The Usefulness of Respiratory Mechanic Instability in Evaluating the Effect of Continuous Positive Airway Pressure for Obstructive Sleep Apnea

Objectives: Respiratory mechanics instability (RMI) based on paradoxical movement is correlated with respiratory disturbance such as apnea-hypopnea index (AHI) and reflects the severity of obstructive sleep apnea (OSA). The purpose of this study was to identify RMI as a method for assessing the effectiveness of continuous positive airway pressure (CPAP) in the management for OSA. Methods: A total of 71 consecutive OSA patients with CPAP titration were included in this study. We compared sleep (sleep efficiency, arousal index, and sleep stages), respiratory (AHI, oxygen desaturation index ≥3% [ODI3], and lowest oxygen saturation), and RMI parameters (events, index, duration, and % of stage duration) between diagnostic polysomnography and CPAP titration data. Results: All RMI parameters (events [157.5 ± 80.9 vs 80.0 ± 47.1; P <.001], index [25.3 ± 12.4 vs 12.7 ± 7.0; P <.001], duration [182.6 ± 96.2 vs 79.8 ± 88.9; P <.001], and % of stage duration [49.0 ± 24.4 vs 20.5 ± 21.3; P <.001]) were significantly improved by the alleviation of obstructive respiratory disturbance parameters (AHI [45.1 ± 23.0 vs 4.2 ± 4.3; P <.001], ODI3 [44.9 ± 22.6 vs 4.8 ± 4.6; P <.001], and lowest oxygen saturation [77.7 ± 7.3 vs 89.3 ± 3.8; P <.001]) compared to diagnostic polysomnography and CPAP titration data. Conclusion: RMI may be a useful method for evaluating the effect of CPAP in OSA patients.