Can acute-phase response biomarkers differentiate infection from inflammation postpediatric cardiac surgery?

Infection is a common serious complication postpediatric cardiac surgery. Diagnosis of infection after cardiopulmonary bypass (CPB) is difficult in the presence of surgical stress, hemodynamic instability, and inflammatory reaction.

The purpose of this study is to investigate the value of available inflammatory biomarkers and its validity to differentiate infection from inflammation postpediatric cardiac surgery and to find the trend and the change in the level of these biomarkers shortly after cardiac surgery.

We conducted a prospective study that included all children who underwent cardiac surgery in Prince Sultan Cardiac Centre-Qassim from November 2013 to October 2015. C-reactive protein, erythrocyte sedimentation rate, white blood cell count, and neutrophil count were measured for all patients presurgery, 4 consecutive days postsurgery, and predischarge. Patients were divided into two groups (the infected and the noninfected group). We compared the level of biomarkers between both groups. Then, we further analyzed the effects of CPB and preoperative steroid on postoperative inflammatory biomarker levels. Collected data were then reviewed and analyzed.

There were 134 pediatric cardiac patients included during the study period. Group 1 (bacterial negative culture group) had 125 cases and Group 2 (bacterial positive culture group) had nine cases. We found no statistically significant difference in inflammatory biomarker elevation between both groups. Only Group 2 had higher (RACHS) Risk adjustment for congenital heart surgery score, more ventilator days, and more drop in platelet count on the 2^nd and 3^rd postoperative days in comparison with the noninfected group 1. Both groups of patients who were in on and off CPB had the same level of inflammatory biomarkers with no significant differences. Giving corticosteroid preoperatively did not affect the trend of biomarker elevation and made no difference when it was compared to the group of patients who did not receive corticosteroid before surgery.

Common inflammatory biomarkers cannot differentiate between infection and inflammation within the first 5 days postpediatric cardiac surgery as these reflect the inflammatory process rather than infection. Trend is more important than single reading.