Insight into the relationship between forced vital capacity and transfer of the lungs for carbon monoxide in patients with idiopathic pulmonary fibrosis.

BACKGROUND: Forced vital capacity (FVC) is routinely used to quantify the severity and identify the progression of idiopathic pulmonary fibrosis (IPF). Although less commonly used, lung transfer of carbon monoxide (TLCO) correlates better with the severity of IPF than does FVC. METHODS: Aiming at studying how FVC behaves in relation to TLCO, we analysed cross-sectional data from 430 IPF patients, of which 221 had at least 2 assessments (performed 2.4 ± 1.9 years apart) available for longitudinal analyses. Thresholds for identifying "abnormal" FVC and TLCO values were the statistically-defined lower limits of normal (LLN). For patients with longitudinal data, mean annual absolute declines of FVC and TLCO were calculated. RESULTS: The correlation between FVC and TLCO (%predicted) was weak (R2=0.21). FVC was "abnormal" (i.e.,

Exercise hyperventilation and pulmonary gas exchange in chronic thromboembolic pulmonary hypertension: Effects of balloon pulmonary angioplasty.

BACKGROUND: Excessive ventilation (V̇E) and abnormal gas exchange during exercise are features of chronic thromboembolic pulmonary hypertension (CTEPH). In selected CTEPH patients, balloon pulmonary angioplasty (BPA) improves symptoms and exercise capacity. How BPA affects exercise hyperventilation and gas exchange is poorly understood. METHODS: In this longitudinal observational study, symptom-limited cardiopulmonary exercise tests and carbon monoxide lung diffusion (DLCO) were performed before and after BPA (interval, mean (SD): 3.1 (2.4) months) in 36 CTEPH patients without significant cardiac and/or pulmonary comorbidities. RESULTS: Peak work rate improved by 20% after BPA whilst V̇E at peak did not change despite improved ventilatory efficiency (lower V̇E with respect to CO2 output [V̇CO2]). At the highest identical work rate pre- and post-BPA (75 (30) watts), V̇E and alveolar-arterial oxygen gradient (P(Ai-a)O2) decreased by 17% and 19% after BPA, respectively. The physiological dead space fraction of tidal volume (VD/VT), calculated from measurements of arterial and mixed expired CO2, decreased by 20%. In the meantime, DLCO did not change. The best correlates of P(Ai-a)O2 measured at peak exercise were physiological VD/VT before BPA and DLCO after BPA. CONCLUSIONS: Ventilatory efficiency, physiological VD/VT, and pulmonary gas exchange improved after BPA. The fact that DLCO did not change suggests that the pulmonary capillary blood volume and probably the true alveolar dead space were unaffected by BPA. The correlation between DLCO measured before BPA and P(Ai-a)O2 measured after BPA suggests that DLCO may provide an easily accessible marker to predict the response to BPA in terms of pulmonary gas exchange.

Real-life association between inhaler technique, patient preference and asthma control in patients with uncontrolled asthma switched to budesonide/formoterol DuoResp® Spiromax® combination.

Objective: In asthma, treatment effectiveness is strongly influenced by the quality of inhaler use. New devices such as Spiromax® have been specifically developed to improve ease of use. It is crucial to determine whether switching to such a device improves inhaler technique and clinical outcomes, and to identify factors associated with handling errors.Methods: This observational study assessed inhaler device handling errors in 1435 asthma patients recruited via 135 participating physicians in France, before and after switching therapy from the Symbicort Turbuhaler® or Seretide® Diskus® to DuoResp® Spiromax®. Patients received training in the use of their new device at baseline and were re-assessed after three months.Results: After three months of use, 67% of patients were using the DuoResp® Spiromax® with no handling errors, and 88% with no critical errors. The presence of comorbidities was associated with handling errors overall. Concurrent illness potentially affecting device handling and previous training were associated with critical device handling errors. Most patients (85.4%) preferred DuoResp® Spiromax® over their previous device. Levels of inadequately controlled or uncontrolled asthma were reduced from baseline among patients using DuoResp® Spiromax® (8.6% versus 64.6%), and were higher in patients with critical handling errors.Conclusions: Effective patient education, correct inhaler technique, treatment adherence and devices associated with high patient satisfaction are interrelated factors key to the successful delivery of inhaled asthma therapy. Inhaler technique and patient device satisfaction should be routinely assessed in treated patients with uncontrolled asthma. Supplemental data for this article can be accessed at publisher's website.

