Posttraumatic cerebral hemispheric swelling. Analysis of 55 cases studied with computerized tomography

Incidence, risk factors, and clinical outcomes of acute brain swelling associated with traumatic acute subdural hematoma: a retrospective study utilizing novel diagnostic criteria

Background

Post-traumatic acute brain swelling (ABS) is a major cause of elevated intracranial pressure and thus mortality. The current definition of post-traumatic ABS has certain limitations, and there is limited information available regarding ABS associated with traumatic acute subdural hematoma (ASDH).

Objectives

To investigate the incidence, risk factors, and clinical outcomes of ABS associated with traumatic ASDH.

Design

Retrospective study.

Methods

Data for 161 patients diagnosed with traumatic ASDH were retrospectively collected. Novel computed tomography-based criteria were proposed for diagnosing ABS in patients with ASDH and determining its incidence. Univariate and multivariate logistic regression analyses were performed to explore the risk factors of post-traumatic ABS. The Glasgow Outcome Scale (GOS) score, mortality, and functional prognosis of all patients at discharge and the proportion of intraoperative malignant brain bulge in surgical patients were taken as clinical outcome measures.

Results

A total of 45 (28%) patients experienced post-traumatic ABS, exhibiting significantly lower Glasgow Coma Scale scores on admission (p < 0.001). The incidence of hemispheric and whole-brain swelling was 8.1% and 19.9%, respectively. Risk factors independently associated with post-traumatic ABS were: (1) age [odds ratio (OR) = 0.917, p < 0.001]; (2) platelet to white blood cell ratio (PWR) (OR = 0.887, p = 0.012); and (3) traumatic subarachnoid hemorrhage (SAH) (OR = 4.346, p = 0.005). The ABS cohort had a lower GOS score [2 (1-3) versus 4 (3-5); p < 0.001], higher mortality (46.7% versus 6.9%; p < 0.001), and higher proportion of unfavorable functional prognosis (75.6% versus 34.5%; p < 0.001) upon discharge compared to the no ABS cohort, along with higher proportion of intraoperative malignant brain bulge (43.8% versus 0%; p < 0.001).

Conclusion

The incidence of ABS associated with ASDH is significantly high overall. Patients with ASDH who have young age, low PWR, and traumatic SAH are at an increased risk of developing post-traumatic ABS, and therefore of poor clinical outcomes.

Application of Transcranial Sonography for the Assessment of Brain Midline Shift in Patients Presenting With Suspected Intracranial Pathology to the Emergency Department of a Tertiary Care Hospital in Central Gujarat, India

BACKGROUND

A shift in midline brain structure indicates raised intracranial pressure (ICP), thereby a sign of compromised perfusion to brain tissues or a mass effect. Early diagnosis can help in planning timely neurosurgical interventions that could prevent further neuron loss. Also, this may aid in neuroprognostication.

OBJECTIVES

The objectives of the study were to find the accuracy of bedside assessment of brain midline shift (MLS) using transcranial sonography (TCS) in comparison to a computed tomography (CT) scan of the brain for patients presenting with suspected intracranial pathology to the emergency department (ED).

METHODS

This prospective observational study was carried out for one year in an ED. A total of 124 patients with suspected intracranial pathology were included in the study. Transtemporal scanning along the orbitomeatal line was performed to image the third ventricle. The distance between the third ventricle and the internal side of the temporal bone was measured on both sides as A and B. The MLS was then calculated using the following formula: midline shift = (A-B)/2. The data were entered and analyzed using a Microsoft Excel worksheet (Microsoft Corp., Redmond, WA).

RESULTS

Out of the total 124 patients enrolled in this study, adequate views for 12 patients were not obtained and, hence, they were excluded from the study. The time to perform a TCS assessment of brain MLS was around 22 minutes (range: 15-30 minutes). In our study, out of 112 analyzed patients, 33 (29.5% of our study) had a significant MLS in the brain (defined by an MLS of more than 5 mm) diagnosed by TCS. Analyzing CT brain results revealed that out of the total 112 patients under study, 27 had a significant brain MLS (24.1% of the total population under study) as defined above.

CONCLUSION

A TCS is a promising alternative to a brain CT in an emergency for brain MLS detection.

Brain Midline Shift Measurement and Its Automation: A Review of Techniques and Algorithms

Midline shift (MLS) of the brain is an important feature that can be measured using various imaging modalities including X-ray, ultrasound, computed tomography, and magnetic resonance imaging. Shift of midline intracranial structures helps diagnosing intracranial lesions, especially traumatic brain injury, stroke, brain tumor, and abscess. Being a sign of increased intracranial pressure, MLS is also an indicator of reduced brain perfusion caused by an intracranial mass or mass effect. We review studies that used the MLS to predict outcomes of patients with intracranial mass. In some studies, the MLS was also correlated to clinical features. Automated MLS measurement algorithms have significant potentials for assisting human experts in evaluating brain images. In symmetry-based algorithms, the deformed midline is detected and its distance from the ideal midline taken as the MLS. In landmark-based ones, MLS was measured following identification of specific anatomical landmarks. To validate these algorithms, measurements using these algorithms were compared to MLS measurements made by human experts. In addition to measuring the MLS on a given imaging study, there were newer applications of MLS that included comparing multiple MLS measurement before and after treatment and developing additional features to indicate mass effect. Suggestions for future research are provided.

Early stage alterations of catecholamine and adrenocorticotropic hormone levels in posttraumatic acute diffuse brain swelling

Posttraumatic acute diffuse brain swelling (PADBS) is characterized by serious brain bulk enlargement rapidly following trauma and is a major cause of elevated intracranial pressure and thus mortality. The pathogenesis of PADBS is not clearly understood, and the early stage alterations of catecholamine (CA) and adrenocorticotropic hormone (ACTH) levels in PADBS also remain largely unknown. The objective of this study was to investigate CA and ACTH levels in the patients with PADBS in the early stage and discuss the possible roles CA and ACTH in the pathogenesis of PADBS. It is a cross-sectional study. A group of patients with PADBS (n=10) was compared with a group of patients with severe brain injury (SBI) (n=33). A control group of healthy adults (n=25) was also included. Blood samples were obtained to measure levels of epinephrine (EPI), norepinephrine (NE), dopamine (DA), and ACTH as soon as the patients arrived at the neurosurgery department, which was done within 4h after trauma. Both SBI and PADBS groups of patients had higher levels of EPI, NE, DA, and ACTH than the control group. The PADBS group had significantly higher levels of EPI, NE, and ACTH than the SBI group. CA and ACTH levels are significantly increased in early stage PADBS. These results imply that CA and ACTH may play important roles in the pathogenesis of PADBS. To eliminate the effects of CA and ACTH at the early stage, and thereby protect the hypothalamus and brain stem, might be critical measures for treating patients with PADBS.

