Enhanced Electrochemical Performance in Supercapacitors through KCu-Cy Based Metal-Organic Framework Electrodes.

In the realm of electronics and electric energy storage, the convergence of organic and metallic materials has yielded promising outcomes. In this study, we introduce a novel metal-organic polymer synthesized from Cyamelurate and copper (KCu-Cy) and explore its application as an electrode for a supercapacitor. This material was pressed onto a stainless-steel grid as a thin film and synthesized on nickel foam. Comprehensive characterization was carried out to confirm the synthesis, ensure phase purity, and investigate atomic interactions. Single Crystal X-ray Diffraction (SCXRD) and Powder X-ray Diffraction (PXRD) analyses verified the synthesis and phase purity, shedding light on atomic arrangements. Fourier Transform Infrared Spectroscopy (FTIR) analyses provided insights into characteristic peaks within the material. Thermal Gravimetric Analysis (TGA) gauged stability and durability. Electrochemical performance was assessed through cyclic voltammetry. Notably, the nickel-supported electrodes, devoid of binders, exhibited exceptional specific capacity, reaching 1210.89 F/g at a scan rate of 5 mV/s, in contrast to 363.73 F/g for the pressed thin film on the stainless-steel grid, which incorporated a conductive agent and binder. Cu-Cy displayed impressive cyclization resistance, with a capacity retention of 90 % even after 11000 cycles. These findings underline the promise of Cu-Cy as a high-performance electrode material for supercapacitors, particularly in binder-free configurations, and suggest its potential in advanced energy storage applications.

Cross-sectional phenotyping of small airway dysfunction in preschool asthma using the impulse oscillometry system.

Objective. Asthma is a chronic inflammatory airway disorder known to induce small airways dysfunction (SAD). It is important to develop tools to assess the presence and extent of SAD in daily clinical practice. An Impulse Oscillometry System (IOS) might detect SAD, but the validity of the underlying model (serial Resistive airway and Compliant tissue model: RC model) in diseased lungs remains questionable.Methods. Our objective was to evaluate the usefulness of parameters obtained from six electrical circuit models that were fitted to the measurements of impedance obtained with IOS in asthmatic children characterized by an abnormal lung function defined by an increased baseline interrupter resistance (Rint, z-score > +1.645).Results. The six models were tested in 102 asthmatic children (median age: 5.5 years). Two models allowed the description of 92/102 (90%) children: 74 by the extended RIC model (central and peripheral Resistance, Inertance and peripheral airway Compliance) and 18 by the Mead1969 model (extended RIC plus lung compliance). Thus, peripheral airway compliance and resistance were essential to describe lung function abnormalities of these asthmatic children. Parenchyma impairment (increased lung compliance) which was responsive to salbutamol was present in 18% of asthmatic children. After salbutamol, peripheral airway resistance decreased while peripheral airway compliance increased, arguing for asthma-related SAD. R5-20Hz independently correlated with the two latter parameters but was increased in two thirds of children with increased Rint only.Conclusion. Additional modeling of IOS results can be a reliable tool to assess the presence and extent of SAD in young asthmatic children.

Non specific pattern of lung function in a respiratory physiology unit: causes and prevalence: results of an observational cross-sectional and longitudinal study.

BACKGROUND: ATS/ERS Task Force has highlighted that special attention must be paid when FEV1 and FVC are concomitantly decreased (<5th percentile) and the FEV1/FVC ratio is normal (>5th percentile) because a possible cause of this non specific pattern (NSP) is collapse of small airways with normal TLC measured by body plethysmography (>5th percentile). Our objectives were to determine the main lung diseases associated with this pattern recorded prospectively in a lung function testing (LFT) unit, the prevalence of this pattern in our LFT and among the diseases identified, and its development. METHODS: Observational study of routinely collected data selected from our Clinical Database Warehouse. RESULTS: The prevalence of NSP was 841/12 775 tests (6.6%, 95% CI: 6.2 to 7.0%). NSP was mainly associated with seven lung diseases: asthma (prevalence of NSP among asthmatics: 12.6%), COPD/emphysema (prevalence 8.6%), bronchiectasis (12.8%), sarcoidosis (10.7%), interstitial pneumonia (4.0%), pulmonary hypertension (8.9%) and bilateral lung transplantation for cystic fibrosis (36.0%). LFT measurements were described in 185 patients with NSP and indisputable nonoverlapping causes. A moderate defect (FEV1: 66 ± 9% predicted) with mild lung hyperinflation (FRC: 111 ± 27%, RV: 131 ± 33% predicted: suggesting distal airway obstruction) was evidenced whatever the underlying cause. A long term stability of NSP was evidenced in 130/185 patients (70% 95% CI: 64 to 77%). CONCLUSIONS: NSP is observed in asthma, COPD/emphysema, bronchiectasis, sarcoidosis, pulmonary hypertension, interstitial pneumonia and after bilateral lung transplantation and remains stable in the majority of patients.

