Mechanisms of dyspnoea and its language in patients with asthma

Severity and phenotypes of dyspnea in asthma: Impact of comorbidities

BACKGROUND

Dyspnea is a common but non-specific symptom of asthma, which in particular may be related to anxiety and hyperventilation syndrome, two frequent comorbidities of asthma.

METHODS

We conducted a prospective multicentric cohort study in dyspneic asthmatic adults. Dyspnea was assessed using the Multidimensional Dyspnea Profile questionnaire. We described the sensory (QS) and affective (A2) domains of dyspnea and investigated the effect of poor asthma control, hyperventilation and anxiety on each dimension at baseline and after 6 months.

RESULTS

We included 142 patients (65.5% women, age: 52 years). Dyspnea was severe and predominated on its sensory domain (median QS: 27/50; A2: 15/50). Uncontrolled asthma (ACQ≥1.5), hyperventilation symptoms (Nijmegen≥23) and anxiety (HAD-A≥10) were present in 75%, 45.7% and 39% of cases, respectively. Hyperventilation symptoms were associated with higher QS and A2 scores: QS at 28.4(10.7) vs. 21.7(12.8) (p = 0.001) and A2 at 24(14) vs. 11.3(11) (p < 0.001) in patients with vs. without hyperventilation symptoms. Anxiety was only associated with increased A2 (27(12.3) vs. 10.9(11), p < 0.001). At 6 months, QS and A2 decreased of 7 and 3 points, respectively, in relation with changes in ACQ-6 and Nijmegen scores as well as the HAD-A score for A2.

CONCLUSION

In breathless asthmatics, dyspnea is severe and worsened but differentially modulated by hyperventilation symptoms and anxiety. A multidimensional phenotyping of dyspnea in asthmatics could be useful to understand its origins and personalize treatment.

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.

Physical training in adults with asthma: An integrative approach on strategies, mechanisms, and benefits

Asthma is a chronic airway disease characterized by airflow limitation and respiratory symptoms associated with chronic airway and systemic inflammation, bronchial hyperreactivity (BHR), and exercise-induced bronchoconstriction (EIB). Asthma is a heterogeneous disease classified according to distinct airway and systemic inflammation. Patients commonly present with several comorbidities, including anxiety, depression, poor sleep quality, and reduced physical activity levels. Individuals with moderate to severe asthma often have more symptoms and difficulty achieving adequate clinical control, which is associated with poor quality of life, despite proper pharmacological treatment. Physical training has been proposed as an adjunctive therapy for asthma. Initially, it was suggested that the effect of physical training might be attributed to the improved oxidative capacity and reduced production of exercise metabolites. However, in the last decade, there has been evidence that aerobic physical training promotes anti-inflammatory effects in asthma patients. Physical training improves BHR and EIB, asthma symptoms, clinical control, anxiety, and depression levels, sleep quality, lung function, exercise capacity, and dyspnea perception. Furthermore, physical training reduces medication consumption. The most commonly used exercise strategies are moderate aerobic and breathing exercises; however, other techniques, such as high-intensity interval training, have shown promising effects. In the present study, we reviewed the strategies and beneficial effects of exercise on clinical and pathophysiological asthma outcomes.

Multidimensional breathlessness response to exercise: Impact of COPD and healthy ageing

This study compared the multidimensional breathlessness response to incremental cardiopulmonary cycle exercise testing (CPET) in people with chronic obstructive pulmonary disease (COPD; n = 14, aged 69 ± 9 years, forced expiratory volume in 1-sec = 54 ± 16 % predicted) and healthy older (OA) (n = 35, aged 68 ± 5 years) and younger (YA) (n = 19, aged 28 ± 8 years) adults. Participants performed CPET and successively rated overall breathlessness intensity, unsatisfied inspiration, breathing too shallow, work/effort of breathing, and breathlessness-related unpleasantness, fear, and anxiety using the 0-10 Borg scale. At any given percent predicted peak minute ventilation, people with COPD rated all breathlessness sensations higher than OA and YAs, who were similar. Most between group differences disappeared when examined in relation to inspiratory reserve volume, except people with COPD reported higher levels of unsatisfied inspiration and breathing too shallow (vs YA), and breathlessness-related fear and anxiety (vs OA and YAs). Multidimensional ratings of breathlessness sensations during CPET provides further insight into differences in exertional symptom perceptions among people with COPD and without COPD.

Anxiety in asthma: a systematic review and meta-analysis

BACKGROUND

Background: Growing evidence from observational studies indicates a high prevalence of anxiety in asthma. However, prevalence rates of coexisting anxiety symptoms and comorbid anxiety disorders vary widely across studies. We aimed to evaluate the associations between anxiety and asthma and provide more precise comorbidity estimates.

METHODS

We systematically reviewed the literature from case-controlled studies and conducted a meta-analysis to evaluate the pooled prevalence estimates and risks of anxiety symptoms and anxiety disorders in asthma individuals. Screening, data extraction, and quality assessment were undertaken following PRISMA guidelines for preferred reporting of systematic reviews and meta-analysis. A random-effects model was used to calculate pooled prevalence rates. Meta-analysis was conducted using Review Manager 5.3. Multiple databases including PubMed, ScienceDirect, PsychINFO, and PsycARTICLES were searched for publications before 1 December 2019. The review protocol was registered on PROSPERO (ref: CRD42020176028).

RESULTS

In total, 19 studies involving 106813 participants were included. The pooled prevalence of anxiety symptoms and anxiety disorders in individuals with asthma was 0.32 (95% CI 0.22-0.43) and 0.24 (95% CI 0.13-0.41), respectively. The risks of coexisting anxiety symptoms and comorbid anxiety disorders were significantly higher in asthma patients than in non-asthma controls indicated by OR 1.89 (95% CI 1.42-2.52; Z = 4.37; p < 0.001) and OR 2.08 (95% CI 1.70-2.56; Z = 6.97; p < 0.001), respectively. Anxiety symptoms and anxiety disorders occur at increased frequency among patients with asthma.

CONCLUSIONS

Our findings highlight the need for appropriate assessments for these comorbid conditions, which may help to identify a subgroup of patients who might benefit from interventions designed to reduce anxiety and enhance the quality of life.

Effect of age on exercise-induced bronchoconstriction in children and adolescents with asthma

OBJECTIVE

The relationship between exercise-induced bronchoconstriction (EIB) and exertional dyspnea in children and adolescents is yet to be fully established. This study examined whether indicators of fractional exhaled nitric oxide (FeNO), forced expiratory volume in 1 s (FEV₁) percent predicted at baseline, and dyspnea are useful for predicting children and adolescents with EIB.

