Auto-trilevel Ventilator for Patients With Overlap Syndrome
Condition: Overlap Syndrome
MeSH terms: Undifferentiated Connective Tissue Diseases; Syndrome
Study type: Interventional

Summary: 
      Obstructive Sleep Apnea Syndrome (OSAS) and chronic obstructive pulmonary disease (COPD) are
      two diseases that often coexist and are called overlap syndrome(OS). Compared to single OSAS,
      OS patients are more susceptible to serious hypoxia and hypercapnia especially during sleep,
      and are much more likely to result in pulmonary hypertension and cor-pulmonal.

      With a more flexible expiratory positive airway pressure (EPAP), auto-trilevel ventilation
      may be superior to fixed bilevel positive airway pressure (BiPAP) ventilation in both
      removing residual obstructive sleep apnea hypopnea events and correcting hypercapnia
      simultaneously. The overall purpose of this study is to compare the curative effects between
      fixed BiPAP and auto-trilevel ventilations on OS patients.
    

Detailed description: 
      The contradiction in treatment for overlap syndrome is how to improve hypercapnia because of
      narrower difference between inspiratory positive airway pressure (IPAP) and expiratory
      positive airway pressure (EPAP), and meanwhile to eliminate apnea and popnea events which may
      easily occur at the end of expiration For ordinary Bipap ventilator. If the IPAP is set to
      higher, the patients may feel discomfort, if the pressure difference between IPAP and EPAP is
      too narrow or the expiratory positive airway pressure (EPAP) too high, hypercapnia may occur.
      If the EPAP is too low, redusual apnea and hypopnea event may become common.

      Auto-trilevel ventilation, with a lower airway pressure at the beginning of expiration to
      prevent hypercapnia and a higher airway pressure at the end of expiration to prevent residual
      apnea events, should be able to provide a novel ventilation mode with a higher efficacy and
      lower average airway pressure for overlap syndrome. To prove the hypothesis, comparison is
      made between ordinary BiPAP and auto-Trilevel ventilation modes during treatment for patients
      with overlap syndrome.

      In this study, the investigators compare the changes of related indexes including apnea
      hypopnea index、minimal pulse oxygen saturation、arousal index, sleep quality,PaCO2 and
      sleepiness scores) before and on treatment. Meanwhile, curative effects will be compared
      between BiPAP and auto-Trilevel ventilation modes. The investigators will analyze the changes
      and then confirm our hypothesis.
    

Intervention name(s): BiPAP ventilation, auto-trilevel ventilation
Intervention type(s): Device
Intervention description(s): Noninvasive ventilation including fixed BiPAP ventilation and auto-trilevel ventilation. Using the same IPAP, treatment include one night with BiPAP ventilation mode 1, one night with BiPAP ventilation mode 2 and one night with auto-trilevel ventilation mode. Each treatment last 8 hours for each night.
Other intervention name(s): bi-level postive airway preesure ventilation;; auto-trilevel ventilation
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Obstructive Sleep Apnea hypopnea Syndrome; COPD; overlap syndrome; Auto-trilevel ventilation; BiPAP ventilation