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Gross AK, Norman J, Cook AM. Contemporary pharmacologic issues in the management of traumatic brain injury. J Pharm Pract 2010; 23:425-40. [PMID: 21507847 DOI: 10.1177/0897190010372322] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Traumatic brain injury (TBI) is a major cause of death and disability in the United States. While there are no pharmacotherapeutic options currently available for attenuating the neurologic injury cascade after TBI, numerous pharmacologic issues are encountered in these critically ill patients. Adequate fluid resuscitation, reversal of coagulopathy, maintenance of cerebral perfusion, and treatment of intracranial hypertension are common interventions early in the treatment of TBI. Other deleterious complications such as venous thromboembolism, extremes in glucose concentrations, and stress-related mucosal disease should be anticipated and avoided. Early provision of nutrition and prevention of drug or alcohol withdrawal are also cornerstones of routine care in TBI patients. Prevention of infections and seizures may also be helpful. Clinicians caring for TBI patients should be familiar with the pharmacologic issues typical of this vulnerable population in order to develop optimal strategies of care to anticipate and prevent common complications.
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152
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Nakamura H, Strong AJ, Dohmen C, Sakowitz OW, Vollmar S, Sué M, Kracht L, Hashemi P, Bhatia R, Yoshimine T, Dreier JP, Dunn AK, Graf R. Spreading depolarizations cycle around and enlarge focal ischaemic brain lesions. ACTA ACUST UNITED AC 2010; 133:1994-2006. [PMID: 20504874 PMCID: PMC2892938 DOI: 10.1093/brain/awq117] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
How does infarction in victims of stroke and other types of acute brain injury expand to its definitive size in subsequent days? Spontaneous depolarizations that repeatedly spread across the cerebral cortex, sometimes at remarkably regular intervals, occur in patients with all types of injury. Here, we show experimentally with in vivo real-time imaging that similar, spontaneous depolarizations cycle repeatedly around ischaemic lesions in the cerebral cortex, and enlarge the lesion in step with each cycle. This behaviour results in regular periodicity of depolarization when monitored at a single point in the lesion periphery. We present evidence from clinical monitoring to suggest that depolarizations may cycle in the ischaemic human brain, perhaps explaining progressive growth of infarction. Despite their apparent detrimental role in infarct growth, we argue that cycling of depolarizations around lesions might also initiate upregulation of the neurobiological responses involved in repair and remodelling.
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Affiliation(s)
- Hajime Nakamura
- Max Planck Institute for Neurological Research, Gleueler Str. 50, 50931 Cologne, Germany
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153
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Kumaria A, Tolias CM. Normobaric hyperoxia therapy for traumatic brain injury and stroke: a review. Br J Neurosurg 2010; 23:576-84. [PMID: 19922270 DOI: 10.3109/02688690903050352] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Traumatic brain injury (TBI) and acute ischaemic stroke are major causes of mortality and morbidity and there is an urgent demand for new neuroprotective strategies following the translational failure of neuroprotective drug trials. Oxygen therapy--especially normobaric, may offer a simple and effective therapeutic strategy which we review in this paper. Firstly we review mechanisms underlying the therapeutic effects of hyperoxia (both normobaric and hyperbaric) including mitochondrial rescue, stabilisation of intracranial pressure, attenuation of cortical spreading depression and inducing favourable endothelial-leukocyte interactions, all effects of which are postulated to decrease secondary injury. Next we survey studies using hyperbaric oxygen therapy for TBI and stroke, which formed the basis for early studies on normobaric hyperoxia. Thirdly, we present clinical studies of the efficacy of normobaric hyperoxia on TBI and stroke, emphasising their safety, efficacy and practicality. Finally we consider safety concerns and side effects, particularly pulmonary pathology, respiratory failure and theoretical risks in paediatric patients. A neuroprotective role of normobaric hyperoxia is extremely promising and further studies are warranted.
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Affiliation(s)
- Ashwin Kumaria
- Department of Neurosurgery, King's College Hospital, London, UK.
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154
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Helbok R, Schmidt JM, Kurtz P, Hanafy KA, Fernandez L, Stuart RM, Presciutti M, Ostapkovich ND, Connolly ES, Lee K, Badjatia N, Mayer SA, Claassen J. Systemic Glucose and Brain Energy Metabolism after Subarachnoid Hemorrhage. Neurocrit Care 2010; 12:317-23. [DOI: 10.1007/s12028-009-9327-4] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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155
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Abstract
PURPOSE OF REVIEW Prognostic models for predicting outcome after severe traumatic brain injury (TBI) may be useful in several areas. However, established risk prediction models for general critical illness show significant limitations in neurotrauma. Development of specific risk prediction models for TBI has been difficult due to the variability of injury, which predicates a large sample for construction of robust models. Previous development of prognostic models for TBI has suffered from small sample sizes, poor study design and follow up, difficulty in application to clinical practice, limited inclusion of patients from low income countries, and lack of external validation. RECENT FINDINGS This situation has changed substantially in the last year with the development and validation of two new risk prediction models based on large datasets.The Corticosteroid Randomization after Significant Head Injury (CRASH) trial and the International Mission on Prognosis and Analysis of Clinical Trials in TBI (IMPACT) databases have been used to create prediction with or without computed tomography data, and been cross validated. In addition, the CRASH database was used to develop models for low/middle income countries. SUMMARY The outcome prediction models that have evolved from these databases are undergoing further refinement and validation, and it is likely that these advances will prove valuable in training clinicians, counselling patients' families, auditing unit performance, designing better clinical trials, and rational allocation of resources.
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156
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Tuseth V, Nordrehaug JE. Role of percutaneous left ventricular assist devices in preventing cerebral ischemia. Interv Cardiol 2009. [DOI: 10.2217/ica.09.27] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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157
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Abstract
Hyperglycemia is commonplace in the critically ill patient and is associated with worse outcomes. It occurs after severe stress (e.g., infection or injury) and results from a combination of increased secretion of catabolic hormones, increased hepatic gluconeogenesis, and resistance to the peripheral and hepatic actions of insulin. The use of carbohydrate-based feeds, glucose containing solutions, and drugs such as epinephrine may exacerbate the hyperglycemia. Mechanisms by which hyperglycemia cause harm are uncertain. Deranged osmolality and blood flow, intracellular acidosis, and enhanced superoxide production have all been implicated. The net result is derangement of endothelial, immune and coagulation function and an association with neuropathy and myopathy. These changes can be prevented, at least in part, by the use of insulin to maintain normoglycemia.
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Affiliation(s)
- David Brealey
- Bloomsbury Institute of Intensive Care Medicine, University College London, London, United Kingdom
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158
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Abstract
PURPOSE OF REVIEW This review highlights recent advances in cerebral microdialysis for investigational and clinical neurochemical monitoring in patients with critical neurological conditions. RECENT FINDINGS Use of microdialysis with other methods, including PET, electrophysiological monitoring and brain tissue oximetry in traumatic brain injury, subarachnoid hemorrhage with vasospasm, and infarction with refractory increased intracranial pressure have been reported. Potentially adverse neurochemical effects of nonconvulsive status epilepticus and cortical slow depolarization waves, both of which are increasingly recognized in traumatic brain injury and stroke patients, have been reported. The explosive growth in the use of cerebral oximetry with targeted management of brain tissue oxygen levels is leading to greater understanding of derangements of cerebral bioenergetics in the critically ill brain, but there remain unresolved basic issues. Understanding of the analytes that are measurable at the bedside - glucose, lactate, pyruvate, glutamate and glycerol - continues to evolve with glucose, lactate, pyruvate and the lactate-pyruvate ratio taking center stage. Analytes including inflammatory biomarkers such as cytokines and metabolites of nitric oxide are presently investigational, but hold promise for future application in advancing our understanding of basic pathophysiology, therapeutic target selection and prognostication. Growing consensus on indications for use of clinical microdialysis and advances in commercially available equipment continue to make microdialysis increasingly 'ready for prime time.' SUMMARY Cerebral microdialysis is an established tool for neurochemical research in the ICU. This technique cannot be fruitfully used in isolation, but when combined with other monitoring methods provides unique insights into the biochemical and physiological derangements in the injured brain.
