High-dose barbiturate control of elevated intracranial pressure in patients with severe head injury

Visualization of the Intracranial Pressure and Time Burden in Childhood Brain Trauma: What We Have Learned One Decade on With KidsBrainIT

To validate the intracranial pressure (ICP) dose-response visualization plot for the first time in a novel prospectively collected pediatric traumatic brain injury (pTBI) data set from the multi-center, multi-national KidsBrainIT consortium. Prospectively collected minute-by-minute ICP and mean arterial blood pressure time series of 104 pTBI patients were categorized in ICP intensity-duration episodes. These episodes were correlated with the 6-month Glasgow Outcome Score (GOS) and displayed in a color-coded ICP dose-response plot. The influence of cerebrovascular reactivity and cerebral perfusion pressure (CPP) were investigated. The generated ICP dose-response plot on the novel data set was similar to the previously published pediatric plot. This study confirmed that higher ICP episodes were tolerated for a shorter duration of time, with an approximately exponential decay curve delineating the positive and negative association zones. ICP above 20 mm Hg for any duration in time was associated with poor outcome in our patients. Cerebrovascular reactivity state did not influence their respective transition curves above 10 mm Hg ICP. CPP below 50 mm Hg was not tolerated, regardless of ICP and duration, and was associated with worse outcome. The ICP dose-response plot was reproduced in a novel and independent pTBI data set. ICP above 20 mm Hg and CPP below 50 mm Hg for any duration in time were associated with worse outcome. This highlighted a pressing need to reduce pediatric ICP therapeutic thresholds used at the bedside.

Hostility prevents the tragedy of the commons in metapopulation with asymmetric migration: A lesson from queenless ants

A colony of the queenless ant species, Pristomyrmex punctatus, can broadly be seen as consisting of small-body sized worker ants and relatively larger body-sized cheater ants. Hence, in the presence of intercolony migration, a set of constituent colonies act as a metapopulation exclusively composed of cooperators and defectors. Such a setup facilitates an evolutionary game-theoretic replication-selection model of population dynamics of the ants in a metapopulation. Using the model, we analytically probe the effects of territoriality induced hostility. Such hostility in the ant metapopulation proves to be crucial in preventing the tragedy of the commons, specifically, the workforce, a social good formed by cooperation. This mechanism applies to any metapopulation-not necessarily the ants-composed of cooperators and defectors where interpopulation migration occurs asymmetrically, i.e., cooperators and defectors migrate at different rates. Furthermore, our model validates that there is evolutionary benefit behind the queenless ants' behavior of showing more hostility towards the immigrants from nearby colonies than those from the far-off ones. In order to calibrate our model's parameters, we have extensively used the data available on the queenless ant species, P. punctatus.

Intracranial Pressure Monitoring and Treatment Thresholds in Acute Neural Injury: A Narrative Review of the Historical Achievements, Current State, and Future Perspectives

Since its introduction in the 1960s, intracranial pressure (ICP) monitoring has become an indispensable tool in neurocritical care practice and a key component of the management of moderate/severe traumatic brain injury (TBI). The primary utility of ICP monitoring is to guide therapeutic interventions aimed at maintaining physiological ICP and preventing intracranial hypertension. The rationale for such ICP maintenance is to prevent secondary brain injury arising from brain herniation and inadequate cerebral blood flow. There exists a large body of evidence indicating that elevated ICP is associated with mortality and that aggressive ICP control protocols improve outcomes in severe TBI patients. Therefore, current management guidelines recommend a cerebral perfusion pressure (CPP) target range of 60-70 mm Hg and an ICP threshold of >20 or >22 mm Hg, beyond which therapeutic intervention should be initiated. Though our ability to achieve these thresholds has drastically improved over the past decades, there has been little to no change in the mortality and morbidity associated with moderate-severe TBI. This is a result of the "one treatment fits all" dogma of current guideline-based care that fails to take individual phenotype into account. The way forward in moderate-severe TBI care is through the development of continuously derived individualized ICP thresholds. This narrative review covers the topic of ICP monitoring in TBI care, including historical context/achievements, current monitoring technologies and indications, treatment methods, associations with patient outcome and multi-modal cerebral physiology, present controversies surrounding treatment thresholds, and future perspectives on personalized approaches to ICP-directed therapy.

Current status and outlook for the management of intracranial hypertension after traumatic brain injury: decompressive craniectomy, therapeutic hypothermia, and barbiturates

INTRODUCTION

Increased intracranial pressure (ICP) has been associated with poor neurological outcomes and increased mortality in patients with severe traumatic brain injury (TBI). Traditionally, ICP-lowering therapies are administered using an escalating approach, with more aggressive options reserved for patients showing no response to first-tier interventions, or with refractory intracranial hypertension.

DEVELOPMENT

The therapeutic value and the appropriate timing for the use of rescue treatments for intracranial hypertension have been a subject of constant debate in literature. In this review, we discuss the main management options for refractory intracranial hypertension after severe TBI in adults. We intend to conduct an in-depth revision of the most representative randomised controlled trials on the different rescue treatments, including decompressive craniectomy, therapeutic hypothermia, and barbiturates. We also discuss future perspectives for these management options.

CONCLUSIONS

The available evidence appears to show that mortality can be reduced when rescue interventions are used as last-tier therapy; however, this benefit comes at the cost of severe disability. The decision of whether to perform these interventions should always be patient-centred and made on an individual basis. The development and integration of different physiological variables through multimodality monitoring is of the utmost importance to provide more robust prognostic information to patients facing these challenging decisions.

Risk factors and a novel cerebral infarction extent scoring system for postoperative cerebral ischemia in patients with ischemic Moyamoya disease

Postoperative cerebral ischemic complication is the most common complication of revascularization surgery for patients with moyamoya disease (MMD). This retrospective study was conducted on 63 patients with ischemic MMD. Postoperative ischemia occurred in 15 of the 70 revascularization operations performed for patients after surgical revascularization, translating to an incidence of 21.4%. Univariate analysis revealed that onset infarction (p = 0.015), posterior cerebral artery involvement (p = 0.039), strict perioperative management (p = 0.001), interval time between transient ischemic attack (TIA) or infarction presentation and operation (p = 0.002) and preoperatively cerebral infarction extent score (CIES) (p = 0.002) were significantly associated with postoperative cerebral ischemia. Multivariate analysis revealed that strict perioperative management (OR = 0.163; p = 0.047), and preoperatively CIES (OR = 1.505; p = 0.006) were independently associated with postoperative cerebral ischemia-related complications. After comprehensive improvement of perioperative management protocol, the incidence of symptomatic infarction declined to 7.4% (4 out of 54). Analysis of the area under the receiver operating characteristic curve (AUROC) indicated CIES was a predictor for both postoperative ischemia and high follow-up modified Rankin Scale scores. In summary, strict perioperative management and CIES were identified as independent risk factors for postoperative ischemic complications in ischemic MMD, demonstrating that comprehensive and individualized perioperative management improve postoperative outcomes in patients with MMD. Furthermore, application of CIES to evaluate pre-existing cerebral infarction can improve the management of patients.