METHODS

We enrolled 184 children and adolescents diagnosed with asthma (mean age 11.2 years); participants were divided into two groups according to age (12 years) and were subjected to a 6-min exercise challenge test. Lung function tests and modified Borg scale scores were used to examine perceptions of dyspnea at 0, 5 and 15 min after exercise.

RESULTS

Among children, the maximum percentage drop in FEV₁ after exercise correlated significantly with FeNO (adjusted β = 2.3, P < 0.001) and with the perception of dyspnea at 5 min after exercise (adjusted β = 1.9, P < 0.001). Among adolescents, the maximum percentage drop in FEV₁ correlated with FeNO (adjusted β = 2.7, P = 0.007) and with lung function (FEV₁, percent predicted; adjusted β = -0.28, P = 0.006). Children with EIB had significantly stronger dyspnea after exercise than did children without EIB. Adolescents even without EIB may experience more exertional dyspnea than children without EIB.

CONCLUSIONS

Overall, our findings indicated that EIB was associated with FeNO and exertional dyspnea in asthmatic children. By contrast, EIB was associated with FEV₁ percent predicted at baseline and FeNO but not with exertional dyspnea in asthmatic adolescents.

Factors associated with discrepancies between poor dyspnea perception and abnormal lung function in 65 asthmatic patients

Background

Dyspnea is a subjective symptom of asthma whose perception is characterized by an interindividual variability. Poor dyspnea perception is usually associated with increased risk of exacerbation and may lead to inappropriate asthma management and under-treatment. We sought to identify factors associated with discrepancies between poor dyspnea perception and abnormal lung function in patients with moderate persistent asthma.

Methodology

65 patients, who attended their scheduled follow-up pulmonology consultation at Ibn Sina Hospital (Rabat - Morocco), underwent interrogation including modified Medical Research Council (mMRC) scale for dyspnea, physical examination and spirometry. Two groups, those with mMRC < 2 (poor dyspnea perceivers) and those with mMRC scale ≥ 2 were compared.

Results

Poor dyspnea perception was found in 21 patients (32.3%). Associated factors were male sex (p : 0.03), low socio-economic income (p : 0.01), an onset of symptoms greater than 10 years (p : 0.01), BMI ≥ 25 Kg/m2 (p : 0.04) and depression (p : 0.04).

Conclusion

The results revealed factors significantly associated with poor dyspnea perception despite an obstructive ventilatory disorder. These factors could usefully be considered to successfully manage asthma as well as the regular prescription of an objective test like spirometry.

Pulmonary Vascular Disease and Cardiopulmonary Exercise Testing

Cardiopulmonary exercise testing (CPET) is of great interest and utility for clinicians dealing Pulmonary Hypertension (PH) in several ways, including: helping with differential diagnosis, evaluating exercise intolerance and its underpinning mechanisms, accurately assessing exertional dyspnea and unmasking its underlying often non-straightforward mechanisms, generating prognostic indicators. Pathophysiologic anomalies in PH can range from reduced cardiac output and aerobic capacity, to inefficient ventilation, dyspnea, dynamic hyperinflation, and locomotor muscle dysfunction. CPET can magnify the PH-related pathophysiologic anomalies and has a major role in the management of PH patients.

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.

Effect of a combined exercise program on physical fitness, lung function, and quality of life in patients with controlled asthma and exercise symptoms: A randomized controlled trial

BACKGROUND

Asthmatic patients may benefit from exercise training, although the effects of a combined aerobic and resistance training program are still poorly investigated in children and adolescents.

OBJECTIVE

To analyze the effects of a combined exercise training (resistance and aerobic) program on aerobic fitness, lung function, asthma control and quality of life in a group of mild-moderate asthmatic children with exercise symptoms.

METHODS

This was a 12-week randomized controlled trial including children and adolescents diagnosed with mild-moderate asthma and presenting exercise-induced symptoms. The intervention group (IG) performed the exercise training (resistance and aerobic) 3 days/week, for 60 minutes. The control group (CG) followed routine clinical orientations. The main outcomes were cardiorespiratory fitness, muscle strength, lung function, quality of life, asthma control, and functional tests after 3 months of the intervention.

RESULTS

Fifty-three patients (IG = 25 and CG = 28) with a mean age of 11.5 ± 2.6 years were included. No significant differences were found between groups regarding lung function, asthma control, quality of life, and functional tests. Ventilatory equivalent for oxygen consumption at ventilatory threshold (P = .025; ηp2  = 0.083), peak oxygen consumption (P = .008; ηp2  = 0.116) and test duration (P = .014; ηp2  = 0.1) presented greater improvements in the IG. In addition, improvements were observed in leg press (P < .001; ηp2  = 0.36), hamstring curl (P = .001; ηp2  = 0.217), high row (P = .003; ηp2  = .167), low row (P = .009; ηp2  = 0.128) and quadriceps leg extension (P = .015; ηp2  = 0.108) in the IG.

CONCLUSION

Combined exercise training (resistance and aerobic) improved cardiorespiratory fitness and muscle strength in children and adolescents with controlled asthma and exercise symptoms.

Health Services Utilization Is Increased in Poor Perceivers of Bronchoconstriction and Hyperinflation in Asthma

BACKGROUND

Impaired symptom perception is often listed as a risk factor for life-threatening asthma, but there is limited evidence to support this.

OBJECTIVE

We aimed to determine whether impaired perception of bronchoconstriction (BC) and/or dynamic hyperinflation (DH) are risk factors for severe asthma exacerbations.

METHODS

In this prospective cohort study, individuals with asthma underwent high-dose methacholine challenge testing. Changes in forced expiratory volume in 1 second (FEV₁) (% predicted) and inspiratory capacity (IC) (% predicted) were measured to assess the degree of BC and DH, respectively, during high-dose methacholine bronchoprovocation. Participants rated dyspnea intensity during testing and were categorized as poor, normal, and over perceivers of BC and DH based on perception scores at standardized changes (20%, 30%, and 40%) in FEV₁ (% predicted) and IC (% predicted). We compared the rates of severe asthma exacerbations (defined as one of emergency department [ED] visit or hospitalization) between groups, using Ontario's administrative health databases.

