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Objective: To determine the statistical characteristics of blood pressure (BP) readings from a large number of head-injured patients.Methods: The BrainIT group has collected high time-resolution physiological and clinical data from head-injured patients who require intracranial pressure (ICP) monitoring. The statistical features of this dataset of BP measurements with time resolution of 1 min from 200 patients is examined. The distributions of BP measurements and their relationship with simultaneous ICP measurements are described.Results: The distributions of mean, systolic and diastolic readings are close to normal with modest skewing towards higher values. There is a trend towards an increase in blood pressure with advancing age, but this is not significant. Simultaneous blood pressure and ICP values suggest a triphasic relationship with a BP rising at 0.28 mm Hg/mm Hg of ICP, for ICP up to 32 mm Hg, and 0.9 mm Hg/mm Hg of ICP for ICP from 33 to 55 mm Hg, and falling sharply with rising ICP for ICP >55 mm Hg.Conclusions: Patients with head injury appear to have a near normal distribution of blood pressure readings that are skewed towards higher values. The relationship between BP and ICP may be triphasic. [ABSTRACT FROM AUTHOR]

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.

Introduction: Medical case notes are the only lasting interpretation of a patient-physician interaction and are important for good quality patient care. Accurate, legible and contemporaneous note-keeping is important however it can be substandard. This can lead to errors in handover of patients and to medicolegal vulnerability. We present a comprehensive auditing tool for Trauma & Orthopaedics medical case notes and our experience in using it over the last 12 months., Patients and Methods: The TONK score was developed from a pre-existing system with some additions for Trauma & Orthopaedic case notes, with the incorporation of a legibility scoring system. An initial audit was carried out evaluating the case notes for each team against the TONK score. In order to evaluate the reproducibility of this score, we employed the Cohen's Kappa coefficient and noted substantial agreement. The individual team scores were analysed and the audit cycle completed four months later with the provision of feedback., Results: Our first audit revealed a mean of 81 with a range from 70 to 90. Subsequent audits over the next two quarters revealed mean scores in excess of 90. Significant improvement has been noted in all areas of documentation and it has been decided to conduct this audit every six months in our department., Conclusions: The TONK score is an easy, quick and reproducible tool, which aims to eliminate the weaknesses in Trauma & Orthopaedic medical note-keeping. It emphasises the medicolegal importance of accurate medical note-keeping to doctors at all levels of training.

Background: While it is accepted practice to remove extradural (EDH) and subdural haematomas (SDH) following traumatic brain injury, the role of surgery in parenchymal traumatic intracerebral haemorrhage (TICH) is controversial. There is no evidence to support Early Surgery in this condition., Objectives: There have been a number of trials investigating surgery for spontaneous intracerebral haemorrhage but none for TICH. This study aimed to establish whether or not a policy of Early Surgery for TICH improves outcome compared with a policy of Initial Conservative Treatment., Design: This was an international multicentre pragmatic parallel group trial. Patients were randomised via an independent telephone/web-based randomisation service., Setting: Neurosurgical units in 59 hospitals in 20 countries registered to take part in the study., Participants: The study planned to recruit 840 adult patients. Patients had to be within 48 hours of head injury with no more than two intracerebral haematomas greater than 10 ml. They did not have a SDH or EDH that required evacuation or any severe comorbidity that would mean they could not achieve a favourable outcome if they made a complete recovery from their head injury., Interventions: Patients were randomised to Early Surgery within 12 hours or to Initial Conservative Treatment with delayed evacuation if it became clinically appropriate., Main Outcome Measures: The Extended Glasgow Outcome Scale (GOSE) was measured at 6 months via a postal questionnaire. The primary outcome was the traditional dichotomised split into favourable outcome (good recovery or moderate disability) and unfavourable outcome (severe disability, vegetative, dead). Secondary outcomes included mortality and an ordinal assessment of Glasgow Outcome Scale and Rankin Scale., Results: Patient recruitment began in December 2009 but was halted by the funding body because of low UK recruitment in September 2012. In total, 170 patients were randomised from 31 centres in 13 countries: 83 to Early Surgery and 87 to Initial Conservative Treatment. Six-month outcomes were obtained for 99% of 168 eligible patients (82 Early Surgery and 85 Initial Conservative Treatment patients). Patients in the Early Surgery group were 10.5% more likely to have a favourable outcome (absolute benefit), but this difference did not quite reach statistical significance because of the reduced sample size. Fifty-two (63%) had a favourable outcome with Early Surgery, compared with 45 (53%) with Initial Conservative Treatment [odds ratio 0.65; 95% confidence interval (CI) 0.35 to 1.21; p = 0.17]. Mortality was significantly higher in the Initial Conservative Treatment group (33% vs. 15%; absolute difference 18.3%; 95% CI 5.7% to 30.9%; p = 0.006). The Rankin Scale and GOSE were significantly improved with Early Surgery using a trend analysis (p = 0.047 and p = 0.043 respectively)., Conclusions: This is the first ever trial of surgery for TICH and indicates that Early Surgery may be a valuable tool in the treatment of TICH, especially if the Glasgow Coma Score is between 9 and 12, as was also found in Surgical Trial In spontaneous intraCerebral Haemorrhage (STICH) and Surgical Trial In spontaneous lobar intraCerebral Haemorrhage (STICH II). Further research is clearly warranted., Trial Registration: Current Controlled Trials ISRCTN 19321911., Funding: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 19, No. 70. See the NIHR Journals Library website for further project information.

