수면정신생리

수면정신생리 (9권1호 34-40)

Diagnosis of Obstructive Sleep Apnea Syndrome Using Overnight Oximetry Measurement

혈중산소포화도검사를 이용한 폐쇄성 수면무호흡증의 흡증의 진단

Youn, Tak;Park, Doo-Heum;Choi, Kwang-Ho;Kim, Yong-Sik;Woo, Jong-Inn;Kwon, Jun-Soo;Ha, Kyoo-Seob;Jeong, Do-Un;

Department of Psychiatry, Seoul National University College of Medicine and Department of Neuropsychiatry, Seoul National University Hospital;Department of Neuropsychiatry, Cheongju St. Mary''s Hospital;Department of Psychiatry, Seoul National University College of Medicine and Department of Neuropsychiatry, Seoul National University Hospital;Department of Psychiatry, Seoul National University College of Medicine and Department of Neuropsychiatry, Seoul National University Hospital;Department of Psychiatry, Seoul National University College of Medicine and Department of Neuropsychiatry, Seoul National University Hospital;Department of Psychiatry, Seoul National University College of Medicine and Department of Neuropsychiatry, Seoul National University Hospital;Department of Psychiatry, Seoul National University College of Medicine and Department of Neuropsychiatry, Seoul National University Hospital;Department of Psychiatry, Seoul National University College of Medicine and Department of Neuropsychiatry, Seoul National University Hospital;

Abstract

Objectives: The gold standard for diagnosing obstructive sleep apnea syndrome (OSAS) is nocturnal polysomnography (NPSG). This is rather expensive and somewhat inconvenient, however, and consequently simpler and cheaper alternatives to NPSG have been proposed. Oximetry is appealing because of its widespread availability and ease of application. In this study, we have evaluated whether oximetry alone can be used to diagnose or screen OSAS. The diagnostic performance of an analysis algorithm using arterial oxygen saturation ($SaO_2$) base on ''dip index'', mean of $SaO_2$, and CT90 (the percentage of time spent at $SaO_2$<90%) was compared with that of NPSG. Methods: Fifty-six patients referred for NPSG to the Division of Sleep Studies at Seoul National University Hospital, were randomly selected. For each patient, NPSG with oximetry was carried out. We obtained three variables from the oximetry data such as the dip index most linearly correlated with respiratory disturbance index (RDI) from NPSG, mean $SaO_2$, and CT90 with diagnosis from NPSG. In each case, sensitivity, specificity and positive and negative predictive values of oximetry data were calculated. Results: Thirty-nine patients out of fifty-six patients were diagnosed as OSAS with NPSG. Mean RDI was 17.5, mean $SaO_2$ was 94.9%, and mean CT90 was 5.1%. The dip index [4%-4sec] was most linearly correlated with RDI (r=0.861). With dip index [4%-4sec]${geq}2$ as diagnostic criteria, we obtained sensitivity of 0.95, specificity of 0.71, positive predictive value of 0.88, and negative predictive value of 0.86. Using mean $SaO_2{leq}97%$, we obtained sensitivity of 0.95, specificity of 0.41, positive predictive value of 0.79, and negative predictive value of 0.78. Using $CT90{geq}5%$, we obtained sensitivity of 0.28, specificity of 1.00, positive predictive value of 1.00, and negative predictive value of 0.38. Conclusions: The dip index [4%-4sec] and mean $SaO_2{leq}97%$ obtained from nocturnal oximetry data are helpful in diagnosis of OSAS. CT90${leq}$5% can be also used in excluding OSAS.

Keywords

Obstructive sleep apnea syndrome;Polysomnography;Oximetry;Arterial oxygen saturation;