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

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 x h(-1)) were enrolled. After a manual titration, subjects were randomly allocated to 2 months autoadjusting nasal CPAP (AutoSet), followed by 2 months with the AutoSet 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 x h(-1) in auto mode, and 3.7+/-0.3 x 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 cmH2O (p=0.04 with respect to manual) and peak pressure typically 1 cmH2O higher. Median (+/-SEM) leak was 0.181+/-0.006 L x s(-1) auto (and uncorrelated with AHI or pressure), 0.20+/-0.006 L x 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.