A machine learning approach to predict extreme inactivity in COPD patients using non-activity-related clinical data.

Facilitating the identification of extreme inactivity (EI) has the potential to improve morbidity and mortality in COPD patients. Apart from patients with obvious EI, the identification of a such behavior during a real-life consultation is unreliable. We therefore describe a machine learning algorithm to screen for EI, as actimetry measurements are difficult to implement. Complete datasets for 1409 COPD patients were obtained from COLIBRI-COPD, a database of clinicopathological data submitted by French pulmonologists. Patient- and pulmonologist-reported estimates of PA quantity (daily walking time) and intensity (domestic, recreational, or fitness-directed) were first used to assign patients to one of four PA groups (extremely inactive [EI], overtly active [OA], intermediate [INT], inconclusive [INC]). The algorithm was developed by (i) using data from 80% of patients in the EI and OA groups to identify 'phenotype signatures' of non-PA-related clinical variables most closely associated with EI or OA; (ii) testing its predictive validity using data from the remaining 20% of EI and OA patients; and (iii) applying the algorithm to identify EI patients in the INT and INC groups. The algorithm's overall error for predicting EI status among EI and OA patients was 13.7%, with an area under the receiver operating characteristic curve of 0.84 (95% confidence intervals: 0.75-0.92). Of the 577 patients in the INT/INC groups, 306 (53%) were reclassified as EI by the algorithm. Patient- and physician- reported estimation may underestimate EI in a large proportion of COPD patients. This algorithm may assist physicians in identifying patients in urgent need of interventions to promote PA.

Concurrence of 1- and 3-Min Sit-to-Stand Tests with the 6-Min Walk Test in Idiopathic Pulmonary Fibrosis.

BACKGROUND: In idiopathic pulmonary fibrosis (IPF), some physiological parameters measured during a 6-min walk test (6-MWT) impart reliable prognostic information. Sit-to-stand tests (STSTs) are field exercise tests that are easier to implement than the 6-MWT in daily practice. OBJECTIVES: The aims of the study were to test the reproducibility and compare 2 STSTs (the 1-min STST [1-STST] and the semi-paced 3-min chair rise test [3-CRT]) in IPF, and to determine if selected physiological parameters (speed of displacement and changes in pulse oxygen saturation [SpO2]) are interchangeable between the STSTs and the 6-MWT. METHODS: Thirty-three patients with stable IPF were studied in 3 French expert centers. To test reproducibility, intra-class correlations (ICCs) of parameters measured during tests performed 7-14 days apart were calculated. To test interchangeability, the agreement and correlation of physiological responses measured during STSTs and during 6-MWT were studied. RESULTS: Vertical displacements and changes in SpO2 during both STSTs were reproducible, with ICCs ranging from 0.78 [0.63-0.87] to 0.95 [0.92-0.97]. Vertical displacements during 1-STST and 3-CRT were correlated with 6-MWT distance (correlation coefficients (r) of 0.72 and 0.77, respectively; p < 0.001). Similarly, correlations were found between changes in SpO2 measured during the 2 STSTs and the 6-MWT, with coefficients ranging from 0.73 to 0.91 (p < 0.001). Distance walked and SpO2 during 6-MWT were well estimated from vertical displacement and SpO2 during the 2 STSTs, respectively. CONCLUSION: The correlations found between the 2 STSTs and the 6-MWT suggest that STSTs may be of interest to assess displacement and exercise-induced changes in SpO2 in IPF patients.

Evaluation of the 3-minute chair rise test as part of preoperative evaluation for patients with non-small cell lung cancer.