Global monitoring in the neurocritical care unit

Effective methods of monitoring the status of patients with neurological injuries began with non-invasive observations and evolved during the past several decades to include more invasive monitoring tools and physiologic measures. The monitoring paradigm continues to evolve, this time back toward the use of less invasive tools. In parallel, the science of monitoring began with the global assessment of the patient's neurological condition, evolved to focus on regional monitoring techniques, and with the advent of enhanced computing capabilities is now moving back to focus on global monitoring. The purpose of this session of the Second Neurocritical Care Research Conference was to collaboratively develop a comprehensive understanding of the state of the science for global brain monitoring and to identify research priorities for intracranial pressure monitoring, neuroimaging, and neuro-electrophysiology monitoring.

Gradual and controlled decompression for brain swelling due to severe head injury

Patients suffering from uncontrollable intracranial hypertension due to posttraumatic brain swelling (BS) generally either die or survive in an extremely disabled state. Decompressive craniectomy (DC) with dural augmentation may be the best method to assist these patients. However, the efficacy of DC on functional outcomes remains controversial. One of the factors contributing to poor outcomes could be intraoperative brain extrusion, which is an acute potential complication of DC. The authors have adopted a new surgical technique for traumatic BS that can prevent and control massive intraoperative BS (IOS). In the past 3 years, the authors have used a unique technique, called "gradual and controlled decompression", in the treatment of posttraumatic BS. This procedure consists of creating numerous small dural openings and removing clots; enlarging fenestration in the frontal and temporal basal regions to detect and treat brain contusion; making U-shaped, discontinuous, small dural incisions around the circumference of the craniotomy; and performing an augmentation duraplasty through the discontinuous small opening with dural prosthetic substances. This technique has been employed in 23 patients suffering from posttraumatic BS. In all cases, IOS was prevented and controlled through gradual stepwise decompression, and expanded duraplasty was performed successfully. This new surgical approach for posttraumatic BS can prevent severe extrusion of the brain through the craniotomy defect and allows the gradual and gentle release of the subdural space. Further clinical studies should be conducted to estimate the impact of this new technique on morbidity and mortality rates.

Neuroanatomical predictors of awakening in acutely comatose patients

OBJECTIVE

Lateral brain displacement has been associated with loss of consciousness and poor outcome in a range of acute neurologic disorders. We studied the association between lateral brain displacement and awakening from acute coma.

METHODS

This prospective observational study included all new onset coma patients admitted to the Neurosciences Critical Care Unit (NCCU) over 12 consecutive months. Head computed tomography (CT) scans were analyzed independently at coma onset, after awakening, and at follow-up. Primary outcome measure was awakening, defined as the ability to follow commands before hospital discharge. Secondary outcome measures were discharge Glasgow Coma Scale (GCS), modified Rankin Scale, Glasgow Outcome Scale, and hospital and NCCU lengths of stay.

RESULTS

Of the 85 patients studied, the mean age was 58 ± 16 years, 51% were female, and 78% had cerebrovascular etiology of coma. Fifty-one percent of patients had midline shift on head CT at coma onset and 43 (51%) patients awakened. In a multivariate analysis, independent predictors of awakening were younger age (odds ratio [OR] = 1.039, 95% confidence interval [CI] = 1.002-1.079, p = 0.040), higher GCS score at coma onset (OR = 1.455, 95% CI = 1.157-1.831, p = 0.001), nontraumatic coma etiology (OR = 4.464, 95% CI = 1.011-19.608, p = 0.048), lesser pineal shift on follow-up CT (OR = 1.316, 95% CI = 1.073-1.615, p = 0.009), and reduction or no increase in pineal shift on follow-up CT (OR = 11.628, 95% CI = 2.207-62.500, p = 0.004).

INTERPRETATION

Reversal and/or limitation of lateral brain displacement are associated with acute awakening in comatose patients. These findings suggest objective parameters to guide prognosis and treatment in patients with acute onset of coma.

Pathophysiology and clinical management of moderate and severe traumatic brain injury in the ICU

Moderate and severe traumatic brain injury (TBI) is the leading cause of morbidity and mortality among young individuals in high-income countries. Its pathophysiology is divided into two major phases: the initial neuronal injury (or primary injury) followed by secondary insults (secondary injury). Multimodality monitoring now offers neurointensivists the ability to monitor multiple physiologic parameters that act as surrogates of brain ischemia and hypoxia, the major driving forces behind secondary brain injury. The heterogeneity of the pathophysiology of TBI makes it necessary to take into consideration these interacting physiologic factors when recommending for or against any therapies; it may also account for the failure of all the neuroprotective therapies studied so far. In this review, the authors focus on neuroclinicians and neurointensivists, and discuss the developments in therapeutic strategies aimed at optimizing intracranial pressure and cerebral perfusion pressure, and minimizing cerebral hypoxia. The management of moderate to severe TBI in the intensive care unit is moving away from a pure "threshold-based" treatment approach toward consideration of patient-specific characteristics, including the state of cerebral autoregulation. The authors also include a concise discussion on the management of medical and neurologic complications peculiar to TBI as well as an overview of prognostication.

Role of coagulopathy in patients with head trauma

Coagulation disorders are a well known complication in patients with head injuries. A prospective study was undertaken to determine the incidence and prognostic value of haemostatic abnormalities in this group of patients. Clotting mechanisms in 105 patients with an isolated head injury were evaluated using platelet count (PC), prothrombin time (PT), activated partial thromboplastin time (APPT), thrombin clotting time (TCT), plasma fibrinogen concentration (Fib), level of fibrin-fibrinogen degradation products (FDP) and increased consumptive coagulopathy grade (ICCG) in the first 24 h after injury. The clinical severity of the head injuries was represented by the post-resuscitation Glasgow coma score (GCS) divided into four coma groups (CG). Test results were compared between two outcome groups of patients: discharged and dead. The incidence of disseminated intravascular coagulation (DIC) by laboratory criteria in the two groups was 12% and 38%, respectively. The differences between mean values of the discharged and dead patients for GCS, APTT, FDP and ICCG were statistically significant (P < 0.001). There was a very strong correlation between the GCS and values of the FDP, APTT, TCT and ICCG (P < 0.01). Stepwise logistic regression analysis demonstrated that GCS, FDP level, and ICCG predicted outcome in 84% of cases. Other tests did not provide additional predictive value. We conclude that evaluation of coagulation and fibrinolysis in patients with head injuries is not only important in identifying the occurrence of coagulopathy, but also useful in predicting head injury outcome.

Bilateral hemicraniectomy in non-penetrating traumatic brain injury

Traumatic brain injury is a heterogeneous entity that encompasses both surgical and non-surgical conditions. Surgery may be indicated with traumatic lesions such as hemorrhage, fractures, or malignant cerebral edema. However, the neurological exam may be clouded by the effects of medications administered in the field, systemic injuries, and inaccuracies in hyperacute prognostication. Typically, neurological injury is considered irreversible if diffuse loss of grey/white matter differentiation or if brainstem hemorrhage (Duret hemorrhage) exists. We aim to characterize a cohort of patients undergoing bilateral hemicraniectomy for severe traumatic brain injury. A retrospective consecutive cohort of adult patients undergoing craniectomy for trauma was established between the dates of January 2008 and November 2011. The primary outcome of the study was in-hospital mortality. Secondary outcomes were ICU length of stay, surgical complications, and Glasgow Outcome Score at most recent follow-up. During the study period, 210 patients undergoing craniectomy for traumatic mass-occupying lesion (epidural hematoma, subdural hematoma, or parenchymal contusion) were analyzed. Of those, 9 met study criteria. In-hospital mortality was 67% (6 of 9 patients). The average ICU length of stay was 12 days. The GOS score was 3 in surviving patients. Bilateral hemicraniectomy is a heroic intervention for patients with severe TBI, but can be a life-saving procedure.

