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The obesity hypoventilation syndrome (OHS) has an increasing prevalence. Compliance with first-line non-invasive ventilation has not been evaluated, taking into account patients' initial comorbidities. This study consisted of identification of the factors associated with compliance with non-invasive ventilation during the first six months of use.A monocentric retrospective study, gathering patients from the pneumology department of Gabriel-Montpied hospital in Clermont-Ferrand, from April 2010 to October 2019. The analysis was carried-out through the collection of computerised medical records (age, mode of entry, patient comorbidities) and compliance reports (average daily hours of use) provided by the regional service provider for the Auvergne area (AIRRA).Being hospitalized for an acute exacerbation and being older than seventy-five years were factors associated with an improved compliance to non-invasive ventilation, with an increase of 1.47h/d and 2.73h/d (P value: 0.018 and 0.02, respectively). Moreover, patients with obstructive sleep apnea hypopnea syndrome and recipients of therapeutic education may prove more compliant over time.Age greater than seventy-five years and being hospitalized for an acute exacerbation are predictors of better use of non-invasive ventilation in OHS.

In childhood and adolescence overweight is defined as a body mass index (BMI) above the 97th percentile for age and sex, according to the curves established by the International Obesity Task Force (IOTF). In France, it is estimated that 25 % of children under 18 years old are overweight. Overweight and obesity in this population are multifactorial, with an important influence of genetic factors, modulated by pre and post-natal (maternal smoking), societal and psychological determinants. The impact of obesity on respiratory function in children is mostly characterized by a decreased FEV1/FCV. Moreover, several studies have shown an association between asthma and overweight/obesity, with a pejorative impact of BMI on asthma control. However, asthma is still poorly characterized in this population, and the determinants of bronchial obstruction seem to differ from non-obese children, with less eosinophilic inflammation. Obstructive sleep apnea syndrome (OSAS) is a frequent complication of obesity, affecting up to 80% of obese children and adolescents. It has a specific polysomnographic definition in children. Symptoms are similar to adult OSAS, but with cognitive and neurobehavioral alterations often more important in adolescents. The treatment consists in ENT surgery when indicated (with systematic post-operative polysomnography), and nocturnal continuous positive airway pressure (CPAP). The obesity-hypoventilation syndrome (OHS) has the same definition in children as in adults and affects up to 20% of obese patients. Treatment consists in nocturnal ventilation using bilevel positive airway pressure (BiPAP). Finally, in some extreme cases, bariatric surgery can be performed. The indication should be discussed in a specialised paediatric reference centre.

The obese patient is at an increased risk of perioperative complications. Most importantly, these include difficult access to the airways (intubation, difficult or impossible ventilation), and post-extubation respiratory distress secondary to the development of atelectasis or obstruction of the airways, sometimes associated with the use of morphine derivatives. The association of obstructive sleep apnea syndrome (OSA) with obesity is very common, and induces a high risk of peri- and postoperative complications. Preoperative OSA screening is crucial in the obese patient, as well as its specific management: use of continuous positive pre, per and postoperative pressure. For any obese patient, the implementation of protocols for mask ventilation and/or difficult intubation and the use of protective ventilation, morphine-sparing strategies and a semi-seated positioning throughout the care, is recommended, combined with close monitoring postoperatively. The dosage of anesthetic drugs should be based on the theoretical ideal weight and then titrated, rather than dosed to the total weight. Monitoring of neuromuscular blocking should be used where appropriate, as well as monitoring of the depth of anesthesia. The occurrence of intraoperative recall is indeed more frequent in the obese patient than in the non-obese patient. Appropriate prophylaxis against venous thromboembolic disease and early mobilization are recommended, as thromboembolic disease is increased in the obese patient. The use of non-invasive ventilation to prevent the occurrence of acute post-operative respiratory failure and for its treatment is particularly effective in obese patients. In case of admission to ICU, an individualized ventilatory management based on pathophysiology and careful monitoring should be initiated.

There are many mechanisms for improving the clinical and blood gas status of patients with the obesity hypoventilation syndrome (OHS) or chronic obstructive pulmonary disease (COPD) by non-invasive ventilation (NIV) at home. Our objective was to set up a pilot study to evaluate the potential modification of the sensitivity of the respiratory centers to COWe assessed the sensitivity of the respiratory centers to COAll the patients included had altered ventilatory responses to COThis work showed significant changes in the ventilatory response to hypercapnia in patients with either OHS or COPD after NIV therapy. The significance of these changes deserves to be studied.

