Peripheral Nucleated Red Blood Cells and Mortality in Critically Ill Children

The present retrospective cohort study examines whether there is an association between circulating nucleated red blood cells (nRBCs) and mortality in critically ill children. nRBCs are erythropoietic progenitor cells not found in peripheral blood of healthy adults and children beyond the neonatal period. The presence of circulating nRBCs is associated with poor prognosis in adults and neonates, though little is known about their significance in children. Admissions to both the general and cardiac pediatric intensive care unit at the Stollery Children's Hospital in Edmonton, Alberta between January 1, 2015 and December 31, 2017 were examined, and logistic regression was performed to ascertain the association between the peak absolute nRBC counts and in-hospital mortality in critically ill children. A total of 2065 admissions were included. The number of admissions with detectable nRBCs was 386 (prevalence: 13.9%), and the number of deaths was 93 (mortality: 4.5%). A statistically significant association was found between the absolute value of nRBC peak and intensive care unit mortality (odds ratio=1.37; 95% confidence interval: 1.13-1.67; P=0.002) as well as hospital mortality (odds ratio=1.38; 95% confidence interval: 1.12-1.70; P=0.003) independent of the Pediatric Index of Mortality 3 score (PIM3). This result warrants more attention to nRBC values and their potential clinical use.