Prevalence of overestimation or underestimation of the functional capacity using MRC score as compared to 6-minute walk test in patients with cardio-respiratory disorders.

OBJECTIVES: The first objective of our study was to assess whether patients diagnosed with cardio-respiratory disorders report overestimation or underestimation on recall (Medical Research Council (MRC) dyspnea scale) of their true functional capacity (walked distance during a 6-minute walk test (6MWT)). The second objective was to assess whether the measurement of breathlessness at the end of a 6MWT (Borg score) may help to identify dyspneic patients on recall. METHODS: The 6MWTs of 746 patients aged from 40 to 80 years who were diagnosed with either chronic obstructive pulmonary disease (COPD, n = 355), diffuse parenchymal lung disease (n = 140), pulmonary vascular diseases (n = 188) or congestive heart failure (n = 63) were selected from a prospective Clinical Database Warehouse. RESULTS: The percentage of patients who overestimated (MRC ≤ 2 with distance < lower limit of normal (LLN), 61/746, 8%; 95% confidence interval (CI): 6 to 10%) or underestimated (MRC > 2 with distance ≥LLN, 121/746, 16%; 95%CI: 14 to 19%) on recall their capacity was elevated. The overestimation seemed related to self-limitation, while the underestimation seemed related to patients who "work through" their breathing discomfort. These two latter groups of patients were mainly diagnosed with COPD. A Borg dyspnea score >3 (upper limit of normal) at the end of the 6MWT had 84% specificity for the prediction of a MRC score >1. CONCLUSION: Almost one fourth of patients suffering from cardio-pulmonary disorders overestimate or underestimate on recall their true functional capacity. An elevated Borg dyspnea score at the end of the 6MWT has a good specificity to predict dyspnea on recall.

Theoretical investigation of hydrogen sulfide capture from methane binary mixture using s-heptazine-based metal-organic framework.

CONTEXT: MOFs are promising candidates for the capture of H2S and CO2 from raw biogas. The presence of H2S residues in natural gas pipelines can cause corrosive damage and reduce energy efficiency. H2S capture from biogas presents several challenges due to its high toxicity and its corrosiveness. Microporous MOFs incorporating Lewis basic sites have demonstrated efficient capture of small and polar gas molecules such as CO2 and H2S from gas binary mixtures. In the quest to design and investigate functional materials to support the energy transition, specifically for the purification of RNG gas, we theoretically investigated the potential of s-heptazine-based IRH-1 for H2S capture from CH4 mixtures. IRH-1 exhibited significantly higher adsorption capacities for H2S (2.60 mmol/g) and CO2 (2.68 mmol/g) compared to CH4 (0.98 mmol/g) at 100 kPa and 298 K simulated by GCMC. All computed average energies for H2S were below 20 kJ/mol, indicating an exothermic physisorption behavior within the pores of IRH-1. IAST revealed remarkable H2S selectivity of IRH-1 for CH4/H2S binary mixtures at 5%, 10%, 15%, and 20% of H2S at 100 kPa. METHODS: GCMC simulations were performed with the BIOVIA Materials Studio 5.0 package using LJ potentials and UFF parameters to investigate the adsorption of pure H2S gas in the IRH-1 material. The IAST method was used to predict the adsorption behavior of H2S in different H2S/CH4 gas mixtures. The IAST calculations were performed using the Python package pyIAST, which allows the prediction of adsorption isotherms for mixed gases based on the adsorption isotherms for pure gases by numerical integration of the Gibbs adsorption approach.

