Research Interests: Bioinformatics, Informatics, Evidence Based Medicine, Clinical Trials, Biomarkers, and 15 moreElectroencephalography, Critical Care, Electrocardiography, Humans, Bio Informatics, Consensus, Data Collection, Clinical Sciences, Brain metabolism, Clinical Guidelines, Biological markers, Brain Physiology, Blood gas analysis, Clinical Protocols, and Brain injuries
Neurocritical care depends, in part, on careful patient monitoring but as yet there are little data on what processes are the most important to monitor, how these should be monitored, and whether monitoring these processes is... more
Neurocritical care depends, in part, on careful patient monitoring but as yet there are little data on what processes are the most important to monitor, how these should be monitored, and whether monitoring these processes is cost-effective and impacts outcome. At the same time, bioinformatics is a rapidly emerging field in critical care but as yet there is little agreement or standardization on what information is important and how it should be displayed and analyzed. The Neurocritical Care Society in collaboration with the European Society of Intensive Care Medicine, the Society for Critical Care Medicine, and the Latin America Brain Injury Consortium organized an international, multidisciplinary consensus conference to begin to address these needs. International experts from neurosurgery, neurocritical care, neurology, critical care, neuroanesthesiology, nursing, pharmacy, and informatics were recruited on the basis of their research, publication record, and expertise. They under...
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OBJECTIVEDifferences in clinical outcomes between centers and countries may reflect variation in patient characteristics, diagnostic and therapeutic policies, or quality of care. The purpose of this study was to investigate the presence... more
OBJECTIVEDifferences in clinical outcomes between centers and countries may reflect variation in patient characteristics, diagnostic and therapeutic policies, or quality of care. The purpose of this study was to investigate the presence and magnitude of between-center and between-country differences in outcome after aneurysmal subarachnoid hemorrhage (aSAH).METHODSThe authors analyzed data from 5972 aSAH patients enrolled in randomized clinical trials of 3 different treatments from the Subarachnoid Hemorrhage International Trialists (SAHIT) repository, including data from 179 centers and 20 countries. They used random effects logistic regression adjusted for patient characteristics and timing of aneurysm treatment to estimate between-center and between-country differences in unfavorable outcome, defined as a Glasgow Outcome Scale score of 1–3 (severe disability, vegetative state, or death) or modified Rankin Scale score of 4–6 (moderately severe disability, severe disability, or dea...
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Microdialysis enables the chemistry of the extracellular interstitial space to be monitored. Use of this technique in patients with acute brain injury has increased our understanding of the pathophysiology of several acute neurological... more
Microdialysis enables the chemistry of the extracellular interstitial space to be monitored. Use of this technique in patients with acute brain injury has increased our understanding of the pathophysiology of several acute neurological disorders. In 2004, a consensus document on the clinical application of cerebral microdialysis was published. Since then, there have been significant advances in the clinical use of microdialysis in neurocritical care. The objective of this review is to report on the International Microdialysis Forum held in Cambridge, UK, in April 2014 and to produce a revised and updated consensus statement about its clinical use including technique, data interpretation, relationship with outcome, role in guiding therapy in neurocritical care and research applications.
Research Interests: Anesthesiology, Traumatic Brain Injury, Medicine, Humans, Outcome, and 9 moreCritical Care Medicine & Emergency Management, Subarachnoid hemorrhage, Clinical Sciences, Microdialysis, Public health systems and services research, Intensive Care Medicine, Brain Chemistry, Veterinary Emergency Medicine and Critical Care, and Neurointensive Care
Neuroprotective strategies that limit secondary tissue loss and/or improve functional outcomes have been identified in multiple animal models of ischemic, hemorrhagic, traumatic and nontraumatic cerebral lesions. However, use of these... more
Neuroprotective strategies that limit secondary tissue loss and/or improve functional outcomes have been identified in multiple animal models of ischemic, hemorrhagic, traumatic and nontraumatic cerebral lesions. However, use of these potential interventions in human randomized controlled studies has generally given disappointing results. In this paper, we summarize the current status in terms of neuroprotective strategies, both in the immediate and later stages of acute brain injury in adults. We also review potential new strategies and highlight areas for future research.
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Patient monitoring is routinely performed in all patients who receive neurocritical care. The combined use of monitors, including the neurologic examination, laboratory analysis, imaging studies, and physiological parameters, is common in... more
Patient monitoring is routinely performed in all patients who receive neurocritical care. The combined use of monitors, including the neurologic examination, laboratory analysis, imaging studies, and physiological parameters, is common in a platform called multi-modality monitoring (MMM). However, the full potential of MMM is only beginning to be realized since for the most part, decision making historically has focused on individual aspects of physiology in a largely threshold-based manner. The use of MMM now is being facilitated by the evolution of bio-informatics in critical care including developing techniques to acquire, store, retrieve, and display integrated data and new analytic techniques for optimal clinical decision making. In this review, we will discuss the crucial initial steps toward data and information management, which in this emerging era of data-intensive science is already shifting concepts of care for acute brain injury and has the potential to both reshape how...
