Tourniquet failure and arterial calcification. Case report and theoretical dangers.

A patient with Mönckeberg's calcinosis is presented in whom a pneumatic limb tourniquet failed to be effective because of calcification of the femoral artery wall. Bleeding from the operation site was noticed to be appreciably greater while the tourniquet was inflated since the cuff, though not occluding the femoral artery, acted as a very effective venous tourniquet. Theoretical risks which might be associated with the use of tourniquets in the presence of arterial calcification are fracture of the calcified vessel wall and systemic overdose of local anaesthetic agent following attempted regional intravenous block. The problem of tourniquet failure in general, and the dangers which might be associated with the use of tourniquets in patients with incompressible arteries, are briefly discussed.