Minimum Anaesthesia Concentration of Lidocaine Required for Sciatic Popliteal Block

Study Overview
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Brief Summary
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using a biased-coin design up-down sequential method, different concentration of lidocaine will be used for popliteal block After 45 successful block (positive response), the data will be used to calculate the minimum lidocaine concentration that can result in successful popliteal block in 90% of patients

Detailed Description
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The response of a patient determined the lidocaine concentration given to the next patient (a biased-coin design up-down sequential method). If a patient had a negative response, the lidocaine concentration was increased by 0.1% w/v in the next patient. If a patient had a positive response, the next patient was randomized to receive the same lidocaine concentration (with probability of 0.89), or to receive a concentration 0.1% w/v less (with probability of 0.11).

Official Title
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Successful Popliteal Block Using Lidocaine; What is the Minimum Effective Anesthesia Concentration (MEAC90)

Conditions
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Orthopedic Procedures

Intervention / Treatment
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* Drug: Lidocaine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: orthopedic foot or ankle surgery day case surgery Exclusion Criteria: patients <18y, ASA class greater >III, obese (BMI >30), patients with low body weight, who required lidocaine dose is of more than 4.5mg.kg-1 peripheral neuropathy, motor weakness, infection at the injection site any contraindications for medications in the study.

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: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: lidocaine concentraion<br>the popliteal block will be performed (once) in all patients using 20 ml of lidoacine. The response of a patient determined the lidocaine concentration given to the next patient (a biased-coin design up-down sequential method). If a patient had a negative response (failed block), the lidocaine concentration was increased by 0.1% w/v in the next patient. If a patient had a positive response (successful block), the next patient was randomized to receive the same lidocaine concentration (with probability of 0.89), or to receive a concentration 0.1% w/v less (with probability of 0.11). | Drug: Lidocaine<br>* patients will receive different lidocaine concentrations<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| successful popliteal block (positive response) | Sensory block will be assessed using pinprick sensation. Complete sensory block = unable to recognize pinprick sensation. Intra-operative pain will be assessed using Visual Analogue Scale (VAS) 0 = No pain, 10 = Worst imaginable pain. Successful block = complete sensory block + pain free surgery (VAS = 0). | 30 min to 3 hour after the block | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| motor block | degree of motor weakness | 30 min after the block | 
| motor recovery | complete recover of the motor power | 3 hours till full recovery | 
| analgesic duration | requesting painkiller | few hours after block | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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foot and ankle, day case surgery