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Research Interests: Neurosurgery, Traumatic Brain Injury, Medicine, Coma, Brain, and 15 moreHumans, Anoxia, Female, Male, Anesthesia, Glasgow Coma Scale, Clinical Sciences, Intensive Care Unit, Middle Aged, Oxygen, Retrospective Studies, X ray Computed Tomography, Neurosciences, Intracranial Pressure, and Cerebral perfusion pressure
Object Cerebral pressure autoregulation is an important neuroprotective mechanism that stabilizes cerebral blood flow when blood pressure (BP) changes. In this study the authors examined the association between autoregulation and clinical... more
Object Cerebral pressure autoregulation is an important neuroprotective mechanism that stabilizes cerebral blood flow when blood pressure (BP) changes. In this study the authors examined the association between autoregulation and clinical factors, BP, intracranial pressure (ICP), brain tissue oxygen tension (PbtO2), and outcome after pediatric severe traumatic brain injury (TBI). In particular we examined how the status of autoregulation influenced the effect of BP changes on ICP and PbtO2. Methods In this prospective observational study, 52 autoregulation tests were performed in 24 patients with severe TBI. The patients had a mean age of 6.3 ± 3.2 years, and a postresuscitation Glasgow Coma Scale score of 6 (range 3–8). All patients underwent continuous ICP and PbtO2 monitoring, and transcranial Doppler ultrasonography was used to examine the autoregulatory index (ARI) based on blood flow velocity of the middle cerebral artery after increasing mean arterial pressure by 20% of the b...
Research Interests: Neurology, Neurosurgery, Medicine, Linear models, Humans, and 15 moreChild, Blood Pressure, Female, Male, Anesthesia, Autoregulation, Glasgow Coma Scale, Infant, Homeostasis, Intracranial Pressure, Cerebral autoregulation, Brain injuries, Child preschool, glasgow outcome scale, and Arterial pressure
Background and Purpose— The optimal hemoglobin (Hgb) target after aneurysmal subarachnoid hemorrhage is not precisely known. We sought to examine the threshold of Hgb concentration associated with an increased risk of cerebral metabolic... more
Background and Purpose— The optimal hemoglobin (Hgb) target after aneurysmal subarachnoid hemorrhage is not precisely known. We sought to examine the threshold of Hgb concentration associated with an increased risk of cerebral metabolic dysfunction in patients with poor-grade subarachnoid hemorrhage. Methods— Twenty consecutive patients with poor-grade subarachnoid hemorrhage who underwent multimodality neuromonitoring (intracranial pressure, brain tissue oxygen tension, cerebral microdialysis) were studied prospectively. Brain tissue oxygen tension and extracellular lactate/pyruvate ratio were used as markers of cerebral metabolic dysfunction and the relationship between Hgb concentrations and the incidence of brain hypoxia (defined by a brain tissue oxygen tension <20 mm Hg) and cell energy dysfunction (defined by a lactate/pyruvate ratio >40) was analyzed. Results— Compared with higher Hgb concentrations, a Hgb concentration <9 g/dL was associated with lower brain tissue...
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BACKGROUND Increased intracranial pressure (ICP) can cause brain ischemia and compromised brain oxygen (PbtO2 ≤ 20 mm Hg) after severe traumatic brain injury (TBI). OBJECTIVE We examined whether decompressive craniectomy (DC) to treat... more
BACKGROUND Increased intracranial pressure (ICP) can cause brain ischemia and compromised brain oxygen (PbtO2 ≤ 20 mm Hg) after severe traumatic brain injury (TBI). OBJECTIVE We examined whether decompressive craniectomy (DC) to treat elevated ICP reduces the cumulative ischemic burden (CIB) of the brain and therapeutic intensity level (TIL). METHODS Ten severe TBI patients (mean age, 31.4 ± 14.2 years) who had continuous PbtO2 monitoring before and after delayed DC were retrospectively identified. Patients were managed according to the guidelines for the management of severe TBI. The CIB was measured as the total time spent between a PbtO2 of 15 to 20, 10 to 15, and 0 to 10 mm Hg. The TIL was calculated every 12 hours. Mixed-effects models were used to estimate changes associated with DC. RESULTS DC was performed on average 2.8 days after admission. DC was found to immediately reduce ICP (mean [SEM] decrease was 7.86 mm Hg [2.4 mm Hg]; P = .005). TIL, which was positively correlate...
