A comparison of three drug combinations for sedation during middle ear surgeries under local Anesthesia: A multicentric randomized double blind study

Background: during middle ear surgeries (mes) done under local anesthesia (la),patients may feel discomfort due to noise of suction,manipulation of instruments,positioning of head-neck and sometimes due to pain. a bloodless microscopic field is also essential to facilitate surgical exposure in mes. various combinations of analgesics and sedatives have been tried to alleviate apprehension of the patients and improve microscopic field which may result into reduction in surgical time. in the present study,we have compared dexmedetomedine (dex) with midazolam-fentanyl (mf) and pentazocine- promethazin e (pp) combinations for their sedoanalgesia,anxiolysis and other pharmacological effects when administered during mes,not lasting for more than 60 min. material and methods: ninety american society of american society of anesthesiologists (asa) group i /ii patients admitted in either of the three hospitals during may 2014 to january 2015 for mes under la were randomly divided into three groups by an independent observer. group d received intravenous bolus of injection dexmedetomidine 1 µg/ kg over 10 min. group mf received injection midazolam 0.06 mg/ kg + inj. fentanyl 1 µg/ kg and group pp received injection pentazocine 0.3 mg/kg + injection promethazine 0.5mg/kg given intravenously followed by la before taking incision for the surgery. need of a rescue sedoanalgesic dose of (midazolam 0.01 mg/kg + fentanyl 0.5 µg/kg) during the surgery was noted. all the patients received 500 ml of normal saline infusion till the end of the surgery. all surgeries were finished within 60 min. vital parameters and ramsay sedation score (rss) of the patients were noted from the time of administration of sedative till the end of the surgery. patient and surgeon satisfaction scores were recorded immediately after the surgery. drug combinations of three groups were compared for their effectiveness,adverse effects and satisfaction scores in given doses. children,mentally unstable patients,uncooperative patients,patients requesting general anesthesia,patients with known sensitivity to local anesthetic drug lignocaine,and allergy to study drugs,pregnant and lactating females were excluded from the study. results: rss were satisfactory in group d and group mf but not in group pp. percentage of patients requiring rescue sedoanalgesic dose of (midazolam 0.01 mg/kg + fentanyl 0.5 µg/kg) was the highest (20%) in group pp. it was the least in group d. intraoperative heart rate and mean arterial pressure in group d were significantly lower than the baseline values and the corresponding values in group mf and group pp. incidence of postoperative nausea was higher in group pp. one patient in group d had significant bradycardia with hypotension while one patient in group mf got desaturated needing oxygen therapy. statistically significant number of patients from group d had bloodless microscopic field compared to group mf and group pp. surgeon satisfaction scores which showed statistically significant correlation with type of microscopic field were better in group d. patient satisfaction scores were better in group d than group mf and group pp. conclusion: out of the sedoanalgesics tested,dexmedetomidine was found to be the best drug for mes patients performed under local anaesthesia. it produced near bloodless microscopic surgical field with better surgeon and patient satisfaction. © journal of krishna institute of medical sciences university