Intraparenchymal hemorrhages occur in a proportion of severe traumatic brain injury TBI patients, but the role of surgery in their treatment is unclear. This international multi-center, patient-randomized, parallel-group trial compared early surgery (hematoma evacuation within 12 h of randomization) with initial conservative treatment (subsequent evacuation allowed if deemed necessary). Patients were randomized using an independent randomization service within 48 h of TBI. Patients were eligible if they had no more than two intraparenchymal hemorrhages of 10 mL or more and did not have an extradural or subdural hematoma that required surgery. The primary outcome measure was the traditional dichotomous split of the Glasgow Outcome Scale obtained by postal questionnaires sent directly to patients at 6 months. The trial was halted early by the UK funding agency (NIHR HTA) for failure to recruit sufficient patients from the UK (trial registration: ISRCTN19321911). A total of 170 patients were randomized from 31 of 59 registered centers worldwide. Of 82 patients randomized to early surgery with complete follow-up, 30 (37%) had an unfavorable outcome. Of 85 patients randomized to initial conservative treatment with complete follow-up, 40 (47%) had an unfavorable outcome (odds ratio, 0.65; 95% confidence interval, CI 0.35, 1.21; p=0.17), with an absolute benefit of 10.5% (CI, -4.4-25.3%). There were significantly more deaths in the first 6 months in the initial conservative treatment group (33% vs. 15%; p=0.006). The 10.5% absolute benefit with early surgery was consistent with the initial power calculation. However, with the low sample size resulting from the premature termination, we cannot exclude the possibility that this could be a chance finding. A further trial is required urgently to assess whether this encouraging signal can be confirmed.

Training staff in the resuscitation of neonates is an essential skill; resuscitation efficacy is difficult to quantify but critical to infant survival. Objective assessments of the efficacy of training methods, resuscitation techniques and devices have used concurrent measurements of air flow and air pressure in commercially available manikins. This system also simultaneously measures the force transmitted through the manikin head during simulated resuscitation, as applying excessive force may be deleterious to newborn infants. The overall accuracy of the force plate over the range 0-5 kg was 0.5%; the output was linear; the frequency response sufficiently high and there was no evidence of hysteresis. This system enables comparison of staff groups, resuscitation techniques and devices in an accurate and reproducible manner. Its use could improve training by offering a means of objective performance feedback through a range of parameters. Evaluation of clinical practice may also result in direct patient benefit.

Background: Intracranial hemorrhage occurs in over 60% of severe head injuries in one of three types: extradural (EDH); subdural (SDH); and intraparenchymal (TICH). Prompt surgical removal of significant SDH and EDH is established and widely accepted. However, TICH is more common and is found in more than 40% of severe head injuries. It is associated with a worse outcome but the role for surgical removal remains undefined. Surgical practice in the treatment of TICHs differs widely around the world. The aim of early surgery in TICH removal is to prevent secondary brain injury. There have been trials of surgery for spontaneous ICH (including the STICH II trial), but none so far of surgery for TICH., Methods/design: The UK National Institutes of Health Research has funded STITCH(Trauma) to determine whether a policy of early surgery in patients with TICH improves outcome compared to a policy of initial conservative treatment. It will include a health economics component and carry out a subgroup analysis of patients undergoing invasive monitoring. This is an international multicenter pragmatic randomized controlled trial.Patients are eligible if: they are within 48 h of injury; they have evidence of TICH on CT scan with a confluent volume of attenuation significantly raised above that of the background white and grey matter that has a total volume >10 mL; and their treating neurosurgeon is in equipoise.Patients will be ineligible if they have: a significant surface hematoma (EDH or SDH) requiring surgery; a hemorrhage/contusion located in the cerebellum; three or more separate hematomas fulfilling inclusion criteria; or severe pre-existing physical or mental disability or severe co-morbidity which would lead to poor outcome even if the patient made a full recovery from the head injury.Patients will be randomized via an independent service. Patients randomized to surgery receive surgery within 12 h. Both groups will be monitored according to standard neurosurgical practice. All patients have a CT scan at 5 days (+/-2 days) to assess changes in hematoma size. Follow-up is by postal questionnaire at 6 and 12 months. The recruitment target is 840 patients., Trial Registration: Current Controlled Trials ISRCTN19321911.

