A comparative study of intrathecal 0.5% hyperbaric bupivacaine with dexmedetomidine and 0.5% hyperbaric bupivacaine with fentanyl for lower abdominal surgeries

Background
Adjuvants are added to improve the quality, to accelerate the onset of action and to overcome the problems of spinal anaesthesia. Depending on the purpose various adjuvants like morphine, fentanyl, clonidine, midazolam and dexmedetomidine are added. Adjuvants are administered by various routes like epidural, intrathecal and intravenous.

Materials and methods
Following detailed pre-anesthetic check-up, patients were randomised into 2 groups in a sealed envelope, Group D received 2.5ml of 0.5% hyperbaric bupivacaine with 5µg dexmedetomidine and Group F received 2.5ml of 0.5% hyperbaric bupivacaine with 25µg fentanyl.  Subarachnoid block was given between L₃-L₄ space with 25G Quincke spinal needle under aseptic precautions after free and clear flow of CSF in sitting posture. Onset of action, level of blockade, sedation score, duration of analgesia, adverse effects and hemodynamics were monitored. The first rescue analgesia was given when Visual Analogue Scale (VAS) was >4.

Results
In our study dexmedetomidine provided better sensory block, motor block and longer duration of analgesia. The highest sensory level achievedby group D 6(4 – 8) and in group F was 8(6-10)(p <0.005), time of two segment regression in group D110.33 ± 11.544min and group F 81.50±15.6 min (p <0.001), time of regression to S₁ segment group D453.67±23.265 and group F 180.70± 18.235 (p<0.001), motor blockade was in group D 407.53± 18.913 and in group F 149.37± 12.497 (p<0.001) and time to rescue analgesia group D 231.93± 17.836 and group F 160.13± 15.518min (p<0.001). The haemodynamic stability, sedation and side effects were similar in both the groups (p>0.05).

Conclusion
We conclude that dexmedetomidine may be used as an alternate to fentanyl for intrathecal use and it may find a place forregular use in clinical practice.