Long-term observations of intracranial pressure after severe head injury. The phenomenon of secondary rise of intracranial pressure

Effects of increased intracranial pressure on cerebrospinal fluid influx, cerebral vascular hemodynamic indexes, and cerebrospinal fluid lymphatic efflux

The glymphatic-lymphatic fluid transport system (GLFTS) consists of glymphatic pathway and cerebrospinal fluid (CSF) lymphatic outflow routes, allowing biological liquids from the brain parenchyma to access the CSF along with perivascular space and to be cleaned out of the skull through lymphatic vessels. It is known that increased local pressure due to physical compression of tissue improves lymphatic transport in peripheral organs, but little is known about the exact relationship between increased intracranial pressure (IICP) and GLFTS. In this study, we verify our hypothesis that IICP significantly impacts GLFTS, and this effect depends on severity of the IICP. Using a previously developed inflating balloon model to induce IICP and inject fluorescent tracers into the cisterna magna, we found significant impairment of the glymphatic circulation after IICP. We further found that cerebrovascular occlusion occurred, and cerebrovascular pulsation decreased after IICP. IICP also interrupted the drainage of deep cervical lymph nodes and dorsal meningeal lymphatic function, enhancing spinal lymphatic outflow to the sacral lymph nodes. Notably, these effects were associated with the severity of IICP. Thus, our findings proved that the intensity of IICP significantly impacts GLFTS. This may have translational applications for preventing and treating related neurological disorders.

A 12-Year Audit of Neurological Outcomes Associated with Core Body Temperature >37.5°C in Children with Severe Traumatic Brain Injury

Hyperthermia exposure is associated with poor neurological outcomes in patients with severe traumatic brain injury (TBI). Our aim was to describe fever in children with severe TBI admitted to a pediatric intensive care unit (PICU) for at least 72 hours and to evaluate associations between fever using a novel approach to describe thermal exposure and neurobehavioral outcomes. The cohort included children from birth to 17 years of age admitted to the PICU between 2000 and 2012 for at least 72 hours who had severe TBI with intracranial pressure monitoring. Patients with non-accidental TBI or pre-existing developmental delays were excluded. Hyperthermia was defined as a core temperature >37.5°C. Hourly temperature measurements were used to calculate the area under the curve (AUC) using the linear trapezoidal rule. Each participant was followed up at the Brain Injury Clinic 6 and 18 months postinjury. Neurobehavioral outcome scores were analyzed against AUC using standard statistical methods. Ninety-eight patients admitted with severe TBI met the study inclusion criteria. Hyperthermia/fever was common (89.7%), and patients remained hyperthermic for a median of 9.4 hours. However, no statistically significant association was found between AUC and abnormal neurological outcomes. The follow-up rates were good at 6 (86.7%) and 18 months (83.7%). The neurological deficit improved with time, with "favorable outcomes" increasing from 72% to 94% at the respective follow-up months. Our study used a novel method to describe patients' fever, providing a different indicator of thermal exposure than that previously reported. In addition, the AUC was well correlated with the maximum temperature recorded and the proportion of time >37.5°C, indicating that it is a good surrogate for thermal exposure. Interestingly, the neurological disabilities of the patients improved over time.

Intracranial Pressure Trajectories: A Novel Approach to Informing Severe Traumatic Brain Injury Phenotypes

OBJECTIVES

Intracranial pressure in traumatic brain injury is dynamic and influenced by factors like injury patterns, treatments, and genetics. Existing studies use time invariant summary intracranial pressure measures thus potentially losing critical information about temporal trends. We identified longitudinal intracranial pressure trajectories in severe traumatic brain injury and evaluated whether they predicted outcome. We further interrogated the model to explore whether ABCC8 polymorphisms (a known cerebraledema regulator) differed across trajectory groups.

DESIGN

Prospective observational cohort.

SETTING

Single-center academic medical center.

PATIENTS

Four-hundred four severe traumatic brain injury patients.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We used group-based trajectory modeling to identify hourly intracranial pressure trajectories in days 0-5 post traumatic brain injury incorporating risk factor adjustment (age, sex, Glasgow Coma Scale 6score, craniectomy, primary hemorrhage pattern). We compared 6-month outcomes (Glasgow Outcome Scale, Disability Rating Scale, mortality) and ABCC8 tag-single-nucleotide polymorphisms associated with cerebral edema (rs2237982, rs7105832) across groups. Regression models determined whether trajectory groups predicted outcome. A six trajectory group model best fit the data, identifying cohorts differing in initial intracranial pressure, evolution, and number/proportion of spikes greater than 20 mm Hg. There were pattern differences in age, hemorrhage type, and craniectomy rates. ABCC8 polymorphisms differed across groups. GOS (p = 0.006), Disability Rating Scale (p = 0.001), mortality (p < 0.0001), and rs2237982 (p = 0.035) differed across groups. Unfavorable outcomes were surprisingly predicted by both low intracranial pressure trajectories and sustained intracranial hypertension. Intracranial pressure variability differed across groups (p < 0.001) and may reflect preserved/impaired intracranial elastance/compliance.

CONCLUSIONS

We employed a novel approach investigating longitudinal/dynamic intracranial pressure patterns in traumatic brain injury. In a risk adjusted model, six groups were identified and predicted outcomes. If validated, trajectory modeling may be a first step toward developing a new, granular approach for intracranial pressure phenotyping in conjunction with other phenotyping tools like biomarkers and neuroimaging. This may be particularly relevant in light of changing traumatic brain injury demographics toward the elderly.

Changes in Posttraumatic Brain Edema in Craniectomy-Selective Brain Hypothermia Model Are Associated With Modulation of Aquaporin-4 Level

Both hypothermia and decompressive craniectomy have been considered as a treatment for traumatic brain injury. In previous experiments we established a murine model of decompressive craniectomy and we presented attenuated edema formation due to focal brain cooling. Since edema development is regulated via function of water channel proteins, our hypothesis was that the effects of decompressive craniectomy and of hypothermia are associated with a change in aquaporin-4 (AQP4) concentration. Male CD-1 mice were assigned into following groups (n = 5): sham, decompressive craniectomy, trauma, trauma followed by decompressive craniectomy and trauma + decompressive craniectomy followed by focal hypothermia. After 24 h, magnetic resonance imaging with volumetric evaluation of edema and contusion were performed, followed by ELISA analysis of AQP4 concentration in brain homogenates. Additional histopathological analysis of AQP4 immunoreactivity has been performed at more remote time point of 28d. Correlation analysis revealed a relationship between AQP4 level and both volume of edema (r² = 0.45, p < 0.01, ^**) and contusion (r² = 0.41, p < 0.01, ^**) 24 h after injury. Aggregated analysis of AQP4 level (mean ± SEM) presented increased AQP4 concentration in animals subjected to trauma and decompressive craniectomy (52.1 ± 5.2 pg/mL, p = 0.01; ^*), but not to trauma, decompressive craniectomy and hypothermia (45.3 ± 3.6 pg/mL, p > 0.05; ns) as compared with animals subjected to decompressive craniectomy only (32.8 ± 2.4 pg/mL). However, semiquantitative histopathological analysis at remote time point revealed no significant difference in AQP4 immunoreactivity across the experimental groups. This suggests that AQP4 is involved in early stages of brain edema formation after surgical decompression. The protective effect of selective brain cooling may be related to change in AQP4 response after decompressive craniectomy. The therapeutic potential of this interaction should be further explored.