Updated imaging of traumatic brain injury

Computed tomography (CT) and magnetic resonance (MR) play important roles in the evaluation of traumatic brain injury. Modern CT scanners allow for rapid and accurate diagnosis of intracranial hemorrhage and mass effect and allow the efficient implementation of emergent CT angiography. Newer sequences, such as gradient recalled echo, susceptibility-weighted imaging, and diffusion-weighted imaging, can provide greater sensitivity for specific types of diffuse posttraumatic brain injury. MR spectroscopy can provide additional chemical information, and diffusion tensor imaging can provide information about white matter injury. Patient treatment can be optimized using the diagnostic and prognostic information derived from current imaging techniques.

D-dimer as a predictor of progressive hemorrhagic injury in patients with traumatic brain injury: analysis of 194 cases

This study sought to describe and evaluate any relationship between D-dimer values and progressive hemorrhagic injury (PHI) after traumatic brain injury (TBI). In patients with TBI, plasma D-dimer was measured while a computed tomography (CT) scan was conducted as soon as the patient was admitted to the emergency department. A series of other clinical and laboratory parameters were also measured and recorded. A logistic multiple regression analysis was used to identify risk factors for PHI. A cohort of 194 patients with TBI was evaluated in this clinical study. Eighty-one (41.8%) patients suffered PHI as determined by a second CT scan. The plasma D-dimer level was higher in patients who demonstrated PHI compared with those who did not (P < 0.001. Using a receiver-operator characteristic curve to predict the possibility by measuring the D-dimer level, a value of 5.00 mg/L was considered the cutoff point, with a sensitivity of 72.8% and a specificity of 78.8%. Eight-four patients had D-dimer levels higher than the cut point value (5.0 mg/L); PHI was seen in 71.4% of these patients and in 19.1% of the other patients (P < 0.01). Factors with P < 0.2 on bivariate analysis were included in a stepwise logistic regression analysis to identify independent risk factors for TBI coagulopathy. Logistic regression analysis showed that the D-dimer value was a predictor of PHI, and the odds ratio (OR) was 1.341 with per milligram per liter (P = 0.020). The stepwise logistic regression also identified that time from injury to the first CT shorter than 2 h (OR = 2.118, P = 0.047), PLT counts lesser than 100 x 109/L (OR = 7.853, P = 0.018), and Fg lower than 2.0 g/L (OR = 3.001, P = 0.012) were risk factors for the development of PHI. When D-dimer values were dichotomized at 5 mg/L, time from injury to the first CT scan was no longer a risk factor statistically while the OR value of D-dimer to the occurrence of PHI elevated to 11.850(P < 0.001). The level of plasma D-dimer after TBI can be a useful prognostic factor for PHI and should be considered in the clinical management of patients in combination with neuroimaging and other data.

Current and evolving management of traumatic brain injury

This article discuss the pathophysiology of traumatic brain injury and increased intracranial pressure, the consequences and treatment of secondary insults, and strategies for the medical and nursing management of the patient who has traumatic brain injury.

Substance P is associated with the development of brain edema and functional deficits after traumatic brain injury

Brain edema and swelling is a critical factor in the high mortality and morbidity associated with traumatic brain injury (TBI). Despite this, the mechanisms associated with its development are poorly understood and interventions have not changed in over 30 years. Although neuropeptides and neurogenic inflammation have been implicated in peripheral edema formation, their role in the development of central nervous system edema after brain trauma has not been investigated. This study examines the role of the neuropeptide, substance P (SP), in the development of edema and functional deficits after brain trauma in rats. After severe diffuse TBI in adult male rats, neuronal and perivascular SP immunoreactivity were increased markedly. Perivascular SP colocalized with exogenously administered Evans blue, supporting a role for SP in vascular permeability. Inhibition of SP action by administration of the neurokinin-1 (NK1) antagonist, N-acetyl-L-tryptophan, at 30 mins after trauma attenuated vascular permeability and edema formation. Administration of the NK1 antagonist also improved both motor and cognitive neurologic outcomes. These findings suggest that SP release is integrally linked to the increased vascular permeability and edema formation after brain trauma, and that treatment with an NK1 receptor antagonist reduces edema and improves neurologic outcome.

The effect of haematoma, brain injury, and secondary insult on brain swelling in traumatic acute subdural haemorrhage

OBJECTIVE

The high mortality of acute subdural haematoma (ASDH) is largely explained by its frequent association with primary brain damage consisting of contusion and brain swelling. However, the nature and causes of brain swelling after traumatic brain injury are multifactorial and poorly understood. The purpose of this study was to investigate the pathophysiology of brain swelling associated with ASDH in traumatic brain injury.

METHODS

We examined whether the thickness of the haematoma, parenchymal injury, or presence of a secondary insult had an effect on traumatic brain swelling. The variables that might affect the pathophysiology of ASDH were examined, including: (1) age and mechanism of injury, (2) neurological findings, (3) secondary insult and extracranial injuries, (4) pre-operative computed tomography (CT) scan results, and (5) outcome.

RESULTS

A total of 212 patients were included in this study. On CT scan, 159 patients (75.0%) did not have brain swelling, 29 (13.7%) had hemispheric brain swelling, and 24 (11.3%) had diffuse brain swelling. Brain swelling associated with ASDH is caused by secondary insult in addition to parenchymal injury. In the present study, the outcome of ASDH associated with brain swelling was poor, even when treated with early surgical evacuation; the mortality rate of such patients was over 75%.

CONCLUSIONS

Given our findings, it is possible that the poor outcome of ASDH patients depends not only on the characteristics of the haematoma itself, but also on the presence of additional cerebral parenchymal injury and secondary insult.

Substance P in traumatic brain injury

Recent evidence has suggested that neuropeptides, and in particular substance P (SP), may play a critical role in the development of morphological injury and functional deficits following acute insults to the brain. Few studies, however, have examined the role of SP, and more generally, neurogenic inflammation, in the pathophysiology of traumatic brain injury and stroke. Those studies that have been reported suggest that SP is released following injury to the CNS and facilitates the increased permeability of the blood brain barrier, the development of vasogenic edema and the subsequent cell death and functional deficits that are associated with these events. Inhibition of the SP activity, either through inhibition of the neuropeptide release or the use of SP receptor antagonists, have consistently resulted in profound decreases in edema formation and marked improvements in functional outcome. The current review summarizes the role of SP in acute brain injury, focussing on its properties as a neurotransmitter and the potential for SP to adversely affect outcome.

