Arousal from Sedation in Lower Abdominal Surgeries Under Spinal Anesthesia: Comparison Between Dexmedetomidine and Clonidine

Background And Aim: Dexmedetomidine and clonidine are commonly used drugs for sedation during regional anesthesia. However, data regarding arousal time from sedation with these drugs is sparse. Hence, we designed a study to compare arousal time from sedation with dexmedetomidine and clonidine during spinal anesthesia. We also tried to find out the correlation between clinical and objective method used for assessing the depth of sedation.

Materials And Methods: In this study, 120 patients were randomly assigned in two groups to receive either dexmedetomidine (Group DE, n = 60) or Clonidine (Group CL, n = 60). Group DE received 1 μg/kg of dexmedetomidine followed by infusion at 0.5 μg/kg/h while Group CL received 1 μg/kg of clonidine followed by infusion at 1 μg/kg/h and titration until targeted Ramsay sedation scale (RSS) score of 3-5 was achieved and maintained. RSS and bispectral (BIS) were monitored until arousal of the patients. The time to achieve RSS of 2 and BIS of 90 during recovery, the correlation between BIS and RSS score in both the study groups and duration of postoperative analgesia were noted.

Statistical Analysis Used: Chi-square tests for nonparametric data and Student's t-test for parametric data were used. Correlation between RSS and BIS was calculated with spearman correlation method.

Results: Arousal time from sedation and time to reach BIS score 90 was lower for Group DE as compared to Group CL (P = 0.001). Dexmedetomidine also increased the time to first postoperative analgesic request when compared with clonidine (198.23 ± 33.15 min vs. 150.65 ± 28.55 min, P = 0.01).

Conclusions: Intravenous dexmedetomidine infusion has shorter arousal time from sedation than clonidine during spinal anesthesia. A strong correlation exists between BIS and RSS during recovery from sedation.