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"Maas, A. I. R."
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Coagulation disorders after traumatic brain injury
Summary
Background.
Over the past decade new insights in our understanding of coagulation have identified the prominent role of tissue factor. The brain is rich in tissue factor, and injury to the brain may initiate disturbances in local and systemic coagulation. We aimed to review the current knowledge on the pathophysiology, incidence, nature, prognosis and treatment of coagulation disorders following traumatic brain injury (TBI).
Methods.
We performed a MEDLINE search from 1966 to April 2007 with various MESH headings, focusing on head trauma and coagulopathy. We identified 441 eligible English language studies. These were reviewed for relevance by two independent investigators. A meta-analysis was performed to calculate the frequencies of coagulopathy after TBI and to determine the association of coagulopathy and outcome, expressed as odds ratios.
Results.
Eighty-two studies were relevant for the purpose of this review. Meta-analysis of 34 studies reporting the frequencies of coagulopathy after TBI, showed an overall prevalence of 32.7%. The presence of coagulopathy after TBI was related both to mortality (OR 9.0; 95%CI: 7.3–11.6) and unfavourable outcome (OR 36.3; 95%CI: 18.7–70.5).
Conclusions.
We conclude that coagulopathy following traumatic brain injury is an important independent risk factor related to prognosis. Routine determination of the coagulation status should therefore be performed in all patients with traumatic brain injury. These data may have important implications in patient management. Well-performed prospective clinical trials should be undertaken as a priority to determine the beneficial effects of early treatment of coagulopathy.
Journal Article
Consensus statement from the international consensus meeting on post-traumatic cranioplasty
Background
Due to the lack of high-quality evidence which has hindered the development of evidence-based guidelines, there is a need to provide general guidance on cranioplasty (CP) following traumatic brain injury (TBI), as well as identify areas of ongoing uncertainty via a consensus-based approach.
Methods
The international consensus meeting on post-traumatic CP was held during the International Conference on Recent Advances in Neurotraumatology (ICRAN), in Naples, Italy, in June 2018. This meeting was endorsed by the Neurotrauma Committee of the World Federation of Neurosurgical Societies (WFNS), the NIHR Global Health Research Group on Neurotrauma, and several other neurotrauma organizations. Discussions and voting were organized around 5 pre-specified themes: (1) indications and technique, (2) materials, (3) timing, (4) hydrocephalus, and (5) paediatric CP.
Results
The participants discussed published evidence on each topic and proposed consensus statements, which were subject to ratification using anonymous real-time voting. Statements required an agreement threshold of more than 70% for inclusion in the final recommendations.
Conclusions
This document is the first set of practical consensus-based clinical recommendations on post-traumatic CP, focusing on timing, materials, complications, and surgical procedures. Future research directions are also presented.
Journal Article
Brain tissue oxygen response in severe traumatic brain injury
To investigate clinical relevance and prognostic value of brain tissue oxygen response (TOR: response of brain tissue pO(2) to changes in arterial pO(2)) in traumatic brain injury (TBI).
In a prospective cohort study TOR was investigated in 41 patients with severe TBI (Glasgow Coma Score < or =8) in whom continuous monitoring of brain tissue oxygen pressure (PbrO(2)) was performed.TOR was investigated each day over a five day period for 15 minutes by increasing FiO(2) on the ventilator setting. FiO(2) was increased directly from baseline to 1.0 for a period of 15 minutes under stable conditions (145 tests). In 34 patients the effect of decreasing PaCO(2) was evaluated on TOR by performing the same test after increasing inspiratory minute volume on the ventilator setting to 20% above baseline. Arterial blood gas analysis was performed before and after changing ventilator settings. Multimodality monitoring, including PbrO(2) was performed in all patients. Outcome at six months was evaluated according to the Glasgow Outcome Scale. For statistical analysis the Mann-whitney U-test was used for ordinally distributed variables, and the Chi-square test for categorical variables. Predictive value of TOR was analyzed in a multivariable model.
