A case is presented in which a relatively modest blood transfusion resulted
in acute hyperkalaemia with a 'near-miss' cardiac arrest. While transfusio
n-related hyperkalaemia usually occurs in association with massive transfus
ions, several factors may have increased the risk of such an acute reaction
. A high index of suspicion is required, especially in patients with risk f
actors. Anaesthetists should not be lulled into a false sense of security s
imply because modest volumes of blood are being transfused.