368 - The Predictive Utility of Lactic Acid in Hospitalized Infants

Poster Number: 368
Publication Number: 368.132

K. Taylor Wild, CHOP, Philadelphia, PA, United States; IBRAHIM F. GEORGE-SANKOH, CHOP, Aldan, PA, United States; Rebecca Ganetzky, CHOP, Philadelphia, PA, United States

Background: Hyperlactatemia is a relatively common finding in hospitalized infants and can be due to inborn errors of energy metabolism (IEEM), but can also be secondary to cardiac dysfunction, tissue anoxia, and severe catabolic states, such as infection and dehydration.

Objective: To analyze clinical and laboratory characteristics of all hospitalized infants with hyperlactatemia to predict which infants might have IEEM.

Design/Methods: Retrospective cohort study of all hospitalized infants aged 0-90 days from 2012-2020 with a lactate level ≥ 5 mmol/L. For each infant, demographic information, echocardiograms, and genetic and metabolic testing were reviewed. Infants were assigned to a primary diagnostic category of IEEM, congenital heart disease (CHD), sepsis, hypoxic injury, or other.

Results: Charts were analyzed for 976 infants aged 0-90 days of life with a lactate level ≥ 5 mmol/L. Cohort characteristics are shown in Table 1. The median lactate level was 8 mmol/L (interquartile range 6-12 mmol/L). Mortality was 30% (Nf291) overall, but was 51% among infants found to have an IEEM. Genetic testing was diagnostic in 15% (Nf148), including 90% (n=37) of infants with laboratory criteria consistent with an IEEM.

Figure 1 shows a beeswarm plot of lactate levels by primary diagnostic category. While the majority of infants with an elevated lactate had CHD, a higher percentage of these infants had lactate levels < 10 mmol/L compared to infants with IEEM who had significantly higher elevations of lactate. Overall, the median lactate for infants with IEEM was 11.5 mmol/L (interquartile range 8-15.5 mmol/L). Infants with hypoxic ischemic encephalopathy (HIE) also had a profound lactic acidosis with a median lactate of 9 mmol/L (interquartile range 7-12 mmol/L). Significant differences were observed between IEEM vs CHD (p < 0.05, ANOVA), IEEM vs sepsis (p=0.03, ANOVA), and IEEM vs other (p < 0.001, ANOVA), as well as between CHD and other (p < 0.01, ANOVA). While lactate alone could not differentiate between IEEM and other primary diagnoses, lactate was significantly higher in infants with IEEM than in all other groups.Conclusion(s): Metabolic screening labs and comprehensive genetic testing, such as rapid whole exome or genome sequencing, should be considered in infants with persistent hyperlactatemia > 10 mmol/L, particularly without evidence of CHD, HIE, or sepsis. Given relatively high mortality, it is important to identify the etiology of hyperlactatemia as soon as possible.
Table 1: Cohort Characteristics (Nf976)
Figure 1: Lactate Levels by Primary Diagnostic CategoryFigure 1: Beeswarm Plot of lactate levels by primary diagnostic category. Analysis of variance (ANOVA) using a Tukey’s HSD (honestly significant difference) test shows that peak lactate is significantly higher in infants with IEEM vs CHD (p < 0.05), IEEM vs sepsis (p < 0.05), and IEEM vs other (p < 0.001), as well as higher in CHD vs. other (p < 0.01).
* p < 0.05, **p < 0.01, and ***p < 0.001.