Figure 4
AUC comparison between Nihon Kohden SpO2 and Masimo SpO2 for patients with SaO2 < 90% and SaO2 ≥ 98%. The blue line represents Masimo SpO2 measurements, and the red line represents Nihon Kohden SpO2. The vertical axis represents true positive rate calculated by sensitivity, and the horizontal axis represents false positive rate calculated by (1—specificity). To detect SaO2 < 90%, the area under the receiver operating characteristic curves (AUCs) were 0.966 using the Nihon Kohden and 0.971 using the Masimo monitor. When cut off point was set at SpO2 90% in Nihon Kohden and Masimo, its sensitivity and specificity were 62.8% and 99.0% in Nihon Kohden SpO2, and 56.9% and 99.3% in Masimo SpO2, respectively. There was no statistically significant difference in the AUCs between both monitors (P = 0.530). Regarding SaO2 ≥ 98%, the AUCs were 0.837 using the Nihon Kohden and 0.835 using the Masimo monitor. When cut off point was set at SpO2 98% in Nihon Kohden and Masimo, its sensitivity and specificity were 87.1% and 66.2% in Nihon Kohden SpO2, and 90.8% and 58.7% in Masimo SpO2, respectively. However, there was no statistically significant difference in the AUCs of both monitors (P = 0841). AUC, receiver operating characteristic curve.
