Comparison of Success Rate of the Classic Subclavian Perivascular approach with the Lower Interscalene approach of Supraclavicular Brachial Plexus block for upper limb surgeries- A Randomised Controlled Trial

ï‚· After approval by the Institutional Scientific and Ethical Committee, and CTRI approval this

prospective, randomised and observer-blinded study will be done on n patients undergoing

elective upper limb surgeries of the elbow, forearm and hand in a tertiary medical college

hospital.

ï‚· The patients will be randomized to receive either Supraclavicular(Group S) or lower

Interscalene(Group I) blocks by computer-generated random numbers and closed-envelope

method.

ï‚· All the patients will be pre-medicated with Tab Alprazolam 0.5 mg orally before shifting to

the operation theatre. A Randomisation envelope will be opened at this stage and the patient

allocated to either Group I or S.

ï‚· All the blocks will be performed by the anaesthesiologist with experience of performing 10-

30 blocks using both ultrasound and nerve stimulator under the supervision of an experienced

anaesthesiologist and will not take no further part in that case management.

ï‚· All the blocks will be performed with 25 mL 0.5% Ropivacaine and 50mcg Dexmetomidine.

Nerve Stimulator – STIMPOD NMS450, XAVANT Technology, model no XT-45021; B

Braun 50mm stimuplex needle

ï‚· The second anaesthesiologist who will be blinded to the type of block given will monitor all

the study parameters and decide on further management of the patient.

GROUP S

ï‚· The supraclavicular block will be performed with the patient in supine position and the head

tilted to the opposite side, and the skin will be disinfected and draped.

ï‚· In this group, the positive electrode from the peripheral nerve stimulator (PNS) is attached to

an ECG lead and placed on the ipsilateral arm, and the negative electrode is attached to the

50mm stimuplex needle. After skin preparation, the subclavian artery is palpated in the

supraclavicular region and skin is infiltrated with 2% lignocaine immediately lateral to the

artery. The point of needle entrance is about one inch lateral to the artery. The needle is

inserted through the skin in a downward, inward and posterior direction with the PNS set to

deliver 1mA current at 1 Hz frequency and 0.1 ms of pulse duration. The needle is slowly

advanced until muscle twitch (elbow/wrist/ finger flexion/extension) is obtained. Once the

finger twitch is obtained, the current is gradually reduced to 0.4 mA and then the local

anaesthetic solution is injected after negative aspiration. If muscle twitch is present even at

0.2mA , it indicates that the needle is inside the nerve sheath.

GROUP I

ï‚· The lower interscalene block will be performed with the patient in supine position and the

head tilted to the opposite side, and the skin will be disinfected and draped.

ï‚· In this group, the positive electrode from the PNS is attached to an ECG lead and placed in

the ipsilateral shoulder, and the negative electrode is attached to a 50mm stimuplex needle.

ï‚· For LISB, the distance between C6 and the clavicle is divided into 3 equal parts. Skin is

infiltrated with 2% lignocaine and the needle inserted at two-thirds of this distance caudally

from C6.

ï‚· The needle is inserted at the lowest point on the interscalene groove in a downward, inward

and posterior direction with the PNS set to deliver 1mA current at 1 Hz frequency and 0.1 ms

of pulse duration.

ï‚· The needle is slowly advanced until muscle twitch (elbow/wrist/ finger flexion/extension ) is

obtained. Once the finger twitch is obtained, the current is gradually reduced to 0.5 mA and

then the local anaesthetic solution is injected after negative aspiration. If muscle twitch is

present even at 0.2mA , it indicates that the needle is inside the nerve sheath.

Sensory evaluation for pain and touch will be done for the entire cutaneous innervation of upper

limb,( 5 nerves)i.e., musculocutaneous, radial, ulnar, median, medial cutaneous nerves of forearm.

The sensory block in each dermatome will be evaluated using the following scale:

• 2 – normal sensation

• 1 – hypoesthesia

• 0 – no sensation felt

Motor block will be assessed after injection of the drug according to modified Bromage scale for

upper extremities. Flexion, extension, abduction will be checked at the elbow, wrist, and fingers.

Modified Bromage grade to assess upper limb motor weakness:

• Grade 0: Normal motor function with full extension of elbow, wrist, and fingers

• Grade 1: Ability to flex and extend wrist and fingers

• Grade 2: Ability to flex and extend only fingers

• Grade 3: Complete motor block with the inability to move elbow, wrist, and finger.

The onset and degree of sensory and motor block will be observed every 5 min for 30 min till

complete blockade is achieved.