The relationship between lactate, base excess and mortality in paediatric intensive care

Abstract

Aims & Objectives: High lactate and base excess (BE) values are associated with higher mortality in adult and paediatric intensive care units. The absolute value of BE is currently used in the calculation of Paediatric Index of Mortality (PIM). We investigated the association between lactate and BE and determined which more accurately predicts mortality. Methods Data were abstracted from the UK and Republic of Ireland Paediatric Intensive Care Audit Network (PICANet) and the Australian and New Zealand Paediatric Intensive Care Registry (ANZPICR), for all admissions between 1st January 2012 and 31st December 2015 that had both a lactate and BE measurement (N=59,915) obtained within one hour of PIC admission. Spearman correlation coefficient, univariate logistic regression models and generalized additive modelling (GAM) functions were used. Results Lactate is moderately negatively correlated with BE (rho=-0.20 p<0.001) (Figure 1) and that correlation becomes stronger for those that died (rho=-0.62 p<0.001). High negative BE values are associated with higher mortality (OR=1.17, 95% CI (1.16, 1.18) than high positive BE values (OR=1.01, 95% CI (0.99, 1.02) (Figure 2). There is a stronger relationship between lactate and mortality than BE per unit increase (OR=1.32, 95% CI (1.31, 1.34)) (Figures 2 & 3), and a higher area under the Receiver Operating Characteristic (ROC) curve for lactate than BE (0.746 vs 0.669). Conclusions Lactate is a better predictor of mortality than BE. High negative BE values have a higher mortality trajectory than high positive values, suggesting that alternative approaches to modelling should be examined. (Figure prsented).L6238155052018-09-13 <br />