Guidelines for the management of severe traumatic brain injury. VIII. Intracranial pressure thresholds

Optic nerve sheath diameter and eyeball transverse diameter in severe head injury and its correlation with intracranial pressure

BACKGROUND

Gold standard for determining intracranial pressure (ICP), intraventricular catheter, is invasive with associated risks. Non-invasive investigations like magnetic resonance imaging and ultrasonography have demonstrated correlation between optic nerve sheath diameter (ONSD) and raised ICP. However, computed tomography (CT) is accessible and less operator-dependent. Literature shows variable results regarding correlations between ICP and ONSD on CT. The study aimed to investigate correlations between raised ICP and ONSD, eyeball transverse diameter (ETD), and ONSD/ETD ratios on CT scan(s) of severe head injuries.

METHODS

A retrospective review of a three-year prospectively-maintained database of severe traumatic head injuries in patients who had ICP measurements and CT scans was conducted. Glasgow Coma Score (GCS), ICP, ONSD 3 mm and 9 mm behind the globe, ETD, ONSD/ETD ratios, CT Marshall Grade, and Glasgow Outcome Score (GOS) were recorded. Statistical analysis assessed correlations between ICP and CT measurements.

RESULTS

Seventy-four patients were assessed; mortality rate: 36.5 %. Assault (48.6 %) and pedestrian-vehicle collisions (21.6 %) were the most common mechanisms. CT Marshall Grade correlated significantly with 3 mm and 9 mm ONSD, ONSD/ETD ratios, GCS, and GCS motor score, which correlated significantly with GOS. No significant correlation was found between ICP and ONSD, ETD or ONSD/ETD ratios. Marshall Grade was not significantly associated with ICP measurements but correlated with injury severity.

CONCLUSIONS

Unlike previous studies, our study not only investigated the correlation between ICP and single variables (ONSD and ETD) but also the ONSD/ETD ratios. No correlations were observed between raised ICP and ONSD, ETD or ONSD/ETD ratio on CT in neurotrauma patients.

Weekend Admission and Mortality in Patients With Traumatic Brain Injury: A Meta-analysis

Objective

Previous studies have reported the presence of a "weekend effect" with respect to mortality in serious emergency admissions, including cases of traumatic brain injury (TBI). However, the relationship between weekend hospitalization and TBI mortality has not been fully established. This study aimed to conduct a systematic review of available evidence and investigate differences in mortality among TBI patients between weekday and weekend admissions.

Methods

Electronic databases including PubMed, Cochrane Library, and Embase were used to obtain relevant articles. Mortality, as the primary outcome of interest, encompassed in-hospital or 30-day mortality. Mortality rates were compared between the 2 groups, weekend and weekday admissions. Additionally, meta-regression analysis was performed on potential confounders to verify and provide comparative results.

Results

A total of 7 studies involving 522,942 TBI patients were eligible for inclusion in the synthesis of the systematic review. Of these patients, 71.6% were admitted during weekdays, whereas 28.4% were hospitalized on weekends. The overall integrated mortality was 11.0% (57,286/522,942), with a mortality rate of 10.8% in the weekday group and 11.3% in the weekend group. Pooled analysis revealed no significant difference in mortality between the weekday and weekend groups (risk ratio, 0.99; 95% confidence interval, 0.90-1.09; p=0.78). Furthermore, the meta-regression analysis for sensitivity assessment showed no modifying effect on mortality (p=0.79).

Conclusion

This study found no difference in mortality rates between weekday and weekend admissions among TBI patients. Additional sensitivity analyses also demonstrated no significant increase in the risk of mortality in the weekend group.

Early brain metabolic disturbances associated with delayed cerebral ischemia in patients with severe subarachnoid hemorrhage

Delayed cerebral ischemia (DCI) is a devastating complication of aneurysmal subarachnoid hemorrhage (ASAH) causing brain infarction and disability. Cerebral microdialysis (CMD) monitoring is a focal technique that may detect DCI-related neurochemical changes as an advance warning. We conducted retrospective analyses from 44 poor-grade ASAH patients and analyzed glucose, lactate, pyruvate, and glutamate concentrations in control patients without DCI (n = 19), and in patients with DCI whose CMD probe was located within (n = 17) or outside (n = 8) a new infarct. When monitored from within a lesion, DCI was preceded by a decrease in glucose and a surge in glutamate, accompanied by increases in lactate/pyruvate and lactate/glucose ratios whereas these parameters remained stable in control patients. When CMD monitoring was performed outside the lesion, the glutamate surge was absent, but glucose and L/G ratio were still significantly altered. Overall, glucose and L/G ratio were significant biomarkers of DCI (se96.0, spe73.7-68.4). Glucose and L/G predicted DCI 67 h before CT detection of a new infarct. The pathogenesis of DCI therefore induces early metabolic disturbances that can be detected by CMD as an advance warning. Glucose and L/G could provide a trigger for initiating further examination or therapy, earlier than when guided by other monitoring techniques.

Study protocol for a multicenter randomized controlled pilot study on decompressive laparotomy vs. decompressive craniectomy for intractable intracranial pressure after traumatic brain injury: The SCALPEL study

Introduction

Decompressive craniectomy (DC) is the ultimate intervention to lower intracranial pressure (ICP) following severe traumatic brain injury (TBI). However, this intervention is associated with considerable adverse events and a higher proportion of survivors with poor functional outcomes.

Research question

In a multicompartment system ICP is associated with intraabdominal pressure (IAP) due to cerebral venous outflow from the brain. This is the rationale for decompressive laparotomy (DL) to control ICP after TBI as reported by experimental and retrospective clinical data. The safety profile of DL is superior to DC. This study aims to randomly assign patients with intractable high ICP after severe TBI to DL or DC.

Material and methods

Among other inclusion criteria, ICP must be above 20 mmHg (1-12 h) despite sedation and all other measures according to current guidelines. The primary outcome is the Extended Glasgow Outcome Scale assessed after twelve months. Further secondary outcome measures are compartmental pressure values, complications, etc. After 20 initial patients, results will be reviewed by the ethics committees and safety monitoring board to decide on the enrolment of 80 additional patients.

Results

The study is designed to provide not only high-quality prospective data for the first time on this treatment approach, its two-stage design (20 + 80 pts) also provides maximum patient safety. This protocol conforms with the SPIRIT 2013 Statement. Ethics approval was granted by our but also 5 other university ethics committees (registration 473/18S).

Conclusion

Registration was performed prior to study initiation in November 2021 (registration number NCT05115929).

Multimodal and autoregulation monitoring in the neurointensive care unit

Given the complexity of cerebral pathology in patients with acute brain injury, various neuromonitoring strategies have been developed to better appreciate physiologic relationships and potentially harmful derangements. There is ample evidence that bundling several neuromonitoring devices, termed "multimodal monitoring," is more beneficial compared to monitoring individual parameters as each may capture different and complementary aspects of cerebral physiology to provide a comprehensive picture that can help guide management. Furthermore, each modality has specific strengths and limitations that depend largely on spatiotemporal characteristics and complexity of the signal acquired. In this review we focus on the common clinical neuromonitoring techniques including intracranial pressure, brain tissue oxygenation, transcranial doppler and near-infrared spectroscopy with a focus on how each modality can also provide useful information about cerebral autoregulation capacity. Finally, we discuss the current evidence in using these modalities to support clinical decision making as well as potential insights into the future of advanced cerebral homeostatic assessments including neurovascular coupling.

The intracranial compartmental syndrome: a proposed model for acute brain injury monitoring and management

For decades, one of the main targets in the management of severe acute brain injury (ABI) has been intracranial hypertension (IH) control. However, the determination of IH has suffered variations in its thresholds over time without clear evidence for it. Meanwhile, progress in the understanding of intracranial content (brain, blood and cerebrospinal fluid) dynamics and recent development in monitoring techniques suggest that targeting intracranial compliance (ICC) could be a more reliable approach rather than guiding actions by predetermined intracranial pressure values. It is known that ICC impairment forecasts IH, as intracranial volume may rapidly increase inside the skull, a closed bony box with derisory expansibility. Therefore, an intracranial compartmental syndrome (ICCS) can occur with deleterious brain effects, precipitating a reduction in brain perfusion, thereby inducing brain ischemia. The present perspective review aims to discuss the ICCS concept and suggest an integrative model for the combination of modern invasive and noninvasive techniques for IH and ICC assessment. The theory and logic suggest that the combination of multiple ancillary methods may enhance ICC impairment prediction, pointing proactive actions and improving patient outcomes.

National Follow-up Survey of Preventable Trauma Death Rate in Korea

BACKGROUND

The preventable trauma death rate survey is a basic tool for the quality management of trauma treatment because it is a method that can intuitively evaluate the level of national trauma treatment. We conducted this study as a national biennial follow-up survey project and report the results of the review of the 2019 trauma death data in Korea.

METHODS

From January 1, 2019 to December 31, 2019, of a total of 8,482 trauma deaths throughout the country, 1,692 were sampled from 279 emergency medical institutions in Korea. All cases were evaluated for preventability of death and opportunities for improvement using a multidisciplinary panel review approach.

