Lactate Measurements and Their Association With Mortality in Pediatric Severe Sepsis in India: Evidence That 6-Hour Level Performs Best

Purpose: To investigate association of static and dynamic lactate indices with early mortality (within 48 hours of admission), as well as need for vasopressors and mechanical ventilation in pediatric severe sepsis/shock. To explore optimal cutoffs of lactate indices. We hypothesized that dynamic indices are superior to static indices in predicting early mortality.

Methods: This prospective cohort study involved children (aged <14 years) admitted in emergency department, tertiary care teaching hospital in North India with severe sepsis/shock (2015-2016). Arterial lactate was measured at admission (X0) and after 6 hours (X6). Primary outcome of the measurement was early mortality. Association between lactate indices- lactate at 0 hours (Lac0), lactate after 6 hours (Lac6), time-weighted average (LacTW), delta (ΔLac), clearance (LacCl%) and early mortality, need for vasopressors, and mechanical ventilation-was assessed using Student t test/Mann-Whitney test. Area under the receiver operating characteristic curve (AUROC) for early mortality deduced for all lactate indices and compared with reference (Lac0). Optimal cutoffs (maximizing both sensitivity and specificity) and their positive predictive value (PPV) and negative predictive value (NPV) were determined.

Results: During the study period, 116 children were assessed. Septic shock was present at admission in 56.9% children; 50% of children died during the next 48 hours. Lac0, Lac6, and LacTW were significantly higher, and LacCl% was lower in nonsurvivors versus survivors (all P < .001). Lac6 (0.837 [0.76-0.91]) had significantly higher AUROC (95% confidence interval) than Lac0 (0.77; P = .03). Abnormal lactate metrics (higher Lac0, Lac6, LacTW, and lower LacCl%) were associated with vasopressors need and mechanical ventilation. On logistic regression, Lac6 emerged as an independent predictor of early mortality as well as vasopressor and mechanical ventilation need. The optimal cutoff of Lac6 for identifying early mortality with good sensitivity, specificity, PPV, and NPV was ≥2.65 (76, 85, 83, 78).

Conclusions: Lactate6 is the best marker associated with early mortality and higher level of care in severe sepsis/septic shock in resource-poor regions.