As a result of the constantly increasing epidemic of obesity, it has become a common problem in the intensive care unit. Morbid obesity has numerous consequences for the respiratory system. It affects both respiratory mechanics and pulmonary gas exchange, and dramatically impacts on the patient's management and outcome. With the potential for causing devastating respiratory complications, the particular anatomical and physiological characteristics of the respiratory system of the morbidly obese subject should be carefully taken into consideration. The present article reviews the management of obese patients in respiratory failure, from noninvasive ventilation to tracheostomy, including postural and technical issues, and explains the physiologically based ventilatory strategy both for NIV and invasive mechanical ventilation up to the weaning from the ventilatory support.

Pediatric obesity may induce multiple complications, including cardiovascular and metabolic problems in adulthood. It may also cause respiratory disorders, which are not usually the first-intention diagnosis by physicians. The aim of this study was to evaluate how investigations had been performed in obese children referred to Timone Pediatric Hospital.A retrospective study of children referred to our department for severe non-syndromic obesity was conducted. The clinical features comprised history, anthropometric parameters, dietary habits, acanthosis nigricans, symptoms of obstructive sleep apnea syndrome (OSAS) as well as the paraclinical endocrine markers, blood gases, and sleep recordings.Of 102 patients (mean age, 10.5±3.3 years; BMI Z-score, 4.52±1.5), 29.4% had OSAS symptoms (n=30). Nine had a pathological polysomnography confirming OSAS. Eight of them required ventilation: these children were the most severe with an earlier weight gain (2.17±1.2 years vs. 4.0±2.2 years; P=0.01) and a higher BMI Z-score (7.2±2.3 vs. 4.3±1.1; P=0.027). Obesity hypoventilation syndrome (OHS) was diagnosed in 3.9% of these children (n=4).Diagnosis of OSAS and OHS, often overlooked in obese children, requires a systematic approach and early clinical detection of respiratory disorders. Better accessibility to sleep respiratory explorations would improve quality of care for these children.

Noninvasive ventilation is recommended to correct the nocturnal hypoventilation and relieve the symptoms of patients with the obesity-hypoventilation syndrome (OHS). The benefits of fixed pressure ventilation (S/T technology) are recognized but limited on account of the variability of nocturnal ventilatory requirements. The new technique AVAPS-AE (automatic EPAP) allows adjustment of the pressure according to the volume currently targeted. Its efficacy has not yet been evaluated. Our objectives are to evaluate firstly, whether AVAPS-AE optimizes the benefits of S/T technology on sleep architecture and quality, secondly, whether these benefits are associated with an improvement in gas exchange, symptoms, exercise tolerance, level of physical activity and quality of life of patients with OHS. In this multicenter trial, 60 newly diagnosed patients with OHS will be randomized to the control (S/T) and trial (AVAPS-AE) groups. A standardized titration procedure will be followed for the calibration of the ventilators. Functional evaluations (polysomnography, blood gases, impedance measurements and walking tests), questionnaires (physical activity, quality of life, quality of sleep and daytime somnolence) visual scales (fatigue, headaches) and a recording of activity will be undertaken after two months of ventilation.

Severe obesity sometimes leads to a chronic alveolar hypoventilation: obesity hypoventilation syndrome (OHS), (Pao270mmHG, Paco245mmHG and body mass index (BMI)30Kg/m2). The association with an OSAS is frequent.To assess predicting factors that lead to hypoventilation in a population of obese patients with SAS and to deduct the type of association between OHS and SAS.We have study during 4 years, at pneumology service of Charles Nicolle hospital, 62 obese patients (BMI30Kg /m2), 41men and 21 women and presenting an OSAS. We excluded those carriers of a bronchial obstruction (VEMS/CV60%) and we have compared anthropométriques, functional, gazométriques and polysomographiques details of the groupe1 (G1): OHS=9 and of the groupe2 (G2): obesity without hypoventilation (n=53).We didn't identified any significant difference between the two groups concerning (age, sex, the frequency of smokers, the frequency of the nasopharynx region abnormalities, apnea-hypopnea index (AHI), the SAS severity and the respiratory functional exploration). The obesity is significant more important in the G1, it is sever (BMI40) in 77.8% of patients of the G1 with significant difference with the G2 (P=0.004). We noted that there is a positive interrelationship between BMI and Paco2. We identified severe gazométrique perturbation in G1 (Pao2 medium = 61± 9 mmHg,Paco2 medium=50 ± 7 mmHg), in the G2 we noted a moderate hypoxemia. Patients of the group1 make of the minimal desaturation of 63 ± 17% and a Sao2 average of 81 ± 20% what is meaningfully more important than in the G2.The alveolar hypoventilation in SAS seems to be in correlation with the degree of obesity. The hypercapnie in the OHS is in relation neither with the SAOS nor with its severity. The OHSSAS association is usual but not synonym; the OHS is an autonomous disease.