Introduction: Femoral neck fractures are an increasingly common injury in the elderly. Frequently these patients present taking Clopidogrel, an irreversible inhibitor of platelet aggregation. Although this is associated with an increased risk of intra-operative bleeding and also an increased risk of spinal haematoma where regional anaesthesia is employed, the recent SIGN (Scottish Intercollegiate Guidance Network) guidelines recommend that surgery should not be delayed., Methods: We conducted a retrospective review of consecutive patients admitted with femoral neck fractures between April 2008 and October 2009. Patients on Clopidogrel were identified and data including ASA grade, time to operation, medical co-morbidities, and post-admission complications were recorded. Comparative information from the National Hip Fracture Database was used., Results: 405 patients were included. 27 patients were taking Clopidogrel on admission and they were all ASA 3 or 4. Mean time to theatre was 8 days. Post-admission medical complications occurred in 7 patients (25.9%). A further 4 patients (14.8%) died, 3 of them post-operatively. From the study population a control group of 72 ASA 3 and 4 patients was further studied. The mean time to operation was 2.3 days. Post-admission medical complications occurred in 13 patients (18%) and 8 patients (11%) died post-operatively. The difference in the mortality and morbidity of these two groups was found to be statistically not significant. In 2009 the national mean time to operation was 2.19 days with an associated mortality rate of 8.67%., Discussion and Conclusion: Patients receiving Clopidogrel have complex medical co-morbidities and a higher anaesthetic risk. Delaying operative management might be contributing to the increased rate of mortality and morbidity. In accordance with the SIGN guidelines we recommend early operative intervention in these high risk patients., (Copyright © 2010 Royal College of Surgeons of Edinburgh (Scottish charity number SC005317) and Royal College of Surgeons in Ireland. Published by Elsevier Ltd. All rights reserved.)

Adaptive immunity is an important component to clearance of intracellular pathogens. The ability to detect and quantify these responses in humans is an important diagnostic tool. The enzyme-linked immunospot assay (ELISPOT) is gaining popularity for its ability to identify cellular immune responses against microbial antigens, including immunosuppressed populations such as those with HIV infection, transplantation, and steroid use. This assay has the capacity to quantify the immune responses against specific microbial antigens, as well as distinguish if these responses are Th1 or Th2 in character. ELISPOT is not limited to the site of inflammation. It is versatile in its ability to assess for immune responses within peripheral blood, as well as sites of active involvement such as bronchoalveolar lavage, cerebral spinal fluid, and ascites. Detection of immune responses against a single or multiple antigens is possible, as well as specific epitopes within microbial proteins. This assay facilitates detection of immune responses over time, as well as distinctions in antigens recognized by host T cells. Dual color ELISPOT assays are available for detection of simultaneous expression of two cytokines. Recent applications for this technique include diagnosis of extrapulmonary tuberculosis, as well as investigation of the contribution of infectious antigens to autoimmune diseases.

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.

