A comparative study of two different doses of dexmedetomedine as an adjuvant to lignocaine in infiltration block for tympanoplasty: a triple-blinded, prospective, randomized controlled trial.

Background: The ideal anesthetic drug choice for local infiltration anesthesia under monitored anesthesia care must provide analgesia and patients' comfort along with a bloodless surgical field for patients. We hypothesized that dexemedetomidine can provide better visibility of the surgical field at a higher dose of 1 µg/kg than 0.5 µg/kg, along with providing sedation and analgesia.

Methods: After institutional ethics committee clearance and written informed consent, this prospective, randomized, triple blind study was conducted on ninety patients, between 18- 65 years who were scheduled for tympanoplasty. The patients were randomly assigned to either the dexmedetomidine (DEX) 0.5 group or the DEX 1.0 group, and received 10 ml solution containing 2% lignocaine with 0.5 µg/kg dexmedetomidine, or the 1 µg/kg dexmedetomidine. The operative surgeon performed local infiltration using standardized 5-point infiltration technique around the auricle. The primary objective was to compare the intraoperative bleeding at the surgical site. The comparison of normally distributed variables was conducted using the Student's t-test, whereas non-normally distributed variables was compared using the Mann-Whitney U test. The analysis of qualitative data was conducted using the chisquare/Fisher's exact test. A P value less than 0.05 was considered statistically significant.

Results: The overall bleeding score was significantly higher in the DEX 0.5 group (3.21 ± 0.727) than the DEX 1.0 group (1.43 ± 0.661) (P value < 0.001). The time to first analgesic requirement and surgeon satisfaction score were also significantly higher in the DEX 1.0 group.

Conclusions: Combining dexmedetomidine at a dose of 1 µg/kg with 2% lignocaine for infiltration provided improved analgesia and improved the surgical field during tympanoplasty performed under monitored anesthesia care.