Forewarning of hypotensive events using a Bayesian artificial neural network in neurocritical care.

Traumatically brain injured (TBI) patients are at risk from secondary insults. Arterial hypotension, critically low blood pressure, is one of the most dangerous secondary insults and is related to poor outcome in patients. The overall aim of this study was to get proof of the concept that advanced statistical techniques (machine learning) are methods that are able to provide early warning of impending hypotensive events before they occur during neuro-critical care. A Bayesian artificial neural network (BANN) model predicting episodes of hypotension was developed using data from 104 patients selected from the BrainIT multi-center database. Arterial hypotension events were recorded and defined using the Edinburgh University Secondary Insult Grades (EUSIG) physiological adverse event scoring system. The BANN was trained on a random selection of 50% of the available patients (n = 52) and validated on the remaining cohort. A multi-center prospective pilot study (Phase 1, n = 30) was then conducted with the system running live in the clinical environment, followed by a second validation pilot study (Phase 2, n = 49). From these prospectively collected data, a final evaluation study was done on 69 of these patients with 10 patients excluded from the Phase 2 study because of insufficient or invalid data. Each data collection phase was a prospective non-interventional observational study conducted in a live clinical setting to test the data collection systems and the model performance. No prediction information was available to the clinical teams during a patient's stay in the ICU. The final cohort (n = 69), using a decision threshold of 0.4, and including false positive checks, gave a sensitivity of 39.3% (95% CI 32.9-46.1) and a specificity of 91.5% (95% CI 89.0-93.7). Using a decision threshold of 0.3, and false positive correction, gave a sensitivity of 46.6% (95% CI 40.1-53.2) and specificity of 85.6% (95% CI 82.3-88.8). With a decision threshold of 0.3, > 15 min warning of patient instability can be achieved. We have shown, using advanced machine learning techniques running in a live neuro-critical care environment, that it would be possible to give neurointensive teams early warning of potential hypotensive events before they emerge, allowing closer monitoring and earlier clinical assessment in an attempt to prevent the onset of hypotension. The multi-centre clinical infrastructure developed to support the clinical studies provides a solid base for further collaborative research on data quality, false positive correction and the display of early warning data in a clinical setting.

Early warning of EUSIG-defined hypotensive events using a Bayesian Artificial Neural Network.

BACKGROUND: Hypotension is recognized as a potentially damaging secondary insult after traumatic brain injury. Systems to give clinical teams some early warning of likely hypotensive instability could be added to the range of existing techniques used in the management of this group of patients. By using the Edinburgh University Secondary Insult Grades (EUSIG) definitions for -hypotension (systolic arterial pressure <90 mmHg OR mean arterial -pressure <70 mmHg) we collected a group of ∼2,000 events by analyzing the Brain-IT database. We then constructed a Bayesian Artificial Neural Network (an advanced statistical modeling technique) that is able to provide some early warning when trained on this previously collected demographic and physiological data. MATERIALS AND METHODS: Using EUSIG defined event data from the Brain-IT database, we identified a Bayesian artificial neural network (BANN) topology and constructed a series of datasets using a group of clinically guided input variables. This allowed us to train a BANN, which was then tested on an unseen set of patients from the Brain-IT database. The initial tests used a particularly harsh assessment criterion whereby a true positive prediction was only allowed if the BANN predicted an upcoming event to the exact minute. We have now developed the system to the point where it is about to be used in a two-stage Phase II clinical trial and we are also researching a more realistic assessment technique. KEY RESULTS: We have constructed a BANN that is able to provide early warning to the clinicians based on a model that uses information from the physiological inputs; systolic and mean arterial pressure and heart rate; and demographic variables age and gender. We use 15-min SubWindows starting at 15 and 30 min before an event and process mean, slope and standard deviations. Based on 10 simulation runs, our current sensitivity is 36.25% (SE 1.31) with a specificity of 90.82% (SE 0.85). Initial results from a Phase I clinical study shows a model sensitivity of 40.95% (SE 6%) and specificity of 86.46% (SE 3%) Although this figure is low it is considered clinically useful for this dangerous condition, provided the false positive rate can be kept sufficiently low as to be practical in an intensive care environment. CONCLUSION: We have shown that using advanced statistical modeling techniques can provide clinical teams with useful information that will assist clinical care.

