Control of Tourniquet Pain With an Axillary Ring of Subcutaneous Local Anesthetic
Control of Tourniquet Pain With an Axillary Ring of Subcutaneous Local Anesthetic
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 Tq time has elapsed, whichever occurs first. The subject's discomfort level (VAS) just
 prior to deflation will be recorded. Since Tq pressure alone can inhibit nerve function, we
 will monitor motor and sensory function distal to the Tq every 10 minutes during Tq inflation
 and for 30 minutes after Tq deflation. One to two weeks after this initial study, the same 20
 subjects will receive SRA on the same arm and the same parameters will be measured. The 10
 subjects who received 0.25% Bupivacaine the first time will receive Normal Saline, and the 10
 subjects who received Normal Saline the first time will receive 0.25% Bupivacaine. In this
 way, each subject will act as his or her own control.
Inclusion Criteria: Volunteers will be eligible for the study if they meet all of the below
 criteria;

 -  American Society of Anesthesiologists (ASA) classification I or II

 -  18 years of age to a maximum of 70 years of age

 Exclusion criteria:

 -  Pre-existing parasthesia or neuropathy of any kind

 -  History of excessive alcohol consumption (> three drinks per night)

 -  Take analgesics on a regular basis

 -  History of any drug abuse

 -  Baseline systolic blood pressure ≥ 150

 -  Baseline diastolic blood pressure ≥ 85

 -  BMI ≥ 30 Pregnancy Allergic reaction to local anesthetic