Treatment of Hyponatremia in Patients with Acute Neurological Injury

BACKGROUND

Little data exist regarding the practice of sodium management in acute neurologically injured patients. This study describes the practice variations, thresholds for treatment, and effectiveness of treatment in this population.

METHODS

This retrospective, multicenter, observational study identified 400 ICU patients, from 17 centers, admitted for ≥48 h with subarachnoid hemorrhage (SAH), traumatic brain injury (TBI), intraparenchymal hemorrhage, or intracranial tumors between January 1, 2011 and July 31, 2012. Data collection included demographics, APACHE II, Glascow Coma Score (GCS), serum sodium (Na+), fluid rate and tonicity, use of sodium-altering therapies, intensive care unit (ICU) and hospital length of stay, and modified Rankin score upon discharge. Data were collected for the first 21 days of ICU admission or ICU discharge, whichever came first. Sodium trigger for treatment defined as the Na+ value prior to treatment with response defined as an increase of ≥4 mEq/L at 24 h.

RESULTS

Sodium-altering therapy was initiated in 34 % (137/400) of patients with 23 % (32/137) having Na⁺ >135 mEq/L at time of treatment initiation. The most common indications for treatment were declining serum Na⁺ (68/116, 59 %) and cerebral edema with mental status changes (21/116, 18 %). Median Na⁺ treatment trigger was 133 mEq/L (IQR 129-139) with no difference between diagnoses. Incidence and treatment of hyponatremia was more common in SAH and TBI [SAH (49/106, 46 %), TBI (39/97, 40 %), ICH (27/102, 26 %), tumor (22/95, 23 %); p = 0.001]. The most common initial treatment was hypertonic saline (85/137, 62 %), followed by oral sodium chloride tablets (42/137, 31 %) and fluid restriction (15/137, 11 %). Among treated patients, 60 % had a response at 24 h. Treated patients had lower admission GCS (12 vs. 14, p = 0.02) and higher APACHE II scores (12 vs. 10, p = 0.001). There was no statistically significant difference in outcome when comparing treated and untreated patients.

CONCLUSION

Sodium-altering therapy is commonly employed among neurologically injured patients. Hypertonic saline infusions were used first line in more than half of treated patients with the majority having a positive response at 24 h. Further studies are needed to evaluate the impact of various treatments on patient outcomes.

White matter damage after traumatic brain injury: A role for damage associated molecular patterns

Traumatic brain injury (TBI) is a leading cause of mortality and long-term morbidity worldwide. Despite decades of pre-clinical investigation, therapeutic strategies focused on acute neuroprotection failed to improve TBI outcomes. This lack of translational success has necessitated a reassessment of the optimal targets for intervention, including a heightened focus on secondary injury mechanisms. Chronic immune activation correlates with progressive neurodegeneration for decades after TBI; however, significant challenges remain in functionally and mechanistically defining immune activation after TBI. In this review, we explore the burgeoning evidence implicating the acute release of damage associated molecular patterns (DAMPs), such as adenosine 5'-triphosphate (ATP), high mobility group box protein 1 (HMGB1), S100 proteins, and hyaluronic acid in the initiation of progressive neurological injury, including white matter loss after TBI. The role that pattern recognition receptors, including toll-like receptor and purinergic receptors, play in progressive neurological injury after TBI is detailed. Finally, we provide support for the notion that resident and infiltrating macrophages are critical cellular targets linking acute DAMP release with adaptive immune responses and chronic injury after TBI. The therapeutic potential of targeting DAMPs and barriers to clinical translational, in the context of TBI patient management, are discussed.

Tracheostomy risk factors and outcomes after severe traumatic brain injury

OBJECTIVE

To determine risk factors associated with tracheostomy placement after severe traumatic brain injury (TBI) and subsequent outcomes among those who did and did not receive a tracheostomy.

METHODS

This retrospective cohort study compared adult trauma patients with severe TBI (n = 583) who did and did not receive tracheostomy. A multivariable logistic regression model assessed the associations between age, sex, race, insurance status, admission GCS, AIS (Head, Face, Chest) and tracheostomy placement. Ordinal logistic regression models assessed tracheostomy's influence on ventilator days and ICU LOS. To limit immortal time bias, Cox proportional hazards models assessed mortality at 1, 3 and 12-months.

RESULTS

In this multivariable model, younger age and private insurance were associated with increased probability of tracheostomy. AIS, ISS, GCS, race and sex were not risk factors for tracheostomy placement. Age showed a non-linear relationship with tracheostomy placement; likelihood peaked in the fourth decade and declined with age. Compared to uninsured patients, privately insured patients had an increased probability of receiving a tracheostomy (OR = 1.89 [95% CI = 1.09-3.23]). Mortality was higher in those without tracheostomy placement (HR = 4.92 [95% CI = 3.49-6.93]). Abbreviated injury scale-Head was an independent factor for time to death (HR = 2.53 [95% CI = 2.00-3.19]), but age, gender and insurance were not.

CONCLUSIONS

Age and insurance status are independently associated with tracheostomy placement, but not with mortality after severe TBI. Tracheostomy placement is associated with increased survival after severe TBI.

Multivariate projection method to investigate inflammation associated with secondary insults and outcome after human traumatic brain injury: a pilot study

BACKGROUND

Neuroinflammation has been proposed as a possible mechanism of brain damage after traumatic brain injury (TBI), but no consensus has been reached on the most relevant molecules. Furthermore, secondary insults occurring after TBI contribute to worsen neurological outcome in addition to the primary injury. We hypothesized that after TBI, a specific pattern of cytokines is related to secondary insults and outcome.

METHODS

A prospective observational clinical study was performed. Secondary insults by computerized multimodality monitoring system and systemic value of different cytokines were collected and analysed in the first week after intensive care unit admission. Neurological outcome was assessed at 6 months (GOSe). Multivariate projection technique was applied to analyse major sources of variation and collinearity within the cytokines dataset without a priori selecting potential relevant molecules.

RESULTS

Twenty-nine severe traumatic brain injury patients undergoing intracranial pressure monitoring were studied. In this pilot study, we demonstrated that after TBI, patients who suffered of prolonged and severe secondary brain damage are characterised by a specific pattern of cytokines. Patients evolving to brain death exhibited higher levels of inflammatory mediators compared to both patients with favorable and unfavorable neurological outcome at 6 months. Raised ICP and low cerebral perfusion pressure occurred in 21 % of good monitoring time. Furthermore, the principal components selected by multivariate projection technique were powerful predictors of neurological outcome.

CONCLUSIONS

The multivariate projection method represents a valuable methodology to study neuroinflammation pattern occurring after secondary brain damage in severe TBI patients, overcoming multiple putative interactions between mediators and avoiding any subjective selection of relevant molecules.

