Minimum Current for Train-of-four Monitoring

Study Overview
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Brief Summary
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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.

Official Title
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Determination of the Minimum Current for Train-of-four Monitoring by Acceleromyography and Electromyography During the Recovery From General Anesthesia

Conditions
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Anesthesia, Anesthesia Recovery Period, Neuromuscular Blockade

Intervention / Treatment
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* Device: Train-of-four (TOF)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 20-65 Scheduled for an elective surgery ASA physical status 1 or 2 Exclusion Criteria: BMI > 25 kg/m2 Neuromuscular disease Decreased renal function Neurologic disorder Impossible to cooperate or communicate

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Supportive Care
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Participants<br>The participants will be applied AMG and EMG on each arm of both arms when they finish routine monitoring before the induction of general anesthesia. After the participants being unconscious, we will find each participant's supramaximal current before injecting the neuromuscular blocking agents. During the operation, when the TOF count reaches 4 again and the height of T1 reaches 50% of baseline, we perform TOF tests using 4 currents (Supramaximal current, 0.7×supramaximal current, 0.5×supramaximal current, 0.3×supramaximal current), three times for respective current to figure out that low current can show the same level of TOF ratio as the supramaximal current. When the operation ends and the T1 reaches 100% of baseline, we perform TOF tests with 4 currents again. In the postanesthesia care unit, we use EMG only and perform TOF tests with 4 currents again. The participants can feel pain by the stimulants during the tests, so if they refuse the tests, we stop the tests and record it. | Device: Train-of-four (TOF)<br>* Give 4 electrical stimulants on the ulnar nerve to see if the 4 responses (T1   T4) of adductor pollicis fade or not. If there's no neuromuscular block, it shows no fade, or it fades. When an operation is over under general anesthesia, we use the ratio of the height of T4 to T1, and the ratio is over 90%, the neuromuscular block is recovered enough to extubation.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Minimal current for TOF | The minimal current among the four currents we use which is showing not significantly lower TOF ratio than TOF ratio of supramaximal stimulant. | During the operation, from the height of T1 reaches back to the baseline, to the extubation of tracheal tube when the general anesthesia is over. |