Cross-sectional assessment of the roles of comorbidities in resting and activity-related dyspnea in severely obese women.

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 dyspnea complaints according to the presence of obesity-related comorbidities (asymptomatic airway hyperresponsiveness (AHR), asthma, gastroesophageal reflux disease (GERD) and sleep-disordered breathing (SDB)). We hypothesized that obese women can exhibit both resting and activity-related dyspnea, independently of the presence of asthma. METHODS: Severely obese (body mass index (BMI) > 35 kg m(-2)) women prospectively underwent description of resting and activity-related dyspnea (verbal descriptors and Medical Research Council (MRC) scale), pulmonary function testing (spirometry, absolute lung volumes, and methacholine challenge test), oesogastro-duodenal fibroscopy, and overnight polygraphy. Thirty healthy lean women without airway hyperresponsiveness were enrolled. RESULTS: Resting dyspnea 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 GERD while wheezing and cough were related to asthma only in obese women. Activity-related dyspnea was very prevalent (MRC score > 1, 75%), associated with obesity, with the exception of wheezing on exertion due to asthma. Asymptomatic AHR and SDB did not affect dyspneic complaints. CONCLUSIONS: In severely obese women referred for bariatric surgery, resting dyspnea complaints are observed in association with asthma or GERD, while activity-related dyspnea was mainly related to obesity only. Consequently, asthma does not explain all respiratory complaints of obese women.

Effect of Crystal Morphology on Electrochemical Performances of IRH-2 and IRH-2/PANI Composite for Supercapacitor Electrodes.

In the context of recent progress in designing metal-organic framework (MOF)-based supercapacitor electrodes, we report herein the successful growth of two different crystal morphologies of a cerium-based MOF, octahedral crystals named IRH-2-O and elongated square-bipyramidal crystals named IRH-2-ESBP (IRH = Institute de Recherche sur l'Hydrogène). The identical crystal structure of both materials was confirmed by powder X-ray diffraction (PXRD). Furthermore, scanning electron microscopy and energy-dispersive X-ray mapping analysis corroborated this fact and showed the crystal shape variation versus the surface composition of synthesized materials. Fourier transform infrared spectroscopy, UV-vis spectroscopy, and PXRD were used to confirm the purity of pristine MOFs as well as desired MOF//PANI composites. Cyclic voltammetry and electrochemical impedance spectroscopy highlighted the effect of crystal shape on the electrochemical performance of IRH-2 MOFs; the specific capacitance tripled from 43.1 F·g-1 for IRH-2-O to 125.57 F·g-1 for IRH-2-ESBP at 5 mV·s-1. The cycling stability was notably ameliorated from 7 K for IRH-2-O to 20 K for IRH-2-ESBP. Regarding the composites, the cell voltage was notably ameliorated from 1.8 to 1.95 V. However, the electrochemical performance of IRH-2/PANI composites was drastically decreased due to instability in the acidic media. To the best of our knowledge, our work is the first work that related the MOF crystal shape and the electrochemical performance.

Diffusing capacity for carbon monoxide is linked to ventilatory demand in patients with chronic obstructive pulmonary disease.

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.

S-Heptazine N-ligand based luminescent coordination materials: synthesis, structural and luminescent studies of lanthanide-cyamelurate networks.

Various series of lanthanide metal-organic networks denoted Ln-Cy (Ln = La, Ce, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb), were synthesized under solvothermal conditions using potassium cyamelurate (K3Cy) and lanthanide nitrate salts. All obtained materials were fully characterized, and their crystal structures were solved by single-crystal X-ray diffraction. Four types of coordination modes were elucidated for the Ln-Cy series with different Ln3+ coordination geometries. Structural studies were performed to compare the various coordination compounds of the Ln-Cy series. Moreover, the cyamelurate linkers of rich π-conjugated and uncoordinated Lewis basic sites were used as an absorbing chromophore to enhance the luminescence quantum efficiency, the band emission and the luminescence lifetime of the coordinated Ln metal centers. Solid-state UV-visible measurements combined with density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations were performed to further explore luminescent features of the Ln-Cy series and their origins.

Flexible and porous 2D layered structures based on mixed-linker metal-organic frameworks for gas sorption studies.

