Resolution of brain edema in severe brain injury at controlled high and low intracranial pressures

Brain motion and volume transmission: Keeping the interstice flowing

Human brain undergoes two different kinds of movements: subtle pulsatile ones associated with the cardiac cycle and others of a greater magnitude related to breathing activity. These motions constitute a pumping force for the circulation of cerebrospinal fluid (CSF). Moreover, brain motion (BM) plays a fundamental role as a driving force for the interstitial and CSF flow of tracers. We hypothesize that BM is more than a mere consequence of cardiac and respiratory activities; that it would be part of a fundamental physiological mechanism by propelling the interstitial flow of messengers, a mechanism also known as 'non-synaptic transmission' or 'volume transmission' (VT). Intracranial hypertension (ICH), a frequent complication of severe head trauma, is related to brain stiffness. Under this circumstance, not only brain perfusion could be at risk, but BM could be engaged as well. Decompressive craniectomy, presently indicated to reduce ICH refractory to medical treatment, could play a role in helping BM and VT. Once brain swelling is overcome, the closure of the cranial bone defect would ensure the recovery of the spatial and temporal patterns of BM. We discuss evidence supportive of the necessary role of a minimal and sequential BM for an adequate VT.

Automated intracranial pressure-controlled cerebrospinal fluid external drainage with LiquoGuard

INTRODUCTION

LiquoGuard is a new device for intracranial pressure (ICP)-controlled drainage of cerebrospinal fluid (CSF). This present study evaluates the accuracy of ICP measurement via the LiquoGuard device in comparison with Spiegelberg. Thus, we compared data ascertained from simultaneous measurement of ICP using tip-transducer and tip-sensor devices.

MATERIAL AND METHODS

A total of 1,764 monitoring hours in 15 patients (range, 52-219 h) were analysed. All patients received an intraventricular Spiegelberg III probe with the drainage catheter connected to the LiquoGuard system. ICP reading of both devices was performed on an hourly basis. Statistical analysis was done by applying Pearson correlation and Wilcoxon-matched pair test (p < 0.05).

RESULTS

Mean ICP values were 11 ± 5 mmHg (Spiegelberg) and 10 ± 7 mmHg (LiquoGuard); the values measured with both devices correlated well (p = 0.001; Pearson correlation =0.349; n = 1,764). In two of the 15 patients with slit ventricles, episodes of significant differences in measured values could be observed. Both patients suffering from slit ventricles failed to produce reliable measurement with the external transducer of the LiquoGuard.

CONCLUSIONS

LiquoGuard is a valuable new device for ICP-controlled CSF drainage. However, LiquoGuard tends to provide misleading results in slit ventricles. Thus, before these drawbacks are further analysed, the authors recommend additional ICP measurement with internal tip-sensor devices to avoid dangerous erroneous interpretation of ICP data.

Continuous ventricular cerebrospinal fluid drainage with intracranial pressure monitoring for management of posttraumatic diffuse brain swelling

BACKGROUND: Ventricular drainage has played an important role in the management of traumatic brain-injured patients. The aim of the present study was describe outcomes in a series of 57 patients with diffuse brain swelling underwent to intracranial pressure (ICP) monitoring. METHOD: Fifty-eight patients with diffuse posttraumatic brain swelling, were evaluated prospectively. The Glasgow Coma Scale (GCS) scores of patients varied from 4 to 12. Patients groups divided according to GCS and age. Patient neurological assessment was classified as favorable, unfavorable, and death. RESULTS: Mechanisms of injury were vehicle accidents in 72.4% and falls in 15.6%. 54% of patients had GCS scores between 6 and 8. There were no statistical differences, regarding outcome, between groups separated by age. In the adults group (n=47), 44.7% evolved favorably. CONCLUSION: Our results indicate a poor prognosis in patients with brain swelling. We believe that continuous ventricular CSF drainage with ICP monitoring is a simple method as an adjunct in the management of these patients.

Associations between cerebrospinal fluid protein concentrations, serum albumin concentrations and intracranial pressure in neurotrauma and intracranial haemorrhage

Recent evidence suggests that using intravenous isotonic albumin solution for haemodynamic resuscitation in neurotrauma is associated with adverse outcomes. This study assessed the correlations between cerebrospinal fluid protein concentrations, serum albumin concentrations and intracranial pressure in a cohort of neurosurgical patients. After obtaining ethics committee approval, correlations between concomitant cerebrospinal fluid protein concentrations, serum albumin concentrations and the mean daily intracranial pressure of 63 consecutive neurosurgical patients, grouped as neurotrauma or intracranial haemorrhage, admitted between 1 January and 31 December 2007, were assessed. The mean daily intracranial pressure was significantly associated with cerebrospinal fluid protein concentrations (Spearman correlation coefficient [SCC] = 0.496, P = 0.001), white cell counts (SCC = 0.359, P = 0.001), red cell counts (SCC = 0.399, P = .0O01) and serum albumin concentrations (SCC = 0.431, P = 0.001) in patients with neurotrauma (n=23). Cerebrospinal fluid protein concentrations were also significantly associated with concomitant serum albumin concentrations (SCC = 0.393, P = 0.001) in these patients. In patients with intracranial haemorrhage (n=40), the mean daily intracranial pressure was only significantly associated with cerebrospinal fluid white cell and red cell counts but not cerebrospinal fluid protein and serum albumin concentrations. In summary, intracranial pressure is correlated with cerebrospinal fluid protein and serum albumin concentrations in patients with severe neurotrauma, and these suggest that blood-brain barrier may not be completely intact after severe neurotrauma.