RESULTS

The preventable trauma death rate was estimated to be 15.7%. Of these, 3.1% were judged definitive preventable deaths, and 12.7% were potentially preventable deaths. The odds ratio for preventable traumatic death was 2.56 times higher in transferred patients compared to that of patients who visited the final hospital directly. The group that died 1 hour after the accident had a statistically significantly higher probability of preventable death than that of the group that died within 1 hour after the accident.

CONCLUSION

The preventable trauma death rate for trauma deaths in 2019 was 15.7%, which was 4.2%p lower than that in 2017. To improve the quality of trauma treatment, the transfer of severe trauma patients to trauma centers should be more focused.

Intracranial pressure: current perspectives on physiology and monitoring

Intracranial pressure (ICP) monitoring is now viewed as integral to the clinical care of many life-threatening brain insults, such as severe traumatic brain injury, subarachnoid hemorrhage, and malignant stroke. It serves to warn of expanding intracranial mass lesions, to prevent or treat herniation events as well as pressure elevation which impedes nutrient delivery to the brain. It facilitates the calculation of cerebral perfusion pressure (CPP) and the estimation of cerebrovascular autoregulatory status. Despite advancements in our knowledge emanating from a half century of experience with this technology, important controversies remain related even to fundamental aspects of ICP measurements, including indications for monitoring, ICP treatment thresholds, and management of intracranial hypertension. Here, we review the history of ICP monitoring, the underlying pathophysiology as well as current perspectives on why, when and how ICP monitoring is best used. ICP is typically assessed invasively but a number of emerging, non-invasive technologies with inherently lower risk are showing promise. In selected cases, additional neuromonitoring can be used to assist in the interpretation of ICP monitoring information and adapt directed treatment accordingly. Additional efforts to expand the evidence base relevant to ICP monitoring, related technologies and management remain a high priority in neurosurgery and neurocritical care.

Traumatic brain injury in the new millennium: new population and new management

INTRODUCTION

Traumatic brain injury (TBI) is one of the leading causes of death and disability globally. We present a study describing epidemiological changes in severe TBI and the impact these changes have had on management and analysing alternatives that may improve outcomes in this new population.

MATERIALS AND METHODS

We performed a retrospective, descriptive, cross-sectional analysis of patients presenting severe TBI at our hospital in the period of 1992-1996 and 2009-2013. We analysed demographic data, including age, sex, mortality, aetiology, anticoagulation, treatment, and functional outcome.

RESULTS

We reviewed data from 220 patients. In the second cohort, there were 40% fewer patients, mean age was 12 years older, patients were more frequently receiving anticoagulation therapy, and the percentage of interventions was halved. Aetiology varied, with traffic accidents being the main cause in the first group, and accidental falls and being hit by cars in the second group. There were no intergroup differences for mortality or functional outcomes.

CONCLUSION

The age of patients admitted due to severe TBI has increased. As a result of this, the main cause of severe TBI in our population is accidental falls in elderly, anticoagulated patients. Despite the low-energy nature of trauma, patients in the second cohort presented a poorer baseline status, and were less frequently eligible for surgery, with no improvement in mortality or functional outcomes.

Traumatic brain injury in the new millennium: A new population and new management

INTRODUCTION

Traumatic brain injury (TBI) is one of the leading causes of death and disability globally. We present a study describing epidemiological changes in severe TBI and the impact these changes have had on management and analysing alternatives that may improve outcomes in this new population.

MATERIALS AND METHODS

We performed a retrospective, descriptive, cross-sectional analysis of patients presenting severe TBI at our hospital in the period of 1992-1996 and 2009-2013. We analysed demographic data, including age, sex, mortality, aetiology, anticoagulation, treatment, and functional outcome.

RESULTS

We reviewed data from 220 patients. In the second cohort, there were 40% fewer patients, mean age was 12years older, patients were more frequently receiving anticoagulation therapy, and the percentage of interventions was halved. Aetiology varied, with traffic accidents being the main cause in the first group, and accidental falls and being hit by cars in the second group. There were no intergroup differences for mortality or functional outcomes.

CONCLUSION

The age of patients admitted due to severe TBI has increased. As a result of this, the main cause of severe TBI in our population is accidental falls in elderly, anticoagulated patients. Despite the low-energy nature of trauma, patients in the second cohort presented a poorer baseline status, and were less frequently eligible for surgery, with no improvement in mortality or functional outcomes.

Group-based trajectory modeling of intracranial pressure in patients with acute brain injury: Results from multi-center ICUs, 2008-2019

Objective

The objective of the study was to characterize the longitudinal, dynamic intracranial pressure (ICP) trajectory in acute brain injury (ABI) patients admitted to intensive care unit (ICU) and explore whether it added sights over traditional thresholds in predicting outcomes.

Methods

ABI patients with ICP monitoring were identified from two public databases named Medical Information Mart for the Intensive Care (MIMIC)‐IV and eICU Collaborative Research Database (eICU‐CRD). Group‐based trajectory modeling (GBTM) was employed to identify 4‐h ICP trajectories in days 0–5 post‐ICU admission. Then, logistic regression was used to compare clinical outcomes across distinct groups. To further validate previously reported thresholds, we created the receiver operating characteristic (ROC) curve in our dataset.

Results

A total of 810 eligible patients were ultimately enrolled in the study. GBTM analyses generated 6 distinct ICP trajectories, differing in the initial ICP, evolution pattern, and number/proportion of spikes >20/22 mmHg. Compared with patients in “the highest, declined then rose” trajectory, those belonging to the “lowest, stable,” “low, stable,” and “medium, stable” ICP trajectories were at lower risks of 30‐day mortality (odds ratio [OR] 0.04; 95% confidence interval [CI] 0.01, 0.21), (OR 0.04; 95% CI 0.01, 0.19), (OR 0.08; 95% CI 0.01, 0.42), respectively. ROC analysis demonstrated an unfavorable result, for example, 30‐day mortality in total cohort: an area under the curve (AUC): 0.528, sensitivity: 0.11, and specificity: 0.94.

Conclusions

This study identified three ICP trajectories associated with elevated risk, three with reduced risks for mortality during ICU hospitalization. Notably, a fixed ICP threshold should not be applied to all kinds of patients. GBTM, a granular method for describing ICP evolution and their association with clinical outcomes, may add to the current knowledge in intracranial hypertension treatment.

Ketamine Boluses Are Associated with a Reduction in Intracranial Pressure and an Increase in Cerebral Perfusion Pressure: A Retrospective Observational Study of Patients with Severe Traumatic Brain Injury

Background

Increased intracranial pressure (ICP) and hypotension have long been shown to lead to worse outcomes in the severe traumatic brain injury (TBI) population. Adequate sedation is a fundamental principle in TBI care, and ketamine is an attractive option for sedation since it does not commonly cause systemic hypotension, whereas most other sedative medications do. We evaluated the effects of ketamine boluses on both ICP and cerebral perfusion pressure (CPP) in patients with severe TBI and refractory ICP.

Methods

We conducted a retrospective review of all patients admitted to the neurointensive care unit at a single tertiary referral center who had a severe traumatic brain injury with indwelling intracranial pressure monitors. We identified those patients with refractory intracranial pressure who received boluses of ketamine. We defined refractory as any sustained ICP greater than 20 mmHg after the patient was adequately sedated, serum Na was at goal, and CO₂ was maintained between 35 and 40 mmHg. The primary outcome was a reduction in ICP with a subsequent increase in CPP.

Results

The patient cohort consisted of 44 patients with a median age of 30 years and a median presenting Glasgow Coma Scale (GCS) of 5. The median reduction in ICP after administration of a ketamine bolus was −3.5 mmHg (IQR −9 to +1), and the postketamine ICP was significantly different from baseline (p < 0.001). Ketamine boluses led to an increase in CPP by 2 mmHg (IQR −5 to +12), which was also significantly different from baseline (p < 0.001).

Conclusion

In this single-institution study of patients with severe traumatic brain injury, ketamine boluses were associated with a reduction in ICP and an increase in CPP. This was a retrospective review of 43 patients and is therefore limited in nature, but further randomized controlled trials should be performed to confirm the findings.

A recurrent machine learning model predicts intracranial hypertension in neurointensive care patients

The evolution of intracranial pressure (ICP) of critically ill patients admitted to a neurointensive care unit (ICU) is difficult to predict. Besides the underlying disease and compromised intracranial space, ICP is affected by a multitude of factors, many of which are monitored on the ICU, but the complexity of the resulting patterns limits their clinical use. This paves the way for new machine learning (ML) techniques to assist clinical management of patients undergoing invasive ICP monitoring independent of the underlying disease. An institutional cohort (ICP-ICU) of patients with invasive ICP monitoring (n = 1346) was used to train recurrent ML models to predict the occurrence of ICP increases of ≥ 22mmHg over a long (> 2 hours) time period in the upcoming hours. External validation was performed on patients undergoing invasive ICP measurement in two publicly available datasets (Medical Information Mart for Intensive Care (MIMIC, n = 998) and eICU Collaborative Research Database (eICU, n = 1634)). Different distances (1h-24 h) between prediction time point and upcoming critical phase were evaluated, demonstrating a decrease in performance but still robust AUC-ROC with larger distances (24 h AUC-ROC: ICP-ICU 0.826 ± 0.0071, MIMIC 0.836 ± 0.0063, eICU 0.779 ± 0.0046, 1 h AUC-ROC: ICP-ICU 0.982 ± 0.0008, MIMIC 0.965 ± 0.0010, eICU 0.941 ± 0.0025). The model operates on sparse hourly data and is stable in handling variable input lengths and missingness through its nature of recurrence and internal memory. Calculation of gradient-based feature importance revealed individual underlying decisions for our Long Short Time Memory (LSTM) based model and thereby provided improved clinical interpretability. Recurrent ML models have the potential to be an effective tool for the prediction of ICP increases with high translational potential.

