On arrival of the patients to regional anesthesia room, patients will be secured with
20-gauge intravenous cannula. Monitoring will include ECG, non-invasive arterial blood
pressure, and pulse oximetry (SpO2).
Before receiving supraclavicular brachial plexus block, patients will be randomly
assigned into one of the two study groups:
MS-SCBPB Group (n=22): this group will receive ultrasound-guided supraclavicular brachial
plexus block with total volume 20 mL bupivacaine 0.20% and 8 mg dexamethasone.
SCBPB Group (n=22): this group will receive ultrasound-guided supraclavicular brachial
plexus block with total volume 20 mL bupivacaine 0.5% and 8 mg dexamethasone.
Another doctor not involved in the block procedure will evaluate the patients
postoperative.
Technique of SCBPB:
The technique of ultrasound-guided supraclavicular brachial plexus block will be
performed with the patient in semi-sitting position with head tilted to the opposite side
of injection site. A linear ultrasound probe (4-12MHz) will be placed parallel to the
clavicle in the supraclavicular fossa visualizing the subclavian artery is seen beating
above the first rib. A volume of 2 mL lignocaine 2% will be infiltrated subcutaneous
before the block. A 20-gauge needle will be advanced in plane under direct vision aiming
to the corner pocket towards the deeper portion of the brachial plexus at the angle
between the first rib and the subclavian artery, a total of 10 mL of drug will be
injected, aspirating every 5 ml. Then, the needle will be retracted and advanced at a
shallower angle, aiming toward the superficial brachial plexus after negative aspiration,
10 mL of drug will be injected, aspirating every 5 ml.
Block assessment:
Time needed for surgical block: the time interval from the end of ultrasound guided
supraclavicular brachial plexus block injection till achievement surgical anesthesia
Assessment of surgical anesthesia using a 3-point score:
Extent of sensory block:
In all four nerves: hypothenar eminence (ulnar nerve), thenar eminence (median nerve),
dorsum of hand (radial nerve), and lateral aspect of the forearm (musculocutaneous nerve)
0 = loss of sensation to light touch, 1 = loss of sensation to pinprick, 2 = normal
sensation
Extent of motor block:
In all four nerves: thumb adduction (ulnar nerve), thumb opposition (median nerve), thumb
abduction (radial nerve), and flexion of the elbow in supination and pronation
(musculocutaneous nerve) 0 = no movement, 1 = paresis, 2 = normal movement Interpretation
: Block success for surgical anesthesia is defined as the achievement of sensory and or
motor scores of 1 or less at 5, 10, 15, 20, and 30 minutes post-injection.
Intraoperative Care:
An anesthesiologist blinded to group allocation will be attending for monitored
anesthesia care with a safe conscious sedation intraoperatively, titrated to patient
comfort using low intravenous doses of midazolam (1-3mg), fentanyl (1-2 μg/kg), and/or
Propofol (25-75 μg/kg/min). In the event of failed block, it will be managed with either
local anesthetic supplementation at the corresponding spared nerve or converted to
general anesthesia.
Postoperatively, all patients will receive 1 g paracetamol every 6 h and 30 mg ketorolac
every 12 h. Intravenous morphine titration will be carried out at patient wake-up to
achieve pain control (Using visual analogue scale (VAS) for pain assessment from 0 the
Best to 10 the worst) by an attending anesthesiologist blinded to group allocation.
Patients with a VAS score of ≥ 4 and patients who will request rescue analgesia will be
treated with IV morphine in 2 mg increments every 4 hours with upper limit for the total
administered dose (maximum 20 mg per day). If the patient appeared sedated (Ramsay
sedation scale > 2), and/or severe morphine-related side effects are encountered
including respiratory depression (Spo2 < 95% and/or RR < 12 breaths/min), allergic
reaction, hypotension, or severe pruritus, morphine titration will be stopped and the
patient will be excluded from the study.