This study evaluated the effect of dexmedetomidine iv in three different doses in the treatment of shivering in patients undergoing minor elective abdominal surgery under spinal anesthesia, in comparison with intravenous pethidine.

Among the pharmacological agents used in treatment of shivering, pethidine (meperidine) has been shown to be one of the most effective treatments.The α-2 receptor agonists are another important class of anti-shivering drugs that, unlike meperidine, produce little respiratory depression.

Dexmedetomidine is a highly selective α-2 adrenoceptor agonist with potent effects on the central nervous system . Intravenous dexmedetomidine reduces both the vasoconstriction and shivering thresholds . Clinical studies had demonstrated the efficacy of dexmedetomidine in prevention of shivering . Few clinical trials investigated its efficacy in treatment of established shivering. The optimum dose for shivering control with the least hemodynamic derangements is still under research.

Inclusion Criteria:

• American Society of Anesthesiologist class I or II scheduled for elective minor lower abdominal operations under spinal anesthesia for an anticipated duration of >60 and <180 min. (e.g. inguinal herniorRaphy, umbilical hernia repair) who developed shivering during the intra or postoperative period

Exclusion Criteria:

• Patients with BMI>30 kg /m2
• Initial body temperature >38 C or <36 C and those with a history of convulsions
• Multiple allergies
• Thyroid disease
• Parkinson's disease
• Dysautonomia
• Raynaud's syndrome
• Hypertension
• Coronary artery disease or other cardio-respiratory or neuromuscular pathology
• Middle ear pathology
• A known history of alcohol use
• Treatment with sedative hypnotic agents or vasodilators
• Having contraindications to spinal anesthesia