We report a case of an erroneously elevated bispectral index (BIS) during robot assisted thyroidectomy using an electromyographic endotracheal tube (EMG tube), which is safe and useful for laryngeal electromyographic monitoring. Ten minutes after start of the operation, a sudden increase of BIS value up to 98 was noticed. The BIS values were not decreased to < 65 with supplemental anesthetics. The anesthetic method was changed from total intravenous anesthesia to balanced anesthesia. The BIS sensor and monitor were changed and other models were used. These interventions did not alter BIS values. BIS levels remained between 60 and 70 throughout the main procedure and intermittently increased to the mid-90s without any trace of poor signal quality. At the end of the surgery, the BIS values returned to normal range. The patient did not complain of intraoperative recall. Knowledge of potential interference from the use of an EMG tube must be considered when interpreting BIS.

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The adhesion of PACVD - TiN films on tool steel (AISI M2) has been investigated as a function of interfacial chemistry and the metallic interlayer formation between TiN films and substrate steel. Prior to TiN deposition, thin metallic interlayers such as Ti, Cr, Cu films were deposited on a steel substrate with thickness range of 200 - 2000 A by Magnetron sputtering. TiN films were deposited by RF Glow Discharge PACVD technique using the gaseous mixture of TiCl4, N2, H2 and Ar at 520 °C. The adhesion strength of TiN films was investigated by Scratch Adhesion Tester (REVETEST model) with a diamond stylus. The critical load in adhesion test was about 35 N in the case of no metallic interlayer and it was increased up to 60 N in the presence of 200 Å thick Ti interlayer. The interfacial composition profile was investigated by Auger depth profile. The experimental results indicated that a thin Ti intermediate layer ([MATH] 600 Å) could increase the adhesion and the critical normal force in the scratch adhesion test was up to 60 N. In the case of Ti interlayer formation, the oxygen in the interfacial region plays an important role on the adhesion of TiN coating by the formation of a Ti(ON) type phase