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.

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.

Continuous cerebral compliance monitoring in severe head injury: its relationship with intracranial pressure and cerebral perfusion pressure

BACKGROUND

Cerebral compliance expresses the capability to buffer an intracranial volume increase while avoiding a rise in intracranial pressure (ICP). The autoregulatory response to Cerebral Perfusion Pressure (CPP) variation influences cerebral blood volume which is an important determinant of compliance. The direction of compliance change in relation to CPP variation is still under debate. The aim of the study was to investigate the relationship between CPP and compliance in traumatic brain injured (TBI) patients by a new method for continuous monitoring of intracranial compliance as used in neuro-intensive care (NICU).

METHOD

Three European NICU's standardised collection of CPP, compliance and ICP data to a joint database. Data were analyzed using an unpaired student t-test and a multi-level statistical model.

RESULTS

For each variable 108,263 minutes of data were recorded from 21 TBI patients (19 patients GCS</=8; 90% male; age 10-77 y). The average value for the following parameters were: ICP 15.1+/-8.9 mmHg, CPP 74.3+/-14 mmHg and compliance 0.68+/-0.3 ml/mmHg. ICP was >/=20 mmHg in 20% and CPP<60 mmHg for 10.7% of the time. Compliance was lower (0.51+/-0.34 ml/mmHg) at ICP>/=20 than at ICP<20 mmHg (0.73+/-0.37 ml/mmHg) (p<0.0001). Compliance was significantly lower at CPP<60 than at CPP>/=60 mmHg: 0.56+/-0.36 and 0.70+/-0.37 ml/mmHg respectively (p<0.0001). The CPP - compliance relationship was different when ICP was above 20 mmHg compared with below 20 mmHg. At ICP<20 mmHg compliance rose as CPP rose. At ICP>/=20 mmHg, the relation curve was convexly shaped. At low CPP, the compliance was between 0.20 and 0.30 ml/mmHg. As the CPP reach 80 mmHg average compliance was 0.55 ml/mmHg., but compliance fell to 0.40 ml/mmHg when CPP was 100 mmHg.

CONCLUSIONS

Low CPP levels are confirmed to be detrimental for intracranial compliance. Moreover, when ICP was pathological, indicating unstable intracranial equilibrium, a high CPP level was also associated with a low volume-buffering capacity.

Assessment of the relationship between age and continuous intracranial compliance

The aim of this open, descriptive and prospective study was to determine if the new monitoring parameter "continuous intracranial compliance (cICC)" decreases with age in patients with traumatic brain injury (TBI). 30 patients with severe and moderate TBI (Glasgow Coma Scale score < or = 10) contributing to a European multicenter study, organized by the Brain-IT group, underwent computerized monitoring of blood pressure, intracranial pressure (ICP), cerebral perfusion pressure and cICC. Regression analyses of individual median ICP and median cICC versus patients' age revealed no significant dependency. Median cICC declined significantly with increasing ICP (when median ICP = 10, 20 and 30 mmHg, cICC = 0.64, 0.56 and 0.42 ml/mmHg respectively, p < 0.05). These three ICP groups were then subdivided according to age (0-20, 21-40, 41-60 and 61-80 years). Median cICC declined with age in both high ICP groups (median ICP = 20,30 mmHg). Percentage cICC values below a set pathological threshold of lower than 0.05 ml/mmHg across the four age groups were 28% (0-20 yrs), 59% (21-40 yrs), 60% (41-60 yrs) and 70% (61-80 yrs) respectively. The observed phenomenon of decreased intracranial volume challenge compensation with advancing age may contribute to the well-known fact of a worse outcome in elderly patients after TBI.

Bench test assessment of the new Raumedic Neurovent-P ICP sensor: a technical report by the BrainIT group

BACKGROUND

In clinical practice, fiberberoptic and piezo-electric ICP probes are often used for measuring intracranial pressure (ICP). A number of similar technologies, although performing well in bench test studies, have been shown to exhibit unacceptable zero drift, fragility or both during trials conducted under clinical conditions. Recently, a new technology has become available, the Neurovent-P (Raumedic AG + CO, Raumedic, Germany). As a pre-requisite for a clinical trial, we have conducted and report on bench test studies to confirm the manufacturer's long term zero-drift performance for this technology.

METHOD

In a test rig static tests (recording of 20 mmHg pressure) and dynamic tests, ranging from 5 to 50 mmHg have been performed.