Obesity, well-known as a cardiovascular risk factor is also a "respiratory" risk factor and can have profound adverse effects on the respiratory system, such as alterations in pulmonary function tests, respiratory mechanics, respiratory muscle strength and endurance, gas exchange, control of breathing and exercise capacity. ABG are frequently altered in obese subjects and abnormalities are directly proportional to BMI. Two main pathophysiological mechanisms may account for gas exchange abnormalities: V/Q inequality, responsible for isolated hypoxemia, and alveolar hypoventilation responsible for the also called "obesity hypoventilation syndrome" (OHS). Hypoventilation in obese patients includes a diversity of mechanisms frequently imbricated, among which the two most frequent are mechanical limitation and blunted ventilatory drive. Two other clinical entities (COPD and OSA) frequently present in the obese patients may potentiate or aggravate this hypoventilation. OHS is frequently underappreciated and diagnosis is rarely made at the steady state. Such diagnosis is frequently made in two situations: either during an exacerbation or when in front of symptoms of respiratory sleep disturbances. The patient is referred to sleep laboratory for screening for OSA. Ventilatory management of these patients will depend on the patient's underlying condition and on sleep study results. It includes CPAP or NIPPV but frequently additional O(2) addition is necessary. OHS represents today one of the most frequent indications of NIV worldwide.

The prevalence of obesity has considerably increased during the past thirty years. Possible consequences of obesity on respiratory physiology include a restrictive disorder, changes in ventilatory mechanics and an alteration of respiratory drive. Apart from the well established relation between obesity and obstructive sleep apnea-hypopnea syndrome, obesity is associated with two other respiratory disorders. On one hand, epidemiological and animal data suggest a causal relationship between obesity and asthma. On the other hand, morbid obesity is associated, through an alteration of the respiratory drive involving leptin, with a diurnal and nocturnal alveolar hypoventilation defining the obesity-hypoventilation syndrome. These data emphasize the necessity for the medical practitioner to investigate any respiratory symptomatology in obese patients.

Home mechanical ventilation (HMV) is the treatment of choice for patients with chronic hypercapnic respiratory failure. Since the middle of the 1980's, the number of cases under HMV has markedly increased. Presently, at our centre (n=176 patients), obesity-hypoventilation syndrome (36%), and COPD (21%) are the most frequent indications for HMV. Classical indications such as sequellae of tuberculosis, or poliomyelitis, kyphoscoliosis, or neuro-muscular diseases, represent 25% only of our HMV population. Bi-level pressure support ventilators have replaced the volumetric ventilators used in the 80's in most situations. A specialized team of nurses monitors closely at home clinical evolution, and compliance, gathering an important amount of clinical data, and allowing the early detection of clinical deterioration.

The main indication of LTO is COPD with chronic respiratory failure, where it improves life expectancy. By extension, LTO may be proposed to other etiologies of CRF with chronic documented hypoxemia. Daily duration is at least 15H per day. Non invasive ventilation (NIV) represents facial or nasal ventilation. Consensus indications of NIV are restrictive pulmonary diseases (chest wall and /or parenchmal sequelae, neuromuscular diseases, or obesity hypoventilation syndrome) Real role of NIV in log-term management of COPD remains controversial.