Dominant Fronto-temporal Lobectomy for Refractory Intracranial Hypertension following an Acute Arterial Ischemic Stroke in a Child

Fronto-temporal lobectomy for refractory intracranial hypertension following an acute arterial ischemic stroke in a child is rarely performed following failed conventional measures including decompressive craniectomy. We present a case of a 10-year-old child who presented with acute ischemic stroke with intractable cerebral edema and failed conventional measures including decompressive craniectomy and had significant neurological recovery following frontotemporal lobectomy.

Review: Emerging Eye-Based Diagnostic Technologies for Traumatic Brain Injury

The study of ocular manifestations of neurodegenerative disorders, Oculomics, is a growing field of investigation for early diagnostics, enabling structural and chemical biomarkers to be monitored overtime to predict prognosis. Traumatic brain injury (TBI) triggers a cascade of events harmful to the brain, which can lead to neurodegeneration. TBI, termed the "silent epidemic" is becoming a leading cause of death and disability worldwide. There is currently no effective diagnostic tool for TBI, and yet, early-intervention is known to considerably shorten hospital stays, improve outcomes, fasten neurological recovery and lower mortality rates, highlighting the unmet need for techniques capable of rapid and accurate point-of-care diagnostics, implemented in the earliest stages. This review focuses on the latest advances in the main neuropathophysiological responses and the achievements and shortfalls of TBI diagnostic methods. Validated and emerging TBI-indicative biomarkers are outlined and linked to ocular neuro-disorders. Methods detecting structural and chemical ocular responses to TBI are categorised along with prospective chemical and physical sensing techniques. Particular attention is drawn to the potential of Raman spectroscopy as a non-invasive sensing of neurological molecular signatures in the ocular projections of the brain, laying the platform for the first tangible path towards alternative point-of-care diagnostic technologies for TBI.

Invention of a non-invasive intracranial pressure (ICP) monitoring system - an enlightenment from a hydrocephalus study

BACKGROUND

Mechanical obstruction is the most common cause of shunt failure for hydrocephalic patients. However, the diagnosis is extremely challenging and often requires invasive testing methods. Thus, a simple and non-invasive technique is in urgent need to predict the intracranial pressure (ICP) of hydrocephalic patients during their post-surgical follow-up, which could help neurosurgeons to determine the conditions of the shunt system.

MATERIALS AND METHODS

Two groups of patients were enrolled in the current study. In group I, patients were enrolled as they were diagnosed with high ICP hydrocephalus and received shunt surgery. The shunt valve pressures were taken for their post-surgical ICP. Meanwhile, the participants of group II exhibited abnormally increased lumbar puncture opening pressure (LPOP; from 180 to 400 mmH₂O). Both the ICP and LPOP were used to match with their corresponding tympanic membrane temperature (TMT).

RESULTS

When patients' ICP were in the normal range (group I, from 50 to 180 mmH₂O), the TMT correlated with ICP in a linear regression model (R² = 0.59, p < 0.001). Interestingly, when patients exhibited above-normal ICP (LPOP was from 180 to 400 mmH₂O), their TMT fit well with the ICP in a third-order polynomial regression (R² = 0.88). When the ICP was 287.98 mmH₂O, the TMT approached the vertex, which was 38.54 °C. Based on this TMT-ICP algorithm, we invented a non-invasive ICP monitor system. Interestingly, a tight linear correlation was detected between the ICP data drawn from the non-invasive device and Codman ICP monitoring system (R² = 0.93, p < 0.01).

CONCLUSIONS

We believe the TMT-ICP algorithm (the Y-Jiang model) could be used for preliminary prediction of shunt malfunction as well as monitoring ICP changes.

Management of Severe Traumatic Brain Injury in Pediatric Patients

The optimal management of severe traumatic brain injury (TBI) in the pediatric population has not been well studied. There are a limited number of research articles studying the management of TBI in children. Given the prevalence of severe TBI in the pediatric population, it is crucial to develop a reference TBI management plan for this vulnerable population. In this review, we seek to delineate the differences between severe TBI management in adults and children. Additionally, we also discuss the known molecular pathogenesis of TBI. A better understanding of the pathophysiology of TBI will inform clinical management and development of therapeutics. Finally, we propose a clinical algorithm for the management and treatment of severe TBI in children using published data.

Early use of barbiturates is associated with increased mortality in traumatic brain injury patients from a propensity score-based analysis of a prospective cohort

Barbiturates are proposed as a second/third line treatment for intracranial hypertension in traumatic brain injury (TBI) patients, but the literature remains uncertain regarding their benefit/risk balance. We aimed to evaluate the impact of barbiturates therapy in TBI patients with early intracranial hypertension on the intensive care unit (ICU) survival, the occurrence of ventilator-associated pneumonia (VAP), and the patient’s functional status at three months. We used the French AtlanREA prospective cohort of trauma patients. Using a propensity score-based methodology (inverse probability of treatment weighting), we compared patients having received barbiturates within the first 24 hours of admission (barbiturates group) and those who did not (control group). We used cause-specific Cox models for ICU survival and risk of VAP, and logistic regression for the 3-month Glasgow Outcome Scale (GOS) evaluation. Among the 1396 patients with severe trauma, 383 had intracranial hypertension on admission and were analyzed. Among them, 96 (25.1%) received barbiturates. The early use of barbiturates was significantly associated with increased ICU mortality (HR = 1.85, 95%CI 1.03–3.33). However, barbiturates treatment was not significantly associated with VAP (HR = 1.02, 95%CI 0.75–1.41) or 3-month GOS (OR = 1.67, 95%CI 0.84–3.33). Regarding the absence of relevant clinical trials, our results suggest that each early prescription of barbiturates requires a careful assessment of the benefit/risk ratio.

Anesthesia-Associated Periodic Discharges

PURPOSE

Anesthetic agents have been widely used in the treatment of refractory status epilepticus and the medical management of increased intracranial pressure whenever the goal is therapeutic burst suppression. Periodic patterns typically consisting of generalized periodic discharges (GPDs) following emergence from anesthesia have been described in several case reports. However, their clinical significance and in particular whether these patterns are epileptiform remains unclear.

METHODS

This is a single-center, retrospective, observational study examining EEG patterns following emergence from pharmacologically induced burst suppression. Clinical and EEG data were collected. Patients who developed GPDs following anesthetic wean were compared with those who did not.

RESULTS

Over 4.5 years, 14 patients developed GPDs related to anesthetic withdrawal. The GPDs had a frequency between 0.5 and 2.5 Hz. Generalized periodic discharges related to anesthetic withdrawal were transient, with a median duration of 40 hours (interquartile range, 24-48 hours). Notably, in all patients, the pattern was stimulus dependent. When compared with a control group of 19 consecutive patients who did not develop a generalized periodic pattern in the context of the anesthetic wean, there was no significant difference in the status epilepticus relapse between the two groups (29% vs. 44%; P = 0.63). Patients in the GPD group were more likely to be on pentobarbital (93% vs. 58%; P = 0.05) and were more likely to have concomitant systemic infection treated with antibiotics compared with the control group (86% vs. 42%; P = 0.02).

CONCLUSIONS

Generalized periodic patterns are common following the wean of intravenous anesthetics (particularly pentobarbital) and likely represent a transitional encephalopathic state in a subset of patients. Their morphology is distinct and can be differentiated from the reemergence of status epilepticus (if the latter was the indication for anesthetic treatment). Failure to recognize this pattern may lead to prolonged unnecessary treatments if it is mistaken for the emergence of seizure activity. The presence of concomitant systemic infection and associated antibiotic treatment may be risk factors for the development of this pattern.