FINDINGS

10 ICP probes have been tested for a total of 60 days. All the catheters, after the connection with the ICU monitor displayed a static pressure of 0 +/- 1 mmHg and did not required pre-insertion alteration. At five days, mean zero drift was 0.6 +/- 0.9 mmHg. Overall, zero drift ranged from 0 to 2 mmHg. At a fixed static pressure of 20 mmHg, the mean recorded value was 20.6 +/- 0.8 mmHg, ranging from 19 to 23 mmHg. A regression analysis of the relationship between the applied pressure and the recorded pressure during the dynamic tests of the 10 catheters yielded a correlation coefficient R2 of 0.997. Applying the Altman and Bland method to assess the bias and confidence limits for the Raumedic catheter responses during the dynamic tests against the applied gold-standard hydrostatic column pressures, the average bias of -0.66 +/- 0.85 mmHg, with 95% CLs of -2 mmHg and 1 mmHg.

CONCLUSIONS

Mean zero drift, after five days, was very small and long-term continuous recording of a stable pressure was very precise. The response at dynamic tests, i.e. the changes of pressure in a wide range, was excellent. The average bias of the Raumedic catheter compared with the hydrostatic column is very small. After this bench test, the next and most critical step will be to conduct a trial of this promising technology under more demanding clinical environment.

R3-Survey of traumatic brain injury management in European Brain IT centres year 2001

OBJECTIVE

To obtain knowledge about the conditions and management of traumatic brain injury (TBI) in a collaborative network of Brain Information Technology centres.

DESIGN

The Brain IT (Brain monitoring with Information Technology) survey comprised two parts: local conditions and policies (part A), and a case study part (part B). The information was gathered by written questionnaires followed by telephone interviews.

PARTICIPANTS

Twenty-four Brain IT centres participated (two respondents from 18 sites).

RESULTS

The average proportion of agreement between duplicate respondents was 0.79 (range 0.44-1.00). All Brain IT centres monitored ICP. The reported order of treatment for intracranial hypertension was: evacuation of mass-lesions and head elevation (1), increase of sedation and Mannitol scheme (2), hyperventilation (3), ventricular drainage (4), craniectomy and pentothal coma (5), and decompressive lobectomy (6). The respondents were less prone to evacuate expansive contusions in relation to extra cerebral hematomas. The most common suggested interventions (alone or in combination) for treatment of intracranial hypertension without mass lesions was the Mannitol scheme (included in 71% of the suggestions), CSF drainage (included in 56%), hyperventilation (included in 32%), and pentothal coma (included in 22%).

CONCLUSIONS

The suggested management of TBI was mainly in accordance with published guidelines, although a minor proportion of the answers deviated to some extent. The suggested order and combinations of different treatment interventions varied. Variation of treatment within the range of prescribed standards provides optimal conditions for an interesting future analysis of treatment and monitoring data as collected prospectively in a Brain IT database.

[Moderate hypothermia in traumatic brain injury: results of clinical trials]

The concept of neuroprotection' by hypothermia dates back to ancient times. This paper reviews the results of clinical trials using mild hypothermia (3235 degrees C) in patients with severe traumatic brain injury over the past decade. Induced hypothermia has been used in experimental models mostly to prevent or attenuate secondary neurological injury and has been used to provide neuroprotection in traumatic brain injury, both in animal models and clinical trials. Results from animal experiments largely confirm that hypothermia can provide protection for the injured brain; however, the results from clinical trials and from a number of meta-analyses have been conflicting. This paper reviews the evidence and explores possible reasons for the mixed results from clinical trials. Hypothermia is clearly effective in controlling intracranial hypertension. Early favourable results on neurological outcome and mortality were not confirmed in a subsequent multi-center trial. Subsequently, single-centre studies, with quicker induction of hypothermia and longer duration of cooling, again reported benefits on outcome. These differences may be explained by differences in study protocols (i.e. speed and duration of cooling, speed of re-warming), prevention of side effects and various supportive measures in the ICU. Although induced hypothermia appears to be a highly promising treatment in various forms of neurological injury including traumatic brain injury, the difficulties in realising its therapeutic potential are underscored by the negative results from a large multi-center trial. Routine usage of hypothermia in traumatic brain injury can not currently be recommended.

The BrainIT group: concept and core dataset definition

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 post-hoc hypothesis testing. In Part A, the underlying concept, the group coordination structure, membership guidelines and database access and publication criteria are described. Secondly, in part B, we describe a set of meetings funded by the EEC that allowed us to define a "Core Dataset" and we present the results of a feasibility exercise for collection of this core dataset.

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 paper based pilot collection of data was conducted to determine the feasibility for collection of the core dataset. Specially designed forms to collect the core dataset demographic and clinical information as well as sample the time-series data elements were distributed by both email and standard mail to 22 BrainIT centres. A deadline of two months was set to receive completed forms back from centres. A pilot data collection of minute by minute physiological monitoring data was also performed.