Research Interests: Neurosurgery, Medicine, Humans, Female, Male, and 15 moreAnesthesia, Clinical Sciences, Middle Aged, Oxygen, Adult, Retrospective Studies, Intracranial Hypertension, Oxygen Consumption, Neurosciences, Intracranial Pressure, Decompressive Craniectomy, Postoperative Period, Cumulant, Brain injuries, and Craniotomy
Research Interests: Carbon Dioxide, Medicine, Brain, Humans, Child, and 15 moreFemale, Male, Anesthesia, Glasgow Coma Scale, Infant, Clinical Sciences, Hyperoxia, Neurosciences, Neurocritical Care, Intracranial Pressure, Confidence Interval, Brain injuries, Child preschool, Cerebral perfusion pressure, and Fraction of inspired oxygen
Research Interests: Critical Care, Brain, Humans, Blood Pressure, Female, and 15 moreAnesthesia, Cohort Study, Glasgow Coma Scale, Analgesia, Clinical Sciences, Aged, Head injury, Adult, Fluid Therapy, Hospital Mortality, Conscious Sedation, Brain injuries, Combined Modality Therapy, Craniotomy, and Cerebral perfusion pressure
Research Interests: Natural History, Medicine, Critical Care, Literature Review, Humans, and 15 moreCentral Nervous System, Incidence, Interventional Neuroradiology, Clinical Sciences, Intensive Care Unit, Fever, Intensive Care Medicine, Multidisciplinary Teams, Aneurysm, Multidisciplinary Approach, Hyponatremia, Neurocritical Care, Acute Disease, Endovascular, and Neurointensive Care
Research Interests: Medicine, Critical Care, Literature Review, Erythropoietin, Humans, and 15 moreAnemia, Disease Severity, Randomized Trial, Clinical Sciences, Oxygen Delivery, Cerebral Ischemia, Intensive Care Medicine, Blood Transfusion, Observational Study, Literature Search, Cerebral Blood Flow, Neurosciences, Neurocritical Care, Cerebral Vasospasm, and Acute Disease
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Object The object of this study was to determine whether brain tissue oxygen (PbtO2)–based therapy or intracranial pressure (ICP)/cerebral perfusion pressure (CPP)–based therapy is associated with improved patient outcome after severe... more
Object The object of this study was to determine whether brain tissue oxygen (PbtO2)–based therapy or intracranial pressure (ICP)/cerebral perfusion pressure (CPP)–based therapy is associated with improved patient outcome after severe traumatic brain injury (TBI). Methods Seventy patients with severe TBI (postresuscitation GCS score ≤ 8), admitted to a neurosurgical intensive care unit at a university-based Level I trauma center and tertiary care hospital and managed with an ICP and PbtO2 monitor (mean age 40 ± 19 years [SD]) were compared with 53 historical controls who received only an ICP monitor (mean age 43 ± 18 years). Therapy for both patient groups was aimed to maintain ICP < 20 mm Hg and CPP > 60 mm Hg. Patients with PbtO2 monitors also had therapy to maintain PbtO2 > 20 mm Hg. Results Data were obtained from 12,148 hours of continuous ICP monitoring and 6,816 hours of continuous PbtO2 monitoring. The mean daily ICP and CPP and the frequency of elevated ICP (> 2...
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Object. An intracranial pressure (ICP) monitor, from which cerebral perfusion pressure (CPP) is estimated, is recommended in the care of severe traumatic brain injury (TBI). Nevertheless, optimal ICP and CPP management may not always... more
Object. An intracranial pressure (ICP) monitor, from which cerebral perfusion pressure (CPP) is estimated, is recommended in the care of severe traumatic brain injury (TBI). Nevertheless, optimal ICP and CPP management may not always prevent cerebral ischemia, which adversely influences patient outcome. The authors therefore determined whether the addition of a brain tissue oxygen tension (PO2) monitor in the treatment of TBI was associated with an improved patient outcome. Methods. Patients with severe TBI (Glasgow Coma Scale [GCS] score < 8) who had been admitted to a Level I trauma center were evaluated as part of a prospective observational database. Patients treated with ICP and brain tissue PO2 monitoring were compared with historical controls matched for age, pathological features, admission GCS score, and Injury Severity Score who had undergone ICP monitoring alone. Therapy in both patient groups was aimed at maintaining an ICP less than 20 mm Hg and a CPP greater than 60...
Research Interests: Neurosurgery, Medicine, Brain, Humans, Female, and 15 moreMale, Anesthesia, Glasgow Coma Scale, Clinical Sciences, Middle Aged, Oxygen, Adult, Cerebral Ischemia, Neurosciences, Intracranial Pressure, Mortality rate, Brain injuries, Severity of Illness Index, Injury Severity Score, and Cerebral perfusion pressure
✓ Jugular bulb oxygen monitoring can be used to estimate the adequacy of cerebral blood flow to support cerebral metabolism after severe head injury. In the present study, the authors studied the cerebral arteriovenous oxygen difference... more
✓ Jugular bulb oxygen monitoring can be used to estimate the adequacy of cerebral blood flow to support cerebral metabolism after severe head injury. In the present study, the authors studied the cerebral arteriovenous oxygen difference (AVDO2) before and after treatment in 32 head-injured patients (Glasgow Coma Scale scores ≤ 8) to examine the relationships among AVDO2 and cerebral perfusion pressure (CPP), delayed cerebral infarction, and outcome. Fifteen patients (Group A) underwent craniotomy for hematoma evacuation and 17 (Group B) received mannitol for sustained intracranial hypertension (intracranial pressure > 20 mm Hg, > 10 minutes). Radiographic evidence of delayed cerebral infarction was observed in 14 patients. Overall, 17 patients died or were severely disabled. Cerebral AVDO2 was elevated before craniotomy or mannitol administration; the mean AVDO2 for all patients before treatment was 8.6 ± 1.8 vol%. Following craniotomy or mannitol administration, the AVDO2 dec...
