Efficacy of Average Volume Assured Pressure Support With Bi-Level Pressure Support Nocturnal Ventilation
Condition: Chronic Hypercapnic Respiratory Failure; Obesity Hypoventilation Syndrome; Chronic Obstructive Pulmonary Disease
MeSH terms: Lung Diseases, Obstructive; Pulmonary Disease, Chronic Obstructive; Respiratory Insufficiency; Hypoventilation; Obesity Hypoventilation Syndrome
Study type: Interventional

Summary: 
      Patients with chronic hypercapnic respiratory failure can be successfully treated with home
      nocturnal non-invasive ventilation. Bi-level pressure support ventilators are at present the
      most frequently used ventilators for long term home ventilation. A recently commercialized
      bi-level ventilator offers the feature of automatically adjusting pressure support on the
      basis of a pre-determined ideal effective ventilation. Because this option may induce
      important swings in pressure support, and thus patient discomfort, and maybe increase leaks,
      we chose to analyse the impact of average volume assured pressure support (AVAPS) on patient
      comfort, subjective and objective quality of sleep and efficacy of ventilatory support.
    

Detailed description: 
      This study aims to compare, in a randomized order, two consecutive nights with a bi-level
      positive pressure ventilator (Synchrony, Respironics, USA), with and without average volume
      assured pressure support (AVAPS), in patients with chronic respiratory failure, treated on a
      long term basis by home nocturnal non-invasive ventilation.

      Specific endpoints are :

        -  quality of sleep assessed by polysomnography scored by an independent investigator
           (sleep efficiency, distribution of sleep stages, arousals and sleep stage changes) and
           subjective scores (St Mary's questionnaire),

        -  perception of comfort of ventilation (clinical score),

        -  efficacy of ventilation (pulsoximetry, transcutaneous capnography (Tina TCM4 Radiometer,
           Copenhagen), effective ventilation and tidal volumes, leaks as measured by ventilator,
           Stardust software, Respironics).

      Patients: Fourteen patients with obesity-hypoventilation and/or COPD, treated and stable for
      at least 3 months, will be included and undergo complete sleep studies in Geneva University
      Hospital's Sleep Laboratory. Patients included must be compliant to treatment (at least 4
      hours of use of ventilator/night).

      Methods: Patients are blinded as to whether or not AVAPS is implemented. Target tidal volume
      is set at 7-8 ml/kg. EPAP (Expiratory positive airway pressure) level is unchanged. Minimal
      IPAP (Inspiratory positive airway pressure) level is set at usual IPAP - 3 cm H2O. Maximal
      IPAP is set between 25 and 30 cm H2O. Back up frequency is unchanged.

      All patients must provide written informed consent. Protocol has been accepted by the ethics
      committee on clinical research of Geneva University Hospital.

      Results of scores, and relevant parameters of polysomnography, oxymetry, and capnography,
      will be compared.
    

Intervention name(s): Average volume assured pressure support (AVAPS)
Intervention type(s): Procedure
Allocation: Non-Randomized
Intervention model: Crossover Assignment
Masking: Single
Primary purpose: Supportive Care
Keywords: Non-invasive ventilation; Polysomnography; Average volume assured pressure support