Efficacy of a FOT-based auto-CPAP device for the treatment of obstructive sleep apnea

Background: The forced oscillation technique (FOT) is a valid method to asses the airway resistance. The APAP device under focus implements this technology in a new way and combines FOT with respiratory flow analysis to detect flattening and snoring to treat even partial obstructions effectively. This clinical study investigated therapeutic efficacy and pressure regulation of the APAP device in OSA. Methods: In this prospective cohort study, newly diagnosed OSA patients (AHI>15/h, <20% central respiratory events) were treated with the prismaLAB/prisma20A (Löwenstein Medical Technology GmbH) in APAP mode during an in-lab polysomnography (PSG) (APAP mode "standard", pressure 5-20 hPa). Patients showing mixed apneas in the diagnostic PSG were taken into accout for the analysis of loop gain (LG). Results: 45 patients were examined (16 f., 62 [53–73] y, BMI 32 [29–37] kg/m2). There was a significant reduction of respiratory events from AHI 34 [22–55]/h, oAHI 34 [22–49]/h, oAI 16 [6–34]/h, ODI 31 [19–54]/h to AHI 2 [1–6]/h, oAHI 1 [1–3]/h, oAI 0 [0–0]/h, ODI 2 [1–4]/h. The median pressure was 7 [5–10] hPa. Four patients showed treatment-emergent central sleep apnea (TE-CSA). They had a significantly higher mixed apnea index during diagnostic PSG (17 [4-28]/h vs 0 [0–2]/h). All values median [Q1–Q3]. Conclusions: The prisma20A, which combines FOT with respiratory flow analysis in a new way, highly significantly reduces respiratory events in OSA without indication for inadequate pressure increases. A high portion of mixed apneas in the diagnostic PSG could possibly be a predictor for TE-CSA. The LG analysis provides further insights as to its value for TE-CSA prediction.