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Object. Medically intractable intracranial hypertension is a major cause of morbidity and mortality after severe brain injury. One potential treatment for intracranial hypertension is decompressive hemicraniectomy (DCH). Whether and when... more
Object. Medically intractable intracranial hypertension is a major cause of morbidity and mortality after severe brain injury. One potential treatment for intracranial hypertension is decompressive hemicraniectomy (DCH). Whether and when to use DCH, however, remain unclear. The authors therefore studied the effects of DCH on cerebral O2 to develop a better understanding of the effects of this treatment on the recovery from injury and disease. Methods. The study focused on seven patients (mean age 30.6 ± 9.7 years) admitted to the hospital after traumatic brain injury (five patients) or subarachnoid hemorrhage (two patients) as part of a prospective observational database at a Level I trauma center. At admission the Glasgow Coma Scale (GCS) score was 6 or less in all patients. Patients received continuous monitoring of intracranial pressure (ICP), cerebral perfusion pressure (CPP), blood pressure, and arterial O2 saturation. Cerebral oxygenation was measured using the commercially av...
Research Interests: Neurosurgery, Medicine, Humans, Female, Male, and 15 moreAnesthesia, Glasgow Coma Scale, Clinical Sciences, Middle Aged, Oxygen, Adult, Intracranial Hypertension, Oxygen Consumption, Neurosciences, Intracranial Pressure, Oxygenation, Postoperative Period, Functional Laterality, Brain injuries, and Cerebral perfusion pressure
Object. Nimodipine has been shown to improve neurological outcome after subarachnoid hemorrhage (SAH); the mechanism of this improvement, however, is uncertain. In addition, adverse systemic effects such as hypotension have been... more
Object. Nimodipine has been shown to improve neurological outcome after subarachnoid hemorrhage (SAH); the mechanism of this improvement, however, is uncertain. In addition, adverse systemic effects such as hypotension have been described. The authors investigated the effect of nimodipine on brain tissue PO2. Methods. Patients in whom Hunt and Hess Grade IV or V SAH had occurred who underwent aneurysm occlusion and had stable blood pressure were prospectively evaluated using continuous brain tissue PO2 monitoring. Nimodipine (60 mg) was delivered through a nasogastric or Dobhoff tube every 4 hours. Data were obtained from 11 patients and measurements of brain tissue PO2, intracranial pressure (ICP), mean arterial blood pressure (MABP), and cerebral perfusion pressure (CPP) were recorded every 15 minutes. Nimodipine resulted in a significant reduction in brain tissue PO2 in seven (64%) of 11 patients. The baseline PO2 before nimodipine administration was 38.4 ± 10.9 mm Hg. The baseli...
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Research Interests: Emergency Medicine, Neurology, Neurosurgery, Anesthesiology, Critical, and 15 moreMedicine, Critical Care, General Surgery, Canada, Humans, Internal Medicine, INTENSIVE CARE, Medicine and Health Sciences, Clinical Protocols, Cross Sectional Studies, Hemoglobins, Health Care Surveys, Neurointensive Care, Medical and Health Sciences, and Erythrocyte transfusion
The field of neuromonitoring has grown rapidly over the past 30 years, which has helped improve pathophysiological understanding, clinical care and outcomes for patients with primary ABI, including traumatic brain injury (TBI),... more
The field of neuromonitoring has grown rapidly over the past 30 years, which has helped improve pathophysiological understanding, clinical care and outcomes for patients with primary ABI, including traumatic brain injury (TBI), subarachnoid haemorrhage (SAH), hypoxic-ischaemic injury and ischaemic or haemorrhagic stroke. The main goals of neuromonitoring are to better understand a patient’s cerebral physiology, provide early detection of neurological worsening or cerebral dysfunction to avoid progression to irreversible neurological injury, and assist with neuroprognostication. This is accomplished through a combination of serial neurological examinations, neuroimaging studies, and continuously monitoring different neurophysiological parameters. Numerous expert opinion and evidence-based reviews on the role of multimodality neuromonitoring in ABI have been published, including a consensus statement on multimodality monitoring in neurocritical care from the Neurocritical Care Society...
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Background: Many randomized controlled trials (RCT) have assessed new treatments in subarachnoid hemorrhage (SAH), yet most show no treatment efficacy. One explanation is the statistical analysis of the primary endpoint was not as... more
Background: Many randomized controlled trials (RCT) have assessed new treatments in subarachnoid hemorrhage (SAH), yet most show no treatment efficacy. One explanation is the statistical analysis of the primary endpoint was not as efficient as possible. We reanalyzed SAH RCTs with various statistical tests to determine whether the statistical method affects RCT primary outcome.Methods: Individual patient data for the primary outcome (Glasgow outcome scale [GOS]) of two SAH RCTs were analyzed using 15 statistical methods. For tests requiring outcome dichotomization, multiple cut-points in the 5-level GOS were assessed. Next, a synthetic dataset generated using random sampling with replacement from ten SAH RCTs was assessed using the same statistical tests. A Friedman test (two-way non-parametric analysis of variance) determined which tests produced the highest average absolute Z-values. The number of times each test reported significance of p<0.05 across the different datasets was...
