| 1. |
- Covaciu, Lucian, et al.
(författare)
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Intranasal selective brain cooling in pigs
- 2008
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Ingår i: Resuscitation. - : Elsevier BV. - 0300-9572 .- 1873-1570. ; 78:1, s. 83-88
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Special clinical situations where general hypothermia cannot be recommended but can be a useful treatment demand a new approach, selective brain cooling. The purpose of this study was to selectively cool the brain with cold saline circulating in balloon catheters introduced into the nasal cavity in pigs. MATERIAL AND METHODS: Twelve anaesthetised pigs were subjected to selective cerebral cooling for a period of 6 h. Cerebral temperature was lowered by means of bilaterally introduced nasal balloon catheters perfused with saline cooled by a heat exchanger to 8-10 degrees C. Brain temperature was measured in both cerebral hemispheres. Body temperature was measured in rectum, oesophagus and the right atrium. The pigs were normoventilated and haemodynamic variables were measured continuously. Acid-base and electrolyte status was measured hourly. RESULTS: Cerebral hypothermia was induced rapidly and within the first 20 min of cooling cerebral temperature was lowered from 38.1+/-0.6 degrees C by a mean of 2.8+/-0.6 to 35.3+/-0.6 degrees C. Cooling was maintained for 6 h and the final brain temperature was 34.7+/-0.9 degrees C. Concomitantly, the body temperature, as reflected by oesophageal temperature was decreased from 38.3+/-0.5 to 36.6+/-0.9 degrees C. No circulatory or metabolic disturbances were noted. CONCLUSIONS: Inducing selective brain hypothermia with cold saline via nasal balloon catheters can effectively be accomplished in pigs, with no major disturbances in systemic circulation or physiological variables. The temperature gradients between brain and body can be maintained for at least 6 h.
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| 3. |
- Marklund, Niklas, et al.
(författare)
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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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Ingår i: Journal of neurosurgery. - 0022-3085 .- 1933-0693. ; 110:6, s. 1227-37
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Tidskriftsartikel (refereegranskat)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. |
- Neumann, JO, et al.
(författare)
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The use of hyperventilation theraphy after traumatic brain injury in Europe : an analysis of the BrainIT database
- 2008
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Ingår i: Intensive Care Medicine. - : Springer Science and Business Media LLC. - 0342-4642 .- 1432-1238. ; 34:9, s. 1676-1682
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Tidskriftsartikel (refereegranskat)abstract
- Objective To assess the use of hyperventilation and the adherence to Brain Trauma Foundation-Guidelines (BTF-G) after traumatic brain injury (TBI). Setting Twenty-two European centers are participating in the BrainIT initiative. Design Retrospective analysis of monitoring data. Patients and participants One hundred and fifty-one patients with a known time of trauma and at least one recorded arterial blood–gas (ABG) analysis. Measurements and results A total number of 7,703 ABGs, representing 2,269 ventilation episodes(VE) were included in the analysis. Related minute-by-minute ICP data were taken from a 30 min time window around each ABG collection. Data are given as mean with standard deviation. (1) Patients without elevated intracranial pressure (ICP) (\20 mmHg) manifested a statistically significant higher PaCO2(36 ± 5.7 mmHg) in comparison to patients with elevated ICP(C20 mmHg; PaCO2:34 ± 5.4 mmHg, P\0.001). (2) Intensified forced hyperventilation(PaCO2 B 25 mmHg) in the absence of elevated ICP was found in only 49VE (2%). (3) Early prophylactic hyperventilation (\24 h after TBI;PaCO2 B 35 mmHg,ICP\20 mmHg) was used in 1,224VE (54%). (4) During forced hyperventilation(PaCO2 B 30 mmHg), simultaneous monitoring of brain tissue pO2 or SjvO2 was used in only 204 VE (9%). Conclusion While overall adherence to current BTF-Gseems to be the rule, its recommendations on early prophylactic hyperventilation as well as the use of additional cerebral oxygenation monitoring during forced hyperventilation are not followed in this sample of European TBI centers. Descriptor Neurotrauma
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| 5. |
- Ågren Wilsson, Aina, 1958-
(författare)
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On the pathophysiology of idiopathic adult hydrosephalus syndrome : energy metabolism, protein patterns, and intracranial pressure
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The symptoms in Idiopathic Adult Hydrocephalus Syndrome (IAHS) – gait disturbance, incontinence, and cognitive deficit – correlate anatomically to neuronal dysfunction in periventricular white matter. The pathophysiology is considered to include a cerebrospinal fluid (CSF) hydrodynamic disturbance, including pressure oscillations (“B waves”), in combination with cerebrovascular disease. IAHS and Subcortical Arteriosclerotic Encephalopathy (SAE) show clinical similarities, which constitutes a diagnostic problem. The aim of this thesis was to investigate biochemical markers in CSF, possibly related to the pathophysiology, and their usefulness in diagnosis, to investigate the effect of ICP changes on glucose supply and metabolism in periventricular deep white matter, and to present criteria for objective, computerised methods for evaluating the content of B waves in an intracranial pressure (ICP) registration. CSF samples from 62 IAHS patients, 26 SAE patients, and 23 controls were analysed for sulfatide, total-tau (T-tau) hyperphosphorylated tau (P-tau), neurofilament protein light (NFL), and beta-amyloid-42 (Aß42). In ten IAHS patients, recordings of ICP, brain tissue oxygen tension (PtiO2), and samplings of brain extracellular fluid from periventricular white matter by way of microdialysis were performed, at rest and during a CSF infusion and tap test. Microdialysis samples were analysed for glucose, lactate, pyruvate, glutamate, glycerol, and urea. Patterns before and after spinal tap were analysed and changes from increasing ICP during the infusion test were described. The long term ICP registration was used to evaluate two computerised methods according to optimal amplitude threshold, monitoring time, and correlation to the manual visual method. In CSF, NFL was elevated in both IAHS and SAE patients, reflecting the axonal damage. In a multinominal logistic regression model, the combined pattern of high NFL, low P-tau and low Aß42 in CSF was shown to be highly predictive in distinguishing between IAHS, SAE and controls. Analysis of microdialysis samples for glucose, lactate, and pyruvate showed, in combination with PtiO2, a pattern of low-grade ischemia. After the spinal tap of CSF, the pattern changed, indicating increased glucose metabolic rate. During the infusion test, there were prompt decreases in the microdialysis values of glucose, lactate and pyruvate during ICP increase, but no sign of hypoxia. The values normalised immediately when ICP was lowered, indicating that the infusion test is not causing damage. One of the computerised methods, with an amplitude threshold set to 1 mm Hg, was shown robust in evaluating B wave content in an ICP registration. At least 5 hours registration time was needed. The highly predictive pattern of biochemical markers in CSF indicates a possibility of identifying simple tests in diagnosing and selecting patients for surgical treatment. The results of microdialysis and PtiO2 indicate low-grade ischemia in the periventricular white matter, which is ameliorated from CSF removal, and that glucose supply and metabolism are sensitive to short-term ICP elevations, thus proposing a link between ICP oscillations and symptoms from neuronal disturbance. A computerised method for evaluation of B waves is a prerequisite for evaluating the impact of pressure oscillations in the pathophysiology of IAHS.
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