Objective: The aim of this study was to evaluate the robustness and zero-drift of an intracranial pressure sensor, Neurovent-P (Raumedic AG, Münchberg, Germany), when used in the clinical environment., Methods: A prospective multicenter trial, conforming to the International Organization for Standardization 14155 Standard, was conducted in 6 European BrainIT centers between July 2005 and December 2006. Ninety-nine catheters were used. The study was observational, followed by a centralized sensor bench test after catheter removal., Results: The mean recorded value before probe insertion was 0.17 +/- 1.1 mm Hg. Readings outside the range +/-1 mm Hg were recorded in only 3 centers on a total of 15 catheters. Complications were minimal and mainly related to the insertion bolt. The mean recorded pressure value at removal was 0.8 +/- 2.2 mm Hg. No relationship was identified between postremoval reading and length of monitoring. The postremoval bench test indicated the probability of a system failure, defined as a drift of more than 3 mm Hg, at a range between 12 and 17%., Conclusion: The Neurovent-P catheter performed well in clinical use in terms of robustness. The majority of technical complications were associated with the bolt fixation technology. Adverse events were rare and clinically nonsignificant. Despite the earlier reported excellent bench test zero-drift rates, under the more demanding clinical conditions, zero-drift rate remains a concern with catheter tip strain gauge technology. This performance is similar, and not superior, to other intracranial pressure devices.

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.

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.

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.

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.

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.

Background: The principal strategy for managing head injury is to reduce the frequency and severity of secondary brain insults from intracranial pressure (ICP) and cerebral perfusion pressure (CPP), and hence improve outcome. Precise critical threshold levels have not been determined in head injured children., Objective: To create a novel pressure-time index (PTI) measuring both duration and amplitude of insult, and then employ it to determine critical insult thresholds of ICP and CPP in children., Methods: Prospective, observational, physiologically based study from Edinburgh and Newcastle, using patient monitored blood pressure, ICP, and CPP time series data. The PTI for ICP and CPP for 81 children, using theoretical values derived from physiological norms, was varied systematically to derive critical insult thresholds which delineate Glasgow outcome scale categories., Results: The PTI for CPP had a very high predictive value for outcome (receiver operating characteristic analyses: area under curve = 0.957 and 0.890 for mortality and favourable outcome, respectively) and was more predictive than for ICP. Initial physiological values most accurately predicted favourable outcome. The CPP critical threshold values determined for children aged 2-6, 7-10, and 11-15 years were 48, 54, and 58 mm Hg. respectively., Conclusions: The PTI is the first substantive paediatric index of total ICP and CPP following head injury. The insult thresholds generated are identical to age related physiological values. Management guidelines for paediatric head injuries should take account of these CPP thresholds to titrate appropriate pressor therapy.

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.

A non-invasive method of assessing intracranial pressure (ICP) would be of benefit to patients with abnormal cerebral pathology that could give rise to changes in ICP. In particular, it would assist the regular monitoring of hydrocephalus patients. This study evaluated a technique using tympanic membrane displacement (TMD) measurements, which has been reported to provide a reliable, non-invasive measure of ICP. A group of 135 hydrocephalus patients was studied, as well as 13 patients with benign intracranial hypertension and a control group of 77 volunteers. TMD measurements were carried out using the Marchbanks measurement system analyser and compared between the groups. In 36 patients, invasive measurements of ICP carried out at the same time were compared with the TMD values. A highly significant relationship was found between TMD and ICP but intersubject variability was high and the predictive value of the technique low. Taking the normal range of ICP to be 10-15 mmHg, the predictive limits of the regression are an order of magnitude wider than this and therefore Vm cannot be used as a surrogate for ICP. In conclusion, TMD measurements do not provide a reliable non-invasive measure of ICP in patients with shunted hydrocephalus.

Objectives: Severe head injury in childhood is associated with considerable mortality and morbidity. In this study we determined age-related differences in the relationship between outcome and intracranial pressure (ICP) and cerebral perfusion pressure (CPP) in the first 6 h of monitoring in a large cohort of head-injured children., Methods: Two hundred and thirty-five head-injured children (admitted to five UK hospitals over a 15-year period) in whom intracranial pressure monitoring was clinically indicated were studied., Results: Patients were divided into three age groups (2-6, 7-10 and 11-16 years). The sensitivity of ICP and CPP were similar. Differences were found in the specificity of ICP and CPP for each group and these were more marked for CPP. For a specificity of 50% the pressures were 53, 63 and 66 mmHg for the three age groups., Conclusions: There are age-related differences in the specificity of intracranial pressure and cerebral perfusion pressure in relation to outcome. These differences may be important in the clinical management of head-injured children. Thus cerebral perfusion pressures of 53, 63 and 66 mmHg should be the minimum to strive for in these three age groups respectively.

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.