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Objectives: To estimate the impact of goal-directed therapy on outcome after traumatic brain injury, our team applied goal-directed therapy to standardize care in patients with moderate to severe traumatic brain injury, who were enrolled... more
Objectives: To estimate the impact of goal-directed therapy on outcome after traumatic brain injury, our team applied goal-directed therapy to standardize care in patients with moderate to severe traumatic brain injury, who were enrolled in a large multicenter clinical trial. Design: Planned secondary analysis of data from Progesterone for the Treatment of Traumatic Brain Injury III, a large, prospective, multicenter clinical trial. Setting: Forty-two trauma centers within the Neurologic Emergencies Treatment Trials network. Patients: Eight-hundred eighty-two patients were enrolled within 4 hours of injury after nonpenetrating traumatic brain injury characterized by Glasgow Coma Scale score of 4–12. Measurements and Main Results: Physiologic goals were defined a priori in order to standardize care across 42 sites participating in Progesterone for the Treatment of Traumatic Brain Injury III. Physiologic data collection occurred hourly; laboratory data were collected according to loca...
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To develop and validate a set of practical prediction tools that reliably estimate the outcome of subarachnoid haemorrhage from ruptured intracranial aneurysms (SAH). Cohort study with logistic regression analysis to combine predictors... more
To develop and validate a set of practical prediction tools that reliably estimate the outcome of subarachnoid haemorrhage from ruptured intracranial aneurysms (SAH). Cohort study with logistic regression analysis to combine predictors and treatment modality. Subarachnoid Haemorrhage International Trialists' (SAHIT) data repository, including randomised clinical trials, prospective observational studies, and hospital registries. Researchers collaborated to pool datasets of prospective observational studies, hospital registries, and randomised clinical trials of SAH from multiple geographical regions to develop and validate clinical prediction models. Predicted risk of mortality or functional outcome at three months according to score on the Glasgow outcome scale. Clinical prediction models were developed with individual patient data from 10 936 patients and validated with data from 3355 patients after development of the model. In the validation cohort, a core model including pat...
Research Interests: Computer Science, Neuroimaging, Clinical Trial, Medicine, Logistic Regression, and 15 moreProspective studies, Humans, Cohort, Registries, BMJ, Prognosis, Observational Study, Receiver Operating Characteristic, Confidence Interval, Cohort Studies, Randomized Controlled Trials as Topic, Prospective Cohort Study, glasgow outcome scale, Intracranial aneurysm, and Patient Outcome Assessment
BACKGROUND Seizure is a significant complication in patients under acute admission for aneurysmal SAH and could result in poor outcomes. Treatment strategies to optimize management will benefit from methods to better identify at-risk... more
BACKGROUND Seizure is a significant complication in patients under acute admission for aneurysmal SAH and could result in poor outcomes. Treatment strategies to optimize management will benefit from methods to better identify at-risk patients. OBJECTIVE To develop and validate a risk score for convulsive seizure during acute admission for SAH. METHODS A risk score was developed in 1500 patients from a single tertiary hospital and externally validated in 852 patients. Candidate predictors were identified by systematic review of the literature and were included in a backward stepwise logistic regression model with in-hospital seizure as a dependent variable. The risk score was assessed for discrimination using the area under the receiver operator characteristics curve (AUC) and for calibration using a goodness-of-fit test. RESULTS The SAFARI score, based on 4 items (age ≥ 60 yr, seizure occurrence before hospitalization, ruptured aneurysm in the anterior circulation, and hydrocephalus...
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Risk of delayed cerebral ischemia (DCI) in patients with aneurysmal subarachnoid hemorrhage (aSAH) with asymptomatic angiographic vasospasm on admission is unclear in the literature. The goal of this study is to identify predictors of... more
Risk of delayed cerebral ischemia (DCI) in patients with aneurysmal subarachnoid hemorrhage (aSAH) with asymptomatic angiographic vasospasm on admission is unclear in the literature. The goal of this study is to identify predictors of clinical DCI in this group of patients. An exploratory subgroup analysis was conducted in the SAHIT (Subarachnoid Hemorrhage International Trialists) data repository to identify predictors of clinical DCI in patients with good-grade aSAH (World Federation of Neurological Surgeons grade I and II) with angiographic vasospasm on admission. Predictors considered include age, sex, systolic blood pressure at presentation, World Federation of Neurological Surgeon grade, Fisher grade, aneurysm size and location, treatment modality, hydrocephalus requiring external ventricular drain insertion, and severity of vasospasm. The predictors were ranked based on dominance analysis with R(2) as fit statistics and assessed in a set of logistic regression analysis models. Four data sets out of 16 studies in the SAHIT database were analyzed, with a total of 4125 patients. One hundred and ninety-one patients (4.6%) had asymptomatic angiographic vasospasm at admission. Of those, 78 patients (40.8%) developed clinical DCI. Univariate analysis showed significant associations between severe vasospasm on admission and development of clinical DCI (odds ratio, 9.5, 95% confidence interval, 2.07-43.50; P = 0.004). None of the studied predictors was associated with the development of clinical DCI on multivariate analysis. Asymptomatic angiographic vasospasm in patients with good-grade aSAH on admission is uncommon. Further studies are needed to identify high-risk patients for the development of DCI in the context of asymptomatic early vasospasm.