FINDINGS

A core-dataset was defined and can be downloaded from the BrainIT web-site (go to "Core dataset" link at: www.brainit.org). Eighteen centres (82%) returned completed forms by the set deadline. Overall the feasibility for collection of the core data elements was high with only 10 of the 64 questions (16%) showing missing data. Of those 10 fields with missing data, the average number of centres not responding was 12% and the median 6%. An SQL database to hold the data has been designed and is being tested. Software tools for collection of the core dataset have been developed. Ethics approval has been granted for collection of multi-centre data as part of a pilot data collection 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 multi-centre trials of new health care technology in patients with traumatic brain injury.

Treatment of fever in neurosurgical patients

Even moderate temperature elevations soon acute cerebral damage may markedly worsen initial brain injury. These effects may justify aggressive antipyretic treatment in neurosurgical intensive care unit (NICU). On the basis of a literature survey, it is observed that fever is extraordinarily common in the neurosurgical intensive care unit during the acute phase of subarachnoid hemorrhage, stroke, and traumatic brain injury. Several clinical studies also suggest worsened neurologic outcome in patients who are febrile compared to those who are not. Pyrexia is more frequent in infected than noninfected patients. Infections (mainly in the respiratory tract) are usually diagnosed in the majority of febrile NICU patients. Laboratory investigations are quite clear regarding the adverse effects of fever in terms not only of functional outcomes, but also histological and neurochemical injury. Even though fever may cause diagnostic confusion (central fever vs infectious), the potentially devastating effects of pyrexia in patients with cerebral diseases may proceed to treat in any case. An attempt to correct fever appears warranted in all patients with acute cerebral damage in order to obtain a better functional recovery and to limit maximally any further insult to the brain. Some of the more common and innovative methods to control body temperature in order to mitigate the detrimental effects of pyrexia following acute neurological injury are explored. Maintenance of normothermia appears to be a desirable therapeutic goal in managing the patients with damaged or at-risk brain tissue. However, it has not been established conclusively that the benefits of antipyretic therapy outweigh its risks and that despite a sound physiologic argument for controlling fever in the brain-injured patient, there is no evidence that doing so will improve their outcome.

[Neuro-link, an Italian traumatic coma data bank: what did we learn from the first 1000 patients and how can we do better? ]

To understand the complex physiopathology of post-traumatic brain damage is important to have data on epidemiology, clinical course, monitoring, effect of therapy and outcomes. In 1997 3 neuro-intensive care units in the Milan metropolitan area developed a computer assisted database named Neuro-Link (NL) for collection of information on head injury. All head injured patients requiring intensive care during the first 24 hours post-trauma were eligible. The data collection form was designed for use with a computer interface to cover: 1) general, previous and admission data; 2) secondary insults and complication; 3) CT scan and monitoring data; 4) outcome data. Two different data collections were performed: 1) NL domestic (data from 3 centres from 1997); 2) NL 18 centres (3 month survey of Italian centres with interest in neurotrauma care). An audit of the data was performed. NL domestic included 1 085 patients from 1997 to 2002. NL 18 centres included 282 patients in the 3 month period. Audit is performed on 35 000 data per year.A large number of good quality information on head injury patients is now available. The database is useful for: 1) production of information; 2) base for prospective studies.

Continuous cerebral compliance monitoring in severe head injury: its relationship with intracranial pressure and cerebral perfusion pressure

Cerebral Compliance describes the ability of cranial content to accommodate volume variations. Intracranial vascular compartment is thought to be one of the most important determinants of Compliance. Cerebral perfusion pressure (CPP) has a significant influence upon the calibre of cerebral vessels and consequently, upon blood volume. This study was designed to investigate the influence of CPP on intracranial volumes balance, described by cerebral compliance, in severe traumatic brain injured patients (TBI). Nine TBIs were studied. The Spiegelberg ventricular catheter continuously measured ICP and Compliance. Compliance, CPP and ICP were digitally collected for a total of 737 hours of monitoring (44239 total data). Compliance was lower at CPP < 60 than at CPP > or = 60 (0.51 +/- 0.3 versus 0.64 +/- 0.3 ml/mmHg). The ICP level influenced the relation between CPP and Compliance. At ICP < 20 (LICP; 80.3% of data) Compliance and CPP were not significantly related. At ICP > or = 20 mmHg (HICP; 19.7% of data), Compliance varied with changes in CPP. When CPP < 60 mmHg, Compliance showed a trend to decrease as CPP decreased (R2 = 0.85). At CPP > or = 60 mmHg Compliance decreased with CPP (R2 = 0.83). In the range of low CPP vasoparalysis is impending. However, when ICP is pathological, at high CPP our results may express vasodilatation instead of expected vasoconstriction from normal autoregulation.