This paper describes and validates a new Cumulative Pressure-Time Index (CPT) which takes into account both duration and degree of cerebral perfusion pressure (CPP) derangement and determines critical thresholds for CPP, in a paediatric head injury dataset. Sixty-six head-injured children, with invasive minute-to-minute intracranial pressure (ICP) and blood pressure monitoring, had their pre-set CPP derangement episodes (outside the normal range) identified in three childhood age-bands (2-6, 7-10, and 11-16 years) and global outcome assessed at six months post injury. The new cumulative pressure-time index more accurately predicted outcome than previously used summary measures and by varying the threshold CPP values, it was found that these physiological threshold values (< or = 48, < or = 52 and < or = 56 mmHg for 2-6, 7-10, and 11-16 years respectively) best predicted brain insult in terms of subsequent mortality and morbidity.

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.

Head injury is a major cause of death and disability in children. Despite advances in resuscitation, emergency care, intensive care monitoring, and clinical practices, there are few data demonstrating the predictive value of certain physiological variables regarding outcome in this patient population. Mean arterial blood pressure (MABP), intracranial pressure (ICP), and cerebral perfusion pressure (CPP = MABP - ICP) are routinely monitored in patients in many neurological intensive care units throughout the world, but there is little evidence indicating that advances in care have been matched with corresponding improvements in outcome. Nonetheless, there is evidence that hypotension immediately following head injury is predictive of early death, and many patients with these features die with clinical signs of brain herniation caused by intracranial hypertension. Furthermore, available data indicate that a minimal and a mean CPP measured during intensive care are good predictors of outcome in survivors, but a target threshold to improve outcome has yet to be defined. Some medical management strategies can have detrimental effects, and there is now a good case for undertaking a controlled trial of immediate or delayed craniectomy. Independent outcome in children following severe head injury is associated with higher levels of CPP. The ability to tolerate different levels of CPP may be related to age, and therefore any such surgical trial would need a carefully defined protocol so that the potential benefit of such a treatment is maximized.

The Spiegelberg brain pressure catheter is a low cost implantable intracranial pressure measuring system which has the unique ability to perform regular automatic zeroing. A new version of the catheter has become available with a subdural bolt fixation to allow insertion of the device into the brain parenchyma. The accuracy of this system has been evaluated in comparison with a ventricular fluid pressure method in a series of patients to determine its accuracy and utility in the clinical environment. Hourly readings from the Spiegelberg system have been compared with those obtained using a standard pressure transducer connected to an external ventricular drain. Measurements continued while there was a clinical need for CSF drainage. Eleven patients were recruited to the study and data were recorded for periods ranging from 40 to 111 hours. A good agreement between the two systems was obtained. In 10 cases the mean difference was less than +/-1.5 mm Hg and the dynamic changes in value were contemporaneous. In one case an intracerebral haemorrhage developed around the tips of the Spiegelberg catheter and significant differences occurred between the two methods of measurement. In conclusion, the Spiegelberg parenchymal transducer provides an accurate measurement of intracranial pressure when compared with ventricular pressure. The transducer was found to be robust in the clinical environment and very popular with the nursing staff. Further studies may determine whether the complication rate of this system is comparable with other available devices.

The radiological features of the cement mantle around total hip replacements (THRs) have been used to assess aseptic loosening. In this case-control study we investigated the risk of failure of THR as predictable by a range of such features using data from patients recruited to the Trent Regional Arthroplasty Study (TRAS). An independent radiological assessment was undertaken on Charnley THRs with aseptic loosening within five years of surgery and on a control group from the TRAS database. Chi-squared tests were used to test the probability of obtaining the observed data by chance, and odds ratios were calculated to estimate the strength of association for different features. Several features were associated with a clinically important increase (>twofold) in the risk of loosening, which was statistically significant for four features (p < 0.01). Inadequate cementation (Barrack C and D grades) was the most significant feature, with an estimated odds ratio of 9.5 (95% confidence interval 3.2 to 28.4, p < 0.0001) for failure.

We report the time course of intracranial pressure within a developing intracerebral haemorrhage. Simultaneous readings of intracranial pressure were obtained from a contralateral parenchymal monitor and ventricular fluid pressure monitor. This recording demonstrates the existence of large pressure gradients in patients with expanding mass lesions.

