Influence of extracorporeal circulation on the kinetics of procalcitonin

Subject of the study

There are a number of clinical and laboratory parameters available for diagnosis of infections. The informative value postoperatively on the start and course of an infection is, however, considerably reduced. Extracorporeal circulation provokes a systemic immunological reaction, which shows changes of all parameters measurable at present. Procalcitonin is a newmarker for bacterial and viral infections. The aim of this study was to evaluate the kinetics of procalcitonin after cardiac surgery using extracorporeal circulation. In a second phase patients were examined who had a demonstrated postoperative infection. Procalcitonin values should be correlated with the occurrence, course and intensity of the infection.

Materials and Methods

39 patients (mean age 66.4 years, 32 men) with uncomplicated course after ACVB operation were enrolled in a phase I study. Samples were collected preoperative, in the 1st, 6th and 12th postoperative hours and then every 24 h up to and including the 5th day. In phase 2, 20 patients (mean age 68.2 years, 10 men) were examined in whom a demonstrable infection was found postoperatively after cardiac surgery.

Results

Procalcitonin rises significantly within the first 24 h after extracorporeal circulation. The serum levels measured, however, are still within the normal range for healthy patients. Standard infection parameters which are used routinely in clinical situations show, in contrast, clearly significantly false positive values from the start of the 6th postoperative hour onwards. The serum values obtained in phase 2 showed that in some patients (8/20) there was a significant procalcitonin rise before the occurrence of a clinically manifest infection. In 3 patients there was no increase in the serum level, even in the course of the infection.

Conclusion

Procalcitonin is a new parameter that is not influenced by extracorporeal circulation which can be used for the diagnosis of an early postoperative infection.

A closed system with reduced blood/air activation was used in all patients. It must be determined in further studies what influence different perfusion techniques have on the kinetics of procalcitonin.