Research Interests: Surgery, Clinical Trials, Medicine, Humans, Journal Article, and 14 moreSubarachnoid hemorrhage, Brain Ischemia, Clinical Neurology, Risk factors, Patient Admission, Odds ratio, Risk Factors, Asymptomatic, Univariate Analysis, Predictive value of tests, Cerebral Angiography, Cerebral Vasospasm, Randomized Controlled Trials as Topic, and Vasospasm
Patients admitted to the neurocritical care unit (NCCU) are at risk for secondary brain injury that frequently can exacerbate outcome. Consequently, current NCCU management strategies focus on the identification, prevention, and... more
Patients admitted to the neurocritical care unit (NCCU) are at risk for secondary brain injury that frequently can exacerbate outcome. Consequently, current NCCU management strategies focus on the identification, prevention, and management of secondary brain injury, since there are few pharmacological agents that demonstrate efficacy in these patients. In the last decade, techniques to monitor brain function have evolved and, in the modern NCCU, play an important role in patient care and in particular in a patient-specific targeted approach. Monitors include radiologic techniques that provide information about a specific point in time or bedside monitors that provide continuous or noncontinuous physiologic information. In turn, these bedside techniques may be subdivided into invasive or noninvasive monitors. In this review we will discuss invasive intracranial monitors including (1) intracranial pressure; (2) monitors of cerebral oxygenation (direct measurement of brain oxygen [PbtO2] and jugular venous catheters); (3) metabolic monitors, i.e., cerebral microdialysis; and (4) cerebral blood flow monitors such as thermal diffusion flowmetry and laser Doppler flowmetry.
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Traumatic brain injury (TBI) is a major cause of death and disability worldwide. In large part critical care for TBI is focused on the identification and management of secondary brain injury. This requires effective neuromonitoring that... more
Traumatic brain injury (TBI) is a major cause of death and disability worldwide. In large part critical care for TBI is focused on the identification and management of secondary brain injury. This requires effective neuromonitoring that traditionally has centered on intracranial pressure (ICP). The purpose of this paper is to review the fundamental literature relative to the clinical application of ICP monitoring in TBI critical care and to provide recommendations on how the technique maybe applied to help patient management and enhance outcome. A PubMed search between 1980 and September 2013 identified 2,253 articles; 244 of which were reviewed in detail to prepare this report and the evidentiary tables. Several important concepts emerge from this review. ICP monitoring is safe and is best performed using a parenchymal monitor or ventricular catheter. While the indications for ICP monitoring are well established, there remains great variability in its use. Increased ICP, particular...
Research Interests: Traumatic Brain Injury, Medicine, Critical Care, Coma, Humans, and 13 moreBrain injury, Clinical Sciences, Prognosis, Neurologie, Intensive Care Medicine, Neurosciences, Neurocritical Care, Intracranial Pressure, Intraoperative Neurophysiological Monitoring, Multimodality Monitoring, Brain injuries, Patient selection, and Cerebral perfusion pressure
Traumatic brain injury (TBI) is a major cause of morbidity and mortality worldwide. Despite encouraging animal research, pharmacological agents and neuroprotectants have disappointed in the clinical environment. Current TBI management... more
Traumatic brain injury (TBI) is a major cause of morbidity and mortality worldwide. Despite encouraging animal research, pharmacological agents and neuroprotectants have disappointed in the clinical environment. Current TBI management therefore is directed towards identification, prevention, and treatment of secondary cerebral insults that are known to exacerbate outcome after injury. This strategy is based on a variety of monitoring techniques that include the neurological examination, imaging, laboratory analysis, and physiological monitoring of the brain and other organ systems used to guide therapeutic interventions. Recent clinical series suggest that TBI management informed by multimodality monitoring is associated with improved patient outcome, in part because care is provided in a patient-specific manner. In this review we discuss physiological monitoring of the brain after TBI and the emerging field of neurocritical care bioinformatics.
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OPINION STATEMENT: Anemia develops in about 50% of patients hospitalized with traumatic brain injury (TBI) and is recognized as a cause of secondary brain injury. This review examines the effects of anemia and transfusion on TBI patients... more
OPINION STATEMENT: Anemia develops in about 50% of patients hospitalized with traumatic brain injury (TBI) and is recognized as a cause of secondary brain injury. This review examines the effects of anemia and transfusion on TBI patients through a literature search to identify original research on anemia and transfusion in TBI, the effects of transfusion on brain physiology, and the role of erythropoietin or hemoglobin-based blood substitutes (HBBSs). However, the amount of high-quality, prospective data available to help make decisions about when TBI patients should be transfused is very small. Randomized transfusion trials have involved far too few TBI patients to reach definitive conclusions. Thus, it is hardly surprising that there is widespread practice variation. In our opinion, a hemoglobin transfusion threshold of 7 g/dL cannot yet be considered safe for TBI patients admitted to hospital, and in particular to the ICU, as it is for other critically ill patients. Red blood cel...
