To shorten induction time, some anesthesiologist gives a priming dose of muscle relaxant before starting Neuromuscular Transmission monitor (NMT). To properly evaluate neuromuscular function during the surgury, baseline supramaximal stimulation of the monitored nerve is mandatory. Not knowing if the priming dose of muscle relaxant affects the supramaximal stimulation current setting, The investigators designed this study to find out.

The NMT monitor module automatically determines the current needed for the supramaximal stimulus, and maintains this current throughout the procedure.

The supramaximal current is the current above which there is no increase in the evoked muscle response. At this stimulus current, all motor units are firing in response to nerve stimulation. According to previous studies, the current was significantly increased in the presence of edema and peripheral neuropathy. In this study, the route of administration, dosage, dosage regimen, and treatment period are basically the same as the investigators anesthesia department's routine procedure for general anesthesia. The difference will be the time the investigators set between the priming dose to final dose of rocuronium is 2 minutes. The investigators use 2 minutes as the peak effect of rocuronium is 105±36S.

To properly evaluate neuromuscular blockade during the surgery, baseline supramaximal stimulation of the monitored nerve is mandatory. Not knowing if the priming dose of muscle relaxant affects the supramaximal stimulation current setting, the investigators designed this study.

Inclusion Criteria:

• Patients receiving general anesthesia and use rocuronium for induction

Exclusion Criteria:

• Muscular disease
• Peripheral neuropathy
• Difficult airway or difficult mask ventilation
• Allergy to study related medication
• Pregnant woman
• < 20-year-old or > 65-year-old
• BMI <18.5 or BMI>24.9

de-identified raw data