Nucleated red blood cells and serum lactate values on days 2 and 5 are associated with mortality and morbidity in VLBW infants

To correlate nucleated red blood cell counts and serum lactate concentrations on day 2 and 5 of life with morbidity and mortality in very low birth weight infants and to determine corresponding cutoff values.

Retrospective analysis in a cohort of very low birth weight infants.

250 very low birth weight infants were included in this study. Gestational age ranged from 23 to 35 weeks (mean 29.04) and birth weight was 320–1500 g (mean 1047.9). 55 (22%) patients developed intraventricular hemorrhage, 55 (22%) bronchopulmonary dysplasia, 12 (4.8%) periventricular leukomalacia, 93 (37.2%) retinopathy of prematurity, and 1 (0.4%) necrotizing enterocolitis. Mortality rate was 25/250 (10%). Nucleated red blood cells and serum lactate on day 2 of life were associated with mortality (p < 0.001). Serum lactate on day 5 of life demonstrated an association with retinopathy of prematurity (p = 0.017), bronchopulmonary dysplasia (p = 0.044), and intraventricular hemorrhage (p < 0.001). Cutoff values predicting mortality were >89.5 nucleated red blood cells/100 leucocytes (sensitivity 68.2%, specificity 89.0%) and serum lactate concentrations >8.5 mmol/l (sensitivity 69.6%, specificity 93.5%) on day 2 of life.

We conclude that both nucleated red blood cell count and serum lactate concentration are valuable biomarkers in predicting important outcome parameters in very low birth weight infants.