Abstract
Cardioplegia is used to induce cardiac arrest in order to facilitate cardiac surgery in patients supported by cardiopulmonary bypass. It is administered directly into the coronary vessels after the heart has been isolated from the systemic circulation. We describe the case of a 9-year-old boy who mistakenly received 1 l of high strength St Thomas' Harefield cardioplegia solution delivered into the systemic circulation during cardiac surgery. Although the patient's heart did not stop, the subsequent physiological derangements were severe. The presenting features were refractory hypotension and dilutional anaemia along with severe hyperkalaemia, hypermagnesaemia and hyperchloraemic metabolic acidosis. Local anaesthetic systemic toxicity from the procaine contained within the cardioplegia solution was also a concern. Treatment required vasopressor administration and an extended period of cardiopulmonary bypass while serum electrolyte concentrations were corrected by haemodiafiltration. The systemic administration of cardioplegia solution is a rare but important iatrogenic clinical emergency that anaesthetists working in cardiac centres should be aware of. This case demonstrates that full recovery is possible.