Antoine Cuvelier

Dependency on mask ventilation after acute respiratory failure in the intermediate care unit

The predictive factors for long-term dependency (LTD) on noninvasive ventilation (NIV) immediately after acute hypercapnic respiratory failure (AHRF) have not been identified. The present authors studied 42 patients with chronic obstructive pulmonary disease (COPD) and 58 non-COPD patients successfully treated by NIV for an AHRF episode. Parameters at stable state, at admission for AHRF and during a 1-yr follow-up were compared in patients with or without LTD-NIV at discharge. The incidence of LTD-NIV was 39% in non-COPD patients and 19% in COPD patients. Based on multivariate analysis with stepwise logistic regression, lower baseline pH values and noninfectious causes of AHRF were independently associated with LTD-NIV. Mutually adjusted odds ratios were found to be 1.316 (95% confidence interval (CI) = 1.127–1.536) for a 0.01 decrease of baseline pH value and 5.1 (95% CI = 1.8–14.0) for a noninfectious cause of AHRF. Outcome after 1 yr was poor in COPD patients. Long-term dependency on noninvasive ventilation is not an uncommon situation after resolution of an acute hypercapnic respiratory failure episode, especially in patients with non-chronic obstructive pulmonary disease causes of respiratory failure. The present study raises the need for prospective validation of a weaning protocol in patients managed by noninvasive ventilation for an acute hypercapnic respiratory failure episode.

A noninvasive method to identify ineffective triggering in patients with noninvasive pressure support ventilation.

Background: Ineffective inspiratory triggering efforts are a major cause of poor patient-ventilator interactions during mechanical ventilation, but their routine identification requires the insertion of an esophageal catheter. Objectives: We developed a mathematical analysis of ventilatory tracings recorded under noninvasive pressure ventilation in order to identify ineffective triggering efforts and their consequences without recording esophageal pressure. Methods: We assessed 2,183 cycles from 44 pressure support tracings in 14 children with cystic fibrosis treated by noninvasive home ventilation. Airway pressure, flow and esophageal pressure time series were visually analyzed and manually counted. Airway pressure versus time and flow versus time were then analyzed using a dedicated algorithm written by us. Esophageal pressure was only used for validation. Results: A mathematical treatment of flow time series allowed us to draw phase portraits that had specific periodic trajectories for triggered ventilatory cycles and ineffective triggering efforts. From flow and pressure tracings, our algorithm correctly identified 100% of triggered cycles and 53/56 (94.6%) of ineffective triggering efforts. Ineffective triggering was associated with a significant reduction in minute ventilation, inspiratory flows and a significant increase in inspiratory efforts. Conclusions: A noninvasive analysis of flow and airway pressure can reliably identify ineffective triggering efforts during noninvasive pressure support ventilation. This approach may be a valuable tool for evaluating patient-ventilator interactions and their consequences during long-term recordings.

Domiciliary Non-invasive Ventilation in COPD: An International Survey of Indications and Practices

Abstract Despite the fact that metanalyses and clinical guidelines do not recommend the routine use of domiciliary non-invasive ventilation (NIV) for patients diagnosed with severe stable Chronic Obstructive Pulmonary Disease (COPD) and with chronic respiratory failure, it is common practice in some countries. We conducted an international web-survey of physicians involved in provision of long-term NIV to examine patterns of domiciliary NIV use in patients diagnosed with COPD. The response rate was 41.6%. A reduction of hospital admissions, improvements in quality of life and dyspnea relief were considered as the main expected benefits for patients. Nocturnal oxygen saturation assessment was the principal procedure performed before NIV prescription. Recurrent exacerbations (>3) requiring NIV and failed weaning from in hospital NIV were the most important reasons for starting domiciliary NIV. Pressure support ventilation (PSV) was the most common mode, with “low” intensity settings (PSV-low) the most popular (44.4 ± 30.1%) compared with “high” intensity (PSV-high) strategies (26.9 ± 25.9%), with different geographical preferences. COPD is confirmed to be a common indication for domiciliary NIV. Recurrent exacerbations and failed weaning from in-hospital NIV were the main reasons for its prescription.