Layered structures of flexible mixed-linker metal-organic frameworks termed IRHs-(4 and 5) (IRH = Institut de Recherche sur l'Hydrogène) were synthesized by mixing cyclam, tetrakis(4-carboxyphenyl)benzene (TCPB), and copper and zinc metal salts respectively. The new materials characterized by single-crystal X-ray diffraction exhibited the features of HOFs and MOFs. Their structures are formed by coordination and hydrogen bonds that link metallocyclam (with Cu or Zn) and TCPB to a 2D sheet which is further packed to form a 3D structure with 1D microchannels. Remarkably, the as-synthesized IRHs-(4 and 5) contain DMF in the channels that can be exchanged with DCM and afterward removed from the framework by heating without losing their single-crystallinity. This enabled an easy elucidation of the structural transformations by single-crystal and powder X-ray diffraction analyses. Experimental studies of single-component adsorption isotherms of pure CO2, CH4, and N2 gases have been carried out for all activated IRHs. Based on the obtained adsorption isotherms, theoretical calculations using Ideal Adsorbed Solution Theory (IAST) have been performed to predict the selectivity of equimolar CO2/CH4 and CO2/N2 (1 : 1) binary mixtures. The simulations predicted outstanding selectivity for CO2/N2 than for CO2/CH4 at low pressures, reaching 185 for IRH-4 and 130 for IRH-5 at 1 bar.

Hydrogen Bond Patterns of Dipyridone and Bis(Hydroxypyridinium) Cations.

Dipyridonyl-substituted derivatives 2-4 of benzene, pyridine, and pyrazine, respectively, were synthesized to examine the ability of 2-pyridone and its protonated species to direct the self-assembly by hydrogen bonding. Structural analysis by single-crystal X-ray diffraction (SCXRD) of 2 and 4 in trifluoroacetic acid demonstrated that salts are formed as a result of the transfer of protons from the acid to the base (organic species) to generate a bis(hydroxypyridinium) dication. However, if no proton transfer takes place like in the case of crystals of 3 grown from DMSO/H2O, the self-assembly is mainly directed by the typical R 2 2(8) hydrogen bond motif of 2-pyridone. These results indicate that the process of converting a neutral 2-pyridonyl group into a hydroxypyridinium cation makes structure prediction difficult. Consequently, examination of proton transfer and assembly of dipyridone and its protonated species are of interest. In combination with SCXRD, Hirshfeld surface analysis (HSA) was also used to have a better understanding on the nature of intermolecular interactions within crystal structures of 2-4. The large number of F···H/H···F, H···O/O···H, H···H, and H···C/C···H contacts revealed by HSA indicates that hydrogen bonding and van der Waals interactions mainly contribute to crystal packing.

A Rational Design of Microporous Nitrogen-Rich Lanthanide Metal-Organic Frameworks for CO2/CH4 Separation.

Three new lanthanide metal-organic frameworks IRHs-(1-3) supported by cyamelurate linkers have been synthesized and structurally characterized. The incorporation of numerous heteroatoms (N and O) into the pore walls and the relatively small microchannels of these porous solids enhance bonding force of the host-guest interactions, thus promoting the adsorption of carbon dioxide (CO2) over methane (CH4). The nonpolar covalent bonds in methane also favor the less uptake due to the hydrophilic walls of these frameworks. Grand canonical Monte Carlo simulations were performed to determine the origin of the adsorption. The density isocontour surfaces show that CO2 is mainly adsorbed on the walls composed of organic linkers and around the metal sites, whereas no specific adsorption site is observed for CH4, which indicates weak interactions between the framework and the adsorbed gas. As expected, the simulations show that CH4 is not observed around the metal center due to the presence of H2O molecules. The excellent selectivity of CO2/CH4 binary mixture was predicted by the ideal adsorbed solution theory (IAST) via correlating pure component adsorption isotherms with the Toth model. At 25 °C and 1 bar, the CO2 and CH4 uptakes for IRH-3 were 2.7 and 0.07 mol/kg, respectively, and the IAST predicated selectivity for CO2/CH4 (1:1) reached 27, which is among the best value for MOF materials.

Cross-sectional study of loop gain abnormalities in childhood obstructive sleep apnea syndrome.