RESULTS

Poor perceivers had higher rates of ED visits and hospitalizations as compared with normal perceivers at 4 of 6 threshold decreases in FEV₁ and IC studied. Poor perceivers of severe DH had a 6-fold increase in asthma exacerbations (odds ratio, 5.7; 95% confidence interval, 1.31-25.03).

CONCLUSIONS

Health services utilization is increased in individuals with asthma who have poor perception of BC and DH. Poor perceivers of severe DH appear to be at the highest risk of exacerbations.

The therapeutic effects of bronchial thermoplasty evaluated by cardiopulmonary exercise testing : a case series

Bronchial thermoplasty (BT) had been reported to improve the symptoms of severe asthma. However, the exertional responses of BT based on the mechanisms have not been elucidated. A 57-year-old man and a 60-year-old woman underwent BT due to intractable severe asthma. We evaluated the therapeutic effects of BT using cardiopulmonary exercise testing (CPET). After BT, the exercise time during CPET substantially prolonged reducing exertional dyspnea in the former (good), but not in the latter (poor). In the good responder, the high air remaining in the lung after expiration (i.e., inspiratory tidal volume minus expiratory tidal volume) during CPET decreased after BT. In contrast, in the poor responder, the high air remaining after expiration during exercise was not obtained before BT. Further investigations are necessary to confirm that the presence or absence of the exertional wasted ventilation on CPET may be informative to evaluate the therapeutic effects of BT. J. Med. Invest. 67 : 386-390, August, 2020.

Intensity and quality of exertional dyspnoea in patients with stable pulmonary hypertension

Dynamic hyperinflation is observed during exercise in 60% of patients with clinically stable pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH), intensifying exertional dyspnoea. The impact of dynamic changes in respiratory mechanics during exercise on qualitative dimensions of dyspnoea in these patients has not been evaluated.

26 patients (PAH n=17; CTEPH n=9) performed an incremental symptom-limited cycle exercise test. Minute ventilation (V′E), breathing pattern, operating lung volumes and dyspnoea intensity were assessed throughout exercise. Dyspnoea quality was serially assessed during exercise using a three-item questionnaire (dyspnoea descriptors). The inflection point of tidal volume (VT) relative to V′E was determined for each incremental test. Changes in inspiratory capacity during exercise defined two groups of patients: hyperinflators (65%) and non-hyperinflators (35%). Multidimensional characterisation of dyspnoea was performed after exercise using the Multidimensional Dyspnea Profile.

In hyperinflators, inspiratory capacity decreased progressively throughout exercise by 0.36 L, while remaining stable in non-hyperinflators. The “work/effort” descriptor was most frequently selected throughout exercise in both types of patients (65% of all responses). At the VT/V′E inflection, work/effort plateaued while “unsatisfied inspiration” descriptors became selected predominantly only in hyperinflators (77% of all responses). In the affective domain, the emotion most frequently associated with dyspnoea was anxiety.

In pulmonary hypertension patients who develop hyperinflation during exercise, dyspnoea descriptors referring to unsatisfied inspiration become predominant following the VT/V′E inflection. As these descriptors are generally associated with more negative emotional experiences, delaying or preventing the VT/V′E inflection may have important implications for symptom management in patients with pulmonary hypertension.

Winter Exercise Reduces Allergic Airway Inflammation: A Randomized Controlled Study

Background: Physical exercise is often recommended as additional treatment for people suffering from allergic rhinitis and/or asthma, but less is known about the specific effects of recreational winter outdoor exercise on allergic airway inflammation. Methods: We performed a longitudinal, randomized controlled intervention study to investigate the effects of recreational winter exercise on allergic airway inflammation, quality of life, spirometry and cardiorespiratory fitness in adults suffering from allergic rhinitis and/or asthma. The exercise group participated in a ten-day winter sports program. The control group did not receive any intervention. Results: A significant improvement of fractional oral exhaled nitric oxide (FeNO; p = 0.008, day 10) and a significant decrease in FeNO after a single 4 h hiking tour (p < 0.001, time effect) were observed for the exercise group. The nasal eosinophilic cell count revealed a short-term reduction (p = 0.021, treatment effect) in the exercise group and for the visual analogue scale sustainable improvements in allergic symptoms (p < 0.001, day 60) were found. No adverse effects of outdoor winter exercise were observed. Conclusion: Recreational winter exercise at moderately cold temperatures reduces allergic airway inflammation measured as FeNO, nasal eosinophilic cell count and induces sustainable improvements in allergic symptoms.

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.

Improvement of exertional dyspnea and breathing pattern of inspiration to expiration after bronchial thermoplasty

Background

Bronchial thermoplasty (BT) is a bronchoscopic treatment that can ameliorate the symptoms of severe asthma. However, little is known about the mechanism by which BT improves exertional dyspnea without significantly changing the resting pulmonary function in asthmatics. To understand the mechanism, cardiopulmonary variables were investigated using cardiopulmonary exercise testing (CPET) in a patient with severe asthma before and after BT.

Case presentation

A 57-year-old Japanese man visited our hospital for consultation of the intractable asthma, which we managed with three treatment sessions of BT. Comparison of the findings pre-BT and at 1 year after BT demonstrated that (1) the resting tests for respiration showed no improvement in forced expiratory volume in 1 s, but the forced oscillation technique showed decreases in both inhalation and exhalation respiratory resistance values, and (2) the CPET results showed (i) improvement in exertional dyspnea, exercise endurance, and arterial oxygen saturation at the end of exercise; (ii) that the expiratory tidal volume exceeded the inspiratory tidal volume during exercise, which implied that a sufficient exhalation enabled longer inspiratory time and adequate oxygen absorption; and (iii) that an increase in respiratory frequency could be prevented throughout exercise.

Conclusions

This case report described a novel mechanism of BT in improving exertional dyspnea and exercise duration, which was brought about by ventilatory improvements related to the breathing pattern of inspiration to expiration.

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

Subjective responses to sprint interval exercise in adults with and without Exercise-induced bronchoconstriction

OBJECTIVE

Little is known of the subjective response to exercise that involves short "all out" bursts of effort, separated by recovery periods (sprint interval exercise (SPRINT)) among adults with exercise-induced bronchoconstriction (EIBC). The purpose of this study was to compare subjective responses to SPRINT and moderate intensity continuous exercise (MOD) among adults with EIBC, and to compare these responses between adults with EIBC and those without EIBC.

