Blood flow in the arm under brachial plexus anaesthesia.

Changes in blood blow and skin temperature have been measured in the arms of twenty patients under brachial plexus anaesthesia. A rise in each was noted in every patient. The patients were subdivided into two groups of ten. The anaesthetic administered to the patients of one group contained adrenaline (1 in 100,000), and the patients in the other group received the same anaesthetic but with no added adrenaline. The rise in flow volume, flow velocity and temperature was greater in the group which received adrenaline. The difference in change of flow volume was significant (P less than 0.05), the difference in temperature rise highly significant (P less than 0.01), but the difference in change of flow velocity was not significant.