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159
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Portnow J, Badie B, Chen M, Liu A, Blanchard S, Synold TW. The neuropharmacokinetics of temozolomide in patients with resectable brain tumors: potential implications for the current approach to chemoradiation. Clin Cancer Res 2009; 15:7092-8. [PMID: 19861433 DOI: 10.1158/1078-0432.ccr-09-1349] [Citation(s) in RCA: 175] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Intracerebral microdialysis (ICMD) is an accepted method for monitoring changes in neurochemistry from acute brain injury. The goal of this pilot study was to determine the feasibility of using ICMD to examine the neuropharmacokinetics of temozolomide in brain interstitium following oral administration. EXPERIMENTAL DESIGN Patients with primary or metastatic brain tumors had a microdialysis catheter placed in peritumoral brain tissue at the time of surgical debulking. Computerized tomography scan confirmed the catheter location. Patients received a single oral dose of temozolomide (150 mg/m2) on the first postoperative day, serial plasma and ICMD samples were collected over 24 hours, and temozolomide concentrations were determined by tandem mass spectrometry. RESULTS Nine patients were enrolled. Dialysate and plasma samples were successfully collected from seven of the nine patients. The mean temozolomide areas under the concentration-time curve (AUC) in plasma and brain interstitium were 17.1 and 2.7 microg/mL x hour, with an average brain interstitium/plasma AUC ratio of 17.8%. The mean peak temozolomide concentration in the brain was 0.6 +/- 0.3 microg/mL, and the mean time to reach peak level in brain was 2.0 +/- 0.8 hours. CONCLUSIONS The use of ICMD to measure the neuropharmacokinetics of systemically administered chemotherapy is safe and feasible. Concentrations of temozolomide in brain interstitium obtained by ICMD are consistent with published data obtained in a preclinical ICMD model, as well as from clinical studies of cerebrospinal fluid. However, the delayed time required to achieve maximum temozolomide concentrations in brain suggests that current chemoradiation regimens may be improved by administering temozolomide 2 to 3 hours before radiation.
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Affiliation(s)
- Jana Portnow
- Department of Medical Oncology and Experimental Therapeutics, 1500 East Duarte Road, Duarte, CA 91010, USA.
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160
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Metzger JC, Eastman AL, Pepe PE. Year in review 2008: Critical Care--trauma. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2009; 13:226. [PMID: 19863766 PMCID: PMC2784337 DOI: 10.1186/cc7960] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Eleven papers on trauma published in Critical Care during 2008 addressed traumatic brain injury (TBI), burns, diagnostic concerns and immunosuppression. In regard to TBI, preliminary results indicate the utility of either magnetic resonance imaging (MRI) or ultrasound in measuring optic nerve sheath diameter to identify elevated intracranial pressure (ICP) as well as the potential benefit of thiopental for refractory ICP. Another investigaticc7960on demonstrated that early extubation of TBI patients whose Glasgow Coma Scale score was 8 or less did not result in additional incidence of nosocomial pneumonia. Another study indicated that strict glucose control resulted in worse outcomes during the first week after TBI, but improved outcomes after the second week. Another paper showed the prolonged neuroprotective advantages of proges-terone administration in TBI patients. There was also guidance on improved classifications of renal complications in burn patients. Another study found that patients with inhalation injuries and increased interleukin-6 (IL-6) and IL-10 and decreased IL-7 had increased mortality rates. One literature review described the disadvantages of prolonged immobilization or additional use of MRI for ruling out cervical spine injuries in obtunded TBI patients already cleared by computerized tomography scans. Other investigators found that higher N-terminal pro B-type natriuretic peptide (NT-proBNP) levels may be useful markers for post-traumatic cardiac impairment. Finally, an experimental model showed that both splenic apoptosis and lymphocytopenia may occur shortly after severe hemorrhage, thus increasing the threat of immunosuppression in those with severe blood loss.
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Affiliation(s)
- Jeffery C Metzger
- Department of Surgery, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Mail Code 8579, Dallas, TX 75390-8579, USA.
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161
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Li C, Ahn CH, Shutter LA, Narayan RK. Toward real-time continuous brain glucose and oxygen monitoring with a smart catheter. Biosens Bioelectron 2009; 25:173-8. [PMID: 19625179 DOI: 10.1016/j.bios.2009.06.032] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2009] [Revised: 06/21/2009] [Accepted: 06/22/2009] [Indexed: 10/20/2022]
Abstract
Oxygen and glucose biosensors have been designed, fabricated, characterized and optimized for real-time continuous monitoring on a new smart catheter for use in patients with traumatic brain injury (TBI). Oxygen sensors with three-electrode configuration were designed to achieve zero net oxygen consumption. Glucose sensors were based on the use of platinum nanoparticle-enhanced electrodes that were modified with polycation and glucose oxidase immobilized by chitosan matrix. An iridium oxide electrode was developed to work as a biocompatible reference electrode with enhanced durability and stability in the biological solutions. A study of the effect of temperature on oxygen sensor performance, and both temperature and oxygen effects on glucose sensor performance were accomplished to enhance their operative stability and provide useful information for in vivo applications. A new methodology for automatic correction of the temperature and oxygen dependence of biosensor outputs is demonstrated through programmed LabView software. In vitro experiments in both physiological and pathophysiological ranges (oxygen: 0-60 mmHg; glucose: 0.1-10 mM; temperature: 25-40 degrees C) with clinical samples of cerebrospinal fluid obtained from TBI patients have demonstrated stable measurements with enhanced accuracy, indicating the feasibility of the sensors for a real-time continuous in vivo monitoring.
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Affiliation(s)
- Chunyan Li
- Department of Neurosurgery, University of Cincinnati, Cincinnati, OH 45267, USA.
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162
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Clinical impact of early hyperglycemia during acute phase of traumatic brain injury. Neurocrit Care 2009; 11:151-7. [PMID: 19479209 DOI: 10.1007/s12028-009-9228-6] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Accepted: 04/24/2009] [Indexed: 12/21/2022]
Abstract
INTRODUCTION While tight glucose control has been widely adopted in the critical care setting, the optimal target glucose level following acute traumatic brain injury (TBI) remains debatable. This observational study was conducted to delineate the relationship between glucose levels and clinical outcomes during acute phase (first 5 days) of TBI. METHODS We retrospectively identified 429 TBI patients admitted to the intensive care unit (ICU) from January 2005 to December 2006. Of those, 380 patients were retained for final analysis. Collected data included demographics, admission Glasgow Coma Scale (GCS), and APACHE II, glucose on admission and during the first 5 days of admission, and insulin use. Clinical outcomes included mortality, ICU, and hospital length of stay. RESULTS The overall hospital mortality was 13.2% (n = 50). Demographics were similar between survivor and nonsurvivor groups; however, nonsurvivors were older and had worse disease severity on admission. Nonsurvivors also had significantly higher glucose levels at admission and during the first 24 h of admission (P < 0.001). Based on the receiver operating characteristic (ROC) curve, admission and day-1 peak glucose were better predictors for mortality compared to hospital days 2-5 glucose levels, with day-1 peak glucose being the best predictor of mortality (AUC = 0.820). A Kaplan-Meier survival analysis also showed that patients with glucose <160 mg/dl during the first day of ICU admission had a significantly better survival rate compared to those with glucose > or =160 mg/dl (P < 0.001). Two glucose bands, <60 and > or =160 mg/dl, were identified to be associated with increased mortality irrespective of injury severity (OR = 1.130; 95% CI 1.034-1.235; P = 0.007; OR = 1.034; 95% CI 1.021-1.047, P < 0.001; respectively). CONCLUSIONS Findings from our study suggest a glucose level > or =160 mg/dl within the first 24 h of admission following TBI is associated with poor outcomes irrespective of severity of injury, and this presents a timeframe for which active therapeutic interventions may improve clinical outcomes. Prospective efficacy trials are needed to corroborate these findings.
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163
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Schlenk F, Vajkoczy P, Sarrafzadeh A. Inpatient Hyperglycemia Following Aneurysmal Subarachnoid Hemorrhage: Relation to Cerebral Metabolism and Outcome. Neurocrit Care 2009; 11:56-63. [DOI: 10.1007/s12028-009-9222-z] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2009] [Accepted: 04/15/2009] [Indexed: 10/20/2022]
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164
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Zahed C, Gupta AK. Optimizing cerebral glucose in severe traumatic brain injury: still some way to go. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2009; 13:131. [PMID: 19435477 PMCID: PMC2689477 DOI: 10.1186/cc7753] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
This commentary considers some of the factors that affect cerebral glucose metabolism in patients with traumatic brain injury. A study recently reported in Critical Care suggested a blood glucose range that may optimize cerebral glucose utilization; the findings of this study are evaluated and discussed. Some of the mechanisms of cerebral glucose control are explored, including the impact of intensive insulin therapy on cerebral metabolism.
