Publications (61)291.52 Total impact
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Article: CROSS-SECTIONAL ASSESSMENT OF THE ROLES OF COMORBIDITIES IN RESTING AND ACTIVITY-RELATED DYSPNOEA IN SEVERELY OBESE WOMEN.
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ABSTRACT: Objectives. Obesity has been associated with a lesser degree of asthma control that may be biased by other comorbidities. The objectives of this cross-sectional study were to describe resting and activity-related dyspnoea complaints according to the presence of obesity-related comorbidities (asymptomatic airway hyperresponsiveness, asthma, gastroesophageal reflux disease and sleep disordered breathing). We hypothesised that obese women can exhibit both resting and activity-related dyspnoea, independently of the presence of asthma. Methods. Severely obese (BMI >35 kg.m(-2)) women prospectively underwent description of resting and activity-related dyspnoea (verbal descriptors, Medical Research Council scale), pulmonary function testing (spirometry, absolute lung volumes, methacholine challenge test), oesogastro-duodenal fibroscopy and overnight polygraphy. Thirty healthy lean women without airway hyperresponsiveness were enrolled. Results. Resting dyspnoea complaints were significantly more prevalent in obesity (prevalence 41%) than in healthy lean women (prevalence 3%). Chest tightness and the need for deep inspirations were independently associated with both asthma and gastroesophageal reflux disease while wheezing and cough were related to the association of asthma only and gastroesophageal reflux disease in while wheezing and cough were related to asthma only in obese women. Activity-related dyspnoea was very prevalent (MRC score >1, 75%), associated with obesity, with the exception of wheezing on exertion due to asthma. Asymptomatic airway hyperresponsiveness and sleep disordered breathing did not affect dyspnoeic complaints. Conclusions. In severely obese women referred for bariatric surgery, resting dyspnoea complaints are observed in association with asthma or gastroesophageal reflux disease, while activity-related dyspnoea was mainly related to obesity only. Consequently, asthma does not explain all respiratory complaints of obese women.Journal of Asthma 04/2013; · 1.52 Impact Factor -
Article: Risk factors for airway hyperresponsiveness in severely obese women.
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ABSTRACT: Obesity affects airway diameter and tidal ventilation pattern, which could perturb smooth muscle function. The objective was to assess the pathophysiology of airway hyperresponsiveness in obesity while controlling for gastro-oesophageal reflux disease. Obese women (n=118, mean±SD BMI 46.1±6.8kg/m(-2)) underwent pulmonary function testing (including tidal ventilation monitoring and methacholine challenge) and oesogastro-duodenal fibroscopy. Fifty-seven women (48%, 95% CI: 39% to 57%) exhibited hyperresponsiveness (dose-response slope ≥ 2.39% decrease/μmol) that was independently and positively correlated with predicted % FRC, Raw(0.5) and negatively correlated with sigh frequency during tidal ventilation. Obese women had an increased breathing frequency but a similar sigh frequency than healthy lean women (n=30). Twenty-two obese women (19%, 95% CI: 12% to 26%) were classified as asthmatics (hyperresponsiveness and suggestive symptoms) without confounding effect of gastro-oesophageal reflux disease. In conclusion, in women referred for bariatric surgery, unloading of bronchial smooth muscle (reduced airway caliber and sigh frequency) is associated with hyperresponsiveness.Respiratory Physiology & Neurobiology 01/2013; · 2.24 Impact Factor -
Article: BMI as a comorbidity factor in childhood asthma.
Expert Review of Respiratory Medicine 12/2012; 6(6):569-71. -
Article: Activity-related dyspnea is not modified by psychological status in people with COPD, interstitial lung disease or obesity.
