| 1. |
- Engquist, Henrik, et al.
(author)
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CBF changes and cerebral energy metabolism during hypervolemia, hemodilution, and hypertension therapy in patients with poor-grade subarachnoid hemorrhage
- 2021
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In: Journal of Neurosurgery. - : Journal of Neurosurgery Publishing Group (JNSPG). - 0022-3085 .- 1933-0693. ; 134:2, s. 555-564
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Journal article (peer-reviewed)abstract
- OBJECTIVE: Despite the multifactorial pathogenesis of delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH), augmentation of cerebral blood flow (CBF) is still considered essential in the clinical management of DCI. The aim of this prospective observational study was to investigate cerebral metabolic changes in relation to CBF during therapeutic hypervolemia, hemodilution, and hypertension (HHH) therapy in poor-grade SAH patients with DCI.METHODS: CBF was assessed by bedside xenon-enhanced CT at days 0–3, 4–7, and 8–12, and the cerebral metabolic state by cerebral microdialysis (CMD), analyzing glucose, lactate, pyruvate, and glutamate hourly. At clinical suspicion of DCI, HHH therapy was instituted for 5 days. CBF measurements and CMD data at baseline and during HHH therapy were required for study inclusion. Non-DCI patients with measurements in corresponding time windows were included as a reference group.RESULTS: In DCI patients receiving HHH therapy (n = 12), global cortical CBF increased from 30.4 ml/100 g/min (IQR 25.1–33.8 ml/100 g/min) to 38.4 ml/100 g/min (IQR 34.2–46.1 ml/100 g/min; p = 0.006). The energy metabolic CMD parameters stayed statistically unchanged with a lactate/pyruvate (L/P) ratio of 26.9 (IQR 22.9–48.5) at baseline and 31.6 (IQR 22.4–35.7) during HHH. Categorized by energy metabolic patterns during HHH, no patient had severe ischemia, 8 showed derangement corresponding to mitochondrial dysfunction, and 4 were normal. The reference group of non-DCI patients (n = 11) had higher CBF and lower L/P ratios at baseline with no change over time, and the metabolic pattern was normal in all these patients.CONCLUSIONS: Global and regional CBF improved and the cerebral energy metabolic CMD parameters stayed statistically unchanged during HHH therapy in DCI patients. None of the patients developed metabolic signs of severe ischemia, but a disturbed energy metabolic pattern was a common occurrence, possibly explained by mitochondrial dysfunction despite improved microcirculation.
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| 2. |
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| 3. |
- Marklund, Niklas, et al.
(author)
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Monitoring of brain interstitial total tau and beta amyloid proteins by microdialysis in patients with traumatic brain injury.
- 2009
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In: Journal of neurosurgery. - 0022-3085 .- 1933-0693. ; 110:6, s. 1227-37
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Journal article (peer-reviewed)abstract
- OBJECT: Damage to axons contributes to postinjury disabilities and is commonly observed following traumatic brain injury (TBI). Traumatic brain injury is an important environmental risk factor for the development of Alzheimer disease (AD). In the present feasibility study, the aim was to use intracerebral microdialysis catheters with a high molecular cutoff membrane (100 kD) to harvest interstitial total tau (T-tau) and amyloid beta 1-42 (Abeta42) proteins, which are important biomarkers for axonal injury and for AD, following moderate-to-severe TBI.METHODS: Eight patients (5 men and 3 women) were included in the study; 5 of the patients had a focal/mixed TBI and 3 had a diffuse axonal injury (DAI). Following the bedside analysis of the routinely measured energy metabolic markers (that is, glucose, lactate/pyruvate ratio, glycerol, and glutamate), the remaining dialysate was pooled and two 12-hour samples per day were used to analyze T-tau and Abeta42 by enzyme-linked immunosorbent assay from Day 1 up to 8 days postinjury.RESULTS: The results show high levels of interstitial T-tau and Abeta42 postinjury. Patients with a predominantly focal lesion had higher interstitial T-tau levels than in the DAI group from Days 1 to 3 postinjury (p < 0.05). In contrast, patients with DAI had consistently higher Abeta42 levels when compared with patients with focal injury.CONCLUSIONS: These results suggest that monitoring of interstitial T-tau and Abeta42 by using microdialysis may be an important tool when evaluating the presence and role of axonal injury following TBI.