Big data and predictive analytics in neurocritical care

PURPOSE OF REVIEW

To describe predictive data and workflow in the intensive care unit when managing neurologically ill patients.

RECENT FINDINGS

In the era of Big Data in medicine, intensive critical care units are data-rich environments. Neurocritical care adds another layer of data with advanced multimodal monitoring to prevent secondary brain injury from ischemia, tissue hypoxia, and a cascade of ongoing metabolic events. A step closer toward personalized medicine is the application of multimodal monitoring of cerebral hemodynamics, bran oxygenation, brain metabolism, and electrophysiologic indices, all of which have complex and dynamic interactions. These data are acquired and visualized using different tools and monitors facing multiple challenges toward the goal of the optimal decision support system. In this review, we highlight some of the predictive data used to diagnose, treat, and prognosticate the neurologically ill patients. We describe information management in neurocritical care units including data acquisition, wrangling, analysis, and visualization.

Application of magnetically actuated self-clearing catheter for rapid in situ blood clot clearance in hemorrhagic stroke treatment

Maintaining the patency of indwelling drainage devices is critical in preventing further complications following an intraventricular hemorrhage (IVH) and other chronic disease management. Surgeons often use drainage devices to remove blood and cerebrospinal fluid but these catheters frequently become occluded with hematoma. Using an implantable magnetic microactuator, we created a self-clearing catheter that can generate large enough forces to break down obstructive blood clots by applying time-varying magnetic fields. In a blood-circulating model, our self-clearing catheters demonstrated a > 7x longer functionality than traditional catheters (211 vs. 27 min) and maintained a low pressure for longer periods (239 vs. 79 min). Using a porcine IVH model, the self-clearing catheters showed a greater survival rate than control catheters (86% vs. 0%) over the course of 6 weeks. The treated animals also had significantly smaller ventricle sizes 1 week after implantation compared to the control animals with traditional catheters. Our results suggest that these magnetic microactuator-embedded smart catheters can expedite the removal of blood from the ventricles and potentially improve the outcomes of critical patients suffering from often deadly IVH.

Changes in Blood Pressure and Heart Rate during Decompressive Craniectomy

Objective

Rapid increase in intracranial pressure (ICP) can result in hypertension, bradycardia and apnea, referred to as the Cushing phenomenon. During decompressive craniectomy (DC), rapid ICP decreases can cause changes in mean atrial blood pressure (mABP) and heart rate (HR), which may be an indicator of intact autoregulation and vasomotor reflex.

Methods

A total of 82 patients who underwent DC due to traumatic brain injury (42 cases), hypertensive intracerebral hematoma (19 cases), or major infarction (21 cases) were included in this prospective study. Simultaneous ICP, mABP, and HR changes were monitored in one minute intervals during, prior to and 5–10 minutes following the DC.

Results

After DC, the ICP decreased from 38.1±16.3 mmHg to 9.5±14.2 mmHg (p<0.001) and the mABP decreased from 86.4±14.5 mmHg to 72.5±11.4 mmHg (p<0.001). Conversly, overall HR was no significantly changed in HR, which was 100.1±19.7 rate/min prior to DC and 99.7±18.2 rate/min (p=0.848) after DC. Notably when the HR increased after DC, it correlated with a favorable outcome (p<0.001), however mortality was increased (p=0.032) when the HR decreased or remained unchanged.

Conclusion

In this study, ICP was decreased in all patients after DC. Changes in HR were an indicator of preserved autoregulation and vasomotor reflex. The clinical outcome was improved in patients with increased HR after DC.

Direct Consequences of Cranioplasty to the Brain: Intracranial Pressure Study

ABSTRACT

Intracranial pressure (ICP) is a crucial factor that we need to take into account in all major pathophysiological changes of the brain after decompressive craniectomy (DC) and cranioplasty (CP). The purpose of our study was to check ICP values before and after cranioplasty and its relation to various parameters (imaging, demographics, time of cranioplasty, and type of graft) as well as its possible relation to postsurgical complications. The authors performed a prospective study in which they selected as participants adults who had undergone unilateral frontotemporoparietal DC and were planned to have cranioplasty. Intracranial pressure was measured with optical fiber sensor in the epidural space and did not affect cranioplasty in any way.Twenty-five patients met the criteria. The mean vcICP (value change of ICP) was 1.2 mm Hg, the mean ΔICP (absolute value change of the ICP) was 2.24 mm Hg and in the majority of cases there was an increase in ICP. The authors found 3 statistically significant correlations: between gender and ΔICP, Δtime (time between DC and CP) and vcICP, and pre-ICP and ±ICP (quantitative change of the ICP).Μale patients tend to develop larger changes of ICP values during CP. As the time between the 2 procedures (DC and CP) gets longer, the vcICP is decreased. However, after certain time it shows a tendency to remain around zero. Lower pre-ICP values (close to or below zero) are more possible to increase after bone flap placement. It seems that the brain tends to restore its pre-DC conditions after CP by taking near-to-normal ICP values.

Patient Outcomes at Twelve Months after Early Decompressive Craniectomy for Diffuse Traumatic Brain Injury in the Randomized DECRA Clinical Trial

Functional outcomes at 12 months were a secondary outcome of the randomized DECRA trial of early decompressive craniectomy for severe diffuse traumatic brain injury (TBI) and refractory intracranial hypertension.

In the DECRA trial, patients were randomly allocated 1:1 to either early decompressive craniectomy or intensive medical therapies (standard care). We conducted planned secondary analyses of the DECRA trial outcomes at 6 and 12 months, including all 155 patients.

We measured functional outcome using the Glasgow Outcome Scale-Extended (GOS-E). We used ordered logistic regression, and dichotomized the GOS-E using logistic regression, to assess outcomes in patients overall and in survivors. We adjusted analyses for injury severity using the International Mission for Prognosis and Analysis of Clinical Trials in TBI (IMPACT) model.

At 12 months, the odds ratio (OR) for worse functional outcomes in the craniectomy group (OR 1.68; 95% confidence interval [CI]: 0.96-2.93; p = 0.07) was no longer significant. Unfavorable functional outcomes after craniectomy were 11% higher (59% compared with 48%), but were not significantly different from standard care (OR 1.58; 95% CI: 0.84-2.99; p = 0.16). Among survivors after craniectomy, there were fewer good (OR 0.33; 95% CI: 0.12-0.91; p = 0.03) and more vegetative (OR 5.12; 95% CI: 1.04-25.2; p = 0.04) outcomes.

Similar outcomes in survivors were found at 6 months after injury. Vegetative (OR 5.85; 95% CI: 1.21-28.30; p = 0.03) and severely disabled outcomes (OR 2.49; 95% CI: 1.21-5.11; p = 0.01) were increased.

Twelve months after severe diffuse TBI and early refractory intracranial hypertension, decompressive craniectomy did not improve outcomes and increased vegetative survivors.

From head micro-motions towards CSF dynamics and non-invasive intracranial pressure monitoring

Continuous monitoring of the intracranial pressure (ICP) is essential in neurocritical care. There are a variety of ICP monitoring systems currently available, with the intraventricular fluid filled catheter transducer currently representing the “gold standard”. As the placement of catheters is associated with the attendant risk of infection, hematoma formation, and seizures, there is a need for a reliable, non-invasive alternative. In the present study we suggest a unique theoretical framework based on differential geometry invariants of cranial micro-motions with the potential for continuous non-invasive ICP monitoring in conservative traumatic brain injury (TBI) treatment. As a proof of this concept, we have developed a pillow with embedded mechanical sensors and collected an extensive dataset (> 550 h on 24 TBI coma patients) of cranial micro-motions and the reference intraparenchymal ICP. From the multidimensional pulsatile curve we calculated the first Cartan curvature and constructed a ”fingerprint” image (Cartan map) associated with the cerebrospinal fluid (CSF) dynamics. The Cartan map features maxima bands corresponding to a pressure wave reflection corresponding to a detectable skull tremble. We give evidence for a statistically significant and patient-independent correlation between skull micro-motions and ICP time derivative. Our unique differential geometry-based method yields a broader and global perspective on intracranial CSF dynamics compared to rather local catheter-based measurement and has the potential for wider applications.