Multi-centre assessment of the Spiegelberg compliance monitor: interim results

Analyses of a multi-centre database of 71 patients at risk of raised ICP showed that in head injured patients (n = 19) and tumour patients (n = 13) clear inverse relationships of ICP vs compliance exist. SAH patients (n = 5) appear to exhibit a biphasic relationship between ICP and compliance, however greater numbers of patients need to be recruited to this group. Patients with hydrocephalus (n = 34) show an initial decrease in compliance while ICP is less than 20 mmHg, thereafter compliance does not show a dependence upon ICP. A power analysis confirmed that sufficient numbers of patients have been recruited in the hydrocephalus group and a ROC analysis determined that a mean compliance value of 0.809 (lower and upper 95% CL = 0.725 & 0.894 resp.) was a critical threshold for raised ICP greater than 10 mmHg. Preliminary time-series analyses of the ICP and compliance data is revealing evidence that the cumulative time compliance is in a low compliance state (< 0.5 ml/mmHg), as a proportion of total monitoring time, increases more rapidly than the cumulative time ICP is greater than 25 mmHg. Before trials testing compliance thresholds can be designed, we need to consider not just the absolute threshold, but the duration of time spent below threshold. A survey may be required to identify a consensus of what is the minimum duration of raised ICP above 25 mmHg needed to instigate treatment.

Emergency system prospective performance evaluation for cardiac arrest in Lombardia, an Italian region

BACKGROUND

The aim of this research is to evaluate quality of out-of-hospital medical services in our country, using performance indicators and a new computerised database.

METHODS

(a)

EXPERIMENTAL DESIGN

Data were collected prospectively in three emergency dispatch centres for 90 days. Follow-up was evaluated at 1 day and 1 month after the event. This paper presents data on the cardiac arrest cohort only. (b)

SETTING

Three emergency dispatch centres in Lombardia. (c)

PATIENTS

One hundred and seventy-eight patients in non-traumatic cardiac arrest were enrolled. (d)

INTERVENTIONS

None. The study was observational only.

RESULTS

Mean interval between phone call and arrival on scene was 8.5+/-3.5 min. BLS manoeuvres were carried out from bystanders only in 15% of the cohort; this was associated with significant mortality reduction (85.7 versus 95.8%, chi(2) P<0.05). One hundred and thirty-three patients (75%) received assistance from BLS crews while only 45 patients (25%) were assisted by ALS medical personel, with a significant mortality reduction (ALS deaths 86.7%, BLS deaths 97%). Total 24 h survival was 9% and survival at 1 month declined to 6.17%.

CONCLUSIONS

Quality monitoring produces objective information on interventions and outcomes. Only with this information, is it possible to implement improvement programmes that are planned according to the data presented.

[Steroids in acute spinal cord injury. An unproven standard of care]

Since 1990s, methylprednisolone has become a widely prescribed therapy for improving the outcome of acute spinal cord injured victims and has considered a standard of care based. This have been claimed on the results of two randomized controlled trials (NASCIS II and III), even if the studies failed to demonstrate improvements due to methylprednisolone administration in any of the a priori hypothesis tested. Although, post hoc analyses were carefully constructed for evidencing minimal benefits of the steroid therapy in subgroups of patients and were publicized worldwide, these presumed benefit have been extended to all acute spinal cord injured patients. Further analyses of the papers, devoid of the participation of the authors, performed by external reviewers and evidence-based experts, failed to demonstrate clinically significant treatment effects. For this reason and for the consideration that high dose methylprednisolone could be harmful to the patients, the use of methylprednisolone in acute spinal cord injury cannot be recommended and cannot be considered a standard of care.

[Role of assisted breathing in severe traumatic brain injury]

BACKGROUND

Based on available data, there is no definite clinical research describing option, timing and effects of assisted as opposed to controlled ventilation to successfully treat acute severely brain-injured patients. This study demonstrates pressure support ventilation as a possible alternative to controlled ventilation in the acute phase of brain injury. We illustrated which factors influenced the shift from total (CPPV) to partial ventilatory support (PS-SIGH) and the consequences of assisted ventilation on cerebral hemodynamics.

METHODS

a)

EXPERIMENTAL DESIGN

Retrospective, cohort study. b)

SETTING

Adult intensive care unit of a university hospital. c) Patients population: Forty-two severe head-trauma victims (GCS </= 8). d) Measures and interventions: Ventilation modalities and parameters, systemic and cerebral hemodynamics [Intracranial pressure (ICP), cerebral perfusion pressure (CPP), jugular bulb oxygen saturation (SjvO(2))] data were collected daily and described.

RESULTS

Controlled ventilation was the main ventilatory support during the very first moment of brain trauma. Percentage of patients ventilated with pressure support increased progressively (37.5% on day 2) and was the dominant method of ventilation on the fourth day. Worst neurologic condition and more elevated ICP were associated to controlled ventilation. Carbon dioxide partial pressure was higher in PS-SIGH, however, it was not correlated with significantly elevated ICP.

