Regional Cerebral Metabolism Changes After Brain Injury: A Microdialysis Study

Objective:to study the changes of Glu,Lac,Pyru,Gly, in the extracellular fluid with craniocerebral trauma with microdialysis on biochemical metabolism. To explore microdialysis technology in monitoring brain damage local biochemical substances and study meaning of the changing of glucose and lactic acid change meaning in local extracellular fluid (ECF).Methods:Catheters for microdialysis were punctured into semi-dark band in the cerebral traumatic foci.relatively normal cerebral tissues respective so as to collect fluid for microdialysis,with perfusion speed of 0.3ul/min. One cube of fluid for microdialysis was obtained every one hour. The average collection time in 10 patients was 72h.The collected fluid was tested by biochemical instruments for examing the leves of Glu,Lac,Pyru and Gly. Results:Through the microdialysis method for detection of extracellular fluid concentrations of Glu and Lac was observed after brain injury Glu decreased with decreased significantly compared to the 1st hours after injury,32 hours reached a peak, followed by a gradual pick-up in Lac. Content after the injury and the changes in Glu contrary. However, slower changes. ECF brain Glu and Lac in the content of the degree of change and injury, the more damage the more obvious changes in weight, longer duration can be used as to determine the extent of injury and brain edema an important basis.Glycerin changes was similar with lactic acid, postoperative rises,32h-44h peaked, and fell, and be relevant of the variations and damage degree.Pyruvate change is similar with glucose change trend, postoperative declined obviously, and postoperative 27h～33h peaked then picks up, GCS score was lower, and change has the bigger fluctuation.Conclusion:1. Microdialysis technique is a minimally invasive, safe, new monitoring tools, to partial brain damage and biochemical changes in the material content of the continuing monitoring of the metabolism.2 After brain injury decreased ECF glucose, lactic acid content increased, both were contrary to the dynamic changes 3. Monitoring after brain injury in ECF glycerol increased slowly first and decreased later.4 Monitoring after brain injury in ECF pyruvate decreased slowly first and increased later.