NEED FOR THE STUDY:

            Peripheral nerve blocks not only provide intraoperative anaesthesia but also extend analgesia in the postoperative period without any systemic side effects.⁽¹⁾

            There has always been a search for adjuvants to the regional block with drugs that prolongs the duration of analgesia with lesser adverse effects.⁽¹⁾ Many drugs have been tried like opiods, clonidine, hyaluronidase, dexamethasone, midazolam.⁽⁷⁾

            Alpha₂ adrenergic receptor agonists have been tried either alone or in combination with another drug to prolong anaesthesia in various methods of anaesthetic administration like epidural, intrathecal and regional nerve blocks.⁽¹⁾ Dexmedetomidine is an α₂ receptor agonist and its α _2/α₁ selectivity is 8 times more than clonidine.² Several studies have found dexmedetomidine to be safe and effective in various neuraxial and regional anaesthesia in humans including intrathecal and IV regional anaesthesia with lesser side effects.^(2,3)

            The aim of this study is to evaluate the effect of addition of dexmedetomidine to 0.25% bupivacaine in brachial plexus block.

REVIEW OF LITERATURE:

            Saritha et al, conducted a study in 2012 and reported that Dexmedetomidine when added to local anaesthetics in supraclavicular brachial plexus block enhanced the duration of sensory and motor block and also duration of analgesia. It also enhanced the quality of block as compared with clonidine.⁽¹⁾

           Aliye maoglu et al conducted double a blind randomized controlled study on 60 patients in 2010 and reported that dexmedetomidine added to levobupivacaine for axillary brachial plexus block shortens the onset time and prolongs the duration of block and duration of postoperative analgesia.⁽²⁾

                Rachana Gandhi et al conducted a prospective double blind study in 2012 and reported that when dexmedetomidine added to bupivacaine have better hemodynamic stability and greater postoperative analgesia as compared to only bupivacaine used in brachial plexus block.⁽³⁾

               Amany S.Ammar et al in their study on brachial plexus block reported that addition of dexmedetomidine to bupivacaine during brachial plexus block provides enhancement of onset and motor blockade, prolonged duration of analgesia, increases duration of sensory and motor block, yields lower verbal response scale pain scores and reduces supplemental opiod requirements.⁽⁴⁾

                Rutkowska et al conducted a study in 2009 on intravenous dexmedetomidine on brachial plexus block in patients with end stage renal disease and showed added dexmedetomidine prolongs the duration of brachial plexus block.⁽⁵⁾

            A. Duma  et al conducted a prospective randomised controlled double blind trial in 2005 and reported that adding clonidine to bupivacaine or levobupivaaine in brachial plexus block significantly increases the duration of block.⁽⁶⁾

            Esmaoglu et al conducted study in 2005 and reported that addition of dexmedetomidine  to lidocaine during intravenous regional anaesthesia improves the quality of anaesthesia and intraoperative as well postoperative analgesia without side effects.⁽⁷⁾

                Koj Jarbo  et al in their study in 2005 has shown that adding midazolam to bupivacaine hastened onset of sensory and motor block and improved postoperative analgesia when used in brachial plexus block.⁽⁸⁾

            Bazin et al reported sustained analgesic effect from opiods(sufentanil) used in supraclavicular brachial plexus block compared with saline.⁽⁹⁾

OBJECTIVES OF THE STUDY:

1.To study the effects of 0.25% bupivacaine with dexmedetomodine in brachial plexus block

2.To study the effects of 0.25% bupivacaine in brachial plexus block

3.To compare the effects of 0.25% bupivaciane with dexmedetomidine and 0.25% bupivaciane alone in brachial plexus block

MATERIAL  AND METHODS

      SOURCE OF DATA :

    Patients posted for elective orthopaedic surgeries on the upper limb admitted in Father Muller Medical College Hospital from August 2012 to July 2014.

7.2 METHOD OF COLLECTION OF DATA:

Study type: Prospective Randomised, Double blind study

Duration of study: Two years

Sample size: 60 patients selected using purposive sampling technique

INCLUSION CRITERIA:

            Patients for  orthopaedic surgeries on upper limbs:-

    1. ASA(American Society of Anaesthesiologists) grade 1 and 11

    2. between the ages of 18-60years, of either sex

    3. Undergoing orthopaedic surgeries on upper limb

  EXCLUSION CRITERIA:

       Patients with:-

    1. Patients on adrenoreceptor agonist and antagonist therapy

    2. Known hypersensitivity to local anaesthetics

    3. Uncontrolled diabetes milletus

    4. Pregnant woman

    5. Preexisting peripheral neuropathy

    6.Patients with bleeding disorder      

 7. ASA 111 and above                                                                                                                                        

METHODOLOGY:

        After approval of institutional ethical committee, 60 consenting patients fulfilling the inclusion criteria will be considered for our study. A pre-anesthetic checkup will be done for all patients which will include a detailed history, general physical and systemic examination. Basic investigations will be done (Hb%, complete blood counts, bleeding time, Clotting time, random blood sugar, serum urea, serum creatinine, if age is above 45yrs then ECG). Patients will be kept nil per oral overnight.

     Selected patients will be divided randomly into two groups using “slips in a box technique” of 30 each, with

 GROUP A:34ml of 0.25% Bupivacaine with 0.5ml(50µg) dexmedetomidine

 GROUP B:34ml of  0.25% Bupivacaine with 0.5ml 0.9% saline

     On arrival in the operating room, baseline heart rate, blood pressure and oxygen saturation will be recorded. An intravenous line will be secured in the unaffected limb and ringer lactate will be started. All the patients will be receiving brachial plexus block through the supraclavicular approach by an experienced anaesthesiologist different from the one assessing the patient intra and postoperatively. Both will be blinded to the treatment groups.

     Neural localization will be achieved using nerve stimulator, following negative aspiration, the solution containing local anaesthetic combined with dexmedetomidine or normal saline as mentioned above will be injected.

    Sensory block will be assessed by pinprick test using 3-point scale

Motor blockade will be done using Bromage three point score

      Sensory and motor blocks will be evaluated every 3 minutes until 30minutes after injection.

       Onset time of sensory block defined as the time interval between the end of total local anaesthetic administration and complete sensory block. Duration of sensory block was defined as the time interval between end of local anaesthetic administration and complete resolution of anaesthesia on all nerves.

            Onset of motor block defined as the time interval between the end of local anaesthetic administration and complete motor block. Duration of motor block is defined as time interval between end of local anaesthetic administration and complete resolution of motor block.

       Heart rate, systolic blood pressure(SBP), diastolic blood pressure(DBP) and saturation of oxygen(SpO₂) will be recorded at 0 minutes,5 minutes,10 minutes,15 minutes,30 minutes,45 minutes,60 minutes,90 minutes and 120 minutes. Adverse events like hypotension (20% decrease in relation to baseline) and bradycardia (heart rate <50 beats per minute) will be corrected with appropriate measures. Duration of motor and sensory blockade after surgery will be recorded.

    Rescue analgesia diclofenac sodium 75mg IM will be given when patient visual analogue score >5.

0-      No pain

10- worst possible pain

STATISTICAL ANALYSIS:

Collected data will be analysed by ANOVA (analysis of variance) for repeated measures Chi-square test and Unpaired T-test.