Cardiac-gated intracranial elastance in a swine model of raised intracranial pressure: a novel method to assess intracranial pressure-volume dynamics

OBJECTIVE

Previous studies have demonstrated the importance of intracranial elastance; however, methodological difficulties have limited widespread clinical use. Measuring elastance may offer potential benefit in helping to identify patients at risk for untoward intracranial pressure (ICP) elevation from small rises in intracranial volume. The authors sought to develop an easily used method that accounts for the changing ICP that occurs over a cardiac cycle and to assess this method in a large-animal model over a broad range of ICPs.

METHODS

The authors used their previously described cardiac-gated intracranial balloon pump and swine model of cerebral edema. In the present experiment they measured elastance at 4 points along the cardiac cycle-early systole, peak systole, mid-diastole, and end diastole-by using rapid balloon inflation to 1 ml over an ICP range of 10-30 mm Hg.

RESULTS

The authors studied 7 swine with increasing cerebral edema. Intracranial elastance rose progressively with increasing ICP. Peak-systolic and end-diastolic elastance demonstrated the most consistent rise in elastance as ICP increased. Cardiac-gated elastance measurements had markedly lower variance within swine compared with non-cardiac-gated measures. The slope of the ICP-elastance curve differed between swine. At ICP between 20 and 25 mm Hg, elastance varied between 8.7 and 15.8 mm Hg/ml, indicating that ICP alone cannot accurately predict intracranial elastance.

CONCLUSIONS

Measuring intracranial elastance in a cardiac-gated manner is feasible and may offer an improved precision of measure. The authors' preliminary data suggest that because elastance values may vary at similar ICP levels, ICP alone may not necessarily best reflect the state of intracranial volume reserve capacity. Paired ICP-elastance measurements may offer benefit as an adjunct "early warning monitor" alerting to the risk of untoward ICP elevation in brain-injured patients that is induced by small increases in intracranial volume.

Analysis of Normal High-Frequency Intracranial Pressure Values and Treatment Threshold in Neurocritical Care Patients: Insights into Normal Values and a Potential Treatment Threshold

Importance

Intracranial pressure (ICP) elevation is a compartment syndrome that impairs blood flow to the brain. Despite the importance of ICP values in neurocritical care, normal ICP values and the precise ICP threshold at which treatment should be initiated remain uncertain.

Objective

To refine our understanding of normal ICP values and determine the ICP threshold most strongly associated with outcome.

Design, Setting, and Participants

Prospective observational study (2004-2010), with outcomes determined at hospital discharge. The study included neurocritical care patients from a single level I trauma center, San Francisco General Hospital. Three hundred eighty-three patients had a traumatic brain injury with or without craniectomy; 140 patients had another indication for ICP monitoring. Consecutive patients were studied. Data analyses were completed between March 2015 and December 2019.

Exposures

Five hundred twenty-three ICP-monitored patients.

Main Outcomes and Measures

A computer system prospectively and automatically collected 1-minute physiologic data from patients in the intensive care unit during a 6-year period. Mean ICP was calculated, as was the proportion of ICP values greater than thresholds from 1 to 80 mm Hg in 1-mm Hg increments. The association between these measures and outcome was explored for various epochs up to 30 days from the time of injury. A principal component analysis was used to explore physiologic changes at various ICP thresholds, and elastic net regression was used to identify ICP thresholds most strongly associated with Glasgow Outcome Scale score at discharge.

Results

Of the 523 studied patients, 70.7% of studied patients were men (n = 370) and 72.1% had a traumatic brain injury (n = 377). A total of 4 090 964 1-minute ICP measurements were recorded for the included patients (7.78 years of recordings). Intracranial pressure values of 8 to 9 mm Hg were most commonly recorded and could possibly reflect normal values. The principal component analysis suggested state shifts in the physiome occurred at ICPs greater than 19 mm Hg and 24 mm Hg. Elastic net regression identified an ICP threshold of 19 mm Hg as most robustly associated with outcome when considering all neurocritical care patients, patients with TBI, and patients with TBI who underwent craniectomy. Intracranial pressure values greater than 19 mm Hg were associated with mortality, while lower values were associated with outcome in surviving patients.

Conclusions and Relevance

This study provides insight into what normal ICP values could be. An ICP threshold of 19 mm Hg was robustly associated with outcome in studied patients, although lower ICP values were associated with outcome in surviving patients.

Neuroinfectious Disease Emergencies

Neuroinfectious diseases can affect immunocompetent and immunosuppressed individuals and cause a variety of emergencies including meningitis, encephalitis, and abscess. Neurologic infections are frequently complicated by secondary injuries that also present emergently such as cerebrovascular disease, acute obstructive hydrocephalus, and seizure. In most cases, timely recognition and early treatment of infection can improve the morbidity and mortality of infectious neurologic emergencies.

Impact of Intracranial Pressure Monitor-Guided Therapy on Neurologic Outcome After Spontaneous Nontraumatic Intracranial Hemorrhage

OBJECTIVES

Intracranial pressure (ICP) monitors have been used in some patients with spontaneous intracranial hemorrhage (ICH) to provide information to guide treatment without clear evidence for its use in this population. We assessed the impact of ICP monitor placement, including external ventricular drains and intraparenchymal monitors, on neurologic outcome in this population.

MATERIALS AND METHODS

In this secondary analysis of the Minimally Invasive Surgery Plus Alteplase for Intracerebral Hemorrhage Evacuation III trial, the primary outcome was poor outcome (modified Rankin Scale score 4-6) and the secondary outcome was death, at 1 year from onset. We compared outcomes in patients with or without an ICP monitor using unadjusted and adjusted logistic regression models. The analyses were repeated in a balanced cohort created with propensity score matching.

RESULTS

Seventy patients underwent ICP monitor placement and 424 did not. Poor outcome was seen in 77.1% of patients in the ICP-monitor subgroup compared with 53.8% in the no-monitor subgroup (p<0.001). Of patients in the ICP-monitor subgroup, 31.4% died, compared with 21.0% in the no-monitor subgroup (p=0.053). In multivariate models, ICP monitor placement was associated with a >2-fold greater risk of poor outcome (odds ratio 2.76, 95% CI 1.30-5.85, p=0.008), but not with death (p=0.652). Our findings remained consistent in the propensity score-matched cohort.

CONCLUSION

These results question whether ICP monitor-guided therapy in patients with spontaneous nontraumatic ICH improves outcome. Further work is required to define the causal pathway and improve identification of patients that might benefit from invasive ICP monitoring.

Neurovascular physiology and neurocritical care

The neurological intensive care unit plays an integral role in the management of cerebrovascular disease in the acute and perioperative period. Understanding the use of intracranial pressure (ICP) monitoring and how to apply the appropriate intervention for ICP elevation to ensure adequate cerebral perfusion is the foundation of neurocritical care. Careful management of the interplay between cerebral and systemic physiology, particularly in disorders of cerebral autoregulation, is critical in preventing secondary brain injury. Finally, understanding the cerebral pathophysiology of the underlying injured brain in acute stroke, subarachnoid hemorrhage, and arterial stenosis can help to guide the optimal use of interventional endovascular procedures in these disease states.

Clinical Significance of Decompressive Craniectomy Surface Area and Side

Objective

Decompressive craniectomy (DC) can partially remove the unyielding skull vault and make affordable space for the expansion of swelling brain contents. The objective of this study was to compare clinical outcome according to DC surface area (DC area) and side.

Methods

A total of 324 patients underwent different surgical methods (unilateral DC, 212 cases and bilateral DC, 112 cases) were included in this retrospective analysis. Their mean age was 53.4±16.6 years (median, 54 years). Neurological outcome (Glasgow outcome scale), ventricular intracranial pressure (ICP), and midline shift change (preoperative minus postoperative) were compared according to surgical methods and total DC area, DC surface removal rate (DC%) and side.

Results

DC surgery was effective for ICP decrease (32.3±16.7 mmHg vs. 19.2±13.4 mmHg, p<0.001) and midline shift change (12.5±7.6 mm vs. 7.8±6.9 mm, p<0.001). The bilateral DC group showed larger total DC area (125.1±27.8 cm² for unilateral vs. 198.2±43.0 cm² for bilateral, p<0.001). Clinical outcomes were nonsignificant according to surgical side (favorable outcome, p=0.173 and mortality, p=0.470), significantly better when total DC area was over 160 cm² and DC% was 46% (p=0.020 and p=0.037, respectively).

Conclusion

DC surgery is effective in decrease the elevated ICP, decrease the midline shift and improve the clinical outcome in massive brain swelling patient. Total DC area and removal rate was larger in bilateral DC than unilateral DC but clinical outcome was not influenced by DC side. DC area more than 160 cm² and DC surface removal rate more than 46% were more important than DC side.

Role of Intraoperative ICP And CPP Measurement for Predicting Surgical Outcome in Severe Traumatic Brain Injury

Introduction Traumatic brain injury (TBI) is one of the leading causes of mortality and disability worldwide, and optimizing the management of these patients is a continuing challenge. Intraoperative intracranial pressure (ICP) and cerebral perfusion pressure (CPP) were evaluated for use as prognostic indicators after surgery for severe TBI. Although ICP and CPP monitoring is standard postsurgery treatment for TBI, very few studies have reported the use of ICP and CPP values monitored during surgery.

