Abstract: 【Abstract】Objective: To observe clinical effects of dexmedetomidine combined spinal block in lower extremity surgery. Methods: 90 cases of lower extremity surgery patients between 2013 December and 2014 December were selected in our hospital, randomly divided into control group and study group, according to random number table. Intravenous dexmedetomidine is applicated flowing spinal anesthesia within study group (DS group); and spinal anesthesia only within control group patients (S group). Results: there are no significant hemodynamics difference between D + S group and S group patients. But post-anesthesia shivering, intra-operative tourniquet reaction, and post-operative nausea and vomiting significantly reduced (P <0.05). Conclusion: dexmedetomidine combined spinal anesthesia can significantly improve the quality of anesthesia, and decrease post-anesthesia shivering, intra-operative tourniquet reaction, and post-operative nausea and vomiting.

Key words: Dexmedetomidine, spinal anesthesia, lower limb surgery