Relationship Between Systemic and Cerebral Microdialysate Glucose in Patients With Severe Acute Brain Injury-A Retrospective Study.

BACKGROUND

Markers of cerebral metabolism measured by microdialysis (CMD) may warn clinicians of impending neuroworsening in patients with severe acute brain injury. This retrospective study investigated the relationship between systemic glucose levels and microdialysate glucose (CMD-glucose) in patients with severe traumatic brain injury (TBI) or aneurysmal subarachnoid haemorrhage (SAH).

METHODS

We retrospectively investigated patients who underwent CMD. Linear regression and correlation analysis between temporally matched values of systemic and CMD-glucose were performed. Disease severity was dichotomized using the Glasgow Coma Scale score (GCS) at admission, and patient outcome at 6 months was dichotomized using the modified Rankin Scale.

RESULTS

Data was available from 133 patients, of which 75 had SAH and 58 had TBI. The R suggested that systemic glucose levels explained 31% (95% CI: 14-39) of CMD-glucose variation in SAH patients and 15% (95% CI: 5-45) in TBI patients. In a linear regression model, CMD-glucose increased by 0.16 (95% CI: 0.16-0.17) for patients with SAH and 0.17 (95% CI: 0.16-0.18) mmol/L for patients with TBI for every 1 mmol/L increase in systemic glucose. Furthermore, both systemic and CMD-glucose decreased with increasing time from ictus. We found no association between CMD-glucose and disease severity or functional outcome.

CONCLUSION

In this retrospective analysis of patients with severe acute brain injury undergoing intracerebral microdialysis, changes in systemic glucose contributed to changes in CMD-glucose with no relation to functional outcome.

EDITORIAL COMMENT

This study assessed microdialysis-derived brain tissue extracellular glucose levels, analysed together with serum glucose levels measured at the same time; this was in patients with acute brain injury with sampling in the less injured cerebral hemisphere. Findings demonstrated that there were predictable changes in microdialysate glucose levels when serum glucose levels changed. Neither of these glucose levels was associated with functional outcomes.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT06302244.