睡眠時無呼吸症候群に対する簡易モニター装置(モルフェウス(R))の評価

Sensitivity and Specificity of Automated Portable Device for Diagnosing Sleep Apnea Syndrome(Morphase(R))

要旨

　鼻腔圧とパルスオキシメーターを指標とした簡易装置(モルフェウス^(R))の有用性を検討する目的で，患者20名にポリソムノグラフ(PSG)検査と簡易装置を同時に実施し，外来患者46名で簡易装置検査の自動判定と目視解析の結果を比較した．PSGによる呼吸障害指数(RDI)と簡易装置による無呼吸指数(AHI)の関係はY＝0.608X－0.377(r²＝0.907)で，簡易装置は無呼吸を約40%過小評価していた．RDIを実睡眠時間で補正するとY＝0.716X＋0.216となり，睡眠時間による過小評価は約10%と推定された．自動解析での呼吸イベントの誤認率は極めて低かったが，目視と自動解析AHIの関係はY＝0.765X－1.593(r²＝0.951)で，自動解析はAHIを約23%過小評価すると推定された．また，鼻腔圧のみによる自動解析はAHIが10～30/hrの患者を過大評価する傾向があった．以上より，カットオフ値を適切に設定すれば，簡易装置による自動解析はスクリーニングに十分な感度と特異性があると結論した．

Summary

　We investigated the sensitivity and specificity of an automated portable device for diagnosing sleep apnea syndrome (Morphase^(R)). In 20 patients who underwent a polysomnograph (PSG), Morphase^(R) was concurrently applied. In another 46 patients who received screening test with Morphase^(R), apnea-hypopnea indexes (AHIs) determined by the automated system and those with manual analyses were compared. There was a good correlation between AHI and respiratory distress indexes (RDIs) determined by PSG. The regression line was Y＝0.608X－0.377 suggesting that Morphase^(R) underestimates AHI by 40%. When RDI was corrected by actual sleep time, the regression line became Y＝0.716X＋0.216 suggesting that the contribution of sleep time to Morphase-determined AHI was approximately 10%. The regression line representing the relationship between automated AHI and manually determined AHI was Y＝0.765X－1.593. This result suggested that the automated system underestimated AHI by 23%. When AHI was determined only from nasal pressure, AHIs were overestimated from 10 to 30/hr. In conclusion, Morphase^(R) has a good specificity and sensitivity for determination of which patients require PSG study.