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

Abstract

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.