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ABSTRACT: Sensory (physiological) and affective (psychological) dimensions of dyspnea have been described but the usefulness of measuring psychological status in addition to ventilatory capacity (spirometry, lung volumes) in the assessment of exertional dyspnea remains controversial. We hypothesized that activity-related dyspnea would not be modified by psychological status. Principal component analysis (PCA) was used to reduce the number of parameters (psychological or functional) to fewer independent dimensions in 328 patients with altered ventilatory capacity: severe obesity (BMI ≥ 35, n = 122), COPD (n = 128) or interstitial lung disease (n = 78). PCA demonstrated that psychological status (Hospital Anxiety-Depression, Fatigue Impact scales) and dyspnea (Medical Research Council [MRC] scale) were independent dimensions. Ventilatory capacity was described by three main dimensions by PCA related to airways, volumes, and their combination (specific airway resistance, FEV(1)/FVC), which were weakly correlated with dyspnea. In conclusion, in patients with COPD, interstitial lung disease or severe obesity, psychological status does not modify activity-related dyspnea rating as evaluated by the MRC scale.Respiratory Physiology & Neurobiology 02/2012; 182(1):18-25. · 2.24 Impact Factor -
Article: Baseline and post-bronchodilator interrupter resistance and spirometry in asthmatic children.
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ABSTRACT: In children unable to perform reliable spirometry, the interrupter resistance (R(int) ) technique for assessing respiratory resistance is easy to perform. However, few data are available on the possibility to use R(int) as a surrogate for spirometry. We aimed at comparing R(int) and spirometry at baseline and after bronchodilator administration in a large population of asthmatic children. We collected retrospectively R(int) and spirometry results measured in 695 children [median age 7.8 (range 4.8-13.9) years] referred to our lab for routine assessment of asthma disease. Correlations between R(int) and spirometry were studied using data expressed as z-scores. Receiver operator characteristic curves for the baseline R(int) value (z-score) and the bronchodilator effect (percentage predicted value and z-score) were generated to assess diagnostic performance. At baseline, the relationship between raw values of R(int) and FEV(1) was not linear. Despite a highly significant inverse correlation between R(int) and all of the spirometry indices (FEV(1) , FVC, FEV(1) /FVC, FEF(25-75%) ; P < 0.0001), R(int) could detect baseline obstruction (FEV(1) z-score ≤ -2) with only 42% sensitivity and 95% specificity. Post-bronchodilator changes in R(int) and FEV(1) were inversely correlated (rhô = -0.50, P < 0.0001), and R(int) (≥35% predicted value decrease) detected FEV(1) reversibility (>12% baseline increase) with 70% sensitivity and 69% specificity (AUC = 0.79). R(int) measurements fitted a one-compartment model that explained the relationship between flows and airway resistance. We found that R(int) had poor sensitivity to detect baseline obstruction, but fairly good sensitivity and specificity to detect reversibility. However, in order to implement asthma guidelines for children unable to produce reliable spirometry, bronchodilator response measured by R(int) should be systematically studied and further assessed in conjunction with clinical outcomes. Pediatr Pulmonol. 2012. 47:987-993. © 2012 Wiley Periodicals, Inc.Pediatric Pulmonology 02/2012; 47(10):987-93. · 2.53 Impact Factor -
Article: Diffusing capacity for carbon monoxide is linked to ventilatory demand in patients with chronic obstructive pulmonary disease.