BACKGROUND: Peak oxygen uptake ( V˙O2peak ) measured by a cardiopulmonary exercise test (CPX) is the gold-standard for predicting surgical risk in patients with non-small cell lung cancer (NSCLC). The 3-minute chair rise test (3CRT) is a simple test requiring minimal resources. This study aimed to determine the ability of 3CRT to predict V˙O2peak in patients with NSCLC. METHODS: Retrospective data from CPX and 3CRT carried out in 36 patients with NSCLC between March 2018 and February 2019 were included. A multivariate analysis was undertaken to derive a predictive V˙O2peak equation based on performance on the 3CRT. In addition, sensitivity-specificity analysis was carried out to estimate a threshold 3CRT value for the prediction of V˙O2peak ≥ 15 mL/kg/minute. RESULTS: The following equation was obtained: V˙O2peak predicted = (0.04765 × FEV1) - (0.207 59 × BMI) - (0.115 89 × age) + (0.386 09 × vertical distance) + 16.628 69; r2 = 0.75, P < 0.01. The bias between the V˙O2peak values predicted and measured during CPX was 0.0 ± 1.7 mL/kg/minute (95% limits of agreement [-3.5 to 3.5]). A performance ≥49 chair rises predicted V˙O2peak ≥ 15 mL/kg/minute with a sensitivity of 0.75 and a specificity of 0.81. CONCLUSIONS: The level of error in the prediction of V˙O2peak from 3CRT performance was too great to recommend that 3CRT should replace CPX as the sole measurement of V˙O2peak . Nevertheless, the 3CRT could help to identify those patients that require CPX prior to lung resection surgery for NSCLC, larger prospective study is needed to confirm this hypothesis. KEY POINTS: SIGNIFICANT FINDINGS OF THE STUDY: Cardiopulmonary exercise tests can stratify the surgical risk. Prediction of the peak oxygen uptake ( V˙O2peak ) value from the 3CRT yields an unacceptable level of error. However, a performance of 49 chair rises or more during the 3CRT could indicate a V˙O2peak ≥ 15 mL / kg / minute. WHAT THIS STUDY ADDS: The 3CRT is a useful screening tool to determine the necessity for a comprehensive cardiopulmonary exercise test, whose access is limited in clinical practice. It could also allow early screening of patients requiring specific prehabilitation programs.

Trends over time in COPD treatment choices by respiratory physicians: An analysis from the COLIBRI-COPD French cohort.

INTRODUCTION: Over the last decade, new evidence and many guidelines have been published on COPD pharmacological treatments; prescriptions are often not in accordance with guidelines. MATERIALS AND METHODS: Trends in physician treatment choices from February 2012 to November 2018 (Feb.2012/Nov.2018) were analyzed using data from COPD patients (spirometry-confirmed diagnosis) included in the COLIBRI-COPD cohort. Inhaled drug treatments (short- or long-acting ß2-agonist [SABA or LABA], short- or long-acting anticholinergic [SAMA or LAMA], or corticosteroid [ICS]) were classified into 5 treatment categories: "No initial maintenance treatment (IMT)" (untreated, or only SAMA or SABA); "1 long-acting bronchodilator (LABD)" (LABA or LAMA); "2 LABDs" (LABA + LAMA); "1 LABD + ICS" (LABA or LAMA + ICS); "2 LABDs + ICS" (LABA + LAMA + ICS). For the purpose of the study, 4 periods were defined to achieve balanced samples (T1-T4). RESULTS: Data from 4537 patients were collected. Over time, 3 major changes were observed: (1) an increase in treatment category "No IMT", mostly for GOLD 1 or GOLD A categories (GOLD A: from 19.1% at T1 to 41.2% at T4); (2) an increase in treatment category "2 LABDs" for GOLD 2 to 4 and GOLD A to D categories (GOLD B: from 15.4% to 29.7%); (3) a decrease in ICS use ("1 LABD + ICS" or "2 LABDs + ICS"), mostly for GOLD 1 to 3 and GOLD A categories (GOLD A, 2 LABDs + ICS: from 35.3% to 11.1%). CONCLUSION: Changes over time in therapeutic profiles suggest that new evidence from scientific publications and recommendations may have had a rapid impact on clinical practice.