METHODS

Eight adults (22.3 ± 3.0 years) with EIBC, and eight adults (22.3 ± 3.0 years) without EIBC completed a SPRINT (4 × 30 second sprints separated by 4.5 minutes of active recovery) and MOD (20 minutes at 65% peak power output) session in random order. Self-reported affect, perceived breathlessness, and perceived exertion were recorded throughout exercise using validated scales. Enjoyment was assessed following exercise.

RESULTS

Differences between SPRINT and MOD were observed such that affect and perceived breathlessness were worse during the initial stages of SPRINT than MOD; however, differences disappeared by the end of exercise. Enjoyment was similar for SPRINT and MOD in the EIBC group (SPRINT: 72.9 ± 20.0 vs. MOD: 79.5 ± 20.5, p = 0.25), and between groups for SPRINT and MOD.

CONCLUSIONS

Perceived breathlessness may impact affect during the early stages of exercise among those with EIBC. Post-exercise enjoyment appears to be similar between SPRINT and MOD. Future research is needed to better understand the relationship between ventilation patterns, exercise intensity, and enjoyment of exercise among those with EIBC.

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.

Addressing unmet needs in understanding asthma mechanisms: From the European Asthma Research and Innovation Partnership (EARIP) Work Package (WP)2 collaborators

Asthma is a heterogeneous, complex disease with clinical phenotypes that incorporate persistent symptoms and acute exacerbations. It affects many millions of Europeans throughout their education and working lives and puts a heavy cost on European productivity. There is a wide spectrum of disease severity and control. Therapeutic advances have been slow despite greater understanding of basic mechanisms and the lack of satisfactory preventative and disease modifying management for asthma constitutes a significant unmet clinical need. Preventing, treating and ultimately curing asthma requires co-ordinated research and innovation across Europe. The European Asthma Research and Innovation Partnership (EARIP) is an FP7-funded programme which has taken a co-ordinated and integrated approach to analysing the future of asthma research and development. This report aims to identify the mechanistic areas in which investment is required to bring about significant improvements in asthma outcomes.

Exertional Dyspnoea in Chronic Respiratory Diseases: From Physiology to Clinical Application

Dyspnoea is a complex, highly personalized and multidimensional sensory experience, and its underlying cause and mechanisms are still being investigated. Exertional dyspnoea is one of the most frequently encountered symptoms of patients with cardiopulmonary diseases, and is a common reason for seeking medical help. As the symptom usually progresses with the underlying disease, it can lead to an avoidance of physical activity, peripheral muscle deconditioning and decreased quality of life. Dyspnoea is closely associated with quality of life, exercise (in)tolerance and prognosis in various conditions, including chronic obstructive pulmonary disease, heart failure, interstitial lung disease and pulmonary hypertension, and is therefore an important therapeutic target. Effective management and treatment of dyspnoea is an important challenge for caregivers, and therapeutic options that attempt to reverse its underlying cause have been only partially successful This "review" will attempt to shed light on the physiological mechanisms underlying dyspnoea during exercise and to translate/apply them to a broad clinical spectrum of cardio-respiratory disorders.

Relationship between the sensation of activity limitation and the results of functional assessment in asthma patients

OBJECTIVE

In asthma patients, the assessment of activity limitation is based on questions evaluating how limited the patient feels in their activities. However, the lack of functional data complicates the interpretation of the answers. We aimed to evaluate the intensity of relationships between the patient's perception of activity limitation and the results of several functional tests.

METHODS

Twenty patients complaining of asthma exacerbation were invited to complete three scores (Chronic Respiratory Disease questionnaire, Asthma Control Questionnaire, Hospital Anxiety and Depression scale). They also underwent lung function measurements, a 6-minute walk test and a cardio-pulmonary exercise test. In addition, physical activity was studied by actigraphy. Spearman's rank correlation coefficients between the patient's perception of activity limitation and each of the other parameters were analysed.

RESULTS

Five parameters were significantly correlated with the perception of activity limitation: ACQ question 4, related to dyspnea (rs 0.74, p < 0.001); Emotion domain of the Chronic Respiratory Disease questionnaire (rs -0.57, p = 0.02); HAD anxiety (rs 0.48, p = 0.032); HAD depression (rs 0.46, p = 0.041); ACQ question 6, related to reliever use (rs 0.46, p = 0.046). No parameters from the lung function test, 6MWT, CPET or actigraphy, were significantly correlated with the perception of activity limitation.

CONCLUSIONS

In response to questions about limitation of activity, patients do not specifically answer mentioning physical limitation but rather the psychological burden associated with this constraint.

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.

Mechanical correlates of dyspnea in bronchial asthma

We hypothesized that dyspnea and its descriptors, that is, chest tightness, inspiratory effort, unrewarded inspiration, and expiratory difficulty in asthma reflect different mechanisms of airflow obstruction and their perception varies with the severity of bronchoconstriction. Eighty-three asthmatics were studied before and after inhalation of methacholine doses decreasing the 1-sec forced expiratory volume by ~15% (mild bronchoconstriction) and ~25% (moderate bronchoconstriction). Symptoms were examined as a function of changes in lung mechanics. Dyspnea increased with the severity of obstruction, mostly because of inspiratory effort and chest tightness. At mild bronchoconstriction, multivariate analysis showed that dyspnea was related to the increase in inspiratory resistance at 5 Hz (R 5) (r (2) = 0.10, P = 0.004), chest tightness to the decrease in maximal flow at 40% of control forced vital capacity, and the increase in R 5 at full lung inflation (r (2) = 0.15, P = 0.006), inspiratory effort to the temporal variability in R 5-19 (r (2) = 0.13, P = 0.003), and unrewarded inspiration to the recovery of R 5 after deep breath (r (2) = 0.07, P = 0.01). At moderate bronchoconstriction, multivariate analysis showed that dyspnea and inspiratory effort were related to the increase in temporal variability in inspiratory reactance at 5 Hz (X 5) (r (2) = 0.12, P = 0.04 and r (2) = 0.18, P < 0.001, respectively), and unrewarded inspiration to the decrease in X 5 at maximum lung inflation (r (2) = 0.07, P = 0.04). We conclude that symptom perception is partly explained by indexes of airway narrowing and loss of bronchodilatation with deep breath at low levels of bronchoconstriction, but by markers of ventilation heterogeneity and lung volume recruitment when bronchoconstriction becomes more severe.

