Efficacy and patient satisfaction with autoadjusting CPAP with variable expiratory pressure vs standard CPAP: a two-night randomized crossover trial.

Expiratory pressure relief (C-Flex) technology monitors the patient's airflow during expiration and reduces the pressure in response to the patient. Increased comfort levels associated with C-Flex therapy have potential to improve patient adherence to therapy. The purpose of this study was to assess the combination of autoadjusting CPAP (APAP) and C-Flex in terms of (1) treatment efficacy, and (2) patient preference when compared to standard CPAP. Fifteen patients who had previously undergone formal CPAP titration polysomnography were treated with either one night of the APAP with C-Flex or one night of conventional CPAP, in a crossover trial. Patient satisfaction levels were recorded using visual analog scales (VAS) on the morning after the study. Mean patient age was 50 +/- 12 years, body mass index (BMI) was 36 +/- 6 kg/m(2), baseline AHI was 53 +/- 31 events/h, and CPAP Pressure was 11 +/- 2 cm/H(2)O. APAP with C-Flex was as effective as CPAP, with no differences detected in sleep latency (17 +/- 5 vs 12.3 +/- 3 min, p = 0.4), or respiratory indices (AHI of 4.2 +/- 2 vs 2.4 +/- 0.7 events/h, p = 0.1). VAS scores (scale 0-10) indicated a trend towards increased patient satisfaction while using APAP with C-Flex (7.9 vs 7.2, p = 0.07). 10 patients expressed a preference for APAP with C-Flex (VAS, 0 to 10) over standard CPAP (total positive score of 68, mean score of 4.8 +/- 4.3). One patient expressed no preference. Four patients expressed a preference for CPAP (total positive score of 13, mean score of 0.9 +/- 1.9) (APAP with C-Flex vs standard CPAP, p < 0.01 paired t test). APAP with C-Flex eliminates sleep disordered breathing as effectively as standard CPAP. Patients indicated a preference for APAP with C-Flex suggesting a possible advantage in terms of patient adherence for this mode of treatment.