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ABSTRACT: Dyspnea is deemed to result from an imbalance between ventilatory demand and capacity. The single-breath diffusing capacity for carbon monoxide (DLCO) is often the best correlate to dyspnea in COPD. We hypothesized that DLCO contributes to the assessment of ventilatory demand, which is linked to physiological dead space /tidal volume (V(D)/V(T)) ratio. An additional objective was to assess the validity of non-invasive measurement of transcutaneous P(CO2) allowing the calculation of this ratio. Forty-two subjects (median [range] age: 66 [43-80] years; 12 females) suffering mainly from moderate-to-severe COPD (GOLD stage 2 or 3: n = 36) underwent pulmonary function and incremental exercise tests while taking their regular COPD treatment. DLCO% predicted correlated with both resting and peak physiological V(D)/V(T) ratios (r = -0.55, p = 0.0015 and r = -0.40, p = 0.032; respectively). The peak physiological V(D)/V(T) ratio contributed to increase ventilation (increased ventilatory demand), to increase dynamic hyperinflation and to impair oxygenation on exercise. Indirect (MRC score) and direct (peak Borg score/% predicted VO(2)) exertional dyspnea assessments were correlated and demonstrated significant relationships with DLCO% predicted and physiological V(D)/V(T) at peak exercise, respectively. The non-invasive measurement of transcutaneous P(CO2) both at rest and on exercise was validated by Bland-Altman analyses. In conclusion, DLCO constitutes and indirect assessment of ventilatory demand, which is linked to exertional dyspnea in COPD patients. The assessment of this demand can also be non invasively obtained on exercise using transcutaneous PCO(2) measurement.COPD Journal of Chronic Obstructive Pulmonary Disease 02/2012; 9(1):16-21. · 1.79 Impact Factor -
Article: Relationships between respiratory and airway resistances and activity-related dyspnea in patients with chronic obstructive pulmonary disease.
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ABSTRACT: The aims of the study were: (1) to compare numerical parameters of specific airway resistance (total, sRaw(tot), effective, sRaw(eff) and at 0.5 L · s(-1), sRaw(0.5)) and indices obtained from the forced oscillation technique (FOT: resistance extrapolated at 0 Hz [Rrs(0 Hz)], mean resistance [Rrs(mean)], and resistance/frequency slope [Rrs(slope)]) and (2) to assess their relationships with dyspnea in chronic obstructive pulmonary disease (COPD). A specific statistical approach, principal component analysis that also allows graphic representation of all correlations between functional parameters was used. A total of 108 patients (mean ± SD age: 65 ± 9 years, 31 women; GOLD stages: I, 14; II, 47; III, 39 and IV, 8) underwent spirometry, body plethysmography, FOT, and Medical Research Council (MRC) scale assessments. Principal component analysis determined that the functional parameters were described by three independent dimensions (airway caliber, lung volumes and their combination, specific resistance) and that resistance parameters of the two techniques were not equivalent, obviously. Correlative analyses further showed that Raw(tot) and Raw(eff) (and their specific resistances) can be considered as equivalent and correlated with indices that are considered to explore peripheral airways (residual volume (RV), RV/ total lung capacity (TLC), Rrs(slope)), while Rrs(mean) and Raw(0.5) explored more central airways. Only specific resistances taking into account the specific resistance loop area (sRaw(tot) and sRaw(eff)) and Rrs(slope) were statistically linked to dyspnea. Parameters obtained from both body plethysmography and FOT can explore peripheral airways, and some of these parameters (sRaw(tot), sRaw(eff,) and Rrs(slope)) are linked to activity-related dyspnea in moderate to severe COPD patients.International Journal of COPD 01/2012; 7:165-71. -
Article: Airway responsiveness measured by forced oscillation technique in severely obese patients, before and after bariatric surgery.
