Calcium supplementation during cardiopulmonary bypass in paediatric surgery

This paper reports on the monitoring of plasma ionized calcium (Ca++) levels in children undergoing cardiopulmonary bypass (CPB) for open-heart surgery. The pump was primed with blood treated with either heparin or citrate-phosphate-dextrose (CPD). In certain cases calcium supplementation was used. In all cases a sudden drop in Ca++ levels took place at the start of CPB, followed by a slow recovery. In the patients who received heparinized blood the drop was slight (14%) and recovery fast (10 minutes), but in those who received CPD the drop was excessive (58%) and recovery was still incomplete after 1 hour despite supplementation with 0,5 g calcium gluconate per unit of whole blood. Different supplementation regimens were tried and the optimum was achieved by using 1 g calcium gluconate per unit of whole blood. This limited the drop in the Ca++ level to 42%, and recovery to prebypass levels took place within 45 minutes.