Dexmedetomidine in Different Dose Levels as Adjuvant to Bupivacaine-induced Ultrasound-guided Femoral Nerve Block.

Study Overview
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Brief Summary
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The duration of sensory block after single dose of long acting local anesthetics is not sufficient to avoid the postoperative use of opioids. Alpha-2 adrenoceptor agonists such as clonidine have been shown to increase the duration of peripheral nerve block. Dexmedetomidine is a more potent and selective α-2-adrenoceptor compared to clonidine. To the best of our knowledge, the use of Dexmedetomidine in different dose levels as adjuvant to local anesthetic was not previously reported for femoral nerve block.

Official Title
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The Effects of Different Dose Levels of Peri-neural Dexmedetomidine on the Pharmacodynamic and Side Effects Profiles of Bupivacaine-induced Ultrasound-guided Femoral Nerve Block

Conditions
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Dexmedetomidine, Femoral Nerve Block, Arthroscopic Knee Surgery

Intervention / Treatment
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* Drug: peri-neural dexmedetomidine as adjuvant to bupivacaine in femoral nerve block
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: all patients with ASA physical status I or II, scheduled for arthroscopic knee surgery Exclusion Criteria: Patients who are refusing regional block, patients with diabetic peripheral neuropathy, renal or hepatic dysfunction, inflammation or infection at the puncture site, and history of allergic reaction to study medications

Ages Eligible for Study
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Minimum Age: 15 Years
Maximum Age: 45 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
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: group B: control bupivacaine group<br>Patient in this group will receive 25 ml bupivacaine 0.5% plus 1 ml normal saline peri-neurally | Drug: peri-neural dexmedetomidine as adjuvant to bupivacaine in femoral nerve block<br>* ultrasound guided femoral nerve block with injection of 25 ml bupivacaine 0.5% perineurally with 1 ml dexmedetomidine 25, 50, or 75 microgram perineurally. After adequate assessment of femoral nerve block, patients will be transferred to the operating room to receive a standard general anesthesia.<br>Drug: Placebo<br> <br> |
| Experimental: Group B-DEX 25 : Peri-neural Dexmedetomidine<br>Patients in this group will receive 25 ml of 0.5% bupivacaine plus 1 ml (25 microgram) Dexmedetomidine peri-neurally | Drug: peri-neural dexmedetomidine as adjuvant to bupivacaine in femoral nerve block<br>* ultrasound guided femoral nerve block with injection of 25 ml bupivacaine 0.5% perineurally with 1 ml dexmedetomidine 25, 50, or 75 microgram perineurally. After adequate assessment of femoral nerve block, patients will be transferred to the operating room to receive a standard general anesthesia.<br>|
| Experimental: Group B-DEX 50:Peri-neural Dexmedetomidine<br>Patients in this group will receive 25 ml of 0.5% bupivacaine plus 1 ml (50 microgram) Dexmedetomidine peri-neurally | Drug: peri-neural dexmedetomidine as adjuvant to bupivacaine in femoral nerve block<br>* ultrasound guided femoral nerve block with injection of 25 ml bupivacaine 0.5% perineurally with 1 ml dexmedetomidine 25, 50, or 75 microgram perineurally. After adequate assessment of femoral nerve block, patients will be transferred to the operating room to receive a standard general anesthesia.<br>|
| Experimental: Group B-DEX 75:Peri-neural Dexmedetomidine<br>Patients in this group will receive 25 ml of 0.5% bupivacaine plus 1 ml (75microgram) Dexmedetomidine peri-neurally | Drug: peri-neural dexmedetomidine as adjuvant to bupivacaine in femoral nerve block<br>* ultrasound guided femoral nerve block with injection of 25 ml bupivacaine 0.5% perineurally with 1 ml dexmedetomidine 25, 50, or 75 microgram perineurally. After adequate assessment of femoral nerve block, patients will be transferred to the operating room to receive a standard general anesthesia.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| duration of sensory block | the time interval between the onset of the sensory block and the complete resolution of normal sensation. Over a period of 30 min after injection of the study medications and every 2 hours postoperatively till complete recovery of normal sensation; a blinded investigator will assess sensory block with pinprick test using a 3-point scale: 0 ═ complete loss of sensation, 1 ═ partial loss of sensation and 2 ═ normal sensation. Pinprick test will be done in comparison to the contralateral area at the sensory distribution of the femoral nerve. | Every 5 minutes for the first 30 minutes after end of study medications injection, then postoperatively every 2 hours till complete recovery of normal sensation. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time to first request of postoperative rescue analgesic | the time interval between the onset of successful sensory block and the first request to postoperative analgesia | over the first postoperative 24hours | 
| Onset of sensory block | the time elapsed between the end of injection and the development of complete sensory block | up to 30 minutes after the end of injection | 
| Onset of motor block | the time elapsed between the end of injection and the development of complete motor block | up to 30 minutes after the end of injection | 
| visual analogue pain scores (VAS) | Visual analogue pain scores (resting and dynamic VAS) will be assessed at 2, 4, 6, 8, 12, 16, and 24 hours postoperatively. | 2hours post operative and for 24hours | 
| Richmond Agitation-Sedation Score (RASS) | Richmond Agitation-Sedation Score (RASS) will be assessed at 2, 4, 6, 8, 12, 16, and 24 hours postoperatively. | 2hours post operative and for 24hours | 
| duration of motor block | The time interval between the onset of the motor block and the complete resolution of the motor power in quadriceps muscle. Over a period of 30 min after injection of the study medications and every 2 hours postoperatively till complete recovery of motor power; a blinded investigator will assess the motor block using a 3-point scale where: 0 ═ no movement, 1 ═ reduced motor strength, but some perceptible movement, and 2 ═ normal motor function. | Every 5 minutes for the first 30 minutes after end of study medications injection, then postoperatively every 2 hours till complete recovery of motor power. | 
| total morphine consumption | The total dose of morphine needed by the patient postoperatively till 24 hours. | The first 24 hours postoperatively | 
| perioperative hemodynamic parameters | Vital signs (heart rate and arterial blood pressure) will be recorded at 0, 15, 30 minutes after femoral nerve block, then every 10 minutes intraoperatively, and every 2 hours postoperative for a period of 12 hours. | will be recorded at 0, 15, 30 minutes after femoral nerve block, then every 10 minutes intraoperatively, and every 2 hours postoperative for a period of 12 hours. | 
| incidence of side effects. | Adverse events will be defined as hypotension (a 30% decrease in systolic blood pressure in relation to the baseline value), bradycardia (heart rate less than 60 beats per minute), desaturation (SpO2 < 90% on room air) and postoperative nausea and/or vomiting. | from the injection time till 24 hours postoperatively | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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femoral nerve block, peri-neural dexmedetomidine