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Affiliation(s)
- Cameron Zahed
- Addenbrooke's Hospital, Cambridge University Hospitals NHS Foundation Trust, Hills Road, Cambridge CB2 2QQ, UK
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165
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Latorre JGS, Chou SHY, Nogueira RG, Singhal AB, Carter BS, Ogilvy CS, Rordorf GA. Effective glycemic control with aggressive hyperglycemia management is associated with improved outcome in aneurysmal subarachnoid hemorrhage. Stroke 2009; 40:1644-52. [PMID: 19286596 DOI: 10.1161/strokeaha.108.535534] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
BACKGROUND AND PURPOSE Hyperglycemia strongly predicts poor outcome in patients with aneurysmal subarachnoid hemorrhage, but the effect of hyperglycemia management on outcome is unclear. We studied the impact of glycemic control on outcome of patients with aneurysmal subarachnoid hemorrhage. METHODS A prospective intensive care unit database was used to identify 332 patients with hyperglycemic aneurysmal subarachnoid hemorrhage admitted between January 2000 and December 2006. Patients treated with an aggressive hyperglycemia management (AHM) protocol after 2003 (N=166) were compared with 166 patients treated using a standard hyperglycemia management before 2003. Within the AHM group, outcome was compared between patients who achieved good (mean glucose burden <1.1 mmol/L) and poor (mean glucose burden >or=1.1 mmol/L) glycemic control. Poor outcome was defined as modified Rankin scale >or=4 at 3 to 6 months. Multivariable logistic regression models correcting for temporal trend were used to quantify the effect of AHM on poor outcome. RESULTS Poor outcome in AHM-treated patients was lower (28.31% versus 40.36%) but was not statistically significant after correcting for temporal trend. However, good glycemic control significantly reduced the incidence of poor outcome (OR, 0.25; 95% CI, 0.08 to 0.80; P=0.02) compared with patients with poor glycemic control within the AHM group. No difference in the rate of clinical vasospasm or the development of delayed ischemic neurological deficit was seen before and after AHM protocol implementation. CONCLUSIONS AHM results in good glucose control and significantly reduces the odds for poor outcome after aneurysmal subarachnoid hemorrhage in glucose-controlled patients. Further studies are needed to confirm these results.
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166
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167
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Abstract
Intensive research investigating the relation between the management of glycemia and outcome in patients receiving neurocritical care has underlined the possible benefits and adverse events related to glucose control. Here, we review experimental and clinical studies investigating the effects of hypoglycemia and hyperglycemia on the brain that advance current knowledge on managing glycemia in patients receiving neurocritical care.
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168
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Komotar RJ, Schmidt JM, Starke RM, Claassen J, Wartenberg KE, Lee K, Badjatia N, Connolly ES, Mayer SA. RESUSCITATION AND CRITICAL CARE OF POOR-GRADE SUBARACHNOID HEMORRHAGE. Neurosurgery 2009; 64:397-410; discussion 410-1. [DOI: 10.1227/01.neu.0000338946.42939.c7] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Abstract
AS OUTCOMES HAVE improved for patients with aneurysmal subarachnoid hemorrhage, most mortality and morbidity that occur today are the result of severe diffuse brain injury in poor-grade patients. The premise of this review is that aggressive emergency cardiopulmonary and neurological resuscitation, coupled with early aneurysm repair and advanced multimodality monitoring in a specialized neurocritical care unit, offers the best approach for achieving further improvements in subarachnoid hemorrhage outcomes. Emergency care should focus on control of elevated intracranial pressure, optimization of cerebral perfusion and oxygenation, and medical and surgical therapy to prevent rebleeding. In the postoperative period, advanced monitoring techniques such as continuous electroencephalography, brain tissue oxygen monitoring, and microdialysis can detect harmful secondary insults, and may eventually be used as end points for goal-directed therapy, with the aim of creating an optimal physiological environment for the comatose injured brain. As part of this paradigm shift, it is essential that aggressive surgical and medical support be linked to compassionate end-of-life care. As neurosurgeons become confident that comfort care can be implemented in a straightforward fashion after a failed trial of early maximal intervention, the usual justification for withholding treatment (survival with neurological devastation) becomes less relevant, and lives may be saved as more patients recover beyond expectations.
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Affiliation(s)
- Ricardo J. Komotar
- Department of Neurological Surgery, Columbia University, New York, New York (Komotar)
| | - J. Michael Schmidt
- Neurological Intensive Care Unit, Department of Neurology, Columbia University, New York, New York
| | - Robert M. Starke
- Department of Neurological Surgery, Columbia University, New York, New York (Komotar)
| | - Jan Claassen
- Department of Neurological Surgery, Columbia University, New York, New York (Komotar)
- Neurological Intensive Care Unit, Department of Neurology, Columbia University, New York, New York
| | | | - Kiwon Lee
- Department of Neurological Surgery, Columbia University, New York, New York (Komotar)
- Neurological Intensive Care Unit, Department of Neurology, Columbia University, New York, New York
| | - Neeraj Badjatia
- Neurological Intensive Care Unit, Department of Neurology, Columbia University, New York, New York
| | - E. Sander Connolly
- Neurological Intensive Care Unit, Department of Neurological Surgery, Columbia University, New York, New York
| | - Stephan A. Mayer
- Department of Neurological Surgery, Columbia University, New York, New York (Komotar)
- Neurological Intensive Care Unit, Department of Neurology, Columbia University, New York, New York
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169
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Multimodality Monitoring in Patients with Elevated Intracranial Pressure. Intensive Care Med 2009. [DOI: 10.1007/978-0-387-77383-4_75] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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170
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Wilson JRF, Green A. Acute Traumatic Brain Injury: A Review of Recent Advances in Imaging and Management. Eur J Trauma Emerg Surg 2009; 35:176. [PMID: 26814773 DOI: 10.1007/s00068-008-8095-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2008] [Accepted: 12/06/2008] [Indexed: 10/21/2022]
Abstract
Acute traumatic brain injury (TBI) is a major cause of death and disability in young persons worldwide, producing a substantial economic burden on health services. New technology in computed tomography and magnetic resonance imaging is allowing the acquisition of more accurate and detailed information on cerebral pathology post-TBI. This has greatly improved prognostic ability in TBI and enables earlier identification of pathology, making it potentially amenable to therapeutic intervention. Recent advances in the management of TBI have been hampered by a lack of class I evidence arising from difficulties in applying strict study protocols to a patient subset as heterogeneous as post-TBI patients. The most definite benefits in terms of survival after TBI come from admission to a specialist neurosurgical centre, with goal-targeted therapy and intensive care services. Some traditional therapies for the treatment of acute TBI have been proven to be harmful and should be avoided. A number of management strategies have proved potentially beneficial post-TBI, but there is insufficient evidence to make definitive recommendations at present. Future therapies that are currently under investigation include decompressive craniectomy, progesterone therapy, and possibly therapeutic hypothermia.
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Affiliation(s)
- Jamie R F Wilson
- University of Oxford Medical Sciences Division, John Radcliffe Hospital, Headley Way, Headington, Oxford, UK. .,University of Oxford Medical Sciences Division, John Radcliffe Hospital, Headley Way, Headington, Oxford, OX39DU, UK.
| | - Alex Green
- Department of Neurosurgery, West Wing, John Radcliffe Hospital, Oxford, UK
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171
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Shooman D, Portess H, Sparrow O. A review of the current treatment methods for posthaemorrhagic hydrocephalus of infants. Cerebrospinal Fluid Res 2009; 6:1. [PMID: 19183463 PMCID: PMC2642759 DOI: 10.1186/1743-8454-6-1] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2008] [Accepted: 01/30/2009] [Indexed: 11/10/2022] Open
Abstract
Posthaemorrhagic hydrocephalus (PHH) is a major problem for premature infants, generally requiring lifelong care. It results from small blood clots inducing scarring within CSF channels impeding CSF circulation. Transforming growth factor – beta is released into CSF and cytokines stimulate deposition of extracellular matrix proteins which potentially obstruct CSF pathways. Prolonged raised pressures and free radical damage incur poor neurodevelopmental outcomes. The most common treatment involves permanent ventricular shunting with all its risks and consequences. This is a review of the current evidence for the treatment and prevention of PHH and shunt dependency. The Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library) and PubMed (from 1966 to August 2008) were searched. Trials using random or quasi-random patient allocation for any intervention were considered in infants less than 12 months old with PHH. Thirteen trials were identified although speculative interventions were also evaluated. The literature confirms that lumbar punctures, diuretic drugs and intraventricular fibrinolytic therapy can have significant adverse effects and fail to prevent shunt dependence, death or disability. There is no evidence that postnatal phenobarbital administration prevents intraventricular haemorrhage (IVH). Subcutaneous reservoirs and external drains have not been tested in randomized controlled trials, but can be useful as a temporising measure. Drainage, irrigation and fibrinolytic therapy as a way of removing blood to inhibit progressive deposition of matrix proteins, permanent hydrocephalus and shunt dependency, are invasive and experimental. Studies of ventriculo-subgaleal shunts show potential as a temporary method of CSF diversion, but have high infection rates. At present no clinical intervention has been shown to reduce shunt surgery in these infants. A ventricular shunt is not advisable in the early phase after PHH. Evidence exists that pre-delivery corticosteroid therapy reduces mortality and IVH and there may be trends towards reduced disability in the short term. There is also evidence that postnatal indomethacin reduces IVH but with no effect on mortality or disability. Overall, there is still no definitive algorithm for the treatment of PHH or prevention of shunt dependence. New therapeutic approaches in neonatal care, including those aimed at pre-empting PHH, offer the best hope of improving neurodevelopmental outcomes.
