Ionized calcium levels during liver transplantation.

Plasma ionized calcium and total calcium concentrations were measured during 26 liver transplant operations. The level of ionized calcium decreased during the early part of the operation, reaching its lowest point during the anhepatic period, but rose again after revascularization of the new liver. Calcium chloride was given with the aim of reversing these decreases, which were associated with the use of blood products preserved in citrate-phosphate-dextrose anti-coagulant-containing adenine (CPD-A). Ionic hypocalcaemia is a result of intra-operative citrate loading in the presence of poor or absent (during the anhepatic phase) liver function; aggressive correction of low ionized calcium levels, especially during the early stages of the operation, is required to prevent this effect.