STUDY OBJECTIVES: We aimed to assess ventilatory control in typically developing children with and without obstructive sleep apnea (OSA). METHODS: Otherwise healthy children referred for suspicion of OSA were recruited. In addition to polysomnography, we analyzed loop, controller and plant gains (ie, LG, CG, and PG), which reflect the stability of control, chemoreceptor sensitivity and the pulmonary control of blood gases in response to changes in ventilation, respectively, from tidal breathing recordings during wakefulness. Two bivariate (ventilation, end-tidal CO2: one unconstrained and one constrained) and one trivariate (plus end-tidal oxygen) unconstrained model were used to assess model consistency and oxygen chemosensitivity. RESULTS: In sum, 54 children (median age 11.6 years) were included. Children with OSA (n = 19, [obstructive apnea-hypopnea index] OAHI ≥2.h-1) had a higher plant gain compared with those without OSA (n = 35), and it was positively correlated with apnea hypopnea index (AHI) (r2 = 0.10, p < 0.020). The two models showed consistent results. The bivariate constrained model showed that children with OAHI ≥5.h-1 showed an increased steady-state plant gain compared with children with OAHI <5.h-1. The trivariate model did not show evidence of any abnormality of oxygen chemosensitivity. CONCLUSION: Plant gain may contribute to OSA pathophysiology in children, and therapies directed at its reduction should be tested.

The utility of acoustic pharyngometry and rhinometry in pediatric obstructive sleep apnea syndrome.

OBJECTIVE: Our objective was to evaluate the usefulness of acoustic pharyngometry and rhinometry in assessing obstructive sleep apnea (OSA) syndrome in children. PATIENTS/METHODS: Patients who were hospitalized for polysomnography underwent acoustic pharyngometry and rhinometry in sitting and supine positions to measure anatomical (pharyngeal and nasopharyngeal) volumes and collapsibility characteristics (reduction of pharyngeal volume, estimated pharyngeal compliance, and reduction of nasopharyngeal volume). RESULTS: In this study, we prospectively enrolled 103 children (median age, 10.4 years; 47 girls). Measures obtained from rhinometry correlated with height and were further height-normalized whereas measures obtained from pharyngometry did not correlate with height. Sleep apnea was ruled out in 51 subjects, while 52 children fulfilled OSA criteria (35 with obstructive apnea-hypopnea index ≥ 2 and < 5.h-1 [mild] and 17 with an index ≥ 5). The three groups differed on the z-score of BMI, the reduction of pharyngeal volume when supine, the estimated pharyngeal compliance and the supine normalized nasopharyngeal volume. These four factors linearly correlated with the apnea index even though children without OSA and mild OSA were found to be similar overall. A multivariate analysis with apnea index as the dependent variable and BMI z-score, neck circumference, mean pharyngeal area in supine position, estimated pharyngeal compliance and normalized nasopharyngeal volume as independent variables, showed that only BMI z-score and estimated compliance remained independent predictors of obstructive apnea (r2 value = 0.25, p < 0.0001). CONCLUSION: An increase in pharyngeal compliance is an independent risk factor of OSA syndrome in children; it can be measured using acoustic pharyngometry while awake.

Bronchodilator Response Assessment of the Small Airways Obstructive Pattern.

BACKGROUND: A concomitant decrease in FEV1 and FVC with normal FEV1/FVC ratio and TLC defines small airways obstructive pattern (SAOP) and constitutes a classic pitfall of pulmonary-function-tests interpretation. OBJECTIVE: To evaluate the prevalence of flow- (FEV1 increase≥12% and 200 mL), volume- (FVC or inspiratory capacity [IC] increase≥12% and 200 mL), flow and volume-, and non-response to bronchodilation in patients with SAOP. An additional objective was to assess whether impulse oscillometry (IOS) parameters allow the diagnosis of SAOP and its reversibility. METHODS: Fifty consecutive adult patients with SAOP (FEV1 and FVC < lower limit of normal, FEV1/FVC and TLC > lower limit of normal) diagnosed on spirometry and plethysmography underwent the assessment of reversibility (400 µg salbutamol) on FEV1, FVC, IC and IOS parameters. RESULTS: The diseases most frequently associated with SAOP were COPD and asthma (26 and 15 patients, respectively). Six patients were flow-responders, 20 were volume-responders, 9 were flow and volume-responders and 15 patients were non-responders. Overall, 26 patients had a significant improvement of IC, and 35 / 50 (70%, 95%CI: 57-83) exhibited a significant bronchodilator response. The difference between Rrs5Hz and Rrs20Hz was increased in 28/50 patients (56%, 95%CI: 42-70 with value higher than upper limit of normal) and its decrease after bronchodilator significantly correlated to FEV1 increase only, suggesting proximal airway assessment. CONCLUSION: A significant reversibility, mainly assessed on IC increase, is frequent in Small Airways Obstructive Pattern. Impulse oscillometry is of limited value in this context because of its low sensitivity.