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ABSTRACT: The influence of obesity on airway responsiveness remains controversial. This study was designed to investigate airway responsiveness, airway inflammation, and the influence of sleep apnea syndrome (SAS), in severely obese subjects, before and after bariatric surgery. A total of 120 non-asthmatic obese patients were referred consecutively for pre-bariatric surgery evaluation. Lung function, airway responsiveness to methacholine, exhaled nitric oxide measurement, and sleep studies were performed. Airway hyperresponsiveness (AHR) was defined as a 50% or greater increase in respiratory resistance measured using the forced oscillation technique in response to a methacholine dose ≤ 2000 μg. Forced expiratory volume in 1 second (FEV₁) was measured after the last methacholine dose. Airway responsiveness was reevaluated after weight loss in patients with a pre-surgery AHR. AHR was found in 16 patients. The percent FEV₁ decrease or percent respiratory resistance increase in response to methacholine was related to baseline expiratory airflow (forced expiratory flow at 50%) (r = 0.26, p < .006 and r = 0.315, p = .0005, respectively) but not to body mass index (BMI) or exhaled nitric oxide. Both airway responsiveness parameters were significantly related to forced expiratory flow at 25-75%/forced vital capacity, a measure of airway size relative to lung size (r = 0.27, p < .005 and r = 0.25, p < .007, respectively). Sleep apnea was not significantly associated with AHR or airway inflammation. About 11 patients with AHR were reevaluated 18 months to 2 years after surgery, with no change in AHR associated with weight loss. Airway responsiveness is not related to BMI or to SAS. AHR in severely obese patients might be related to distal airway obstruction or low relative airway size.Journal of Asthma 09/2011; 48(8):818-23. · 1.52 Impact Factor -
Article: Pathophysiology of airway hyperresponsiveness in patients with nasal polyposis.
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ABSTRACT: It has been hypothesized that airway hyperresponsiveness (AHR) is characterized by sensitivity (strength of stimulus) and reactivity (responsiveness to stimulus); the latter could be the intrinsic characteristic of AHR. The underlying mechanisms leading to AHR could be 1) airway inflammation, 2) reduction of forces opposing bronchoconstriction, and 3) structural airway changes/geometric factors. Our main objective was to assess the relationships between reactivity in patients with nasal polyposis and these three mechanisms using measurements of 1) bronchial and bronchiolar/alveolar NO, 2) bronchomotor response to deep inspiration, and 3) forced expiratory flows and an index of airway to lung size, i.e. FEF(25-75%)/FVC. Patients underwent spirometry, multiple flow measurement of exhaled NO (corrected for axial diffusion), assessment of bronchomotor response to deep inspiration by forced oscillation technique and methacholine challenge allowing the calculation of reactivity (slope of the dose-response curve) and sensitivity (PD(10)). One hundred and thirty-two patients were prospectively enrolled of whom 71 exhibited AHR. Airway reactivity was correlated with alveolar NO concentration (rho = 0.35; p = 0.017), with airflow limitation (FEF(25-75%): rho = -0.40; p = 0.003) and with an index of airway size to lung size (FEF(25-75%)/FVC: rho = -0.38; p = 0.005), of which only alveolar NO remained the only independent factor in a stepwise multiple regression analysis (variance 25%). Airway sensitivity was not correlated with any pulmonary function or exhaled NO parameter. In patients with nasal polyposis, alveolar NO is associated with airway reactivity, suggesting that bronchiolar/alveolar lung inflammation may constitute one intrinsic characteristic of increased responsiveness.Respiratory medicine 08/2011; 106(1):68-74. · 2.33 Impact Factor -
Article: Peripheral airway/alveolar nitric oxide concentration in asthma.
Thorax 07/2011; 66(7):632-3; author reply 633. · 6.84 Impact Factor -
Article: Exhaled nitric oxide and clinical phenotypes of childhood asthma.