The use of targeted temperature management for elevated intracranial pressure

The use of hypothermia for treatment of intracranial hypertension is controversial, despite no other medical therapy demonstrating consistent improvements in morbidity or mortality. Much of this may be the result of negative results from randomized controlled trials. However, the patients selected for these trials may have obscured the results in the populations most likely to benefit. Further, brain injury does not behave uniformly, not even within a diagnosis. Therefore, therapies may have more benefit in some diseases, less in others. This review focuses on the effect on outcome of intracranial hypertension in common disease processes in the neurocritical care unit, and identifies who is most likely to benefit from the use of hypothermia.

Hyponatremia in Patients with Spontaneous Intracerebral Hemorrhage

Hyponatremia is the most frequently encountered electrolyte abnormality in critically ill patients. Hyponatremia on admission has been identified as an independent predictor of in-hospital mortality in patients with spontaneous intracerebral hemorrhage (sICH). However, the incidence and etiology of hyponatremia (HN) during hospitalization in a neurointensive care unit following spontaneous intracerebral hemorrhage (sICH) remains unknown. This was a retrospective analysis of consecutive patients admitted to Detroit Receiving Hospital for sICH between January 2006 and July 2009. All serum Na levels were recorded for patients during the ICU stay. HN was defined as Na <135 mmol/L. A total of 99 patients were analyzed with HN developing in 24% of sICH patients. Patients with HN had an average sodium nadir of 130 ± 3 mmol/L and an average time from admission to sodium <135 mmol/L of 3.9 ± 5.7 days. The most common cause of hyponatremia was syndrome of inappropriate antidiuretic hormone (90% of HN patients). Patients with HN were more likely to have fever (50% vs. 23%; p = 0.01), infection (58% vs. 28%; p = 0.007) as well as a longer hospital length of stay (14 (8–25) vs. 6 (3–9) days; p < 0.001). Of the patients who developed HN, fifteen (62.5%) patients developed HN in the first week following sICH. This shows HN has a fairly high incidence following sICH. The presence of HN is associated with longer hospital length of stays and higher rates of patient complications, which may result in worse patient outcomes. Further study is necessary to characterize the clinical relevance and treatment of HN in this population.

Capillary transit time heterogeneity and flow-metabolism coupling after traumatic brain injury

Most patients who die after traumatic brain injury (TBI) show evidence of ischemic brain damage. Nevertheless, it has proven difficult to demonstrate cerebral ischemia in TBI patients. After TBI, both global and localized changes in cerebral blood flow (CBF) are observed, depending on the extent of diffuse brain swelling and the size and location of contusions and hematoma. These changes vary considerably over time, with most TBI patients showing reduced CBF during the first 12 hours after injury, then hyperperfusion, and in some patients vasospasms before CBF eventually normalizes. This apparent neurovascular uncoupling has been ascribed to mitochondrial dysfunction, hindered oxygen diffusion into tissue, or microthrombosis. Capillary compression by astrocytic endfeet swelling is observed in biopsies acquired from TBI patients. In animal models, elevated intracranial pressure compresses capillaries, causing redistribution of capillary flows into patterns argued to cause functional shunting of oxygenated blood through the capillary bed. We used a biophysical model of oxygen transport in tissue to examine how capillary flow disturbances may contribute to the profound changes in CBF after TBI. The analysis suggests that elevated capillary transit time heterogeneity can cause critical reductions in oxygen availability in the absence of 'classic' ischemia. We discuss diagnostic and therapeutic consequences of these predictions.

Timing of intracranial hypertension following severe traumatic brain injury

BACKGROUND

We asked whether continuous intracranial pressure (ICP) monitoring data could provide objective measures of the degree and timing of intracranial hypertension (ICH) in the first week of neurotrauma critical care and whether such data could be linked to outcome.

METHODS

We enrolled adult (>17 years old) patients admitted to our Level I trauma center within 6 h of severe TBI. ICP data were automatically captured and ICP 5-minute means were grouped into 12-hour time periods from admission (hour 0) to >7 days (hour 180). Means, maximum, percent time (% time), and pressure-times-time dose (PTD, mmHg h) of ICP >20 mmHg and >30 mmHg were calculated for each time period.

RESULTS

From 2008 to 2010, we enrolled 191 patients. Only 2.1% had no episodes of ICH. The timing of maximum PTD20 was relatively equally distributed across the 15 time periods. Median ICP, PTD20, %time20, and %time30 were all significantly higher in the 84-180 h time period than the 0-84 h time period. Stratified by functional outcome, those with poor functional outcome had significantly more ICH in hours 84-180. Multivariate analysis revealed that, after 84 h of monitoring, every 5% increase in PTD20 was independently associated with 21% higher odds of having a poor functional outcome (adjusted odds ratio = 1.21, 95% CI 1.02-1.42, p = 0.03).

CONCLUSIONS

Although early elevations in ICP occur, ICPs are the highest later in the hospital course than previously understood, and temporal patterns of ICP elevation are associated with functional outcome. Understanding this temporal nature of secondary insults has significant implications for management.

Marked reduction in mortality in patients with severe traumatic brain injury

OBJECT

In spite of evidence that use of the Brain Trauma Foundation Guidelines for the Management of Severe Traumatic Brain Injury (Guidelines) would dramatically reduce morbidity and mortality, adherence to these Guidelines remains variable across trauma centers. The authors analyzed 2-week mortality due to severe traumatic brain injury (TBI) from 2001 through 2009 in New York State and examined the trends in adherence to the Guidelines.

METHODS

The authors calculated trends in adherence to the Guidelines and age-adjusted 2-week mortality rates between January 1, 2001, and December 31, 2009. Univariate and multivariate logistic regression analyses were performed to evaluate the effect of time period on case-fatality. Intracranial pressure (ICP) monitor insertion was modeled in a 2-level hierarchical model using generalized linear mixed effects to allow for clustering by different centers.

RESULTS

From 2001 to 2009, the case-fatality rate decreased from 22% to 13% (p < 0.0001), a change that remained significant after adjusting for factors that independently predict mortality (adjusted OR 0.52, 95% CI 0.39-0.70; p < 0.0001). Guidelines adherence increased, with the percentage of patients with ICP monitoring increasing from 56% to 75% (p < 0.0001). Adherence to cerebral perfusion pressure treatment thresholds increased from 15% to 48% (p < 0.0001). The proportion of patients having an ICP elevation greater than 25 mm Hg dropped from 42% to 29% (p = 0.0001).

CONCLUSIONS

There was a significant reduction in TBI mortality between 2001 and 2009 in New York State. Increase in Guidelines adherence occurred at the same time as the pronounced decrease in 2-week mortality and decreased rate of intracranial hypertension, suggesting a causal relationship between Guidelines adherence and improved outcomes. Our findings warrant future investigation to identify methods for increasing and sustaining adherence to evidence-based Guidelines recommendations.

The relationship between basal cisterns on CT and time-linked intracranial pressure in paediatric head injury

PURPOSE

Although intracranial pressure (ICP) monitoring is a cornerstone of care for severe traumatic brain injury (TBI), the indications for ICP monitoring in children are unclear. Often, decisions are based on head computed tomography (CT) scan characteristics. Arguably, the patency of the basal cisterns is the most commonly used of these signs. Although raised ICP is more likely with obliterated basal cisterns, the implications of open cisterns are less clear. We examined the association between the status of perimesencephalic cisterns and time-linked ICP values in paediatric severe TBI.