The role of tranexamic acid in traumatic brain injury

Evidence from recent trials evaluating efficacy of antifibrinolytic agents in the context of traumatic brain injury may lead to changes in the management of patients with traumatic brain injury. Tranexamic acid (TXA) reduces the proteolytic action of plasmin on fibrin clots, resulting in an inhibition of fibrinolysis and stabilisation of established blood clots. There has been significant interest in use of the drug as a therapeutic agent in the context of severe haemorrhage; however, considerable controversies regarding its efficacy remain. A number of trials have demonstrated a small but significant decrease in mortality following its administration, but the results have been somewhat inconsistent and may not be generalisable. The results of the CRASH-3 trial were that there was no statistical difference in the number of traumatic brain injury related deaths (18.5% with TXA and 19.8% with placebo; relative risk [RR] 0·94; 95% confidence interval [CI] 0·86-1·02). Nonetheless, there was a subgroup of patients for whom TXA appeared to provide benefit, and this was in patients with mild and moderate injury (with a Glasgow Coma Score > 8). This is potentially a very important finding that may have huge potential implications; however, we believe it does not currently provide indisputable evidence to support the administration of TXA to all patients with TBI. Further work is required to better define the subset of patients who may benefit as well as to evaluate the long-term functional benefit in order to determine which types of severe traumatic brain injury patients would derive more benefits than harms from TXA.

Pentobarbital Coma Use in a Pregnant Patient With Refractory Intracranial Hypertension: A Case Report

OBJECTIVE

Intracranial hypertension is a life-threatening condition that requires emergent diagnosis and management. Although pentobarbital coma for refractory intracranial hypertension has been studied in the general population, this study is the first reported case of pentobarbital coma use in a pregnant patient.

METHODS

We performed a retrospective chart review of a pregnant patient with refractory intracranial hypertension and reviewed the current literature on the role of pentobarbital coma.

RESULTS

We present the case of a 35-year-old woman at 26 weeks of gestation who developed refractory intracranial hypertension secondary to rupture of a dural arteriovenous fistula. The patient was taken to surgery for decompressive hemicraniectomy, clot evacuation, and dural arteriovenous fistula resection. Subsequently, the patient was treated with pentobarbital coma for 5 days and achieved adequate control of her intracranial pressures. The patient and fetus were closely monitored by the obstetrics team with no apparent harm to fetal well-being during her hospital stay. The patient underwent planned cesarean delivery at term, and both the mother and newborn were discharged in stable condition with no known pentobarbital-related complications.

CONCLUSIONS

Thus, we present the first case report demonstrating that pentobarbital coma may be a safe and efficacious option for treating pregnant patients with life-threatening refractory intracranial hypertension. We also provide dosing information for pentobarbital administration. Additional studies and reports involving pregnant patients are needed to better understand the impact of pentobarbital on both the mother and fetus. Furthermore, long-term follow-up of both the mother and newborn is critical to identifying any delayed sequelae of neonatal exposure to pentobarbital.

Sedation-Induced Burst Suppression Predicts Positive Outcome Following Traumatic Brain Injury

While electroencephalogram (EEG) burst-suppression is often induced therapeutically using sedatives in the intensive care unit (ICU), there is hitherto no evidence with respect to its association to outcome in moderate-to-severe neurological patients. We examined the relationship between sedation-induced burst-suppression (SIBS) and outcome at hospital discharge and at 6-month follow up in patients surviving moderate-to-severe traumatic brain injury (TBI). For each of 32 patients recovering from coma after moderate-to-severe TBI, we measured the EEG burst suppression ratio (BSR) during periods of low responsiveness as assessed with the Glasgow Coma Scale (GCS). The maximum BSR was then used to predict the Glasgow Outcome Scale extended (GOSe) at discharge and at 6 months post-injury. A multi-model inference approach was used to assess the combination of predictors that best fit the outcome data. We found that BSR was positively associated with outcomes at 6 months (P = 0.022) but did not predict outcomes at discharge. A mediation analysis found no evidence that BSR mediates the effects of barbiturates or propofol on outcomes. Our results provide initial observational evidence that burst suppression may be neuroprotective in acute patients with TBI etiologies. SIBS may thus be useful in the ICU as a prognostic biomarker.

Moderate and Severe Traumatic Brain Injury

PURPOSE OF REVIEW

Traumatic brain injury (TBI) encompasses a group of heterogeneous manifestations of a disease process with high neurologic morbidity and, for severe TBI, high probability of mortality and poor neurologic outcomes. This article reviews TBI in neurocritical care, hence focusing on moderate and severe TBI, and includes an up-to-date review of the many variables to be considered in clinical care.

RECENT FINDINGS

With advances in medicine and biotechnology, understanding of the impact of TBI has substantially elucidated the distinction between primary and secondary brain injury. Consequently, care of TBI is evolving, with intervention-based modalities targeting multiple physiologic variables. Multimodality monitoring to assess intracranial pressure, cerebral oxygenation, cerebral metabolism, cerebral blood flow, and autoregulation is at the forefront of such advances.

SUMMARY

Understanding the anatomic and physiologic principles of acute brain injury is necessary in managing moderate to severe TBI. Management is based on the prevention of secondary brain injury from resultant trauma. Care of patients with TBI should occur in a dedicated critical care unit with subspecialty expertise. With the advent of multimodality monitoring and targeted biomarkers in TBI, patient outcomes have a higher probability of improving in the future.

Tier-three therapies for refractory intracranial hypertension in adult head trauma

Refractory intracranial hypertension after traumatic brain injury (TBI) is defined as recurrent increase of intracranial pressure (ICP) above 20-22 mmHg for sustained period of time (10-15 min), despite conventional therapies, such as osmotic therapy, cerebral spinal fluid drainage and mild hyperventilation. As such, more aggressive treatments should be taken into consideration. In particular, therapeutic hypothermia, barbiturates administration and decompressive craniectomy are considered as tier-three or "salvage" interventions, as they have shown to be able to control refractory hypertension, but are also associated with an increased risk of significant side effects. The aim of this review is therefore to describe the evidence supporting the use of these tier-three therapies in the management of refractory intracranial hypertension in TBI patients.

Temporal effects of barbiturate coma on intracranial pressure and compensatory reserve in children with traumatic brain injury

Background

The aim was to study the effects of barbiturate coma treatment (BCT) on intracranial pressure (ICP) and intracranial compensatory reserve (RAP index) in children (< 17 years of age) with traumatic brain injury (TBI) and refractory intracranial hypertension (RICH).

Methods

High-resolution monitoring data were used to study the effects of BCT on ICP, mean arterial pressure (MAP), cerebral perfusion pressure (CPP), and RAP index. Four half hour long periods were studied: before bolus injection and at 5, 10, and 24 hours thereafter, respectively, and a fifth tapering period with S-thiopental between < 100 and < 30 μmol/L. S-thiopental concentrations and administered doses were registered.