Trigger characteristics of EUSIG-defined hypotensive events.

BACKGROUND: Hypotension is a recognized -secondary insult after traumatic brain injury (TBI). There are many definitions of hypotension, an often cited example being the Brain Trauma Foundation's current (2007) "Guidelines for the Management of Severe Traumatic Brain Injury," which defines hypotension as systolic pressure <90 mmHg. However, this same document declares "The importance of mean arterial pressure, as opposed to systolic pressure should also be stressed, …." Our work shows that when using the Edinburgh University Secondary Insult Grades (EUSIG) definitions, which require monitoring of both systolic and mean arterial pressures, that most hypotensive events are in fact triggered by a breach of the mean arterial level of 70 mmHg. We suggest that close monitoring of mean arterial pressure would enable clinical teams to avoid more potentially damaging hypotensive events. MATERIALS AND METHODS: An analysis of 100 patients from the Brain-IT database was performed. Using the EUSIG definitions, 2,081 events can be obtained by analyzing the systolic and mean blood pressures on a minute by minute basis. A software program was written to identify and classify the trigger pattern for each event. A categorical analysis of these triggering patterns has been carried out. KEY RESULTS: Our analysis shows that most events are triggered by a drop in mean arterial pressure. In fact a large number of events (91%) occur where the mean arterial pressure is below the threshold limits whereas the systolic pressure does not cross the 90 mmHg limit at all. CONCLUSION: We suggest that more emphasis should be placed on closely monitoring mean arterial pressure as well as systolic pressure when trying to guard against hypotensive problems in traumatically brain injured patients. In future work we will study the underlying physiological mechanisms and attempt to further classify concomitant conditions that may be contributing to the onset of a hypotensive event.

Modulating effect of apolipoprotein E polymorphisms on secondary brain insult and outcome after childhood brain trauma.

OBJECTIVE: The aim of this study was to determine the relationship between apolipoprotein E (APO E) alleles, the amount of cerebral perfusion pressure (CPP) insult and outcome in children after brain trauma. MATERIALS AND METHODS: In a prospective two-centre case-control study, the APO E genotypes of 65 critically ill children admitted after brain trauma were correlated with age-related CPP insult quantification, conscious state at the time of discharge from intensive care and global outcome at 6 months post-injury. One hundred sixty healthy age- and sex-matched children were genotyped as controls. RESULTS: The CPP insult level among the e4 carriers with poor outcome was significantly less than the non-e4 carriers (p=0.03). Homozygotic e3 patients with good recovery did so despite having suffered nearly 26 times more CPP insult than those who were not e3 homzygous (p=0.02). CONCLUSION: Different APO E alleles may potentially affect cerebral ischaemic tolerance differently in children after brain trauma.

The use of hyperventilation therapy after traumatic brain injury in Europe: an analysis of the BrainIT database.