Loop gain in severely obese women with obstructive sleep apnoea.

Our objective was to assess whether obstructive sleep apnoea (OSA) patients were characterised by a reduced central CO2 controller gain (CG) and an enhanced plant gain (PG). We matched three groups of women (n=10 per group) enrolled in a previous study (Essalhi et al., J. Asthma. 50: 565-572, 2013): obese women with a respiratory disturbance index (RDI)≥15/h and with a RDI<15, and lean women without OSA (RDI<5). Tidal ventilation recordings during wakefulness with end-tidal PCO2 monitoring allowed the assessment of loop gain (LG) and its components (PG and CG). LG were similar for the three groups (p=0.844) while both PG and CG depicted significant differences (p=0.046 and p=0.011, respectively). Obese women with OSA were characterised by an increased PG and a reduced CG as compared to obese women without OSA. A negative relationship between CG and RDI (rho=-0.46, p=0.008) was evidenced. In conclusion, OSA in women is associated with a reduced central CO2 controller gain and an enhanced plant gain.

Efficacy and cost of home-initiated auto-nCPAP versus conventional nCPAP.

STUDY OBJECTIVES: To compare in a multicenter prospective study the efficacy and cost of conventional nasal continuous positive airway pressure (nCPAP) initiated at the sleep laboratory versus auto-nCPAP initiated at home. DESIGN: Patients with severe obstructive sleep apnea syndrome (OSAS) were randomized to treatment with either the REM+ auto device in constant mode at the effective pressure determined by titration at the sleep laboratory (n=17) or the REM+ auto device in automatic mode initiated at the patients home by a nurse (n=18). After 2 months, the efficacy and cost of nCPAP therapy and the time from diagnosis to nCPAP were evaluated. All values are reported as means +/- SD. PATIENTS: Thirty-five subjects with newly diagnosed OSAS (8 women and 27 men, mean age: 54.3 +/- 10.6 years, apnea-hypopnea index (AHI) 58.1 +/- 14.0 h(-1)). INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Both treatments were used properly and induced similar decreases in the AHI (7.6 +/- 6.9 vs. 10.4 +/ -12.5 h(-1) for auto-nCPAP and conventional nCPAP, respectively; NS) and Epworth Sleepiness score (from 15.5 +/- 4.7 to 7.5 +/- 3.4 vs. 14.7 +/- 3.9 to 7.6 +/- 3.4 for auto-nCPAP and conventional nCPAP, respectively; NS). With auto-nCPAP initiated at home, the time from diagnosis to final adjustment of nCPAP was shorter (16.3 +/- 5.0 vs. 47.2 +/- 46.5 days with conventional nCPAP, P < 0.02) and the cost was lower (1,263 +/- 352 vs. 1720+/-455 E, respectively; P < 0.05). CONCLUSIONS: Treatment of OSAS with auto-nCPAP initiated at home is effective and reliable and reduces the time from diagnosis to therapy and the cost of treatment.

Risk factors for airway hyperresponsiveness in severely obese women.

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: 39-57%) exhibited hyperresponsiveness (dose-response slope ≥2.39% decrease/µmol) that was independently and positively correlated with predicted % FRC, Raw0.5 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: 12-26%) 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 calibre and sigh frequency) is associated with hyperresponsiveness.

Activity-related dyspnea is not modified by psychological status in people with COPD, interstitial lung disease or obesity.

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.

Too rapid increase and too much breathlessness are distinct indices of exertional dyspnea in COPD.

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.