Results

Seventeen children treated with BCT 2007–2017 with high-resolution data were included; median age 15 (range 6–17) and median Glasgow coma score 7 (range 3–8). Median time from trauma to start of BCT was 44.5 h (range 2.5–197.5) and from start to stop 99.0 h (range 21.0–329.0). Median ICP was 22 (IQR 20–25) in the half hour period before onset of BCT and 16 (IQR 11–20) in the half hour period 5 h later (p = 0.011). The corresponding figures for CPP were 65 (IQR 62–71) and 63 (57–71) (p > 0.05). The RAP index was in the half hour period before onset of BCT 0.6 (IQR 0.1–0.7), in the half hour period 5 h later 0.3 (IQR 0.1–0.7) (p = 0.331), and in the whole BCT period 0.3 (IQR 0.2–0.4) (p = 0.004). Eighty-two percent (14/17) had favorable outcome (good recovery = 8 patients and moderate disability = 6 patients).

Conclusion

BCT significantly reduced ICP and RAP index with preserved CPP. BCT should be considered in case of RICH.

Escalate and De-Escalate Therapies for Intracranial Pressure Control in Traumatic Brain Injury

Severe traumatic brain injury (TBI) is frequently associated with an elevation of intracranial pressure (ICP), followed by cerebral perfusion pressure (CPP) reduction. Invasive monitoring of ICP is recommended to guide a step-by-step “staircase approach” which aims to normalize ICP values and reduce the risks of secondary damage. However, if such monitoring is not available clinical examination and radiological criteria should be used. A major concern is how to taper the therapies employed for ICP control. The aim of this manuscript is to review the criteria for escalating and withdrawing therapies in TBI patients. Each step of the staircase approach carries a risk of adverse effects related to the duration of treatment. Tapering of barbiturates should start once ICP control has been achieved for at least 24 h, although a period of 2–12 days is often required. Administration of hyperosmolar fluids should be avoided if ICP is normal. Sedation should be reduced after at least 24 h of controlled ICP to allow neurological examination. Removal of invasive ICP monitoring is suggested after 72 h of normal ICP. For patients who have undergone surgical decompression, cranioplasty represents the final step, and an earlier cranioplasty (15–90 days after decompression) seems to reduce the rate of infection, seizures, and hydrocephalus.

Current status and outlook for the management of intracranial hypertension after traumatic brain injury: decompressive craniectomy, therapeutic hypothermia, and barbiturates

INTRODUCTION

Increased intracranial pressure has been associated with poor neurological outcomes and increased mortality in patients with severe traumatic brain injury. Traditionally, intracranial pressure-lowering therapies are administered using an escalating approach, with more aggressive options reserved for patients showing no response to first-tier interventions, or with refractory intracranial hypertension.

DEVELOPMENT

The therapeutic value and the appropriate timing for the use of rescue treatments for intracranial hypertension have been a subject of constant debate in literature. In this review, we discuss the main management options for refractory intracranial hypertension after severe traumatic brain injury in adults. We intend to conduct an in-depth revision of the most representative randomised controlled trials on the different rescue treatments, including decompressive craniectomy, therapeutic hypothermia, and barbiturates. We also discuss future perspectives for these management options.

CONCLUSIONS

The available evidence appears to show that mortality can be reduced when rescue interventions are used as last-tier therapy; however, this benefit comes at the cost of severe disability. The decision of whether to perform these interventions should always be patient-centred and made on an individual basis. The development and integration of different physiological variables through multimodality monitoring is of the utmost importance to provide more robust prognostic information to patients facing these challenging decisions.

Pentobarbital Coma With Therapeutic Hypothermia for Treatment of Refractory Intracranial Hypertension in Traumatic Brain Injury Patients: A Single Institution Experience

Introduction Traumatic brain injury (TBI) results in primary and secondary brain injuries. Secondary brain injury can lead to cerebral edema resulting in increased intracranial pressure (ICP) secondary to the rigid encasement of the skull. Increased ICP leads to decreased cerebral perfusion pressure which leads to cerebral ischemia. Refractory intracranial hypertension (RICH) occurs when ICP remains elevated despite first-tier therapies such as head elevation, straightening of the neck, analgesia, sedation, paralytics, cerebrospinal fluid (CSF) drainage, mannitol and/or hypertonic saline administration. If unresponsive to these measures, second-tier therapies such as hypothermia, barbiturate infusion, and/or surgery are employed. Methods This was a retrospective review of patients admitted at Arrowhead Regional Medical Center from 2008 to 2019 for severe TBI who developed RICH requiring placement into a pentobarbital-induced coma with therapeutic hypothermia. Primary endpoints included mortality, good recovery which was designated at Glasgow outcome scale (GOS) of 4 or 5, and improvement in ICP (goal is <20 mmHg). Secondary endpoints included complications, length of intensive care unit (ICU) stay, length of hospital stay, length of pentobarbital coma, length of hypothermia, need for vasopressors, and decompressive surgery versus no decompressive surgery. Results Our study included 18 patients placed in pentobarbital coma with hypothermia for RICH. The overall mortality rate in our study was 50%; with 60% mortality in pentobarbital/hypothermia only group, and 46% mortality in surgery plus pentobarbital/hypothermia group. Maximum ICP prior to pentobarbital/hypothermia was significantly lower in patients who had a prior decompressive craniectomy than in patients who were placed into pentobarbital/hypothermia protocol first (28.3 vs 35.4, p<0.0238). ICP was significantly reduced at 4 hours, 8 hours, 12 hours, 24 hours, and 48 hours after pentobarbital and hypothermia treatment. Initial ICP and maximum ICP prior to pentobarbital/hypothermia was significantly correlated with mortality (p=0.022 and p=0.026). Patients with an ICP>25 mmHg prior to pentobarbital/hypothermia initiation had an increased risk of mortality (p=0.0455). There was no statistically significant difference in mean ICP after 24 hours after pentobarbital/hypothermia protocol in survivors vs non-survivors. Increased time to reach 33°C was associated with increased mortality (r=0.47, p=0.047); with a 10.5-fold increase in mortality for >7 hours (OR 10.5, p=0.039). Conclusion Prolonged cooling time >7 hours was associated with a 10.5-fold increase in mortality and ICP>25 mmHg prior to initiation of pentobarbital and hypothermia is suggestive of a poor response to treatment. We recommend patients with severe TBI who develop RICH should first undergo a 12 x 15 cm decompressive hemicraniectomy because they have better survival and are more likely to have ICP <25 mmHg as the highest elevation of ICP if the ICP were to become and stay elevated again. Pentobarbital and hypothermia should be initiated if the ICP becomes elevated and sustained above 20 mmHg with a prior decompressive hemicraniectomy and refractory to other medical therapies. However, our data suggests that patients are unlikely to survive if there ICP does not decrease to less than 15mmHg at 8 and 12 hours after pentobarbital/hypothermia and remain less than 20 mmHg within first 48 hours.