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Affiliation(s)
- David Shooman
- Department of Neurosurgery, Wessex Neurological Centre, Southampton General Hospital, Tremona Road, Southampton, Hampshire, SO16 6YD, UK.
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172
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Schlenk F, Frieler K, Nagel A, Vajkoczy P, Sarrafzadeh AS. Cerebral microdialysis for detection of bacterial meningitis in aneurysmal subarachnoid hemorrhage patients: a cohort study. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2009; 13:R2. [PMID: 19154580 PMCID: PMC2688112 DOI: 10.1186/cc7689] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2008] [Revised: 11/10/2008] [Accepted: 01/20/2009] [Indexed: 12/02/2022]
Abstract
Introduction Bacterial meningitis (BM) is a severe complication in patients with aneurysmal subarachnoid haemorrhage (SAH). Clinical signs of meningitis are often masked by SAH-related symptoms, and routine cerebrospinal fluid (CSF) analysis fails to indicate BM. Microdialysis (MD) is a technique for monitoring cerebral metabolism in patients with SAH. A cohort study was performed to investigate the value of MD for the diagnosis of BM. Methods Retrospectively, 167 patients with SAH in an ongoing investigation on cerebral metabolism monitored by MD were analysed for the presence of BM and related MD changes. Diagnosis of BM was based on microbiological CSF culture or clinical symptoms responding to antibiotic treatment, combined with an increased CSF cell count and/or fever. Levels of MD parameters before and after diagnosis of BM were analysed and compared with the spontaneous course in controls. Results BM developed in 20 patients, of which 12 underwent MD monitoring at the time of diagnosis. A control group was formed using 147 patients with SAH not developing meningitis. On the day BM was diagnosed, cerebral glucose was lower compared with the value three days before (p = 0.012), and the extent of decrease was significantly higher than in controls (p = 0.044). A decrease in cerebral glucose by 1 mmol/L combined with the presence of fever ≥ 38°C indicated BM with a sensitivity of 69% and a specificity of 80%. CSF chemistry failed to indicate BM, but the cell count increased during the days before diagnosis (p < 0.05). Conclusions A decrease in MD glucose combined with the presence of fever detected BM with acceptable sensitivity and specificity, while CSF chemistry failed to indicate BM. In patients with SAH where CSF cell count is not available or helpful, MD might serve as an adjunct criterion for early diagnosis of BM.
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Affiliation(s)
- Florian Schlenk
- Department of Neurosurgery, Charité - Universitätsmedizin Berlin, Campus Virchow Klinikum, Berlin, Germany.
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173
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Schlenk F, Sarrafzadeh AS. Is continuous insulin treatment safe in aneurysmal subarachnoid hemorrhage? Vasc Health Risk Manag 2009; 4:885-91. [PMID: 19066006 PMCID: PMC2597760 DOI: 10.2147/vhrm.s1924] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Objectives: To investigate the long-term effect of continuous insulin infusion for glucose control on cerebral metabolism in aneurysmal subarachnoid hemorrhage (SAH) patients. Methods: Prospective, nonrandomized study of 31 SAH patients in the ICU (52 ± 10 years, WFNS Grade 2.9 ± 1.6). A microdialysis catheter was inserted into the vascular territory of the aneurysm. Metabolic changes during 4 days after onset of insulin infusion were analyzed. Blood glucose levels >140 mg/dL after clinical stabilization were treated with intravenous insulin. Results: 24 patients were treated with intravenous insulin. Though no insulin-induced hypoglycemia occurred, cerebral glucose decreased on days 1–4 after insulin onset without reaching critical levels. Glycerol, a marker of membrane degradation, showed a reversible increase on day 1 while the lactate/pyruvate ratio remained stable and glutamate even decreased indicating absence of severe cerebral crisis following insulin infusion and excluding ischemia as a cause for cerebral glucose depletion. Conclusions: Concerning cerebral metabolism, long-term continuous insulin infusion appears to be safe as long as cerebral glucose levels do not fall below the physiological range. In view of the high incidence of hyperglycemia and need for insulin treatment, future studies on the effect of insulin on cerebral metabolism in SAH patients are desirable.
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Affiliation(s)
- Florian Schlenk
- Clinic of Neurosurgery, Charité Campus Virchow Medical Center, Berlin, Germany
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174
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Hashemi P, Bhatia R, Nakamura H, Dreier JP, Graf R, Strong AJ, Boutelle MG. Persisting depletion of brain glucose following cortical spreading depression, despite apparent hyperaemia: evidence for risk of an adverse effect of Leão's spreading depression. J Cereb Blood Flow Metab 2009; 29:166-75. [PMID: 18813306 DOI: 10.1038/jcbfm.2008.108] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Rapid sampling microdialysis (rsMD) directed towards the cerebral cortex has allowed identification of a combined time-series signature for glucose and lactate that characterizes peri-infarct depolarization in experimental focal ischaemia, but no comparable data exist for 'classical' cortical spreading depression (CSD) associated with hyperaemia in the normally perfused brain. Here, we examined the rsMD responses of dialysate glucose and lactate to five hyperaemic spreading depressions induced with intracortical microinjections, typically of 1 mol/L KCl, in open-skull preparations in five cats under chloralose anaesthesia. Depolarization was verified with microelectrodes, and laser speckle flowmetry was used to examine propagation of the events and perfusion responses near the MD probe. Ten minutes after depolarization, dialysate glucose fell and lactate rose by 28% and 58% respectively. There was no recovery of dialysate glucose 30 mins after depolarization. Mean baseline indicative cerebral blood flow was 25.5+/-4.1 mL/100 g/min and mean maximum hyperaemic increase was by 29.6+/-6 mL/100 g/min; hyperaemia remained present 30 mins after CSD. As CSD events are repetitive, frequent, and often clustered temporally in human acute brain injury, these results indicate a high risk of depletion of extracellular glucose in association with depolarization events of a pattern previously thought to be largely benign.
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175
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Abstract
Transcranial perfusion monitoring provides early warning of impending brain ischemia and may be used to guide management of cerebral perfusion and oxygenation. The monitoring options include measurement of intracranial and cerebral perfusion pressures, assessment of cerebral blood flow, and assessment of the adequacy of perfusion by measurement of cerebral oxygenation and brain tissue biochemistry. Some monitoring techniques are well established, whereas others are relatively new to the clinical arena and their indications are still being evaluated. Currently available monitoring techniques are reviewed and their appropriateness and application to the perioperative period is discussed.
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Affiliation(s)
- Martin Smith
- Department of Neuroanaesthesia and Neurocritical Care, The National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Trust and Centre for Anaesthesia, London, UK.