Objectives The objectives of this study were to evaluate the use of intraoperative ICP and CPP values as prognostic indicators and as subjective guidelines for managing severe TBI.

Materials and Methods All patients with severe TBI who underwent surgical decompression and ICP monitoring intraoperatively were included in our study from 2017 to 2018. We measured ICP and CPP values after creation of the first burr hole, after hematoma evacuation, and after wound closure.

Results From the analysis of receiver-operated characteristic (ROC) curves, we observed that ICP initial (cutoff > 28 mm Hg) and CPP initial (cutoff < 44.5 mm Hg) are the best predictors of unfavorable outcomes. Favorable outcome (Glasgow outcome scale [GOS] 4 and 5) and unfavorable outcome (GOS 1–3) after 6 months were achieved in 64.1 and 35.8% of patients, respectively. There was significant difference between the ICP and CPP values which are measured after the first burrhole, after hematoma evacuation, and after scalp closure in both favorable and unfavorable outcomes. The highest positive Pearson’s correlation coefficient is found between GOS and ICP and CPP after first burr hole.

Conclusion Monitoring ICP and CPP during surgery improves management in patients with severe TBI and provides an early prognostic indicator in such patients.

Quantification of Capillary Perfusion in an Animal Model of Acute Intracranial Hypertension

Intracranial hypertension (IH) is a common feature of many pathologies, including brain edema. In the brain, the extended network of capillaries ensures blood flow to meet local metabolic demands. Capillary circulation may be severely affected by IH, but no studies have quantified the effect of intracranial pressure (ICP) and cerebral perfusion pressure (CPP) on capillary perfusion during the development of brain edema. We used optical coherence tomography angiography to quantify relative changes of fractional perfused volume (FPV) in cortical capillaries and simultaneously monitored ICP and blood pressure (BP) in anesthetized male C57Bl/6NTac mice during development of brain edema induced by water intoxication (WI) within 30 min. WI induced severe IH and brain herniation. ICP and CPP reached 90.2 mm Hg and 38.4 mm Hg, respectively. FPV was significantly affected already at normal ICP (ICP <15 mm Hg, slope ≈ -1.46, p < 0.001) and, at the onset of IH (ICP = 20-22 mm Hg), FPV was 17.9 ± 13.3% lower than baseline. A decreasing trend was observed until the ICP peak (Δ%FPV = -43.6 ± 19.2%). In the ICP range of 7-42 mm Hg, relative changes in FPV were significantly correlated with ICP, BP, and CPP (p < 0.001), with ICP and CPP being the best predictors. In conclusion, elevated ICP induces a gradual collapse of the cerebral microvasculature, which is initiated before the clinical threshold of IH. In summary, the estimate of capillary perfusion might be essential in patients with IH to assess the state of the brain microcirculation and to improve the availability of oxygen and nutrients to the brain.

[Clinical and MRI predictors of coma duration, intensive care and outcome of traumatic brain injury]

OBJECTIVE

This research is aimed to study the clinical and MRI predictors of coma duration, the intensity of critical care, and outcome of traumatic brain injury (TBI).

MATERIAL AND METHODS

The data from 309 patients with TBI of varying severity were included in the analysis, of whom 257 (86.7%) were treated in the intensive care unit (ICU), including 196 (63.4%) patients admitted in a comatose state lasting longer than 1 day. All patients underwent brain MRI within 21 days after the injury. MRI findings were classified according to MRI grading scale of brain damage level and localization proposed previously.

RESULTS

The proposed MRI grading significantly correlated with the Glasgow coma (GCS, r=-0.67; p<0.0001) and Glasgow outcome (0.69; p<0.001) scores in the entire group. In a subgroup of comatose patients (GCS<9) it correlated with coma duration (r=0.52; p<0.0001). Spearman correlation analysis showed a significant relationship between the MRI classification and a number of parameters: ICU length of stay (r=0.62; p<0.0001), the duration of artificial ventilation (r=0.47; p<0.0001), the rate of artificial ventilation, sedatives, analgesics, mannitol, hypertonic saline and vasopressors usage (p<0.01). These data confirm the relationship between higher grades of MRI classification (deep brain damage) and the need for the escalation of intensive care main components.

CONCLUSION

Our results support the hypothesis that the levels and localization of brain damage, estimated by the proposed MRI grading scale, might be predictors of coma duration, intensity and duration of intensive care, and TBI outcomes. A prognosis based on clinical and neuroimaging data comparison can be valuable for planning and efficient use of the hospital beds and ICU resources, for optimizing the patient flow and timing of patient transfer to neurorehabilitation facilities.

Optic nerve sheath diameter change in prediction of malignant cerebral edema in ischemic stroke: an observational study

Background

In acute large anterior circulation infarct patients with large core volume, we evaluated the role of optic nerve sheath diameter (ONSD) change rates in prediction of malignant progression.

Methods

We performed a retrospective observational study including patients with anterior circulation acute ischemic stroke with large ischemic cores from January 2010 to October 2017. Primary outcome was defined as undergoing decompressive surgery or death due to severe cerebral edema, and termed malignant progression. Patients were divided into malignant progressors and nonprogressors. Malignant progression was divided into early progression that occurred before D1 CT, and late progression that occurred afterwards. Retrospective analysis of changes in mean ONSD/eyeball transverse diameter (ETD) ratio, and midline shifting (MLS) were evaluated on serial computed tomography (CT). Through analysis of CT at baseline, postprocedure, and at D1, the predictive ability of time based change in ONSD/ETD ratio in predicting malignant progression was evaluated.

Results

A total of 58 patients were included. Nineteen (32.8%) were classified as malignant; 12 early, and 7 late progressions. In analysis of CT_{postprocedure}, A 1 mm/hr. rate of change in MLS during the CT_baseline-CT_{postprocedure} time phase lead to a 6.7 fold increased odds of early malignant progression (p < 0.05). For ONSD/ETD, 1%/hr. change lead to a 1.6 fold increased odds, but this association was trending (p = 0.249). In the CT_D1, 1%/day change of ONSD/ETD in the CT_baseline-CT_D1 time phase lead to a 1.4 fold increased odds of late malignant progression (p = 0.021) while 1 mm/day rate of change in MLS lead to a 1.5 fold increased odds (p = 0.014).

Conclusions

The rate of ONSD/ETD changes compared to baseline at D1 CT can be a predictor of late malignant progression along with MLS. ONSD/ETD change rates evaluated at postprocedure did not predict early malignant progression.

Does the skull Hounsfield unit predict shunt dependent hydrocephalus after decompressive craniectomy for traumatic acute subdural hematoma?

Background and purpose

Posttraumatic hydrocephalus affects 11.9%–36% of patients undergoing decompressive craniectomy (DC) after traumatic brain injury and necessitates a ventriculo-peritoneal shunt placement. As bone and arachnoid trabeculae share the same collagen type, we investigated possible connections between the skull Hounsfield unit (HU) values and shunt-dependent hydrocephalus (SDHC) in patients that received cranioplasty after DC for traumatic acute subdural hematoma (SDH).

Methods

We measured HU values in the frontal bone and internal occipital protuberance from admission brain CT. Receiver operating characteristic curve analysis was performed to identify the optimal cut-off skull HU values for predicting SDHC in patients receiving cranioplasty after DC due to traumatic acute SDH. We investigated independent predictive factors for SDHC occurrence using multivariable logistic regression analysis.

Results

A total of 162 patients (>15 years of age) were enrolled in the study over an 11-year period from two university hospitals. Multivariable logistic analysis revealed that the group with simultaneous frontal skull HU ≤797.4 and internal occipital protuberance HU ≤586.5 (odds ratio, 8.57; 95% CI, 3.05 to 24.10; P<0.001) was the only independent predictive factor for SDHC in patients who received cranioplasty after DC for traumatic acute SDH.

Conclusions

Our study reveals a potential relationship between possible low bone mineral density and development of SDHC in traumatic acute SDH patients who had undergone DC. Our findings provide deeper insight into the association between low bone mineral density and hydrocephalus after DC for traumatic acute SDH.

Hypertonic saline versus other intracranial pressure-lowering agents for people with acute traumatic brain injury

BACKGROUND

Increased intracranial pressure has been shown to be strongly associated with poor neurological outcomes and mortality for patients with acute traumatic brain injury. Currently, most efforts to treat these injuries focus on controlling the intracranial pressure. Hypertonic saline is a hyperosmolar therapy that is used in traumatic brain injury to reduce intracranial pressure. The effectiveness of hypertonic saline compared with other intracranial pressure-lowering agents in the management of acute traumatic brain injury is still debated, both in the short and the long term.

OBJECTIVES

To assess the comparative efficacy and safety of hypertonic saline versus other intracranial pressure-lowering agents in the management of acute traumatic brain injury.

SEARCH METHODS

We searched Cochrane Injuries' Specialised Register, CENTRAL, PubMed, Embase Classic+Embase, ISI Web of Science: Science Citation Index and Conference Proceedings Citation Index-Science, as well as trials registers, on 11 December 2019. We supplemented these searches with searches of four major Chinese databases on 19 September 2018. We also checked bibliographies, and contacted trial authors to identify additional trials.