Physical training for asthma

BACKGROUND

People with asthma may show less tolerance to exercise due to worsening asthma symptoms during exercise or other reasons such as deconditioning as a consequence of inactivity. Some may restrict activities as per medical advice or family influence and this might result in reduced physical fitness. Physical training programs aim to improve physical fitness, neuromuscular coordination and self confidence. Subjectively, many people with asthma report that they are symptomatically better when fit, but results from trials have varied and have been difficult to compare because of different designs and training protocols. Also, as exercise can induce asthma, the safety of exercise programmes needs to be considered.

OBJECTIVES

To gain a better understanding of the effect of physical training on the respiratory and general health of people with asthma, from randomised trials.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register of trials up to January 2013.

SELECTION CRITERIA

We included randomised trials of people over eight years of age with asthma who were randomised to undertake physical training or not. Physical training had to be undertaken for at least 20 minutes, two times a week, over a minimum period of four weeks.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility for inclusion and undertook risk of bias assessment for the included studies.

MAIN RESULTS

Twenty-one studies (772 participants) were included in this review with two additional 2012 studies identified as 'awaiting classification'. Physical training was well tolerated with no adverse effects reported. None of the studies mentioned worsening of asthma symptoms following physical training. Physical training showed marked improvement in cardiopulmonary fitness as measured by a statistically and clinically significant increase in maximum oxygen uptake (mean difference (MD) 4.92 mL/kg/min; 95% confidence interval (CI) 3.98 to 5.87; P < 0.00001; 8 studies on 267 participants); however, no statistically significant effects were observed for forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), minute ventilation at maximal exercise (VEmax) or peak expiratory flow rate (PEFR). Meta-analysis of four studies detected a statistically significant increase in maximum heart rate, and following a sensitivity analysis and removal of two studies significance was maintained (MD 3.67 bpm; 95% CI 0.90 to 3.44; P = 0.01). Although there were insufficient data to pool results due to diverse reporting tools, there was some evidence to suggest that physical training may have positive effects on health-related quality of life, with four of five studies producing a statistically and clinically significant benefit.

AUTHORS' CONCLUSIONS

This review demonstrated that physical training showed significant improvement in maximum oxygen uptake, though no effects were observed in other measures of pulmonary function. Physical training was well tolerated among people with asthma in the included studies and, as such, people with stable asthma should be encouraged to participate in regular exercise training, without fear of symptom exacerbation. More research is needed to understand the mechanisms by which physical activity impacts asthma management.

Tidal volume inflection and its sensory consequences during exercise in patients with stable asthma

Sixteen patients with stable asthma performed a symptom-limited constant work-rate CWR cycle exercise during which breathing pattern, operating lung volumes, dyspnea intensity and its qualitative descriptors were measured. An inflection in the relation between tidal volume (V(T)) and ventilation (V˙(E)) was observed in each subject. The sense of "work/effort" was the dominant dyspnea descriptor selected up to the V(T)/V˙(E) inflection, whereas after it dyspnea intensity and the selection frequency of "unsatisfied inspiration" rose steeply in 37.5% of subjects in whom inspiratory reserve volume (IRV) had decreased to a critical level of 0.6L at the V(T) inflection point. In contrast, dyspnea increased linearly with exercise time and V˙(E), and "work/effort" was the dominant descriptor selected throughout exercise in 62.5% of subjects in whom the V(T)/V˙(E) inflection occurred at a preserved IRV. The V(T) inflection during exercise in patients with stable asthma marked a mechanical event with important sensory consequences only when it occurred at a critical reduced IRV.

Dyspnea, chest wall hyperinflation, and rib cage distortion in exercising patients with chronic obstructive pulmonary disease

PURPOSE

Whether dyspnea, chest wall dynamic hyperinflation, and abnormalities of rib cage motion are interrelated phenomena has not been systematically evaluated in patients with chronic obstructive pulmonary disease (COPD). Our hypothesis that they are not interrelated was based on the following observations: (i) externally imposed expiratory flow limitation is associated with no rib cage distortion during strenuous incremental exercise, with indexes of hyperinflation not being correlated with dyspnea, and (ii) end-expiratory chest wall volume may either increase or decrease during exercise in patients with COPD, with those who hyperinflate being as breathless as those who do not.

METHODS

Sixteen patients breathed either room air or 50% supplemental O2 at 75% of peak exercise in randomized order. We evaluated the volume of chest wall (V(cw)) and its compartments: the upper rib cage (V(rcp)), lower rib cage (V(rca)), and abdomen (V(ab)) using optoelectronic plethysmography; rib cage distortion was assessed by measuring the phase angle shift between V(rcp) and V(rca).

RESULTS

Ten patients increased end-expiratory V(cw) (V(cw,ee)) on air. In seven hyperinflators and three non-hyperinflators, the lower rib cage paradoxed inward during inspiration with a phase angle of 63.4° ± 30.7° compared with a normal phase angle of 16.1° ± 2.3° recorded in patients without rib cage distortion. Dyspnea (by Borg scale) averaged 8.2 and 9 at the end of exercise on air in patients with and without rib cage distortion, respectively. At iso-time during exercise with oxygen, decreased dyspnea was associated with a decrease in ventilation regardless of whether patients distorted the rib cage, dynamically hyperinflated, or deflated the chest wall.

CONCLUSIONS

Dyspnea, chest wall dynamic hyperinflation, and rib cage distortion are not interrelated phenomena.

Palliation of Dyspnea in pediatrics

Dyspnea is a complex physiologic and psychosocial symptom that is difficult to characterize and measure, but essential to treat, as it has a significant effect on quality of life. Although palliation of dyspnea in the child with chronic illness is an under-researched area, children and their families cannot wait for the research to catch up with their current needs. This article addresses several aspects of dyspnea in pediatrics palliative care, with an eye toward practical suggestions for evaluation and management.

Physical training for asthma

BACKGROUND

People with asthma may show less tolerance to exercise due to worsening asthma symptoms during exercise or other reasons such as deconditioning, as a consequence of inactivity. Some may also restrict activities as per medical advice or family influence and this might result in reduced physical fitness. Physical training programs aim to improve physical fitness, neuromuscular coordination and self confidence. Subjectively, many people with asthma report that they are symptomatically better when fit, but results from trials have varied and have been difficult to compare because of different designs and training protocols. Also, as exercise can induce asthma, the safety of exercise programmes need to be considered.

OBJECTIVES

To gain a better understanding of the effect of physical training on the respiratory and general health of people with asthma, from randomised trials.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register of trials up to April 2011.

