated for MF-DPI 100 μg BID compared with placebo (-0.64 ± 0.39 cm/y, p = 0.10), although the change in mean growth velocity with MF-DPI 200 μg QD AM reached statistical significance (-0.70 ± 0.29 cm/y, p = 0.02). The effects of all examined doses of MF-DPI on mean plasma cortisol levels were similar to cortisol changes seen in the placebo group, suggesting an absence of drug-related effects. No differences in 12-h urinary cortisol or other outcomes were observed between groups.

CONCLUSIONS

One year of treatment with a total daily dose of 100 μg of MF-DPI in the morning resulted in no significant difference, whereas a total daily dose of 200 μg of MF-DPI was associated with some changes in growth velocity when compared with placebo. The differences in growth velocity, and the absence of drug-related cortisol effects, support the use of a total daily dose of 100 μg of MF-DPI in children aged 4-9 years with mild persistent asthma.

The role of breathing training in asthma management

PURPOSE OF REVIEW

There is considerable public interest in the use of breathing modification techniques in the treatment of asthma. Surveys suggest many people with asthma use them, often without the knowledge of their medical attendants. Extravagant claims have been made about the effectiveness of some techniques, resulting in scepticism from orthodox clinicians. The evidence supporting breathing training for asthma was previously weak, and limited by the small size and methodological limitations of published research.

RECENT FINDINGS

The evidence base for the effectiveness of breathing training has recently improved, with reports from several larger and more methodologically robust controlled trials. These trials are reviewed in this study, and the findings placed in context. Trials have investigated a variety of breathing training programmes delivered by different therapists in different ways. All incorporate some instruction in breathing pattern, usually focusing on slow, regular, nasal, abdominal breathing and reduced ventilation, with patients instructed to practise exercises at home and when symptomatic.

SUMMARY

Current evidence suggests that breathing training programmes can be effective in improving patient-reported outcomes such as symptoms, quality of life and psychological impact; and may reduce the use of rescue bronchodilator medication. There is little evidence that airways physiology, hyper-responsiveness or inflammation is affected by such training. The optimal way of providing breathing training within the context of routine asthma care is still uncertain.

Long-term safety of mometasone furoate administered via a dry powder inhaler in children: Results of an open-label study comparing mometasone furoate with beclomethasone dipropionate in children with persistent asthma

Background

To assess the long-term pediatric safety of 2 doses of mometasone furoate administered via a dry powder inhaler (MF-DPI) for mild-to-moderate persistent asthma and compare them with that of beclomethasone dipropionate administered via a metered dose inhaler (BDP-MDI) in the treatment of persistent asthma. Both MF-DPI doses tested are twice the approved pediatric dosage of 100 μg once-daily (QD) for children aged 4–11 years.

Methods

Children (N = 233) aged 4–11 years were randomized to 52 weeks of treatment with MF-DPI 200 μg QD AM, MF-DPI 100 μg twice daily (BID), or BDP-MDI 168 μg BID. Patients had used inhaled corticosteroids (ICSs) daily for ≥ 30 days before the screening visit and were on stable ICS doses for ≥ 2 weeks before screening. The primary safety variable was the incidence of adverse events. Secondary safety variables were laboratory tests (including cortisol concentrations), vital signs, and physical examination.

Results

The incidence of adverse events was similar in all 3 treatment groups. The most frequently reported adverse event was upper respiratory tract infection, reported by 47%–49% of the MF-DPI-treated patients and 51% of the BPD-treated patients. Most adverse events were considered unrelated to study drug. The most frequently reported related adverse events were headache (MF-DPI 200 μg QD AM, 8%; MF-DPI 100 μg BID, 4%; BDP-MDI 168 μg BID, 2%) and oral candidiasis (4% in each treatment group). No clinically relevant changes in laboratory values, including plasma cortisol, vital signs, or physical examinations were noted in any treatment group.

