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

Study Overview
=================
Brief Summary
-----------------
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.

Detailed Description
-----------------
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.

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

Conditions
-----------------
Obesity, Non Invasive Ventilation

Intervention / Treatment
-----------------
* Device: Adjustment of back-up respiratory rate on bi-level ventilator


Participation Criteria
=================
Eligibility Criteria
-----------------
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.

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 75 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Supportive Care
Intervention Model: Single Group Assignment
Masking: Single


Arms and Interventions

| Intervention/Treatment |
| --- |
|Device: Adjustment of back-up respiratory rate on bi-level ventilator|3 consecutive nights in randomized order, in either S (Spontaneous) mode, ST (Spontaneous/Timed) mode with a back-up rate under spontaneous respiratory rate of the patient, or in ST (Spontaneous/Timed) mode with a back-up rate at least 2 cycles/minute above spontaneous nocturnal respiratory rate. Each assessment will include complete polysomnographic recording (sleep study) as well as SpO2, PtcCO2, pneumotachograph (flow), mask pressure, quantitative assessment of patient-ventilator synchronisation, central or obstructive apnea and hypopnea, data of built-in software, and rating of patient comfort|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sleep structure | Quantification of quality of sleep assessed by polysomnography (sleep stages, arousals) | Night 1 | 
| Sleep structure | Quantification of quality of sleep assessed by polysomnography (sleep stages, arousals) | Night 2 | 
| Sleep structure | Quantification of quality of sleep assessed by polysomnography (sleep stages, arousals) | Night 3 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Transcutaneous capnography (PtcCO2) | Mean PtcCO2 during Night 1 | Night 1 | 
| Transcutaneous capnography (PtcCO2) | Mean PtcCO2 during night 2 | Night 2 | 
| Transcutaneous capnography (PtcCO2) | Mean PtcCO2 during night 3 | Night 3 | 
| Correlation between microarousal index and autonomic arousal index | Correlation between microarousal index (assessed by EEG) and autonomic arousal index under NIV (assessed by pulse plethysmography) | Night 1 | 
| Correlation between microarousal index and autonomic arousal index | Correlation between microarousal index (measured by EEG) and autonomic arousal index (measured by pulse plethysmography) | Night 2 | 
| Correlation between microarousal index and autonomic arousal index | Correlation between microarousal index (measured by EEG) and autonomic arousal index (measured by pulse plethysmography) | Night 3 |