SELECTION CRITERIA

We sought to identify all randomised controlled trials (RCTs) of hypertonic saline versus other intracranial pressure-lowering agents for people with acute traumatic brain injury of any severity. We excluded cross-over trials as incompatible with assessing long-term outcomes.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened search results to identify potentially eligible trials and extracted data using a standard data extraction form. Outcome measures included: mortality at end of follow-up (all-cause); death or disability (as measured by the Glasgow Outcome Scale (GOS)); uncontrolled intracranial pressure (defined as failure to decrease the intracranial pressure to target and/or requiring additional intervention); and adverse events e.g. rebound phenomena; pulmonary oedema; acute renal failure during treatment).

MAIN RESULTS

Six trials, involving data from 287 people, met the inclusion criteria. The majority of participants (91%) had a diagnosis of severe traumatic brain injury. We had concerns about particular domains of risk of bias in each trial, as physicians were not reliably blinded to allocation, two trials contained participants with conditions other than traumatic brain injury and in one trial, we had concerns about missing data for important outcomes. The original protocol was available for only one trial and other trials (where registered) were registered retrospectively. Meta-analysis for both the primary outcome (mortality at final follow-up) and for 'poor outcome' as per conventionally dichotomised GOS criteria, was only possible for two trials. Synthesis of long-term outcomes was inhibited by the fact that two trials ceased data collection within two hours of a single bolus dose of an intracranial pressure-lowering agent and one at discharge from the intensive care unit (ICU). Only three trials collected data after participants were released from hospital, one of which did not report mortality and reported a 'poor outcome' by GOS criteria in an unconventional way. Substantial missing data in a key trial meant that in meta-analysis we report 'best-case' and 'worst-case' estimates alongside available case analysis. In no scenario did we discern a clear difference between treatments for either mortality or poor neurological outcome. Due to variation in modes of drug administration (including whether it followed or did not follow cerebrospinal fluid (CSF) drainage, as well as different follow-up times and ways of reporting changes in intracranial pressure, as well as no uniform definition of 'uncontrolled intracranial pressure', we did not perform meta-analysis for this outcome and report results narratively, by individual trial. Trials tended to report both treatments to be effective in reducing elevated intracranial pressure but that hypertonic saline had increased benefits, usually adding that pretreatment factors need to be considered (e.g. serum sodium and both system and brain haemodynamics). No trial provided data for our other outcomes of interest. We consider evidence quality for all outcomes to be very low, as assessed by GRADE; we downgraded all conclusions due to imprecision (small sample size), indirectness (due to choice of measurement and/or selection of participants without traumatic brain injury), and in some cases, risk of bias and inconsistency. Only one of the included trials reported data on adverse effects; a rebound phenomenon, which was present only in the comparator group (mannitol). None of the trials reported data on pulmonary oedema or acute renal failure during treatment. On the whole, trial authors do not seem to have rigorously sought to collect data on adverse events.

AUTHORS' CONCLUSIONS

This review set out to find trials comparing hypertonic saline to a potential range of other intracranial pressure-lowering agents, but only identified trials comparing it with mannitol or mannitol in combination with glycerol. Based on limited data, there is weak evidence to suggest that hypertonic saline is no better than mannitol in efficacy and safety in the long-term management of acute traumatic brain injury. Future research should be comprised of large, multi-site trials, prospectively registered, reported in accordance with current best practice. Trials should investigate issues such as the type of traumatic brain injury suffered by participants and concentration of infusion and length of time over which the infusion is given.

Hypertonic saline versus other intracranial pressure-lowering agents for people with acute traumatic brain injury

BACKGROUND

Increased intracranial pressure (ICP) has been shown to be strongly associated with poor neurological outcomes and mortality for patients with acute traumatic brain injury (TBI). Currently, most efforts to treat these injuries focus on controlling the ICP. Hypertonic saline (HTS) is a hyperosmolar therapy that is used in traumatic brain injury to reduce intracranial pressure. The effectiveness of HTS compared with other ICP-lowering agents in the management of acute TBI is still debated, both in the short and the long term.

OBJECTIVES

To assess the comparative efficacy and safety of hypertonic saline versus other ICP-lowering agents in the management of acute TBI.

SEARCH METHODS

We searched the Cochrane Injuries Group's Specialised Register, The Cochrane Library, PubMed, Embase Classic+Embase (OvidSP), ISI Web of Science: Science Citation Index and Conference Proceedings Citation Index-Science, as well as trials registers, on 11 December 2019. We supplemented these searches using four major Chinese databases on 19 September 2018. We also checked bibliographies, and contacted study authors to identify additional studies.

SELECTION CRITERIA

We sought to identify all randomised controlled trials (RCTs) of HTS versus other intracranial pressure-lowering agents for people with acute TBI of any severity. We excluded cross-over trials as incompatible with assessing long term outcomes.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened search results to identify potentially eligible trials and extracted data using a standard data extraction form. Outcome measures included: mortality at end of follow-up (all-cause); death or disability (as measured by the Glasgow Outcome Scale (GOS)); uncontrolled ICP (defined as failure to decrease the ICP to target and/or requiring additional intervention); and adverse events (AEs) (e.g. rebound phenomena; pulmonary oedema; acute renal failure during treatment).

MAIN RESULTS

Six trials, involving data from 295 people, met the inclusion criteria. The majority of participants (89%) had a diagnosis of severe TBI. We had concerns about particular domains of risk of bias in each trial, as physicians were not reliably blinded to allocation, two trials contained participants with conditions other than TBI and in one trial, there were concerns about missing data for important outcomes. The original protocol was available for only one study and other trials (where registered) were registered retrospectively. Meta-analysis for both the primary outcome (mortality at final follow up) and for 'poor outcome' as per conventionally dichotomised GOS criteria, was only possible for two studies. Synthesis of long-term outcomes was inhibited by the fact that two ceased data collection within two hours of a single bolus dose of an ICP-lowering agent and one at discharge from ICU. Only three studies collected data after release from hospital. Due to variation in modes of drug administration, follow-up times, and ways of reporting changes in ICP, as well as no uniform definition of 'uncontrolled ICP', we did not perform meta-analysis for this outcome and report results narratively, by individual trial. Trials tended to report both treatments to be effective in reducing elevated ICP but that HTS had increased benefits, usually adding that pretreatment factors need to be considered (e.g. serum sodium and both system and brain hemodynamics). No trial provided data for our other outcomes of interest. Evidence for all outcomes is considered very low, as assessed by GRADE. All conclusions were downgraded due to imprecision (small sample size), indirectness (due to choice of measurement and/or selection of patients without TBI), and in some cases, risk of bias and inconsistency. Only one of the included trials reported data on adverse effects (AEs) - a rebound phenomenon, which was present only in the comparator group (mannitol). No data were reported on pulmonary oedema or acute renal failure during treatment. On the whole, investigators do not seem to have rigorously sought to collect data on AEs.

AUTHORS' CONCLUSIONS

This review set out to find trials comparing HTS to a potential range of other ICP-lowering agents, but only identified trials comparing it with mannitol or mannitol in combination with glycerol. Based on limited data, there is weak evidence to suggest that HTS is no better than mannitol in efficacy and safety in the long-term management of acute TBI. Future research should be comprised of large, multi-site trials, prospectively registered, reported in accordance with current best practice. Issues such as the type of TBI suffered by participants and concentration of infusion and length of time over which the infusion is given should be investigated.

Indomethacin for intracranial hypertension secondary to severe traumatic brain injury in adults

BACKGROUND

Among people who have suffered a traumatic brain injury, increased intracranial pressure continues to be a major cause of early death; it is estimated that about 11 people per 100 with traumatic brain injury die. Indomethacin (also known as indometacin) is a powerful cerebral vasoconstrictor that can reduce intracranial pressure and, ultimately, restore cerebral perfusion and oxygenation. Thus, indomethacin may improve the recovery of a person with traumatic brain injury.

OBJECTIVES

To assess the effects of indomethacin for adults with severe traumatic brain injury.

SEARCH METHODS

We ran the searches from inception to 23 August 2019. We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2019, Issue 8) in the Cochrane Library, Ovid MEDLINE, Ovid Embase, CINAHL Plus (EBSCO), four other databases, and clinical trials registries. We also screened reference lists and conference abstracts, and contacted experts in the field.

SELECTION CRITERIA

Our search criteria included randomised controlled trials (RCTs) that compared indomethacin with any control in adults presenting with severe traumatic brain injury associated with elevated intracranial pressure, with no previous decompressive surgery.

DATA COLLECTION AND ANALYSIS

Two review authors independently decided on the selection of the studies. We followed standard Cochrane methods.

MAIN RESULTS

We identified no eligible studies for this review, either completed or ongoing.

AUTHORS' CONCLUSIONS

We found no studies, either completed or ongoing, that assessed the effects of indomethacin in controlling intracranial hypertension secondary to severe traumatic brain injury. Thus, we cannot draw any conclusions about the effects of indomethacin on intracranial pressure, mortality rates, quality of life, disability or adverse effects. This absence of evidence should not be interpreted as evidence of no effect for indomethacin in controlling intracranial hypertension secondary to severe traumatic brain injury. It means that we have not identified eligible research for this review.

