Strategy for Maintaining Partial Neuromuscular Blocking Adequate for Motor Evoked Potential During Neurosurgery

Study Overview
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Brief Summary
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The maintenance of partial neuromuscular blocking during general anesthesia for neurosurgery is essential for intraoperative motor-evoked potential monitoring. However, the precise strategy of administering neuromuscular blocking agent for obtaining that goal has not been established. Therefore, the investigators tried to find the optimal initial dose of vecuronium infusion and determine the adequate goal of neuromuscular blocking as guided by neuromuscular transmission module (M-NMT Module, Datex-Ohmeda Inc, Helsinki, Finland).

Detailed Description
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The maintenance of partial neuromuscular blocking during general anesthesia for neurosurgery is essential for intraoperative motor-evoked potential monitoring. However, the precise strategy of administering neuromuscular blocking agent for obtaining that goal has not been established. Therefore, the investigators tried to find the optimal initial dose of vecuronium infusion and determine the adequate goal of neuromuscular blocking as guided by neuromuscular transmission module (M-NMT Module, Datex-Ohmeda Inc, Helsinki, Finland). Previously, one to two counts of response to TOF stimulation has been considered to be primary goal of partial neuromuscular blocking needed for intraoperative motor evoked potential monitoring. However, the visualization of twitch height of response to TOF stimulation has been possible with the help of NMT module. For adequate motor evoked potential monitoring, twitch height of T1 or T2 is also as important as simple count of TOF stimulation. The investigators tried to establish a vecuronium infusion strategy as guided by not only count of TOF stimulation but also twitch height of T1 or T2.

Official Title
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Determination of ED50 and ED95 of Vecuronium Infusion Dose for Maintaining Response of Train of Four Less Than 2 During the MEP Monitoring for Neurosurgery

Conditions
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Brain Surgery With Motor Evoked Potential Monitoring, Spine Surgery With Motor Evoked Potential Monitoring

Intervention / Treatment
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* Other: TOF count guided adjustment
* Other: T1/ T0 guided adjustment
* Other: T2/ T0 guided adjustment


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult Patients undergoing neurosurgery with intraoperative motor evoked potential monitoring Exclusion Criteria: Patients who can not undergo motor evoked potential monitoring due to central or peripheral neuromuscular disease (e.g. Cerebral palsy, Myasthenia gravis, Acute spinal injury, neurologic shock) Patients with hepatic or renal disease with altered metabolism of vecuronium Patients with medication which influence the metabolism of vecuronium (e.g. calcium channel blocker, aminoglycoside antibiotics, Lithium, MgSO4)

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 70 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

Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: TOF count guided group<br>adjustment of neuromuscular blocking agent infusion dose every 15 minute as guided by No. of response to TOF stimulation | Other: TOF count guided adjustment<br>* adjustment of vecuronium infusion dose every 15 minutes as guided by No. of response to TOF stimulation displayed by NMT module.<br>|
| Experimental: T1/T0 guided group<br>adjustment of neuromuscular blocking agent infusion dose every 15 minute as guided by T1 twitch height as compared with control (T0) | Other: T1/ T0 guided adjustment<br>* adjustment of vecuronium infusion dose every 15 minutes as guided by T1 twitch height as compared with baseline (T0) displayed by NMT module.<br>|
| Experimental: T2/ T0 guided group<br>adjustment of neuromuscular blocking agent infusion dose every 15 minute as guided by T2 twitch height as compared with baseline (T0) | Other: T2/ T0 guided adjustment<br>* adjustment of vecuronium infusion dose every 15 minutes as guided by T2 twitch height as compared with baseline (T0)displayed by NMT module.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Amplitude of MEP monitoring | the value of MEP amplitude every 30 min during MEP monitoring | every 30 min during MEP monitoring | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| latency of MEP monitoring | latency of MEP monitoring every 30 min during MEP monitoring | every 30 min during MEP monitoring | 
| Incidence of patient's spontaneous movement | Incidence of patient's spontaneous movement during MEP monitoring | from start to end of the MEP monitoring, an expected average of 4 hours | 
| Overall assessment of MEP monitoring quality | overall assessment of MEP monitoing quality provided by the electrophysiologist Grade I : no problem all through the monitoring Grade II : difficulty of monitoring for less than 5 min Grade III : difficulty of monitoring for 5 min to 30 min Grade IV : Difficulty of monitoring for more than 30 min | from start to end of the MEP monitoring, an expected average of 4 hours | 
| Incidence of patient's spontaneous respiration | Incidence of patient's spontaneous respiration as determined by end-tidal CO2 curve monitoring | from start to end of the MEP monitoring, an expected average of 4 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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infusion dose, vecuronium, motor evoked potential, neuromuscular blocking agent