AutoSet for Her

Split out to a separate article later

ResMed Corporation has recently developed a female-specific AutoSet for Her (AfH) algorithm; designed to optimize the pressure response to the specific patterns of obstructive sleep disordered breathing seen in women. The AfH algorithm is adapted from the S9 AutoSet algorithm (ResMed Ltd., Bella Vista, Sydney) with a number of modifications, including

an increased sensitivity to flow limitation,
- The AfH algorithm has been designed to be more sensitive to flow limitation by responding to the first identified flow-limited breath rather than requiring three consecutive flow-limited breaths, as occurs with the standard AutoSet algorithm.
an optimized internal gain (a slower, and lower, pressure rise and decay in response to flow limitation),
- the AfH algorithm increases pressure in response to flow limitation at a slower rate and to a lesser extent than the standard AutoSet algorithm (similarly the decay in the gain is lower).
a lower cap on the pressure response to obstructive apneas,
- In order to prevent an excessive pressure rise, the AfH algorithm does not increase pressure above 12 cm H2O in response to detected apneas (but pressure can increase above 12 cm H2O if other respiratory events are present).
an adaptive minimum pressure
- Another novel feature of the AfH algorithm is a moving minimum AutoSet pressure (i.e., a minimum pressure is set to which pressure decreases during sleep periods devoid of respiratory events). If apneas occur within a short time period the minimum AfH pressure will automatically increase and the pressure will not decline below this level for the remainder of the night’s therapy. The purpose of this is to minimize inappropriate pressure decreases during REM sleep that could occur with the standard AutoSet algorithm.

Conclusion: Among premenopausal women a novel female-specific autotitrating algorithm (AfH) is as effective as the standard AutoSet algorithm in controlling obstructive sleep apnea (OSA). The new algorithm may reduce flow limitation more than the standard algorithm and achieve control of OSA at a lower (95th centile) pressure.

Comparison of efficacy outcomes during standard AutoSet vs AutoSet for Her (AfH) treatment nights.