A comparison between intrathecal dexmedetomidine with hyperbaric bupivacaine and intrathecal fentanyl with hyperbaric bupivacaine in lower abdominal surgeries: A prospective double-blinded study

Abstract

Background: The aim of this study is to compare the efficacy and safety of injection dexmedetomidine 5 μg and injection fentanyl when given intrathecally as adjuvant to injection bupivacaine in patients undergoing total abdominal hysterectomy in terms of the following parameters: (1) Characteristics of onset of sensory and motor block. (2) Characteristics of regression of sensory and motor block. (3) Level of sedation (4) Hemodynamic stability as assessed by pulse rate, systolic, and diastolic blood pressure (BP) and requirements of vasopressors. (5) Quality of postoperative analgesia as assessed by visual analog scale. (6) Evaluation of complications associated with injection dexmedetomidine and injection fentanyl when used as an adjuvant to injection bupivacaine. Materials and Methods: Ninety patients of the American Society of Anesthesiologists Class I and II posted for lower abdominal surgeries were allocated randomly into three groups of thirty patients each. C group: (n = 30) received 0.5 mL normal saline with hyperbaric bupivacaine 17.5 mg in 3.5 mL to make 4 mL. D group: (n = 30) received dexmedetomidine 5 μg with hyperbaric bupivacaine 17.5 mg in 3.5 mL diluted with 0.4 mL normal saline to make it 4 mL. F group: (n = 30) received fentanyl 25 μg with hyperbaric bupivacaine 17.5 mg in 3.5 mL to make 4 mL. Results and Conclusion: We observed that the groups were comparable with respect to demographic data (age, weight, height and duration of surgery) and onset time of sensory and motor blockade. The onset of sensory and motor block was slightly delayed in both groups. Two segment regression time of sensory blockade and time to reach Bromage scale 0 was greatly significant in dexmedetomidine and fentanyl. However, in comparison of the two, dexmedetomidine was clearly superior. The groups were comparable in terms of hemodynamic parameters, oxygen saturation, and respiratory rate, though there had been a statistically significant fall in BP and heart rate when compared to baseline. Sedation scores were found to be statistically significantly higher in group dexmedetomidine as compared to Fentanyl. The results showed statistically significant increase in the duration of postoperative analgesia in group using dexmedetomidine as compared to group fentanyl. The requirement of first rescue analgesic was greatly significant. The group using fentanyl had an postoperative pain free period of unto 4 h and dexmedetomidine had analgesia period unto 7 h. We found some adverse effects such as hypotension, bradycardia, nausea and vomiting with dexmedetomidine and fentanyl; however, the results were statistically insignificant. To conclude, the addition of dexmedetomidine prolonged the sensory and motor block significantly when used with hyperbaric bupivacaine intrathecally, to a much greater extent to the addition of fentanyl without increasing the incidence of significant adverse effects.