OBJECTIVE: To assess the use of hyperventilation and the adherence to Brain Trauma Foundation-Guidelines (BTF-G) after traumatic brain injury (TBI). SETTING: Twenty-two European centers are participating in the BrainIT initiative. DESIGN: Retrospective analysis of monitoring data. PATIENTS AND PARTICIPANTS: One hundred and fifty-one patients with a known time of trauma and at least one recorded arterial blood-gas (ABG) analysis. MEASUREMENTS AND RESULTS: A total number of 7,703 ABGs, representing 2,269 ventilation episodes (VE) were included in the analysis. Related minute-by-minute ICP data were taken from a 30 min time window around each ABG collection. Data are given as mean with standard deviation. (1) Patients without elevated intracranial pressure (ICP) (< 20 mmHg) manifested a statistically significant higher P(a)CO(2) (36 +/- 5.7 mmHg) in comparison to patients with elevated ICP (> or = 20 mmHg; P(a)CO(2): 34 +/- 5.4 mmHg, P < 0.001). (2) Intensified forced hyperventilation (P(a)CO(2) < or = 25 mmHg) in the absence of elevated ICP was found in only 49 VE (2%). (3) Early prophylactic hyperventilation (< 24 h after TBI; P(a)CO(2) < or = 35 mmHg, ICP < 20 mmHg) was used in 1,224 VE (54%). (4) During forced hyperventilation (P(a)CO(2) < or = 30 mmHg), simultaneous monitoring of brain tissue pO(2) or S(jv)O(2) was used in only 204 VE (9%). CONCLUSION: While overall adherence to current BTF-G seems to be the rule, its recommendations on early prophylactic hyperventilation as well as the use of additional cerebral oxygenation monitoring during forced hyperventilation are not followed in this sample of European TBI centers. DESCRIPTOR: Neurotrauma.

Low frequency pressure waves of possible autonomic origin in severely head-injured children.

BACKGROUND: Useful information (both clinical and pathophysiological) which may be extracted from intracranial pressure (ICP) recordings include: (1) the mean level of ICP (and CPP), (2) cerebrovascular autoregulation status, (3) the intracranial pulse pressure (the pulse wave index, ICPpp/ICPm) or the pressure-volume compensatory reserve index (RAP) and (4) the presence of any abnormal ICP waveform. This paper describes a slow frequency ICP waveform in children with TBI and postulates the pathophysiological basis and whether it contains clinically useful detail. METHODS: Children admitted to the Regional Head Injury Service in Edinburgh with TBI have continuously monitored ICP, MAP, CPP, and other physiological data (stored at a 1-min resolution). Slow frequency waveforms were noted, prompting a review of the stored monitoring from all cases over a 10 year period. FINDINGS: Episodic slow pressure waves were detected in 11 of 122 severely head-injured (HI) children. The waveforms were detected in children of all ages (1.6-15 years) in the ICP signal, which were in phase with similar fluctuations in the MAP, CPP, and HR signals. Their mean periodicity was 1 per 7 min (range 1 per 5-10 min), with a mean ICP pulse wave amplitude of 5.45 mmHg (range 4-7.5), and mean MAP pulse wave amplitude (pulse pressure) of 10.4 mmHg (range 4-15 mmHg). The duration was variable (range approx 2 h to 4.5 days). They were detected in the preterminal phase after serious HI, as well as in those children who made an independent recovery (GOS 4/5). The waves were not related to the mean levels of ICP, CPP, MAP, temperature or the state of cerebrovascular autoregulation. CONCLUSIONS: We postulate that these previously unreported slow waveforms may reflect the very low frequency (VLF) and ultra low frequency (ULF; < or = 1 per 5 min) components of heart rate and arterial blood pressure variability.

The measurement of brain tissue stiffness in-vivo.

BACKGROUND: There is considerable interest in surgical decompression as a management strategy (RescueICP) for intractable intracranial hypertension. After such an operation measurements of intracranial pressure (ICP) and thus cerebral perfusion pressure (CPP) become less meaningful. Measurements of the biomechanical properties of the brain may be one measure capable of detecting changing status of such patients. However these properties of the brain are neither documented or well understood. We have developed an indentation probe capable of making measurements of human brain stiffness. METHOD: The device consists of an indenting tip of depth 2 mm and diameter 12 mm surrounded by an annular body of 20 mm diameter. Measurements are made by two load cells, connected through interface electronics to a laptop computer. FINDINGS: Laboratory measurements show the probe to provide accurate and repeatable measurements over a range of zero to 10N. Inter-operator variability from six healthcare professionals had a coefficient of variance of 8.75%. Measurements obtained during surgery from a patient undergoing tumour resection were towards the lower end of the device's measurable range. CONCLUSIONS: We have determined that this indentation device has a linear response and that the inter- and intra-operator variability is low. Although the device is still in an early stage of development, preliminary results during intracranial surgery demonstrate that this device is capable of measuring in-vivo tissue stiffness. Further work is required to derive a quantitative "stiffness index" from the two load curves. In addition a standard operation method is required so that consistent and repeatable measurements are made. The device may be of value in assessing patients after decompressive craniectomy.