SELECTION CRITERIA

We included randomised trials of people over eight years of age with asthma who were randomised to undertake physical training. Physical training had to be undertaken for at least twenty minutes, two times a week, over a minimum period of four weeks.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility for inclusion and the quality of trials.

MAIN RESULTS

Nineteen studies (695 participants) were included in this review. Physical training was well tolerated with no adverse effects reported. None of the studies mentioned worsening of asthma symptoms following physical training. Physical training improved cardiopulmonary fitness as measured by a statistically and clinically significant increase in maximum oxygen uptake (MD 5.57 mL/kg/min; 95% confidence interval (CI) 4.36 to 6.78; six studies on 149 participants) and maximum expiratory ventilation (6.0 L/min, 95% CI 1.57 to 10.43; four studies on 111 participants) with no significant effect on resting lung function (performed in four studies). Although there were insufficient data to pool due to diverse reporting tools, there is some evidence available to suggest that physical training may have positive effects on health-related quality of life, with four of five studies producing a statistically and clinically significant benefit.

AUTHORS' CONCLUSIONS

This review demonstrated that physical training can improve cardiopulmonary fitness and was well tolerated among people with asthma in the included studies. As such, people with stable asthma should be encouraged to partake in regular exercise training, without fear of symptom exacerbation.

An official American Thoracic Society statement: update on the mechanisms, assessment, and management of dyspnea

BACKGROUND

Dyspnea is a common, distressing symptom of cardiopulmonary and neuromuscular diseases. Since the ATS published a consensus statement on dyspnea in 1999, there has been enormous growth in knowledge about the neurophysiology of dyspnea and increasing interest in dyspnea as a patient-reported outcome.

PURPOSE

The purpose of this document is to update the 1999 ATS Consensus Statement on dyspnea.

METHODS

An interdisciplinary committee of experts representing ATS assemblies on Nursing, Clinical Problems, Sleep and Respiratory Neurobiology, Pulmonary Rehabilitation, and Behavioral Science determined the overall scope of this update through group consensus. Focused literature reviews in key topic areas were conducted by committee members with relevant expertise. The final content of this statement was agreed upon by all members.

RESULTS

Progress has been made in clarifying mechanisms underlying several qualitatively and mechanistically distinct breathing sensations. Brain imaging studies have consistently shown dyspnea stimuli to be correlated with activation of cortico-limbic areas involved with interoception and nociception. Endogenous and exogenous opioids may modulate perception of dyspnea. Instruments for measuring dyspnea are often poorly characterized; a framework is proposed for more consistent identification of measurement domains.

CONCLUSIONS

Progress in treatment of dyspnea has not matched progress in elucidating underlying mechanisms. There is a critical need for interdisciplinary translational research to connect dyspnea mechanisms with clinical treatment and to validate dyspnea measures as patient-reported outcomes for clinical trials.

An official American Thoracic Society statement: update on the mechanisms, assessment, and management of dyspnea

BACKGROUND

Dyspnea is a common, distressing symptom of cardiopulmonary and neuromuscular diseases. Since the ATS published a consensus statement on dyspnea in 1999, there has been enormous growth in knowledge about the neurophysiology of dyspnea and increasing interest in dyspnea as a patient-reported outcome.

PURPOSE

The purpose of this document is to update the 1999 ATS Consensus Statement on dyspnea.

METHODS

An interdisciplinary committee of experts representing ATS assemblies on Nursing, Clinical Problems, Sleep and Respiratory Neurobiology, Pulmonary Rehabilitation, and Behavioral Science determined the overall scope of this update through group consensus. Focused literature reviews in key topic areas were conducted by committee members with relevant expertise. The final content of this statement was agreed upon by all members.

RESULTS

Progress has been made in clarifying mechanisms underlying several qualitatively and mechanistically distinct breathing sensations. Brain imaging studies have consistently shown dyspnea stimuli to be correlated with activation of cortico-limbic areas involved with interoception and nociception. Endogenous and exogenous opioids may modulate perception of dyspnea. Instruments for measuring dyspnea are often poorly characterized; a framework is proposed for more consistent identification of measurement domains.

CONCLUSIONS

Progress in treatment of dyspnea has not matched progress in elucidating underlying mechanisms. There is a critical need for interdisciplinary translational research to connect dyspnea mechanisms with clinical treatment and to validate dyspnea measures as patient-reported outcomes for clinical trials.

Musculoskeletal dysfunction and pain in adults with asthma

BACKGROUND

The mechanical alterations related to the overload of respiratory muscles observed in adults with persistent asthma might lead to the development of chronic alterations in posture, musculoskeletal dysfunction and pain; however, these changes remain poorly understood.

OBJECTIVE

This study aimed to assess postural alignment, muscle shortening and chronic pain in adults with persistent asthma.

METHODS

This cross-sectional and controlled study enrolled 30 patients with mild (n = 17) and severe (n = 13) persistent asthma. Fifteen non-asthmatic volunteers were also assessed. Asthma was classified by the Global Initiative for Asthma (GINA) guidelines. Postural alignment and muscle shortening were evaluated by head and shoulder positions, chest wall mobility, and posterior (trunk and lower limb) muscle flexibility. In addition, the measures used were previously tested for their reproducibility. Pain complaints were also assessed.

RESULTS

In comparison with non-asthmatic subjects, patients with mild or severe persistent asthma held their head and shoulders more forward and had lower chest wall expansion, decreased shoulder internal rotation, and decreased thoracic spine flexibility. Chronic lower thoracic, cervical, and shoulder pain was significantly increased in patients with mild or severe asthma compared with non-asthmatic subjects (p < 0.05).

CONCLUSION

Adults with persistent asthma have musculoskeletal dysfunction and chronic pain that is independent of the severity of their disease but that might be related to their age at the onset of disease symptoms.

Frequency of asthma as the cause of dyspnea in pregnancy

OBJECTIVE

To estimate the prevalence of asthma among pregnant women with dyspnea.

METHODS

Pregnant women referred for prenatal care visits who had complaints of dyspnea were included. All pregnant women were evaluated by a respiratory specialist. Spirometry was performed by a single trained physician.

RESULTS

Asthma was diagnosed in 38.8% of participants. Dyspnea was diagnosed as being physiologic in 36.4% of cases, but 24.8% of cases were of probable asthma (spirometric values were within normal range but symptoms and signs were suggestive of asthma). Cough, wheezing, and post-exercise symptoms were significantly more prevalent in asthmatic and probable-asthmatic women than in women without asthma.