Object: Intracranial pressure (ICP) and cerebral perfusion pressure (CPP) are frequently monitored in severely head injured patients. To establish which one (ICP or CPP) is more predictive of outcome and to examine whether there are significant threshold levels in the determination of outcome, receiver-operating characteristic (ROC) curves were used to analyze data in a large series of head-injured patients., Methods: Data were obtained from a total of 291 severely head injured patients (207 adults and 84 children). Outcome was categorized as either independent (good recovery or moderate disability) or poor (severely disabled, vegetative, or dead) by using the Glasgow Outcome Scale; patients were also grouped according to the Marshall computerized tomography scan classification., Conclusions: The maximum value of a 2-minute rolling average of ICP readings (defined as ICPmax) and the minimum value of the CPP readings (CPPmin) were then used to calculate the sensitivity and specificity of the ROC curves over a range of values. Using ROC curves, a threshold value for CPPmin of 55 mm Hg and for ICPmax of 35 mm Hg appear to be the best predictors in adults. For children the levels appear to be 43 to 45 mm Hg for CPPmin and 35 mm Hg for ICPmax. Higher levels of CPPmin seem important in adults with mass lesions. These CPP thresholds (45 mm Hg for children and 55 mm Hg for adults) are lower than previously predicted and may be clinically important, especially in children, in whom a lower blood pressure level is normal. Also, CPP management at higher levels may be more important in adults with mass lesions. A larger observational series would improve the accuracy of these predictions.

The aim of this study was to determine the in vivo accuracy and reliability of intracranial pressure (ICP) measurement using the Codman MicroSensor by comparison with the Camino ICP transducer and associated clinical and radiological information. Paired ICP readings were recorded every minute in 17 patients. A total of 56,790 validated paired measurements were obtained over a wide range of ICP values (- 16 mm Hg to 114 mm Hg). Recording periods ranged from 3 hours to 6 days (median 41 hours). In 11 patients the MicroSensor and Camino readings were in good agreement. Paired readings were within 10 mmHg for 99% of the recording time and both readings were compatible with clinical intracranial events at all times (in one case it was not possible to verify the clinical information). In six patients large differences occurred between transducer readings (> 10 mm Hg apart for 41% of the recording period). In one case, either reading could have been compatible with intracranial clinical events. In two cases, although both readings were comparable, Camino readings were more consistent with clinical and radiological findings. In three cases, the MicroSensor readings were inconsistent with the clinical condition of the patients whereas the Camino readings were compatible. These results suggest that, during routine clinical use in our department, the MicroSensor provided misleading information in 18% of our patients and thus is not sufficiently reliable for routine use in the detection of adverse clinical events.

The cause and incidence of reductions in cerebral perfusion pressure, and rises in intracranial pressure have been examined in a series of patients with severe head injury defined as an initial Glasgow Coma Sum of less than or equal to 8. Two-hundred-and-seven adults (aged over 16 years) and 84 children admitted to Newcastle General Hospital, who had intracranial pressure monitoring as part of their routine management, were studied. Intracranial pressure (ICP), arterial pressure and cerebral perfusion pressure (CPP) were sampled and recorded every 2 min. Patients' CT findings were classified into distinct groups using the method described by Marshall. Secondary insults were defined using the Edinburgh University Secondary Insult Grades (EUSIG) and the incidence and cause (raised ICP, reduced CPP or a combination of the two) was established. Outcome was assessed at 6 months using the Glasgow Outcome Scale. In the majority of adults with head injury it is the combination of reduced arterial pressure and raised ICP that contributes to the reduction in cerebral perfusion pressure. This was not the case for Diffuse Injury Type I. In children similar characteristics were found across each of the CT classifications. The vast majority of falls in CPP down to 60 mmHg were caused by reduced arterial pressure. Reductions below 50 mmHg were almost always due to a combination of both reduced arterial pressure and raised ICP. The results in adults were similar, but not identical, to those of the paediatric cases. Diffuse Injury Type I stood out from all the other categories as the only one where reductions in perfusion pressure were almost exclusively due to reductions in arterial pressure and not to increases in ICP. The management of these patients should ensure the adequacy of perfusion pressure by maintaining arterial pressure at a satisfactory level. These results suggest that vigilant monitoring of both intracranial pressure and arterial pressure is required to lower the incidence of secondary insults.