CONCLUSIONS

In traumatic brain injured patients, ICP and CPP monitoring, together with neurological examination are the main factors influencing the selection of ventilatory assistance. It is evident from these data that assisted ventilation is a feasible and safe alternative to controlled ventilation even in the acute phase of trauma if intracranial parameters are continuously monitored and controlled.

Multi-centre assessment of the Spiegelberg compliance monitor: preliminary results

Acute brain injury states (e.g. head injury, subarachnoid haemorrhage) show clear inverse relationships of ICP vs compliance, with ICP instability at times of lower compliance states. Variance in compliance values is large in hydrocephalus where ICP is relatively lower and compliance higher. Nonetheless, early experience shows that compliance data influence decisions on CSF diversion treatments. Future work will focus on the ability of intracranial compliance to predict ensuing ICP instability and methodological refinement for monitoring patients who have higher compliance states.

Induced abdominal compartment syndrome increases intracranial pressure in neurotrauma patients: a prospective study

OBJECTIVE

To evaluate the effect of a stepwise increase in intra-abdominal pressure (IAP) on intracranial pressure (ICP) and to further define the pressure transmission characteristics of different body compartments.

DESIGN

A prospective, nonrandomized study.

SETTING

A multidisciplinary intensive care unit at a university medical center.

PATIENTS

Fifteen patients with moderate-to-severe head injury.

INTERVENTIONS

All patients were studied after the initial stabilization and resolution of intracranial hypertension. Measurements were carried out before and 20 mins after IAP was increased by positioning a soft, 15-L water bag on the patient's abdomen.

MEASUREMENTS AND MAIN RESULTS

Placing weights upon the abdomen generated a significant increase in IAP, which rose from 4.7 +/- 2.9 to 15.5 +/- 4.1 mm Hg (p <.001). The rise in IAP caused concomitant and rapid increases in central venous pressure (from 6.2 +/- 2.4 to 10.4 +/- 2.9 mm Hg; p <.001), internal jugular pressure (from 11.9 +/- 3.2 to 14.3 +/- 2.4 mm Hg; p <.001), and ICP (from 12.0 +/- 4.2 to 15.5 +/- 4.4 mm Hg; p <.001). Thoracic transmural pressure, calculated as the difference between central venous pressure and esophageal pressure, remained constant during the protocol. Respiratory system compliance decreased from 58.9 +/- 9.8 to 44.9 +/- 9.4 mL/cm H2O (p <.001) in all patients because of decreased chest wall compliance. The mean arterial pressure increased from 94 +/- 11 to 100 +/- 13 mm Hg (p <.01), which allowed the maintenance of a stable cerebral perfusion pressure (82.4 +/- 10.3 vs. 84.7 +/- 11.5 mm Hg; p = NS) despite the ICP increase.

CONCLUSIONS

Increased IAP causes a significant rise in ICP in head trauma patients. This effect seems to be the result of an increase in intrathoracic pressure, which causes a functional obstruction to cerebral venous outflow. Routine assessment of IAP may help clinicians to identify remediable causes of increased ICP. Caution should be used when applying laparoscopic techniques in neurotrauma patients.

Neuro-Link, a computer-assisted database for head injury in intensive care

Reliable information is vital for clinical trials, so we developed a database, for head trauma victims admitted to neuro-intensive care units (NICU). This database, first step in a sequential project, comprises 176 selected fields mainly focused on the early post-traumatic phase and has a user-friendly computerized interface. The software was tested for a trimester in 18 Italian neuro-intensive care units. The paper describes the main features of the database, the results of a three months' data collection test, its limitations and its potential improvements. A description of the database fields and a brief summary of the 282 patients included so far are also presented.

Control of fever by continuous, low-dose diclofenac sodium infusion in acute cerebral damage patients

OBJECTIVES

The aim of this study was to assess the efficacy and safety of low doses of diclofenac sodium (DCF) in attaining normothermia with minimal major side effects in patients with acute cerebral damage. The study was designed to verify the adequate, prolonged antipyretic action of DCF infusion, to quantify its haemodynamic and cerebral impact and to assess any negative effect on renal and liver function.

DESIGN

Retrospective, cohort study on prospectively collected data.

SETTING

Intensive care unit (ICU) of a university hospital.

PATIENT POPULATION

Five patients with subarachnoid haemorrhage and seven severe head-trauma victims with febrile illness of various infectious origin.

INTERVENTIONS

Continuous i.v. infusion of a low dose (0.04 mg/kg/h) of DCF for 48 h.

MEASUREMENTS AND RESULTS

Systemic and cerebral haemodynamic data were collected at 4 h intervals for 8 h before diclofenac infusion and 48 h after. Renal and liver functions were monitored. Normothermia, defined as external temperature < 37.5 degrees Celsius (degrees C), was achieved in all cases. Intracranial pressure was significantly lowered and mean arterial pressure was unaffected, so cerebral perfusion pressure rose after DCF. Hepatic and renal function were not altered in the 48 h post DCF. Mean urinary output was preserved at high flow and was not influenced by DCF.

