Usefulness of Transcutaneous Capnography to Assess Residual Hypoventilation in Obesity-Hypoventilation Syndrom Treated by Non Invasive Ventilation at Home : a Prospective Study

Study Overview
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Brief Summary
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Transcutaneous capnography (PtcCo2) recently showed good agreement with blood gases to assess hypercapnia. There is no study that has evaluated the benefit to realise systematically a nocturnal PtcCo2 in the follow-up of home-ventilated patient with obesity hypoventilation syndrome (OHS). The investigators will evaluate the intake bring by nocturnal transcutaneous capnography, compared to nocturnal oximetry and blood gases, to diagnose nocturnal alveolar hypoventilation in a population of patient presenting an OHS, treated by non invasive ventilation (NIV) at home .

Detailed Description
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Patients will be evaluated once a year in consultation with a blood gases, and then a nocturnal recording at home including a transcutaneous capnography and an oximetry. Some data will be registered too : cardiovascular and neurological comorbidities, diabetes mellitus, treatment, parameters of the non-invasive ventilation, duration of compliance and apnea-hypopnea index (if available). The investigators will perform a sequential analysis of nocturnal hypoventilation with first blood gases, then nocturnal oxymetry and to finish nocturnal PtcCo2. It will allow us to determine if PtcCo2 catch up some nocturnal hypoventilation, undetected by the first two exams. The investigators plan that the study will last 18 months. The analysis will be descriptive. Quantitative variables will be described with mean, standard deviation, minimum, maximum and median. Quantitative variables are presented with number and percentage. Comparison of blood gas / oximetry association with blood gas / oximetry / transcutaneous capnography using a McNemar test

Official Title
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Usefulness of Transcutaneous Capnography to Assess Residual Hypoventilation in Obesity-Hypoventilation Syndrom Treated by Non Invasive Ventilation at Home : a Prospective Study

Conditions
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Obesity Hypoventilation Syndrome

Intervention / Treatment
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* Other: No Interventional study


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Obesity Hypoventilation Syndrom defined by a diurnal PaCo2> 45 mmHg, in stable conditions, in a patient presenting an obesity (BMI > 30 kg/m²) treated by non invasive ventilation since at least 3 weeks, and seen in follow-up consultation Exclusion Criteria: minors refusal to participate under guardianship or trusteeship pregnant woman other etiology of hypoventilation : copd, kyphoscoliosis, neuromuscular disorders, diaphragmatic pathology

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Other: No Interventional study|every patient will be monitored with a blood gase, a nocturnal oximetry and a transcutaneous capnography|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| nocturnal hypoventilation | Nocturnal PtcCo2 > 49 mmHg more than 10% of sleeping time | Until 37 days | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Obesity Hypoventilation Syndrome, Non Invasive Ventilation, Transcutaneous capnography