Midazolam in Supraclavicular Brachial Plexus Block

• Status: Completed
• Trial end date: 2018-09-01
• Target enrollment: 0
• Participant gender: All

Summary

An effective brachial plexus block (BPB) provides a useful alternative to general anesthesia for upper arm surgery producing complete muscular relaxation. It provides surgical anesthesia in upper extremity surgery, post-operative analgesia and chronic pain management. In addition to surgical procedure on conscious patients and early eating after the procedure make regional anesthesia more attractive.

Brachial plexus block also maintains stable intraoperative hemodynamic and associated sympathetic block. The sympathetic block decreases postoperative pain, vasospasm and edema. The nerve of brachial plexus may be blocked anywhere along its course. The approach for blocking brachial plexus nerve is interscalene, supraclavicular, infraclavicular and axillary approach.

Supraclavicular approach for blockade of the brachial plexus is the most commonly used approach in providing surgical anesthesia. In recent years, the technique has gained importance as regional anesthetic technique for surgical, diagnostic and therapeutic purposes in interventional pain management. It includes blocking of the brachial plexus where it is most compactly arranged, with fewer requirements of the anesthetic solution and rapid onset of action. Supraclavicular nerve block is technically easy to perform because of reliable and fixed landmark but association of pneumothorax is a profound complication.

The extent of blockade following injection into the sheath surrounding the brachial plexus may depend on the volume and concentration of local anesthetic (LA) used. Because of bupivacaine long duration of action, it is used most frequently among local anesthetics for BPB.

Inevitably, the effects of single-injection BPB dissipate after several hours unmasking the moderate-to-severe pain of the surgical insult. Efforts to prolong BPB duration by increasing LA dose are limited by their narrow therapeutic window and indeed may not be effective as recent studies have demonstrated equivalent analgesic duration with volumes as low as 5 ml.

Midazolam is known to produce antinociception and potentiate the effect of LA when given in neuraxial block. It produces this effect by its action on Gamma Aminobutyric Acid-A (GABA-A) receptors and also on the peripheral nerves which contain these receptors.

Several studies showed midazolam to be effective when used in intrathecal, epidural and caudal blocks and now recently midazolam with bupivacaine has been found to improve analgesic characteristics in peripheral blocks compared to bupivacaine alone. Due to the high blood concentration of benzodiazepine through conventional routes and profound sedation, proper assessment of analgesic effect was difficult to obtain. With the advent of the less toxic water soluble benzodiazepine (midazolam), it became possible to use it directly over the nerve tissues.

• Phase: Phase 2
• Accepts Healthy Volunteers?: No

Details

• Lead Sponsor: Assiut University
• Treatments: Bupivacaine; Midazolam

Criteria

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.