Effect of cardiopulmonary bypass on serum procalcitonin and C-reactive protein concentrations

We have measured serum procalcitonin (PCT) concentrations after cardiac sur gery in 36 patients allocated to one of three groups: group 1, coronary art ery bypass grafting (CABG) with cardiopulmonary bypass (CPB) (n = 12); grou p 2, CABG without CPB (n= 12); and group 3, valvular surgery with CPB (n = 12). Serum PCT and C-reactive protein (CRP) concentrations were measured be fore operation, at the end of surgery and daily until postoperative day 8. Serum PCT concentrations increased, irrespective of the type of cardiac sur gery, with maximum concentrations on day 1: mean 1.3 (SD 1.8), 1.1 (1.2) an d 1.4 (1.2) ng ml(-1) in groups 1, 2 and 3, respectively (ns). Serum PCT co ncentrations remained less than 5 ng ml(-1) in all patients. Concentrations returned to normal by day 5 in all groups. To determine the effect of the systemic inflammatory response (SIRS) on serum PCT concentrations. patients were divided post hoc, without considering the type of cardiac surgery, in to patients with SIRS (n = 19) and those without SIRS (n = 17). The increas e in serum PCT was significantly greater in SIRS (peak PCT 1.79 (1.64) ng m l(-1) vs 0.34 (0.32) ng ml(-1) in patients without SIRS) (P = 0.005). Sampl es for PCT and CRP measurements were obtained from 10 other patients with p ostoperative complications (circulatory failure n = 7; active endocarditis n = 2; septic shock n = 1). In these patients, serum PCT concentrations ran ged from 6.2 to 230 ng ml(-1). Serum CRP concentrations increased in all pa tients, with no differences between groups. The postoperative increase in C RP lasted longer than that of PCT. We conclude that SIRS induced by cardiac surgery, with and without CPB, influenced serum PCT concentrations with a moderate and transient postoperative peak on the first day after operation. A postoperative serum PCT concentration of more than 5 ng ml(-1) is highly suggestive of a postoperative complication.