Abstract
Current Auto-CPAP devices retain information on their use, pressure, leaks and respiratory events and can operate also as CPAP. We evaluated reliability of AHI values recorded by two devices (Auto-Set Spirit II - 22 pts and REMstar auto M series -15 pts) as compared to those recorded by the Embletta, in a group of 37 consecutive adults with OSAS (mean age: 58 yrs; 14 F; BMI range: 24-61). Each patient underwent the following procedures: a. baseline ambulatory recording by Embletta; b. 3-7 nights recordings by Auto-CPAP; c. 3-7 nights recordings by CPAP; d. ambulatory recording by Embletta while using CPAP titrated on the basis of the Auto-CPAP records. Respiratory events were assessed by manual analysis of Embletta traces or based on at least 4 nights records of Auto-CPAP devices. We selected only nights during which patients used the device at least 5 hrs and leaks were < 0.5 L/s. Baseline AHI ranged between 9 and 91 ev/hr. The 95th percentile airway pressure as determined by the Auto-CPAP device was 9.5±1.5 cmH2O. The AHI measured by CPAP during 4 nights was 3.9±1.7 (AI: 1.2±1.2; HI 2.8±1.8).The AHI during CPAP was 2.2±2.1 (AI: 0.7±1.6; HI:1.5±1.7). Difference plots for Bland and Altman analysis were 1.7 for AHI, 0.4 for AI and 1.3 for HI. Mean difference between AHI values measured during CPAP and measured by Auto-Set Spirit II and REMstar auto M was significantly different (2.32 vs 0.76; p<0.015). The results of this study suggest that AHI values measured by CPAP in OSAS are reliable as compared to those measured by a portable recorder and that small but significant differences exist between different CPAP devices.
- © 2011 ERS
