Shivering is a common and significant complication following spinal anesthesia, with a reported incidence of 40-60% especially in trauma patients due to pain, stress response, blood loss, and disrupted thermoregulation. Shivering increases oxygen demand, impairs monitoring, and reduces patient comfort. Effective pharmacologic prevention of shivering is crucial in this population.

Dexmedetomidine is a highly selective α2-adrenoreceptor agonist. It is widely used as an adjunct to general as well as regional anesthesia for better hemodynamic stability, sedation, and prolonged duration of regional anesthesia and is effective in reducing shivering by centrally modulating thermoregulation.

Midazolam, a GABA-A agonist, Intravenous midazolam premedication is commonly used for conscious sedation, anxiolysis, and amnesia with spinal anesthesia is also known to have anti-shivering properties attributed to its action on GABA-A receptors, promoting anxiolysis and possibly resetting the hypothalamic thermoregulatory threshold.

There are limited clinical data comparing the effect of intravenous dexmedetomidine and midazolam and its effect on shivering

Inclusion Criteria:

• : ASA I-II Adult trauma patients (age 18-60 years). Undergoing lower limb orthopedic surgery with tourniquet under spinal anesthesia

Exclusion Criteria:

- Allergy to study drugs. Severe cardiovascular, hepatic, or renal disease Hypovolemic shock. History of psychiatric illness or chronic sedative use. Bradycardia (<50 bpm), heart block, or uncontrolled hypotension. Febrile illness or use of active warming devices