CONCLUSIONS

Continuous infusion of low-dose DCF attained normothermia without any major cerebral or systemic side effects. Renal and liver functions were unaffected. Once normothermia was achieved, intracranial and cerebral perfusion pressure improved.

Guidelines for the treatment of adults with severe head trauma (part II). Criteria for medical treatment

Since 1995 a Group of Italian Neurointensivists and Neurosurgeons belonging to the Italian Societies of Neurosurgery (SINch) and Anesthesia & Intensive Care (SIAARTI) has produced some recommendations for treatment of adults with severe head trauma. They have been published in 3 parts: Part I (Initial assessment, Evaluation and pre-hospital treatment, Criteria for hospital admission, Systemic and cerebral monitoring), Part II (Medical treatment) and Part III (Surgical treatment criteria). These recommendations reflect a multidisciplinary consent and are mostly based on expert opinion. The main aim is to provide a practical reference for all those dealing with severe head injuries from first-aid to intensive care units, setting out the minimal goals of management to be reached throughout the Country. These recommendations need a continuous critical review and updating. Medical treatment is aimed at preventing or minimizing secondary brain damage following acute brain injury, provided that surgical masses have been promptly identified and removed. In order to assure cerebral perfusion, systemic hemodynamics and respiratory exchanges should be normal. Volemia is crucial, and mean arterial pressure should remain above 90 mmHg. Good general intensive care, including gastroprotection, water-electrolyte balance, infection control, nutrition and physiotherapy, is assumed as the basis for brain-oriented therapy. Intracranial hypertension requires an approach based on various steps. First, factors that can directly rise intracranial pressure (ICP) such as venous outflow obstruction, fever, pain etc. should be checked and corrected. Second, Mannitol, CSF withdrawal, sedation and moderate hyperventilation should be applied. This can be done by targeting specific problems with specific treatment (which is possible when the cause of ICP rise is known) or in a step-wise approach, by using less aggressive interventions before than more aggressive ones, with a higher risk of complications. Third, extreme treatment, such as barbiturates, should be reserved to cases with refractory intracranial hypertension. The main goal of ICP treatment is not simply ICP reduction, but the maintenance of adequate cerebral perfusion pressure.

Guidelines for the treatment of adults with severe head trauma (part III). Criteria for surgical treatment

The Guidelines of the surgical management of severe head injury in adults, as evolved by the Neurotraumatology Group of the Italian Neurosurgery Society and the Italian Society for Anaesthesia, Analgesia, Reanimation and Intensive Care are presented and briefly discussed. Guidelines presented here are of a pragmatic nature, based on consensus and expert opinion. Aspects pertaining to specific indications to surgery and/or to the possibility of conservative management of different traumatic intracranial lesions are highlighted. The importance of surgery in preventing secondary insults to the traumatised brain is emphasised.

Guidelines for the treatment of adults with severe head trauma (part I). Initial assessment; evaluation and pre-hospital treatment; current criteria for hospital admission; systemic and cerebral monitoring

If pragmatic recommendations for treatment of severely head-injured patients could really be applied, they would probably have a considerable impact in terms of reduction in mortality and disability. Since 1995 a Group of Italian Neurointensivists and Neurosurgeons belonging to the Italian Societies of Neurosurgery (SINch) and Anesthesiology & Intensive Care (SIAARTI) has produced this first part of recommendations that are completed by Medical treatment (Part II) and Surgical treatment criteria (Part III). These recommendations reflect a multidisciplinary consent but are based on scientific evidence, when available, and take origin mainly from expert opinions and the current clinical and organizational situation. For this aspect they differ from other American and European guidelines, which are strictly based on criteria of proven efficacy. These recommendations aim at providing a practical reference for all those dealing with severe head injuries from first-aid to intensive care units, setting out the minimal goals of management to be reached throughout the country. For these reasons they need continual critical review and updating. Main clinical aims are: 1) to prevent secondary cerebral damage by continuous and meticulous maintenance of systemic homeostasis 2) to standardize methods of neurological evaluation and CT scan classification and scheduling; 3) to give simple indications for systemic and cerebral monitoring 4) to pragmatically discuss the organizational scenarios and specify the minimal safe clinical approach when patients are treated in non-specialized settings. Briefly, smooth tracheal intubation and ventilation in all comatose patients, administration of rapidly metabolized sedative and analgesic drugs to permit frequent neurological evaluation, restoration of volemia and systolic blood pressure above 110 mm Hg, oxygen saturation >95% and normocapnia, are all recommended from the very early treatment and transport. Homogeneity of language, reliable and correctly tested Glasgow Coma Score and pupillary reflexes, and a simple CT scan classification are recommended to improve communications and clinical decisions in the multidisciplinary setting of management. In comatose patients, cerebral perfusion pressure, intracranial pressure and oxygen jugular saturation must be monitored according to specific criteria, which are described. Therapy with hyperventilation and mannitol should be used only in case of clinical deterioration and uncal herniation. This therapy could be useful to gain time to reach neurosurgery. The aim of these recommendations is to achieve safer management of severely brain injured patients, immediate diagnosis of clinical deterioration and successful identification and treatment of surgical lesions. The impact of these guidelines requires further verification.

