Accuracy of BIS monitoring using a novel interface device connecting conventional needle-electrodes and BIS sensors during frontal neurosurgical procedures
Fig 5
(A) A representative captured image of the BIS monitor. The yellow line represents the EEG wave obtained from the left side (direct recording) and the blue line from the right side (indirect recording via the interface device). These two lines are nearly identical. (B-D) Representative BIS (B), EMG (C), and SQI (D) curves from a single patient with a strong agreement between direct and indirect BIS values. Curves from direct recording (orange lines) and indirect recording (blue lines) are superimposed. B’-D’ designate correlation analyses for BIS, EMG, and SQI, respectively. SQI for indirect recording was strongly affected by automatic impedance check every 10 minutes (D, blue line), resulting in the poor correlation coefficient of r2 = 0.6709, but it had a minimal impact on the correlation coefficients in BIS and EMG. The period between X: Anesthesia induction until recovery; grey bar: Intubated period; black bar: Surgical procedure; BIS: bispectral index, EMG: electromyogram, SQI: signal quality index.