145 tests were available for analysis. Baseline PbrO(2) varied from 4.0 to 50 mmHg at PaO(2) values of 73-237 mmHg. At FiO(2) settings of 1.0, PbrO(2) varied from 9.1-200 mmHg and PaO(2) from 196-499 mmHg. Three distinct patterns of response were noted: response type A is characterized by a sharp increase in PbrO(2), reaching a plateau within several minutes; type B by the absence of a plateau, and type C by a short plateau phase followed by a subsequent further increase in PbrO(2). Patterns characterized by a stable plateau (type A), considered indicative of intact regulatory mechanisms, were seen more frequently from 48 hours after injury on. If present within the first 24 hours after injury such a response was related to more favorable outcome (p = 0.06). Mean TOR of all tests was 0.73 +/- 0.59 with an median TOR of 0.58. Patients with an unfavourable outcome had a higher TOR (1.03 +/- 0.60) during the first 24 hours, compared to patients with a favorable outcome (0.61 +/- 0.51; p = 0.02). Multiple logistic regression analysis supported the independent predictive value of tissue oxygen response for unfavorable outcome (odds ratio 4.8). During increased hyperventilation, mean TOR decreased substantially from 0.75 +/- 0.54 to 0.65 +/- 0.45 (p = 0.06; Wilcoxon test). Within the first 24 hours after injury a decrease in TOR following hyperventilation was significantly related to poorer outcome (p = 0.01).
Evaluation of TOR affords insight in (disturbances in) oxygen regulation after traumatic brain injury, is of prognostic value and may aid in identifying patients at (increased) risk for ischemia.
Journal Article
The Prognostic Importance of the Volume of Traumatic Epidural and Subdural Haematomas Revisited
The size of a traumatic intracranial haematoma at the moment of diagnosis can be impressive. Haematoma thickness is an inaccurate estimator of haematoma volume, and association with patient outcome is controversial. In this study computerized volumetry of offline digitized CT scans was used to relate haematoma volume with both patient characteristics on admission and at the six months outcome. This retrospective study covered the time period 1981/1990. Ninety eight patients operated upon for an epidural haematoma and 91 patients operated upon for an acute subdural haematoma were analyzed. The relative importance of clinical data, CT scan parameters, and calculated haematoma volumes was determined by multivariate analysis. Volume of the haematoma did not correlate with preoperative neurological condition or the six months outcome in either group, and consequently is not of additional prognostic value.
Journal Article
Serial Transcranial Doppler Measurements in Traumatic Brain Injury with Special Focus on the Early Posttraumatic Period
Cerebral ischemia is considered a key factor in the development of secondary damage after Traumatic Brain Injury (TBI). Studies on Cerebral Blood Flow (CBF) have documented decreased flow in over 50% of patients with TBI, studied in the acute phase. Transcranial Doppler (TCD) sonography is a non-invasive technique, permitting frequent or continuous measurements of blood flow velocity in the basal cerebral arteries.
To investigate the potential of TCD to detect decreased blood flow velocity in the early phase after TBI;To investigate whether flow velocity differs between hemispheres in patients with focal lesions versus those with more diffuse injuries;To investigate if decreased blood flow velocity is indicative of cerebral ischemia, as evidenced by measurements of brain tissue pO(2).
TCD examinations were performed in 57 patients with severe TBI (GCS
Journal Article
EBIC-Guidelines for management of severe head injury in adults
Guidelines for the management of severe head injury in adults as evolved by the European Brain Injury Consortium are presented and discussed. The importance of preventing and treating secondary insults is emphasized and the principles on which treatment is based are reviewed. Guidelines presented are of a pragmatic nature, based on consensus and expert opinion, covering the treatment from accident site to intensive care unit. Specific aspects pertaining to the conduct of clinical trials in head injury are highlighted. The adopted approach is further discussed in relation to other approaches to the development of guidelines, such as evidence based analysis.
