Inadvertent intra-arterial injection of thiopentone.

A case is recorded in which intra-arterial injection of thiopentone 2.5 per cent was made into an aberrant branch of the radial artery at the lateral aspect of the wrist. Although the intra-arterial injection of thiopentone is a fairly uncommon accident, especially on the dorsum of the hand, nevertheless, precautions should always be taken to avoid it. These precautions should include palpating for a pulse before application of a tourniquet and after removal of the tourniquet, and checking for backflow of blood after insertion of the cannula. The anaesthetist should always have a high index of suspicion, should use a vessel which is significantly remote from any palpable pulse and should always pause after a test dose of one or two ml of thiopentone solution to ensure that the injection is not uncomfortable. Some of the anatomical abnormalities to be found in the arterial supply to the forearm and hand have been described, and the immediate and late treatment of accidental arterial injection of thiopentone has also been detailed.