Control of Tourniquet Pain With an Axillary Ring of Subcutaneous Local Anesthetic

Study Summary

Purpose: Even with excellent regional anesthesia of the upper extremity, tourniquet (Tq) pain from an upper arm Tq can limit the ability to use regional anesthesia as the primary anesthetic for surgical procedures on the upper extremity. The aim of this study is to determine whether a subcutaneous ring of local anesthetic on the inner aspect of the upper arm just distal to axillary crease will significantly diminish Tq pain. If it does, peripheral nerve blocks distal to the Tq (i.e., nerve blocks at the elbow) could be used as the primary anesthetic for surgery of the hand and forearm. These distal peripheral nerve blocks have fewer complications than brachial plexus blocks performed at higher levels, and, postoperatively, the patient has better control of his or her arm when distal nerve blocks are used. Procedures (methods): This is a prospective, cross-over study to examine the effectiveness of an upper arm Subcutaneous ring of local anesthetic alone in relieving Tq pain. This Subcutaneous ring of local anesthetic is often referred to as "Intercostobrachial nerve block" or "Subcutaneous ring anesthesia (SRA)." Twenty volunteers will be randomized into four groups of 5 participants each. During the initial experiment, the first group will be given SRA with 10-15 mL of 0.25% Bupivacaine with Epinephrine 1:200,000 on their dominant arm, the second group will be given SRA with 10-15 mL of 0.25% Bupivacaine with Epinephrine 1:200,000 on their non-dominant arm, the third group will be given "sham" SRA with saline on their dominant arm, and the fourth group will be given "sham" SRA with saline on their non-dominant arm. 15 minutes after SRA, a Tq will be applied to the arm with the subcutaneous injection and it will be inflated to 100 mm Hg above the subject's baseline systolic blood pressure. We will monitor heart rate, blood pressure (opposite arm) and pain (0 to 10 VAS) every 5 minutes. Each Tq will be released when the subject requests deflation or when 1 hour of T

Primary Outcome

15 minutes after either Bupivacaine or placebo injection, Tq was inflated to 100 mm Hg over subjects systolic blood pressure. When the subject found the Tq too uncomfortable, the Tq was deflated and the time documented. Approximately one month later, each subject had the opposite injection of either placebo or Bupivacaine on the same arm, and the duration of Tq inflation was again measured. Due to a strong crossover effect, only the data assessed from the first intervention was analyzed.

Conditions Studied

Interventions

• DRUG Normal Saline
• DRUG Bupivacaine with Epinephrine

Study Locations (1)