Two months auto-adjusting versus conventional nCPAP for obstructive sleep apnoea syndrome

Abstract

Autoadjusting nasal continuous positive airway pressure (CPAP) greatly reduces the apnoea/hypopnoea index (AHI), and affords a significant reduction in median pressure (P50) compared with manually titrated conventional nasal CPAP. The aim of the present study was to test whether these benefits were maintained in the medium term at home, in a double-blind crossover study. Ten sequential subjects (mean AHI 52.9.h-1) were enrolled. After a manual titration, subjects were randomly allocated to 2 months autoadjusting nasal CPAP (AutoSet(TM)), followed by 2 months with the AutoSet(TM) device in fixed pressure mode at the manually titrated pressure, or vice versa. The machine-scored AHI, P50, and median leak were recorded on 12 nights in each arm, and averaged. Mean±SEM AHI was 4.0±0.3·h-1 in auto mode, and 3.7±0.3·h-1 in manual mode (NS). Mean±SEM P50 was 7.2±0.4 cmH2O auto, 9.4±0.6 cmH2O manual, average reduction 23±4% (p<0.0001). Auto 'recommended' pressure was (mean±SEM) 10.1±0.5 cm2O (p=0.04 with respect to manual) and peak pressure typically 1 cmH2O higher. Median (±SEM) leak was 0.181±0.006 L·s-1 auto (and uncorrelated with AHI or pressure), 0.20±0.006 L·s-1 manual (p=0.003). Compliance was 6.3±0.4 h in auto mode and 6'1±0.5 h in fixed mode (NS). Apnoea/hypopnoea index during 2 months of home autoadjusting nasal continuous positive airway pressure is comparable to that during conventionally titrated fixed pressure continuous positive airway pressure, while affording a 23% reduction in median pressure but no increase in compliance. Leak did not importantly affect autoadjustment. (C) ERS Journals Ltd 2000.