The Staircase Phenomenon Implications on Neuromuscular Block Monitoring

Study Overview
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Brief Summary
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The staircase phenomenon could have repercussions on the onset and recovery time following administration of a neuromuscular blocking agent. The investigators aim to assess the magnitude of the staircase phenomenon and its impact on various aspects of neuromuscular blockade with a randomized controlled double blind trial.

Official Title
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The Staircase Phenomenon and His Implications on Neuromuscular Block Monitoring During General Anesthesia

Conditions
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Neuromuscular Blockade Monitoring

Intervention / Treatment
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* Device: Tetanus stabilization of baseline


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ASA (American Society of Anesthesiology surgical risk scale) grade I - II Surgery not involving airway performed under general anaesthesia with neuromuscular blocker Exclusion Criteria: Pregnancy BMI (Body Mass Idex) > 35 Kg/m2 Anticipated difficult airway Chronic kidney or hepatic failure Neuromuscular disease Medication that has known interactions with neuromuscular blockers Hemodynamic failure Anticipated large blood loss

Ages Eligible for Study
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Minimum Age: 18 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: Other
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Tetanic Group<br>A Tetanic stimulation (Tetanus stabilization of baseline) is administered to the monitorized arm before calibrating the neuromuscular block monitor. Then Train-of-four (TOF) stimuli are administered every 20 seconds for 20 minutes. | Device: Tetanus stabilization of baseline<br>* Administering a Tetanic stimulus before baseline stabilization shortens the stabilization period of baseline of a neuromuscular block monitor. This acts on the baseline value<br>|
| No Intervention: Control Group<br>Conventional monitor baseline stabilization: Train-of-four stimuli are administered every 20 seconds for 20 minutes | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Difference in Block Onset time difference (seconds) | Onset time is the time between Train of Four (TOF) at the moment of injection of neuromuscular blocking drug and the minimum value reached (onset of neuromuscular block) | rom 0 seconds up to 240 seconds after neuromuscular block administration at the beginning of surgery. Time frame is the duration of general anesthesia before, during and after surgery (up to 4 hours). | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Difference in time until recovery of a TOF ratio (TOFr) of 0.9 | Time until recovery of a TOF ratio of 0.9 (reversal of neuromuscular block as assessed by the monitor). During recovery phase stimuli regain height until all four stimuli of the Train-of-Four are present. Train-of-Four ratio is the ratio between the fourth and the first stimuli (T4/T1). | From administration of neuromuscular blocking drug until spontaneous reversal (up to 4 hours). Time frame is the duration of general anesthesia before, during and after surgery (up to 4 hours). | 
| Difference in TOFr 0.9 Normalized | Time until recovery of a TOF ratio of 0.9 normalized to baseline TOR ratio after calibration. (e.g. if baseline TOF ratio is 1.1, normalized TOF ratio 0.9 is: 1.1 x 0.9 = 0.99) | From administration of neuromuscular blocking drug until spontaneous reversal at this specified point (up to 4 hours). Time frame is the duration of general anesthesia before, during and after surgery (up to 4 hours). | 
| Difference in time until recovery of 25% of maximum twitch height ot T1 stimulus (DUR25) | Difference in time until recovery of 25% of maximum twitch height ot T1 stimulus during recovery phase. During recovery phase stimuli begin to recover and their height increases. This outcome is the time between the beginning of neuromuscular block until recovery of 25% of height of the first stimulus of the Train-of-Four.recovery phase. During recovery phase stimuli begin to recover and their height increases. This outcome is the time between the beginning of neuromuscular block until recovery of 25% of height of the first stimulus of the Train-of-Four (TOF) | From administration of neuromuscular blocking drug until spontaneous reversal at this specified point (up to 4 hours). Time frame is the duration of general anesthesia before, during and after surgery.(up to 4 hours) | 
| Time between 25% and 75% of maximum twitch height recovery of T1 stimulus | Time between 25% and 75% height recovery of maximum twitch height in the recovery phase. | From administration of neuromuscular blocking drug until spontaneous reversal (up to 4 hours). Time frame is the duration of general anesthesia before, during and after surgery (up to 4 hours). | 
| Difference between first stimulus of Train-of-Four ratio at baseline | Difference between T1 at baseline. Train-of-Four ratio is the administration of four consecutive stimuli to the monitored muscle. These stimuli are named T1,T2,T3,T4. This is the difference between tow arms oh T1 height at baseline | Single measurement of muscle response after calibration procedure at the beginning of data recording after randomization. It is not a time-to-event variable | 
| Difference between T1 height after stabilization period of 20 minutes | Difference between T1 height after stabilization period of 20 minutes | Single measurement after 20 minutes stabilization period after beginning of neuromuscular stimulation. It is not a time-to-event variable | 
| Difference between TOF ratio at baseline time | Difference between TOF ratio at baseline time | Single measurement of muscle response after calibration procedure at the beginning of data recording. | 
| Difference between TOF ratio after stabilization period time | Difference between TOF ratio after stabilization period time | Single measurement after 20 minutes stabilization period after beginning of neuromuscular stimulation. | 
| Monitor Sensitivity difference between groups | Sensitivity parameter is set by monitor after calibration. | Single value no time frame. Sensitivity is internally set by the monitor during calibration (at the beginning of data recording after randomization) | 
| Monitor Amperage Intensity after calibration difference (milliAmperes, mA) | Monitor Amperage Intensity is set by the monitor after calibration | Single value no time frame. Sensitivity is internally set by the monitor during calibration (at the beginning of data recording after randomization) | 
| T1/TOFratio relationship difference | During recovery phase T1 over TOF ratio will be calculated and the difference between two groups will be assessed. | Ratio of specified values recorded by the monitor at the beginning of surgery until onset of neuromuscular block (up to 180 seconds) and during spontaneous recovery up to 4 hours until end of anesthesia |