Comparison of three ways to determine and deliver pressure during nasal CPAP therapy for obstructive sleep apnoea

Abstract

Background: The simplest method of initiating and maintaining therapeutic continuous positive airways pressure (CPAP) therapy for obstructive sleep apnoea (OSA) has not been established. Methods: Ninety eight subjects with OSA requiring CPAP treatment (more than 10 dips in oxygen desaturation of .4% per hour of sleep study and Epworth Sleepiness Score (ESS) .9) were randomised prospectively to three different methods of CPAP delivery for 6 months: (1) autotitration pressure throughout; (2) autotitration pressure for 1 week followed by fixed pressure (95th centile) thereafter; and (3) fixed pressure determined by algorithm (based on neck size and dip rate). Patients and investigators were blind to group allocation. One week after initiation the patients were routinely reviewed by sleep nurses. Study assessments took place before starting CPAP treatment and 1 and 6 months after to assess ESS, maintenance of wakefulness test, 24 hour blood pressure, general health (SF-36), and sleep apnoea related quality of life. CPAP internal monitoring data were also collected. Results: There were no significant differences in any of the outcome measures or CPAP monitoring data between the three groups. The 95th centile CPAP pressures delivered in the 6 month and 1 week autotitration groups were higher than in the algorithm group, but the median pressures were lowest in the 6 month autotitration group. Conclusions: The method of determining CPAP pressure for treatment of moderate to severe OSA makes no significant difference to clinical outcome measures. The autotitration CPAP machine used has no advantage in this setting over simpler methods of pressure determination.

Neural respiratory drive during apnoeic events in obstructive sleep apnoea

“…Nevertheless, the present authors believe that, if desired, the technique could be automated in the future, and that a technique for identifying and gating the ECG, as used by STOOHS et al [4], would probably be necessary. The authors also accept that, from a clinical perspective, a diagnosis that can be used for treatment decisions can be made using a respiratory sleep study alone for many patients with OSA [11]; however, as discussed hereafter, the present authors believe the current observations also to be of interest in some clinical situations. It might be suggested that the oesophageal instrumentation itself would disturb sleep, but this was not the case in the present patients, as evidenced by their total sleep time.…”

Titration procedures for nasal CPAP: Automatic CPAP or prediction formula?

“…Another large prospective multi-center trial compared the effects of a prediction formula, A-CPAP and manual titration, and found that these three methods were equally effective in improving subjective sleepiness and the apnea-hypopnea index (AHI) [6]. This was confirmed in a prospective study performed at home, where different methods of CPAP assessment resulted in comparable clinical outcomes [17]. However, despite increasing evidence that alternative methods for assessment of CPAP are effective, manual titration still prevails in official guidelines, although it is the most labour-intensive and expensive procedure.…”

Positive Pressure Therapy: A Perspective on Evidence-based Outcomes and Methods of Application

“…Employing a predictive equation represents another potential strategy to identify a therapeutic level of PAP (50,(101)(102)(103)(104). Most studies addressing this issue examined primarily patients with severe OSAH and evaluated relatively small sample sizes without describing power calculations.…”