Sleep Disorders |

Flex-Settings Increase Central Apneas And Reduce Mask Leak but Have No Effect on Overall Compliance FREE TO VIEW

Geoffrey Loh; Karen Shiekh; Jordanna Hostler; Andrei Khramtsov; Brian Foster; Amy Puderbaugh; Aaron Holley
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Walter Reed National Military Medical Center, Bethesda, MD

Chest. 2014;146(4_MeetingAbstracts):954A. doi:10.1378/chest.1995089
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SESSION TYPE: Original Investigation Poster

PRESENTED ON: Wednesday, October 29, 2014 at 01:30 PM - 02:30 PM

PURPOSE: Previous studies have shown that a continuous flexible (C-flex) pressure setting added to auto-adjustable positive airway pressure (auto-PAP) can improve compliance but the effects of auto-flex (A-flex) are less clear. In a large group of patients we sought to determine whether adding A-flex to auto-PAP would improve compliance, apnea-hypopnea index (AHI) and central apnea index (CAI).

METHODS: Patients were randomly assigned to have either an auto-flex setting of 2 or no flex added to their initial auto-PAP prescription. They were prospectively followed for 4 weeks to determine the effects that the flex setting has on compliance, apnea-hypopnea index (AHI), leak and central apnea index (CAI).

RESULTS: There were 67 patients who had A-flex with auto-PAP and 56 patients with auto-PAP alone. At baseline there was no difference in AHI (15.2±8.8 vs 16.5±12.3, p=0.52) between groups. There was no difference in percentage of nights PAP used (86.1±21.6 vs 87.4±16.8, p=0.43) or in percentage of nights PAP used greater than four hours (72.1±29.2 vs 72.9±22.3, p=0.70) at four weeks. Despite there being no difference in minimum or maximum pressures prescribed patients on A-flex had a decrease in large leak (1 (IQR: 0-5) vs 2 (IQR: 0-14) liters/minute (LPM), p=0.05). There was also no difference in CAI on PSG but there was an increase in CAI (2 (IQR: 0-8) vs 1 (IQR: 0-2), p=0.001) at four weeks.

CONCLUSIONS: The addition of A-Flex to standard auto-PAP does not improve compliance but does reduce large leak. The A-flex setting also increases the CAI at follow-up, possibly due to augmentation of ventilation.

CLINICAL IMPLICATIONS: A-flex does not improve compliance. Patients with significant amounts of mask leak may benefit from using the A-flex setting while those with an elevated CAI may benefit from having it turned off.

DISCLOSURE: The following authors have nothing to disclose: Geoffrey Loh, Karen Shiekh, Jordanna Hostler, Andrei Khramtsov, Brian Foster, Amy Puderbaugh, Aaron Holley

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