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176
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Impact of tight glycemic control on cerebral glucose metabolism after severe brain injury: A microdialysis study*. Crit Care Med 2008; 36:3233-8. [DOI: 10.1097/ccm.0b013e31818f4026] [Citation(s) in RCA: 219] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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177
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Hartings JA, Gugliotta M, Gilman C, Strong AJ, Tortella FC, Bullock MR. Repetitive cortical spreading depolarizations in a case of severe brain trauma. Neurol Res 2008; 30:876-82. [PMID: 18534057 DOI: 10.1179/174313208x309739] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVE AND IMPORTANCE Cortical spreading depolarizations (CSD) are waves of mass tissue depolarization that mediate progressive development of cortical infarction in animal models and occur in approximately 50% of patients with acute brain injury. Here we performed multi-modal cerebral monitoring to investigate pathologies associated with CSD occurrence in a case of severe traumatic brain injury. CLINICAL PRESENTATION A 20 years old male suffering severe traumatic brain injury from a fall had extensive frontal subdural and intraparenchymal hemorrhage with mass effect. Craniectomy was performed for hematoma evacuation and decompression. INTERVENTION During surgery, a subdural electrocorticography (ECoG) electrode strip, along with microdialysis and PtiO2 probes, was placed beside injured cortex for CSD monitoring. Within 13-81 hours post-injury, 34 CSD occurred. CSD incidence increased during spontaneous hyperthermia and decreased during induced normothermia. Periods of CSD activity were also associated with low brain glucose (<0.10 mmol/l), elevated glutamate (>40 mmol/l) and lactate/pyruvate (>40), and PtiO2<10 mmHg. CSD caused progressive deterioration of ECoG activity only in regions with infarction at follow-up on day 27. CONCLUSION Repetitive mass tissue depolarizations accompanied a negative course of hemorrhagic lesion progression in the presence of ischemic conditions after traumatic brain injury. Whether as cause or effect, CSD may represent an inherent component of progressive metabolic failure leading to tissue death, and temperature appears to be an important factor influencing their occurrence. Continuous ECoG is a valuable tool for monitoring subclinical events such as CSD and seizures and for translational research in acute brain injury mechanisms and therapeutics.
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Affiliation(s)
- Jed A Hartings
- Division of Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA.
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178
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Brain metabolic and hemodynamic effects of cyclosporin A after human severe traumatic brain injury: a microdialysis study. Acta Neurochir (Wien) 2008; 150:1019-31; discussion 1031. [PMID: 18781275 DOI: 10.1007/s00701-008-0021-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Accepted: 07/18/2008] [Indexed: 12/21/2022]
Abstract
BACKGROUND Mitochondrial dysfunction is a major limiting factor in neuronal recovery following traumatic brain injury. Cyclosporin A (CsA) has been recently proposed for use in the early phase after severe head injury, for its ability to preserve mitochondrial bioenergetic state, potentially exerting a neuroprotective effect. The aim of this study was, therefore, to evaluate the effect of CsA on brain energy metabolism, as measured by cerebral microdialysis, and on cerebral hemodynamics, in a group of severely head injured patients. METHODS Fifty adult patients with a severe head injury were enrolled in this randomized, double-blind, placebo-controlled study. Patients received 5 mg/kg of CsA over 24 h, or placebo, within 12 h of the injury. A microdialysis probe was placed in all patients, who were managed according to standard protocols for the treatment of severe head injury. FINDINGS The most robust result of this study was that, over most of the monitoring period, brain dialysate glucose was significantly higher in the CsA treated patients than in placebo. Both lactate and pyruvate were also significantly higher in the CsA group. Glutamate concentration and lactate/pyruvate ratio were significantly higher in the placebo group than in CsA treated patients, respectively 1 to 2 days, and 2 to 3 days after the end of the 24-h drug infusion. The administration of CsA was also associated with a significant increase in mean arterial pressure (MAP) and cerebral perfusion pressure (CPP). CONCLUSIONS The administration of CsA in the early phase after head injury resulted in significantly higher extracellular fluid glucose and pyruvate, which may be evidence of a beneficial effect. The early administration of CsA was also associated with a significant increase in MAP and CPP and such a potentially beneficial hemodynamic effect might contribute to a neuroprotective effect.
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179
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Marcoux J, McArthur DA, Miller C, Glenn TC, Villablanca P, Martin NA, Hovda DA, Alger JR, Vespa PM. Persistent metabolic crisis as measured by elevated cerebral microdialysis lactate-pyruvate ratio predicts chronic frontal lobe brain atrophy after traumatic brain injury. Crit Care Med 2008; 36:2871-7. [PMID: 18766106 DOI: 10.1097/ccm.0b013e318186a4a0] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE To determine whether persistent metabolic dysfunction in normal-appearing frontal lobe tissue is correlated with long-term tissue atrophy. DESIGN Prospective monitoring with retrospective data analysis. SETTING Single-center academic neurointensive care unit. PATIENTS Fifteen patients with moderate to severe traumatic brain injury (Glasgow Coma Scale score 3-12). INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Hourly cerebral microdialysis was performed for the initial 96 hrs after trauma to determine extracellular levels of glucose, glutamate, glycerol, lactate, and pyruvate in normal appearing frontal lobes. Six months after injury, the anatomical outcome was assessed by measures of global and regional cerebral atrophy using volumetric brain magnetic resonance imaging. The lactate/pyruvate ratio was elevated >40 after traumatic brain injury in most patients, with a mean percent time of 32 +/- 29% of hours monitored. At 6 months after traumatic brain injury, there was a mean frontal lobe atrophy of 12 +/- 11% and global brain atrophy of 8.5 +/- 4.5%. The percentage of time of elevated lactate/pyruvate ratio correlated with the extent of frontal lobe brain atrophy (r = -.56, p < 0.01), but not global brain atrophy (r = -.31, p = 0.20). The predictive effect of lactate/pyruvate ratio was independent of patient age, Glasgow Coma Scale score, and volume of frontal lobe contusion. CONCLUSION Persistent metabolic crisis, as reflected by an elevated lactate/pyruvate ratio, in normal appearing posttraumatic frontal lobe, is predictive of the degree of tissue atrophy at 6 months.
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Affiliation(s)
- Judith Marcoux
- Department of Neurosurgery, Montreal Neurologic Institute, Montréal, QC, Canada
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180
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Hillary FG, Liu WC, Genova HM, Maniker AH, Kepler K, Greenwald BD, Cortese BM, Homnick A, Deluca J. Examining lactate in severe TBI using proton magnetic resonance spectroscopy. Brain Inj 2008; 21:981-91. [PMID: 17729050 DOI: 10.1080/02699050701426964] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
PRIMARY OBJECTIVE Clinical management of acute traumatic brain injury (TBI) has emphasized identification of secondary mechanisms of pathophysiology. An important objective in this study is to use proton magnetic resonance spectroscopy (pMRS) to examine early metabolic disturbance due to TBI. RESEARCH DESIGN The current design is a case study with repeated measures. METHOD AND PROCEDURE Proton magnetic resonance imaging was used to examine neurometabolism in this case of very severe brain trauma at 9 and 23 days post-injury. MRI was performed on a clinical 1.5 Tesla scanner. MAIN OUTCOMES AND RESULTS These data also reveal that pMRS methods can detect lactate elevations in an adult surviving severe head trauma and are sensitive to changes in basic neurometabolism during the first month of recovery. CONCLUSIONS The current case study demonstrates the sensitivity of pMRS in detecting metabolic alterations during the acute recovery period. The case study reveals that lactate elevations may be apparent for weeks after severe neurotrauma. Further work in this area should endeavour to determine the ideal time periods for pMRS examination in severe TBI as well as the ideal locations of data acquisition (e.g. adjacent or distal to lesion sites).
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Affiliation(s)
- F G Hillary
- Psychology Department, Pennsylvania State University, University Park, PA 16802, USA.
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181
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McAdoo DJ, Wu P. Microdialysis in central nervous system disorders and their treatment. Pharmacol Biochem Behav 2008; 90:282-96. [PMID: 18436292 DOI: 10.1016/j.pbb.2008.03.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2007] [Revised: 02/27/2008] [Accepted: 03/05/2008] [Indexed: 01/17/2023]
Abstract
Central nervous system (CNS) insults elevate endogenous toxins and alter levels of indicators of metabolic disorder. These contribute to neurotrauma, neurodegenerative diseases and chronic pain and are possible targets for pharmaceutical treatment. Microdialysis samples substances in the extracellular space for chemical analysis. It has demonstrated that toxic levels of glutamate are released and that toxic levels of the reactive species O(2)(-), H(2)O(2), HO. NO and HOONO are generated upon CNS injury. Agent administration by microdialysis can also help elucidate mechanisms of damage and protection, and to identify targets for clinical application. Microdialysis sampling indicates that circuits descending from the brain to the spinal cord transmit and modulate pain signals by releasing neurotransmitter amines and amino acids. Efforts are under way to develop microdialysis into a technique for intensive care monitoring and predicting outcomes of brain insults. Finally, microdialysis sampling has demonstrated in vivo elevation of glial cell line-derived neurotrophic factor following grafting of primed fetal human neural stem cells into brain-injured rats, the first in vivo demonstration of the release of a neurotrophic factor by grafted stem cells. This increased release correlated with significantly improved spatial learning and memory.