CONCLUSION

Dyspnea in pregnancy can be physiologic, but when it is accompanied by other symptoms such as cough or wheezing it is likely to be caused by asthma. Because of the high prevalence of asthma during pregnancy, it seems logical to evaluate dyspnea via physical examination and response to bronchodilators.

Do obstructive and restrictive lung diseases share common underlying mechanisms of breathlessness?

This review tries to answer two main questions: (i) What are the neurophysiological underpinnings of the most commonly selected cluster descriptors which define the qualitative dimension of dyspnea in patients? (ii) How do mechanical constraints affect dyspnea? (iii) Do obstructive and restrictive lung diseases share some common underlying mechanisms? Qualitative dimensions of dyspnea, which allude to increased respiratory work/effort breathing, reflect a harmonious coupling between increased respiratory motor output and lung volume displacement in healthy subjects. Descriptors that allude to unsatisfied inspiration are the dominant qualitative descriptors in patients with a variety of respiratory diseases. It is possible that sensory feedback from a multitude of mechanoreceptors throughout the respiratory system (in the muscle, chest wall, airways and lung parenchyma) collectively convey information to the consciousness that volume/flow or chest wall displacement is inadequate for the prevailing respiratory drive. The data would lend support to the idea that: (i) an altered afferent proprioceptive peripheral feedback signals that ventilatory response is inadequate to the prevailing motor drive, reflecting neuromechanical uncoupling (NMU), (ii) mechanical constraints on volume expansion (dynamic restriction) play a pivotal role in dyspnea causation in patients with a variety of either obstructive or restrictive respiratory disorders, and (iii) all of the physiological adaptations that optimize neuromechanical coupling in obstructive and restrictive disorders are seriously disrupted so that an NMU underpins cluster descriptors of dyspnea which are similar in obstructed and in restricted patients.

Impact of a rehabilitation program on dyspnea intensity and quality in patients with chronic obstructive pulmonary disease

BACKGROUND

It has yet to be determined whether the language of dyspnea responds to pulmonary rehabilitation programs (PRP).

OBJECTIVE

We tested the hypothesis that PRP affect both the intensity and quality of exercise-induced dyspnea in patients with chronic obstructive pulmonary disease (COPD).

METHODS

We studied 49 patients equipped with a portable telemetric spiroergometry device during the 6-min walking test before and 4 weeks after PRP. In a first screening visit, appropriate verbal descriptors of dyspnea were chosen that patients were familiar with during daily living activities. Tidal volume, respiratory frequency, inspiratory capacity, inspiratory reserve volume (IRV) and dyspnea intensity were evaluated by a modified Borg scale every minute during the test.

RESULTS

Qualitative descriptors of dyspnea were defined by three different sets of cluster descriptors (a-c) at the end of the exercise test, before and after PRP: a - work/effort (W/E); b - inspiratory difficulty (ID) and chest tightness (CT), and c - W/E, ID and/or CT. The three language subgroups exhibited similar lung function at baseline, and similar rating of dyspnea and ventilatory changes during exercise. The rehabilitation program shifted the Borg-IRV relationship (less Borg at any given IRV) towards the right without modifying the set of descriptors in most patients.

CONCLUSIONS

Rehabilitation programs allowed patients to tolerate a greater amount of restrictive dynamic ventilatory defect by modifying the intensity, but not necessarily the quality of dyspnea.

Differing reports of asthma symptoms in African Americans and Caucasians

OBJECTIVE

This pilot study explores the reported symptoms in African Americans and Caucasians with asthma.

METHODS

Asthma patients in an inner-city pulmonary clinic were given a brief questionnaire of asthma symptoms and the BORG scale, followed by spirometry.

RESULTS

African Americans were less likely to report nocturnal awakenings (67% vs. 100%; p = 0.037), complain of dyspnea (33% vs. 75%; p = 0.038), or experience chest pain (13% vs. 75%; p = 0.002) than Caucasians.

CONCLUSIONS

This is the first study to demonstrate that there are clinically significant differences in the reporting of asthma symptoms between African Americans and Caucasians.

Adrenergic responsiveness: FEV1 and symptom differences in Whites and African Americans with mild asthma

Decision-making about inhaler use is, in part, determined by the ability of asthmatic patients to compare their symptoms over time and to recall the previous response to the bronchodilator during an episode of asthma. The perception of airway symptoms across varied ethnic and cultural groups are poorly understood. Study purpose was (1) to determine if African Americans and Whites with mild asthma could accurately perceive bronchodilation and (2) to identify the word descriptors they used to describe their breathing. Sixteen African American and 16 White patients (34.5 +/- 9.7 years old, mean+/-SD) with mild atopic asthma (FEV1 > or =70% predicted normal) were given increasing doses of an inhaled bronchodilator (Albuterol) after a methacholine challenge. Albuterol (180 microg) was given, by spacer, at 15 min intervals until the FEV1 increased < 5%. Borg, VAS, and Word Descriptors were collected at baseline and after each dose of Albuterol. Baseline FEV1 after Methacholine provocation was 1.94 +/- .39 L for African Americans and 2.13 +/- .70 L for Whites. After 180 microg and again after 360 microg Albuterol, FEV1 increased to 2.88 +/- 0.48 L for African Americans and 3.37 +/- 0.91 L for Whites. But after 540 microg Albuterol, FEV1 decreased significantly (16%) to 2.42 +/- 1.19 L for African Americans while increasing only slightly to 3.47 +/- 0.95 L for Whites. After this dose, 10/16 African Americans felt "tight at the base of throat" (p < 0.01); 7/16 felt "speech-voice-tight" (p < 0.03) suggesting persistent airway discomfort despite marked improvement in FEV1, Borg and VAS scores compared with baseline values. Word descriptors by African Americans' are a more reliable measure of airway symptoms compared to FEV1, Borg or VAS.

Verbal descriptors of dyspnea in patients with COPD at different intensity levels of dyspnea

BACKGROUND

Verbal descriptors of dyspnea are important in understanding the underlying mechanisms, but little is known about the language of dyspnea in COPD. We examined the language of dyspnea in COPD at different intensity levels of dyspnea.