Are there specific clinical characteristics associated with physician's treatment choices in COPD?

BACKGROUND: The number of pharmacological agents and guidelines available for COPD has increased markedly but guidelines remain poorly followed. Understanding underlying clinical reasoning is challenging and could be informed by clinical characteristics associated with treatment prescriptions. METHODS: To determine whether COPD treatment choices by respiratory physicians correspond to specific patients' features, this study was performed in 1171 patients who had complete treatment and clinical characterisation data. Multiple statistical models were applied to explain five treatment categories: A: no COPD treatment or short-acting bronchodilator(s) only; B: one long-acting bronchodilator (beta2 agonist, LABA or anticholinergic agent, LAMA); C: LABA+LAMA; D: a LABA or LAMA + inhaled corticosteroid (ICS); E: triple therapy (LABA+LAMA+ICS). RESULTS: Mean FEV1 was 60% predicted. Triple therapy was prescribed to 32.9% (treatment category E) of patients and 29.8% received a combination of two treatments (treatment categories C or D); ICS-containing regimen were present for 44% of patients altogether. Single or dual bronchodilation were less frequently used (treatment categories B and C: 19% each). While lung function was associated with all treatment decisions, exacerbation history, scores of clinical impact and gender were associated with the prescription of > 1 maintenance treatment. Statistical models could predict treatment decisions with a < 35% error rate. CONCLUSION: In COPD, contrary to what has been previously reported in some studies, treatment choices by respiratory physicians appear rather rational since they can be largely explained by the patients' characteristics proposed to guide them in most recommendations.

Minimal clinically important difference of 3-minute chair rise test and the DIRECT questionnaire after pulmonary rehabilitation in COPD patients.

BACKGROUND: The 3-minute chair rise test (3-minute CRT) and the Disability Related to COPD Tool (DIRECT) are two reproducible and valid short tests that can assess the benefit of pulmonary rehabilitation (PR) in terms of functional capacity and dyspnea in everyday activities. METHODS: We determined the minimal clinically important difference (MCID) of the DIRECT questionnaire and 3-minute CRT using distribution methods and anchor encroaches with a panel of eight standard tests in a cohort of 116 COPD patients who completed a PR program in real-life settings. RESULTS: The estimated MCID for the 3-minute CRT and DIRECT scores was five repetitions and two units, respectively, using separate and combined independent anchors. The all-patient (body mass index-obstruction-dyspnea-exercise [BODE] scores 0-7), BODE 0-2 (n=42), and BODE 3-4 (n=50) groups showed improvements greater than the MCID in most tests and questionnaires used. In contrast, the BODE 5-7 group (n=24) showed improvements greater than MCID in only the 3-minute CRT, 6-minute walk test, endurance exercise test, and DIRECT questionnaire. DISCUSSION AND CONCLUSION: This study demonstrates that the short and simple DIRECT questionnaire and 3-minute CRT are responsive to capture the beneficial effects of a PR program in COPD patients, including those with severe disease. TRIAL REGISTRATION NUMBER: NCT03286660.

COPD treatment pathways in France: a retrospective analysis of electronic medical record data from general practitioners.