[What kind of monitoring of intracranial pressure]

Intracranial pressure monitoring is an essential element of severe head injury monitoring. In the Italian reality, this monitoring still has not become diffusely utilised. In this paper are analysed, using the available data obtained from the Neurolink database, the information from the more advanced Italian neurotrauma centres. Only 50% of the patients, in which monitoring is indicated, are monitored. Synthetically will be reviewed the indications to the monitoring, the advantages offers from such procedure, the modalities of monitoring considering also the economic impact and the risks legacies to the procedure.

[What will jugular bulb oxygen saturation monitoring tell?]

Global cerebral oxygenation can be measured by means of a catheter introduced in the internal jugular vein and placed retrograde in the jugular bulb. The measure of oxygen saturation sampled from the jugular vein (SjvO2) depends on cerebral metabolism and blood flow. This parameter describes the relative balance between oxygen delivery to the brain and oxygen consumption by the brain. SjvO2 remains normal until cerebral blood flow is proportional to cerebral metabolic demands. Any disturbances that increase cerebral metabolism and/or diminishes cerebral oxygen supply determines a reduction of SjvO2. Correspondingly, a decrease of oxygen consumption and/or an increase of oxygen supply may induce an increase of SjvO2. Therefore, SjvO2 is a useful monitor to assess the adequacy of cerebral circulation in patients with neurologic illness, allowing detection of state of hypoperfusion. Monitoring cerebral oximetry in comatose patients is of great importance in order to prevent, detect, control and understand secondary brain insults and damage which are mainly ischemic/hypoxic in nature. Although SjvO2 was shown to be highly sensitive in the presence of global hypoxia or ischemia, the occurrence of focal ischemia may still go undetected. Besides this, elevated SjvO2 should not be universally interpreted as hyperaemia. Instead, the presence of an elevated SjvO2 is a heterogeneous condition. Increased SjvO2 may be alarming prognostic indicators that carry important implications for comatose patients management.

Jugular saturation (SjvO2) monitoring in subarachnoid hemorrhage (SAH)

Jugular saturation (SjvO2) monitoring was performed in 26 SAH patients to evaluate the incidence of normal (0.56-0.74) and pathological SjvO2 values in this population and to describe its time course in the first 12 days. We also attempt to quantify the influence of systemic and cerebral hemodynamics on SjvO2 and to assess the relationship between cerebral injury volume measured on CT scan and SjvO2. Mean SjvO2 was 0.66 +/- 0.07 (354 samples, median 0.67, range 0.43-0.89). 73% of the observations (259/354) were in the normal range. On serial measurements, we identified only 37/354 (10%) desaturation episodes (D.E.). ICP was significantly higher during low SjvO2 observation (p = 0.008). No statistical differences were noted regarding the influence of MAP, CPP, PaCO2, PaO2 on SjvO2 but during D.E., lower PaCO2 and CPP were more frequently observed. CT scan lesions > 25 ml were associated initially with lower SjvO2 values and with higher values at second CT.

[The use of jugular saturation in monitoring patients with subarachnoid hemorrhage ]

We evaluated the usefulness of monitoring jugular saturation (SjO2) in subarachnoid haemorrhage patients. SjO2 is an index of the global ratio between cerebral blood flow and metabolism. Low SjO2 identified global cerebral flow reduction, as due to low cerebral perfusion pressures or hypocapnia, but not regional ischemic phenomena related to vasospasm.

[Cerebral blood flow in subarachnoid hemorrhage]

Cerebral blood flow (CBF) following subarachnoid haemorrhage varies according to the time of sampling, with regard to the time of bleeding, to clinical conditions of patients and to any possible occurrence of vasospasm. CBF is proportionally reduced upon clinical conditions, involves the totality of patients and represents a diffuse bilateral phenomenon, not dependent on the location of the aneurysm. Following events, such as vasospasm, may deteriorate haemodynamic conditions, especially when unstable. Thus, CBF monitoring is necessary and useful in these patients. The evaluation of this parameter, according to the metabolic demands, appears rather fundamental. Besides, during the first two weeks, all the available therapeutic strategies have to employed in order to achieve the best optimization of the CBF so as to avoid the occurrence or at least minimising the extent of ischemic cerebral lesions.