METHODS

ICP data linked to individual head CT scans were reviewed. Basal cisterns were classified as open or closed by blinded reviewers. For the initial CT scan, we examined ICP values for the first 6 h after monitor insertion. For follow-up scans, we examined ICP values 3 h before and after scanning. Mean ICP and any episode of ICP ≥ 20 mmHg during this period were recorded.

RESULTS

Data from 104 patients were examined. Basal cisterns were patent in 51.72% of scans, effaced in 34.48% and obliterated in 13.79%. Even when cisterns were open, more than 40% of scans had at least one episode of ICP ≥ 20 mmHg, and 14% of scans had a mean ICP ≥ 20 mmHg. The specificity of open cisterns in predicting ICP < 20 mmHg was poor (57.9%). Age-related data were worse.

CONCLUSION

Children with severe TBI frequently may have open basal cisterns on head CT despite increased ICP. Open cisterns should not discourage ICP monitoring.

Challenges of surgical trauma emergency admission

INTRODUCTION

Trauma still remains as one of the leading causes for mortality in Western civilization. The early clinical management of severely injured patients leads to structural and organizational challenges involving different specialties.

EMERGENCY DEPARTMENT

Trauma team leaders have to coordinate diagnostic and therapeutic steps in cooperation with different involved specialties. Furthermore, they have to make decisions based on contrary department-depending assessments. In addition, several special injuries commonly found in multiple traumatized patients require special attention.

RECENT DEVELOPMENT

Actually, structural changes in generating trauma networks are to be mentioned. Trauma networks suggest to improve patients survival in close cooperation between hospitals with different structural and personal capabilities. Close communication networks are required to guarantee transportation to an adequate trauma center.

Intracranial pressure monitoring for traumatic brain injury in the modern era

INTRODUCTION

Intracranial pressure (ICP) has become a cornerstone of care in adult and pediatric patients with traumatic brain injury (TBI).

DISCUSSION

Despite the fact that continuous monitoring of ICP in TBI was described almost 60 years ago, there are no randomized trials confirming the benefit of ICP monitoring and treatment in TBI. There is, however, a large body of clinical evidence showing that ICP monitoring influences treatment and leads to better outcomes if part of protocol-driven therapy. However, treatment of ICP has adverse effects, and there are several questions about ICP management that have yet to be definitively answered, particularly in pediatric TBI. This review examines the history and evolution of ICP monitoring, pathophysiological concepts that influence ICP interpretation, ongoing controversies, and the place of ICP monitoring in modern neurocritical care.

[Head injuries in children]

Trauma is the reason for 40-60% of emergency callouts concerning children. Approximately half of the children have head injuries. As for adults early recognition of findings indicating an intervention are decisive for the prognosis. In children head injury can be divided into three categories: birth trauma, accidental and non-accidental trauma. This article concentrates on accidental trauma with respect to characteristics of causes, epidemiology, mechanisms of accidents and illustrated morphological findings.

Hyponatraemia in patients with normal pressure hydrocephalus

BACKGROUND

In clinical practice, hyponatraemia was frequently found in patients with hydrocephalus. We conducted this study to determine the prevalence and risk factors for hyponatraemia in patients with normal pressure hydrocephalus (NPH).

METHODS

We retrospectively reviewed all patients with NPH who were admitted to China Medical University Hospital between 1998 and 2006. Hyponatraemia was defined as a plasma sodium concentration < 135 mEq/l on admission. Possible risk factors between patients with and without hyponatraemia were analysed using Student's t-test or chi2 test. The association between hyponatraemia and possible factors was analysed using multivariate logistic regression. The odds ratio was calculated to determine the effect of possible risk factors.

RESULTS

A total of 146 patients (84 men and 62 women) who had NPH with a mean age of 66.1 +/- 15.9 years old were reviewed and 33 (22.6%) patients were found having hyponatraemia. Patients who developed hyponatraemia had a significantly higher prevalence of hypertension, use of nasogastric tube (NG), bed-ridden status and fever. In multivariate logistic regression, the presence of hypertension and the use of NG were two important risk factors for hyponatraemia. The odds ratio (95% CI) for hypertension and NG were 2.604 (95% CI: 1.136-5.967, p = 0.024) and 7.179 (95% CI: 2.3-22.409, p = 0.001) respectively.

CONCLUSION

Hyponatraemia is not uncommon in patients with NPH. Physicians should be aware of this complication and obtain necessary laboratory examination for early detection of hyponatraemia.

Intracranial pressure monitoring during percutaneous tracheostomy "percutwist" in critically ill neurosurgery patients

BACKGROUND

Tracheostomy is commonly required as part of the management of patients with severe brain damage. Percutaneous dilation tracheostomy is increasingly used in intensive care unit as an alternative to standard surgical tracheostomy. However, this procedure carries the risk of neurological complications, particularly in patients with intracranial hypertension. In this study, we sought to quantify the effects of Percutwist(R) tracheostomy (Rusch-Teleflex Medical) on intracranial pressure (ICP), cerebral perfusion pressure (CPP), arterial CO(2) tension (Paco(2)), and arterial O(2) tension (Pao(2)), in 65 consecutive critically ill patients admitted to the neurosurgical intensive care unit, undergoing bedside percutaneous tracheostomy.

METHODS

Sixty-five patients (29 men, 36 women, mean age 43 yr, 7 +/- 10.6) Glasgow Coma Scale <or=8, requiring long-term ventilatory support with a stable ICP <or=20 mm Hg were included. Elective percutaneous tracheostomies were performed at the bedside under endoscopic fiberoptic control. Intraoperative monitoring included continuous: electrocardiogram, Spo(2), invasive arterial blood pressure, ICP, CPP = mean arterial blood pressure-ICP). Episodes of ICP increment above 20 mm Hg or CPP decrease below 60 mm Hg (lasting more than 3 min) were recorded; hypoxia was defined as Pao(2) below 90 mm Hg, hypercarbia as Paco(2) more than 40 mm Hg.

RESULTS

Eighteen episodes of intracranial hypertension were recorded in 11 patients. No statistically significant modification of monitored variables was recorded, although the transient ICP increase was very close to statistical significance (P = 0.051). No episodes of CPP reduction below 60 mm Hg occurred. Six percent of patients developed hypercarbia.

CONCLUSIONS

Percutwist tracheostomy is a single-step method which allows for effective ventilation during the procedure, thus reducing the risk of hypercarbia and development of intracranial hypertension. The technique did not cause secondary pathophysiological insult and could be considered safe in a selected population of brain-injured patients.

Patterns of increased intracranial pressure after severe traumatic brain injury

INTRODUCTION

Secondary brain injury due to increased intracranial pressure (ICP) contributes to post-traumatic morbidity and mortality. Although it is often taught that increased ICP begins early after traumatic brain injury, some patients develop increased ICP after the first 3 days post-injury. We examined our data to describe temporal patterns of increased ICP.

