Physiological Study to Compare Noninvasive Ventilation (NIV) Masks

Physiological Study to Compare Noninvasive Ventilation (NIV) Masks

Noninvasive ventilation (NIV) is an established therapy that delivers positive pressure to the upper airways to provide respiratory support. Two types of NIV can be delivered; continuous positive airway pressure (CPAP) at one continuous pressure and bilevel NIV at two pressures for inhalation and exhalation.

This investigation is designed to physiologically evaluate the performance of a NIV mask, Mask A, compared to a standard NIV mask, Mask B on CPAP therapy.

People with sleep disordered breathing who have chronic hypercapnia, and are already receiving nocturnal CPAP will be recruited. They will receive one night's CPAP therapy on Mask A and 1 night on Mask B in random order. Physiological parameters will be recorded.

Parameters will be recorded during three baselines at the beginning of each evening and throughout the night when participants are asleep. The three baselines are:

1. participant awake with normal breathing (not on CPAP),
2. participant awake and on CPAP, and
3. participant asleep on CPAP in REM-sleep (rapid eye movement sleep).

Inclusion Criteria:

• Already using overnight CPAP and tolerating the therapy well (over 4 hours use/night)
• Hypercapnia: venous bicarbonate of 30 milliequivalents of solute per liter (Eq/L) or more, OR transcutaneous carbon dioxide (TcCO2) of 50 millimeters of mercury (mmHg) of more.
• Provide written informed consent
• Already use a full (oronasal) face mask for CPAP
• Willing to have a venous blood sample taken during the pre-screening visit.

Exclusion Criteria:

• Presence of sleep apnea on CPAP:

  • Subjects excluded if they have an apnea-hypopnea index (AHI) of more than 20, or
  • If the AHI has not already decreased by 50 percent or more from pre-CPAP to with CPAP.

• Forced expiratory volume in 1 second (FEV1) of less than 40 percent of predicted.

• Forced expiratory volume in 1 second divided by forced vital capacity (FEV1/FVC) less than fifty percent of predicted, at the screening visit.

  • Have poorly controlled asthma or changing asthma symptoms.
  • Nasal obstruction
  • Do not fit Mask A or Mask B
  • Agitation or psychological illness