Impact of Increased Intracranial Pressure on Pupillometry: A Replication Study

In a diverse, multicenter population, to confirm or refute the conclusions that pupillary light reflex changes are associated with increased intracranial pressure.

Comparison of electrical impedance tomography and intracranial pressure during dehydration treatment of cerebral edema

Cerebral edema after brain injury can lead to brain damage and death if diagnosis and treatment are delayed. This study investigates the feasibility of employing electrical impedance tomography (EIT) as a non-invasive imaging tool for monitoring the development of cerebral edema, in which impedance imaging of the brain related to brain water content is compared with intracranial pressure (ICP). We enrolled forty patients with cerebral hemorrhage who underwent lateral external ventricular drain with intraventricular ICP and EIT monitoring for 3 h after initiation of dehydration treatment. The average reconstructed impedance value (ARV) calculated from EIT images was compared with ICP. Dehydration effects induced changes in ARV and ICP showed a close negative correlation in all patients, and the mean correlation reached R2 = 0.78 ± 0.16 (p < .001). A regression equation (R2 = 0.62, p < .001) was formulated from the total of measurement data. The 95% limits of agreement were - 6.13 to 6.13 mmHg. Adaptive clustering and variance analysis of normalized changes in ARV and ICP showed 92.5% similarity and no statistically significant differences (p > .05). Moreover, the sensitivity, specificity and area under the curve of changes in ICP >10 mmHg were 0.65, 0.73 and 0.70 respectively. The findings show that EIT can monitor changes in brain water content associated with cerebral edema, which could provide a real-time and non-invasive imaging tool for early identification of cerebral edema and the evaluation of mannitol dehydration.

Respect your elders: effects of ageing on intracranial pressure monitor use in traumatic brain injury

BACKGROUND

The Brain Trauma Foundation recommends intracranial pressure (ICP) monitor placement for patients with severe traumatic brain injury (TBI). Adherence with these guidelines in elderly patients is unknown. We hypothesized that disparities in ICP monitor placement would exist based on patient age.

METHODS

Using the National Trauma Data Bank (2010-2014), we identified patients admitted for blunt TBI with admission Glasgow Coma Scale (GCS) scores of 3-8. Patients were excluded if they had a non-Head Abbreviated Injury Scale (AIS) score ≥3, hospital length of stay <24 hours or were discharged from the emergency department. Demographic data, ICP monitor placement, GCS, AIS-Head, Injury Severity Score, and outcome measures were collected. Propensity score matching between ICP monitor and non-ICP monitor patients was used for logistic regression and Cox multivariate regression analyses.

RESULTS

Of the 30 710 patients with blunt TBI with GCS scores of 3-8 included in our study, 4093 were treated with an ICP monitor. ICP monitor placement rates significantly decreased with increasing age. Multivariable analysis demonstrated that patients treated with an ICP monitor were more likely to be younger, male, have private/commercial insurance, and receive care at an institution with three or more neurosurgeons.

CONCLUSION

Patients ≥65 years of age with severe blunt TBI are less likely to be treated with an ICP monitor than younger patients. Age disparities in adherence to Brain Trauma Foundation guidelines may alter the outcomes for patients with severe TBI.

LEVEL OF EVIDENCE

Level IV.

Continuous Assessment of "Optimal" Cerebral Perfusion Pressure in Traumatic Brain Injury: A Cohort Study of Feasibility, Reliability, and Relation to Outcome

BACKGROUND

Guidelines recommend maintaining cerebral perfusion pressure (CPP) between 60 and 70 mmHg in patients with severe traumatic brain injury (TBI), but acknowledge that optimal CPP may vary depending on cerebral blood flow autoregulation. Previous retrospective studies suggest that targeting CPP where the pressure reactivity index (PRx) is optimized (CPP_opt) may be associated with improved recovery.

METHODS

We performed a retrospective cohort study involving TBI patients who underwent PRx monitoring to assess issues of feasibility relevant to future interventional studies: (1) the proportion of time that CPP_opt could be detected; (2) inter-observer variability in CPP_opt determination; and (3) agreement between manual and automated CPP_opt estimates. CPP_opt was determined for consecutive 6-h epochs during the first week following TBI. Sixty PRx-CPP tracings were randomly selected and independently reviewed by six critical care professionals. We also assessed whether greater deviation between actual CPP and CPP_opt (ΔCPP) was associated with poor outcomes using multivariable models.

RESULTS

In 71 patients, CPP_opt could be manually determined in 985 of 1173 (84%) epochs. Inter-observer agreement for detectability was moderate (kappa 0.46, 0.23-0.68). In cases where there was consensus that it could be determined, agreement for the specific CPP_opt value was excellent (weighted kappa 0.96, 0.91-1.00). Automated CPP_opt was within 5 mmHg of manually determined CPP_opt in 93% of epochs. Lower PRx was predictive of better recovery, but there was no association between ΔCPP and outcome. Percentage time spent below CPP_opt increased over time among patients with poor outcomes (p = 0.03). This effect was magnified in patients with impaired autoregulation (defined as PRx > 0.2; p = 0.003).

CONCLUSION

Prospective interventional clinical trials with regular determination of CPP_opt and corresponding adjustment of CPP goals are feasible, but measures to maximize consistency in CPP_opt determination are necessary. Although we could not confirm a clear association between ΔCPP and outcome, time spent below CPP_opt may be particularly harmful, especially when autoregulation is impaired.

[Intracranial pressure monitoring in polytrauma patients with traumatic brain injury]

BACKGROUND

The monitoring of intracranial pressure (ICP) represents a cornerstone in the intensive care of patients with traumatic brain injury (TBI) and the industry provides various technical solutions to this end. Decompressive craniectomy can be an option if conservative measures fail to reduce excessive ICP.

OBJECTIVE

To examine the pathophysiology of ICP in trauma, the management of polytrauma involving TBI, and the indications for decompressive craniectomy; and to compare the different monitoring systems and their complications.

MATERIAL AND METHODS

A retrospective analysis of TBI patients between 2010 and 2016 was performed. Relevant publications are discussed, particularly those relating to the indications for monitoring and its influence on polytrauma management.

RESULTS

Between 2010 and 2016, 106 patients with closed TBI and a mean age of 65.9 years received a total of 120 ICP monitors, most of which were parenchyma devices (111/120), followed by intraventricular catheters (8/120), and one combined system (1/120). Of these patients, 27.4% had sustained polytrauma, whilst 33% regularly used anticoagulants. ICP monitors were removed after 8.5 days on an average and the mean ICU stay was 20 days. Probe insertion was combined with craniectomy in 69.8% patients. Probe-related complications, most commonly involving malfunction, were seen in 6.6%. The duration of monitoring was significantly related to polytrauma (p ≤ 0.001) and age <60 (p = 0.03). ICU stay was also significantly related to polytrauma (p = 0.02) and monitoring complications (p ≤ 0.001). Mortality was related to anticoagulant medication (p = 0.01) and age <60 (p = 0.03).

CONCLUSIONS

ICP monitoring is one of the most important tools in TBI treatment. The course and outcome of these severe injuries is affected by polytrauma, age, and the use of anticoagulants.

Consideration of the Intracranial Pressure Threshold Value for the Initiation of Traumatic Brain Injury Treatment: A Xenon CT and Perfusion CT Study

BACKGROUND

Monitoring of intracranial pressure (ICP) is considered to be fundamental for the care of patients with severe traumatic brain injury (TBI) and is routinely used to direct medical and surgical therapy. Accordingly, some guidelines for the management of severe TBI recommend that treatment be initiated for ICP values >20 mmHg. However, it remained to be accounted whether there is a scientific basis to this instruction. The purpose of the present study was to clarify whether the basis of ICP values >20 mmHg is appropriate.

SUBJECT AND METHODS

We retrospectively reviewed 25 patients with severe TBI who underwent neuroimaging during ICP monitoring within the first 7 days. We measured cerebral blood flow (CBF), mean transit time (MTT), cerebral blood volume (CBV), and ICP 71 times within the first 7 days.

RESULTS

Although the CBF, MTT, and CBV values were not correlated with the ICP value at ICP values ≤20 mmHg, the CBF value was significantly negatively correlated with the ICP value (r = -0.381, P < 0.05) at ICP values >20 mmHg. The MTT value was also significantly positively correlated with the ICP value (r = 0.638, P < 0.05) at ICP values >20 mmHg.

CONCLUSION

The cerebral circulation disturbance increased with the ICP value. We demonstrated the cerebral circulation disturbance at ICP values >20 mmHg. This study suggests that an ICP >20 mmHg is the threshold to initiate treatments. An active treatment intervention would be required for severe TBI when the ICP was >20 mmHg.

A Retrospective Study of Intracranial Pressure in Head-Injured Patients Undergoing Decompressive Craniectomy: A Comparison of Hypertonic Saline and Mannitol

Objective: The impact of hypertonic saline (HTS) on the control of increased intracranial pressure (ICP) in head-injured patients undergoing decompressive craniectomy (DC) has yet to be established. The current retrospective study was conducted to compare the effect of HTS and mannitol on lowering the ICP burden of these patients.

