Repeated blood lactate measurements during clinical care of children with cerebral malaria

Abstract

Background Admission blood lactate has previously guided therapy and is a valid estimator of prognosis in children with cerebral malaria (CM). Since bolus intravenous fluid administration to children with febrile coma and signs of hypovolemia (including high blood lactate) may be harmful, the use of blood lactate to guide therapy has waned. Its utility as a prognostic biomarker, either at admission or during hospitalization, remains unclear. Methods We performed a retrospective cohort study of 1674 Malawian children with CM hospitalized from 2000–2018 who had blood lactate measurements every 6 hours for the first 24 hours. We evaluated the strength of association between admission lactate or values measured at any time point in the first 24 hours post-admission, and outcomes (death or neurologic disability in survivors). We assessed the optimal duration of lactate monitoring of children with CM. Results When lactate is analyzed as a continuous variable, children with CM who have higher values at admission have a 1.05-fold higher odds (95% CI: 0.99–1.11) of death compared to those with lower lactate values. Children with higher blood lactate at 6 hours have 1.16-fold higher odds (95% CI: 1.09–1.23) of death, compared to those with lower values. If lactate levels are dichotomized into hyperlactatemic (lactate > 5.0 mmol/L) or not, the strength of association between admission lactate and death increases (OR = 2.49, 95% CI: 1.47–4.22). Neither blood lactate levels obtained after 18 hours post-admission nor trends in lactate concentrations during the first 24 hours of admission are associated with outcomes. Blood lactate during hospitalization is not associated with adverse neurologic outcomes in CM survivors. Conclusions In children with CM, blood lactate is associated with death but not neurologic morbidity in survivors. To comprehensively estimate prognosis, blood lactate in children with CM should be assessed at admission and for 18 hours afterwards.