AutoSet nasal CPAP titration: Constancy of pressure, compliance and effectiveness at 8 month follow-up

Abstract

We have previously shown that AutoSet satisfactorily improves sleep disordered breathing and sleep architecture in subjects with obstructive sleep apnoea (OSA) syndrome. The aim of this study was to determine, in subjects treated with long-term conventional fixed pressure continuous positive airway pressure (CPAP) at the AutoSet recommended pressure, whether: the long-term compliance is satisfactory; the improvement persists once initial rebound is over; the titration pressure is stable with time; and the titration pressure is comparable with manual titration pressure using a similar end-point. Twenty males with OSA, previously studied with full polysomnography on their diagnostic night, at manual and AutoSet titration, and at the AutoSet recommended fixed pressure, were re-studied after a mean of 3 and 8 months of treatment at the recommended fixed pressure. Re-study included home respiratory monitoring (Nellcor EdenTrace(TM)), and repeated manual and AutoSet titration with polysomnography. Compliance was assessed with hour-meter readings. Mean (±SEM) usage was 5.7 ± 0.1 h · night-1 at 3 and 8 months. The arousal index remained normalized. Diagnostic respiratory disturbance index (RDI) was 60.3 ± 5.7 events · h-1. On AutoSet at fixed CPAP, RDI was initially 2.6 ± 0.7 events · h-1, then rose slightly (p < 0.001) to 4.3 ± 0.6 events · h-1 at 3 months, and was 3.6 ± 0.5 events · h-1 at 8 months. AutoSet titration pressure was: 9.9 ± 0.4 cmH2O initially, 10.6 ± 0.4 cmH2O at 3 months, and 9.7 ± 0.5 cmH2O at 8 months (NS). Manual titration pressure at 8 months was 10.4 ± 0.4 cmH2O. The standard deviation of the discrepancy with AutoSet was 0.84 cmH2O. In conclusion, the AutoSet recommended pressure varies little with time, and closely predicts the final manual titration pressure; the improvement in respiratory disturbance index was largely maintained, and compliance was good, although probably enhanced by close supervision.