Are head injury guidelines changing the outcome of head injured children? A regional investigation.

BACKGROUND: Secondary pathophysiological CPP insult is related to outcome after head injury, and improved management would be expected to reduce secondary brain insult. Paediatric head injury management guidelines have been published in recent years, by SIGN (2000), RCPCH (2001), NICE (June 2003), and jointly by Critical/Intensive Care Societies (C/ICS July 2003). We investigated whether outcome of children's head injury (and total burden of secondary CPP insult) has changed (1) annually; (2) before and after the introduction of any HI guidelines, and (3) following other service changes. METHODS: Seventy-six children (aged 1-14 years with severe HI) were admitted to the Edinburgh Regional Head Injury Service between 1989 and 2006, and dichotomised at various time points and compared in terms of: demographic factors, intracranial pressure (ICP), cerebral perfusion pressure (CPP) insults [e.g. age-banded pressure-time index (PTI)], and Glasgow Outcome Scale (GOS) score (assessed at 6 months post injury). FINDINGS: When dichotomised around the SIGN guidelines, there were no statistically significant differences between the two group's demography or in primary brain injury, but the outcomes were different (p = 0.03), with 6 vs 4 GOS1 (died), 2 vs 4 GOS3 (severely disabled), 5 vs 16 GOS4 (moderately disabled) and 23 vs 14 GOS5 (good recovery), when comparing before and after year 2000. GOS4 was significantly different (chi-square = 7.99, p < 0.007). There was a (non-significant) trend for the later years to have longer insult durations of ICP, hypertension, CPP, hypoxia, pyrexia, tachycardia and bradycardia, greater PTI for both CPP and ICP, and more CPP insults (p = 0.003). There was, however, significantly less CPP insult (p = 0.030) after the introduction of the more management-oriented C/ICS guidelines. CONCLUSIONS: The most recent paediatric HI guidelines appear to have reduced the burden of secondary insult, but more time is required to determine if this will be reflected in improved outcomes.

Transcriptional up-regulation of the mouse cytosolic glutathione peroxidase gene in erythroid cells is due to a tissue-specific 3' enhancer containing functionally important CACC/GT motifs and binding sites for GATA and Ets transcription factors.

Nuclear run-on experiments have shown that the high level of expression of the mouse cytosolic glutathione peroxidase mRNA in erythroid cells is due to up-regulation of the gene at the transcriptional level. Studies of the chromatin structure around the cytosolic glutathione peroxidase gene have revealed a series of DNase I hypersensitive sites (DHSS) in the 3' flanking region of the gene in erythroid and other high-expression tissues that are lacking in low-expression cells, in addition to a DHSS over the promoter region in both high- and low-expression tissues. Functional transfection experiments have demonstrated that one of the 3' DHSS regions functions as an enhancer in erythroid cells but not in a low-expression epithelial cell line; and site-directed mutagenesis and footprinting experiments reveal that the activity of the erythroid cell-specific enhancer requires a cluster of binding sites for the CACC/GT box factors and the GATA and Ets families of transcription factors.

BrainIT: a trans-national head injury monitoring research network.

BACKGROUND: Studies of therapeutic interventions and management strategies on head injured patients are difficult to undertake. BrainIT provides validated data for analysis available to centers that contribute data to allow post-hoc analysis and hypothesis testing. METHODS: Both physiological and intensive care management data are collected. Patient identification is eliminated prior to transfer of data to a central database in Glasgow. Requests for missing/ ambiguous data are sent back to the local center. Country coordinating centers provide advice, training, and assistance to centers and manage the data validation process. RESULTS: Currently 30 centers participate in the group. Data collection started in January 2004 and 242 patients have been recruited. Data validation tools were developed to ensure data accuracy and all analysis must be undertaken on validated data. CONCLUSION: BrainIT is an open, collaborative network that has been established with primary objectives of i) creating a core data set of information, ii) standardizing the collection methodology, iii) providing data collection tools, iv) creating and populating a data base for future analysis, and v) establishing data validation methodologies. Improved standards for multi-center data collection should permit the more accurate analysis of monitoring and management studies in head injured patients.

