Early release pattern of S100 protein as a marker of brain damage after warm cardiopulmonary bypass

Warm blood cardioplegia may be more beneficial to the heart than cold cardi oplegia, but the effects of warm cardiopulmonary bypass and warm blood card ioplegia on the brain are controversial. S100 protein is an early marker of brain damage and has been detected alter cold cardiopulmonary bypass. We s tudied S100 concentrations in 20 patients undergoing coronary artery bypass surgery before and after warm cardiopulmonary bypass (34-37 degrees C) usi ng warm blood cardioplegia (37 degrees C) for all patients. The peak level of S100 protein occurred immediately after warm cardiopulmonary bypass, the n decreased progressively until the last measurement at 4.5 h after bypass. The peak level appears to be dependent upon the age of the patient, with t he following regression equation: y = -3.2 + 0.08x, where y is S100 protein concentration ill mu g.l(-1) and x is patient age in years. Further studie s are needed to investigate the clinical significance of this early release pattern. Patient age should be taken into account when studying S100 prote in levels after cardiopulmonary bypass.