Conclusion

Both MF-DPI doses were well tolerated, with no unusual or unexpected adverse events or safety concerns, and had a similar adverse event profile to that of BDP-MDI 168 μg BID.

Mometasone furoate dry-powder inhaler for the control of persistent asthma

Mometasone furoate dry-powder inhaler (MF-DPI) is an inhaled corticosteroid (ICS) used for the treatment of persistent asthma in patients aged >or= 12 years. MF-DPI has low systemic bioavailability and high glucocorticoid receptor affinity compared with most other ICSs and modifies inflammatory mediators involved in the pathogenesis of asthma. MF-DPI, unlike other available ICSs, is approved for initiation as a once-daily in the afternoon (q.d. PM) regimen. Studies show that MF-DPI 200 or 400 microg q.d. PM treatment significantly improves lung function and symptom control in patients with mild, moderate or severe asthma. MF-DPI 400 microg q.d. PM is reported to be equivalent to fluticasone propionate 250 microg b.i.d. and beclometasone dipropionate 168 microg b.i.d. and more efficacious than budesonide 400 microg, b.i.d. or q.d. MF-DPI is generally well tolerated, with minimal effects on the hypothalamic-pituitary-adrenal axis.

Responsiveness of patient-reported breathlessness during exercise in persistent asthma

BACKGROUND

The purpose of the study was to examine the responsiveness of a computerized system whereby the patient reports spontaneously any change in the intensity of breathlessness during exercise. The hypotheses were that hypercapnia would increase and hyperoxia would decrease the slope of power production-breathlessness ratings compared with a control condition during cycle ergometry.

METHODS

Thirty adult subjects (15 women and 15 men) with persistent asthma (mean [+/- SD] FEV(1)/FVC ratio, 57 +/- 10%) completed an initial familiarization visit and three study visits. All subjects inhaled two puffs of albuterol (180 microg) in order to standardize lung function prior to exercise. At visits 2 to 4, subjects breathed one of the three gas mixtures administered in a random order while performing a ramp exercise test. The experimental conditions were as follows: hypercapnia (5% carbon dioxide); hyperoxia (40% oxygen); and control (room air).

RESULTS

Lung function was the same before and after exercise with the three experimental conditions. With hypercapnia, peak ventilation was increased, peak oxygen consumption, and power production were reduced, the slope of power-breathlessness was increased, and 25 patients (83%) reported breathlessness as the limiting symptom. With hyperoxia, peak ventilation was decreased, peak power production and the slope of power-breathlessness were unchanged, and 16 patients (53%) reported leg discomfort as the limiting symptom.

CONCLUSIONS

Breathing 5% carbon dioxide altered physiologic responses and the slope of power production-breathlessness during exercise. The responses to hyperoxia were inconsistent. The continuous method for patient-reported breathlessness was responsive to hypercapnia, but not to hyperoxia, during incremental exercise.

[Exercise test for asthmatic children. For whom? What indications?]

Asthma in children is not the most important indication for an exercise test. However, one might recommend a cardiopulmonary exercise test systematically in the follow-up of patients with severe asthma when there is persistent bronchial obstruction, when an asthmatic child complains of dyspnoea on exertion, or when the child's physical activity is limited. This test could be used to assess exercise tolerance, ventilatory adaptations, and the need for exercise training. Follow-up and evaluation of this training could be through a field exercise test (shuttle test or walk test). Moreover, the diagnosis of childhood asthma is frequently based only on symptoms suggestive of exercise-induced asthma. When the clinical features or a bronchodilatator test are not diagnostic, analysis of symptoms occurring during an exercise test can establish the diagnosis. The exercise test is thus a method that provides the time and intensity necessary to trigger exercise-induced bronchospasm.

Expiratory flow limitation in patients with pleural effusion

BACKGROUND

Expiratory flow limitation (EFL) is one of the main mechanisms contributing to dyspnea in patients with chronic obstructive pulmonary disease but has not been explored in patients with pleural effusion.