Variability in pupil size estimation.

BACKGROUND: The clinical estimation of pupil size and reactivity is central to the neurological assessment of patients, particularly those with or at risk of neurological damage. Health care professionals who examine pupils have differing levels of skill and training, yet their recordings are passed along the patient care pathway and can influence care decisions. The aim of this study was to determine if any statistical differences existed in the estimation of pupil size by different groups of health care professionals. METHODS: A total of 102 health care professionals working in the critical care environment were asked to estimate and record the pupil size of a series of 12 artificial eyes with varying pupil diameter and iris colour. All estimations were performed indoors under ambient lighting conditions. RESULTS: Our results established a statistically significant difference between staff groups in the estimation of pupil size. CONCLUSION: The demonstrated variability in pupil size estimation may not be clinically significant. However, it remains desirable to have consistency of measurement throughout the patient care pathway.

In-house development of a dedicated data acquisition and monitoring system for intracranial pressure, patient posture and patient symptoms in a regional neurosciences centre.

Management of traumatic brain injury and cerebrospinal fluid (CSF) flow disorders can be aided by measurement and monitoring of intracranial pressure (ICP). In addition to pressure measurement, knowledge of patient symptoms and posture during monitoring are also valuable, particularly in the management of CSF flow disorders. ICP monitoring systems have been developed in this centre to meet clinical needs in the absence of commercially available solutions. An early system (mark I) was developed and the technical challenges in its design are described, along with limitations to this system that motivated the development of a new mark II system. The mark II system is then described.

Complementary tissue-specific expression of LIF and LIF-receptor mRNAs in early mouse embryogenesis.

The maintenance of pluripotential embryonic stem (ES) cells is dependent on the cytokine LIF. This report documents the mRNA expression profiles of LIF and the two components of the LIF-receptor complex, LIF-R and gp130, during early mouse embryogenesis. These mRNAs were undetectable in 1- or 2-cell embryos, but all were present by the blastocyst stage. LIF transcripts were localised in the differentiated trophectoderm, and were absent from the pluripotential inner cell mass. In contrast, LIF-R mRNA was found in the inner cell mass but not in the trophectoderm. This complementary pattern of expression is suggestive of a paracrine coupling between stem cells and differentiated progeny at the earliest stage of mammalian development. After implantation, transcripts for all components were down-regulated in the embryo. High levels of LIF-R and gp130 mRNAs were observed in the deciduum, however. These dynamic, tissue-specific expression patterns are consistent with regulatory roles for LIF or related cytokines, both in the maintenance of pluripotency in the mouse embryo, and in development of the foeto-maternal interface.

Maintenance of the pluripotential phenotype of embryonic stem cells through direct activation of gp130 signalling pathways.

Propagation of the undifferentiated pluripotential phenotype of embryonic stem (ES) cells is dependent on the cytokine differentiation inhibiting activity/leukemia inhibitory factor (DIA/LIF). The DIA/LIF receptor complex is a heterodimer of DIA/LIF receptor (DIA/LIF-R) and gp130. The latter is also a component of the interleukin-6 (IL-6) receptor complex. We report that a combination of IL-6 and soluble IL-6 receptor (sIL-6R), which can induce homodimerisation of gp130 and activation of signalling processes, sustains self-renewal of pluripotential ES cells. Our findings indicate that the IL-6/sIL-6R complex acts on ES cells through gp130 alone, bypassing DIA/LIF-R, and therefore implicate gp130 as the key component in the signalling pathway responsible for stem cell renewal.

Identification of genes regulated by leukemia-inhibitory factor in the mouse uterus at the time of implantation.

