Minimum Current for Train-of-four Monitoring

Neuromuscular monitoring during general anesthesia is important to make sure adequate muscle relaxation during operation and adequate recovery of muscle power and spontaneous breathing during emergence from general anesthesia. The neuromuscular monitoring is usually using electrical stimulants and the method called train-of-four (TOF) is representative. Because it uses electrical stimulants, the patients could be uncomfortable and feel pain during the monitoring when the patients are conscious. Lowering the current of the stimulants would be helpful in reducing the pain, but there is a concern that the TOF results performed in lower current would be underestimated or inaccurate. Therefore, the investigators want to find the minimal current for TOF monitoring that shows adequate TOF results.