[Surgical versus endovascular treatment in cerebral aneurysm. The opinion of a neurosurgeon]

The high risk of rebleeding of ruptured aneurysms imposes the need of their early exclusion from arterial circulation. The onset of endovascular technique of embolization gives a new chance, making, time by time, necessary the choice for the best treatment. The advantages and limits of surgical option are well known and consolidated. The results of endovascular technique are similar in the acute phase, but it lacks an adequate follow up and a clear definition of some technical knowledges. Clinical and anatomical data and a serious analysis of specific technical difficulties of both methods must condition the choice of treatment. Present experience allows us to give sure indications only for certain cases, whereas final landmarks are indisposable in many other situations. However, the team discussion between the neurosurgeon, the neuroradiologist and the neuroreanimator must be the crucial point of the decisional way in every single case.

Incidence of asymptomatic berry aneurysms among patients undergoing carotid endarterectomy

BACKGROUND

Scattered reports of literature suggest the hypothesis that patients suffering from a severe stenosis of extracranial carotid artery may present an increased rate of intracranial berry aneurysms caused by the hemodynamic stress on the side opposite to the stenosis, namely on physiological shunts. However, this hypothesis has never been verified upon a large and homogeneous series focused on the argument.

MATERIALS AND METHODS

We reviewed a consecutive series of 405 patients submitted to carotid endarterectomy for stenosis greater or equal to 70%.

RESULTS

Thirteen aneurysm were found in 11 patients (2.6%). Our patients showed a slight increase of incidence regards to general population (1%), maybe due to the large number of aged patients among our subpopulation. Preoperative TCD evaluation showed the presence of increased flow velocities in the physiological shunts, namely the anterior cerebral artery and the anterior communicating artery, in 65% of the patients, and angiography confirmed the redistribution of intracranial circulation. Nevertheless, according to aneurysm location, no statistically significant correlation (0.3 < p < 0.4) was found between the presence of an aneurysm and the values of velocity in these arteries.

CONCLUSIONS

As regards the etiology of berry aneurysms, these data suggest that increased hemodynamic stress per se is not sufficient to cause the origin of berry aneurysms. Maybe, a role is possible only if either congenital, or acquired and age-related factor, peculiar of cerebral arteries, coexist.

[Adequacy of admission in neurosurgical intensive care]

OBJECTIVE

The Intensive Care Units of Milano metropolitan area are characterized by difficulties of hospitalization for acutely injured patients due to the low bed availability. We evaluated the problem trying to find out possible solutions.

DESIGN

On the day of achieved neurological and neurosurgical stability-defined as the day when the intracranial pressure and jugular venous oxygen saturation monitoring, hyperventilation, osmotic therapy were considered no longer needed--the monitoring procedures and instrumental and/or pharmacological treatments that the patients received were recorded and classified as follows: 1) intensive, 2) intermediate, 3) non-intensive.

PATIENTS

All the acutely injured patients admitted at five Neurosurgical ICUs during June-July and October-November 1994 have been studied. Only one of these ICUs had a "sub-intensive unit".

MEASUREMENTS AND MAIN RESULTS

391 patients (29.9%) aneurysms and arteriovenous malformations, 25.1% tumours, 2.8% head injuries, 8.7% spontaneous intracranial haematomas, 13.5% various pathologies) were studied. Out of them 358 had an acute brain failure. 16.5% died during brain failure and 83.5% reached neurological stability within 3 days. When neurological stability was reached 32.1% of patients could be classified as "intensive", 63.6% as "intermediate" and 4.3% as "unintensive". In the four ICUs, without sub-intensive ward facilities, 361 patients were admitted with a total amount of 2292 days of hospitalization. Among them 61.9% were spent for a) patients with no brain injury (32 pts/113 days), b) postoperative patients (113 pts/167 days), c) patients in stable neurological conditions (159 pts/1139 days). Therefore, only 38% of the days recorded were given to patients that needed neurointensive care.

CONCLUSION

Out data suggest that the receptivity for acute injured patients could be increased creating recovery room units and intermediate post-intensive units together with a better interchange between general and neurosurgical ICUs.

Magnetic resonance imaging of cerebral fat embolism: a case report

Fat embolism syndrome (FES) is one of the most important causes of morbidity and mortality following multiple fractures. Neurological involvement (cerebral fat embolism) has been reported frequently. A case of cerebral fat embolism is reported. While CT scan revealed no abnormalities, MRI, performed in this patient 8 days after trauma, showed relative low-intensity areas on T1-weighted images and high intensity areas on T2-weighted images involving cerebral white matter, corpus callosum and basal ganglia. MRI follow-up (1 and 3 months post-trauma) showed nearly complete resolution of the abnormal signal. MRI seems to be a useful diagnostic tool for detecting and quantifying lesions in fat embolism syndrome.