Introduction: The use of the Camino fibre-optic subdural device for measuring Intracranial Pressure (ICP) in patients, has been shown to correlate well with recordings from the "gold standard" intraventricular fluid filled catheter [1]. Following this work, its use has become standard in the clinical monitoring of patients. More recently, laboratory studies have demonstrated accuracy, acceptable drift and high fidelity for the new Codman Microsensor ICP Transducer, a miniature strain gauge mounted on a flexible nylon catheter [3]. Its performance in patients, however, has yet to be fully assessed, in comparative studies., Methods: Eight patients (5 head injured, 3 with an Intracerebral haematoma) had a Codman Microsensor inserted. A Camino Transducer was fitted immediately adjacent to it. A computerised system was used to continuously record both ICP readings., Results: In total 140,323 recordings were made over a wide range of ICP values. Study periods ranged from 0.5 to 116 hours. In one patient the Codman transducer tracing failed after several days, probably due to fracture of electrical cable close to the interface box. The readings from the two ICP transducers were compared on Time Series, logistic regression and Altman-Bland plots. Drift of the ICP recorded by the Codman microsensor, was noted in 2 patients, 1 in positive direction (maximum 30 mmHg), 1 negative (max. 20 mmHg). In both cases the Camino ICP recording was relatively stable. In 24% of the recordings the Codman microsensor recorded ICP as 5 or more mmHg greater than the Camino, this difference was 10 mmHg or greater in 9% of recordings. Conversely the Camino recording was 5 mmHg or more, than the Codman, in 5% of all recordings, and 10 mmHg or more in 3%., Conclusion: These differences could in the majority of cases (excepting the negative drift) be explained by a constant offset of the Codman transducer, as described previously [6]. Further examination of this device is required.

The aim of head injury management is to prevent secondary insults to the damaged brain. Raised intracranial pressure and low cerebral perfusion pressure are two secondary insults which are important determinants of outcome following severe head injury (SHI). Traditionally ICP is measured in the right frontal region in an attempt to minimise the effects and complications of transducer placement. This assumes that the brain acts like a fluid and that ICP is transmitted equally throughout the intracranial space. Experimental studies suggest that this is not the case: expanding mass lesions are associated with the development of ICP gradients. Ten patients with SHI who had an unilateral mass lesion confirmed on CT were studied. All had bilateral placement of intraparenchymal Camino ICP transducers in the frontal regions. Data from both transducers were recorded every two minutes and stored electronically. The volume of the mass lesion was calculated from the CT scan. Significant and lasting ICP gradients between hemispheres were found in all patients with an acute subdural haematoma (greater than 10 mmHg for longer than 10 minutes). Such differences were not found in patients with intracerebral haematoma or contusions. We would advocate that ICP is recorded IPSILATERAL to the lesion in patients with SHI due to acute subdural haematoma.

Background and Purpose: Experimental stroke research has for the most part incorporated the use of young animals despite the importance of aging in cerebrovascular disease in humans. We hypothesized that age-related reductions in the density and function of cortical N-methyl-D-aspartate (NMDA) receptors might limit neuroprotective potential in the elderly. In this study, a model of occlusive stroke in the aging rat brain has been developed and used to establish the effects of age on cerebral infarction and to evaluate the scope for protecting the aging brain during ischemia., Methods: Focal cerebral ischemia was produced by thermocoagulation of the left middle cerebral artery in adult (11 to 17 months) and aged (28 to 36 months) male Wistar rats. Infarcts were assessed histologically with volumetric analysis of infarct size, hemodynamically by serial cerebral blood flow measurement using the hydrogen clearance technique, and by analysis of specific gravity as an index of brain edema. Neuroprotective potential was assessed using the competitive NMDA receptor antagonist 3-(2-carboxy piperazin-4-yl)propyl-1-phosphonate (D-CPPene)., Results: Aging was associated with a significant increase in infarct size, with a mean infarct volume of 40.5 +/- 2.6% of the hemisphere volume in aged rats compared with 30.9 +/- 0.7% in adult rats (P < .01). D-CPPene reduced the mean infarct volume to 33 +/- 1.8% and 20.7 +/- 3.2% in aged and adult rats, respectively (P < .05). Cerebral blood flow fell markedly after infarction, but thereafter D-CPPene-pretreated rats maintained higher cerebral blood flow than untreated animals throughout the duration of the experiment (22.8 +/- 3.2 and 30.1 +/- 5.5 mL.100 g-1.min-1 in treated aged and adult rats, respectively, compared with 11.3 +/- 2.7 and 16.5 +/- 3.2 mL.100 g-1.min-1 in untreated aged and adult groups, 90 minutes after infarction [P < .05]). Pretreatment also reduced cortical edema; mean cortical specific gravity 4 hours after infarction was 1.0381 +/- 0.0013 in untreated aged rats and 1.0391 +/- 0.0014 in untreated adults compared with 1.0458 +/- 0.0031 in treated aged rats and 1.0442 +/- 0.0014 in treated adult rats (P < .05)., Conclusions: Under similar experimental conditions, there was an age-related increase in cerebral infarct size. However, NMDA receptor antagonism was neuroprotective in the aging brain and resulted in a significant reduction in cerebral ischemic damage, less cortical edema, and preservation of cerebral blood flow.

