Prevalence of Nocturnal Hypoventilation in Obese Subjects Fiited With Continuous Positive Airway Pressure for Obstructive Sleep Apnea / Hypopnea Syndrome (CAPNOSOH)

Toulouse University Hospital

Status: Not yet enrolling

Conditions: Sleep Apnea Hypopnea Syndrome; Obesity; Nocturnal Hypoventilation

Treatments: Other: Body plethysmography; Other: Quality of life questionnaires; Other: Arterial gasometry; Other: Transcutaneous Oxy-Capnography; Other: Spirometry with reversibility test; Other: Clinical examination

Study type: Interventional

Funder types: Other

Identifiers

NCT07152990

2025-A00694-45 (Other Identifier)

RC31/24/0290

Details and patient eligibility

About

CAPNOSOH study is a single-center study conducted at Toulouse University Hospital, aiming to estimate the prevalence of obese and apneic subjects maintaining nocturnal hypoventilation under continuous positive airway pressure (CPAP).

Full description

Obstructive sleep apnea hypopnea syndrome (OSAS) is highly prevalent in the global population (1 in 10 people worldwide according to Inserm), particularly in relation to the increase in the prevalence of obesity. The standard treatment for this pathology is continuous positive airway pressure (CPAP) which most often allows, when properly applied and adjusted, the normalization of symptoms and the apnea-hypopnea index (AHI). In addition to OSAHS, some obese subjects are at risk of presenting hypoventilation obesity syndrome (OHS) defined by the presence of obesity (body mass index [BMI] > 30 kg/m2) associated with diurnal hypoventilation. (PaCO2 > 45 mmHg) in the absence of other respiratory pathology. Identifying patients with OS is often difficult but essential, as early as possible.

Transcutaneous capnography, when properly performed and interpreted, is a much more informative tool than nocturnal oximetry, and could therefore allow better screening for these patients. It is an examination increasingly used in pulmonology departments/sleep centers.

The CAPNOSOH study is a single-center study conducted at Toulouse University Hospital, aiming to estimate the prevalence of obese and apneic subjects maintaining nocturnal hypoventilation under continuous positive airway pressure (CPAP). The study hypothesis is based on the limited data present in the literature. This is preliminary work for a multicenter study aimed at determining the impact of nocturnal hypoventilation without daytime hypercapnia on the quality of life and morbidity and mortality of patients.

We estimate that between 10 to 20% of obese subjects on CPAP hypoventilate at night.

Enrollment: 139 estimated patients

Sex: All

Ages: 18 to 80 years old

Volunteers: No Healthy Volunteers

Inclusion and exclusion criteria

Inclusion criteria:

• Obese patients (Body Mass Index > 30 kg/m2)
• Fitted by one of the following providers: ASTEN, Vitalaire, Orkyn, ISIS, RespiO2, BASTIDE for > 3 months with compliance of more than 4 consecutive hours per night in average during 3 months
• "Good quality" criteria for continuous positive airway pressure (CPAP) treatment: compliance > 4 consecutive hours per night, unintentional leaks < limit defined by the manufacturer, residual AHI < 10/h
• Aged 18 to 80
• Affiliated or beneficiaries of the social security system or equivalent
• Having given written informed consent
• Able to understand instructions and information given

Exclusion criteria :

• Patient under legal protection measure
• Non-compliant patients
• Pregnant or breast-feeding women (assessed on questioning)

Trial design

Primary purpose: Diagnostic

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

---

139 participants in 1 patient group

Obese Patients with Obstructive Sleep Apnea/Hypopnea

Other group

Treatment:

Other: Clinical examination

Other: Spirometry with reversibility test

Other: Transcutaneous Oxy-Capnography

Other: Arterial gasometry

Other: Quality of life questionnaires

Other: Body plethysmography