Background and Aim: Many different routes have been introduced for prolonging the duration of axillary block in upper extremity procedures. In this study the effect of adding dexamethasone to lidocaine during axillary plexus block has been studied.

  Patients and Methods: This study was designed and performed as a double blind randomized clinical trial.The patients candidated for upper extremity procedures in Hazrat Fatemeh Hospital operation room, entered the study based on inclusive and exclusive criteria.The patients were divided in to two 30-person groups randomly. For axillary block in the first group (control or lidocaine group), a combination of 34cc lidocaine1.5 %, 2cc sodium bicarbonate and 2cc distilled water was used in the second group(dexamethasone group) the utilized solution was similar to that used in the first group but with 2cc of dexamethasone (8 mg) used instead of distilled water. The onset of sensory, motor and sympathetic block, duration of sensory and intensity of post operative pain was measured and recorded.The data was analysed with SPSS V.13.The quantitative data was displayed with mean and standard deviation. The qualitative data was displayed with frequency.The Chi square and t-tests were used for quality data quantity data, respectively.

  Results: The onset of sensory, motor and sympathetic block was similar in both groups and no significant statistical difference was present.The duration of the block and the time of the first request for analgesia post operatively were meaningfully longer in the dexamethasone group than lidocaine group(control group). Also the intensity of post operative pain from recovery to 6th hour after operation was meaningfully less in dexamethasone group than in control group.

  Conclusion: This study revealed that addition of dexamethasone to the combination of sodium bicarbonate and lidocaine for axillary plexus block can prolong the duration of block.Increase in the duration is more prominent for sensory than motor block. Meanwhile the post operative analgesia in this group was more than lidocaine group.