Cerebral hemodynamic changes gauged by transcranial Doppler ultrasonography in patients with posttraumatic brain swelling treated by surgical decompression

Object

The use of decompressive craniectomy has experienced a revival in the previous decade, although its actual benefit on patients’ neurological outcome remains the subject of debate. A better understanding of the intracranial pressure dynamics, as well as of the metabolic and hemodynamic brain processes, may be useful in assessing the effect of this surgery on the pathophysiology of the swollen brain. The aim of this study was to use transcranial Doppler (TCD) ultrasonography to examine the hemodynamic changes in the brain after decompressive craniectomy in patients with head injury, in addition to examining the relationship between such hemodynamic changes and the patient’s neurological outcome.

Methods

Nineteen patients presenting with traumatic brain swelling and cerebral herniation syndrome who had undergone decompressive craniectomy with dural expansion were studied prospectively. The TCD ultrasonography measurements were performed bilaterally in both the middle cerebral artery (MCA) and in the distal portion of the cervical internal carotid artery (ICA) immediately prior to and after surgical decompression.

After surgery, the mean blood flow velocity (BFV) rose to 175 ± 209% of preoperative values in the MCA of the operated side, while rising to 132 ± 183% in the contralateral side; the difference between the mean BFV increase in in the MCA of both the decompressed and the opposite side reached statistical significance (p < 0.05). The mean BFV of the extracranial ICA increased to 91 ± 119% in the surgical side and 45 ± 60% in the opposite side. Conversely, the MCA pulsatility index (PI) values decreased, on average, to 33 ± 36% of the preoperative value in the operated side and to 30 ± 34% on the opposite side; the MCA PI value reductions were significantly greater in the decompressed side when compared with the contralateral side (p < 0.05). The PI of the extracranial ICA reduced, on average, to 37 ± 23% of the initial values in the operated side and to 24 ± 34%, contralaterally. No correlation was verified between the neurological outcome and cerebral hemodynamic changes seen on TCD ultrasonography.

Conclusions

Decompressive craniectomy results in a significant elevation of cerebral BFV in most patients with traumatic brain swelling and transtentorial herniation syndrome. The increase in cerebral BFV may also occur in the side opposite the decompressed hemisphere; the cerebral BFV increase is significantly greater in the operated hemisphere than contralaterally. Concomitantly, PI values decrease significantly postoperatively, mainly in the decompressed cerebral hemisphere, indicating reduction in cerebrovascular resistance.

Acute subdural hematoma associated with diffuse brain injury and hypoxemia in the rat: effect of surgical evacuation of the hematoma

The aim of this study was to assess the effect of rapid or delayed surgical evacuation on the physiological consequence and brain edema formation in a rat model of acute subdural hematoma (SDH) coupled with either diffuse brain injury (DBI) or hypoxemia. The SDH was made by an autologous blood injection, while DBI was induced using the impact acceleration model (mild, 450 g/1 m; severe, 450 g/2 m). Physiological parameters measured included intracranial pressure (ICP), mean arterial blood pressure (MABP), cerebral blood flow (CBF), and brain tissue water content. At 1 h (rapid evacuation) or 4 h (delayed evacuation) after the SDH induction, surgical evacuation following a craniotomy was performed using saline irrigation and forceps. The study consisted of three different series, including 400 microL of SDH alone (Series 1), SDH400 + mild DBI (Series 2), and SDH300 + severe DBI + 20 min hypoxemia (Series 3). The hypoxemia was added in Group 3 to produce a steadily increasing ICP. In Series 1 and 2, all rats were randomized into the three following groups: non-, rapid, and delayed evacuation; Series 3 had two groups: non- and rapid evacuation. In Series 1, the surgical evacuation showed no beneficial effects on the brain edema formation assessed at 5 h post-injury. In Series 2, the rapid, but not delayed, evacuation significantly reduced both the increased ICP level and brain water content. The additional insult of hypoxemia (Series 3) resulted in a progressive ICP elevation, persistently depressed CBF, and severe brain swelling. Under this situation, the rapid evacuation exacerbated brain edema. These results have clinical implications for the management of severe traumatic SDH, especially its operative indication and timing.

Risk factors for intraoperative hypotension in traumatic intracranial hematoma

Patients suffering from traumatic intracranial hemorrhage (TICH) may experience an episode of catastrophic intraoperative hypotension (IHT), after decompression of the brain. The aim of this study was to investigate the risk factors for IHT during emergency craniotomy A total of 67 patients, who underwent emergency craniotomy due to TICH, were divided into two groups: IHT ( n=31 ) or without IHT ( n=36 ). Data concerning (1) age; (2) gender; (3) mechanism of injury; (4) Glasgow Coma Scale (GCS) on admission; (5) abnormality of the pupils (anisocoria or mydriasis); (6) mean arterial blood pressure; (7) heart rate; (8) time elapsed before craniotomy from injury; (9) initial brain CT scans; (10) duration of craniotomy; and (11) total infusion or urine volume until craniotomy were collected prospectively as IHT risk factors. Low GCS score (<5), tachycardia (heart rate >112min(-1)) and hypertension (mean blood pressure >131mmHg) before emergency craniotomy were strongly ( P<0.05 ) associated with IHT. Delayed surgery (>173min until craniotomy) also had a significant ( P<0.005 ) effect on IHT. The risk factors for IHT were considered as a low GCS score on admission, tachycardia, hypertension before emergency craniotomy and delayed surgery. These results suggested the patients with IHT had a high sympathetic tone before emergency craniotomy A sudden reduction in sympathetic tone after surgical decompression of the brain might cause IHT. We concluded that an important factor in the occurrence of IHT was not only the injury severity, but also the balance between sympathetic and parasympathetic activity before decompression surgery.

Chronic cognitive effects of bilateral subdural haematomas in the rat

Humans suffering from subdural haematomas often show long-term cognitive dysfunctions. For identifying putative, recovery-enhancing therapeutics, animal models need to be developed in which recovery of function can be measured. For investigating whether and which type of recovery, i.e. spontaneous or training-induced recovery, or continuous partial retardation, is present in the rat model for bilateral subdural haematomas, spatial navigation abilities were assessed in the Morris water escape task in independent groups of rats at 1, 2, 4, 8, or 18 weeks after surgery. Complete spontaneous recovery seemed to occur at 8 weeks after injury. However, at 18 weeks after injury, the subdural haematoma caused a renewed deterioration of water maze performance, which was of a lesser degree than the impairments observed immediately after injury. This second phase performance deterioration was accompanied by an increase in generalised astrocyte reactivity. The rat subdural haematoma model provides an interesting tool for investigating spontaneous recovery processes of spatial navigation (8 weeks after injury), but also for progressive brain dysfunctions, considering the second phase of behavioural impairments seen at 18 weeks after injury.

