Claudine Peiffer

Measurement of Dynamic Hyperinflation After a 6-Minute Walk Test in Patients With COPD

BACKGROUND Dynamic hyperinflation (DH) develops in patients with COPD during incremental exercise with a cycle ergometer. The aims of this study were to determine whether DH can be evidenced after walking with a handheld spirometer and to determine its functional consequences. METHODS Fifty patients with COPD (39 men; median age, 60 years [interquartile range (IQR), 54 to 69 years]; FEV(1), 45% predicted [IQR, 31 to 67% predicted]) underwent pulmonary function tests and a 6-min walk test (6MWT). Inspiratory capacity (IC) was measured with the patient in the standing position at rest and immediately after the 6MWT with a portable spirometer. Dyspnea was evaluated directly (change in Borg score during 6MWT) and indirectly (Medical Research Council scale). The first 20 patients performed an incremental exercise test with cycle ergometer that allowed for the measurement of IC at peak exercise and repeatedly during the first 3 min of recovery. RESULTS The median change in IC during the 6MWT was -210 mL (IQR, 55 to -440; n = 50), whereas the median change in IC during the exercise test was -295 mL (IQR, -145 to -515; n = 20). Both the IC and IC changes after 6MWT correlated to values after the exercise test. DH decreased rapidly after the end of the exercise test but was nonsignificantly different from the baseline value after 75 s of recovery. The percentage of decrease in IC during the 6MWT correlated with dyspnea (change in Borg score during 6MWT: r(2) = 0.21; p = 0.0006). CONCLUSIONS DH can be measured during a 6MWT with a handheld spirometer to allow for its evaluation in daily practice and its contribution to dyspnea while walking.

Relationships between Specific Airway Resistance and Forced Expiratory Flows in Asthmatic Children

Background The earliest changes associated with airflow obstruction in asthmatic children are a proportionally greater reduction in FEF50% than in FEV1 using spirometry, and an increase in specific airway resistance (sRaw) using body plethysmography. Consequently, we hypothesized that sRaw could be better linked to FEF50% than to FEV1. The first aim was to assess the relationships between forced expiratory flows and sRaw in a large group of asthmatic children in a transversal study. We then performed a longitudinal study in order to determine whether sRaw of preschool children could predict subsequent impairment of forced expiratory flows at school age. Methodology Pulmonary function tests (sRaw and forced expiratory flows) of 2193 asthmatic children were selected for a transversal analysis, while 365 children were retrospectively selected for longitudinal assessment from preschool to school age. Principal Findings The transversal data showed that sRaw is differently related to FEF50% (−1/sRaw) and to FEV1 (near linearly). These results were further explained by a simple one-compartment lung model, which justified the shape of the observed relationships. As hypothesized, sRaw correlated more strongly to FEF50% than to FEV1 (r = −0.64 versus −0.39, respectively; p<0.001). In the longitudinal part of the study, sRaw at preschool age correlated with subsequent FEF50% (% predicted) (−0.31, 95% CI, −0.40 to −0.22), but weakly with subsequent FEV1 (% predicted) (−0.09, 95% CI, −0.20 to 0). Conclusion Specific Raw is more strongly related to FEF50% than to FEV1 and could be used in preschool children to predict subsequent mild airflow limitation.

Use of specific airway resistance to assess bronchodilator response in children

Background and objective:  Changes in specific airway resistance (ΔsRaw) after bronchodilation, as measured by plethysmography and FEV1, are frequently considered to be interchangeable indices of airway obstruction. However, the baseline relationship between these two indices is weak, and the value of ΔsRaw that best predicts FEV1 reversibility in children has yet to be determined. The aim of this study was (i) to establish the sRaw cut‐off value that best distinguishes between positive and negative bronchodilator responses, as measured by FEV1 reversibility; (ii) to determine whether the discrepancy between ΔsRaw and ΔFEV1 might be explained by independent correlations between ΔFEV1 and both ΔsRaw (mainly airway obstruction) and ΔFVC (airway closure); and (iii) to assess the effect of height and age on the relationship between ΔsRaw and ΔFEV1.

Lumen areas and homothety factor influence airway resistance in COPD

The remodelling process of COPD may affect both airway calibre and the homothety factor, which is a constant parameter describing the reduction of airway lumen (h(d): diameter of child/parent bronchus) that might be critical because its reduction would induce a frank increase in airway resistance. Airway dimensions were obtained from CT scan images of smokers with (n=22) and without COPD (n=9), and airway resistance from plethysmography. Inspiratory airway resistance correlated to lumen area of the sixth bronchial generation of right lung, while peak expiratory flow correlated to the area of the third right generation (p=0.0009, R=0.57). A significant relationship was observed between h(d) and resistance (p=0.036; R(2)=0.14). A modelling approach of central airways (5 generations) further described the latter relationship. In conclusion, a constant homothety factor can be described by CT scan analysis, which partially explains inspiratory resistance, as predicted by theoretical arguments. Airway resistance is related to lumen areas of less proximal airways than commonly admitted.

