Early hyperlactataemia in critically ill children

Objective:To examine the relationships between early hyper-lactataemia, aci dosis, organ failure, and mortality in children admitted to intensive care. Design: Prospective observational study. Children with lactate levels > 2 m mol/l were eligible for enrolment. Post-operative patients and those with i nherited metabolic disease were excluded. Seven hundred and five children a dmitted to intensive care were screened, and 50 children with hyperlactatae mia (incidence 7%), aged 20.3 months (0.1-191) were enrolled and followed u p. The Paediatric Risk of Mortality (PRISM) score, Multiorgan System Failur e (MOSF) score, length of ICU stay, and outcome were re corded. Data were c ollected for lactate (mmol/l), pH, and base excess (BE) until 24 h after ad mission. Data are reported as median (range) and were analysed by the Mann- Whitney, Fisher's Exact, and Kruskal-Wallis tests, and chi-squared test for trend. Results: Overall mortality in the screening group was 70/705 (10%). In the study group (n = 50) median PRISM score was 19 (4-49), median MOSF score 2 (1-4), and observed mortality 32/50 (64 %). Median duration of ICU stay was 6 days (2-32) in survivors, and median time until death 3 days (0-13) in n onsurvivors. Eleven nonsurvivors (34 %) died within 24 h. In the screening group, hyperlactataemia on admission identified mortality with likelihood r atio = 15. In the study group, neither the admission lactate (3.8 vs 4.6 mm ol/l, P = 0.27), pH (7.32 vs 7.30, P = 0.6), nor BE (-7.5 vs -8, P = 0.45) differed significantly between survivors and nonsurvivors. Neither the admi ssion nor peak lactate increased with increasing MOSF score (P = 0.5 and 0. 54). The median peak lactate level was 5 mmol/l (2-9.3) in survivors compar ed to 6.8 mmol/l (2.3-22) in nonsurvivors (P = 0.02), and the cumulative av erage lactate level was 2.4 mmol/l (1-4.9) in survivors, compared to 4.5 mm ol/l (1.6-21) in nonsurvivors (P = 0.0003). Persistent hyperlactataemia 24 h after admission identified mortality with likelihood ratio = 7. Conclusion: Hyperlactataemia on admission to intensive care is associated w ith a high mortality in children. Nonsurvivors within this group may be dis tinguished by the peak lactate level, or by persistent hyperlactataemia aft er 24 h of treatment.