Clinical Impact of Patient-ventilator Asynchrony

Inclusion Criteria : * Women and Men aged of at least 18 years old. * NIV equipment since 6 months ( at least) * Chronic respiratory failure requiring NIV equipment defined by clinical symptoms (asthenia, excessive daytime sleepiness, headache, dyspnea) and: In case of obstructive diseases : Daytime hypercapnia (PaCO2 \> 55 mmHg) or Daytime hypercapnia between 50-54 mmHg associated with nocturnal desaturations (at least 5 min below 88% saturation) or episodes of frequent hypercapnic exacerbations (at least 2 over the last 12 months) In case of restrictive diseases : Daytime hypercapnia (PaCO2\>6 kPa (kilopascal) or 45 mm Hg) or Nocturnal desaturation (SaO2 \< 88%) for at least 5 minutes without obstructive sleep apnea syndrome (OSAS) found or Marker of progression of neuromuscular damage (Maximum inspiratory pressure \< 60 cm H2O and forced vital capacity (FVC) less than 50% of theory) * NIV's start from at least 6 months. * Patient who did not object to being included in the study. * Patient in stable condition without exacerbation (for at least 3 months) Exclusion Criteria : * Minor patient * Pregnant or breastfeeding women * Adult patient subject to enhanced protection, deprived of liberty by judicial or administrative decision. * Patient who is physically or psychologically unable to follow the protocol in an informed manner. * Patient with chronic respiratory failure requiring mechanical ventilation by tracheotomy * Patient having changed center or service provid…