Usefulness of base deficit in the assessment of serum lactate levels in critically ill patients on mechanical ventilation

Abstract

Background/aim: Acid-base disturbances are common in critically ill patients. Some of the most commonly used markers of metabolic acidosis are base defi cit and lactate. Th e aim of this study was to evaluate the correlation between base defi cit and serum lactate and the utility of base defi cit in the assessment of serum lactate levels in critically ill patients on mechanical ventilation. Methods: Th is study was designed as a retrospective, analytical study. We reviewed all arterial gas analyses (base defi cit and lactate levels) of patients on mechanical ventilation. Th e correlation between base defi cit and lactate was assessed by calculation of the Pearson correlation coeffi cient (r) and coeffi cient of determination (R 2). Receiver operating characteristic (ROC) curves were created for base defi cit to detect the presence of hyperlactatemia. Th e SPSS 12.0 software package (Chicago, Illinois) was used for statistical analyses. Results: One hundred forty-two patients participated in the study: including survivors (n=68) and non-survivors (n=74). Th e mean value of base defi cit was 0.512 ± 6.10 mmol/L, and the mean value of serum lactate was 2.04 ± 2.07 mmol/L. Th ere was no diff erence in lactate and base defi cit values between the groups (p=0.101, p=0.106, respectively). Hyperlactatemia was observed in 44 patients (30.98 %). In ROC curve analysis, the area under the curve for base defi cit to detect hyperlactatemia was 0.527. Conclusion: Th is study indicates that base defi cit is not an appropriate marker in the evaluation of real serum lactate values.