Diagnosis of infection in paediatric veno-arterial cardiac extracorporeal membrane oxygenation: role of procalcitonin and C-reactive protein

Plasma concentration of procalcitonin (PCT) and its value in the diagnosis of infection in paediatric patients treated with extracorporeal membrane oxygenation (ECMO) are undefined. This study aimed to define the levels of PCT and C-reactive protein (CRP) in paediatric cardiac ECMO patients and to determine their role in predicting infection, severity of organ dysfunction and clinical outcome. PCT and CRP plasma concentrations were measured daily in 20 consecutive infants and young children treated with veno-arterial ECMO. Each patient was examined daily for signs of infection and multiple organ dysfunction syndrome (MODS). A total of 139 patient days were classified for infection and MODS. The median PCT and CRP plasma concentrations were not increased during infection: 2.4 vs 8.8 ng/ml and 223.8 vs 240.6 mg/l, in patients with vs without infection, respectively. PCT, but not CRP, was significantly elevated during MODS (10.9 vs 1.85 ng/ml) (P = 0.001). The area under the receiver operating characteristic (ROC) curve was 0.984 for PCT (95% confidence interval [CI], 0.962-1.000) compared with 0.347 for CRP (95% CI, 0.211-0.484) (P = 0.001). Only PCT differed significantly in patients weaned from ECMO who survived (2.6 ng/ml) vs patients not weaned from ECMO (10.5 ng/ml) (P = 0.001). The area under the ROC curve was 0.871 (95% CI, 0.786-0.956) compared with 0.261 for CRP (95% CI, 0.145-0.377) (P = 0.001). Neither PCT nor CRP are reliable markers of infection in paediatric cardiac ECMO patients. However, high levels of PCT are associated with MODS. PCT may be used as a prognostic indicator of clinical outcome in this high-risk population.