The Study of Regional Hemodynamic Changes After Specific Brachial Plexus Block by Ultrasound Guidance

Phase 1 Sympathetic block leads to vasodilatation and increases in blood flow. However, regional hemodynamic changes of radial and ulnar artery after specific nerve block of brachial plexus remains unclear. The aim of the study is to assess the effect of specific nerve block of brachial plexus on hemodynamics of upper extremity, and provides evidence for further research in patient undergoing microvascular surgery. Phase 2 There is no literature about dose-finding studies of sympathetic block after brachial plexus block. Little is known regarding the relationship between concentration of local anaesthetic and vasodilation of upper extremity. The aim of this randomized, double-blind, prospective dose-response study is to determine the ED50 and ED95 of ropivacaine in sympathetic block of upper extremity after supraclavicular block