Comparative study of bupivacaine and levobupivacaine with adjuvant buprenorphine in ultrasound guided supraclavicular brachial plexus block in upper limb surgeries

Informed and written consent will be taken from 60 patients satisfying the inclusion criteria who will be undergoing upper limb surgery in JSS hospital, Mysuru.

A thorough preanesthetic evaluation will be done 24 hours prior to the procedure.

Standard preanaesthetic advice of fasting will be given to the patient. The patients were informed about the procedure and its potential consequences. All the patients were taught how to use the visual analog scale system. Standard preanesthetic advice of fasting will be given to the patient. Randomization will be done by the sequentially numbered, opaque, sealed envelope (SNOSE) technique by experienced anesthesiologist performing the block. The enrolled 60 patients based on randomization will be divided into two groups.

Group BB – 30 patients will receive 30ml of 0.5% bupivacaine with 150 mcg of buprenorphine

Group LB –30 patients will receive 30ml of 0.5% levobupivacaine with 150mcg of buprenorphine

On the day of the procedure, PAE will be reviewed and any fresh clinical history or signs along with relevant investigations will be noted. Fasting status and the site of surgery will be confirmed. After shifting to operation theatre, necessary monitors like electrocardiogram (ECG), pulse rate, oxygen saturation, blood pressure, respiratory rate will be connected and basal parameters noted.  An intravenous (IV) cannula will be inserted in the adjacent nonoperative arm and IV infusion of Ringer’s Lactate will be started. Premedication will be done with IV midazolam 0.03-0.04g/kg was given and oxygen will be administered at 4L/min through a Hudson’s mask. Ultrasound (placed on the opposite side of the block) with linear probe, a pre block scan will be done to assess the anatomy and location of the nerves and its relation to the vessels with the use of color Doppler

Under aseptic precautions, area of injection is cleaned with antiseptic solution and ultrasound probe is covered with sterile wrap. Patient will be in supine position and head is turned to the opposite side of the block. The head of the bed may be elevated about 30 degrees. A towel roll may be needed under ipsilateral shoulder to improve access to supraclavicular space. The anesthesiologist performing the block will be positioned comfortably on the same side as the block. After applying sufficient jelly on the US probe, it is placed on the supraclavicular fossa in the transverse orientation parallel to the clavicle and aimed inferior to the ipsilateral thorax to identify the subclavian artery and the lateral location of the supraclavicular portion of the brachial plexus. Local infiltration is done with 2-3ml of 2% lignocaine at the injection site. In plane approach of needle placement is used to locate and all drug depositions are done under direction vision of the needle after confirming negative for aspiration of blood. In group I, 30 ml of 0.5% bupivacaine+ 150mcg buprenorphine is injected all around the plexus. In group II 30ml of 0.5% levobupivacaine + 150 mcg buprenorphine is injected into the supraclavicular nerve region. Block failure is described as the need for rescue analgesia i.e. sedative doses of fentanyl or other analgesics or conversion to general anesthesia.

For the first 30minutes, vital indicators (pulse rate, blood pressure, respiratory rate) will be measured every 5 minutes, then every 15 minutes till the end of operation, until the patient complained of pain corresponding to a VAS score of 4. The onset of sensory and motor blockade, the duration of sensory and motor block and duration of postoperative analgesia, time to first rescue analgesic will be recorded. Sensory block will be measured by loss of feeling to pinprick sensation over the C5-T1 dermatomes using Hollmen Scale as:

1. Normal sensation of pinprick

2. Pinprick felt as sharp pointed but weaker compared with same area in the other upper limb

3. Pinprick recognized has touch with blunt object

4. No perception of pinprick

The onset time of sensory block will be taken has the time interval in minutes from injection of the local anesthetic till a Hollmen score of 2, while the time for complete sensory block will be taken till a Hollmen score of 4. The total duration of sensory block will be taken as the duration of time in minutes from the time of complete sensory block till the time Hollmen score of less than 4 was reached.

Motor block will be assessed using a modified Bromage Score for upper extremity:

1. Normal motor function with full flexion and extension of elbow, wrist and fingers

2. Decreased motor strength with ability to move the fingers only

3. Complete motor block with inability to move the fingers

4. Unable to move the arm, elbow or fingers

Onset of motor block will be considered has the time interval in minutes from injection of the local anesthetic till when there was Grade-4 motor block. The total duration of motor block will be taken as the duration of time in minutes between the time to complete motor block till normal motor function (Grade 1). Pain will be assessed using VAS in which a score of 0 indicates no pain and a score of 10 indicates worst pain. The VAS measurements will be obtained at 2,4,6,12 hours post operatively. Rescue analgesic will be given at VAS score of 4. Time to first rescue analgesic and total analgesic given to each patient during first 24 hours’ post-operative period will be recorded. The occurrence of adverse effect like hypotension, nausea and vomiting will also be recorded