Management and Challenges of Severe Traumatic Brain Injury

Traumatic brain injury (TBI) is the leading cause of death and disability in trauma patients, and can be classified into mild, moderate, and severe by the Glasgow coma scale (GCS). Prehospital, initial emergency department, and subsequent intensive care unit (ICU) management of severe TBI should focus on avoiding secondary brain injury from hypotension and hypoxia, with appropriate reversal of anticoagulation and surgical evacuation of mass lesions as indicated. Utilizing principles based on the Monro-Kellie doctrine and cerebral perfusion pressure (CPP), a surrogate for cerebral blood flow (CBF) should be maintained by optimizing mean arterial pressure (MAP), through fluids and vasopressors, and/or decreasing intracranial pressure (ICP), through bedside maneuvers, sedation, hyperosmolar therapy, cerebrospinal fluid (CSF) drainage, and, in refractory cases, barbiturate coma or decompressive craniectomy (DC). While controversial, direct ICP monitoring, in conjunction with clinical examination and imaging as indicated, should help guide severe TBI therapy, although new modalities, such as brain tissue oxygen (PbtO₂) monitoring, show great promise in providing strategies to optimize CBF. Optimization of the acute care of severe TBI should include recognition and treatment of paroxysmal sympathetic hyperactivity (PSH), early seizure prophylaxis, venous thromboembolism (VTE) prophylaxis, and nutrition optimization. Despite this, severe TBI remains a devastating injury and palliative care principles should be applied early. To better affect the challenging long-term outcomes of severe TBI, more and continued high quality research is required.

Pentobarbital Induced Hypokalemia: A Worrying Sequela

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High dose barbiturate use has been linked to life threatening hypokalemia and rebound hyperkalemia.

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Pentobarbital is a barbiturates that is used in high doses to induce a coma state to lower intracranial pressures.

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Through constant monitoring of potassium levels and permissive hypokalemia, avoidance of rebound hyperkalemia is achievable.

Introduction

Intracranial hypertension that is not responsive to other therapies can be managed through the use of a barbiturate induced coma. Although potentially effective, there are known complications associated with this treatment, and as such it is typically reserved for the most severe cases. One such sequela of barbiturate induced coma therapy is refractory hypokalemia and subsequent rebound hyperkalemia.

Presentation of case

This case report discusses a patient who experienced hypokalemia during pentobarbital induced coma for unmanageable elevations in intracranial pressure and was treated conservatively to avoid rebound hyperkalemia depicting successful deployment of permissive hypokalemia.

Discussion

It is vital that clinicians understand the possible adverse effects associated with barbiturate induced coma therapy, and that a careful balance be struck between hypokalemia and potassium supplementation to avoid rebound hyperkalemia.

Conclusion

Given that the risk of rebound hyperkalemia is of significant concern in patients who experience hypokalemia on barbiturate induced coma therapy, permissive hypokalemia can be a viable treatment option achieved by lowering the potassium replacement target threshold in such patients.

Intracranial pressure-based barbiturate coma treatment in children with refractory intracranial hypertension due to traumatic brain injury

OBJECTIVE

Refractory intracranial pressure (ICP) hypertension following traumatic brain injury (TBI) is a severe condition that requires potentially harmful treatment strategies such as barbiturate coma. However, the use of barbiturates may be restricted due to concerns about inducing multiorgan system complications related to the therapy. The purpose of this study was to evaluate the outcome and occurrence of treatment-related complications to barbiturate coma treatment in children with refractory intracranial hypertension (RICH) due to TBI in a modern multimodality neurointensive care unit (NICU).

METHODS

The authors conducted a retrospective cohort study of 21 children ≤ 16 years old who were treated in their NICU between 2005 and 2015 with barbiturate coma for RICH following TBI. Demographic and clinical data were acquired from patient records and physiological data from digital monitoring system files.

RESULTS

The median age of these 21 children was 14 years (range 2-16 years) and at admission the median Glasgow Coma Scale score was 7 (range 4-8). Barbiturate coma treatment was added due to RICH at a median of 46 hours from trauma and had a median duration of 107 hours. The onset of barbiturate coma resulted in lower ICP values, lower pulse amplitudes on the ICP curve, and decreased amount of A-waves. No major disturbances in blood gases, liver and kidney function, or secondary insults were observed during this period. Outcome 1 year later revealed a median Glasgow Outcome Scale score of 5 (good recovery), however on the King's Outcome Scale for Childhood Head Injury, the median was 4a (moderate disability).

CONCLUSIONS

The results of this study indicate that barbiturate coma, when used in a modern NICU, is an effective means of lowering ICP without causing concomitant severe side effects in children with RICH and was compatible with good long-term outcome.

Magnetic Resonance Imaging Pilot Study of Intravenous Glyburide in Traumatic Brain Injury

Pre-clinical studies of traumatic brain injury (TBI) show that glyburide reduces edema and hemorrhagic progression of contusions. We conducted a small Phase II, three-institution, randomized placebo-controlled trial of subjects with TBI to assess the safety and efficacy of intravenous (IV) glyburide. Twenty-eight subjects were randomized and underwent a 72-h infusion of IV glyburide or placebo, beginning within 10 h of trauma. Of the 28 subjects, 25 had Glasgow Coma Scale (GCS) scores of 6-10, and 14 had contusions. There were no differences in adverse events (AEs) or severe adverse events (ASEs) between groups. The magnetic resonance imaging (MRI) percent change at 72-168 h from screening/baseline was compared between the glyburide and placebo groups. Analysis of contusions (7 per group) showed that lesion volumes (hemorrhage plus edema) increased 1036% with placebo versus 136% with glyburide (p = 0.15), and that hemorrhage volumes increased 11.6% with placebo but decreased 29.6% with glyburide (p = 0.62). Three diffusion MRI measures of edema were quantified: mean diffusivity (MD), free water (FW), and tissue MD (MDt), corresponding to overall, extracellular, and intracellular water, respectively. The percent change with time for each measure was compared in lesions (n = 14) versus uninjured white matter (n = 24) in subjects receiving placebo (n = 20) or glyburide (n = 18). For placebo, the percent change in lesions for all three measures was significantly different compared with uninjured white matter (analysis of variance [ANOVA], p < 0.02), consistent with worsening of edema in untreated contusions. In contrast, for glyburide, the percent change in lesions for all three measures was not significantly different compared with uninjured white matter. Further study of IV glyburide in contusion TBI is warranted.

Management of moderate and severe traumatic brain injury

Traumatic brain injury (TBI) is a common disorder with high morbidity and mortality, accounting for one in every three deaths due to injury. Older adults are especially vulnerable. They have the highest rates of TBI-related hospitalization and death. There are about 2.5 to 6.5 million US citizens living with TBI-related disabilities. The cost of care is very high. Aside from prevention, little can be done for the initial primary injury of neurotrauma. The tissue damage incurred directly from the inciting event, for example, a blow to the head or bullet penetration, is largely complete by the time medical care can be instituted. However, this event will give rise to secondary injury, which consists of a cascade of changes on a cellular and molecular level, including cellular swelling, loss of membrane gradients, influx of immune and inflammatory mediators, excitotoxic transmitter release, and changes in calcium dynamics. Clinicians can intercede with interventions to improve outcome in the mitigating secondary injury. The fundamental concepts in critical care management of moderate and severe TBI focus on alleviating intracranial pressure and avoiding hypotension and hypoxia. In addition to these important considerations, mechanical ventilation, appropriate transfusion of blood products, management of paroxysmal sympathetic hyperactivity, using nutrition as a therapy, and, of course, venous thromboembolism and seizure prevention are all essential in the management of moderate to severe TBI patients. These concepts will be reviewed using the recent 2016 Brain Trauma Foundation Guidelines to discuss best practices and identify future research priorities.

A clinical decision rule to predict intracranial hypertension in severe traumatic brain injury

OBJECTIVE

While existing guidelines support the treatment of intracranial hypertension in severe traumatic brain injury (TBI), it is unclear when to suspect and initiate treatment for high intracranial pressure (ICP). The objective of this study was to derive a clinical decision rule that accurately predicts intracranial hypertension.

