Pressure Modification for Improving Usage of Cpap Machines for Obstructive Sleep Apnoea

A Cochrane review [Abstract] 1 included 45 studies on the efficacy of pressure level modifications and additional humidification in increasing CPAP machine usage, with a total of 1 874 subjects.

• Auto-CPAP (30 studies, n=1 136): Cross-over studies: difference in machine usage 0.21 hours/night (0.08 to 0.35, statistically significant; 16 trials, n=450) in favour of auto-CPAP, but this difference is of questionable clinical significance. Overall reduction of 0.64 units (-0.12 to -1.16) in Epworth Sleepiness Scores between pressure modes in favour of auto-CPAP. Parallel group trials: Pooled effect estimates detected a similar but not statistically significant difference for average nightly machine usage, and there was either no significant difference in Epworth Sleepiness Scores. More participants preferred auto-CPAP to fixed CPAP where this was measured.
• Bi-level PAP (6 studies, n=285): no significant differences were observed in machine usage. One small study found no difference in preference.
• C-Flex (6 studies, n=318): no significant difference was observed in machine usage.
• Humidification (3 studies, n=135): there were conflicting findings between the studies. Two parallel group trials found no significant difference in machine usage, whereas a cross-over study found a significant difference.

Comment: The quality of evidence is downgraded by limitations in study quality and by indirectness (differences in studied patients).

References

• Smith I, Lasserson TJ. Pressure modification for improving usage of continuous positive airway pressure machines in adults with obstructive sleep apnoea. Cochrane Database Syst Rev 2009;(4):CD003531. [PubMed]