Comparison of Intrathecal Dexmedetomidine and Fentanyl on Vital parameters, stress response and Post-operative pain in Laparoscopic cholecystecomy surgeries.

Intervention1: Fentanyl: Intrathecal Fentanyl 50mcg to be used.
Intervention2: Dexmedetomidine: Intrathecal Dexmedetomidine 10mcg to be used.
Intervention3: Dexmedetomidine: Patients in this group will be categorised as Group1, and 10mcg of the drug will be given Intrathecal route. Its effect will be studied on hemodynamic stress response during pneumo-peritoneum stage of surgery and post-operative analgesia up to 24 hours.
Intervention4: Fentanyl: Patients included in this group will be categorised as Group2, and will be given 50mcg of the drug intrathecal route.Its effect will be studied on hemodynamic stress response during pneumo-peritoneum stage of surgery and post-operative analgesia up to 24 hours.
Control Intervention1: Normal Saline: Patients in this group will be categorised as Group3 and will be injected equal volume (1ml) of normal saline intrathecally.Its effect will be studied on hemodynamic stress response during pneumo-peritoneum stage of surgery and post-operative analgesia up to 24 hours.
Primary outcome(s): Hemodynamic stress response to pneumo-peritoneumTimepoint: At the end of surgery.
Study Design: Randomized, Parallel Group, Placebo Controlled Trial
Method of generating randomization sequence:Computer generated randomization Method of allocation concealment:On-site computer system Blinding and masking:Participant, Investigator and Outcome Assessor Blinded