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Affiliation(s)
- David J McAdoo
- Department of Neurosciences and Cell Biology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-1043, United States.
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182
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Schlenk F, Nagel A, Graetz D, Sarrafzadeh AS. Hyperglycemia and cerebral glucose in aneurysmal subarachnoid hemorrhage. Intensive Care Med 2008; 34:1200-7. [DOI: 10.1007/s00134-008-1044-5] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2007] [Accepted: 01/25/2008] [Indexed: 01/04/2023]
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183
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Strong AJ. The management of plasma glucose in acute cerebral ischaemia and traumatic brain injury: more research needed. Intensive Care Med 2008; 34:1169-72. [PMID: 18320166 DOI: 10.1007/s00134-008-1045-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2008] [Accepted: 02/06/2008] [Indexed: 01/04/2023]
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184
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Abstract
PURPOSE OF REVIEW A substantial body of evidence supports the use of intensive insulin therapy in general critical care practice, particularly in surgical intensive care unit patients. The impact of intensive insulin therapy on the outcome of critically ill neurological patients, however, is still controversial. While avoidance of hyperglycemia is recommended in neurointensive care, no recommendations exist regarding the optimal target for systemic glucose control after severe brain injury. RECENT FINDINGS An increase in brain metabolic demand leading to a deficiency in cerebral extracellular glucose has been observed in critically ill neurological patients and correlates with poor outcome. In this setting, a reduction of systemic glucose below 6 mmol/l with exogenous insulin has been found to exacerbate brain metabolic distress. Recent studies have confirmed these findings while showing intensive insulin therapy to have no substantial benefit on the outcome of critically ill neurological patients. SUMMARY Questions persist regarding the optimal target for glucose control after severe brain injury. Further studies are needed to analyze the impact of intensive insulin therapy on brain glucose metabolism and outcome of critically ill neurological patients. According to the available evidence, a less restrictive target for systemic glucose control (6-10 mmol/l) may be more appropriate.
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Affiliation(s)
- Mauro Oddo
- Division of Neurocritical Care, Columbia University Medical Center, New York, USA.
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185
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Schlenk F, Graetz D, Nagel A, Schmidt M, Sarrafzadeh AS. Insulin-related decrease in cerebral glucose despite normoglycemia in aneurysmal subarachnoid hemorrhage. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2008; 12:R9. [PMID: 18218076 PMCID: PMC2374587 DOI: 10.1186/cc6776] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2007] [Revised: 12/01/2007] [Accepted: 01/24/2008] [Indexed: 01/04/2023]
Abstract
Introduction Hyperglycaemia following aneurysmal subarachnoid hemorrhage (SAH) is associated with complications and impaired neurological recovery. The aim of this study was to determine the effect of insulin treatment for glucose control on cerebral metabolism in SAH patients. Methods This prospective, nonrandomized study was conducted in 31 SAH patients in an intensive care unit (age 52 ± 10 years, World Federation of Neurological Surgeons grade 2.9 ± 1.6). A microdialysis catheter was inserted into the vascular territory of the aneurysm after clipping. Blood glucose levels above 140 mg/dl were treated with intravenous insulin and the microdialysates were analyzed hourly for the first 12 hours of infusion. Results No hypoglycaemia occurred. Twenty-four patients were treated with insulin for glucose control. Higher age and World Federation of Neurological Surgeons score were risk factors for need for insulin treatment (P < 0.05). Although blood glucose remained stable after initiation of insulin infusion, insulin induced a significant decrease in cerebral glucose at 3 hours after onset of the infusion until the end of the observation period (P < 0.05), reflecting high glucose utilization. The lactate:pyruvate ratio and glutamate did not increase, excluding ischaemia as possible cause of the decrease in glucose. Glycerol tended toward higher values at the end of the observation period (9 to 12 hours), reflecting either tissue damage after SAH or the beginning of cellular distress after insulin infusion. Conclusion Higher SAH grade was among the risk factors for need for insulin. Intensive glycaemic control using insulin induced a decrease of cerebral glucose and a slight increase in glycerol, though blood glucose remained normal. Future studies might detect relevant metabolic derangements when insulin treatment starts at low cerebral glucose levels, and may allow us to design a strategy for avoidance of insulin-induced metabolic crisis in SAH patients.
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Affiliation(s)
- Florian Schlenk
- Department of Neurosurgery, Charité Campus Virchow Medical Center, Augustenburger Platz, 13353 Berlin, Germany
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186
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Meier R, Béchir M, Ludwig S, Sommerfeld J, Keel M, Steiger P, Stocker R, Stover JF. Differential temporal profile of lowered blood glucose levels (3.5 to 6.5 mmol/l versus 5 to 8 mmol/l) in patients with severe traumatic brain injury. Crit Care 2008; 12:R98. [PMID: 18680584 PMCID: PMC2575586 DOI: 10.1186/cc6974] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2008] [Revised: 07/14/2008] [Accepted: 08/04/2008] [Indexed: 01/04/2023] Open
Abstract
INTRODUCTION Hyperglycaemia is detrimental, but maintaining low blood glucose levels within tight limits is controversial in patients with severe traumatic brain injury, because decreased blood glucose levels can induce and aggravate underlying brain injury. METHODS In 228 propensity matched patients (age, sex and injury severity) treated in our intensive care unit (ICU) from 2000 to 2004, we retrospectively evaluated the influence of different predefined blood glucose targets (3.5 to 6.5 versus 5 to 8 mmol/l) on frequency of hypoglycaemic and hyperglycaemic episodes, insulin and norepinephrine requirement, changes in intracranial pressure and cerebral perfusion pressure, mortality and length of stay on the ICU. RESULTS Mortality and length of ICU stay were similar in both blood glucose target groups. Blood glucose values below and above the predefined levels were significantly increased in the 3.5 to 6.5 mmol/l group, predominantly during the first week. Insulin and norepinephrine requirements were markedly increased in this group. During the second week, the incidences of intracranial pressure exceeding 20 mmHg and infectious complications were significantly decreased in the 3.5 to 6.5 mmol/l group. CONCLUSION Maintaining blood glucose within 5 to 8 mmol/l appears to yield greater benefit during the first week. During the second week, 3.5 to 6.5 mmol/l is associated with beneficial effects in terms of reduced intracranial hypertension and decreased rate of pneumonia, bacteraemia and urinary tract infections. It remains to be determined whether patients might profit from temporally adapted blood glucose limits, inducing lower values during the second week, and whether concomitant glucose infusion to prevent hypoglycaemia is safe in patients with post-traumatic oedema.