The endometrium is prepared for implantation by the actions of estradiol (E2) and progesterone (P4). In mice the luminal epithelium (LE) only becomes fully receptive to the attaching blastocyst in response to the nidatory estrogen surge on d 4 of pregnancy. The cytokine leukemia-inhibitory factor (LIF) is rapidly induced by nidatory estrogen and has been shown to be the primary mediator of its action. Implantation fails in the absence of LIF, and injection of LIF on d 4 of pregnancy can substitute for the nidatory estrogen. In this study, we sought to identify genes regulated by LIF in the uterine epithelium. We used oligonucleotide microarrays to compare the transcript profiles of paired uterine horns from LIF-deficient MF1 mice after intraluminal injection of LIF or PBS on d 4 of pseudopregnancy. IGF-binding protein 3 was identified as a gene up-regulated by LIF; this was confirmed by RT-PCR. In situ hybridization showed that the primary site of IGF-binding protein 3 expression is the luminal epithelium (LE), the known site of LIF action in the uterus. We identified two other genes: amphiregulin and immune response gene-1, the expression of which were also up-regulated by LIF. Immune response gene 1 has recently been shown to be essential for implantation. Expression of all three of these genes in the LE is known to be regulated by P4. The expression of osteoblast-specific factor 2 and leukocyte 12/15 lipoxygenase, which are also expressed in LE under the control of P4, were not increased by LIF. This suggests that one of the actions of LIF on LE may be to enhance the expression of a subset of P4-regulated genes.

Clinical comparison of tympanic membrane displacement with invasive ICP measurements.

OBJECTIVE: Tympanic membrane displacement (TMD) measurements may be useful in the management of patients with hydrocephalus if they can be directly associated with measurements of ICP. We have compared TMD measurements using the Marchbanks Measurement System with invasive ICP monitoring. METHODS: Twenty-nine patients who were undergoing routine invasive monitoring using a Camino fibre optic ICP measurement system as part of their clinical management were studied. Simultaneous measurements of ICP and TMD in both sitting and supine positions were successfully made in thirteen patients. RESULTS: Thirty-nine pairs of readings were obtained. The invasive ICP readings varied from 1 to 36 mmHg in the supine position and from -12 to +35 mmHg sitting. Corresponding TMD values varied from 275 to +277 nL in the supine position and -133 to +466 nL sitting. Linear regression showed a significant negative relationship between the two measurements (r = -0.57, p = 0.0013). CONCLUSIONS: There is a strong negative linear association between mean TMD and invasively measured ICP and this relationship is highly significant. Nevertheless, TMD is a poor surrogate for ICP in clinical terms because the predictive limits of the linear regression are too wide. However, serial intra-patient measurements may be useful to determine changes in ICP with time.

Which paediatric head injured patients might benefit from decompression? Thresholds of ICP and CPP in the first six hours.

Severe head injury in childhood continues to be associated with considerable mortality and morbidity. Early surgical decompression may be beneficial and the objective of this study was to examine the relationship between age-related thresholds of mean intracranial pressure (ICP) and cerebral perfusion pressure (CPP) over the first 6 hours and age outcome in paediatric head injury patients. A total of 209 head injured children admitted to five UK hospitals were studied. Patients aged 2 to 16 years were included if they had a minimum of six hours of invasive pressure monitoring. Mean values of ICP and CPP over this period were calculated and compared to those with independent (good recovery and moderate disability) and poor outcome (severe disability, and death) for different age groups. There were 148 children with independent outcome (92 good recovery, 56 moderately disabled), and 61 with poor outcome (30 severely disabled, 31 deaths). There was a significant difference between those with independent compared to poor outcome in relation to ICP (p < 0.001) and CPP (p < 0.001). Patients were divided into three groups according to age. The sensitivity of ICP and CPP in predicting outcome was similar for all groups but the specificity differed between groups. At a CPP of 50 mmHg the specificity varied between the age groups (2 to 6 years: 0.47, 7 to 10 years: 0.28 and 11 to 16 years: 0.10) and similarly for an ICP of 25 mmHg (2 to 6 years: 0.53, 7 to 10 years: 0.44 and 11 to 16 years: 0.38). Younger children may be able to tolerate lower perfusion pressures and still have an independent outcome. Our threshold values for young children are likely to be important in the identification of patients who might benefit from new treatments such as surgical decompression.