Gas trapping is associated with severe exacerbation in asthmatic children.

BACKGROUND Gas trapping suggesting small airway disease is observed in adult asthmatic suffering from severe asthma. The aim of the study was to assess whether gas trapping could be evidenced in asthmatic children with/without severe exacerbation and with/without symptoms during the past three months. METHODS AND PATIENTS Forced expiratory flows (FEV(1), FVC, MEF(25-75%), MEF(50%)), plethysmographic lung volumes (TLC, FRC, RV) before and after bronchodilation (BD) were recorded in asthmatic children with documented airflow reversibility. Three groups were defined according to the presence during the last three months of 1) severe exacerbation (oral steroid: 3 consecutive days) 2) asthma symptoms without severe exacerbation and 3) without any symptom (GINA guidelines). RESULTS 180 children (median 11.3 years, range 6.3-17.6, 57 girls) were included, 24 (13%) had at least one severe exacerbation, 58 (33%) had respiratory symptoms without severe exacerbation and 98 (54%) had no symptom during the past 3 months. Forced expiratory flows did not significantly differ in these three groups, while RV/TLC was significantly higher in the first group before and even after bronchodilation: before BD, 0.27 +/- 0.07, 0.24 +/- 0.05 and 0.23 +/- 0.05, respectively (p = 0.016) and after BD, 0.25 +/- 0.07, 0.21 +/- 0.05, 0.21 +/- 0.05, respectively (p = 0.003). CONCLUSION In asthmatic children, gas trapping is associated with occurrence of a severe exacerbation during the last three months, suggesting a small airway disease that is not evidenced by forced expiratory flows.

What Does a Single Exhaled Nitric Oxide Measurement Tell us in Asthmatic Children

Background. Due to the multiple factors affecting exhaled nitric oxide (NO) value, physicians are often puzzled by the result of a single measurement in asthmatic patients. Objective. The aim of this prospective transversal study was to evaluate the relative contributions to exhaled NO fraction (FENO) of the commonly considered major NO determinants, i.e., recent symptoms (upper and lower respiratory tract), atopy (prick skin tests and degree of allergic exposure), and treatment (dose of inhaled corticosteroid [ICS]) to know what information gives a single measure. Methods. FENO at 50 mL/s expiratory flow was measured in 199 asthmatic children (141 boys, age: 11.2 years ± 2.5 years). The allergic risk due to pollen exposure (ARPE index) was independently evaluated by the “Réseau National de Surveillance Aérobiologique.” Results. A multivariate analysis of FENO as dependent variable showed that explanatory variables explained 23% of total FENO variance (symptoms > atopy > ICS). In the children without recent symptoms (n = 118), a FENO > 23 ppb predicted atopy (sensitivity 47%, specificity 85%, p = 0.0006). Multiple regression only showed a trend to significance between FENO and the dose of ICS (p = 0.057, r = − 0.19). Incidentally, despite similar dose of ICS, children under fluticasone (mean ± SD, 259 ± 149 μg/day) had lower FENO than those under budesonide (299 ± 195 μg/day) (median [interquartile], 21 ppb [14–42], n = 55 versus 35 ppb [19–47], n = 104; p = 0.007), which may be due to a higher potency of fluticasone. A relationship between FENO and ARPE index was significant in children with exclusive seasonal sensitisation (n = 31, r = 0.48, p = 0.008). Conclusion. Common exhaled NO determinants weakly explain a single value of FENO, which only can confidently predict atopy.

Lung Function Impairment Evidenced by Sequential Specific Airway Resistance in Childhood Persistent Asthma: A Longitudinal Study

Background. Specific airway resistance (sRaw) is virtually independent of lung growth, height, and gender, thus facilitating longitudinal follow-up. Objective. To assess whether a specific phenotype of asthmatic children with a decline in lung function can be evidenced using sRaw. Methods. The authors hypothesized that sequential sRaw measurements over a long period would detect subtle trends. Clinical and functional data of children with persistent asthma under inhaled corticosteroids, evaluated at least three times per year for at least 4 years, were retrieved from a database. Results. One hundred fourteen children (30 girls) were followed for (median [interquartile range]) 6.9 years [5.6–7.9]. Data from 1699 measurements of sRaw (median 14/child) allowed the calculation of individual slopes of sRaw plotted against time demonstrating stable values in the group as a whole between 4 and 18 years. A positive correlation between individual slopes and the degree of intraindividual variation of sRaw was observed (R2 = .16; p < .0001). Children with more than one positive skin test showed larger intrasubject variation of sRaw (p = .011). In 19/114 children (17%), a significant increase in sRaw of 12.3% per year (median) was observed. As compared to children without, those with a significant increase in sRaw were boys (p < .0001), had a lower initial (p = .008) and a higher final resistance (p = .025) but did not differ in terms of inhaled corticosteroid dose. Conclusion. This retrospective study identifies a specific phenotype of asthmatic children that develops an impairment of lung function, confirming the results of a post hoc analysis of the Childhood Asthma Management Program study.

