The Role of Glycerol-Containing Drugs in Cerebral Microdialysis: A Retrospective Study on the Effects of Intravenously Administered Glycerol

Maximilian Peter Forssten,David W Nelson,Eric Peter Thelin,Bo-Michael Bellander

doi:10.1007/s12028-018-0643-4

Abstract

BackgroundCerebral microdialysis (CMD) is a valuable tool for monitoring compounds in the cerebral extracellular fluid (ECF). Glycerol is one such compound which is regarded as a marker of cell membrane decomposition. Notably, in some acutely brain-injured patients, CMD-glycerol levels rise without any other apparent indication of cerebral deterioration. The aim of this study was to investigate whether this could be due to an association between CMD-glycerol levels and the administration of glycerol-containing drugs.MethodsMicrodialysis data were retrospectively retrieved from the hospital’s intensive care unit patient data management system (PDMS). All patients who were monitored with CMD for ≥ 96 h were included. Administered drug doses were retrieved from the PDMS and converted to exact doses of glycerol. Cross-correlation analyses were performed between the free, metabolized as well as total administered dose of glycerol and the detrended and differenced CMD-glycerol concentration. These analyses were repeated for two sets of subgroups based upon the individual catheter’s graphical trend and its location in relation to the lesion.ResultsThere was no significant correlation between the differenced CMD-glycerol levels and drug-administered glycerol. Furthermore, there was no significant correlation between CMD-glycerol and catheter location or graphical trend. However, if the CMD-glycerol levels were detrended, significant but clinically non-relevant correlations were identified (maximum correlation coefficient of 0.1 (0.04–0.15, 95% CI) at a lag of 7 h using the total administered dose of glycerol).ConclusionsGlycerol-containing drugs routinely administered intravenously in the clinical setting appear to have a minimal and clinically insignificant effect on levels of glycerol in the cerebral ECF.

Highlights

Microdialysis is a technique used for monitoring the concentration of compounds within the extracellular fluid (ECF) [1]
Correlation Between administered dose of glycerol (ADG) and Cerebral microdialysis (CMD)‐Glycerol Raw CMD data did not show any correlation between the ADG and CMD-glycerol, but as raw CMD data display a high degree of autocorrelation [12], we chose to perform a detrended and differenced analysis
Free ADG and Detrended CMD‐Glycerol (Trauma Patients; n = 102) Cross-correlation analysis showed statistically significant results for all lag values within the specified range where the detrended CMD-glycerol lags the free ADG (Lag − 20 → − 1) and where there was no lag (Lag 0), that is from the time of intravenous administration up to 20 h later (Fig. 4)

Summary

Introduction

Microdialysis is a technique used for monitoring the concentration of compounds within the extracellular fluid (ECF) [1]. Cerebral microdialysis (CMD) is a valuable tool for monitoring compounds in the cerebral extracellular fluid (ECF) Glycerol is one such compound which is regarded as a marker of cell membrane decomposition. Cross-correlation analyses were performed between the free, metabolized as well as total administered dose of glycerol and the detrended and differenced CMD-glycerol concentration. These analyses were repeated for two sets of subgroups based upon the individual catheter’s graphical trend and its location in relation to the lesion. Conclusions: Glycerol-containing drugs routinely administered intravenously in the clinical setting appear to have a minimal and clinically insignificant effect on levels of glycerol in the cerebral ECF.

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