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Title: The application of microdialysis to the human brain
Author: Hutchinson, P. J. A.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2001
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The objective of the work discussed in this thesis was to study the cerebral chemistry of neurosurgical patients using microdialysis in order to enhance our understanding of the pathophysiology of acute brain injury due to trauma and subarachnoid haemorrhage. The following observations were made: 1. Microdialysis can be safely performed in theatre and intensive care; 2. Catheter transmission into the brain was achieved using a new cranial access device; 3. Two adjacent, identical catheters showed good reproducibility. Perfusate Ca++ concentration and sample freezing did not affect glucose, lactate, pyruvate and glutamate levels. Catheter length did affect levels. A modification of the extrapolation to zero flow method showed that the recovery of these substances (i.e. the microdialysis concentration as a % of the true extracellular concentration) was approximately 70% at 0.3 μl/min. Glutamate levels from an on-line analyser (CMA600) correlated well with High Performance Liquid Chromatography; 4. Combining microdialysis with Positron Emission Tomography was feasible, although logistically complex, and revealed a good relationship between the lactate/pyruvate (L/P) ratio and oxygen extraction fraction. Blood flow did not correlate significantly with the results of microdialysis. Hyperventilation produced a reduction in cerebral glucose but this did not translate into elevation of the L/P ratio or glutamate levels; 5. In aneurysm surgery, prolonged temporary clipping (greater than 3 min) was associated with reduction in brain oxygen and elevation of the L/P ratio.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available