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| 4. |
- Rostami, Elham, 1979-, et al.
(author)
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Early low cerebral blood flow and high cerebral lactate : prediction of delayed cerebral ischemia in subarachnoid hemorrhage
- 2018
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In: Journal of Neurosurgery. - 0022-3085 .- 1933-0693. ; 128:6, s. 1762-1770
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Journal article (peer-reviewed)abstract
- OBJECTIVE Delayed cerebral ischemia (DCI) following subarachnoid hemorrhage (SAH) is one of the major contributors to poor outcome. It is crucial to be able to detect early signs of DCI to prevent its occurrence. The objective of this study was to determine if low cerebral blood flow (CBF) measurements and pathological microdialysis parameters measured at the bedside can be observed early in patients with SAH who later developed DCI. METHODS The authors included 30 patients with severe SAH. The CBF measurements were performed at Day 0-3 after disease onset, using bedside xenon-CT. Interstitial glucose, lactate, pyruvate, glycerol, and glutamate were measured using microdialysis. RESULTS Nine of 30 patients developed DCI. Patients with DCI showed significantly lower global and regional CBF, and lactate was significantly increased in these patients. A high lactate/pyruvate ratio was also detected in patients with DCI. CONCLUSIONS Early low CBF measurements and a high lactate and lactate/pyruvate ratio may be early warning signs of the risk of developing DCI. The clinical value of these findings needs to be confirmed in larger studies.
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| 5. |
- Samuelsson, Carolina, et al.
(author)
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Relationship between intracranial hemodynamics and microdialysis markers of energy metabolism and glutamate-glutamine turnover in patients with subarachnoid hemorrhage
- 2009
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In: Journal of Neurosurgery. - 0022-3085 .- 1933-0693. ; 111:5, s. 910-915
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Journal article (peer-reviewed)abstract
- OBJECT: The aim of this study was to explore the relationship between hemodynamics (intracranial and systemic) and brain tissue energy metabolism, and between hemodynamics and glutamate (Glt)-glutamine (Gln) cycle activity. METHODS: Brain interstitial levels of lactate, pyruvate, Glt, and Gln were prospectively monitored in the neurointensive care unit for more than 3600 hours using intracerebral microdialysis in 33 patients with subarachnoid hemorrhage (SAH). Intracranial pressure (ICP), mean arterial blood pressure, and cerebral perfusion pressure (CPP) were recorded using a digitalized system. RESULTS: Interstitial Gln and pyruvate correlated with CPP (r = 0.25 and 0.24, respectively). Intracranial pressure negatively correlated with Gln (r = -0.29) and the Gln/Glt ratio (r = -0.40). Levels of Gln and pyruvate and the Gln/Glt ratio were higher and levels of Glt and lactate and the lactate/pyruvate ratio were lower during periods of decreased ICP ( 10 mm Hg). In 3 patients, a poor clinical condition was attributed to high ICP levels (range 15-25 mm Hg). When CSF drainage was increased and the ICP was lowered to 10 mm Hg, there was an instantaneous sharp increase in interstitial Glt and pyruvate in these 3 patients. CONCLUSIONS: Increasing interstitial Gln and pyruvate levels appear to be favorable signs associated with improved CPP and low ICP. The authors suggest that this pattern indicates an energy metabolic situation allowing augmented astrocytic energy metabolism with accelerated Glt uptake and Gln synthesis. Moreover, their data raised the question of whether patients with SAH and moderately elevated ICP (15-20 mm Hg) would benefit from CSF drainage at lower pressure levels than what is usually indicated in current clinical protocols.
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| 6. |
- Samuelsson, Carolina, et al.
(author)
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Response
- 2009
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In: Journal of Neurosurgery. - 0022-3085 .- 1933-0693. ; 111:5, s. 908-909
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Journal article (peer-reviewed)
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| 7. |
- Zetterling, Maria, et al.