The BrainIT Group: concept and current status 2004.

INTRODUCTION: An open collaborative international network has been established which aims to improve inter-centre standards for collection of high-resolution, neurointensive care data on patients with traumatic brain injury. The group is also working towards the creation of an open access, detailed and validated database that will be useful for hypothesis generation. In Part A, we describe the underlying concept of the group and it's aims and in Part B we describe the current status of the groups development. METHODS: Four group meetings funded by the EEC have enabled definition of a "Core Dataset" to be collected from all centres regardless of specific project aim. A form based feasibility study was conducted and a prospective data collection exercise of core data using PC and hand held computer based methods is in progress. FINDINGS: A core-dataset was defined and can be downloaded from the BrainIT web-site (go to "Core dataset" link at: www.brainit.org). A form based feasibility study was conducted showing the overall feasibility for collection of the core data elements was high. Software tools for collection of the core dataset have been developed. Currently, 130 patient's data from 16 European centres have been recruited to the joint database as part of an EEC funded proof of concept study. INTERPRETATION: The BrainIT network provides a more standardised and higher resolution data collection mechanism for research groups, organisations and the device industry to conduct multicentre trials of new health care technology in patients with traumatic brain injury.

Accurate data collection for head injury monitoring studies: a data validation methodology.

BACKGROUND: BrainIT is a multi centre, European project, to collect high quality continuous data from severely head injured patients using a previously defined [6] core data set. This includes minute-by-minute physiological data and simultaneous treatment and management information. It is crucial that the data is correctly collected and validated. METHODS: Minute-by-minute physiological monitoring data is collected from the bedside monitors. Demographic and clinical information, intensive care management and secondary insult management data, are collected using a handheld computer. Data is transferred from the handheld device to a local computer where it is reviewed and anonymised before being sent electronically, with the physiological data, to the central database in Glasgow. Automated computer tools highlight missing or ambiguous data. A request is then sent to the contributing centre where the data is amended and returned to Glasgow. Of the required data elements 20% are randomly selected for validation against original documentation along with the actual number of specific episodic events during a known period. This will determine accuracy and the percentage of missing data for each record. CONCLUSION: Advances in patient care require an improved evidence base. For accurate, consistent and repeatable data collection, robust mechanisms are required which should enhance the reliability of clinical trials, assessment of management protocols and equipment evaluations.

Survey of traumatic brain injury management in European Brain-IT centres year 2001.

BACKGROUND: The aim of this study was to obtain basic knowledge about the current local conditions and neurointensive care of traumatic brain injury (TBI) in the new multi-centre collaborative BrainIT group. MATERIALS AND METHODS: The survey comprised a background part on local policies (Part A), and a case study section (Part B). The information was gathered by questionnaire followed by telephone interviews. Twenty-three BrainIT centres participated in the survey and answers from two respondents were available from 18 of the sites. RESULTS: The average proportion of agreement between duplicate respondents was 0.778 (range 0.415-1.00). All BrainIT centres monitored ICP. The treatment protocols seem to have a pattern concerning escalation of treatment of intracranial hypertension: 1/ evacuation of mass lesions and head elevation; 2/ increased sedation and mannitol; 3/ hyperventilation; 4/ ventricular drainage; 5/ craniectomy and barbituates. CONCLUSIONS: There seemed to be an agreement on neurointensive care policies within the BrainIT group. The suggested order of treatment was generally in accordance with published guidelines although the suggested order and combinations of different treatments varied. Variation of treatment within the range of prescribed standards provides optimal conditions for an interesting future analysis of treatment and monitoring data in reality using the BrainIT database.