Comparison of Dexmedetomidine versus Pentazocine-Promethazine for Tympanoplasty under Monitored Anesthesia Care: Randomized Double Blind study

All the patients will be undergo Pre-anaesthetic check-up including detailed history and clinical examination and investigations. The patients wil be counselled in detail about sedation, LA and operative procedure.The visual analogue scale (VAS)(0-10, where 0 indicated no pain while 10 indicated maximum pain) will be explained to the patients. Pre-operatively patients will be advised to remain nilby mouth for at least 8 hours for heavy fatty meal,6 hours for solid food, 2 hours for clear liquids. Patient will be shifted to operation theatre after confirming about fasting and consent. All baseline vital parameters; HR, SBP, DBP,MAP and SpO2 will be recorded by multi•para monitor. All the demographic variables will be recorded. Ringer lactate solution will be started after Intravenous(IV) access is secured. All eligible patients will be allocated in two groups randomly by block randomization. The anaesthesiologistconducting the case, patients and anaesthesiologist in the post anaesthesia care unit (PACU) were all blinded to group assignment. Blinded observer records the data and the anaesthesiologist who did not participate in patient management or data collection will be preparing the drug.

Group D :This group will receive nj. Dexmedetomidine 1mcg/kg in 10ml NS (normal saline ) over 10 minutes IV followed by it’s infusion at a rate of 0.2 mcg/kg/hr through infusion pump.

Group P : This group will receive a dose of inj.Pentazocine 0.6mg/kg and inj. Promethazine 0.5mg/kg IV in 10 ml NS over 10minutes followed by infusion of 0.2 mcg/kg/hr of NS through infusion pump.

The target end point of sedation will be aimed at maintaining a RSS 3 throughout the surgery.

LA anaesthesia will be administered by surgeon using 2% Lignocaine with Adrenaline (1:1,00,000) to block the greater auricular, lesser occipital, auriculotemporal nerves and four quadrants of the external auditory canal . After RSS of 3 was achieved 2% lignocaine and adrenaline (1:1,00,000) will be used for the infiltration of operative field. Surgery will commenced after confirmation of adequate analgesia. Patient’s response to LA infiltration will be evaluated for pain and body movement. Pain will be recorded on a scale of 10 VAS.

Vital parameters will be recorded intra operatively every 5 minutes for first 30 minutes of surgery and 15 minutes intervals till the end of surgery. At every 30 minutes sedation level will be assessed by RSS, if RSS was <3 IV midazolam 0.01 mg/kg will be administered in either group. Similarly, inadequate analgesia will be treated by asking surgeon to infiltrate additional doses of 2% Maintenance infusion will be discontinued 15-20 minutes before the end of surgery at the time of skin closure. All adverse events like bradycardia (HR < 45 beats/min ), hypotension( MAP <50 mm hg sustained for > 10 min),respiratory depression ( respiratory rate < 10 breaths/min ), oxygen desaturation( SPO2 <90 %), nausea or vomiting will be recorded. Bradycardia will be managed by IV inj. Atropine and IV fluids or inj. Mephenteramine used for management of hypotension. Number of times patient had movement during surgical procedure will be recorded.

Patient will be shifted to post anaesthetic care unit and monitored for haemodynamic parameters, analgesia , and adverse events if any within 4 hours after completion of surgery. Every 30 minutes RSS will be assessed and first rescue analgesic will be given at VAS > 4 and will be documented. Patients will be observed for 4 hours post operatively, during which patient’s satisfaction by IOWAscale, pain and sedation related data, Modified Aldrete score and any other remarks will be recorded.All data will be recorded in a structured case record form.