A new rat model of diffuse brain injury associated with acute subdural hematoma: assessment of varying hematoma volume, insult severity, and the presence of hypoxemia

The aim of this study was to develop a new rat model of diffuse brain injury (DBI) associated with acute subdural hemorrhage (SDH). In order to make this model more clinically relevant, we determined whether the varying hematoma volume, severity of DBI, or the presence of hypoxemia could influence the physiological consequence. SDH was made by an autologous blood injection, while DBI was induced using the impact acceleration model (mild, 450 g/1 m, severe, 450 g/2 m). Physiological parameters measured included intracranial pressure (ICP), mean arterial blood pressure (MABP), cerebral blood flow (CBF), and brain tissue water content. In the first series, 23 rats were randomized into the five following groups: Group 1, sham; Group 2, 400 (microL SDH; Group 3, SDH400 + mild DBI; Group 4, SDH400 + severe DBI; and Group 5, SDH300 + severe DBI. Results suggested that SDH300 + severe DBI (Group 5) may be the most suitable model, in which the MABP and CBF temporarily decreased during the SDH induction, but thereafter recovered to the baseline. Conversely, ICP was persistently elevated throughout the experiment. The water content was also significantly higher in both hemispheres compared to that of sham. In the second series, the animal was exposed to a hypoxemic insult (10 or 30 min) in addition to SDH300 + severe DBI (Group 6). The prolonged hypoxemia caused both a severe CBF reduction without recovery and a bilateral brain swelling, whereas the brief hypoxemia showed a gradual CBF recovery from the transient reduction and an increased water content only in the SDH side. These results suggest that these models may be potentially useful to study the combination of DBI and SDH with or without hypoxemia.

Analysis of ischemic brain damage in cases of acute subdural hematomas

BACKGROUND

Ischemic damage of the brain is one of the most important factors for the sequelae of acute subdural hematomas (ASDHs). However, ischemic damage is infrequently addressed in a systematic manner in the clinical setting.

METHODS

The analysis of ischemic brain damage was performed based on serial computed tomography (CT) scans in 80 patients with traumatic ASDHs. Single photon emission computed tomography (SPECT) for regional blood flow and/or magnetic resonance imaging (MRI) were also performed.

RESULTS

Follow-up CT scans showed ischemic brain damage in 19 patients and no significant damage in 35 patients. The remaining 26 patients progressively deteriorated to the point of brain death. The ischemic brain damage was seen most frequently in the territory of the anterior cerebral artery (13 cases), followed by the territory of the posterior cerebral artery (12 cases). The ischemic damages in the pallidum, the hypothalamus and the thalamus were demonstrated in 4, 8, and 4 cases, respectively. The ischemic damage in the underlying brain that was probably because of the direct compression of the hematoma was seen in only two cases.

CONCLUSIONS

Most of the ischemic brain damage noted in this study was because of arterial compression secondary to the brain shift and brain herniation, rather than the direct effect of the hematoma upon the underlying brain. Ischemic brain damage adversely affects outcome morbidity, and the difficulty in preventing ischemic damage in cases with marked brain shift leads to poor outcome in patients with ASDHs.

Effect of early induction of hypothermia on severe head injury

Although therapeutic hypothermia for patients with head injury has improved the outcome, the results in the most severe cases (GCS 3-6) have not been satisfactory so far. We induced hypothermia in head injury patients within 3 hours after the trauma, and compared the outcome of the treatment without hypothermia. Fourteen patients with GCS less than 6 were entered into this study (age range 13 to 58, mean 27.0 years). Seven of them were treated by hypothermia and 6 by the conventional method. The patients undergoing hypothermia were cooled to 34 degrees C within 3 hours after injury, kept at 32-34 degrees C for 48 hours, and then rewarmed. The outcome was evaluated at 6 months post-trauma, and the results were compared in the two groups. Therapeutic hypothermia dramatically suppressed brain swelling on CT in 3 of 7 patients. Four patients including these 3 showed a favorable outcome (good or moderate disability) and 3 died in the hypothermia group. In the conventional treatment group, only 1 patient was moderately disabled and 6 exhibited an unfavorable outcome (severely disabled, vegetative, or death). Early induction of hypothermia can improve the outcome in patients with severe head injury by reducing the severe brain swelling.

Diffuse brain injury complicated by acute subdural hematoma and secondary insults in the rodents: the effect of surgical evacuation

Head Trauma associated with acute sudural hematoma (SDH) and complicated by secondary insult is a grave clinical combination with complex pathophysiology. The aim of this study was to develop a clinically relevant injury model, which can be used to study the interaction between injury mechanisms. We present a novel model of SDH combined with diffuse brain injury (DBI) and a hypoxic secondary insult, and investigate the effects of surgical evacuation. Adult Sprague-Dawley rats were given a 300 microliters SDH and 20 minute-hypoxia following Impact Acceleration DBI. Hematoma was evacuated at one hour post-injury. Physiological parameters were measured for 5 hours, together with assessment of brain water content. Secondary insult after traumatic SDH was associated with significant brain swelling and stimulated refractory rise in ICP. In traumatic SDH complicated by secondary insult, brain swelling is exacerbated by surgical evacuation.

Intercommunications between brain capillary endothelial cells and glial cells increase the transcellular permeability of the blood-brain barrier during ischaemia

Increased cerebrovascular permeability is an important factor in the development of cerebral oedema after stroke, implicating the blood-brain barrier (BBB). To investigate the effect of hypoxia on the permeability changes, we used a cell culture model of the BBB consisting of a co-culture of brain capillary endothelial cells and glial cells. When endothelial cells from this co-culture model were submitted alone to hypoxic conditions, long exposures (48 h) were necessary to result in an increase in endothelial cell monolayer permeability to [3H]inulin. When endothelial cells were incubated in presence of glial cells, a huge increase in permeability occurred after 9 h of hypoxic conditions. Oxygen glucose deprivation (OGD) resulted in a much shorter time (i.e. 2 h) required for an increase in permeability. We have demonstrated that this OGD-induced permeability increase involves a transcellular rather than a paracellular pathway. Conditioned medium experiments showed that glial cells secrete soluble permeability factors during OGD. However, endothelial cells have to be made sensitive by OGD in order to respond to these glial soluble factors. This work shows that an early cross-talk between glial and endothelial cells occurs during ischaemic stroke and alters BBB transcellular transport by means of glial factor secretions.

