Accuracy of the Auto Scoring by the S9 CPAP in Patients with Obstructive Sleep Apnea

Abstract

Background and Objective Several continuous positive airway pressure (CPAP) devices currently in use automatically estimate and provide information of the residual respiratory events such as apnea-hypopnea index (AHI), apnea index (AI), and hypopnea index (HI). To compare the auto scoring of the residual respiratory events using the S9 CPAP device with simultaneous manual scoring and identify factors that are associated with difference between auto scoring and manual scoring in patients with OSA. Methods Patients with moderate to severe OSA titrated manually using S9 CPAP device were included. The correlation between auto scoring and manual scoring was assessed during an overnight standard in-hospital CPAP titration. Results Eighty-six patients with moderate to severe OSA were included. There was a strong correlation between auto scoring and manual scoring on AHI (r = 0.74, p < 0.001), with a stronger correlation on the AI (r = 0.86, p < 0.001), and a weaker correlation on HI (r = 0.56, p < 0.001). Overall, S9 auto scoring tended to underestimate the AHI (mean AHI difference: −1.30) owing to the strong underestimation on HI. Higher BMI, higher AHI from diagnostic polysomnography, higher leakage and lower oxygen saturation were independent factors for greater difference between auto scoring and manual scoring. Conclusions Auto scoring showed strong correlation with manual scoring. However, auto scoring of S9 CPAP tended to underestimate the AHI, as compared to manual scoring. Characteristic features of severe OSA were associated factors for difference between auto scoring and manual scoring.

Keywords

• Obstructive sleep apnea
• Auto scoring
• Manual scoring
• S9 CPAP
• AHI
• Auto-CPAP