Comparative Evaluation of Fixed dose Dexmedetomidine and Esmolol Infusion as an Anaesthetic Adjuvant during Intracranial Surgery for Supratentorial Tumor: a double blind randomized study.

After  approval of institutional  ETHICScommittee, a  through pre anaestheticassessment will be done for every patient. After obtaining written informed consentfrom all the patients eligible for the study,  this randomized control trial will be conducted OT complex , departmentof neurosurgery, Bangur institute of neurology, institute of post graduatemedical education & research ( IPGMER).

 In this parallal group, randomized controltrial total  70 adults  patients, aged between 20-55 years , ASAphysical status I or II of either sex,preoperative GCS 14-15 scheduled forelective craniotomy for supratentorial tumour under general anaesthesia will betaken as subjects for the study. We will compare perioperative haemodynamicstability with dexmedetomidine  and  esmolol infusion in   two selective groups. The study populationwill be randomly allocated in two groups with the help of  computergenerated random number

( 1. D-GROUP –persons receiving Dexmedetomidineinfusion, 2.E-GROUP-persons receiving esmolol infusion).

 Simple balanced randamization will be onduted.All the drugs will be  prepared inidentical syringes by an independent anaesthesiologist who not involved in thisstudy   . Dexmedetomidine infusion will be prepared with 2 mldexmedetomidine ( 100µg/ml—total 200µg  )--mixed with 38 ml normal saline (total 40 ml- concentration 5 mcg/ ml). Esmolol infusion will be prepared with 20 mlundiluted Esmolol ( 10 mg/ml—total 200 mg)   .

All the patients will be premedicated with0.5 mg alprazolam at night day before surgery . Routine medications likeantiepileptic, will be continued as clinically indicated .  All puncture sites will be treated withtopical local anaesthetic cream . preoperative GCS was assessed for allpatients.Upon arrival in the preoperating room, preoperative consciousness andsedation were assessed by HUDES score  .Five lead surface electrocardiogram( ECG)  ,pulse oximetry , NIBP  were attached. A large bore i.v. canula wasinserted  and  intravenous(IV)  normal saline(NS) was started at rate of  100ml /hr. Under  local anaesthesia, A radial artery will becannulated for arterial pressure monitoring  . Baseline HR, MAP, SPO2 all  were measured before starting study druginfusion  as basal parameters. Both the study drug infusionwere started 20 mins[34]  before induction .

 Dexmeditomidine infusion  was startedand  continued at the rate of 1mcg/kg/hour wand esmolol infusion  wascontinued at the rate of 0.5 mg/kg/hour  for 20 min abefore induction[37].  .After 20 min study druginfusion, all the patients were shifted to operative room .Thereafter,dexmeditomidine  infusion was continuedat the rate of 0.2 mcg/kg/hr and esmolol is continued at 25 mcg /kg /min.Thestate of consciousness and haemodynamic parameters like  MAP,HR,SPO2  all were  recorded  again   (1-7) [38] just before induction.

  All the patients will bepre-oxyginated with 100% O2 by a face mask for 3 min and IV fentanyl( 2mcg/kg )was administered. The patient was induced with inj propofol infusion( 0.5 mg/kg/min)[39] and infusion will be continued until BIS SCORE reach below50.Time to reach BIS SCORE below 50 and total propofol requirement forinduction was noted. Neuromuscular block will be achieved by  requirement administering atracurium ( 0.5 mg/kg BW)and manual ventilation will be continued   for at least 3 minwith  100% oxygen. Laryngoscopy and intubationwill be performed when TOF 0.

   MAP,HR, SPO2 will be recorded just before andafter intubation and then at 1 min interval upto 5 min following intubation andthereafter ,at every 15 min intervals  till the end of operation.ETCO2  was maintained around 30-35 throughout theoperation.

 Skin will be infiltratedwith 2% lignocaine+adrenaline before surgical incision. Anaesthesia wasmaintained with  low flow air in oxygen(50:50—total 1 L/h). Propofol infusion was  continued throughout the operation after   at avariable  rate(25- 50 mcg/kg bw/ min) tomaintain BIS <50 [ 40 ]Neuromuscular block was maintained with  IV atracurium  0.1mg/kg as and when TOF >2  . [35]

. Hypertension (MAP>100) and tachycardia ( HR> 100)  willbe managed by injection fentanyl at 1 mcg/ kg bw for maximum consecutive twotimes at 15 min intervals, followed by  IV 10 mg propofol bolus, if not responded.Total intraoperative  propofol and fentanyl requirement were alsonoted.