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Research Interests: Evidence Based Medicine, Traumatic Brain Injury, Clinical Trial, Adolescent, Medicine, and 15 moreHumans, Female, Male, Middle Aged, Adult, Randomized Controlled Trial, Survival Rate, Prognosis, Intensive Care Medicine, Intracranial Hypertension, Intracranial Pressure, Brain injuries, Multicenter Studies as Topic, Randomized Controlled Trials as Topic, and Cerebral perfusion pressure
The outcome of patients with aneurysmal subarachnoid hemorrhage (SAH) has improved slowly over the past 25 years. This improvement may be due to early aneurysm repair by endovascular or open means, use of nimodipine, and better critical... more
The outcome of patients with aneurysmal subarachnoid hemorrhage (SAH) has improved slowly over the past 25 years. This improvement may be due to early aneurysm repair by endovascular or open means, use of nimodipine, and better critical care management. Despite this improvement, mortality remains at about 40%, and many survivors have permanent neurologic, cognitive, and neuropsychologic deficits. Randomized clinical trials have tested pharmacologic therapies, but few have been successful. There are numerous explanations for the failure of these trials, including ineffective interventions, inadequate sample size, treatment side effects, and insensitive or inappropriate outcome measures. Outcome often is evaluated on a good-bad dichotomous scale that was developed for traumatic brain injury 40 years ago. To address these issues, we established the Subarachnoid Hemorrhage International Trialists (SAHIT) data repository. The primary aim of the SAHIT data repository is to provide a uniqu...
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Outcome of patients with aneurysmal subarachnoid hemorrhage (SAH) has improved over the last decades. Yet, case fatality remains nearly 40% and survivors often have permanent neurological, cognitive and/or behavioural sequelae. Other than... more
Outcome of patients with aneurysmal subarachnoid hemorrhage (SAH) has improved over the last decades. Yet, case fatality remains nearly 40% and survivors often have permanent neurological, cognitive and/or behavioural sequelae. Other than nimodipine drug or clinical trials have not consistently improved outcome. We formed a collaboration of SAH investigators to create a resource for prognostic analysis and for studies aimed at optimizing the design and analysis of phase 3 trials in aneurysmal SAH. We identified investigators with data from randomized, clinical trials of patients with aneurysmal SAH or prospectively collected single- or multicentre databases of aneurysmal SAH patients. Data are being collected and proposals to use the data and to design future phase 3 clinical trials are being discussed. This paper reviews some issues discussed at the first meeting of the SAH international trialists (SAHIT) repository meeting. Investigators contributed or have agreed to contribute da...
Research Interests: Clinical Trial, Treatment Outcome, Medicine, Critical Care, Antioxidants, and 14 moreHumans, Subarachnoid hemorrhage, Sample Size, Pyridines, Combination drug therapy, Hypotension, Aneurysm, NIMODIPINE, Neuroprotective Agents, Calcium Channel Blockers, Randomized Controlled Trials as Topic, Tetrazoles, Intracranial aneurysm, and Sulfonamides
Research Interests: Evidence Based Medicine, Clinical Trials, Biomarkers, Electroencephalography, Critical Care, and 15 moreHumans, Bio Informatics, Consensus, INTENSIVE CARE, Data Collection, Clinical Sciences, Intensive Care Unit, Brain metabolism, Internationality, Clinical Guidelines, Intensive Care Medicine, Brain Physiology, Blood gas analysis, Clinical Protocols, and Brain injuries
Retrospective medical record review and literature review. To identify cases where a cerebrospinal fluid (CSF) leak occurred during an anterior cervical discectomy and fusion (ACDF) and to create a management algorithm based on the... more
Retrospective medical record review and literature review. To identify cases where a cerebrospinal fluid (CSF) leak occurred during an anterior cervical discectomy and fusion (ACDF) and to create a management algorithm based on the findings. ACDF is a commonly performed spinal operation. It is effective with very low complication rates. One rare complication of ACDF is a CSF leak. There is limited information on the management of CSF leaks after ACDF and management is on a surgeon-by-surgeon basis. We reviewed 3 surgeons&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; case logs and identified cases where a CSF leak was encountered during ACDF and reviewed the patients&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; medical records, operative reports and imaging to determine how these leaks were managed. We also performed a PubMed search for articles about the presentation and management of CSF leaks after ACDF. Thirteen CSF leaks were identified in 1223 ACDFs, corresponding to a CSF leak rate of 1%. Of these, 9 were successfully treated with intraoperative repair. Postoperative lumbar drainage was used in the remaining 4 patients and was successful in 1 patient. Three patients underwent neck re-exploration and attempted delayed repair. Three patients, including one who was found to have hydrocephalus, ultimately required continuous CSF diversion via shunting. We identified 7 case reports of CSF leak in ADCF in the literature and 1 article that reviewed the prevalence and management of this complication. CSF leak after ACDF is an uncommon complication that can usually be repaired. We provide a stepwise management strategy for CSF leaks in ACDF.
