Intracerebral Microdialysis in Clinical Practice: Baseline Values for Chemical Markers during Wakefulness, Anesthesia, and Neurosurgery

Reinstrup, Peter; Ståhl, Nils; Mellergård, Pekka; Uski, Tore; Ungerstedt, Urban; Nordström, Carl‐Henrik

doi:10.1097/00006123-200009000-00035

Cited by 213 publications

(272 citation statements)

References 31 publications

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“…We defined an 'increase in Glt' when the concentration of Glt was higher in all the 'high L/P samples' as compared with the preceding Glt baseline concentration. In addition, the interstitial Glt levels should reach above the normal upper reference limit (32 mmol/L; Reinstrup et al, 2000) to be classified as an 'increase'. For Gln, it is currently less clear what to regard as a normal interstitial Gln concentration.…”

Section: Analysis Statistics and Presentation Of Datamentioning

confidence: 99%

Cerebral Glutamine and Glutamate Levels in Relation to Compromised Energy Metabolism: A Microdialysis Study in Subarachnoid Hemorrhage Patients

Samuelsson

Hillered

Zetterling

et al. 2007

J Cereb Blood Flow Metab

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Astrocytic glutamate (Glt) uptake keeps brain interstitial Glt levels low. Within the astrocytes Glt is converted to glutamine (Gln), which is released and reconverted to Glt in neurons. The Glt-Gln cycle is energy demanding and impaired energy metabolism has been suggested to cause low interstitial Gln/Glt ratios. Using microdialysis (MD) measurements from visually noninjured cortex in 33 neurointensive care patients with subarachnoid hemorrhage, we have determined how interstitial Glt and Gln, as a reflection of the Glt-Gln cycle turnover, relate to perturbed energy metabolism. A total of 3703 hourly samples were analyzed. The lactate/pyruvate (L/P) ratios correlated to the Gln/Glt ratios (r = À0.66), but this correlation was not stronger than the correlation between L/P and Glt (r = 0.68) or the correlation between lactate and Glt (r = 0.65). A novel observation was a linear relationship between interstitial pyruvate and Gln (r = 0.52). There were 13 periods (404 h) of 'energy crisis', defined by L/P ratios above 40. All were associated with high interstitial Glt levels. Periods with L/P ratios above 40 and low pyruvate levels were associated with decreased interstitial Gln levels, suggesting ischemia and failing astrocytic Gln synthesis. Periods with L/P ratios above 40 and normal or high pyruvate levels were associated with increased interstitial Gln levels, which may represent an astrocytic hyperglycolytic response to high interstitial Glt levels. The results imply that moderately elevated L/P ratios cannot always be interpreted as failing energy metabolism and that interstitial pyruvate levels may discriminate whether or not there is sufficient astrocytic capacity for Glt-Gln cycling in the brain.

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Section: Analysis Statistics and Presentation Of Datamentioning

confidence: 99%

Cerebral Glutamine and Glutamate Levels in Relation to Compromised Energy Metabolism: A Microdialysis Study in Subarachnoid Hemorrhage Patients

Samuelsson

Hillered

Zetterling

et al. 2007

J Cereb Blood Flow Metab

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“…Since its first introduction by Ungerstedt and colleagues (Ungerstedt and Pycock, 1974;Tossman et al, 1983), the technique of cerebral microdialysis has yielded important information in a remarkable variety of fields within basic and clinical neuroscience (Hillered et al, 1990;Reinstrup et al, 2000). The many published reports of assays of brain microdialysate from patients with head injury have until now relied on data from catheters located in cerebral white matter, with dialysate aliquots typically integrated over periods of 60 mins but occasionally over 20 mins (Hutchinson et al, 2002), and assayed most commonly for glucose, lactate, pyruvate, glycerol, and glutamate.…”

Section: Rapid Sampling Of Microdialysate From Peri-lesion Cerebral Cmentioning

confidence: 99%

Dynamic Changes in Brain Glucose and Lactate in Pericontusional Areas of the Human Cerebral Cortex, Monitored with Rapid Sampling On-Line Microdialysis: Relationship with Depolarisation-Like Events