Journal Article
Ethical considerations on consent procedures for emergency research in severe and moderate traumatic brain injury
Therapeutic trials in TBI are subject to principles of Good Clinical Practice (GCP), to national legislation, and to international and European ethical concepts and regulations [e.g. 13]. The guiding principles underlying these investigations of treatment are respect for autonomy of research subjects, protection against discomfort, risk, harm and exploitation and the prospect of some benefit. Patients with significant TBI are mentally incapacitated, thus prohibiting obtaining consent directly from the subject. Various approaches to consent procedures are used as surrogate to subject consent: proxy consent, consent by an independent physician and waiver of consent. These approaches are reviewed. A questionnaire soliciting opinions was mailed to 148 EBIC (European Brain Injury Consortium) associated neuro-trauma centers in 19 European countries. 48% respondents believe that relatives were not able to make a balanced decision, 72% believed that consent procedures are a significant factor causing decrease in enrollment rate and 83% stated that consent procedures delay initiation of study treatment, resulting in possible harm if the agent has shown to be effective. 64% of the respondents considered TBI an emergency situation in which clinical research could be initiated under the emergency exception for consent. In new European legislation, emergency research under waiver of consent is not permitted. Nevertheless, we consider that randomising patients with TBI into carefully evaluated trial protocols without prior consent may be considered ethically justified.
Journal Article
History of cervical spine surgery: from nihilism to advanced reconstructive surgery
Study design:
Review of literature.
Objectives:
To review and analyze the evolution of cervical spine surgery from ancient times to current practice. The aim is to present an accessible overview, primarily intended for a broad readership.
Methods:
Descriptive literature review and analysis of the development of cervical spine surgery from the prehistoric era until today.
Results:
The first evidence for surgical treatment of spinal disorders dates back to approximately 1500 BC. Conservative approaches to treatment have been the hallmark for thousands of years, but over the past 50 years progress has been rapid. We illustrate how nations have added elements to this complex subject and how knowledge has surpassed borders and language barriers. Transferral of knowledge occurred from Babylon (Bagdad) to Old Egypt, to the Greek and Roman empires and finally via the Middle East (Bagdad and Damascus) back to Europe. Recent advances in the field of anesthesia, imaging and spinal instrumentation have changed long-standing nihilism in the treatment of cervical spine pathologies to the current practice of advanced reconstructive surgery of the cervical spine. A critical approach to the evaluation of benefits and complications of these advanced surgical techniques for treatment of cervical spine disorders is required.
Conclusion:
Advances in surgery now permit full mechanical reconstruction of the cervical spine. However, despite substantial experimental progress, spinal cord repair and restoration of lost functions remain a challenge. Modern surgeons are still looking for the best way to manage spine disorders.
Journal Article
OBSERVER VARIATION IN THE ASSESSMENT OF OUTCOME IN TRAUMATIC BRAIN INJURY
Accurate and consistent outcome assessment is essential to randomized clinical trials. We aimed to explore observer variation in the assessment of outcome in a recently completed trial of dexanabinol in head injury and to consider steps to reduce such variation.
Eight hundred sixty-one patients with severe traumatic brain injury who were admitted to 86 centers were included in a multicenter, placebo-controlled, Phase III trial. Outcome was assessed at 3 and 6 months postinjury using the extended Glasgow Outcome Scale; standardized assessment was facilitated by the use of a structured interview. Before initiation of trial centers, outcome ratings were obtained for sample cases to establish initial levels of agreement. Training sessions in outcome assessment were held, and problems in assigning outcome were investigated. During the trial, a process of central review was established to monitor performance. Interobserver variation was analyzed using the kappa statistic.
Substantial observer variation was found in the rating of sample cases (weighted kappa, 0.72; confidence interval, 0.68-0.75) and in assigning outcome based on completed structured interviews (weighted kappa, 0.61; confidence interval, 0.57-0.64). In the early stages of the trial, a relatively large number of discrepancies (29-37%) were identified on central review. This number declined as the trial progressed and coincided with investigator training and feedback from central review. Centers with higher enrollment rates showed better performance.
Observer variation in outcome assessment is a significant problem for head injury trials. Consistency can be improved by standardizing procedures, training assessors, and monitoring the quality of assessments and providing feedback to interviewers.
Journal Article