The aim of this study is to compare the efficacy of intrathecal dexmedetomidine versus intrathecal fentanyl when added to hyperbaric bupivacaine in the prevention of post-spinal shivering in patients undergoing hip arthroplasty surgeries and to observe their effects as regards to sedation and intensity of the block.

Preoperative settings:

All patients fulfilling the inclusion criteria who are undergoing hip arthroplasty surgeries and receiving spinal anaesthesia will be randomised into 2 equal groups, namely group D (Dexmedetomidine group) and group F (Fentanyl group).

Routine pre-operative assessment will be done for all patients including routine history taking, clinical examination, and laboratory investigations (complete blood picture, kidney function tests, liver function tests, prothrombin time, partial thromboplastin time).

An informed written consent will be taken from every patient just before the surgery.

Intraoperative and postoperative settings:

On arrival to the operating room, baseline parameters such as ECG, mean arterial blood pressure, heart rate, and oxygen saturation will be recorded. All the patients will be preloaded with 10 ml/kg of Ringer's solution through peripheral intravenous cannula and monitored with five leads electrocardiography, pulse oximetry, and non-invasive blood pressure (NIBP) (which records systolic, diastolic, and mean blood pressure every 5 min intraoperatively and every 15 min in the recovery room, heart rate was recorded in the same intervals).

Under complete aseptic technique, local anaesthetic in the form of 3 ml of lidocaine 2% will be given at the site of spinal injection. Subarachnoid block will be administered in the sitting position midline approach with 25 gauge (Quincke needle) at L3-L4/L4-L5 space.

For group D, the preservative-free dexmedetomidine 100 μg/ml will be loaded into a 100-unit insulin syringe (1 μg/unit) and 5 units will be added to 4 ml (20 mg) of 0.5% hyperbaric bupivacaine.

For group F, fentanyl 25 mcg will be given intrathecally added to 4 ml (20 mg) of 0.5% hyperbaric bupivacaine.

Patients will be immediately placed in the supine position after completing the spinal block.

Inclusion Criteria:

• ASA I, ASA II or ASA III patients scheduled for hip arthroplasty surgeries under spinal anaesthesia.

Age > 20 years.

Exclusion Criteria:

• Patient refusal

  • Patients with known neurologic and psychiatric illness.
  • Contraindications for spinal anaesthesia as bleeding or coagulation test abnormalities, local skin infection at spinal lumbar region, raised intracranial pressure and hypovolemia.
  • Height <150 cm.
  • Systemic disorders like hematological, respiratory, cardiac, renal or hepatic insufficiency.
  • Allergy to any of the drugs used in the study.

All data will be shared once the study is completed