It all makes sense to me, except for the part that says "the maximum pressure due to a closed airway apnea is 12 cm H2O. The therapy pressure still increases above 12 cm H2O if it is driven by either continued snoring or flow limitation. So the algorithm just ignores any apneas that happen after the pressure increases to 12 cm? Does this mean that the "For Her" algorithm wouldn't be a good fit for someone whose pressures typically go above 12 cm?
Summary of AutoSet for Her therapy features and their relevance to female-associated OSA (adapted from Table 1 of article)
Female-associated OSA characteristics AutoSet for Her Therapy Feature
1. Women experience shorter obstructive events - Device includes RERA reporting to indicate the occurrence of respiratory events not strictly meeting the definition of an apnea or hypopnea.
2. Women are prone to more upper airway resistance and flow limitation - A single breath index is used to calculate and respond to the patient’s flow limitation (3 breath average used in standard AutoSet).
3. Women have predominantly REM-based events - If 2 apneas are detected within a minute, an ‘adaptive minimum pressure’ prevents therapy pressure decaying below this level for the remainder of the session. Minimum pressure will not exceed 10cmH2O.
4. Women require lower CPAP pressures than
males - The maximum pressure due to a closed airway apnea is 12 cm H2O. The therapy pressure still increases above 12 cm H2O if it is driven by either continued snoring or flow limitation. This reduces the likelihood of reaching high pressures over short periods.
5. Women may experience more arousals from sleep - The algorithm contains several modifications to the internal gains of the algorithm which effectively result in a slower (and lower) pressure rise and decay when compared to standard AutoSet.
from Obstructive Sleep Apnea in Women: Specific Issues and Interventions
AJ Wimms, MSc Med; S Ketheeswaran, BBiomedSc; JP Armitstead, PhD
ResMed Science Center, Sydney, Australia