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ABSTRACT: Whether exhaled NO helps to identify a specific phenotype of asthmatic patients remains debated. Our aims were to evaluate whether exhaled NO (FENO(0.05)) is independently associated (1) with underlying pathophysiological characteristics of asthma such as airway tone (bronchodilator response) and airway inflammation (inhaled corticosteroid [ICS]-dependant inflammation), and (2) with clinical phenotypes of asthma.We performed multivariate (exhaled NO as dependent variable) and k-means cluster analyses in a population of 169 asthmatic children (age ± SD: 10.5 ± 2.6 years) recruited in a monocenter cohort that was characterized in a cross-sectional design using 28 parameters describing potentially different asthma domains: atopy, environment (tobacco), control, exacerbations, treatment (inhaled corticosteroid and long-acting bronchodilator agonist), and lung function (airway architecture and tone). Two subject-related characteristics (height and atopy) and two disease-related characteristics (bronchodilator response and ICS dose > 200 μg/d) explained 36% of exhaled NO variance. Nine domains were isolated using principal component analysis. Four clusters were further identified: cluster 1 (47%): boys, unexposed to tobacco, with well-controlled asthma; cluster 2 (26%): girls, unexposed to tobacco, with well-controlled asthma; cluster 3 (6%): girls or boys, unexposed to tobacco, with uncontrolled asthma associated with increased airway tone, and cluster 4 (21%): girls or boys, exposed to parental smoking, with small airway to lung size ratio and uncontrolled asthma. FENO(0.05) was not different in these four clusters.In conclusion, FENO(0.05) is independently linked to two pathophysiological characteristics of asthma (ICS-dependant inflammation and bronchomotor tone) but does not help to identify a clinically relevant phenotype of asthmatic children.Respiratory research 05/2011; 12:65. · 3.36 Impact Factor -
Article: Tobacco-associated pulmonary vascular dysfunction in smokers: role of the ET-1 pathway.
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ABSTRACT: Pulmonary vascular remodeling and dysfunction associated to tobacco smoking might pave the way for the subsequent development of pulmonary hypertension. Its prognosis is dreadful and its underlying mechanisms are so far largely unknown in humans. To assess the potential role of endothelin-1 and its receptors in smokers' pulmonary artery vasoactive properties. Endothelium-dependent vasodilation to ACh was assessed in pulmonary vascular rings from 34 smokers and compared with that of 10 nonsmokers. The effects of ET-A (BQ 123) or ET-B (BQ 788) blockers and that of an ET-B activator (sarafotoxin) were evaluated. Endothelin-1 was quantitated by ELISA. Expression of its receptors was quantitated by Western blotting. Smokers exhibited an impaired pulmonary endothelium-dependent vasodilation compared with nonsmokers (P < 0.01). In the former group, 8 of 34 subjects exhibited a marked endothelial dysfunction (ED(+)) whereas 26 (ED(-)) (P < 10(-4)) displayed a vasorelaxation to ACh that was comparable to that of nonsmokers. In ED(+) subjects, ET-A was overexpressed (P < 0.05) and inversely correlated (P < 10(-2)) with the response to ACh. Sarafotoxin significantly improved vasodilation in all subjects (P < 10(-2)). In conclusion, tobacco smoking is associated to an impaired pulmonary vasorelaxation at least partly mediated by an ET-1/ET-A-dependent dysfunction.AJP Lung Cellular and Molecular Physiology 03/2011; 300(6):L831-9. · 3.66 Impact Factor -
Article: Use of specific airway resistance to assess bronchodilator response in children.
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ABSTRACT: Changes in specific airway resistance (ΔsRaw) after bronchodilation, as measured by plethysmography and FEV(1) , 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 FEV(1) 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 FEV(1) reversibility; (ii) to determine whether the discrepancy between ΔsRaw and ΔFEV(1) might be explained by independent correlations between ΔFEV(1) 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 ΔFEV(1) . A retrospective study was performed in 481 children (median age 10.5years, range 6.1-17.6) with actual or suspected asthma, for whom sRaw and spirometry data were obtained at baseline and after administration of a bronchodilator. The sRaw cut-off value that best predicted FEV(1) reversibility was a 42% decrease from baseline (P=0.0001, area under the curve 0.70, sensitivity 55%, specificity 77%) and was independent of height and age. Changes in FEV(1) were significantly but independently related to ΔsRaw and ΔFVC (index of air trapping) (r=0.40, P<0.0001 and r=0.39, P<0.0001, respectively). A 42% decrease in sRaw predicted FEV(1) reversibility reasonably well, whereas a smaller decrease in sRaw failed to detect approximately one out of two positive responses detected by FEV(1) , with no influence of height or age.Respirology 03/2011; 16(4):666-71. · 2.42 Impact Factor -
Article: Influenza-like illness responsible for severe exacerbations in asthmatic children during H1N1 pandemic: a survey before vaccination.