Research Interests: Surgery, Biomedical Engineering, Spine, Treatment Outcome, Medicine, and 15 moreCerebrospinal Fluid, Complication, Humans, Female, Male, Cervical Vertebrae, Clinical Sciences, Middle Aged, Adult, Retrospective Studies, Leak, Spinal Fusion, Postoperative Complications, Diskectomy, and Anterior cervical discectomy and fusion
Research Interests:
Microdialysis, an in vivo technique that permits collection and analysis of small molecular weight substances from the interstitial space, was developed more than 30 years ago and introduced into the clinical neurosciences in the 1990s.... more
Microdialysis, an in vivo technique that permits collection and analysis of small molecular weight substances from the interstitial space, was developed more than 30 years ago and introduced into the clinical neurosciences in the 1990s. Today cerebral microdialysis is an established, commercially available clinical tool that is focused primarily on markers of cerebral energy metabolism (glucose, lactate, and pyruvate) and cell damage (glycerol), and neurotransmitters (glutamate). Although the brain comprises only 2% of body weight, it consumes 20% of total body energy. Consequently, the ability to monitor cerebral metabolism can provide significant insights during clinical care. Measurements of lactate, pyruvate, and glucose give information about the comparative contributions of aerobic and anaerobic metabolisms to brain energy. The lactate/pyruvate ratio reflects cytoplasmic redox state and thus provides information about tissue oxygenation. An elevated lactate pyruvate ratio (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;40) frequently is interpreted as a sign of cerebral hypoxia or ischemia. However, several other factors may contribute to an elevated LPR. This article reviews potential non-hypoxic/ischemic causes of an increased LPR.
Research Interests: Medicine, Critical Care, Energy Metabolism, Anaerobic Metabolism, Glutamate, and 15 moreBrain, Humans, Blood Glucose, Ischemia, Clinical Sciences, Glycerol, Microdialysis, Anaerobic Exercise, Body Weight, Molecular weight, Lactic Acid, Glutamic Acid, Glutamate Receptor, Brain injuries, and Interstitial fluid
We analyzed the impact of shivering on brain tissue oxygenation (PbtO(2)) during induced normothermia in patients with severe brain injury. We studied patients with severe brain injury who developed shivering during induced normothermia.... more
We analyzed the impact of shivering on brain tissue oxygenation (PbtO(2)) during induced normothermia in patients with severe brain injury. We studied patients with severe brain injury who developed shivering during induced normothermia. Induced normothermia was applied to treat refractory fever (body temperature [BT] &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; or =38.3 degrees C, refractory to conventional treatment) using a surface cooling device with computerized adjustment of patient BT target to 37 +/- 0.5 degrees C. PbtO(2), intracranial pressure, mean arterial pressure, cerebral perfusion pressure, and BT were monitored continuously. Circulating water temperature of the device system was measured to assess the intensity of cooling. Fifteen patients (10 with severe traumatic brain injury, 5 with aneurysmal subarachnoid hemorrhage) were treated with induced normothermia for an average of 5 +/- 2 days. Shivering caused a significant decrease in PbtO(2) levels both in SAH and TBI patients. Compared to baseline, shivering was associated with an overall reduction of PbtO(2) from 34.1 +/- 7.3 to 24.4 +/- 5.5 mmHg (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). A significant correlation was found between the magnitude of shivering-associated decrease of PbtO(2) (DeltaPbtO(2)) and circulating water temperature (R = 0.82, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). In patients with severe brain injury treated with induced normothermia, shivering was associated with a significant decrease of PbtO(2), which correlated with the intensity of cooling. Monitoring of therapeutic cooling with computerized thermoregulatory systems may help prevent shivering and optimize the management of induced normothermia. The clinical significance of shivering-induced decrease in brain tissue oxygenation remains to be determined.
Research Interests: Adolescent, Medicine, Critical Care, Cryotherapy, Hypothermia, and 15 moreBrain, Humans, Female, Male, Anesthesia, Body temperature regulation, Brain injury, Body Temperature, Clinical Sciences, Adult, Fever, Intracranial Pressure, Brain injuries, Mean Arterial Pressure, and Cerebral perfusion pressure
Clinical prediction models can enhance clinical decision-making and research. However, available prediction models in aneurysmal subarachnoid hemorrhage (aSAH) are rarely used. We evaluated the methodological validity of SAH prediction... more
Clinical prediction models can enhance clinical decision-making and research. However, available prediction models in aneurysmal subarachnoid hemorrhage (aSAH) are rarely used. We evaluated the methodological validity of SAH prediction models and the relevance of the main predictors to identify potentially reliable models and to guide future attempts at model development. We searched the EMBASE, MEDLINE, and Web of Science databases from January 1995 to June 2012 to identify studies that reported clinical prediction models for mortality and functional outcome in aSAH. Validated methods were used to minimize bias. Eleven studies were identified; 3 developed models from datasets of phase 3 clinical trials, the others from single hospital records. The median patient sample size was 340 (interquartile range 149-733). The main predictors used were age (n = 8), Fisher grade (n = 6), World Federation of Neurological Surgeons grade (n = 5), aneurysm size (n = 5), and Hunt and Hess grade (n = 3). Age was consistently dichotomized. Potential predictors were prescreened by univariate analysis in 36 % of studies. Only one study was penalized for model optimism. Details about model development were often insufficiently described and no published studies provided external validation. While clinical prediction models for aSAH use a few simple predictors, there are substantial methodological problems with the models and none have had external validation. This precludes the use of existing models for clinical or research purposes. We recommend further studies to develop and validate reliable clinical prediction models for aSAH.