Continuous lactate monitoring in critically ill patients using microdialysis

Abstract

Introduction: Blood lactate is a strong predictor of mortality in critically ill patients. Its monitoring implies repeated measurements. The EIRUS™ system (Maquet Critical Care AB, 17154, Solna, Sweden) is a new device allowing continuous lactate monitoring by intravascular micro dialysis. The present study aimed at assessing the accuracy of the EIRUS™ system in critically ill patients with circulatory failure.

Methods: An observational cohort study was conducted in Nîmes University Hospital. Eligible patients were those with circulatory failure in which a specific central venous access was put in place by the physician in charge, allowing continuous lactate measurement by the EIRUS™ system. Lactate measurements obtained by the system were compared to lactate from arterial blood samples at H4 and H8 from the calibration, during the first 48hours of shock.

Results: In all, 28 patients were included providing 244 pairs of measures. The Bland-Altman analysis showed a bootstrapped mean bias at H4 of 0.05 and 95% limits of agreement of -0.9 to 1.0mmol/L. At H8 the mean bias was 0.06 and 95% limits of agreement -1.1 to 1.2mmol/L. The global trend agreement [95% CI] for a pre-specified arbitrary threshold of 1mmol/L, defining clinically significant variations, between H0 and H4 and H4 and H8 was 91.6% [85.1; 95.9] and 89.5% [82.3; 94.4], respectively.

Conclusion: The EIRUS™ device provided an overall accurate measurement of lactate in critically ill patients with circulatory failure. Detection of lactate variations over time is less precise and technical issues may limit its clinical use.

Keywords: Intensive care unit; Lactate; Micro dialysis; Monitoring; Shock.