Validity of sheet-type portable monitoring device for screening obstructive sleep apnea syndrome

Purpose: The SD-101 is a non-restrictive sheet-like medical device that measures sleep-disordered breathing using pressure sensors that can detect the gravitational alterations in the body that accompany respiratory movement. One report has described that the screening specificity of the SD-101 for mild to moderate obstructive sleep apnea syndrome (OSAS) is relatively low. The present study examines whether the accuracy of the SD-101 for OSAS screening is improved by simultaneously measuring percutaneous oxygen saturation (SpO₂). Methods: Sixty consecutive individuals with suspected OSAS consented to undergo overnight polysomnography (PSG) together with simultaneous measurements of SD-101 and SpO₂ at our laboratory. Results: The apnea-hypopnea index (AHI) determined from PSG and the respiratory disturbance index determined from SD-101 measurements significantly correlated (SD-101 alone: r = 0.871, p < 0.0001; SD-101 with SpO₂: r = 0.965, p < 0.0001). Bland-Altman plots showed a smaller dispersion for the SD-101 with SpO₂ than for the SD-101 alone. The SD-101 with SpO₂ detected an AHI of >15 on PSG with a sensitivity and specificity of 96.9 and 90.5 % compared with 87.5 and of 85.7 %, respectively, of the SD-101 alone. Conclusions: Simultaneously measuring SpO₂ improved the accuracy of the SD-101 for OSAS screening. Furthermore, this modality appears to offer high sensitivity and specificity for detecting even moderately severe OSAS.