METHODS

Using Delphi methods, the authors identified a set of potential predictors of intracranial hypertension and a clinical decision rule a priori by consensus among a group of 43 neurosurgeons and intensivists who have extensive experience managing severe TBI without ICP monitoring. To validate these predictors, the authors used data from a Latin American trial (n = 150; BEST TRIP). To report on the performance of the rule, they calculated sensitivity, specificity, and positive and negative predictive values with 95% confidence intervals. In a secondary analysis, the rule was validated using data from a North American trial (n = 131; COBRIT).

RESULTS

The final predictors and the clinical decision rule were approved by 97% of participants in the consensus working group. The predictors are divided into major and minor criteria. High ICP would be considered suspected in the presence of 1 major or ≥ 2 minor criteria. Major criteria are: compressed cisterns (CT classification of Marshall diffuse injury [DI] III), midline shift > 5 mm (Marshall DI IV), or nonevacuated mass lesion. Minor criteria are: Glasgow Coma Scale (GCS) motor score ≤ 4, pupillary asymmetry, abnormal pupillary reactivity, or Marshall DI II. The area under the curve for the logistic regression model that contains all the predictors was 0.86. When high ICP was defined as > 22 mm Hg, the decision rule performed with a sensitivity of 93.9% (95% CI 85.0%-98.3%), a specificity of 42.3% (95% CI 31.7%-53.6%), a positive predictive value of 55.5% (95% CI 50.7%-60.2%), and a negative predictive value of 90% (95% CI 77.1%-96.0%). The sensitivity of the clinical decision rule improved with higher ICP cutoffs up to a sensitivity of 100% when intracranial hypertension was defined as ICP > 30 mm Hg. Similar results were found in the North American cohort.

CONCLUSIONS

A simple clinical decision rule based on a combination of clinical and imaging findings was found to be highly sensitive in distinguishing patients with severe TBI who would suffer intracranial hypertension. It could be used to identify patients who require ICP monitoring in high-resource settings or start ICP-lowering treatment in environments where resource limitations preclude invasive monitoring.Clinical trial registration no.: NCT02059941 (clinicaltrials.gov).

Developing a personalized closed-loop controller of medically-induced coma in a rodent model

OBJECTIVE

Personalized automatic control of medically-induced coma, a critical multi-day therapy in the intensive care unit, could greatly benefit clinical care and further provide a novel scientific tool for investigating how the brain response to anesthetic infusion rate changes during therapy. Personalized control would require real-time tracking of inter- and intra-subject variabilities in the brain response to anesthetic infusion rate while simultaneously delivering the therapy, which has not been achieved. Current control systems for medically-induced coma require a separate offline model fitting experiment to deal with inter-subject variabilities, which would lead to therapy interruption. Removing the need for these offline interruptions could help facilitate clinical feasbility. In addition, current systems do not track intra-subject variabilities. Tracking intra-subject variabilities is essential for studying whether or how the brain response to anesthetic infusion rate changes during therapy. Further, such tracking could enhance control precison and thus help facilitate clinical feasibility.

APPROACH

Here we develop a personalized closed-loop anesthetic delivery (CLAD) system in a rodent model that tracks both inter- and intra-subject variabilities in real time while simultaneously controlling the anesthetic in closed loop. We tested the CLAD in rats by administrating propofol to control the electroencephalogram (EEG) burst suppression. We first examined whether the CLAD can remove the need for offline model fitting interruption. We then used the CLAD as a tool to study whether and how the brain response to anesthetic infusion rate changes as a function of changes in the depth of medically-induced coma. Finally, we studied whether the CLAD can enhance control compared with prior systems by tracking intra-subject variabilities.

MAIN RESULTS

The CLAD precisely controlled the EEG burst suppression in each rat without performing offline model fitting experiments. Further, using the CLAD, we discovered that the brain response to anesthetic infusion rate varied during control, and that these variations correlated with the depth of medically-induced coma in a consistent manner across individual rats. Finally, tracking these variations reduced control bias and error by more than 70% compared with prior systems.

SIGNIFICANCE

This personalized CLAD provides a new tool to study the dynamics of brain response to anesthetic infusion rate and has significant implications for enabling clinically-feasible automatic control of medically-induced coma.

Management of Intracranial Pressure: Part I: Pharmacologic Interventions

Dangerous, sustained elevation in intracranial pressure (ICP) is a risk for any patient following severe brain injury. Intracranial pressure elevations that do not respond to initial management are considered refractory to treatment, or rICP. Patients are at significant risk of secondary brain injury and permanent loss of function resulting from rICP. Both nonpharmacologic and pharmacologic interventions are utilized to intervene when a patient experiences either elevation in ICP or rICP. In part 1 of this 2-part series, pharmacologic interventions are discussed. Opioids, sedatives, osmotic diuretics, hypertonic saline solutions, and barbiturates are drug classes that may be used in an attempt to normalize ICP and prevent secondary injury. Nursing care of these patients includes collaboration with an interprofessional team and is directed toward patient and family comfort. The utilization of an evidence-based guideline for the management of rICP is strongly encouraged to improve patient outcomes.

Emergency Neurological Life Support: Intracranial Hypertension and Herniation

Sustained intracranial hypertension and acute brain herniation are "brain codes," signifying catastrophic neurological events that require immediate recognition and treatment to prevent irreversible injury and death. As in cardiac arrest, a brain code mandates the organized implementation of a stepwise management algorithm. The goal of this Emergency Neurological Life Support protocol is to implement an evidence-based, standardized approach to the evaluation and management of patients with intracranial hypertension and/or herniation.

Critical thresholds for intracranial pressure vary over time in non-craniectomised traumatic brain injury patients

Background

Intracranial pressure (ICP)- and cerebral perfusion pressure (CPP)-guided therapy is central to neurocritical care for traumatic brain injury (TBI) patients. We sought to identify time-dependent critical thresholds for mortality and unfavourable outcome for ICP and CPP in non-craniectomised TBI patients.

Methods

This is a retrospective cohort study of 355 patients with moderate-to-severe TBI who received ICP monitoring and were managed without decompressive craniectomy in a tertiary hospital neurocritical care unit. Patients were grouped in 2 × 2 tables according to survival/death or favourable/unfavourable outcomes at 6 months and serial thresholds of mean ICP and CPP, using increments of 0.1 and 0.5 mmHg respectively. Sequential chi-square analysis was performed, and the thresholds yielding the highest chi-square test statistic were taken as having the best discriminative value for outcome. This process was repeated over monitoring periods of 1, 3, 5 and 7 days and for each day of recording to establish time-dependent thresholds. The same analysis was performed for age and sex subgroups.

Results

Global ICP thresholds were 21.3 and 20.5 mmHg for mortality and unfavourable outcome respectively (p < 0.001). After the first day of ICP monitoring, ICP thresholds fell to between 15 and 20 mmHg and remained significant (p < 0.05). Significant time-dependent CPP thresholds for mortality or unfavourable outcome were often not identified, and no identifiable trends were produced.

Conclusion

Critical ICP thresholds in non-craniectomised TBI patients vary with time and fall below established ICP targets after the first day of monitoring.

