Conditions: Local Anesthetic
Keywords: surgery for arm hand or elbow mepivacaine ropivacaine hand surgery elbow surgery forearm surgery
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 103
Healthy volunteers: no

Brief summary:
This study will test the hypothesis that sequential injection of 1.5% mepivacaine followed 90 seconds later by 0.5% ropivacaine in ultrasound guided supraclavicular block provides a quicker onset and a longer duration of analgesia than an equi-dose mixture of the two local anesthetics.

Detailed description:
Patients will be randomized into one of two groups, Group M: Ropivacaine and Mepivacaine - subject will receive two injections before surgery begins. These two injections will consist of the mixture of mepivacaine (15 ml) and ropivacaine (15 ml).

Group S: Mepivacaine followed by Ropivacaine. Subjects will receive two injections before surgery begins. One injection will contain mepivacaine (15 ml) and the other will contain ropivacaine (15 ml).

On the first, second, and third mornings after surgery,subjects will be asked to rate their pain on a scale of 1 to 10. If the subject is discharged from the hospital, a telephone call will be made to the subject's home to collect this information.

Arms:
arm 1: combined group: ropivacaine and mepivacaine mixture: 1:1 volume mixture of 1.5% mepivacaine and 0.5% ropivacaine in 2 syringes (labeled 1 and 2) with 15 mL in each (total, 30 mL) injected in immediate sequence; arm 2: sequential group: mepivacaine followed by ropivacaine: syringe 1 containing 15 mL of 1.5% mepivacaine, syringe 2 containing 15 mL of 0.5% ropivacaine (total, 30 mL); syringe 2 was injected with a 90-sec delay after injection of syringe 1.

Interventions: intervention 1: Ropivacaine intervention 2: Mepivacaine
Intervention descriptions: intervention 1: ropivacaine (15 ml). intervention 2: One syringe will contain mepivacaine (15 ml)

Protocol document: