Prognostic value of nucleated red blood cells in critically ill children

Is there an association between the presence of nucleated red blood cells (NRBCs) in the peripheral blood and outcomes in critically ill children?

Prospective observational study conducted in 2008 (January to December) in a multidisciplinary paediatric intensive care unit (PICU) of a tertiary children's hospital. We provide univariate analysis, stratified by age group (neonates and children >28 days of age), and multiple logistic regression, comparing clinically important outcomes (death, ventilation, renal replacement therapy, inotropic support) with haematological (NRBC, haemoglobin, platelets, leucocytes), illness severity (expected mortality [paediatric index of mortality, PIM2]), demographic (age, sex) and diagnostic parameters and length of stay. Haematological parameters correspond to the first 24 hours of PICU admission.

Out of 670 patients, 195 (29.1%) were NRBC positive and 475 (70.9%) were NRBC negative. In the neonatal age group (n = 232), patients who died, were ventilated or received inotropic support had significantly more NRBCs than patients without these conditions (p = 0.032, 0.038 and 0.029, respectively). In the child age group (n = 438), only renal replacement therapy was significantly associated with NRBC (p <0.001). High PIM score (p <0.001) and longer length of stay (p <0.001) were independently associated with bad outcomes (composite endpoint: mortality and/or ventilation and/or renal replacement therapy and/or inotropic support); NRBC positivity was not an independent predictor of bad outcome (odds ratio 1.44, 95% confidence interval 0.62‒3.41).

NRBCs are not an independent risk factor for bad outcomes in paediatric intensive care. However, NRBCs may have some prognostic value in the first month of life. In children >1 month of age, the association between NRBC and outcome is much less pronounced.