Patient-ventilator Interactions in Long Term Non-invasive Ventilation: Influence of Back-up Frequency

Patient-ventilator Interactions in Long Term Non-invasive Ventilation (NIV): Influence of Back-up Frequency

In patients under bi-level pressure support ventilation for obesity hypoventilation syndrome, this study aims to determine if it is better, in terms of efficacy and patient-ventilator synchronisation to use

• Spontaneous mode (S)
• Spontaneous/Timed mode (ST) with an intermediate back-up rate, slightly below the respiratory rate of the patient
• Timed mode (T), with a ventilator respiratory rate above that of the patient. This issue has to our knowledge only been marginally studied without any consensus.

Eligibility: patients under home bi-level pressure support ventilation for obesity hypoventilation in a stable clinical condition, aged over 18

Methods:

Three consecutive sleep studies in a randomised sequence with usual parameters Inspiratory Positive Airway Pressure(IPAP), Expiratory Positive Airway Pressure (EPAP) and change of only back up respiratory rate (RR): one night in a spontaneous mode, one with an intermediate RR, and one with a RR above that of the patient

Endpoints:

Quality of sleep and sleep structure (polysomnography), patient-ventilator synchronisation and respiratory events under NIV, efficacy of ventilation: oxygen saturation measured by pulse oxymetry (SaO2); transcutaneous capnography (PtcCO2), and comfort.

Inclusion Criteria:

• Obesity-hypoventilation (OHS) patients, in stable clinical condition, treated with domiciliary nocturnal non invasive ventilation for at least two months

Exclusion Criteria:

• OHS patients: unstable cardio-respiratory status and/or acute cardio-respiratory failure three months before inclusion.