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ABSTRACT: Asthma seems to be the more prevalent underlying condition in patients hospitalized for H1N1-related flu. A prospective survey was conducted during the early phase of H1N1 pandemic in France in asthmatic children before vaccination to assess whether severe exacerbations in childhood asthma are associated with influenza-like illness (ILI, the definition of H1N1-related flu in a pandemic). Eight pediatricians in primary care distributed in three localities (Paris, south suburb, and west suburb) conducted the survey (4 weeks/locality from week 36 to 47). At each visit, the pediatrician filled a questionnaire entering the information regarding asthma treatment, severe exacerbation (at least 3 days' use of systemic corticosteroids), and ILI (temperature ≥37.8°C, cough, and/or sore throat, in the absence of a known cause other than influenza) during the past 3 weeks. The survey included 1155 asthmatic children (mean age [SD]: 7.5 years [4.1]); almost all visits were scheduled (99%). A severe exacerbation was recorded in 121 children [10.5%; 95% confidence interval (CI): 8.7-12.2%], which was concomitant with ILI in 20 children (16.5%; 95% CI: 9.9-23.2%), whereas 1034 children did not exhibit any exacerbation. In these latter children, 40 ILI were observed (3.9%; 95% CI: 2.7-5.0%), which constituted a significantly lesser percentage as compared with children with both exacerbation and ILI (p < .0001). This result remained significant in each locality. Overall, 60/1155 (5.2%; 95% CI: 3.9-6.5%) asthmatic children had an ILI. Our survey shows that severe exacerbation and ILI are strongly associated during the H1N1 pandemic in asthmatic children.Journal of Asthma 02/2011; 48(3):224-7. · 1.52 Impact Factor -
Article: Too rapid increase and too much breathlessness are distinct indices of exertional dyspnea in COPD.
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ABSTRACT: To assess whether different indices of dyspnea can be obtained from cardiopulmonary exercise test and whether these indices correlate with distinct physiological parameters in COPD. Forty-two COPD patients (12 females, median [IQ] age 66 [56-70] years; FEV(1)% predicted: 51 [38-65]) underwent pulmonary function and incremental exercise tests. A power law function described the oxygen consumption (V(O₂)-Dyspnea relationship from which two indices correlated with MRC score: dyspnea score measured at 50% of predicted V(O₂) (too much breathless for that effort) and tangent measured at 50% of peak dyspnea (too rapid increase in dyspnea at this time point). The former independently correlated with ventilation on exercise, while the latter independently correlated with baseline hyperinflation. An upward shift of both (iso)-V(O₂) and -ventilation was evidenced in patients with higher levels of dyspnea (MRC score ≥ 3) and their tangents were significantly different. In conclusion, baseline hyperinflation is associated with the perception of a too rapid increase in dyspnea on exercise in COPD.Respiratory Physiology & Neurobiology 01/2011; 176(1-2):32-8. · 2.24 Impact Factor -
Article: Association of ex vivo vascular and bronchial dysfunctions in smokers.
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ABSTRACT: It has recently been shown that systemic endothelial dysfunction is associated with airflow limitation in COPD. We conducted this ex vivo study to assess whether endothelial dysfunction of pulmonary arteries of former smokers was associated with modifications of airway functions. Pharmacological experiments were conducted on arterial and bronchial rings obtained from lung specimen of 20 patients: 13 smokers without COPD and 7 smokers with mild to moderate COPD (GOLD class I or II). The impairment of acetylcholine-mediated vasodilation (constriction) of preconstricted arterial rings defined endothelial dysfunction. Resting tone (initial and after a contraction test) and cGMP-mediated dilation of bronchial rings in response to zaprinast were evaluated. Initial airway resting tone was correlated with airflow limitation (FEV(1) % predicted: Rho = -0.49; p = 0.032). The acetylcholine response of arterial rings was correlated with zaprinast-induced bronchodilation (Rho = 0.54, p = 0.019). Patients with endothelial dysfunction (n = 5), as compared with those displaying no dysfunction (n = 15), were characterized by an increased resting tone (after contraction test), an impaired response to zaprinast but a similar degree of airflow limitation (FEV(1)). Endothelial dysfunction of pulmonary arteries is associated with increased resting tone and impaired cGMP-mediated dilation of airways in former smokers, suggesting common underlying mechanisms of pulmonary arterial and bronchial dysfunctions.Pulmonary Pharmacology & Therapeutics 12/2010; 24(2):227-31. · 2.80 Impact Factor -
Article: Influence of age on the risk of severe exacerbation and asthma control in childhood.