METHODS

This is a retrospective review of prospectively collected physiologic and demographic data.

RESULTS

Seventy-seven patients were included. We identified four patterns of increased ICP: beginning within 72 h (early), beginning after 72 h (late), early increases with resolution, and then a second rise after 72 h (bimodal), and continuously increased ICP. Late increases in ICP occur in 17% of this cohort. Peak day of swelling was day 7 for the "late" rise group and day 4 for the other patients with increased ICP. Forty-four percent of patients showed enlargement of cerebral contusions on follow-up imaging at 24 h post-injury.

CONCLUSIONS

Late rises in ICP were not rare in this cohort. This is clinically relevant as it may impact decisions about ICP monitor removal. Differences between groups in age, CT patterns of injury, fluid therapy, osmotic use, and fever were not statistically significant.

Analysis of intracranial pressure changes during early versus late percutaneous tracheostomy in a neuro-intensive care unit

BACKGROUND

We aimed to investigate intracranial pressure (ICP) changes during early versus late bedside percutaneous tracheostomy (PT) in a neuro-intensive care unit (NICU).

METHODS

This study included 30 patients admitted to our NICU for head trauma, subarachnoid haemorrhage, intracerebral haematoma or brain tumour with a Glasgow Coma Score (GCS) less than 8. These patients also underwent ICP monitoring. Bedside PT was performed either early (within 7 days of ventilation) or late (after 7 days of ventilation) via the Griggs system. In all patients; ICP, systemic blood pressure, heart rate, oxygen saturation (Sat O(2)) and arterial blood gases were recorded 5 min before the procedure, during skin incision, during tracheal cannulation, as well as 5 min and 10 min after the procedure.

FINDINGS

Thirty patients, 18 male and 12 female, with various intracranial pathologies between ages 18 and 78 (mean 38.7 +/- 20) were identified. The admission GCS ranged between 4 and 11 (median 7). Physiological variables did not differ significantly between the two groups. In the early group, ICP values measured 5 min before the procedure, during skin incision, during tracheal cannulation, as well as 5 min and 10 min after the procedure were 15.1 +/- 5.2, 22 +/- 10.1, 28.4 +/- 13.7, 17.3 +/- 7.1, 13.8 +/- 5.0 mmHg, respectively. In the late group, these values were 14.2 +/- 4.5, 17.2 +/- 5.5, 21.5 +/- 8.0, 15.1 +/- 5.3 and 12.4 +/- 4.1 mmHg. There was no significant difference between the early or late groups in terms of ICP increases during these predetermined 5 time points.

CONCLUSIONS

In patients with decreased intracranial compliance, a relatively minimally invasive procedure such as PT may lead to significant increases in ICP. The timing of PT does not seem to influence ICP, mortality, pneumonia or early complications. During the PT procedure, ICP should be closely monitored and preventive strategies should be instituted in an attempt to prevent secondary insult to an already severely injured brain.

Relationship of “dose” of intracranial hypertension to outcome in severe traumatic brain injury

Object

It has recently been suggested that the degree of intracranial pressure (ICP) above the treatment goal can be estimated by the area under the curve (AUC) of ICP versus time in patients with severe traumatic brain injury (TBI). The objective of this study was to determine whether the calculated “ICP dose”—the ICP AUC—is related to mortality rate, outcome, and Marshall CT classification.

Methods

Of 135 patients (age range 1–82 years) with severe TBI treated during a 5-year period at the authors' institution, 113 patients underwent ICP monitoring (84%). Ninety-three patients with a monitoring time > 24 hours were included for analysis of ICP AUC calculated using the trapezoidal method. Computed tomography scans were assessed according to the Marshall TBI classification. Patients with Glasgow Outcome Scale scores at 6 months and > 3 years were separated into 2 groups based on outcome.

Results

Sixty patients (65%) had ICP values > 20 mm Hg, and 12 (13%) developed severe intracranial hypertension and died secondary to herniation. A multiple regression analysis adjusting for Glasgow Coma Scale score, age, pupillary abnormalities and Injury Severity Scale score demonstrated that the ICP AUC was a significant predictor of poor outcome at 6 months (p = 0.034) and of death (p = 0.035). However, it did not predict long-term outcome (p = 0.157). The ICP AUC was significantly higher in patients with Marshall head injury Categories 3 and 4 (24 patients) than in those with Category 2 (23 patients, p = 0.025) and Category 5 (46 patients, p = 0.021) TBIs using the worst CT scan obtained.

Conclusions

The authors found a significant relationship between the dose of ICP, the worst Marshall CT score, and patient outcome, suggesting that the AUC method may be useful in refining and improving the treatment of ICP in patients with TBI.

Management of intracranial hypertension

Effective management of intracranial hypertension involves meticulous avoidance of factors that precipitate or aggravate increased intracranial pressure. When intracranial pressure becomes elevated, it is important to rule out new mass lesions that should be surgically evacuated. Medical management of increased intracranial pressure should include sedation, drainage of cerebrospinal fluid, and osmotherapy with either mannitol or hypertonic saline. For intracranial hypertension refractory to initial medical management, barbiturate coma, hypothermia, or decompressive craniectomy should be considered. Steroids are not indicated and may be harmful in the treatment of intracranial hypertension resulting from traumatic brain injury.

Pediatric idiopathic intracranial hypertension

Our understanding of pediatric idiopathic intracranial hypertension has been refined since Dr. Simmons Lessell's review in 1992. The use of rigorous methodologies and standard definitions in recent studies has demonstrated distinct demographic trends. Specifically, the incidence of idiopathic intracranial hypertension seems to be increasing among adolescent children, and among older children its clinical picture is similar to that of adult idiopathic intracranial hypertension (female and obese). Within younger age groups there are more boys and nonobese children who may develop idiopathic intracranial hypertension. The pathogenesis of the disease has yet to be elucidated. Idiopathic intracranial hypertension among young children has been associated with several new etiologies, including recombinant growth hormone and all-trans-retinoic acid. More modern neuroimaging techniques such as MRI and MRI-venograms are being used to exclude intracranial processes. Although most cases of pediatric idiopathic intracranial hypertension improve with medical treatment, those who have had visual progression despite medical treatment have undergone optic nerve sheath fenestration and lumboperitoneal shunting. Because idiopathic intracranial hypertension in young children appears to be a different disorder than in adolescents and adults, separate diagnostic criteria for younger children are warranted. We propose new criteria for pediatric idiopathic intracranial hypertension in which children should have signs or symptoms consistent with elevated intracranial pressure, be prepubertal, have normal sensorium, can have reversible cranial nerve palsies, and have an opening cerebrospinal fluid pressure greater than 180 mm H(2)O if less than age 8 and papilledema is present, but greater than 250 mm H(2)0 if age 8 or above or less than 8 without papilledema.

Refractory intracranial hypertension and "second-tier" therapies in traumatic brain injury

OBJECTIVE

To quantify the occurrence of high intracranial pressure (HICP) refractory to conventional medical therapy after traumatic brain injury (TBI) and to describe the use of more aggressive therapies (profound hyperventilation, barbiturates, decompressive craniectomy).