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Affiliation(s)
- Regula Meier
- Surgical Intensive Care Medicine, University Hospital Zuerich, Raemistrasse 100, CH 8091 Zuerich, Switzerland
| | - Markus Béchir
- Surgical Intensive Care Medicine, University Hospital Zuerich, Raemistrasse 100, CH 8091 Zuerich, Switzerland
| | - Silke Ludwig
- Surgical Intensive Care Medicine, University Hospital Zuerich, Raemistrasse 100, CH 8091 Zuerich, Switzerland
| | - Jutta Sommerfeld
- Surgical Intensive Care Medicine, University Hospital Zuerich, Raemistrasse 100, CH 8091 Zuerich, Switzerland
| | - Marius Keel
- Department of Surgery, Division of Trauma Surgery, University Hospital Zuerich, Raemistrasse 100, CH 8091 Zuerich, Switzerland
| | - Peter Steiger
- Surgical Intensive Care Medicine, University Hospital Zuerich, Raemistrasse 100, CH 8091 Zuerich, Switzerland
| | - Reto Stocker
- Surgical Intensive Care Medicine, University Hospital Zuerich, Raemistrasse 100, CH 8091 Zuerich, Switzerland
| | - John F Stover
- Surgical Intensive Care Medicine, University Hospital Zuerich, Raemistrasse 100, CH 8091 Zuerich, Switzerland
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187
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Nonconvulsive electrographic seizures after traumatic brain injury result in a delayed, prolonged increase in intracranial pressure and metabolic crisis. Crit Care Med 2007. [DOI: 10.1097/00003246-200712000-00023] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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188
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Nonconvulsive electrographic seizures after traumatic brain injury result in a delayed, prolonged increase in intracranial pressure and metabolic crisis. Crit Care Med 2007. [DOI: 10.1097/01.ccm.0000295667.66853.bc] [Citation(s) in RCA: 238] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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189
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Dusick JR, Glenn TC, Lee WNP, Vespa PM, Kelly DF, Lee SM, Hovda DA, Martin NA. Increased pentose phosphate pathway flux after clinical traumatic brain injury: a [1,2-13C2]glucose labeling study in humans. J Cereb Blood Flow Metab 2007; 27:1593-602. [PMID: 17293841 DOI: 10.1038/sj.jcbfm.9600458] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Patients with traumatic brain injury (TBI) routinely exhibit cerebral glucose uptake in excess of that expected by the low levels of oxygen consumption and lactate production. This brings into question the metabolic fate of glucose. Prior studies have shown increased flux through the pentose phosphate cycle (PPC) during cellular stress. This study assessed the PPC after TBI in humans. [1,2-(13)C(2)]glucose was infused for 60 mins in six consented, severe-TBI patients (GCS<9) and six control subjects. Arterial and jugular bulb blood sampled during infusion was analyzed for (13)C-labeled isotopomers of lactate by gas chromatography/mass spectroscopy. The product of lactate concentration and fractional abundance of isotopomers was used to determine blood concentration of each isotopomer. The difference of jugular and arterial concentrations determined cerebral contribution. The formula PPC=(m1/m2)/(3+(m1/m2)) was used to calculate PPC flux relative to glycolysis. There was enrichment of [1,2-(13)C(2)]glucose in arterial-venous blood (enrichment averaged 16.6% in TBI subjects and 28.2% in controls) and incorporation of (13)C-label into lactate, showing metabolism of labeled substrate. The PPC was increased in TBI patients relative to controls (19.6 versus 6.9%, respectively; P=0.002) and was excellent for distinguishing the groups (AUC=0.944, P<0.0001). No correlations were found between PPC and other clinical parameters, although PPC was highest in patients studied within 48 h of injury (averaging 33% versus 13% in others; P=0.0006). This elevation in the PPC in the acute period after severe TBI likely represents a shunting of substrate into alternative biochemical pathways that may be critical for preventing secondary injury and initiating recovery.
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Affiliation(s)
- Joshua R Dusick
- Division of Neurosurgery and Cerebral Blood Flow Laboratory, University of California at Los Angeles, Los Angeles, California 90095-7039, USA
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190
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Abstract
Transcranial perfusion monitoring provides early warning of impending brain ischemia and may be used to guide management of cerebral perfusion and oxygenation. The monitoring options include measurement of intracranial and cerebral perfusion pressures, assessment of cerebral blood flow, and assessment of the adequacy of perfusion by measurement of cerebral oxygenation and brain tissue biochemistry. Some monitoring techniques are well established, whereas others are relatively new to the clinical arena and their indications are still being evaluated. Currently available monitoring techniques are reviewed and their appropriateness and application to the perioperative period is discussed.
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Affiliation(s)
- Martin Smith
- Department of Neuroanaesthesia and Neurocritical Care, The National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Trust, University College London, London, WC1N 3BG, UK.
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191
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Pistollato F, Chen HL, Schwartz PH, Basso G, Panchision DM. Oxygen tension controls the expansion of human CNS precursors and the generation of astrocytes and oligodendrocytes. Mol Cell Neurosci 2007; 35:424-35. [PMID: 17498968 DOI: 10.1016/j.mcn.2007.04.003] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2006] [Revised: 03/30/2007] [Accepted: 04/06/2007] [Indexed: 01/16/2023] Open
Abstract
Human neural precursor proliferation and potency is limited by senescence and loss of oligodendrocyte potential. We found that in vitro expansion of human postnatal brain CD133(+) nestin(+) precursors is enhanced at 5% oxygen, while raising oxygen tension to 20% depletes precursors and promotes astrocyte differentiation even in the presence of mitogens. Higher cell densities yielded more astrocytes regardless of oxygen tension. This was reversed by noggin at 5%, but not 20%, oxygen due to a novel repressive effect of low oxygen on bone morphogenetic protein (BMP) signaling. When induced to differentiate by mitogen withdrawal, 5% oxygen-expanded precursors generated 17-fold more oligodendrocytes than cells expanded in 20% oxygen. When precursors were expanded at 5% oxygen and then differentiated at 20% oxygen, oligodendrocyte maturation was further enhanced 2.5-fold. These results indicate that dynamic control of oxygen tension regulates different steps in fate and maturation and may be crucial for treating neurodegenerative diseases.
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Affiliation(s)
- Francesca Pistollato
- Center for Neuroscience Research, Children's Research Institute, Children's National Medical Center, 5th Floor, Suite 5340, 111 Michigan Avenue, N.W., Washington, DC 20010, USA
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192
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Tisdall MM, Smith M. Multimodal monitoring in traumatic brain injury: current status and future directions. Br J Anaesth 2007; 99:61-7. [PMID: 17548431 DOI: 10.1093/bja/aem143] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Traumatic brain injury (TBI) remains a major cause of morbidity and mortality, particularly in young people. Despite encouraging animal studies, human trials assessing the use of pharmacological agents after TBI have all failed to show efficacy. Current management strategies are therefore directed towards providing an optimal physiological environment in order to minimize secondary insults and maximize the body's own regenerative processes. Modern neurocritical care management utilizes a host of monitoring techniques to identify or predict the occurrence of secondary insults and guide subsequent therapeutic interventions in an attempt to minimize the resulting secondary injury. Recent data suggest that the use of protocolized management strategies, informed by multimodality monitoring, can improve patient outcome after TBI. Developments in multimodality monitoring have allowed a movement away from rigid physiological target setting towards an individually tailored, patient-specific, approach. The wealth of monitoring information available provides a challenge in terms of data integration and accessibility and modern software applications may aid this process.
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Affiliation(s)
- M M Tisdall
- Department of Neuroanaesthesia and Neurocritical Care, Box 30, The National Hospital for Neurology and Neurosurgery, Centre for Anaesthesia, University College London, Queen Square, London WC1N 3BG, UK
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193
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Abstract
OBJECTIVES This critical literature review examines historical and current investigations on the efficacy and mechanisms of hyperbaric oxygen (HBO) treatment in traumatic brain injury (TBI). Potential safety risks and oxygen toxicity, as well as HBO's future potential, are also discussed. METHODS Directed literature review. RESULTS Historically, cerebral vasoconstriction and increased oxygen availability were seen as the primary mechanisms of HBO in TBI. HBO now appears to be improving cerebral aerobic metabolism at a cellular level, namely, by enhancing damaged mitochondrial recovery. HBO given at the ideal treatment paradigm, 1.5 ATA for 60 minutes, does not appear to produce oxygen toxicity and is relatively safe. DISCUSSION The use of HBO in TBI remains controversial. Growing evidence, however, shows that HBO may be a potential treatment for patients with severe brain injury. Further investigations, including a multicenter prospective randomized clinical trial, will be required to definitively define the role of HBO in severe TBI.
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Affiliation(s)
- Sarah B Rockswold
- Division of Neurosurgery, Department of Surgery, Hennepin County Medical Center, Department of Neurosurgery, University of Minnesota, 701 Park Avenue, Minneapolis, MN 55415, USA
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194
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Hutchinson PJ, Gimson A, Al-Rawi PG, O'Connell MT, Czosnyka M, Menon DK. Microdialysis in the management of hepatic encephalopathy. Neurocrit Care 2007; 5:202-5. [PMID: 17290089 DOI: 10.1385/ncc:5:3:202] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 01/06/2023]
Abstract
INTRODUCTION Fulminant hepatic encephalopathy has a high mortality. METHODS This case report describes the role of cerebral microdialysis as an adjunct to the management of a 49 - year-old woman with hepatic encephalopathy secondary to a paracetamol overdose. RESULTS The application of the microdialysis technique, by detecting a very low cerebral glucose concentration in the presence of a normal plasma glucose, assisted in clinical decision making. CONCLUSIONS Cerebral microdialysis, by enabling continuous on-line monitoring of substrate delivery and metabolism, may have a role in the management of patients with fulminant hepatic failure.
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Affiliation(s)
- P J Hutchinson
- Academic Department of Neurosurgery, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK.