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ABSTRACT: Asthma is a heterogeneous disease but it is a common observation that children tend to "grow out of their asthma." The aim was to specifically assess the influence of age on the occurrence of a severe exacerbation (at least 3 days use of systemic corticosteroid--international 2009 definition) and of the achievement of control (GINA guidelines) in children treated for asthma. Our study was controlled for amount of therapy and for season. Children under inhaled corticosteroid (ICS) were enrolled over two 2-month periods (autumn, spring). Duration of oral steroid treatment and of symptoms, dose of ICS and long-acting beta-agonist were recorded for the past 3 months. Three hundred and fifty-nine children (110 girls) were included (48 [<2 years], 116 [2-6 years], 107 [6-10 years], 88 [>10 years]) during autumn (n = 175) and spring (n = 184), all treated by ICS (mean daily dose ± SD = 378 ± 250 μg). Among the 359 children, 133 (37%) experienced at least one severe exacerbation, and control was observed in 111 (31%) children. A multivariate logistic regression model demonstrated that age, season, and ICS dose are independent risk factors for exacerbation, whereas age is the only predictor of control. The odds ratio of exacerbation and control are 0.85 (95% CI, 0.78-0.92, p < .0001) and 0.85 (95% CI, 0.79-0.91, p < .0001) per year of increase in age, respectively. From infancy to adolescence, each year of life reduces per se the risk of a severe exacerbation by 15% and similarly increases the achievement of control in children treated for asthma.Journal of Asthma 11/2010; 48(1):65-8. · 1.52 Impact Factor -
Article: Lumen areas and homothety factor influence airway resistance in COPD.
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ABSTRACT: 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.Respiratory Physiology & Neurobiology 08/2010; 173(1):1-10. · 2.24 Impact Factor -
Article: Lung function impairment evidenced by sequential specific airway resistance in childhood persistent asthma: a longitudinal study.
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ABSTRACT: Specific airway resistance (sRaw) is virtually independent of lung growth, height, and gender, thus facilitating longitudinal follow-up. To assess whether a specific phenotype of asthmatic children with a decline in lung function can be evidenced using sRaw. 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. 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 (R(2) = .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. 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.Journal of Asthma 08/2010; 47(6):655-9. · 1.52 Impact Factor -
Article: Gas trapping is associated with severe exacerbation in asthmatic children.
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ABSTRACT: 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. 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). 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). 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.Respiratory medicine 08/2010; 104(8):1230-3. · 2.33 Impact Factor
Top co-authors
Top Journals
Institutions
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2006–2013
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Hôpital européen Georges-Pompidou – Hôpitaux universitaires Paris-Ouest
Paris, Ile-de-France, France
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2012
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Hôpital Armand-Trousseau – Hôpitaux universitaires Est Parisien
Paris, Ile-de-France, France
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2005–2010
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Université Paris Descartes
Paris, Ile-de-France, France
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2002–2006
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Assistance Publique – Hôpitaux de Paris
Paris, Ile-de-France, France -
Université Paris-Est Créteil Val de Marne - Université Paris 12
- Faculte de medecine
Créteil, Ile-de-France, France
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2002–2005
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Institut national de la santé et de la recherche médicale
Paris, Ile-de-France, France
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