Serum Concentrations of Interleukin-6, Procalcitonin, and C-Reactive Protein: Discrimination of Septical Complications and Systemic Inflammatory Response Syndrome after Pediatric Surgery

Early differentiation between sepsis and systemic inflammatory response syndrome (SIRS) is useful for therapeutic management in neonates and infants after surgery.To compare the early (first 2 days) diagnostic value of interleukin-6 (IL-6), procalcitonin (PCT), and C-reactive protein (CRP) after surgery in the differentiation of subsequent SIRS and septic complications.IL-6, PCT, and CRP were measured 0, 24, and 48 hours after surgery in neonates and infants with clinical suspicion of postoperative sepsis. Sensitivity, specificity, and predictive values for SIRS/septic complications were calculated.A total of 31 out of 205 neonates and infants showed clinical signs for postoperative sepsis and underwent sepsis work-up. Nine patients developed septic complications, sixteen patients met criteria for SIRS, and six patients showed an uneventful postoperative course during the first five postoperative days. IL-6, PCT, and CRP levels increased in all subgroups after surgery and were significantly higher in the sepsis group (p 0.05). IL-6 peaked immediately, CRP at 24 to 48 hours, and PCT at 24 hours after surgery. Sensitivity and specificity (area under the curve) for IL-6 (cutoff 673 ng/dL) were 94.4 and 75% (86.2%), for CRP (cutoff 1.48 mg/dL) 76.2 and 75.0% (88.1%), and for PCT (cutoff 16.1 mg/L) 66.7 and 57.1% (65.6%).IL-6 appears to be an early marker for severe bacterial infections with high sensitivity. IL-6 and CRP were the most reliable markers for the discrimination between SIRS and sepsis within the postoperative period.