The Prognostic Value of Initial Blood Lactate Concentration Measurements in Very Low Birthweight Infants and Their Use in Development of a New Disease Severity Scoring System

Objectives: To investigate the predictive value of the Clinical Risk Index for Babies (CRIB) score in current practise, the predictive value of blood lactate concentrations ([L]) and to develop a new clinical scoring system for very low birthweight (VLBW) babies.

Methods: The predictive ability of CRIB, [L] and the development of the new score was based on retrospective data collected from all inborn VLBW babies born between March 2001 and February 2004 in a tertiary neonatal unit. Predictive ability was determined from area under the receiver operator curve (AUC). A new score was developed and validated with a second cohort of VLBW babies.

Results: 408 babies were studied in the development cohort and 275 in the validation cohort. AUC for CRIB was 0.933 (95% CI 0.897-0.969). Initial [L] was significantly higher in babies who died than in those who survived (median (range) 9.2 (1.26-21.1) vs 3.64 (0.67- 17.9) mmol/l, p<0.0001) as was the highest [L] in the first 12 h (10.2 (3.37-26) vs 3.84 (1.05-20.7) mmol/l, p<0.0001). A new score was developed using; highest [L], gestation and the presence of life-threatening malformation. AUC for the new score was 0.918 (95% CI 0.876-0.961) in the development cohort and 0.859 (95% CI 0.805-0.913) in the validation cohort.

Conclusions: CRIB score retains its predictive ability for mortality in VLBW babies. Early hyperlactataemia is a predictor of death in VLBW babies. The new score appears to perform as well as CRIB but requires fewer data items.