0478 Novel Flow Limitation/Obstruction With Recovery Breath (FLOW) Event For Improved Scoring With Polysomnography And Home Sleep Apnea Testing. (27th April 2018) - Johnson, K G
Abstract: Introduction: Traditional apnea-hypopnea measures, especially with home sleep apnea testing (HSAT) without arousal data are inadequate for representing clinically significant events in mild obstructive sleep apnea (OSA). A new event type, F low L imitation/O bstruction W ith recovery breath (FLOW) is proposed. Our aim is to develop an event scorable with both HSAT and polysomnography (PSG) that will detect most obstruction related arousals and sleep disturbances. This study assesses the reliability of scoring FLOW. Methods: The following process was used (i) Development of initial definition, (ii) Training period and definition refinement, (iii) Reliability testing with 3 raters (1 registered sleep technologist and 2 boarded sleep medicine specialists) on ten 100-epoch sleep studies and two 100-sample tests from mild OSA patients, defined as patients with AHI using hypopneas with ≥4% desaturations <15 who were treated with CPAP. Training used ten different 100-epoch sleep studies and 2 other 100-sample tests. Modifications were made in the definition during the initial training period for clarification and the final definition was used for reliability testing. Results: FLOW is defined by at least 2 breaths with flow limitation or snoring followed by a higher amplitude recovery breath. FLOW is not scored when an apnea or hypopnea with ≥3% desaturation is present. Intraclass correlation (ICC) between 3 raters for ten 100 epoch samples was 0.91. The overall kappa for the presence of events between 3 scorers on 2 sets of 100 sample events was 0.84 and 0.87 demonstrating good agreement. Conclusion: We developed and confirmed the reliability of identifying a novel F low L imitation/ O bstruction W ith recovery breath (FLOW) event defined by airflow signal without EEG in patients with mild OSA. Scoring of FLOW across multiple raters after a training period is reliable. FLOW is meant to be scored in conjunction with apneas and hypopneas with desaturations. FLOW can be scored in both HSAT and PSG studies and should represent overall obstructive burden. Clinical significance of FLOW needs to be evaluated in future studies. Support (If Any): Baystate Health Research Pilot Award.