BACKGROUND: Adaptation to noninvasive ventilation (NIV) is a critical step for acceptability and efficacy of this treatment during sleep in patients with chronic respiratory failure.

AIM: To study the variability of patient-ventilator interactions during the first nights after initiation to NIV. Recorded data will be analyzed in part by dedicated tools from the non-linear dynamics theory.

PATIENTS AND METHODS: Patients with chronic respiratory failure at stable state and indicated to home NIV will be included. All patients will perform three polysomnographies (under spontaneous breathing at D1 and under NIV at D2 and D15 after NIV initiation). All ventilatory physiological data (pressure, flow, patient-ventilator interactions, oxygen saturation, non intentional leaks) will be recorded during sleep under NIV in the Sleep Laboratory of the Department and secondarily related to sleep architecture and quality of sleep.

EXPECTED RESULTS: This study will identify objective parameters that are associated to a satisfactory adaptation to nocturnal NIV.

Inclusion Criteria:

• Chronic respiratory failure with indication to domiciliary NIV according to the international guidelines.

Exclusion Criteria:

• Decompensated respiratory failure attested by a pH <7.35,
• Modification of respiratory symptoms during the four previous weeks, including signs of broncho-pulmonary infection,
• Respiratory frequency >30/min.

Patients with chronic respiratory failure at stable state who are indicated to domiciliary noninvasive ventilation