Parkin

Hopwood

Jones

et al. 2005

J Cereb Blood Flow Metab

137

114

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The pathophysiology of peri-lesion boundary zones in acute brain injury is highly dynamic, and it is now clear that spreading-depression-like events occur frequently in areas of cerebral cortex adjacent to contusions in the injured human brain. An automated method to assay microdialysate from peri-lesion cerebral cortex in 11 patients with intracranial haematomas requiring surgery was used. Perfusate (2 lL/min) flowed directly into a flow-injection system for assay of glucose and lactate at intervals typically of 30 secs each. Four channels of electrocorticogram (ECoG) were recorded from a subdural strip adjacent to the catheter. Several patterns of change in metabolites were identified in different time domains. Overall, the number of transient lactate events was significantly correlated with the number of glucose events (r 2 ¼ 0.48, P ¼ 0.027, n ¼ 10). Progressive reduction in dialysate glucose was very closely correlated with the aggregate number of ECoG events (r 2 ¼ 0.76, P ¼ 0.0004, n ¼ 11). It is proposed that the recently documented adverse impact of low dialysate glucose on clinical outcome may be because of recurrent, spontaneous spreadingdepression-like events in the perilesion cortex.

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“…However, the lactate/pyruvate ratio showed no significant difference between the two groups. The extracellular concentration of glucose was lower and the lactate/pyruvate ratio was higher than the normal range 25) in both groups. Within the intensive care period of 7 days, the mean ICP remained in the range of º20 mmHg (Fig.…”

mentioning

confidence: 64%

Lower Extracellular Glucose Level Prolonged in Elderly Patients With Severe Traumatic Brain Injury: A Microdialysis Study

Yokobori

Watanabe

Matsumoto

et al. 2011

Neurol. Med. Chir.(Tokyo)

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Age may be an independent predictor of outcomes in traumatic brain injury (TBI), but the causes of the poor outcomes in elderly patients remain unclear. To clarify the differences between elderly and young patients with TBI, brain metabolism parameters were monitored with the microdialysis method in 30 patients with severe TBI (Glasgow Coma Scale scores 3-8). The microdialysis probe was inserted in the penumbra area of the brain and extracellular levels of glucose, glutamate, glycerol, lactate, and pyruvate were measured hourly for the initial 168 hours (7 days) after operation. The lactate/pyruvate ratio, which is considered to be a good indicator of neuronal ischemia, was also calculated. The patients were divided into the elderly group aged 65 years or older and the young group aged less than 65 years, and the biochemical markers were compared daily between these two groups. The value of extracellular glucose concentration was significantly lower in the elderly group than in the young group, and continued until the 7th day after injury. Moreover, the lactate/pyruvate ratio peaked on the 5th day after injury in the elderly group, later than in the young group. We concluded that neural vulnerability persisted longer in elderly patients than in young patients with TBI, and this should be considered to prevent the occurrence of additional secondary brain injury.

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Intracerebral Microdialysis in Clinical Practice: Baseline Values for Chemical Markers during Wakefulness, Anesthesia, and Neurosurgery

Abstract: The study provides human baseline levels for biochemical markers that can presently be measured at the bedside during neurointensive care. In addition, some changes that occurred under varying physiological conditions are described.

Cited by 213 publications

References 31 publications

Cerebral Glutamine and Glutamate Levels in Relation to Compromised Energy Metabolism: A Microdialysis Study in Subarachnoid Hemorrhage Patients

Cerebral Glutamine and Glutamate Levels in Relation to Compromised Energy Metabolism: A Microdialysis Study in Subarachnoid Hemorrhage Patients

Dynamic Changes in Brain Glucose and Lactate in Pericontusional Areas of the Human Cerebral Cortex, Monitored with Rapid Sampling On-Line Microdialysis: Relationship with Depolarisation-Like Events

Lower Extracellular Glucose Level Prolonged in Elderly Patients With Severe Traumatic Brain Injury: A Microdialysis Study

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