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195
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Vespa PM, O'Phelan K, McArthur D, Miller C, Eliseo M, Hirt D, Glenn T, Hovda DA. Pericontusional brain tissue exhibits persistent elevation of lactate/pyruvate ratio independent of cerebral perfusion pressure. Crit Care Med 2007; 35:1153-60. [PMID: 17334254 DOI: 10.1097/01.ccm.0000259466.66310.4f] [Citation(s) in RCA: 136] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE To determine whether pericontusional tissue exhibits neurochemical responsiveness to changes in cerebral perfusion pressure as measured by microdialysis lactate/pyruvate ratio. DESIGN Prospective monitoring with retrospective data analysis. SETTING Single-center academic neurologic intensive care unit. PATIENTS Twenty-one patients with severe traumatic brain injury (Glasgow Coma Scale score 3-8). INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Cerebral microdialysis was performed for the initial 7 days after traumatic brain injury. Thirteen patients had microdialysis probes in normal tissue and eight had two probes, one of which was located in pericontusional tissue. Retrospective analysis was performed to determine if microdialysis levels in pericontusional tissue demonstrates higher levels of lactate/pyruvate ratio than normal tissue and if lactate/pyruvate ratio increased with reductions in cerebral perfusion pressure. Univariate analysis revealed higher values for glutamate and lactate/pyruvate ratio in pericontusional tissue compared with normal tissue. However, based on the mixed-effects model analysis, the percent time of elevated lactate/pyruvate ratio was significantly higher in pericontusional tissue (40 +/- 59% vs. 17 +/- 37%, p < .05), and the mean lactate/pyruvate ratio values showed only a trend relationship (62 +/- 134 vs. 34 +/- 78, p < .06). When examined by cerebral perfusion pressure threshold, cerebral perfusion pressure <60 mm Hg was not associated with higher lactate/pyruvate ratio values in normal or pericontusional tissue. In addition, no single cerebral perfusion pressure threshold was associated with a significant reduction in lactate/pyruvate ratio in either pericontusional or normal tissue (p < .08). CONCLUSIONS Sustained increases in lactate/pyruvate ratio occurred more frequently in pericontusional tissue compared with normal brain tissue. The lactate/pyruvate ratio was not related to cerebral perfusion pressure, nor was the percent time-burden of elevated lactate/pyruvate ratio related to any particular sustained cerebral perfusion pressure threshold. Lactate/pyruvate ratio values appear to be elevated despite cerebral perfusion pressure values customarily considered to be adequate.
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196
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Strong AJ, Hartings JA, Dreier JP. Cortical spreading depression: an adverse but treatable factor in intensive care? Curr Opin Crit Care 2007; 13:126-33. [PMID: 17327732 DOI: 10.1097/mcc.0b013e32807faffb] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW The aetiology and management of secondary deterioration in patients with acute traumatic or ischaemic brain injury remain serious challenges for clinicians and also for basic neuroscientists. The occurrence of spreading depolarization events and some of their features in the cerebral cortex in patients with traumatic brain injury and aneurysmal subarachnoid haemorrhage, as documented in recent papers, represent a novel pathophysiological mechanism in this setting. RECENT FINDINGS The history and definitions of two critically different patterns of depolarization are reviewed on the basis of their physiology and pathophysiology, particularly the responses of the cerebral microcirculation to depolarization as seen in the laboratory. It is now becoming possible to conduct similar assessments in the brain-injured patient. Currently the recorded incidence of depolarization events in patients undergoing craniotomy for traumatic contusions is in the region of 50-60%, rising to 72% following major subarachnoid haemorrhage. SUMMARY Realization of the therapeutic potential of the new findings will depend on clear knowledge of the impact of the different patterns of depolarization on outcome. Meantime, current results call for even stricter attention during clinical management of acute brain injury to secondary factors such as body temperature and plasma glucose.
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Affiliation(s)
- Anthony J Strong
- King's College London, Department of Clinical Neurosciences, London, UK.
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197
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Poca MA, Sahuquillo J, Vilalta A, Garnacho A. Lack of utility of arteriojugular venous differences of lactate as a reliable indicator of increased brain anaerobic metabolism in traumatic brain injury. J Neurosurg 2007; 106:530-7. [PMID: 17432701 DOI: 10.3171/jns.2007.106.4.530] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Object
Ischemic lesions are highly prevalent in patients with traumatic brain injuries (TBIs) and are the single most important cause of secondary brain damage. The prevention and early treatment of these lesions is the primary aim in the modern treatment of these patients. One of the most widely used monitoring techniques at the bedside is quantification of brain extracellular level of lactate by using arteriojugular venous differences of lactate (AVDL). The purpose of this study was to determine the sensitivity, specificity, and predictive value of AVDL as an indicator of increases in brain lactate production in patients with TBIs.
Methods
Arteriojugular venous differences of lactate were calculated every 6 hours using samples obtained though a catheter placed in the jugular bulb in 45 patients with diffuse head injuries (57.8%) or evacuated brain lesions (42.2%). Cerebral lactate concentration obtained with a 20-kD microdialysis catheter implanted in undamaged tissue was used as the de facto gold standard.
Six hundred seventy-three AVDL determinations and cerebral microdialysis samples were obtained simultaneously; 543 microdialysis samples (81%) showed lactate values greater than 2 mmol/L, but only 21 AVDL determinations (3.1%) showed an increase in brain lactate. No correlation was found between AVDL and cerebral lactate concentration (ρ = 0.014, p = 0.719). Arteriojugular venous differences of lactate had a sensitivity and specificity of 3.3 and 97.7%, respectively, with a false-negative rate of 96.7% and a false-positive rate of 2.3%.
Conclusions
Arteriojugular venous differences of lactate do not reliably reflect increased cerebral lactate production and consequently are not reliable in ruling out brain ischemia in patients with TBIs. The clinical use of this monitoring method in neurocritical care should be reconsidered.
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Affiliation(s)
- Maria A Poca
- Department of Neurosurgery, Vail d'Hebron University Hospital and Vall d'Hebron Research Institute, Autonomous University of Barcelona, Spain
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198
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Chiolero RL, Mechanick JI. Nutrition support and metabolic control: from evidence-based to systems biology. Curr Opin Clin Nutr Metab Care 2007; 10:175-7. [PMID: 17285005 DOI: 10.1097/mco.0b013e328028fdb6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- René L Chiolero
- Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.
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199
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Vespa PM. The implications of cerebral ischemia and metabolic dysfunction for treatment strategies in neurointensive care. Curr Opin Crit Care 2006; 12:119-23. [PMID: 16543786 DOI: 10.1097/01.ccx.0000216577.57180.bd] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW This review outlines recent observations made in a clinical setting that document the extent and degree of cerebral ischemia and metabolic dysfunction after acute brain injury. The intent is to guide clinicians in considering how best to monitor and treat brain metabolism in the intensive care unit. RECENT FINDINGS Recent findings have documented that following brain injury there is a heterogeneous distribution of disturbed metabolism with some areas of the brain rendered severely oligemic or ischemic while other areas are less affected. Areas that are not truly ischemic, however, still appear to be at risk of excitotoxic injury. Various methods of monitoring the brain are compared and discussed, including positron emission tomography, brain parenchymal oxygenation monitoring, brain microdialysis, and continuous electroencephalography; important caveats are also presented. These methods are complementary and provide information about oxygen utilization and other aspects of brain metabolism. Integration of these methods into a practical clinical protocol is discussed. SUMMARY The intensive care of acute brain injury has entered a new era in which monitoring of brain metabolism will permit targeted therapy and may possibly minimize iatrogenic adverse effects by making better use of our powerful therapies.
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Affiliation(s)
- Paul M Vespa
- David Geffen School of Medicine at UCLA, University of California, Los Angeles, 90095, USA.
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Darbin O, Carre E, Naritoku D, Risso JJ, Lonjon M, Patrylo PR. Glucose metabolites in the striatum of freely behaving rats following infusion of elevated potassium. Brain Res 2006; 1116:127-31. [PMID: 16979147 DOI: 10.1016/j.brainres.2006.06.095] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2006] [Revised: 06/29/2006] [Accepted: 06/30/2006] [Indexed: 11/27/2022]
Abstract
The outcome of patients with traumatic brain injury (TBI) can be predicted by the extracellular potassium concentration and the change in energy homeostasis. In this study, the authors investigated the effects of high potassium concentrations on extracellular levels of glucose, pyruvate and lactate in the rat striatum. Applying artificial cerebrospinal fluid (ACSF) enriched with 120 mM potassium by reverse microdialysis leads to an increase in lactate and reduction in glucose and pyruvate. Consequently, the lactate to pyruvate ratio was also increased. These data are discussed in the context of recent studies on lactate/pyruvate conversion and the potential mechanisms whereby high potassium could affect this equilibrium. We conclude that ischemic-like events are unlikely to explain these K(+)-induced changes.
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Affiliation(s)
- Olivier Darbin
- Department of Physiology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA.
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