Influence of inspired oxygen on glucose-lactate dynamics after subdural hematoma in the rat

The mechanisms causing brain damage after acute subdural hematoma (SDH) are poorly understood. A decrease in cerebral blood flow develops immediately after the hematoma forms, thus reducing cerebral oxygenation. This in turn may activate mitochondrial failure and tissue damage leading to ionic imbalance and possibly to cellular breakdown. The purpose of this study was to test whether a simple therapeutic measure, namely increased fraction of inspired oxygen (FiO2 100), and hence increased arterial and brain tissue oxygen tension, can influence brain glucose and lactate dynamics acutely after subdural hematoma in the rat. Twenty-five male Sprague-Dawley anesthetized rats were studied before, during and after induction of the SDH in two separate groups. The Oxygen group (n = 10) was ventilated with 100% oxygen immediately after induction of the SDH. The Air group (n = 10) was ventilated during the entire study with 21% oxygen. Brain microdialysate samples were analyzed for glucose and lactate. All rats were monitored with femoral arterial blood pressure catheters, arterial blood gas analysis, arterial glucose, lactate and end tidal CO2 (EtCO2). Five male Sprague-Dawley rats were sham operated to measure the effect of oxygen challenge on glucose-lactate dynamics without injury. Arterial oxygen tension in the Oxygen group was 371 +/- 30 mmHg and was associated with significantly greater increase in dialysate lactate in the first 30 min after induction of SDH. Dialysate glucose initially dropped in both groups, after SDH, but then reverted significantly faster to values above baseline in the Oxygen group. Changes in ventilatory parameters had no significant effect on dialysate glucose and lactate parameters in the sham group. Extracellular dialysate lactate and glucose are influenced by administration of 100% O2 after SDH. Dialysate glucose normalizes significantly quicker upon 100% oxygen ventilation. We hypothesize that increased neural tissue oxygen tension, in presence of reduced regional CBF, and possibly compromised mitochondrial function, after acute SDH results in upregulation of rate-limiting enzyme systems responsible for both glycolytic and aerobic metabolism. Similar changes have been seen in severe human head injury, and suggest that a simple therapeutic measure, such as early ventilation with 100% O2, may improve cerebral energy metabolism, early after SDH. Further studies to measure the generation of adenosine triphosphate (ATP) are needed to validate the hypothesis.

Calcium/calmodulin-modulated chloride and taurine conductances in cultured rat astrocytes

Osmotically swollen rat cerebral astrocytes develop an increased anion conductance which can mediate chloride and taurine release. We used whole cell patch clamp to study mechanisms that modulate this conductance. Astrocyte chloride conductance increased within 4 min of exposure to 200 mOsm medium and was 670+/-123% of its initial value after 15 min (mean+/-S.E.M.). This conductance was substantially reduced in 0.1 mM extracellular calcium with 20 mM BAPTA added to the electrode solution and was completely inhibited with calcium-free perfusion solution containing 1 mM EDTA (n=4). The conductance increase in 200 mOsm medium also was inhibited in a dose-dependent manner by nimodipine with a calculated K(i) of 0.31+/-0.4 microM and mean+/-S.E.M. inhibition of 84.4+/-4% at 100 microM nimodipine. In the presence of 100 microM W-7, a calmodulin antagonist, the mean+/-S.E.M. conductance increase after 15 min was 223+/-40% of the initial value while 300 microM W-7 or 100 microM trifluoperazine inhibited the conductance increase completely (n=6). With taurine as the major anion in electrode and perfusion solutions, a significant conductance increase was observed in 200 mOsm medium. This conductance increase was inhibited by 300 microM W-7 or 100 microM nimodipine. We conclude extracellular calcium influx via L-type calcium channels leads to increased astrocyte anion conductance in 200 mOsm conditions via calmodulin-dependent activation of anion channels. Efflux of anionic taurine from swollen astrocytes also may be affected by calcium influx through a similar calcium/calmodulin-dependent process.

Integrated Plastic Microfluidic Devices with ESI-MS for Drug Screening and Residue Analysis

For this work, two different plastic microfluidic devices are designed and fabricated for applications in high-throughput residue analysis of food contaminants and drug screening of small-molecule libraries. Microfluidic networks on copolyester and poly(dimethylsiloxane) substrates are fabricated by silicon template imprinting and capillary molding techniques. The first device is developed to perform affinity capture, concentration, and direct identification of targeted compounds using electrospray ionization mass spectrometry. Poly(vinylidene fluoride) membranes sandwiched between the imprinted copolyester microchannels in an integrated platform provide continuous affinity dialysis and concentration of a reaction mixture containing aflatoxin B1 antibody and aflatoxins. The second microfluidic device is composed of microchannels on the poly(dimethylsiloxane) substrates. The device is designed to perform miniaturized ultrafiltration of affinity complexes of phenobarbital antibody and barbiturates, including the sequential loading, washing, and dissociation steps. These microfabricated devices not only significantly reduce dead volume and sample consumption but also increase the detection sensitivity by at least 1-2 orders of magnitude over those reported previously. Improvements in detection sensitivity are attributed to analyte preconcentration during the affinity purification step, limited analyte dilution in the microdialysis junction, minimal sample loss, and the amenability of ESI-MS to nanoscale sample flow rates.

Neurological recovery from closed head injury is impaired in diabetic rats

Diabetes mellitus is a metabolic disorder associated with central nervous system impairments. Recent studies implicate oxidative stress mediated by reactive oxygen species (ROS) in the pathogenesis of diabetic complications. ROS have been shown to play role in the pathophysiology of brain injury. In the present study, closed head injury (CHI) was induced in diabetic rats to test the hypothesis that chronic oxidative stress exacerbates brain damage following CHI. Neurological recovery, edema, levels of low molecular weight antioxidants (LMWA), and markers of lipid peroxidation were determined at different intervals after injury. Diabetic rats (4 weeks after induction with streptozotocin) were subjected to CHI. Brain edema (percent water) and clinical status (neurological severity score) were assessed during 7 days. Brain LMWA were determined using cyclic voltammetry (CV) and HPLC-EC. In addition, conjugated dienes and thiobarbituric acid reactive substances (TBARS) were measured. Diabetic-CHI rats exhibited a lower rate of recovery and greater and more sustained edema (p < 0.01), as compared with the controls. At all times diabetic rats had higher levels of TBARS and conjugated dienes and lower concentrations of LMWA, and of vitamins C and E, suggesting chronic oxidative stress. At 5 min of CHI, the amounts of LMWA in control-CHI brains decreased (approximately 50%, p < 0.01) and returned to normal by 48 h and 7 days. In the diabetic-CHI brain only one class of LMWA slightly declined but remained low for 7 days. The present results support the hypothesis that diabetic rats are under chronic oxidative stress, and suffer greater neurological dysfunction, associated with further lipid peroxidation following CHI.

The Brain Trauma Foundation. The American Association of Neurological Surgeons. The Joint Section on Neurotrauma and Critical Care. Hypotension

Hypotension, occurring at any time from injury through the acute intensive care course, has been found to be a primary predictor of outcome from severe head injury for the health care delivery systems within which prognostic variables have been best studied. Hypotension is repeatedly found to be one of the five most powerful predictors of outcome and is generally the only one of these five that is amenable to therapeutic modification. A single recording of a hypotensive episode is generally associated with a doubling of mortality and a marked increase in morbidity from a given head injury. The estimated reduction in unfavorable outcome that would result from the elimination of hypotensive secondary brain insults is profound.

