The best questions often stem from the inquisitive learner. As educators, we love, and are always humbled by, those moments when we get to say, “I don’t know.” For some of these questions, you may already know the answers. For others, you may never have thought to ask the question. For all, questions, comments, concerns, and critiques are encouraged. Welcome to the Kids Korner.
Question 1: Are serum lactate levels good screening tools for sepsis in pediatric patients?
In adults, a screening serum lactate ≥4 mmol/L identifies patients at significantly higher risk of death from sepsis, serving as a valuable risk stratification tool.1 For this reason, it is common practice to obtain this test in adult patients suspected of having sepsis. However, in children, there are considerably less data on this topic.
The literature on this topic has typically been limited to pediatric ICU patients. One early study was a very small (n=11) prospective pediatric ICU study.2 The authors evaluated children ages 1 to 18 years in septic shock who required mechanical ventilation. In these 11 children, they drew 53 serum lactate samples—an initial sample in each, plus six-hour trending follow-up samples. In these patients, only 15 of 53 (29 percent) samples were >1.8 mmol/L. Of the initial lactates drawn, only 2 of 11 (18 percent) were >4 mmol/L, suggesting that serum lactates are not good screening tests for severe sepsis/septic shock in pediatric patients. Another retrospective study of 289 children younger than 18 years evaluated screening serum lactate measurements as an outcome predictor in a pediatric emergency department.3 Death was not predicted by the serum lactate in that study.
A later prospective observational cohort study (n=239) evaluated screening serum lactate levels in children younger than 19 years if they met systemic inflammatory response syndrome (SIRS) criteria.4 Predefined levels of serum lactates were normal (< 2 mmol/L), intermediate (2–4 mmol/L), and hyperlactatemia (>4 mmol/L). The primary endpoint was end-organ dysfunction within 24 hours. For patients with hyperlactatemia (>4 mmol/L), the sensitivity for end-organ dysfunction was only 31 percent (4 of 13); the majority of patients with end-organ damage within 24 hours of ED presentation presented in the <4 mmol/L group. While the relative risk of end-organ damage within 24 hours was higher (5.5; 95% CI,1.9–16) in the hyperlactatemia group, having a serum lactate <4 mmol/L did not rule out a seriously septic child, suggesting that practitioners should not use screening serum lactates alone to risk-stratify pediatric patients suspected of having sepsis.