(author)
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Relation between brain interstitial and systemic glucose concentrations after subarachnoid hemorrhage
- 2011
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In: Journal of Neurosurgery. - 0022-3085 .- 1933-0693. ; 115:1, s. 66-74
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Journal article (peer-reviewed)abstract
- Object. The aim in the present investigation was to study the relation between brain interstitial and systemic blood glucose concentrations during the acute phase after subarachnoid hemorrhage (SAH). The authors also evaluated the effects of insulin administration on local brain energy metabolism. Methods. Nineteen patients with spontaneous SAH were prospectively monitored with intracerebral microdialysis (MD). The relation between plasma glucose and MD-measured interstitial brain glucose concentrations as well as the temporal pattern of MD glucose, lactate, pyruvate, glutamate, and glycerol was studied for 7 days after SAH. Using a target plasma glucose concentration of 5-10 mmol/L, the effect of insulin injection was also evaluated. Results. The mean (+/- SD) correlation coefficient between plasma glucose and MD glucose was 0.27 +/- 0.27 (p = 0.0005), with a high degree of individual variation. Microdialysis glucose, the MD/plasma glucose ratio, and MD glutamate concentrations decreased in parallel with a gradual increase in MD pyruvate and MD lactate concentrations. There were no significant changes in the MD L/P ratio or MD glycerol levels. Insulin administration induced a decrease in MD glucose and MD pyruvate. Conclusions. After SAH, there was a positive correlation between plasma and MD glucose concentrations with a high degree of individual variation. A gradual decline in MD glucose and the MD/plasma glucose ratio and an increase in MD pyruvate and MD lactate concentrations during the 1st week after SAH suggest a transition to a hyperglycolytic state with increased cerebral glucose consumption. The administration of insulin was related to a lowering of MD glucose and MD pyruvate, often to low levels even though plasma glucose values remained above 6 mmol/L. After SAH, the administration of insulin could impede the glucose supply of the brain.
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| 8. |
- Zetterling, Maria, 1966-, et al.
(author)
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Relation between brain interstitial and systemic glucose levels after subarachnoid hemorrhage
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In: Journal of Neurosurgery. - 0022-3085 .- 1933-0693.
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Journal article (peer-reviewed)abstract
- Objects: The optimal blood glucose level after acute brain injury is not known. The aim of the present investigation was to study the relation between brain interstitial and systemic blood glucose levels during the acute phase after SAH. We also studied the effects of insulin administration on local brain energy metabolism. Methods: 19 patients with spontaneous SAH were monitored with intracerebral microdialysis (MD). The relation between plasma (P)-glucose and interstitial MD-glucose levels and the temporal pattern of MD-metabolites was studied seven days after SAH. With a target P-glucose of 5-10 mmol/L, the effect of insulin injection on brain energy metabolites (MD-glucose, lactate, pyruvate) and glutamate was evaluated. Results: The mean correlation coefficient between P-glucose and MD-glucose was 0.27 ± 0.27, (p=0.0005) with a high degree of individual variation. MD-glucose, MD/P-glucose ratio and MD-glutamate levels decreased in parallel with a gradual increase in MD-pyruvate and MD-lactate levels. There were no significant changes of MD-L/P ratio or MD-glycerol. Insulin administration induced a statistically significant decrease in MD-glucose and MD-pyruvate. Conclusion: After SAH, there was a positive correlation between P-glucose and MD-glucose levels with a high degree of individual variation. A gradual decline of MD-glucose and MD/P-glucose ratio and an increase of MD-pyruvate and MD-lactate levels during the first week after SAH could suggest a transition to a hyperglycolytic state with increased cerebral glucose consumption. Administration of insulin was related to lowering of MD-glucose and MD-pyruvate, often to critically low levels even though plasma glucose values remained above 6 mmol/L. Thus, P-glucose should not be low in the acute phase after SAH and administration of insulin should be done with caution, even more crucial when the cerebral glucose metabolism has recovered and an increased energy demand is developing in the injured, repairing brain.
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