The Brain Trauma Foundation. The American Association of Neurological Surgeons. The Joint Section on Neurotrauma and Critical Care. Use of barbiturates in the control of intracranial hypertension

High-dose barbiturate therapy is efficacious in lowering ICP and decreasing mortality in the setting of uncontrollable ICP refractory to all other conventional medical and surgical ICP-lowering treatments. Utilization of barbiturates for the prophylactic treatment of ICP is not indicated. The potential complications attendant on this form of therapy mandate that its use be limited to critical care providers and that appropriate systemic monitoring be undertaken to avoid or treat any hemodynamic instability. When barbiturate coma is utilized, consideration should also be given to monitoring arteriovenous oxygen saturation as some patients treated in this fashion may develop oligemic cerebral hypoxia.

[Congestive brain swelling in victims of fatal road accident. Frequency and association with other head injury lesions]

A morphological study, macro and microscopical, was made of brain lesions in 120 victims of fatal road traffic accidents. Congestive brain swelling occurred in 21 (17.5%) patients. Owing to the brain swelling that increases the brain volume, an increase of brain weight was also observed. Brain contusion was the most frequent lesion associated with congestive brain swelling (76.2%), while the intracranial haematomas were observed in almost half of the cases.

Severe head injury in children: impact of risk factors on outcome

BACKGROUND

Outcome after severe head injury has been shown in some studies to be more favorable in children than in adults. Mortality rates reported range between 20% and 40% for children. Only contradicting data are available regarding the impact of trauma modalities on long-term outcome, or the relative influence of head fractures, intracranial hemorrhages, and brain edema on survival or neurologic sequelae in children.

METHODS

A retrospective study in a tertiary care facility of long-term outcome of children after severe head injury, and analysis of risk factors for poor outcome. All children up to 16 years of age with severe head injury (Glasgow Coma Scale [GCS] score < or = 8), which have been treated in the pediatric intensive care unit from 1977 until 1994 in a single institution.

RESULTS

A total of 150 children with severe head injury (GCS score < or = 8) were treated, 92 of them (61.3%) had traffic-related injuries. The median age was 6.6 years (SD +/- 3.6). There were 96 boys (64%) and 54 girls (36%). Sixty-five children (43.3%) had skull fractures, 87 patients (58.0%) developed an intracranial hemorrhage, and 79 patients (52.7%) developed a diffuse brain swelling/edema visible in computed tomographic scans within 72 hours after trauma. Of 150 children treated, 33 died (22%). In most cases, death was related to the development of secondary brain edema. Fifty-nine children (39.3%) had severe neurologic impairments at the time of discharge. The most significant risk factors for adverse outcome, shown by multivariate analysis, were primary areflexia and secondary brain edema. The risk for development of brain edema and poor prognosis was well predicted by the GCS score.

CONCLUSION

The overall death rate in this study of children with severe head injury was low (22%) compared with other studies. However, the incidence of severe neurologic impairment at discharge remained high. The major risks for death or neurologic impairment were primary areflexia and the development of secondary brain swelling/edema, indicated by a low GCS score.

Neuroprotective effect of rasagiline, a selective monoamine oxidase-B inhibitor, against closed head injury in the mouse

The potential neuroprotective effects of rasagiline, N-propargyl-1R-aminoindan, a selective monoamine oxidase-B inhibitor and its inactive enantiomer TVP 1022, N-propargyl-1S-aminoindan were assessed against the sequelae of closed head injury in the mouse. Injury was induced in the left hemisphere under ether anaesthesia. Rasagiline (0.2 and 1 mg/kg) or TVP1022 (1 and 2 mg/kg) injected 5 min after injury accelerated the recovery of motor function and spatial memory and reduced the cerebral oedema by about 40-50%, (P < 0.01). The neuroprotective effects on motor function and spatial memory, but not on cerebral oedema, were prevented by scopolamine (0.2 mg/kg). Daily injection of rasagiline (1 mg/kg) from day 3 after injury accelerated the recovery of spatial memory but not motor function.

CONCLUSIONS

Early administration of rasagiline or TVP1022 can reduce the immediate sequelae of brain injury. The mechanism of action does not appear to involve monoamine oxidase-B inhibition but could be mediated by the maintenance of cholinergic transmission in brain neurons.

[Is the metabolic response self-limited in head trauma? Analysis of acute phase proteins and glycemia]

There are many reports supporting a self-limitation mechanism involved with hypermetabolic response after severe cranial injury. It was proposed a study with severe head injury patients, in three stages of the evolution. The first 7 days after admission (moment 1-M1), the second three days latter (M2) and the last 7 days after the first (M3). Among male patients with severe head injury, attended between January 1992 and December 1993 in University Hospital of Botucatu, UNESP, were selected 28 male patients, with Glasgow severity scale between 4 and 6, with pO2 < 70 mm Hg, weighting 60 kg or more. Among these patients, 6 finished the study, including analysis of the excretion of N, acute phase proteins, glycemia, triglycerides and amine nitrogen. During the study there were no changes in nitrogen balance and there was a decrease in protein C-reative. Glycemia tends to fall within two weeks after injury. The authors make some considerations about possible mechanisms involved in brain modulation associated with the period of dependence of hypermetabolism and hypercatabolism after closed brain injury. There are some evidences that the brain responds to head trauma with a gobal non specific way, which tends to be reorganized beyond the first two weeks after lesion. The study does not show any influence of the type and severity of head trauma.

Origin of chronic subdural haematoma and relation to traumatic subdural lesions

The origin of chronic subdural haematoma (CSDH) and the pathogenesis of subdural hygroma (SDG) are still controversial issues. These issues and relationships between these traumatic subdural lesions are discussed. The origin of CSDH is usually a SDG, although a few cases are caused by acute subdural haematomas (ASDH). Subdural hygroma is produced by separation of the dura-arachnoid interface, when there is sufficient subdural space. When the brain remains shrunken, the SDG remains unresolved. Any pathologic condition inducing cleavage of tissue within the dural border layer at the dura-arachnoid interface can induce proliferation of dural border cells with production of neomembrane. In-growth of new vessels will follow, especially along the outer membrane, then bleeding from these vessels occurs. These unresolved SDGs become CSDHs by repeated microhaemorrhage from the neomembrane. Although most victims with ASDH underwent surgery or died, some patients could be managed conservatively. Since the ASDH is usually absorbed within a few weeks, only a very few ASDHs become CSDHs, when there is a sufficient potential subdural space. Chronic subdural haematoma can arise from ASDH, but more commonly from SDG. Such transformation, or development of a new subdural lesion, is a function of the premorbid status and the dynamics of absorption and expansion.

Pathogenesis of traumatic brain swelling: role of cerebral blood volume

The pathogenesis of traumatic brain swelling is unclear. Brain edema (increased water content) is considered an important cause of swelling, but there is also evidence that vasodilatation with increased cerebral blood volume (CBV) plays a role. We have evaluated early posttraumatic changes in CBV in 37 head-injured patients, using dynamic contrast-enhanced computerized tomography (CT) in combination with stable Xenon-enhanced CT for measurement of cerebral blood flow (CBF). This technique enables rapid determination of CBV without interfering with patient care. CBV values ranged from 2.0 to 10.1 ml/100 g. There was no relationship the time after injury at which the measurements were taken. CBV did not correlate with CBF in the early posttraumatic period. Patients with raised ICP (> 20 mm Hg) had significantly higher CBV that patients with normal ICP (5.4 +/- 2.1 vs 3.7 +/- 0.9 ml/100 g). Yet, the presence of signs of brain swelling on CT had no relation to the level of CBV. These data suggest that increased CBV may contribute to raised ICP, but that brain swelling is not caused by increased CBV alone, and is more likely accounted for by brain edema. We speculate that cerebral energy failure is the unifying cause of both intracellular edema and cerebral vasodilation leading to swelling of brain tissue.

