During preoperative visit patient’s detailed history, general physical examination and systemic examination will be carried out. History of any significant medical illness will be elicited. Airway, respiratory system and cardiovascular system will be assessed.

Only ASA grade І and ІІ patients within the age group of 18 to 60 years of either sex undergoing elective lower limb surgeries will be included in our study. A written informed consent will be taken.

Patient will be shifted to operation table, IV access will be obtained on forearm with 18 Gauge IV cannula and Ringer’s lactate solution 500ml will be infused intravenously before the block. The monitors will be connected to patient which include non-invasive blood pressure. Oxygen saturation using pulse oximeter.  Baseline PR, BP and SpO2 will be recorded.

      Under strict aseptic precautions, lumbar puncture will be performed in left lateral position by midline approach by using 26G Quincke spinal needle at L3-L4 intervertebral space and study drug will be injected intrathecally after confirming clear free flow of CSF. Patient’s vitals will be monitored continuously using mutli-parameter monitor. After spinal anaesthesia, Oxygen (5L/min) by facemask will be given, Fluid therapy will be maintained with Lactated Ringer’s solution (10ml/kg/hr).