This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Intravenous Anesthetic Agents, Subject name: Anaesthesia
Intra-aerial injection of thiopentone. All true except:- 
Select and explain. 
A. Intra-aerial thiopentone can form crystals in aerioles & capillaries and cause intense vasoconstriction, B. It should be treated promptly with papaverine and lidocaine, C. Treatment of choice is stellate ganglion block, D. Heparinization can also be done
C: Treatment of choice is stellate ganglion block
Answer: C: Treatment of choice is stellate ganglion block 
Explanation: If other measures fail then we can go for stellate ganglion block. Intra-aerial injection may cause acute, severe extremity ischaemia and gangrene. The degree of injury is related to the concentration of the drug. Treatment: Theneedle should not be removedand saline is administered the same needle so as to dilute the drug Administering heparinto prevent thrombosis aery dilators can be used Brachial plexus block or stellate ganglion blockto relieve vasospasm