Perineural Low-dose Dexamethasone Added to Infraclavicular Block Anesthesia

Overview

Dexamethasone has an evidence-based indication in postoperative emesis prophylaxy and as a antiinflammatory steroid. Although the perineural administration is off-label, several studies recognised its analgetic action as an adjuvant for peripheral nerves blockade, permitting to reduce the concentration of the local anesthetics and extending the sensory and motor block.Questions remain concerning the mechanism of action, optimal dose, the lack/degree of toxicity and the comparison with intravenous administration.The aim of this prospective randomized controlled study is to investigate the efficacy of analgesia with 4 mg or 2 mg Dexamethasone added to a combination of ropivacaine 0,5% and lidocaine 1% in vertical infraclavicular blockade (VIB) anesthesia for upper limb surgery.

The investigators conducted a prospective randomized controlled study in 150 patients American Society of Anesthesiologists (ASA) score I-III scheduled for upper limb surgery , divided in 3 groups: group A received anesthesia VIB block with ropivacaine 0,5% 100 mg +lidocaine 1%+1 ml saline; group B received VIB block with ropivacaine 0,5% 100 mg +lidocaine 1% + 2 mg dexamethasone; group C received ropivacaine 0,5% 100 mg +lidocaine 1% + 4 mg dexamethasone.The anesthesiologist may use the ultrasound for visual guidance, but should also use the nerve stimulator in order to maintain the homogeneity of the procedure. Intraoperative sedation was provided with intermittent bolus 10-20 mg IV Propofol. Postoperatively all patients received the same analgetic protocol when Visual Analog Pain Scale (VAS) over 3 with IV Perfalgan and Lornoxicam 8 mg/12 hours for 24 hours. If after 30 minutes VAS is still over 3, a loading dose of morphine 0,05 mg/kg should be administered. At first analgetic request, the nurse conducts an ice-probe test to both arms and will note the answer: same cold, slightly burn, burn, aching with the reason to test the potentially hyperalgesia effect related to ropivacaine. The data recorded are: time to first analgetic use, VAS at block regression, ice-probe test, motor and sensitive block duration, glycemic variations at 4 h, neurological complications immediately after block, total morphine consumption.