DESIGN

Prospective study of 407 consecutive TBI patients

SETTING

Three neurosurgical intensive care units (ICU).

MEASUREMENTS AND RESULTS

Intracranial pressure (ICP) was studied during the first week after TBI; 153 patients had at least 1 day of ICP>20 mmHg. Early surgery was necessary for 221 cases, and standard medical therapy [sedation, mannitol, cerebrospinal fluid (CSF) withdrawal, PaCO2 30-35 mmHg] was used in 135 patients. Reinforced treatment (PaCO2 25-29 mmHg, induced arterial hypertension, muscle relaxants) was used in 179 cases (44%), and second-tier therapies in 80 (20%). Surgical decompression and/or barbiturates were used in 28 of 407 cases (7%). Six-month outcome was recorded in 367 cases using the Glasgow outcome scale (GOS). The outcome was favorable (good recovery or moderate disability) in 195 cases (53%) and unfavorable (all the other categories) in 172 (47%). HICP was associated with worse outcome. Outcome for cases who had received second-tier therapies was significantly worse (43% favorable at 6 months, p=0.03).

CONCLUSIONS

HICP is frequent and is associated with worse outcome. ICP was controlled by early surgery and first-tier therapies in the majority of cases. Profound hyperventilation, surgical decompression and barbiturates were used in various combinations in a minority of cases. The indications for surgical decompression and/or barbiturates seem restricted to less than 10% of severe TBI.

Hypertonic saline: a clinical review

Literature suggest that hypertonic saline (HTS) solution with sodium chloride concentration greater than the physiologic 0.9% can be useful in controlling elevated intracranial pressure (ICP) and as a resuscitative agent in multiple settings including traumatic brain injury (TBI). In this review, we discuss HTS mechanisms of action, adverse effects, and current clinical studies. Studies show that HTS administered during the resuscitation of patients with a TBI improves neurological outcome. HTS also has positive effects on elevated ICP from multiple etiologies, and for shock resuscitation. However, a prospective randomized Australian study using an aggressive resuscitation protocol in trauma patients showed no difference in amount of fluids administered during prehospital resuscitation, and no differences in ICP control or neurological outcome. The role of HTS in prehospital resuscitation is yet to be determined. The most important factor in improving outcomes may be prevention of hypotension and preservation of cerebral blood flow. In regards to control of elevated ICP during the inpatient course, HTS appears safe and effective. Although clinicians currently use HTS with some success, significant questions remain as to the dose and manner of HTS infusion. Direct protocol comparisons should be performed to improve and standardize patient care.

Management of intracranial hypertension

Effective treatment of intracranial hypertension involves meticulous avoidance of factors that precipitate or aggravate increased intracranial pressure. When intracranial pressure becomes elevated, it is important to rule out new mass lesions that should be surgically evacuated. medical management of increased intracranial pressure should include sedation and paralysis, drainage of cerebrospinal fluid, and osmotherapy with either mannitol or hypertonic saline. For intracranial hypertension refractory to initial medical management, barbiturate coma, hypothermia, or decompressive craniectomy should be considered. Steroids are not indicated and may be harmful in the treatment of intracranial hypertension resulting from traumatic brain injury.

Hyponatremia in the neurosurgical patient: epidemiology, pathophysiology, diagnosis, and management

OBJECTIVE

Hyponatremia is an important and common electrolyte disorder in critically ill neurosurgical patients that has been reported in association with a number of different primary diagnoses. The correct diagnosis of the pathophysiological cause is vital because it dramatically alters the treatment approach.

METHODS

We review the epidemiology and presentation of patients with hyponatremia, the pathophysiology of the disorder with respect to sodium and fluid balance, and the diagnostic procedures for determining the correct cause.

RESULTS

We then present the various treatment options, including discussion of one of the newest groups of agents, the arginine vasopressin receptor antagonists, currently under study for the treatment of hyponatremia in neurosurgical patients.

CONCLUSION

Hyponatremia is a serious comorbidity in neurosurgical patients that requires particular attention as its treatment varies by cause and its consequences can affect neurological outcome.

Association between outcome, cerebral pressure reactivity and slow ICP waves following head injury

OBJECTIVE

To investigate the relationships between slow vasogenic waves ('B waves') of intracranial pressure (ICP), pressure-reactivity and outcome after traumatic brain injury.

MATERIAL AND METHOD

193 head-injured patients (age 34 +/- 16.7 years; median GCS 6) were monitored from 1997 to 2002. ICP, arterial blood pressure (ABP) were continuously monitored. Pressure-reactivity index (PRx) and magnitude of ICP slow waves were evaluated using the bed-side computers.

RESULTS

Distribution of PRx in different outcome groups indicated that pressure-reactivity was significantly worse in patients with fatal outcome. A magnitude of spontaneous slow waves of ICP was gradually decreasing in poorer outcome grades. Mortality indicated threshold rise from 20% to 70% when averaged PRx increased above 0.3 (p < 0.01). There was no threshold for mortality observed along distribution of magnitude of ICP slow waves. Mortality gradually increased when the magnitude of slow waves decreased (R = -0.26; p < 0.0001).

CONCLUSION

Inadequate pressure-reactivity and low magnitude of slow vasogenic waves of ICP are associated with fatal outcome after head injury. Based on brain monitoring data, differentiation between favourable outcome and severe disability is more problematic than differentiation between survivors and non-survivors.

Traumatic brain injury and stabilisation of long bone fractures: an update

In the era of "damage control orthopaedics", the timing and type of stabilisation of long bone fractures in patients with associated severe traumatic brain injury has been a topic of lively debate. This review summarises the current evidence available regarding the management of these patients. There appear to be no clear treatment guidelines. Irrespective of the treatment protocol followed, if secondary brain damage is to be avoided at all times, ICP monitoring should be used, both in the intensive care unit and in the operating theatre during surgical procedures, since aggressive ICP management appears to be related to improved outcomes. Treatment protocols should be based on the individual clinical assessment, rather than mandatory time policies for fixation of long bone fractures.

In situ detection of intracerebral cytokine expression after human brain contusion

The study was undertaken to analyze intracerebral expression of pro- and anti-inflammatory cytokines after traumatic brain injury (TBI) in man in order to compare the findings with previous experimental data regarding the pathogenesis of secondary brain injury. Contused brain tissue biopsies were obtained from 12 consecutive patients undergoing surgery for brain contusions 3 h to 5 days after trauma. Cytokine expression was analyzed by in situ hybridization and immunohistochemistry. In patients undergoing surgery less than 24 h after trauma, strong expression of both the pro-inflammatory cytokines interleukin (IL)-1-beta, IL-6 and interferon (IFN)-gamma and the anti-inflammatory cytokine IL-4 was detected. In patients undergoing surgery between 3 and 5 days after trauma, IL-4 expression was significantly lower (P < 0.05) compared to the patients operated early. IL-1-beta and IFN-gamma expression remained strong in comparison to IL-6 and IL-4 expression (P < 0.05). Immunohistochemistry for IL-1-beta confirmed that the protein was produced with a temporal and regional pattern that corresponded to in situ hybridization results. The study provides in situ data on intracerebral cytokine expression after contusion in the clinical setting. Strong intracerebral cytokine expression occurs in the perilesional zone both in the early and the delayed phase after traumatic brain injury in humans. The temporal regulation of pro- and anti-inflammatory cytokines differs which reveals different therapeutic windows for pharmacological intervention.