Ventilation à domicile chez les patients atteints de bronchopneumopathie chronique obstructive (BPCO)

Resume Introduction La bronchopneumopathie chronique obstructive (BPCO) est un motif croissant d’indication a la ventilation a domicile (VAD) souvent par une ventilation non invasive (VNI). Cette revue generale a pour objectif de detailler les elements physiopathologiques et les resultats des etudes cliniques qui etayent aujourd’hui les recommandations des societes savantes internationales. Etat des connaissances Les etudes publiees ne sont pas toujours controlees, sont souvent de trop courte duree ou grevees d’aleas methodologiques importants. Les deux etudes controlees et de duree ≥ 12 mois sont concordantes pour suggerer que la VNI n’ameliore pas la survie. En consequence, une VAD peut etre envisagee en situation d’echec de l’oxygenotherapie de longue duree, dans un contexte d’aggravation progressive de l’etat clinique et respiratoire et la survenue de frequents episodes d’insuffisance respiratoire aigue hypercapnique. La presence d’une hypercapnie diurne ≥ 55 mmHg (7,3 kPa) est une condition necessaire mais non suffisante pour indiquer ce traitement. Conclusion La VAD ne doit etre envisagee que chez des patients selectionnes, pour lesquels la symptomatologie clinique et la frequence des exacerbations doivent etre pris en compte. Dans l’attente d’une caracterisation des patients repondeurs, une re-evaluation reguliere du traitement est necessaire au decours.

COPD and perception of the new GOLD document in Europe. Workshop from the Société de pneumologie de langue française (SPLF)

INTRODUCTION The organization of care for chronic non-infectious diseases, notably COPD, is a common preoccupation in developed countries in which this disease is among the main causes of mortality and disability. We report a summary of a workshop organized on this theme in April 2013 by the Société de pneumologie de langue française. BACKGROUND Experts from several European countries presented the organizational practices for the management of COPD in their countries, in particular the detection of the disease and the systems of care. The common objectives were to obtain better motivation to stop smoking, earlier detection of the disease and education in the recognition of the signs of exacerbation and their severity. The experts agreed that mass detection is of little benefit and difficult to organize. Early individual screening is preferable on the basis of precise, easily identified criteria. The classification recommended by the GOLD committee since 2011 does not seem to be adopted universally throughout Europe. If there is a real improvement over the previous classification due to taking into account clinical criteria, quality of life and exacerbations, criticisms have arisen concerning the choice of certain pathways and therapeutic recommendations not based on prospective studies with a high level of evidence. CONCLUSION European experiences concerning the management of COPD are varied and complementary. One remaining question is who to screen: all subjects at risk (all smokers, all occupations at risk), only symptomatic subjects, subjects with severe and disabling symptoms?

Health-Related Quality of Life in Patients with Alpha-1 Antitrypsin Deficiency: The French Experience

Abstract The French registry of patients with alpha-1 antitrypsin deficiency (AATD)-associated emphysema was launched in 2006. Here, we aimed to report on the baseline characteristics of these patients, their health-related quality of life (HRQoL) and factors associated with HRQoL. Another goal was to survey the practices of French physicians regarding augmentation therapy. We included 273 patients with AATD, emphysema, obstructive-pattern [forced expiratory volume in 1 sec/forced volume capacity (FEV1/FVC) < 0.7], FEV1 ≤ 80% predicted. Mean (SD) age was 51.8 (11.1) years, 240 (87.9%) of patients were smokers or ex-smokers, mean (SD) FEV1 was 40.5% (15.7) predicted. Mean (SD) SGRQ score was 49.0 (20.0) and was higher for females than males (52.7 [20.7] vs 46.8 [18.2]; p = 0.01). Dyspnea showed the strongest association with SGRQ score (r = 0.65; p < 0.0001), followed by chronic bronchitis (r = 0.33; p < 0.0001) and wheezing (r = 0.32; p < 0.0001). Number of exacerbations in the year before inclusion was also significantly associated with SGRQ score (r = 0.36; p < 0.0001). The SGRQ score was associated with the 6-min walking distance (r = –0.53, p < 0.0001), FEV1 (% predicted, r = –0.53, p < 0.0001) and DLCO (% predicted, r = –0.52, p < 0.0001). It was also associated with the GOLD 2006 (r = 0.53; p < 0.0001) and GOLD 2011 (r = 0.63; 
p < 0.0001) classifications and with the BODE index (r = 0.37; p < 0.0001). Age, history of tobacco smoking or current smoking did not show any association with SGRQ total scores. On multivariate analysis, a model including age, chronic bronchitis, dyspnea (MRC scale), diffusing lung capacity and 6-min walking distance explained 57% of the variation in the score. The French registry provides important insights into the clinical characteristics of French patients with AATD-related emphysema.