BACKGROUND: Increasing availability of therapeutic options for COPD may drive new treatment pathways. This study describes COPD treatment in France, focusing on identifying initial treatment modifications in patients with COPD who either initiated long-acting bronchodilator (LABD)-based therapy or escalated to triple therapy (long-acting muscarinic antagonist [LAMA] + long-acting ß2-agonist [LABA] + inhaled corticosteroid [ICS]). METHODS: This retrospective analysis of patients with COPD in a large general practitioner database (IQVIA Longitudinal Patient Database) in France included two cohorts: Cohort 1 - new initiators of LABD-based therapy (LAMA, LABA, LAMA + LABA, LAMA + ICS, LABA + ICS or LAMA + LABA + ICS); Cohort 2 - patients escalating to triple therapy from mono- or dual-bronchodilator-based maintenance treatment. Both cohorts were indexed on the date of initiation/escalation (January 2008-December 2013), and the first treatment modification (at class level) within the 18-month post-index observational period was described. Five mutually exclusive outcomes were defined: continuous use (no modification), discontinuation (permanent [≥91 days with no restart] or temporary [≥91 days with subsequent restart]), switch, and augmentation (Cohort 1 only). Exploratory analysis of Cohort 1 explored potential drivers of treatment initiation. RESULTS: Overall, 5,065 patients initiated LABD-based therapy (Cohort 1), and 501 escalated to triple therapy (Cohort 2). In Cohort 1, 7.0% of patients were continuous users, 46.5% discontinued permanently, 28.5% discontinued temporarily, 2.8% augmented (added LAMA and/or LABA and/or ICS), and 15.2% switched therapy. In Cohort 2, 18.2% of patients were continuous users, 7.2% discontinued permanently, 27.9% discontinued temporarily, and 46.7% switched therapy. Exploratory analyses showed that time since COPD diagnosis was first recorded, pre-index exacerbation events, and concomitant medical conditions were potential drivers of initial maintenance treatment choices. CONCLUSION: Discontinuation among new initiators of LABD-based therapy was high in France, whereas few switched or augmented treatment. In comparison, permanent discontinuation within 18 months was low in patients escalating to triple therapy.

The multidimensional nature of dyspnoea in amyotrophic lateral sclerosis patients with chronic respiratory failure: Air hunger, anxiety and fear.

BACKGROUND: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder leading to chronic respiratory failure. Few studies have investigated ALS-related dyspnoea, and none have characterised the emotional distress it inflicts. We hypothesised that ALS-related dyspnoea has a strong affective component that relates to quality of life. METHODS: This prospective, observational study was conducted in 41 ALS patients >18 with chronic respiratory failure and an indication for noninvasive ventilation (NIV). Dyspnoea was assessed using the Multidimensional Dyspnea Profile (MDP) at baseline and 1 month after NIV initiation. Correlations between scores evaluating the sensory and affective dimensions of dyspnoea and other patient-reported outcomes and pulmonary function tests were analysed. RESULTS: Dyspnoea was described as intense (median [IQR] score on a 0-10 scale: 6.5 [4.0-7.5]). The sensory dimension of dyspnoea was polymorphic, but «air hunger¼ was the most common (48.8%) and the most intense (6 [4-8]) sensory descriptor. In the affective domain, most patients rated «anxious¼ (85.4%) and «afraid¼ (60.9%) above 0. The MDP affective dimension correlated significantly with other patient-reported outcomes, with the strongest correlation being between MDP «anxious¼ and the anxiety component of the Hospital Anxiety Depression Scale (Pearson's R = 0.70). One month after initiation of NIV, dyspnoea during unassisted breathing was described in virtually the same terms, particularly the affective dimension. DISCUSSION: ALS-related dyspnoea is intense and fear-provoking, persists during unassisted breathing between NIV sessions, and significantly impacts health-related quality of life. This study highlights the need for increased awareness of and research into ALS-related dyspnoea.

Physiologic Determinants of Exercise Capacity in Pulmonary Langerhans Cell Histiocytosis: A Multidimensional Analysis.

BACKGROUND: Reduced exercise capacity severely impacts quality of life in pulmonary Langerhans cell histiocytosis. Ascertaining mechanisms that impair exercise capacity is necessary to identify targets for symptomatic treatments. METHODS: Dyspnea, pulmonary function tests and cardiopulmonary exercise test were analysed in 62 study participants. Data were compared between subjects with impaired and normal aerobic capacity (V'O2 peak less than 84% versus 84% predicted or more). Data were reduced using a principal component analysis. Multivariate analysis included V'O2 peak as the dependent variable and principal components as covariates. RESULTS: V'O2 peak was reduced in 44 subjects (71%). Subjects with impaired aerobic capacity presented: (i) decreased FEV1, FVC, FEV1/FVC, DLCO and DLCO/VA and increased AaDO2, (ii) increased ventilatory equivalents at ventilatory threshold, VD/VT peak, AaDO2 peak and PaCO2 peak and decreased ventilatory reserve and PaO2 peak. There was no difference between groups in dyspnea scores. Principal component analysis extracted 4 principal components interpreted as follows: PC1: gas exchange; PC2: "pseudorestriction"; PC3: exercise-induced hyperpnea; PC4: air trapping. Multivariate analysis explained 65% of V'O2 peak. The 4 principal components were independently associated with V'O2 peak (ßcoefficients: PC1: 9.3 [4.6; 14], PC2: 7.5 [3; 11.9], PC3: -5.3 [-9.6;-1.], PC4: -9.8 [-14,9;-4.7]). CONCLUSION: Impaired exercise capacity is frequent in pulmonary Langerhans cell histiocytosis. It is mainly caused by pulmonary changes but is not associated with increased dyspnea intensity. Therefore, treating the lung represents a relevant approach for improving exercise capacity, even in patients experiencing mild dyspnea.

Real-life assessment of the multidimensional nature of dyspnoea in COPD outpatients.

Dyspnoea is a prominent symptom of chronic obstructive pulmonary disease (COPD). Recent multidimensional dyspnoea questionnaires like the Multidimensional Dyspnea Profile (MDP) individualise the sensory and affective dimensions of dyspnoea. We tested the MDP in COPD outpatients based on the hypothesis that the importance of the affective dimension of dyspnoea would vary according to clinical characteristics.A multicentre, prospective, observational, real-life study was conducted in 276 patients. MDP data were compared across various categories of patients (modified Medical Research Council (mMRC) dyspnoea score, COPD Assessment Test (CAT) score, Global Initiative for Chronic Obstructive Lung Disease (GOLD) airflow obstruction categories, GOLD "ABCD" categories, and Hospital Anxiety and Depression Scale (HADS)). Univariate and multivariate regressions were conducted to explore factors influencing the affective dimension of dyspnoea. Cluster analysis was conducted to create homogeneous patient profiles.The MDP identified a more marked affective dimension of dyspnoea with more severe mMRC, CAT, 12-item Short-Form Health Survey mental component, airflow obstruction and HADS. Multivariate analysis identified airflow obstruction, depressive symptoms and physical activity as determinants of the affective dimension of dyspnoea. Patients clustered into an "elderly, ex-smoker, severe disease, no rehabilitation" group exhibited the most marked affective dimension of dyspnoea.An affective/emotional dimension of dyspnoea can be identified in routine clinical practice. It can contribute to the phenotypic description of patients. Studies are needed to determine whether targeted therapeutic interventions can be designed and whether they are useful.

A simple semipaced 3-minute chair rise test for routine exercise tolerance testing in COPD.

The functional work capacity of chronic obstructive pulmonary disease (COPD) patients is usually assessed with walk tests such as the 6-minute walk test (6MWT) or the shuttle test. Because these exercise modalities require a controlled environment which limits their use by pulmonologists and severely restricts their use among general practitioners, different modalities of a short (1 minute or less) sit-to-stand test were recently proposed. In this study, we evaluated a new modality of a semipaced 3-minute chair rise test (3CRT) in 40 patients with COPD, and compared the reproducibility of physiological responses and symptoms during the 3CRT and their interchangeability with the 6MWT. The results demonstrate that physiological variables, heart rate, pulse oxygen saturation, work done, and symptoms (Borg dyspnea and fatigue scores), during the 3CRT were highly reproducible, and that the physiological responses and symptoms obtained during the 3CRT and the 6MWT were interchangeable for most patients. Moreover, these preliminary data suggest that patients able to perform more than 50 rises during 3 minutes had no significant disability. The simplicity and ease of execution of the 3CRT will facilitate the assessment of exercise symptoms and disability in COPD patients during routine consultations with pulmonologists and general practitioners, and will thus contribute to the improved management of COPD patients.