Cortical thermal clearance provides a practical means of continuous assessment of cerebral blood flow. A probe which can be used to monitor cerebral cortical thermal clearance is described. It has proved a reliable method of predicting oligaemia, showing good correlation between measured thermal clearance and the onset of clinical signs of ischaemia. The limitations are its size, invasiveness, small sample volume and difficulty with quantification. It is a useful additional tool in the management of patients suffering from acute neurosurgical disorders.

The cortical thermal clearance (CTC) was recorded continuously during surgery for a giant basilar aneurysm under cardio-pulmonary bypass. The changes observed mirrored the fall and rise in cardiac output. CTC at zero flow corresponded closely to the established cadaveric value, supporting the principle that the conductive component of thermal clearance is constant.

A model of occlusive stroke in the aging brain has been developed and used to evaluate the effects of age upon cerebral infarction, cerebral oedema and neuroprotective potential. Focal ischaemia following left middle cerebral artery occlusion has been compared in aged (30 month) and adult (< 17 month) rats, with histological assessment of infarct volume and analysis of specific gravity as an index of cerebral oedema. Aging was associated with a significant increase in cerebral infarct size. The mean infarct volume in aged rats was 40.5% +/- 2.6% of the hemisphere volume, compared to 30.9% +/- 0.7% in adults (p < 0.01). Pre-treatment with the competitive N-Methyl-D-Aspartate (NMDA) receptor antagonist 3-(2-Carboxy Piperazin-4-yl)Propyl-l-Phosphonate (D-CPP-ene) reduced infarct volumes in both age groups to 33.0% +/- 1.8% and 20.7% +/- 3.2% in aged and adult animals, respectively (p < 0.05). There was significantly less oedema of the cerebral cortex in D-CPP-ene pre-treated rats; mean cortical specific gravity 4 hours post-infarction was 1.0381 +/- 0.0013 in untreated aged rats and 1.0391 +/- 0.0014 in untreated adults, compared to 1.0458 +/- 0.0031 in treated aged rats and 1.0442 +/- 0.0014 in treated adults (p < 0.05). At 24 hours post-infarction, D-CPP-ene pre-treated aged rats had a mean cortical specific gravity of 1.0403 +/- 0.0006 compared to 1.0361 +/- 0.0014 in untreated aged animals (p < 0.05). This study has demonstrated an age-related increase in cerebral infarct size, but has shown that the aging brain is amenable to neuroprotection by NMDA receptor antagonism.

The effects of pre-treatment with the NMDA receptor antagonists MK-801 and D-CPPene on the development of brain oedema were investigated in a rodent model of intracerebral haemorrhage. In acute experiments (4 hour survival) both drugs caused significant hypotension and had significant anaesthetic effects whilst conferring no protection against oedema formation. In chronic experiments (24 hour survival) MK-801 conferred no protection against brain oedema. With D-CPPene marginal protection against cortical oedema may have been conferred but this result should be interpreted with caution.

Cortical thermal clearance was used during surgery for clipping of a giant middle cerebral artery (MCA) aneurysm. During prolonged continuous proximal MCA occlusion thermal clearance remained normal, indicating sufficient collateral blood supply. Postoperatively the patient had no neurological deficit. This monitoring technique is a useful guide to the safety of temporary clipping during aneurysm surgery.

Thermal clearance has been used as a measure of tissue blood flow for over 60 years. We have developed a probe which can be used to monitor cerebral cortical thermal clearance in patients suffering from acute neurosurgical disorders. Despite its limitations of size, invasiveness, small sample volume, and difficult quantification it has proved a reliable method, showing a good correlation between measured thermal clearance and the onset of clinical signs of ischaemia.

The effect of global immunosuppression by sublethal whole body X-irradiation on the development of cerebral oedema was assessed 24 h after right middle cerebral artery occlusion in the rat. Irradiation produced a significant leukopenia and thrombocytopaenia, and significantly reduced cortical oedema when compared to non-irradiated control animals.