http://www.iosrjournals.org/iosr-jdms/papers/Vol4-issue3/G0433039.pdf
I looked at this study. They showed buprenorphine and clonidine prologmbgung the block conpared to bupiv alone, but... The mean duration of analgesia for bupiv 0.25% 40cc supraclav block was like 180min = 3h. That's pathetic. I still want to try buprenorphine but these results are weird.
Look what I found for you:
Title Is there a Dosage Effect of Dexamethasone as an Adjuvant for Brachial Plexus Nerve Block? - A Prospective Randomized Double-blinded Clinical Study
Speaker: Jiabin J. Liu
Author: Jiabin Liu, M.D., Kenneth A. Richman, M.D., Nabil Elkassabany, M.D.
Affiliation: Anesthesiology and Critical Care, The University of Pennsylvania, Philadelphia, PA, USA
Session: Moderated E-Poster Session 5
Date: Saturday - May 04, 2013 08:15-09:45
Location: ePoster Area
Subtopic: Regional Anesthesia
Topic: Scientific Abstracts
Introduction: Brachial plexus block is a great option for postoperative pain management after shoulder arthroscopy. Dexamethasone, as an adjuvant, to local anesthetics further expanded our capability to provide longer duration of analgesia with a single shot nerve block. Recent evidence showed that that 8mg of preservative-free dexamethasone has been able to prolong the analgesia duration of brachial plexus nerve block by 50 to 100 percent. There is only one study with reduced dosage of dexamethasone of 4mg by Dr. Nader´s group. The authors observed decreased analgesia duration from 25.2 to 21.6 hours, while not statistic significant.
The safety of adding dexamethasone and the implication to the incidence of neuronal damage are still in question. Available studies failed to draw any definitive conclusion about the safety of adding dexamethasone because of the limited number of the studies and the small sample size in each. It is appealing that lower dose of dexamethasone may be clinically effective with decreased risks. We hypothesize that dexamethasone as an adjuvant to local anesthetic has dose response effects in regards to the duration of sensory and motor nerve blocks.
Methods: The study was reviewed and approved by the institutional review board of the University of Pennsylvania. We proposed to recruit 100 outpatient patients undergoing shoulder arthroscopic surgery between the age of 18 to 70 with ASA I-III physical status. All patients will receive general anesthesia and an ultrasound guided supraclavicular brachial plexus nerve block with 30ml of 0.25% bupivacaine. All patients will be randomly assigned into one of four groups: control group, 1mg dexamethasone, 2mg dexamethasone, or 4mg dexamethasone in addition to 0.25% bupivacaine. All patients will be interviewed over the phone on post-operative day 1, day 2, and day 7. The recovery of sensory, motor, time to first opioid requirement, and opioid consumptions will be recorded. All data will be analyzed via ANOVA.
Results: Currently, we have recruited over 40 patients into the study. Preliminary data analysis showed that duration of analgesia was significantly prolonged in all groups received dexamethasone.
The average analgesia duration of plain 0.25% bupivacaine was 15.7 hours, while average analgesia durations were 22.4, 23.4, and 22.2 hours for dexamethasone 1mg, 2mg, or 4mg group respectively. The average durations of motor block showed similar trend.
Discussion:
Our preliminary data analysis showed no dose response effect of dexamethasone as an adjuvant to local anesthetic for brachial plexus nerve block. The addition of dexamethasone to bupivacaine significantly prolonged the duration of sensory and motor nerve block. In addition, our preliminary finding indicated shorter motor block duration than sensory block. We are currently actively recruiting additional patients into this study.