Electronic supplementary material

The online version of this article (10.1007/s00701-018-3555-3) contains supplementary material, which is available to authorized users.

Antiepileptic drugs in critically ill patients

BACKGROUND

The incidence of seizures in intensive care units ranges from 3.3% to 34%. It is therefore often necessary to initiate or continue anticonvulsant drugs in this setting. When a new anticonvulsant is initiated, drug factors, such as onset of action and side effects, and patient factors, such as age, renal, and hepatic function, should be taken into account. It is important to note that the altered physiology of critically ill patients as well as pharmacological and nonpharmacological interventions such as renal replacement therapy, extracorporeal membrane oxygenation, and target temperature management may lead to therapeutic failure or toxicity. This may be even more challenging with the availability of newer antiepileptics where the evidence for their use in critically ill patients is limited.

MAIN BODY

This article reviews the pharmacokinetics and pharmacodynamics of antiepileptics as well as application of these principles when dosing antiepileptics and monitoring serum levels in critically ill patients. The selection of the most appropriate anticonvulsant to treat seizure and status epileptics as well as the prophylactic use of these agents in this setting are also discussed. Drug-drug interactions and the effect of nonpharmacological interventions such as renal replacement therapy, plasma exchange, and extracorporeal membrane oxygenation on anticonvulsant removal are also included.

CONCLUSION

Optimal management of antiepileptic drugs in the intensive care unit is challenging given altered physiology, polypharmacy, and nonpharmacological interventions, and requires a multidisciplinary approach where appropriate and timely assessment, diagnosis, treatment, and monitoring plans are in place.

Intracranial pressure in patients undergoing decompressive craniectomy: new perspective on thresholds

OBJECTIVE

Decompressive craniectomy (DC) is an established part of treatment in patients suffering from malignant infarction of the middle cerebral artery (MCA) or traumatic brain injury (TBI). However, no clear evidence for intracranial pressure (ICP)-guided therapy after DC exists. The lack of this evidence might be due to the frequently used, but simplified threshold for ICP of 20 mm Hg, which determines further therapy. Therefore, the objective of this study was to evaluate this threshold's accuracy and to investigate the course of ICP values with respect to neurological outcome.

METHODS

Data on clinical characteristics and parameters of the ICP course on the intensive care unit were collected retrospectively in 102 patients who underwent DC between December 2007 and April 2014 at the authors' institution. The postoperative ICP course in the first 168 hours was recorded and analyzed. From these findings, ICP thresholds discriminating favorable from unfavorable outcome were calculated using conditional inference tree analysis. Additionally, survival analysis was performed using the Kaplan-Meier method. Prognostic factors were assessed via univariate analysis and multivariate logistic regression. Favorable outcome was defined as a score of 0–4 on the modified Rankin Scale.

RESULTS

Multivariate logistic regression revealed that anisocoria, diagnosis, and ICP values differed significantly between the outcome groups. ICP values in the favorable and unfavorable outcome groups differed significantly (p < 0.001), while the mean ICP of both groups lay below the limit of 20 mm Hg (17.5 and 11.5 mm Hg, respectively). These findings were reproduced when analyzing the underlying pathologies of TBI and MCA infarction separately. Based on these findings, optimized time-dependent threshold values were calculated and found to be between 10 and 17 mm Hg. These values significantly distinguished favorable from unfavorable outcome and predicted 30-day mortality (p < 0.001).

CONCLUSIONS

This study systematically evaluated ICP levels in a long-term analysis after DC and provides new, surprisingly low, time-dependent ICP thresholds for these patients. Future trials investigating the benefit of ICP-guided therapy should take these thresholds into consideration and validate them in further patient cohorts.

Hypertonic saline infusion for treating intracranial hypertension after severe traumatic brain injury

Traumatic brain injury (TBI) remains a major cause of mortality and disability. Post-traumatic intracranial hypertension (ICH) further complicates the care of patients. Hyperosmolar agents are recommended for the treatment of ICH, but no consensus or high-level data exist on the use of any particular agent or the route of administration. The two agents used commonly are hypertonic saline (HTS) and mannitol given as bolus therapy. Smaller studies suggest that HTS may be a superior agent in reducing the ICH burden, but neither agent has been shown to improve mortality or functional outcome. In a recently published analysis of pooled data from three prospective clinical trials, continuous infusion of HTS correlated with serum hypernatremia and reduced ICH burden in addition to improving 90-day mortality and functional outcome. This lays the foundation for the upcoming continuous hyperosmolar therapy for traumatic brain-injured patients (COBI) randomized controlled trial to study the outcome benefit of continuous HTS infusion to treat ICH after severe TBI. This is much anticipated and will be a high impact trial should the results be replicated. However, this would still leave a question over the use of mannitol bolus therapy which will need to be studied.

[Correlation of intracranial pressure and diameter of the sheath of the optic nerve by computed tomography in severe traumatic brain injury]

BACKGROUND

Noninvasive techniques to evaluate intracranial pressure (ICP) are important for everyday practice in intensive care and neurosurgery departments. CT data can be used to evaluate the optic nerve sheath diameter (ONSD) and, indirectly, the ICP value. The ONSD value is an additional criterion in deciding on invasive monitoring of ICP.

AIM

To analyze a correlation between CT-based ONSD and the results of invasive measurements of ICP in patients with severe traumatic brain injury.

MATERIAL AND METHODS

The study evaluated 41 patients with severe traumatic brain injury within the first 48 h after injury. Invasive monitoring of ICP (Codman & Shurtlett, MA, USA) was performed during 7±1.7 days. ONSD was measured using axial CT scans (CereTom, Neurologica Danvers, MA, USA) with a slice thickness of 2.5 mm. The ONSD value was measured at a distance of 3 mm from the posterior eyeball contour. The patients were allocated in a group with normal ICP (10 patients) and a group with high ICP (31 patients). ONSD served as an ICP classifier. The data were processed using ROC analysis.

RESULTS

According to the CT data, the optimal threshold ONSD value was 6.35 mm in patients in the acute TBI period. The sensitivity was 0.93 (95% СI 0.84-1.00), the specificity was 0.80 (95% СI 0.50-1.00), and AUC was 0.87 (95% СI 0.69-1.00).

CONCLUSION

We found a correlation between the CT-based ONSD and the median ICP (R=0.32, p<0.05). An ONSD value of 6.35 mm and more is one of the signs of previous or existing ICP.

ICP management in patients suffering from traumatic brain injury: a systematic review of randomized controlled trials

BACKGROUND

Severe traumatic brain injury (sTBI) is a major cause of morbidity and mortality. Intracranial pressure (ICP) monitoring and management form the cornerstone of treatment paradigms for sTBI in developed countries. We examine the available randomized controlled trial (RCT) data on the impact of ICP management on clinical outcomes after sTBI.

METHODS

A systematic review of the literature on ICP management following sTBI was performed to identify pertinent RCT articles.

RESULTS

We identified six RCT articles that examined whether ICP monitoring, decompressive craniectomy, or barbiturate coma improved clinical outcomes after sTBI. These studies support (1) the utility of ICP monitoring in the management of sTBI patients and (2) craniectomy and barbiturate coma as effective methods for the management of intracranial hypertension secondary to sTBI. However, despite adequate ICP control in sTBI patients, a significant proportion of surviving patients remain severely disabled.