METHODS

Verbal descriptors of dyspnea were assessed in 64 patients with moderate-to-severe COPD (mean age, 62 years; mean percentage of predicted FEV(1) [FEV(1)%pred], 54.1%) during slight dyspnea at rest (mean Borg score, 1.8), moderate dyspnea during cycle ergometer exercise (mean Borg score, 3.1) and somewhat severe dyspnea during a 6-min walking test before (mean Borg score, 4.2), and after pulmonary rehabilitation (PR) [mean Borg score, 3.5]. Furthermore, the influence of age, gender, baseline lung function (FEV(1)%pred), and PR on the verbal descriptors were studied.

RESULTS

A cluster analysis showed that patients differentiated between five clusters of verbal descriptors of dyspnea: heavy/fast breathing, shallow breathing, obstruction, work/effort, and suffocation. These were related to the intensity level of dyspnea but not to age, gender, baseline lung function, or PR. While shallow breathing was predominant only during slight dyspnea at rest, heavy/fast breathing and to a lesser extent work/effort became more important during moderate and somewhat severe dyspnea during exercise. The clusters heavy/fast breathing and work/effort demonstrated the highest sensitivity in discriminating between different intensity levels of dyspnea and in characterizing the positive effects of PR.

CONCLUSIONS

Verbal descriptors of dyspnea in COPD are related to the intensity level of dyspnea. The clusters heavy/fast breathing and work/effort seem to be particularly sensitive descriptors of dyspnea during exercise in COPD.

Cardiopulmonary responses of asthmatic children to exercise: analysis of systolic and diastolic cardiac function

The aim of this study was to evaluate aerobic exercise capacity, cardiac features and function in a group of asthmatic children who underwent medical treatment. Dynamic exercise testing was done to evaluate aerobic exercise capacity. Echocardiography was performed to identify the effects that asthma-induced pulmonary changes have on respiratory and cardiac function in these patients. The study involved 20 asthmatic children (aged 7-16 years) who were followed at our hospital and 20 age- and sex-matched, healthy control subjects. Sixteen of the asthma cases were moderate and four were severe. All 40 subjects underwent similar series of assessments: multiple modes of echocardiography, treadmill stress testing, pulmonary function testing. The means for forced expiratory volume in 1 sec, forced expiratory flow 25-75%, maximal voluntary ventilation and inspiratory capacity were all significantly higher in the control group. The patient group had significantly lower mean maximal oxygen uptake and mean endurance time than the controls but there were no significant differences between the groups with respect to respiratory exchange ratio or the ventilatory threshold. The control group means for ejection fraction, fractional shortening, left ventricular mass, and left ventricular mass index were significantly higher than the corresponding patient group results. Children with moderate or severe asthma have lower aerobic capacity than healthy children of the same age. The data suggest that most of these children have normal diastolic cardiac function, but exhibit impaired systolic function and have lower LVM than healthy peers of the same age.

Is there a link between the qualitative descriptors and the quantitative perception of dyspnea in asthma?

BACKGROUND

There is no obvious link between qualitative descriptors and overall intensity of dyspnea during bronchoconstriction in patients with asthma.

AIMS

To determine whether qualitative and quantitative perception of methacholine-induced bronchoconstriction independently contribute to characterizing clinically stable asthma.

MATERIAL AND METHODS

We assessed changes in inspiratory capacity, and quantitative (by Borg scale) and qualitative (by a panel of eight dyspnea descriptors) sensations of dyspnea at 20 to 30% fall in FEV(1) during methacholine inhalation in 49 asthmatics. Furthermore, we calculated the level of perception of bronchoconstriction at 20% fall in FEV(1) (PB(20)).

RESULTS

Descriptors selected by patients during methacholine inhalation allowed us to define three language subgroups: (1) chest tightness (subgroup A, n = 21); (2) work/effort (subgroup B, n = 7); and (3) both descriptors (subgroup C, n = 13). Eight of the 49 patients (subgroup D) were not able to make a clear-cut distinction among descriptors. The subgroups exhibited similar function at baseline and during methacholine inhalation. Most importantly, patients selected chest tightness to a greater extent (42.85%), and work/effort (14.3%) and both descriptors (26.5%) to a lesser extent at the lowest level of bronchoconstriction (FEV(1) fall < 10%) as at 20% fall in FEV(1). Thirty-two patients were normoperceivers (PB(20) > or = 1.4 to < 5 arbitrary units [au]), 7 patients were hyperperceivers (PB(20) > or = 5 au), and 10 patients were hypoperceivers (PB(20) < 1.4 au). Language subgroups were equally distributed across the perceiver subgroups.

CONCLUSIONS

In patients with clinically stable asthma, PB(20) and language of dyspnea independently contribute to defining the condition of the disease. However, the possibility that this independence may be due to a beta-error should be taken into account.

Dyspnea assessment and adverse events during sputum induction in COPD

Background

The inhalation of normal or hypertonic saline during sputum induction (SI) may act as an indirect bronchoconstrictive stimulus leading to dyspnea and lung function deterioration. Our aim was to assess dyspnea and adverse events in COPD patients who undergo SI following a safety protocol.

Methods

Sputum was induced by normal and hypertonic (4.5%) saline solution in 65 patients with COPD of varying severity. In order to minimize saline-induced bronchoconstriction a protocol based on the European Respiratory Society sputum induction Task group report was followed. Dyspnea change was scored using the Borg scale and lung function was assessed by spirometry and oximetry.

Results

Borg score changes [median(IQR) 1.5(0–2)] were observed during SI in 40 subjects; 16 patients required temporary discontinuation of the procedure due to dyspnea-general discomfort and 2 did not complete the session due to dyspnea-wheezing. The change in Borg dyspnea score was significantly correlated with oxygen saturation and heart rate changes and with discontinuation of the procedure due to undesired symptoms. 19 subjects presented an hyperresponsive reaction (decline>20% from baseline FEV₁). No significant correlation between Borg changes and FEV₁decline was found. Patients with advanced COPD presented significantly greater Borg and oxygen saturation changes than patients with less severe disease (p = 0.02 and p = 0.001, respectively). Baseline FEV₁, oxygen saturation and 6MWT demonstrated significant diagnostic values in distinguishing subjects who develop an adverse physiologic reaction during the procedure.

Conclusion

COPD patients undergoing SI following a safety protocol do not experience major adverse events. Dyspnea and oxygen desaturation is more likely to occur in patients with disease in advanced stages, leading to short discontinuation or less frequently to termination of the procedure. Baseline FEV₁, oxygen saturation and 6MWT may have a prognostic value for the development of these adverse events and might be useful to be evaluated in advance.