Diagnosis and management of idiopathic pulmonary fibrosis: French practical guidelines.

Idiopathic pulmonary fibrosis (IPF) is the most frequent chronic idiopathic interstitial pneumonia in adults. The management of rare diseases in France has been organised by a national plan for rare diseases, which endorsed a network of expert centres for rare diseases throughout France. This article is an overview of the executive summary of the French guidelines for the management of IPF, an initiative that emanated from the French National Reference Centre and the Network of Regional Competence Centres for Rare Lung Diseases. This review aims at providing pulmonologists with a document that: 1) combines the current available evidence; 2) reviews practical modalities of diagnosis and management of IPF; and 3) is adapted to everyday medical practice. The French practical guidelines result from the combined efforts of a coordination committee, a writing committee and a multidisciplinary review panel, following recommendations from the Haute Autorité de Santé. All recommendations included in this article received at least 90% agreement by the reviewing panel. Herein, we summarise the main conclusions and practical recommendations of the French guidelines.

Reduction of maximal oxygen uptake in sarcoidosis: relationship with disease severity.

BACKGROUND: Patients with sarcoidosis frequently exhibit exertional dyspnea. Although the functional limitation might be related to ventilatory problems, some patients exhibited exertional dyspnea without significant abnormalities of pulmonary function tests (PFT). Therefore, the mechanisms responsible for exercise intolerance remain unclear. OBJECTIVES: The aim of this retrospective study was to determine the mechanisms responsible for exercise intolerance. METHODS: Cardiopulmonary exercise testing (CPET) was performed in 157 dyspneic sarcoid patients (stage I: 29; stage II-III: 95; stage IV: 33) and VO2 peak was correlated with radiological stage and resting PFT. RESULTS: VO2 peak was decreased in 73% patients, did not differ according to radiological stage and was correlated with VC, FVC, FEV1, TLC and DLCO. FVC was the major significant predictor of VO2 peak explaining 17% of VO2 variation. Among CPET variables, peak heart rate and VE/VO2 at ventilatory threshold explained 22% of VO2 alteration in stage I and stage II-III, and 9% in stage IV. In stage IV, V(D)/V(T) peak explained 41% of VO2 alteration. CONCLUSION: In conclusion, in the lower stages circulatory impairment and impaired heart rate response to exercise are involved in the exercise capacity limitation, whereas in stage IV the ventilatory and gas exchange impairment may be more important. CPET must be performed to accurately characterize the mechanisms responsible for exercise limitation and help the clinician in the management of the disease.

Detection of disturbances in pulmonary gas exchanges during exercise from arterialized earlobe PO2.

Blood sampling from the arterialized earlobe is widely used in clinical exercise testing but Fajac et al. (1998) (Eur. Respir. J. 11, 712-715) have shown that arterialized P(O2) Pc(CO2) is not a valid surrogate for Pa(O2). In the present study, in order to detect disturbances in pulmonary gas exchanges during clinical exercise testing from the alveolar-arterial gradient of P(O2) (P[Ai-a](O2)), a correction factor for Pc(O2) was validated from data on a large cohort (107 patients at one or two levels of exercise: 172 pairs of samples). Pulmonary gas exchanges and pH, P(O2), P(CO2), PA(iO2) and P(Ai-a)(O2) from arterial and arterialized blood were measured or computed. Arterial and arterialized pH and P(CO2) (and thus PA(iO2)) were similar but P(CO2) was lower than arterial P(O2) (Pa(O2)). However, when corrected for the systematic bias between Pa(O2) and Pc(O2), which increased with Pc(O2), Pc(O2) adequately detected disturbances in pulmonary gas exchanges with a very high sensibility and specificity (predictive values of a negative or positive test ∼95%).