A prospective, randomized, comparative controlled clinical trial, aiming to compare the use of intrathecal dexmedetomidine by intravenous dexmedetomidine in concern of the first request to analgesia. The secondary end-points were the total postoperative analgesic consumption as well as the VAS.

Seventy patients undergoing lower limb surgeries were included in this study. Using a random number sequence, patients were enrolled in one of two groups: Group T receiving 5 µg of dexmedetomidine (Precedex® 100 µg/mL, Hospira, Inc., IL, U.S.A.) combined with 12.5 mg of 0.5% hyperbaric bupivacaine (Marcaine® Spinal Heavy; Astra, Sodertalje, Sweden) and Group V receiving the same bupivacaine DOSE AND 0.75 microgram/kilogram of body weight dexmedetomidine intravenously. Dexmedetomidine 100 µg/mL was mixed with preservative-free normal saline to 10 µg/mL. The 0.5 mL of dilute dexmedetomidine was added to the bupivacaine in group T. An independent investigator prepared the drug solutions and provided the coded drug to the anaesthetic administrator before the start of the anaesthesia. The anaesthetic administrator, patients, outcome assessors, and data analysts were blinded to the allocation. Spinal Anesthesia Patients were hydrated with 500 mL of 0.9% sodium chloride solution before anaesthesia. The spinal puncture was performed at L3-4 or L4-5 with a midline approach using a 25 G Quincke needle in the lateral decubitus position. After confirmation of free flow and clear cerebrospinal fluid, the drug was administered and the patients were then placed in the supine neutral position.

Assessment: The primary end-point of this study was the first request to analgesia. The secondary end-points were the total postoperative analgesic consumption as well as the VAS.

Inclusion Criteria:

• ASA I-II patients
• age 18-65 years
• scheduled for lower limb surgery
• spinal anaesthesia

Exclusion Criteria:

• patients with coagulopathy
• infection at the site of lumbar puncture
• beta-blockers or calcium channel blockers usage
• hypersensitivity to Bupivacaine or Dexmedetomidine
• any other contra-indications for spinal anaesthesia.

double blinded