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Med Sci Monit. 2003 Aug;9(8):CR353-8.

Auto-adjusting CPAP based on impedance versus bilevel pressure in difficult-to-treat sleep apnea syndrome: a prospective randomized crossover study.

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Department for Pneumology, Allergology and Sleep Medicine, University Witten/Herdecke, Germany.



Although continuous positive airway pressure therapy (CPAP) is the treatment of choice for obstructive sleep apnoea syndrome (OSAS), there is a portion of patients in which CPAP is not usable. Bilevel treatment serves as an alternative for these patients. For uncomplicated OSAS, auto-adjusting CPAP based on the forced oscillation technique (APAPFOT) has proved to be equally as effective as constant CPAP, and is preferred by the patients. The aim of this study was to investigate the question whether, in the event of primary CPAP intolerance, high pressures (>or =12 cm H2O) or SAS with > or =10% central respiratory disorders, APAPFOT is as effective as bilevel therapy in reducing respiratory disturbances.


27 patients (23 m, 4 f, age 57.2+/-13.1 years, BMI 33.5+/-7.8 kg/m2) were treated with bilevel and APAPFOT for 6 weeks each in a prospective randomized cross-over study. The efficacy of the treatment modes was examined polysomnographically.


Both modalities significantly improved the respiratory disturbances (AHI: baseline 49+/-27.3/h, bilevel 9.8+/-12.5, p<0.01, APAPFOT 13.8+/-13.2, p<0.01) and sleep quality (arousals: baseline 43+/-28.3/h, bilevel 17.7+/-8.8, p<0.01, APAPFOT 20.5+/-10.7, p<0.01), with no significant differences between the modalities. Under APAPFOT, mean treatment pressure was substantially reduced (bilevel 8.3+/-2.5, APAPFOT 5.1+/-1.7, p<0.01). The majority of patients gave preference to APAPFOT for long-term treatment (21 vs. 6 patients, p<0.05).


In patients with difficult-to-treat OSAS, APAPFOT has proved to be just as effective as bilevel therapy, but has the advantage of meeting with greater acceptance.

[Indexed for MEDLINE]

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