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

Phase 4CompletedNCT02089932

Cairo University60 enrolled

Overview

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.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

SUPPORTIVE_CARE

Masking

QUADRUPLE

Enrollment

Conditions

Dexmedetomidine Femoral Nerve Block Arthroscopic Knee Surgery

Interventions

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.

Eligibility

Sex: ALLMin age: 15 YearsMax age: 45 Years

Medical Language ↔ Plain English

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

Outcomes

Primary Outcomes

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.

Time frame: 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 Outcomes

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

Time frame: over the first postoperative 24hours

Onset of sensory block

the time elapsed between the end of injection and the development of complete sensory block

Time frame: 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

Time frame: 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.

Time frame: 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.

Time frame: 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.

Time frame: 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.

Time frame: 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.

Time frame: 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.

Time frame: from the injection time till 24 hours postoperatively