Intra-operative monitoring of vagal nerve activity with wire electrodes

Inappropriate elevation of bispectral index values in robot assisted thyroidectomy with electromyographic endotracheal tube -A case report-

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.

Damage to the cuff of EMG tube at endotracheal intubation by using a lightwand -A case report-

Electromyogpraphic endotracheal tube (EMG tube) is a new device used to monitor recurrent laryngeal nerve integrity during thyroid surgery. The EMG tube has 2 pairs of electrodes on the surface of silicon-based tube reached to inner space of tube cuff. We experienced an unusual endotracheal tube-related problem from the distinct structural feature of the EMG tube. In this case, we intubated a patient who had difficult airway with the EMG tube using a lightwand. After successful endotracheal intubation, we could not expand the pilot balloon and ventilate the patient effectively. We removed the EMG tube and found that one of electrodes of the EMG tube is bended and made a right angle with the long axis of the tube, and perforated the tube cuff. So we report this case to make anesthesia providers aware that much more attention is needed to use EMG tube during endotracheal intubation.