Chronic alveolar hypoventilation is considered as a pejorative factor of several respiratory diseases outcomes. However, its pathophysiological impact has not been studied in a convincing way. This thesis aimed to assess moderate alveolar hypoventilation consequences during restrictive chronic respiratory failure and the effects of its treatment by non-invasive ventilation (NIV). We have shown that Obesity Hypoventilation Syndrome patients (OHS) had more severely impaired endothelial function and higher systemic low-grade inflammation than simple obese patients. Arterial PaCO2 was correlated with endothelial dysfunction (Borel et al, manuscript in preparation). We have also reported that in OHS, the proportion of REM-sleep time spent in hypoventilation was related to lowered CO2 ventilatory response and to excessive diurnal sleepiness. Non-invasive ventilation improved objective diurnal vigilance (Chouri-Pontarollo et al Chest 2007). Currently, we are conducting the first randomized NIV versus observation during one month study in OHS. The intermediate analysis showed that one month of nocturnal NIV led to a diurnal PaCO2, an improvement of sleep structure and an increase of total lung capacity. However, neither cardiovascular nor metabolic parameters were modified. When NIV was used during exercise, in patients with chronic thoracic restrictive respiratory failure, minute ventilation and exercise tolerance were improved (Borel et al, Resp Med 2008). In these patients, long term training with NIV had no additional benefits as to training in spontaneous breathing, except for the most severe of them. For those later patients, training with NIV lead to a larger improvement in six minutes walking distance and in quality of live, particularly in their fatigue. We also focused on the impact of intentional leak levels of different masks on the performance of ventilators designed for bi-level positive pressure ventilation. Increase of intentional leaks significantly impaired the capacity of ventilators to attain and maintain preset inspiratory pressure and could decrease tidal volume. These significant effects occurred mainly for intentional leaks above 40 l/min (for an inspiratory pressure of 14 cmH2O) (Borel et al, Chest 2008 in press). Conclusion: Chronic alveolar hypoventilation may be considered as one of the patho-physiological factors of endothelial dysfunction, inflammation, sleepiness and exercise intolerance. In spite of technological limitations of bi-level pressure machines currently used, nocturnal NIV corrects alveolar hypoventilation in OHS patients; however its short term and long term impacts on inflammation and endothelial dysfunction remain uncertain. During respiratory rehabilitation program, using NIV during exercise improves exercise capacities and quality of life for the most severe restrictive respiratory failure patients., L'hypoventilation alvéolaire chronique est considérée comme un marqueur d'évolution péjorative de différentes pathologies respiratoires. Cependant, son rôle physiopathologique dans différentes dysfonctions systémiques n'a pas été étudié de manière convaincante. Cette thèse avait pour but d'investiguer les conséquences de l'hypoventilation alvéolaire modérée au cours de l'insuffisance respiratoire chronique restrictive et les effets de son traitement par ventilation non-invasive. Nous avons montré que des patients affectés d'un syndrome obésité-hypoventilation (SOH) avaient une fonction endothéliale plus sévèrement altérée et une inflammation systémique plus importante que les patients obèses simples. La PaCO2 était corrélée à la dysfonction endothéliale (Borel et coll, manuscrit en préparation). Nous avons observé que la proportion d'hypoventilation en sommeil paradoxal, chez les sujets SOH, était associée à une réponse ventilatoire au CO2 abaissée et une somnolence diurne excessive. Pour la première fois, nous avons constaté que la ventilation non invasive nocturne améliorait la vigilance diurne objective (Chouri-Pontarollo et coll, Chest 2007). Nous menons actuellement la première étude randomisée du traitement des patients porteurs d'un SOH par VNI versus observation pendant un mois. L'analyse intermédiaire montrait qu'un mois de VNI nocturne chez les patients SOH améliorait la PaCO2 diurne, la capacité pulmonaire totale, la structure du sommeil, cependant aucun paramètre cardiovasculaire et métabolique n'était modifié. Chez des patients insuffisants respiratoires chroniques pariéto-restrictifs, la VNI utilisée au cours d'un exercice aigu, augmentait la ventilation et améliorait la tolérance à l'effort (Borel et coll, Resp Med 2008). Chez ces mêmes patients, un réentrainement à l'effort sous VNI n'apportait pas de bénéfices additionnels par rapport à un réentrainement en ventilation spontanée sauf chez les patients les plus sévères. Ces derniers, amélioraient leur périmètre de marche et leur qualité de vie. Leur fatigue en particulier était améliorée s'ils s'étaient réentraînés sous VNI (Borel et coll, Am Journal of physical med and rehab, 2008, soumis). Enfin, nous avons analysé l'impact des fuites intentionnelles des masques de VNI sur la performance des appareils de VNI bi-pressionnels. L'augmentation des fuites intentionnelles diminuait les capacités des appareils à atteindre et maintenir la pression de consigne. Ceci pouvait conduire à une diminution du volume délivré au patient, en particulier pour des fuites intentionnelles supérieures à 40 L.min-1 à 14 cm H2O de pression (Borel et al, Chest, sous presse). Conclusion : L'hypoventilation alvéolaire chronique peut-être considéré comme un déterminant physiopathologique de la dysfonction endothéliale, de l'inflammation, de la somnolence, et de l'intolérance à l'effort. La VNI, utilisée au cours des efforts, permet d'améliorer les capacités d'exercice et la qualité de vie des patients insuffisants respiratoires restrictifs les plus sévères. Malgré les limites technologiques des appareils de VNI bi-pressionnels utilisés actuellement, la VNI corrige l'hypoventilation alvéolaire des patients SOH, cependant les effets sur l'inflammation, la dysfonction endothéliale restent incertains à cours et long terme chez ces sujets obèses.

