Intra arterial injection of thiopentone causes –
Inadverent intra-arterial injection causes local vasoconstriction (vasospasm) and thrombosis which can cause ischemia and gangrene of the limb.
Note-IV injection cause generalized venodilatation due to which there is pooling of blood & hypotension. On the other hand intra-arterial injection results in localized vasospasm of the involved artery.
Vasospasm
Vasodialation
Necrosis of vessel wall
Hypotension