Treatment of intracranial hypertension

PURPOSE OF REVIEW

The review provides key points and recent advances regarding the treatments of intracranial hypertension as a consequence of traumatic brain injury. The review is based on the pathophysiology of brain edema and draws on the current literature as well as clinical bedside experience.

RECENT FINDINGS

The review will cite baseline literature and discuss emerging data on cerebral perfusion pressure, sedation, hypothermia, osmotherapy and albumin as treatments of intracranial hypertension in traumatic brain-injured patients.

SUMMARY

One of the key issues is to consider that traumatic brain injury is more likely a syndrome than a disease. In particular, the presence or absence of a high contusional volume could influence the treatments to be implemented. The use of osmotherapy and/or high cerebral perfusion pressure should be restricted to patients without major contusions. Some physiopathological, experimental and clinical data, however, show that corticosteroids and albumin--therapies that have been proven deleterious if administered systematically--are worth reconsidering for this subgroup of patients. The current Pitié-Salpêtrière algorithm, where treatments are stratified according to their potential side effects, will be added at the end of the review as an example of an integrated strategy.

[Management of severe traumatic brain injury]

Severe brain injuries, most often occurring in young subjects, are a major source of lost work years. These injuries are medical and surgical emergencies. Prehospital management of severe brain injuries requires intubation and mechanical ventilation aimed at normal arterial carbon dioxide pressure. Signs of transtentorial herniation: Uni- or bilateral mydriasis requires immediate perfusion of 20% mannitol or hypertonic sodium chloride. Neurological disorders after head injury justify emergency cerebral computed tomography. The presence of a mass syndrome or signs of transtentorial herniation are in principle indications for surgery. Specialized hospital management is essential. In the case of refractory intracranial hypertension, the cerebral perfusion pressure and osmotherapy should be adapted to the volume of the cerebral contusion. The use of deep hypothermia and barbiturates should be minimized as much as possible. Magnetic resonance imaging makes it possible to identify the cerebral lesions.

Hydrocephalus--revision of its definition and classification with special reference to "intractable infantile hydrocephalus"

With the advent of computed tomography (CT) scan, much information has been obtained about the pathophysiology of hydrocephalus. It is now clear that hydrocephalus is not a disease entity but rather a syndrome or sign resulting from disturbances in the dynamics of cerebralspinal fluid (CSF) caused by various diseases. Consequently, it has become necessary to revise its definition and classification. In this paper, a contemporary definition and classification of hydrocephalus are presented. Also, a classification of "intractable hydrocephalus"--with its diagnostic criteria--which is a clinically unsolved problem, is attempted, bearing in mind its place in the clinical management and future investigation of the pathophysiology of hydrocephalus.

Brain resuscitation and protection

No drug that is used for brain protection after global brain ischaemia as a result of cardiac arrest has been shown to be of benefit. Barbiturate agents have been proved not to be beneficial whereas studies of calcium-channel blocking drugs are inconclusive. Hypothermia, haemodilution and mechanical hyperventilation are not of proven benefit. Immediate defibrillation with rapid restoration of blood pressure is the best method to improve the neurological outcome after a cardiac arrest. After severe head injury, prompt emergency care to restore ventilation, oxygenation and blood pressure improves the neurological outcome. The early evacuation of extracerebral intracranial haematomas also improves the outcome. Corticosteroid therapy does not improve the outcome. The monitoring of intracranial pressure and the control of increased intracranial pressure by hyperventilation, cerebrospinal-fluid drainage and mannitol, frusemide and barbiturate therapy appear to improve the outcome after a severe head injury, although this has not been proved by randomized controlled studies.

Cerebrospinal fluid production in subarachnoid haemorrhage

Eight patients with subarachnoid and/or intraventricular haemorrhage underwent continuous extraventricular drainage and cerebrospinal fluid production was estimated by modified open drainage. The patients were in Hunt & Hess grades 2-5 on admission. Drainage was instituted within 24 h after the last bleeding episode in seven patients and the duration of drainage was 3-37 days. The median amount of CSF that was drained in 24 h was 210 ml. CSF production rate was 0.10-0.55 ml/min (median 0.28 ml/min) and there was a great variation within as well as between patients. Thus there was a trend towards a reduction in CSF production compared to reported normal values for CSF production. Three of six surviving patients required a shunt. The possible role of reduction in CSF production rate in the modification of intracranial hypertension and hydrocephalus after subarachnoid haemorrhage is discussed.

Creatine kinase BB in blood as index of prognosis and effect of treatment after severe head injury

High concentrations of creatine kinase BB (CK-BB) were found in all blood samples drawn within 6 hours of accident from 45 patients with brain contusion. The highest concentrations of more than 100 microg/l were measured in blood samples taken shortly after the accident from patients with a Glasgow Coma Score (GCS) of 6 or less. The CK-BB concentrations decreased rapidly to normal within 36 hours of accident in the patients given intensive care guided by intracranial pressure (ICP) monitoring. In patients with less severe injuries according to GCS the initial CK-BB concentrations were generally lower and normalized less rapidly. The outcome after 6 months was moderate or good in all 9 patients who had this rapid normalization of blood CK-BB. On the other hand, of 20 patients who had a more slow CK-BB decrease, only 9 had an acceptable outcome. Delayed ICP increase to more than 40 mm Hg and even delayed brain tamponade did not result in CK-BB levels higher than 5 microg/l. Brain tamponade in the acute stage resulted in rapid CK-BB decrease in the blood. In paired simultaneously drawn samples of lumbar cerebrospinal fluid (CSF) and blood, CK-BB levels were generally higher in the CSF.