Selection of severely head injured patients for mild hypothermia therapy

OBJECT

The authors have analyzed the efficacy of inducing mild hypothermia (34 degrees C) in 62 severely head injured patients to control fulminant intracranial hypertension.

METHODS

All 62 patients fulfilled the following criteria: 1)persistent intracranial pressure (ICP) greater than 20 mm Hg despite fluid restriction, hyperventilation, and high-dose barbiturate therapy; 2) an ICP lower than the mean arterial pressure; and 3) a Glasgow Coma Scale (GCS) score of 8 or less on admission. The patients were divided into three groups based on computerized tomography findings: extracerebral hematoma (34 patients with subdural and/or epidural hematoma), focal cerebral lesion (20 patients with localized brain contusion and/or intracerebral hematoma), and diffuse swelling (eight patients with no focal mass lesion). Mild hypothermia prevented ICP elevation in 35 (56.5%) of the 62 patients whose ICP was greater than 20 mm Hg despite conventional therapies. Among those 35 patients whose ICP was controlled by mild hypothermia, 12 (34.3%) achieved functional recovery (good outcome or moderate disability). However, functional recovery was observed in only five (10.9%) of the 46 patients whose ICP was greater than 40 mm Hg after conventional therapies. Of 40 patients with an admission GCS score of 5 to 8, there were 11 (27.5%) who achieved functional recovery. On the contrary, mild hypothermia was not effective in 22 patients with an admission GCS score of 3 or 4. In the patients with focal cerebral lesions, ICP was controlled by mild hypothermia in 17 patients (85%) and patient outcome was intimately related to the extent of the damage. Among 18 patients with extracerebral hematoma who had a midline shift of 9 to 12 mm, raised ICP could be successfully controlled by mild hypothermia in 16 patients (88.9%) and three (16.7%) achieved functional recovery. However, ICP could not be controlled in patients with extracerebral hematoma who had a midline shift of 13 mm or more. In patients with diffuse swelling, ICP elevation could not be prevented at all by mild hypothermia.

CONCLUSIONS

The authors conclude that mild hypothermia is effective for preventing ICP elevation in patients without diffuse brain swelling in whom ICP remains higher than 20 mm Hg but less than 40 mm Hg after conventional therapies.

Rivastigmine, a brain-selective acetylcholinesterase inhibitor, ameliorates cognitive and motor deficits induced by closed-head injury in the mouse

The effects of Rivastigmine, a novel centrally-acting anticholinesterase agent, were evaluated on cerebral edema, neurological and motor deficits, and impairment of spatial memory induced in mice by closed-head injury (CHI). Severe injury was induced in the left hemisphere of mice under ether anesthesia. Rivastigmine (1 or 2 mg/kg) or saline (10 ml/kg) was injected SC 5 min later. Rivastigmine (2 mg/kg) reduced cerebral edema by at least 50% (p < 0.01), 24 h after CHI and accelerated the recovery of motor function 7 and 14 days after CHI. Control mice (n = 24), previously trained to find the goal platform in a Morris water maze failed to recall or relearn its position for at least 11 days post-injury. Those given a single injection of Rivastigmine (2 mg/kg) regained their pre-test latencies by the third day after CHI. The neuroprotective effects of Rivastigmine on brain edema, neurological and motor function, and performance in the Morris water maze were completely antagonized by simultaneous SC injection of either scopolamine (0.5 mg/kg) or mecamylamine (2.5 mg/kg). The antagonists alone had no significant effect on any of these parameters. These data show that the reduction by Rivastigmine of the immediate and long-term sequelae of brain injury are mediated by increased cholinergic activity at both muscarinic and nicotinic receptors.

Cerebro-protective effects of ENA713, a novel acetylcholinesterase inhibitor, in closed head injury in the rat

Focal ischemic brain damage and diffuse brain swelling occur in severe cases of traumatic head injury. Ischemia decreases brain acetylcholine (ACh) levels and head trauma upregulates acetylcholinesterase (AChE) in experimental animal models. The present study determined whether a brain-selective AChE inhibitor, ENA713, given once, up to 2 h after closed head injury (CHI) could reduce the vasogenic edema and accelerate recovery from neurological deficits induced by the injury in rats. ENA713 1-5 mg/kg produced a dose-related inhibition of AChE ranging from 40-85% in the cortex and hippocampus. Doses of 1, 2 and 5 mg/kg, significantly reduced the motor and neurological deficits and speeded recovery, as indicated by measurements made 7 and 14 days after injury. The two larger doses were still effective when injected 1 or 2 h after CHI. The acceleration by ENA713 of recovery of motor function was independent of its reduction in body temperature and was prevented by the simultaneous injection of mecamylamine (2.5 mg/kg), but not by scopolamine (0.2 or 1 mg/kg). Edema in the contused hemisphere (24 h after injury) and disruption of the blood brain barrier (4 h after injury) were significantly reduced (about 50%) by doses of 2 and 5 mg/kg, but not by 1 mg/kg. The data support the hypothesis that ENA713 exerts a neuroprotective effect in brain injury by preventing the decrease in cholinergic activity in cerebral vessels and in neurones.

Acute posttraumatic subdural hematomas: "intradural" computed tomographic appearance as a favorable prognostic factor

OBJECTIVE

Posttraumatic acute subdural hematoma carries a high postoperative mortality rate. Preservation of subarachnoid spaces in preoperative computed tomographic (CT) scans may be interpreted as a favorable prognostic factor.

METHODS

Thirty-one cases of posttraumatic acute subdural hematoma operated on consecutively, with an interval from trauma to surgery of less than 4 hours and a Glasgow Coma Scale score of less than 8, were reviewed. The immediate and long-term results were evaluated with reference to preoperative CT images, distinguishing cases with preserved subarachnoid spaces from the others.

RESULTS

In 5 of the 31 cases, preoperative CT scans showed intact subarachnoid spaces and the absence of blood in the cerebrospinal fluid. These cases presented a much better postoperative course than did the others.

CONCLUSION

The presence of intact subarachnoid spaces in CT scans for patients with acute subdural hematomas may be interpreted as an extremely favorable prognostic factor; this may be attributed to the protective effect of the integral visceral membrane of the hematoma, which prevents the diffusion of neurotoxic and vasoactive substances into the subarachnoid spaces. This group of hematomas was classified as "intradural," with reference to the concept of the "subdural compartment" described in studies conducted using an electron microscope.