Tramadol sparing effect of dexmedetomidine as an adjuvant in preoperative stellate ganglion block in patients undergoing upper limb surgeries

In recent years greater emphasis is being laid on the management of post operative pain relief..Peripheral nerve blocks for upper limb surgeries have shown to provide better outcome in terms of pain relief and patient statisfaction .Peripheral nerve blocks are also associated with enhanced participation of patients in rehabilitation phase thus reducing hospital cost and stay.Role of autonomic nervous system in control of chronic pain has been described in literature in patients of complex regional pain syndrome. Mc Donell et al have demonstrated the role of autonomic nervous system in management of acute post operative pain .In his case series preoperative stellate ganglion block was given to patients undergoing operative treatment for humerus fractures and effective postoperative analgesia was reported upto 48 hours.Further a recent randomised control trial conducted by Kumar et al demonstrated a postoperative tramadol sparing effect following preoperative stellate ganglion in patients undergoing upper limb orthopaedic surgery under general anaesthesia.The role of stellate ganglion block in postoperative pain relief has now been establised for upper limb surgeries.Literature describes the role of various adjuvants to peripheral nerve blocks .As most patients report increased pain during night hours when access to care is limited adjuvants have been used to increase duration of pain relief as well as requirement of analgesic medication postoperatively.Dexmedetomidine is an alpha 2 agonist having both sedative and analgesic properties. Use of dexmedetomidine  in various nerve blocks as an adjuvant and also in cervical plexsus block has shown to shorten the sensory block  onset time and extended the duration of analgesia.A through search of literature did not reveal any study using dexmedetomidine as an adjuvant with local anaesthetic in stellate ganglion block .We hypothesise that the addition of dexmedetomidine to lignocaine during preoperative ultrasound guided stellate ganglion block will have no effect on postoperative cumulative tramadol consumption at 48 hours in patients scheduled for upper limb surgeries under general anaesthesia.

**Sample size calculation-**As per a pilot study conducted for tramadol sparing effect of preoperative stellate ganglion block for postoperative pain relief in patients undergoing upper limb surgeries the mean tramadol consumption came out to be 130 mg with standard deviation of 14.1.To estimate a difference of consumption of 10 % tramadol our sample size came out to be 15 patients per group ,with a power of 80% and confidence interval of 95%.Considering a drop out rate of 20 % the sample size came out to be 18 patients in each group.

**Primary outcome-**To study tramadol sparing effect of dexmedetomidine as an adjuvant with lignocaine in preoperative stellate ganglion block for postoperative pain relief following upper limb surgeries.

Secondary outcome-To study perioperative pain relief ,haemodynamics  and adverse effects of preoperative stellate ganglion block in patients scheduled for upper limb surgeries.

Result : The cumulative tramadol consumption at the end of 48 hours (p=0.01) was significantly reduced in the group I as compared to group II . In group I postoperative vas at rest was significantly reduced up to n12 hours potoperatively as compared to group II (p= 0.05). the cumulative tramadol consumpotion was not reduced significantly in group III compared to group II (p=0.51).