Moderate controlled cortical contusion in pigs: effects on multi-parametric neuromonitoring and clinical relevance

Over the last decade, routine neuromonitoring of ICP and CPP has been extended with new on-line techniques such as microdialysis, tissue oxygen (ptiO(2)), acid-base balance (ptiCO(2), pH) and CBF measurements, which so far have not lead to clear-cut therapy approaches in the neurointensive care unit. This is partially due to the complex pathophysiology following a wide-range of brain injuries, and the lack of suitable animal models allowing simultaneous, clinically relevant neuromonitoring under controlled conditions. Therefore, a controlled cortical impact (CCI) model in large animals (pig) has been developed. After placement of microdialysis, ptiO(2), temperature and ICP catheters, an unilateral CCI injury (2.6-2.8 m/sec velocity, 9 mm depth, 400 ms dwell time) was applied and neuromonitoring continued for 10 h. CCI caused a rapid drop in CPP, ptiO(2) and glucose, whereas ICP, glutamate and lactate increased significantly. Most parameters returned to baseline values within hours. Lactate stayed elevated significantly throughout the experiment, but the lactate-to-pyruvate ratio (LPR) changed only slightly, indicating no severely ischemic CBF. Contralateral parameters were not affected significantly. Evaluation of brain water content and histology (12 h post-CCI) showed ipsilateral brain swelling by 5% and massive cell damage underneath the injury site which correlated with changes of ICP, CPP, glutamate, lactate, and ptiO(2) within the first hours post-CCI. Moderate controlled cortical contusion in pigs induced a complex pattern of pathophysiological processes which led to 'early' histological damage. Thus, this new large animal model will enable us to investigate the effect of therapeutic interventions on multi-parametric neuromonitoring and histological outcome, and to translate the data into clinical practice.

Cerebral edema leading to decompressive craniectomy: an assessment of the preceding clinical and neuromonitoring trends

The aim of this study was to examine the pre-operative clinical and neuromonitoring courses in patients with a decompressive craniectomy to assess and to compare clinical and neuromonitoring signs indicating extensive cerebral edema. We conducted a retrospective analysis of the clinical signs and courses of simultaneous monitoring of intracranial pressure (ICP) and cerebral oxygenation (PtiO2) in 26 consecutive patients who were sedated and treated with a decompressive craniectomy due to extensive cerebral edema after aneurysmal subarachnoid hemorrhage (SAH) (n = 20) or severe head injury (SHI) (n = 6). Pathological monitoring trends always preceded clinical deterioration. In 18 of 26 patients extensive cerebral edema was indicated solely by increasing ICP > 20 mmHg or decreasing PtiO2 < 10 mmHg or both. Anisocoria occurred in only 8 of 26 patients. As opposed to SHI patients, 9 of 20 SAH patients showed decreasing PtiO2 as first warning sign clearly before neurological deterioration or ICP increase. This series shows the utility of combined ICP and PtiO2 monitoring in patients who develop extensive cerebral edema. Pathological monitoring trends indicate deterioration prior to clinical signs which offers a wider therapeutical window. PtiO2 monitoring appears to be particularly valuable after aneurysmal SAH as adjunct to ICP monitoring and CT imaging.

Evolving lesions in traumatic subarachnoid hemorrhage: prospective study of 110 patients with emphasis on the role of ICP monitoring

We have consecutively studied 110 patients with traumatic subarachnoid hemorrhage (tSAH) on the first Computed Tomography (CT) scan (obtained in each case within 3 hours from injury). The only exclusion criteria were brain death on admission, and severe hypotension due to extracranial injuries. All CTs were reviewed by one of us and the "worst" CT examination was determined. We defined the worst CT examination as that showing the most extensive degree of parenchymal-associated damage. Intracranial pressure was monitored in 25 severely head injured patients. Seventy-four patients (66%) showed an evolution from the initial CT scan (worst CT not corresponding to the admission CT). The outcome was favorable in 53 cases (73%) of patients with evolving lesions and in 32 cases (89%) with non evolving lesion. In the 25 severely head injured patients, Intra-cranial Pressure (ICP) monitoring (in combination with scheduled repeat CT scan) was helpful to identify the timing of the worst parenchymal damage and of surgery in those patients with an initial normal intracranial pressure in spite of an evolving lesion.

Absence of a diastolic velocity notch does not indicate hyperemia in traumatic brain injured patients without elevated cerebral blood flow velocity

Elevated blood flow velocity (BFV), measured by transcranial Doppler (TCD), has been associated with hyperemia and cerebral vasospasm. This study examined whether the lack of a diastolic notch within the TCD waveform was associated with relative hyperemia within 5 days after injury in 35 traumatic brain injured (TBI) patients. Hyperemia (avD(O2) of < 4 ml/dL) was present in 16 patients and absent in 19 patients. Two clinicians independently coded TCD waveforms based on the presence of a diastolic notch (88% agreement). There was no significant difference in the presence of a diastolic notch by group; a diastolic notch was present in 57% (11/19) of patients without hyperemia and 81% (13/16) of patients with hyperemia. Sensitivity and specificity of detecting hyperemia using the diastolic notch was 18.7% and 57.9% respectively. The results showed that relative hyperemia was present without an elevation in blood flow velocities, and that the lack of a diastolic notch did not detect the presence of hyperemia in the TBI patient.

Early IL-6 plasma concentrations correlate with severity of brain injury and pneumonia in brain-injured patients

BACKGROUND

Brain injury as well as early inflammatory and endocrine responses were found to be indicators for infectious complications in patients with multiple injuries. In this context, brain-derived inflammatory response as well as centrally triggered neuroendocrine activation and systemic immunodepression seem to be of major importance. Therefore, we hypothesize that a circulating index of inflammatory or endocrine function measured soon after brain injury (in patients with admission Glasgow Coma Scale [GCS] score of 4-7) would discriminate severe from moderate injury as indexed by GCS status on postinjury day 7.

METHODS

In a retrospective study, 25 patients with either acute traumatic brain injury or cerebral hemorrhage and an initial GCS score of 4 to 7 were examined. Blood samples were obtained at different time points, and different immune variables and neuroendocrine hormones were determined. According to the GCS score on day 7, patients were divided into two groups (GCS score > or = 8, moderate brain injury; and GCS score < 8, severe brain injury or patients who died within the first week) for comparison of variables. Concluding from the results of this retrospective analysis, in a prospective study patients (n = 26) were divided into two groups according to their interleukin (IL)-6 plasma concentrations on day 1 (IL-6 > or = 100 pg/mL and IL 6 < 100 pg/mL). After 7 days, the GCS score, the infection rate, and the mortality were compared between these two groups.

