Midazolam in Supraclavicular Brachial Plexus Block

The day prior to surgery, all patients will undergo pre-anesthetic checkup including detailed history, thorough general, physical, systemic examination and weight of the patient. All patients will be kept nil by mouth for at least 6 hours.

• Written consent, coagulation profile, intravenous line, emergency resuscitation equipments including airway devices, advanced cardiac life support drugs for LA toxicity will be available.
• Patients will be monitored using standard monitoring (ECG, non-invasive blood pressure and pulsoximetry)
• All patients will be lightly sedated with 1 mg midazolam I.V. SonoAce 6 ultrasound machine with high frequency linear probe will be used in our study.

Palpation of the subclavian artery in the supraclvicular fossa, just lateral to the sternocledomastoid and above the clavicle (landmark located one finger or 1 cm above the clavicle at the junction of inner 2/3 and outer 1/3 of clavicle).

Position to perform supraclavicular BPB; the anesthetist will stand behind the patient's head, with the ultrasound machine on the side being blocked. The head of the bed is slightly raised to allow the shoulder to drop somewhat the patient's head will be turned to the opposite side, resting directly on the table without a pillow, the hand holding the probe will rest against the patient's jaw, the probe is placed in the supraclavicular fossa in a coronal oblique plane, the needle will be inserted from the lateral side, The pulsating hypoechoic supraclavicular artery is identified, lying above the hyperechoic first rib, the probe is then angled until both the first rib and the pleura are also seen simultaneously, The nerve structures (trunks or divisions) are usually visualized as a collection of hypoechoic round structures (a bunch of grapes) lying superior and postero-lateral to the subclavian artery. A 3 cm long 22 G needle with 10 cc syringe filled with respective LA agent will be inserted directing downward, forward and medially at the angle of 20° to the skin till the parasthesia elicited in the hand or the 1st rib hit, then the needle will be fixed at that point. After the negative aspiration respective agents will be given. A gentle massage over the area will be done with an idea of uniform spread. All brachial plexus injections will be administered slowly with repeated aspiration to prevent or detect early intravascular injection. The end of the injection will be considered time 0.

Inclusion criteria

• ASA I-II physical status patients.
• Age between 18 and 50 years.
• Patients planned for unilateral orthopedic forearm surgeries.

Exclusion criteria

• Patient refusal
• Any contraindication to regional block (i.e. coagulopathy, infection at the needle insertion site, contralateral pneumothorax or diaphragmatic paralysis)
• Bilateral limb surgery
• Pregnancy
• BMI >35
• Preexisting neuropathy involving the surgical limb
• Patients with any known contraindication to study medications
• History of a major psychiatric disorder.
• Chronic pain syndrome.
• History of substance abuse.
• Current opioid use.