OBJECTIVES

It was the aim of this study to determine whether patients with pleural effusion exhibit EFL and to investigate the effect of therapeutic thoracentesis on EFL.

PATIENTS AND METHODS

The study was performed on 21 patients with pleural effusion who were subjected to thoracentesis and measurement of pleural pressure (PP). Spirometry and estimation of flow limitation by the negative expiratory pressure technique were performed before and after thoracentesis.

RESULTS

Statistically significant differences were observed in all spirometric parameters. No correlation between the increase in lung volumes and flows and any of the aspirated fluid parameters was observed. Before thoracentesis, 14 out of 21 patients were flow limited, compared with 7 patients after thoracentesis (chi(2) = 6.151, p = 0.013). Mean values of flow limitation before and after thoracentesis differed significantly. The decrease in flow limitation did not correlate with the increase in the spirometric parameters, the aspirated fluid volume or PP decrease.

CONCLUSIONS

In the majority of patients with pleural effusion, flow limitation improves after thoracentesis. Flow limitation may be a contributing factor to the sensation of dyspnea in these patients.

Treatment and outcomes in patients with asthma and allergic rhinitis in the United kingdom

BACKGROUND

Since allergic rhinitis in asthma patients is associated with worse asthma control, the treatment of the comorbid condition may improve outcomes.

METHODS

A 1-year retrospective study using the UK Mediplus database (2001-2004) included asthmatic patients aged 15-55 with allergic rhinitis. Patients starting therapy based on the Global Initiative for Asthma guidelines, defined as an increase in inhaled corticosteroids (high-dose inhaled corticosteroids, hdICS), or the addition of montelukast (ICS+MON) or long-acting beta-agonists (ICS+LABA) to ICS, were studied. Univariable and multiple logistic regressions evaluated asthma-related outcomes.

RESULTS

Among 2,596 asthma and allergic rhinitis patients, 83.2% initiated ICS+LABA, 12.1% hdICS and 4.7% ICS+MON. The mean age was 34 years and 60% were female. ICS+MON patients had more moderate-severe asthma (p = 0.04). Approximately 84% of the ICS+LABA patients experienced an asthma control failure compared to 50% in the other groups (p < 0.0001). The proportions of patients requiring treatment change were 73.8, 22 and 27.3% in the ICS+LABA, hdICS and ICS+MON groups, respectively (p = 0.001). Asthma-related resource use was similar among all groups. The ICS+MON group received fewer mean prescriptions for oral corticosteroids (p = 0.024) than the other groups (p = 0.026).

CONCLUSIONS

In asthma and allergic rhinitis, treatment with ICS+MON or hdICS was associated with lower rates of asthma control failure and fewer treatment changes than the ICS+LABA group. MON users also required fewer oral corticosteroids.

Relationship between peak expiratory flow rate and shoulders posture in healthy individuals and moderate to severe asthmatic patients

INTRODUCTION

Asthma overloads respiratory muscles causing changes in posture.

OBJECTIVES

To evaluate shoulder position in asthmatics and its correlation to the peak expiratory flow rate (PEFR).

METHODS

A cross-sectional study involving 19 asthmatics (study group) and 20 healthy volunteers (control group). Assessment of PEFR was used to determine airway obstruction. Shoulder position was quantified as the ratio between the front and back measurements, in centimeters, of the distance between the two outermost points of each scapula. Shoulder position measurement (SPM) ratio data from both groups were compared and correlated to PEFR.

RESULTS

The asthmatics presented lower PEFR (279 +/- 64 L/min) and SPM (0.88: range 0.83-0.9) than did control subjects (555 +/- 100 L/min and 0.97: range 0.95-1, respectively) (p < 0.001). There was a correlation between PEFR and SPM (asthmatics r = 0.8; controls r = 0.5).

CONCLUSION

Determining SPM ratios allowed us to identify those postural alterations that correlated with pulmonary function in asthmatics and in healthy individuals. Further investigation is needed before SPM can be used as a tool for clinical evaluation of asthma patients.