Performance of the BODE index in patients with α1-antitrypsin deficiency-related COPD

The BODE (body mass index, airflow obstruction, dyspnoea and exercise capacity) index is used to decide on referral and transplantation of patients with chronic obstructive pulmonary disease (COPD). The BODE index has not been validated in patients with &agr;1-antitrypsin deficiency, who account for 15% of COPD patients undergoing lung transplantation. We sought to validate the BODE index in &agr;1-antitrypsin deficiency-related COPD. We assessed the prognostic value of the BODE index in 191 patients followed from 2006 to 2012 in a French prospective cohort of patients with &agr;1-antitrypsin deficiency. 20 patients died during follow-up and 22 underwent lung transplantation. Survival (95% CI) was 93.0% (91.7–94.3%) at 3 years and 76.0% (72.9–79.1%) at 5 years. The 3-year survival was 97.4% (96.6–98.2%), 98.0% (96.7–99.3%), 87.7% (84.5–90.9%) and 75.3% (66.0–84.6%) for patients with BODE index 0–2, 3–4, 5–6 and 7–10, respectively. Survival discrimination of the BODE index was better than with both forced expiratory volume in 1 s and Global Initiative for Chronic Obstructive Lung Disease classification. Regarding calibration, expected survival by BODE index was noticeably lower than observed survival. The BODE index showed very good survival discrimination in patients with &agr;1-antitrypsin deficiency-related COPD. Larger studies are needed to support its use to drive patient referral for lung transplantation. Larger studies are needed to support the use of the BODE index to drive patient referral for lung transplantation http://ow.ly/t4lmg

Traduction française et adaptation culturelle du questionnaire SRI. Questionnaire de qualité de vie liée à la santé des patients insuffisants respiratoires chroniques traités par ventilation à domicile

INTRODUCTION We performed the French translation and cross-cultural adaptation of the Severe Respiratory Insufficiency (SRI) questionnaire. Written and validated in German, this questionnaire evaluates health-related quality of life in patients treated with domiciliary ventilation for chronic respiratory failure. METHODS Four bilingual German-French translators and a linguist were recruited to produce translations and back-translations of the questionnaire constituted of 49 items in seven domains. Two successive versions were generated and compared to the original questionnaire. The difficulty of the translation and the naturalness were quantified for each item using a 1-10 scale and their equivalence to their original counterpart was graded from A to C. The translated questionnaire was finally tested in a pilot study, which included 15 representative patients. RESULTS The difficulty of the first translation and the first back-translation was respectively quantified as 2.5 (range 1-5.5) and 1.5 (range 1-6) on the 10-point scale (P=0.0014). The naturalness and the equivalence of 8/49 items were considered as insufficient, which led to the production of a second translation and a second back-translation. The meanings of two items needed clarification during the pilot study. CONCLUSION The French translation of the SRI questionnaire represents a new instrument for clinical research in patients treated with domiciliary ventilation for chronic respiratory failure. Its validity needs to be tested in a multicenter study.

DYNAMICS UNDERLYING PATIENT-VENTILATOR INTERACTIONS DURING NOCTURNAL NONINVASIVE VENTILATION

Noninvasive ventilation is a common procedure for managing patients having chronic respiratory failure. The success of this ventilatory assistance is often linked with patients tolerance that is known to be related to the quality of the synchronization between patients spontaneous breathing cycles and ventilatory cycles delivered by the ventilator. Thirty-four sleep sessions (more than 5000 ventilatory cycles each) were automatically investigated using a specific algorithm processing airflow and pressure time series. Four groups of patients were defined according to the interplay between asynchrony events and leaks. Different mechanisms that depend on sleep stages were thus evidenced. A Shannon entropy was also proposed as a new sleep fragmentation quantification methodology.

Substitution of Carbonate by Acetate Buffer for IGG Coating in Sandwich Elisa

The first step of sandwich ELISA, namely adsorption of antibodies to plastic microtiter plates, was studied as a function of the pH of the coating buffer. Coating efficiency was assessed in terms of maximum signal (absorbance) observed in ELISA and also estimated by measuring the amount of functional antibodies adsorbed to the plate. While goat antibodies displayed better results after coating with acetate pH 5 buffer, rabbit IgGs generally worked well at pH 7.4. On average, the classical carbonate pH 9.6 buffer was only 50% as efficient.