A classical definition of Pickwickian syndrome associates alveolar hypoventilation, obesity and hypersomnia with periodic breathing. Obesity in itself is enough to explain the alveolar hypoventilation and some of the sleep disorders, but in fact all three elements of this syndrome are intricated. Obesity, whether associated with a Pickwickian syndrome or not, affects ventilatory mechanics similarly. With the cause of sleep disorders are associated central ventilatory pauses, appearing periodically followed by phases of apnoea secondary to buccopharyngial hypotony. The alveolar hypoventilation is therefore the consequence of obesity and periodic apnoea. It also results from a low respiratory frequency considering that the tidal volume is also decreased. These different elements suggest some disorder of the centers controling ventilation. One can describe different nosological forms, all having as a common factor hypersomnia with periodic respiration, the latter being a determining factor in the diagnosis. Therapy, including weight reduction and symptomatic treatment of alveolar hypoventilation, is now augmented by new drugs acting on the central nervous system.

Results of several surveys of variable complexity have provided confirmation that snoring is not only an overall sleep preventer but is mainly an unrecognized asphyxia. Comparison of groups of snorers and non-snorers, and evaluation of biologic and functional improvement following surgical treatment of snoring, have shown that this chronic nocturnal hypoxia is, with the snoring as such, the essential feature of a well individualized new disease for which the term chronic rhonchopathy is proposed. This affection is composed of different clinical aspects of several syndromes, notably the Pickwickian and sleep apnea syndromes. However, a latent form also exists in which snoring is the only symptom, as well as a decompensated form with multiple signs related to the underlying condition. Improvement follows suppression of the respiratory obstacle provoking snoring. The most frequent of these signs is drowsiness, particularly when driving, and is the one with the heaviest social consequences.

The writers analyze 29 nyctohemeral recordings in 20 patients with sleep apneas. In addition to the standard polygraphy, use is made of pneumotachography and capnography. The results (central apnea with open or secondarily closed glottis; obstructive apnea with closed glottis or with expiratory valve phenomenon) raise the hypothesis of a central physiopathological mechanism common to the various types of apneas through a more or less dissociated inhibition of the activity of the respiratory, laryngeal, intercostal, and diaphragmatic muscles:--in central apnea: inhibition of the thoracoabdominal activity and maintenance of the tonicity of the laryngeal muscles, keeping the glottis open;--in obstructive apnea: persistence of the thoracic and/or abdominal activity with inhibition of the activity of the laryngeal muscles, leading to a passive obstruction due to the effect of inspiratory depression.

The authors studied a series of 10 obese patients with respiratory failure referred for treatment because of sleep disorders and diurnal, sometimes uncontrollable, episodes of somnolence. 8 parameters were recorded in the polygraphic study performed during a night of hospitalization: electroencephalogram, electrocardiogram, electro-oculogram, chin electromyogram, thoracic movements, and nasal and buccal air flows. SaO2 and transcutaneous PO2 were recorded simultaneously. A sleep apnea syndrome was diagnosed in 6 of the 10 patients, whose apnea index was markedly above the limit of 5 apneas per hour. The apnea index was below 5 in the other 4 patients. Most patients with sleep apnea syndrome suffer from obstructive apneas of varying duration taking up as much as 48% of total sleep time. The cardiorespiratory effects of these events are apparent, with a drop in PO2 and SaO2 and a decrease in heart rate at the end of apnea. Polygraphic studies seem useful in the diagnosis of the pickwickian syndrome. They allow the type of apnea and its effects to be specified and thus guide treatment.

After a short recall of the Pickwick's disease. Authors study the obstructive Apnea phenomenon of the disease. Electromyographic record shows the disappearance of the muscular activity which is necessary to let open the aerian track. Tracheotomy avoid apnea without healing the disease.