CONCLUSIONS

If one sets the bar at the level of functional independence, then the RCT data raises questions pertaining to the utility of decompressive craniectomy and barbiturate coma in the setting of sTBI.

Management of Traumatic Brain Injury

Traumatic brain injury remains a serious public health problem, causing death and disability for millions. In order to maximize outcomes in the face of a complex injury to a complex organ, a variety of advanced neuromonitoring techniques may be used to guide surgical and medical decision-making. Because of the heterogeneity of injury types and the plethora of treatment confounders present in this patient population, the scientific study of specific interventions is challenging. This challenge highlights the need for a firm understanding of the anatomy and pathophysiology of brain injuries when making clinical decisions in the intensive care unit.

Acute Management of Traumatic Brain Injury

Traumatic brain injury (TBI) is a leading cause of death and disability in patients with trauma. Management strategies must focus on preventing secondary injury by avoiding hypotension and hypoxia and maintaining appropriate cerebral perfusion pressure (CPP), which is a surrogate for cerebral blood flow. CPP can be maintained by increasing mean arterial pressure, decreasing intracranial pressure, or both. The goal should be euvolemia and avoidance of hypotension. Other factors that deserve important consideration in the acute management of patients with TBI are venous thromboembolism, stress ulcer, and seizure prophylaxis, as well as nutritional and metabolic optimization.

A Comparison of Pharmacologic Therapeutic Agents Used for the Reduction of Intracranial Pressure After Traumatic Brain Injury

OBJECTIVE

In neurotrauma care, a better understanding of treatments after traumatic brain injury (TBI) has led to a significant decrease in morbidity and mortality in this population. TBI represents a significant medical problem, and complications after TBI are associated with the initial injury and postevent intracranial processes such as increased intracranial pressure and brain edema. Consequently, appropriate therapeutic interventions are required to reduce brain tissue damage and improve cerebral perfusion. We present a contemporary review of literature on the use of pharmacologic therapies to reduce intracranial pressure after TBI and a comparison of their efficacy.

METHODS

This review was conducted by PubMed query. Only studies discussing pharmacologic management of patients after TBI were included. This review includes prospective and retrospective studies and includes randomized controlled trials as well as cohort, case-control, observational, and database studies. Systematic literature reviews, meta-analyses, and studies that considered conditions other than TBI or pediatric populations were not included.

RESULTS

Review of the literature describing the current pharmacologic treatment for intracranial hypertension after TBI most often discussed the use of hyperosmolar agents such as hypertonic saline and mannitol, sedatives such as fentanyl and propofol, benzodiazepines, and barbiturates. Hypertonic saline is associated with faster resolution of intracranial hypertension and restoration of optimal cerebral hemodynamics, although these advantages did not translate into long-term benefits in morbidity or mortality. In patients refractory to treatment with hyperosmolar therapy, induction of a barbiturate coma can reduce intracranial pressure, although requires close monitoring to prevent adverse events.

CONCLUSIONS

Current research suggests that the use of hypertonic saline after TBI is the best option for immediate decrease in intracranial pressure. A better understanding of the efficacy of each treatment option can help to direct treatment algorithms during the critical early hours of trauma care and continue to improve morbidity and mortality after TBI.

Applicability of NeuroTrend as a bedside monitor in the neuro ICU

OBJECTIVE

To assess whether ICU caregivers can correctly read and interpret continuous EEG (cEEG) data displayed with the computer algorithm NeuroTrend (NT) with the main attention on seizure detection and determination of sedation depth.

METHODS

120 screenshots of NT (480h of cEEG) were rated by 18 briefly trained nurses and biomedical analysts. Multirater agreements (MRA) as well as interrater agreements (IRA) compared to an expert opinion (EXO) were calculated for items such as pattern type, pattern location, interruption of recording, seizure suspicion, consistency of frequency, seizure tendency and level of sedation.

RESULTS

MRA as well as IRA were almost perfect (80-100%) for interruption of recording, spike-and-waves, rhythmic delta activity and burst suppression. A substantial agreement (60-80%) was found for electrographic seizure patterns, periodic discharges and seizure suspicion. Except for pattern localization (70.83-92.26%), items requiring a precondition and especially those who needed interpretation like consistency of frequency (47.47-79.15%) or level of sedation (41.10%) showed lower agreements.

CONCLUSIONS

The present study demonstrates that NT might be a useful bedside monitor in cases of subclinical seizures. Determination of correct sedation depth by ICU caregivers requires a more detailed training.

SIGNIFICANCE

Computer algorithms may reduce the workload of cEEG analysis in ICU patients.

Reconsidering the role of decompressive craniectomy for neurological emergencies

OBJECTIVE

There is little doubt that decompressive craniectomy can reduce mortality. However, there is concern that any reduction in mortality comes at an increase in the number of survivors with severe neurological disability.

METHOD

Over the past decade there have been several randomised controlled trials comparing surgical decompression with standard medical therapy in the context of ischaemic stroke and severe traumatic brain injury. The results of each trial are evaluated.

RESULTS

There is now unequivocal evidence that a decompressive craniectomy reduces mortality in the context of "malignant" middle infarction and following severe traumatic brain injury. However, it has only been possible to demonstrate an improvement in outcome by categorizing a mRS of 4 and upper severe disability as favourable outcome. This is contentious and an alternative interpretation is that surgical decompression reduces mortality but exposes a patient to a greater risk of survival with severe disability.

CONCLUSION

It would appear unlikely that further randomised controlled trials will be possible given the significant reduction in mortality achieved by surgical decompression. It may be that observational cohort studies and outcome prediction models may provide data to determine those patients most likely to benefit from surgical decompression.

Acute Management of Moderate-Severe Traumatic Brain Injury

Traumatic brain injury (TBI) continues to be a major public health problem. Proposed treatments have not withstood testing in clinical trials because of failure to account for different types of TBI and other weaknesses in trial design. Management goals continue to be prevention and prompt treatment of secondary insults (hypotension, hypoxia, and other physiologic derangements). This goal is best accomplished by careful attention to airway, breathing, circulation, and basic principles of intensive care unit management. Attempts to intervene prophylactically to prevent intracranial hypertension or other complications have not been beneficial and may even have deleterious effects.

A Fatal Adverse Effect of Barbiturate Coma Therapy: Dyskalemia

The management guideline for traumatic brain injury (TBI) recommends high-dose barbiturate therapy to control increased intracranial pressure refractory to other therapeutic options. High-dose barbiturate therapy, however, may cause many severe side effects; the commonly recognized ones include hypotension, immunosuppression, hepatic dysfunction, renal dysfunction, and prolonged decrease of cortical activity. Meanwhile, dyskalemia remains relatively uncommon. In this study, we report the case of a hypokalemic patient with severe rebound hyperkalemia, which occurred as a result of barbiturate coma therapy administered for TBI treatment.

Emergency Neurological Life Support: Intracranial Hypertension and Herniation

Sustained intracranial hypertension and acute brain herniation are "brain codes," signifying catastrophic neurological events that require immediate recognition and treatment to prevent irreversible injury and death. As in cardiac arrest, a brain code mandates the organized implementation of a stepwise management algorithm. The goal of this emergency neurological life support protocol is to implement an evidence-based, standardized approach to the evaluation and management of patients with intracranial hypertension and/or herniation.