The immature-to-total neutrophil ratio (IT ratio) is a sensitive indicatorof sepsis after paediatric cardiopulmonary bypass

Cardiopulmonary bypass (CPB) causes a systemic inflammatory response syndro me (SIRS) with activation of neutrophils (increased immature-to-total neutr ophil ratio, IT ratio). Does an additional inflammatory response induced by sepsis further increase the IT ratio, so that it can still be used as an i ndicator of sepsis? In 160 children we analysed retrospectively the IT rati os from the dau before CPB to the 10th day after the operation (controls). The 95% confidence limits of the controls were plotted against postoperativ e day and compared with the IT ratio courses in all children of a 4-year pe riod who developed sepsis during the first 10 days after CPB. All septic ch ildren (n = 9) had IT ratios above the upper 95% confidence limits of the c ontrols on the day of positive culture or on the following day. The IT rati o remains a sensitive indicator of sepsis even after CPB.