Can Bronchodilator Response Predict Bronchial Response to Methacholine in Preschool Coughers

The aim of the present study was to determine the relationship between bronchodilator response, assessed by interrupter resistance (Rint), and bronchial reactivity in preschool children with chronic cough. Thirty‐eight children coughers (median age 5.0 years, range 2.8–6.4) were tested. Bronchodilator response was recorded within 4 months before methacholine challenge. Response to the latter was assessed using transcutaneous partial pressure of oxygen and Rint. Children were considered responders if a 20% fall in transcutaneous partial pressure of oxygen occurred during the bronchial challenge. Bronchodilator response was not different between responders (n = 24) and nonresponders (n = 14) [median (range) −0.11 (−0.44–0.09) vs. −0.08 (−0.21–0.10) kPa L−1 sec; respectively]. However, none of the nonresponders had a bronchodilator response larger than −0.21 kPa L−1 sec, this cutoff had a 100% positive and a 44% negative predictive value to predict a positive methacholine challenge. The relationship between bronchodilator response and bronchial methacholine responsiveness reached the limit of significance (P = 0.048). Furthermore, the magnitude of the bronchodilator response was correlated to the level of methacholine‐induced level of bronchoconstriction (P = 0.01), and to the postchallenge bronchodilation (P = 0.04), all values expressed as % predicted. Moreover, the postbronchodilator Rint value obtained with preceding methacholine challenge was lower than the postbronchodilator value without preceding methacholine challenge in 71.4% (10/14) of the nonresponders and in only 33.3% (8/24) of the responders. Conclusions in preschool coughers bronchodilator response, assessed by the interrupter technique, was correlated to the bronchial responsiveness to methacholine. Non responders had a bronchodilator response not larger than −0.21 kPa L−1 sec. Pediatr Pulmonol. 2008; 43:815–821.

Breathlessness despite optimal pathophysiological treatment: on the relevance of being chronic

In the May 2017 issue of the European Respiratory Journal (ERJ), Johnson et al. [1] proposed the term “chronic breathlessness syndrome” to describe the clinical situation in which “breathlessness that persists despite optimal treatment of the underlying pathophysiology and results in disability for the patient”. The term “disability” in this definition corresponds to “physical limitations and/or a variety of adverse psychosocial, spiritual or other consequences”, which very closely matches the World Health Organization definition of the word [2]. The relationship between breathlessness and disability was well captured in the foreword of a document published in 2013 by the Forum of International Respiratory Societies [3], which begins: “When we are healthy, we take our breathing for granted […]. But when our lung health is impaired, nothing else but our breathing really matters”. This has become the “catch phrase” of the French lung health foundation (“Fondation du Souffle”, www.lesouffle.org). The explicit definition of “chronic breathlessness” as proposed by Johnson et al. [1] differs very little from the implicit definition of “refractory breathlessness”, the term previously used in many studies, and which was proposed as a distinct entity by some of the authors of a previously published ERJ article [4]. Johnson et al. [1] submit that defining and naming this new syndrome will improve the visibility of a distressing and debilitating condition that is too often overlooked and neglected [5]. They postulate that this enhanced visibility will result in improved care and organisation of care, stronger research [6], and greater empowerment for patients and their caregivers. The Editorial by Başoğlu [7] published in the May 2017 issue of the ERJ throws new light on this notion of empowerment. Making a daring but fascinating parallel between untreated dyspnoea and torture, Başoğlu [7] reminds us how and why addressing dyspnoea in general (and probably “chronic breathlessness” in particular) is a fundamental issue not only from the point of view of medicine per se, but also from the point of view of human rights (on this, see also [8]). He also makes a very convincing case for the importance of empowerment in the management of dyspnoea. Still in the same issue of the ERJ, Calverley [9] comments on the new syndrome and, like us, concurs with Johnson et al. [1] about the relevance of making breathlessness a foremost concern of every clinician. Despite maximal pathophysiological treatment, persistent dyspnoea is a distinct entity, be it chronic or acute http://ow.ly/7cR530equaI

Pathophysiology of dyspnoea in acute pulmonary embolism: A cross-sectional evaluation.

Dyspnoea in pulmonary embolism (PE) remains poorly characterized. Little is known about how to measure intensity or about the underlying mechanisms that may be related to ventilatory abnormalities, alveolar dead space ventilation or modulating factors such as psychological modulate. We hypothesized that dyspnoea would mainly be associated with pulmonary vascular obstruction and its pathophysiological consequences, while the sensory‐affective domain of dyspnoea would be influenced by other factors.