RESULTS

In the retrospective study, we could show that severe brain injury (as assessed by GCS score and mortality on day 7) was associated with high plasma levels of pro- and anti-inflammatory cytokines, acute phase proteins, and neuroendocrine hormones within 2 to 6 hours after the acute event. Among the investigated variables, elevated IL-6 plasma concentrations were stable up to 1 day after the acute event with a high predictive value with regard to the short-term prognosis and incidence of infectious complications within the first week. Because of this stability during the first 24 hours, we selected IL-6 for further studies. In the prospective study with a calculated cut-off IL-6 plasma concentration of 100 pg/mL on day 1, the predictive value of this parameter regarding the severity of the brain injury was fully confirmed (positive predictive value, 0.94; this value represents the observed pretest probability of 0.62). All patients who died (n = 5) or developed infectious complications within the first week (n = 8) showed plasma IL-6 levels > or = 100 pg/mL on day 1.

CONCLUSION

The IL-6 plasma level 1 day after the acute event with a cut-off of 100 pg/mL (Immulite) seems to be a predictor for short-term prognosis and infectious complications in brain-injured patients.

Treatment window for hypothermia in brain injury

OBJECT

The goal of this study was to evaluate the therapeutic window for hypothermia treatment following experimental brain injury by measuring edema formation and functional outcome.

METHODS

Traumatic brain injury (TBI) was produced in anesthetized rats by using cortical impact injury. Edema was measured in the ipsilateral and contralateral hemispheres by subtracting dry weight from wet weight, and neurological function was assessed using a battery of behavioral tests 24 hours after TBI. In injured rats, it was found that brain water levels were elevated at I hour postinjury, compared with those in sham-injured control animals, and that edema peaked at 24 hours and remained elevated for 4 days. Hypothermia (3 hours at 30 degrees C) induced either immediately after TBI or 60 minutes after TBI significantly reduced early neurological deficits. Delay of treatment by 90 or 120 minutes postinjury did not result in this neurological protection. Immediate administration of hypothermia also significantly decreased the peak magnitude of edema at 24 hours and 48 hours postinjury, compared with that in normothermic injured control animals. When delayed by 90 minutes, hypothermia did not affect the pattern of edema formation.

CONCLUSIONS

When hypothermia was administered immediately or 60 minutes after TBI, injured rats showed an improvement in functional outcome and a decrease in edema. Delayed hypothermia treatment had no effect on functional outcome or on edema.

Multiple intracranial lesions in head injury: clinical considerations, prognostic factors, management, and results in 95 patients

BACKGROUND

The goal of this study was to identify clinical and radiological predictors of prognosis in patients with multiple post-traumatic intracranial lesions.

METHODS

We reviewed 95 patients (75 male and 20 female) between the ages of 18 and 70 (average 38) admitted between 1993 and 2000 with multiple post-traumatic intracranial lesions. Intracranial pressure (ICP) monitoring was carried out in 67 patients (70%); 77 received intensive care unit (ICU) treatment. Since in all cases it was possible to identify a clearly predominant lesion, 3 groups of patients emerged from the data: the first with extradural hematoma (EDH), the second with a combination of homolateral subdural (SDH) and intracerebral hematoma (ICH), and the third with pure focal intracerebral hematoma (ICH).

RESULTS

Twenty-seven patients were treated conservatively, 2 of whom died (7.4%); both had bilateral ICH and compression of the basal cisterns. Sixty-eight patients underwent one or more surgeries; 8 died (11.7%). In the group with EDH-predominant lesions (27 cases) all patients were operated (16 for multiple lesions); no one died. In the group with SDH+ICH-predominant lesions, 26 of 32 patients were operated (10 had multiple procedures); 6 died (18.7%), 3 were vegetative. In the group with ICH-predominant lesion, 15 of 36 patients were operated (7 bilaterally); 4 died (11%). Decompressive craniectomy proved to be a useful means to control ICP. Bilateral lobectomy is not recommended because of poor results. Immediate postoperative computed tomography (CT) scan proved to be mandatory to detect additional surgically treatable lesions (16 cases). Statistical analysis was performed by means of chi(2) analysis and multiple linear regression model. The multiple linear regression model was used to ascertain risk factors independently associated with the outcome. The type of lesion (presence of SDH+ICH predominant lesion), the worst recorded Glasgow Coma Scale (GCS) score, the presence of prolonged increased ICP, and the absence of pupillary reflexes were all statistically significant predictors of a bad outcome (dead or vegetative state).

CONCLUSIONS

Multiple lesions have the same prognosis as the corresponding single lesions; therefore, their management should be guided by the predominant pathology.

Secondary insults in severe head injury--do multiply injured patients do worse?

OBJECTIVES

To study the occurrence of secondary insults and the influence of extracranial injuries on cerebral oxygenation and outcome in patients with closed severe head injury (Glasgow Coma Scale score < or =8).

DESIGN

Two-year prospective, clinical study.

SETTING

Two intensive care units in a level III trauma center.

PATIENTS

We studied 119 patients. Eighty patients had severe head injury and were divided into two categories: "isolated" severe head injury patients (n = 36, Injury Severity Score <30), and severe head injury patients with associated extracranial injuries (n = 44, Injury Severity Score >29). Thirty-nine patients with extracranial injuries and no head injury served as the control group.

INTERVENTIONS

After patients were admitted to the intensive care unit, we began continuous multimodal cerebral monitoring of intracranial pressure, mean arterial blood pressure, cerebral perfusion pressure, end-tidal Co2, brain tissue Po2 (Licox), jugular bulb oxyhemoglobin saturation in severe head injury patients, and mean arterial blood pressure in the control group. Targets of management included intracranial pressure <20 mm Hg, cerebral perfusion pressure >60 mm Hg, Paco2 > 30 mm Hg, control of cerebral oxygenation, and delayed surgery for non-life-threatening extracranial lesions.

MEASUREMENTS AND MAIN RESULTS

Data were analyzed for critical thresholds. The occurrence of secondary insults (intracranial pressure >20 mm Hg, mean arterial blood pressure <70 mm Hg, cerebral perfusion pressure <60 mm Hg, end-tidal Co2 <30 torr, brain tissue Po2 <10 torr, jugular bulb oxyhemoglobin saturation <50%) was comparable in patients with isolated severe head injury and those with severe head injury with associated extracranial lesions (Abbreviated Injury Scale score < or =5). The duration of intracranial hypertension and arterial hypotension significantly correlated with an unfavorable outcome, independent of the Injury Severity Score. In patients with severe head injury, 1-yr outcome was 29% dead or vegetative, 17% severely disabled, and 54% moderate or good outcome. This was similar to patients with severe head injury and extracranial injuries (31% dead or vegetative, 14% severely disabled, and 56% moderate or good outcome) and was independent of the Injury Severity Score. Patients with no head injury had less secondary insults (mean arterial blood pressure <70 mm Hg, p <.01) and a better outcome compared with both severe head injury groups (p <.044).

CONCLUSIONS

In patients with severe head injury who have targeted management including intracranial pressure- and cerebral perfusion pressure-guided therapy and delayed surgery for extracranial lesions, the occurrence of secondary insults in the intensive care unit and long-term neurological outcome were comparable and independent of the presence of extracranial lesions (Abbreviated Injury Severity level < or =5). A severe head injury is still a major contributor predicting an unfavorable outcome in multiply injured patients.