Methods: We reviewed data on patients who had sustained a traumatic brain injury (TBI) and were admitted to the First People's Hospital of Kunshan between January 1, 2012, and August 31, 2017. Patients who received only one type of hyperosmotic agent, 3% HTS or 20% mannitol, after DC were included. The daily ICP burden (h/day) and response to the hyperosmolar agent were used as primary outcome measures. The numbers of days in the intensive care unit and in the hospital, and the 2-weeks mortality rates were also compared between the groups.

Results: The 30 patients who received 3% HTS only and the 30 who received 20% mannitol only were identified for approximate matching and additional data analyses. The demographic characteristics of the patients in the two groups were comparable, but the daily ICP burden was significantly lower in the HTS group than in the mannitol group (0.89 ± 1.02 h/day vs. 2.11 ± 2.95 h/day, respectively; P = 0.038). The slope of the reduction in ICP in response to a bolus dose at baseline was higher with HTS than with mannitol (P = 0.001). However, the between-group difference in the 2-weeks mortality rates was not statistically significant (2 [HTS] vs. 1 [mannitol]; P = 0.554).

Conclusion: When used in equiosmolar doses, the reduction in the ICP of TBI patients achieved with 3% HTS was superior to that achieved with 20% mannitol after DC. However, this advantage did not seem to confer any additional benefit terms of short-term mortality.

Severe Traumatic Brain Injury Requiring Surgical Decompression in the Young Adult: Factors Influencing Morbidity and Mortality - A Retrospective Analysis

INTRODUCTION

Severe traumatic brain injury (TBI) is a leading cause of morbidity and mortality among young adults. The clinical outcome may also be difficult to predict. We aim to identify the factors predictive of favorable and unfavorable clinical outcomes for youthful patients with severe TBI who have the option of surgical craniotomy or surgical craniectomy.

METHODS

A retrospective review at a single Level II trauma center was conducted, identifying patients aged 18 to 30 years with isolated severe TBI with a mass-occupying lesion requiring emergent (< 6 hours from time of arrival) surgical decompression. Glasgow Coma Scale (GCS) score on arrival, type of surgery performed, mechanism of injury, length of hospital stay, Glasgow Outcome Score (GOS), mortality, and radiographic findings were recorded. A favorable outcome was a GOS of four or five at 30 days post operation, while an unfavorable outcome was GOS of 1 to 3.

RESULTS

Fifty patients were included in the final analysis. Closed head injuries (skull and dura intact), effacement of basal cisterns, disproportional midline shift (MLS), and GCS 3-5 on arrival all correlated with statistically significant higher rate of mortality and poor 30-day functional outcome. All mortalities (6/50 patients) were positive for each of these findings.

CONCLUSIONS

Closed head injuries, the presenting GCS 3-5, the presence of MLS disproportional to the space occupying lesion (SOL), and effacement of basal cisterns on the initial computed tomography of the head all correlated with unfavorable 30-day outcome. Future prospective studies investigating a larger cohort may provide further insight into patients suffering from severe TBI.

A randomised trial to compare the increase in intracranial pressure as correlated with the optic nerve sheath diameter during propofol versus sevoflurane-maintained anesthesia in robot-assisted laparoscopic pelvic surgery

Robot-assisted surgery can cause raised intracranial pressures (ICP) due to steep trendelenburg position and pneumoperitoneum. The choice of anesthetic agents can influence the ICP, which can be measured indirectly by correlating it with the sonographically measured optic nerve sheath diameter (ONSD). In this study, our primary aim was to compare the change from baseline of the ONSD during propofol versus sevoflurane-maintained anesthesia in patients undergoing robotic pelvic surgery. In this prospective, interventional, double-blinded study, we randomised 50 patients into two groups P and S. Subjects in group P received intravenous propofol infusion while those in group S received inhalation sevoflurane for maintenance of anesthesia. The ONSD at fixed intervals was noted as the mean of four values measured using ultrasound in both eyes by two independent anesthesiologists who were blinded to the group allocation. The patient demographics and baseline parameters were similar. The mean maximum rise in ONSD from baseline was 0.01 ± 0.01 cm in group P while it was 0.03 ± 0.01 cm in group S (p = 0.001). Percentage change from baseline in group P was 3.41 ± 1.81% and 8.00 ± 2.95% in group S (p = 0.001). We found a positive correlation between the duration of surgery and the maximum rise in ONSD in group S (p = 0.003), but not in group P. Propofol-based total intravenous anesthesia is more effective than inhalation sevoflurane in attenuating the increase in ICP as correlated with the ONSD during robotic pelvic surgery.Clinical trial registration: Yes; Principal investigator: Nambiath Sujata; Trial number: REF/2016/11/012713 (registered); Trial registry: CTRI- http://ctri.nic.in .

Full Recovery After a Bihemispheric Gunshot Wound to the Head: Case Report, Clinical Management, and Literature Review

BACKGROUND

Nearly 33,600 people die each year in the United States as a result of gunshot wounds (GSWs). Penetrating craniocerebral GSWs are often fatal with a nearly 70% death rate at the scene of the trauma. Overall combined mortality rate for patients who die at the scene or at the hospital is almost 91%. Poor outcome is associated with initial low Glasgow Coma Scale score and bihemispheric and transventricular gunshot trajectory. We summarize current understanding in management, prognostic factors, and survival outcomes in patients with a penetrating GSWs to the head. We report a patient with return to full function despite bihemispheric, multilobar involvement. Full function is defined here as ability to return to previous work and perform activities of daily living.

CASE DESCRIPTION

A 33-year-old man sustained a GSW to the head under unknown circumstances. On initial presentation, he had a Glasgow Coma Scale score of 15. He was verbalizing and communicating but was amnestic for the event. From a left frontal entry wound, the bullet traversed both frontal lobes of the brain reaching the right frontal-parietal junction. Physical examination and vital signs were normal. Appropriate surgical and medical management resulted in complete recovery.

CONCLUSIONS

Craniocerebral GSWs have a high mortality rate and usually require aggressive management. Evaluation of most GSWs requires appropriate imaging studies followed by proactive treatment against infection, seizure, and increased intracranial pressure. Surgical intervention is often necessary and ranges from local wound débridement to craniectomy, decompression, and wound exploration.

Advanced monitoring in traumatic brain injury: microdialysis

PURPOSE OF REVIEW

Here, we review the present state-of-the-art of microdialysis for monitoring patients with severe traumatic brain injury, highlighting the newest developments. Microdialysis has evolved in neurocritical care to become an established bedside monitoring modality that can reveal unique information on brain chemistry.

RECENT FINDINGS

A major advance is recent consensus guidelines for microdialysis use and interpretation. Other advances include insight obtained from microdialysis into the complex, interlinked traumatic brain injury disorders of electrophysiological changes, white matter injury, inflammation and metabolism.

SUMMARY

Microdialysis has matured into being a standard clinical monitoring modality that takes its place alongside intracranial pressure and brain tissue oxygen tension measurement in specialist neurocritical care centres, as well as being a research tool able to shed light on brain metabolism, inflammation, therapeutic approaches, blood-brain barrier transit and drug effects on downstream targets. Recent consensus on microdialysis monitoring is paving the way for improved neurocritical care protocols. Furthermore, there is scope for future improvements both in terms of the catheters and microdialysate analyser technology, which may further enhance its applicability.

Intracranial pressure monitoring

Brain specific monitoring enables detection and prevention of secondary cerebral insults, especially in the injured brain, thereby preventing permanent neurological damage. Intracranial pressure (ICP) monitoring is widely used in various neurological, neurosurgical and even medical conditions, both intraoperatively and in critical care, to improve patient outcome. It is especially useful in patients with traumatic brain injury, as a robust predictor of cerebral perfusion, and can help to guide therapy and assess long-term prognosis. Intraventricular catheters remain the gold standard for ICP monitoring, as they are the most reliable, accurate and cost-effective, and allow therapeutic cerebrospinal fluid drainage. Newer fibreoptic catheter tip and microchip transducer techniques have revolutionised ICP monitoring, with their ease of insertion in patients with narrow ventricles, and reduced risk of infection and haemorrhage. Furthermore, non-invasive methods of ICP monitoring, such as transcranial Doppler, optic nerve sheath diameter, etc., have emerged as promising techniques for screening patients with raised ICP in settings where invasive techniques are either not feasible (patients with severe coagulopathy) or not available (setups without access to a neurosurgeon). Therefore, ICP monitoring, as a part of multi-modality neuromonitoring, is a useful tool in the armamentarium of the neuro-intensivist in decreasing morbidity and mortality of critically ill neurological patients.

Intraoperative Secondary Insults During Orthopedic Surgery in Traumatic Brain Injury

BACKGROUND

Secondary insults worsen outcomes after traumatic brain injury (TBI). However, data on intraoperative secondary insults are sparse. The primary aim of this study was to examine the prevalence of intraoperative secondary insults during orthopedic surgery after moderate-severe TBI. We also examined the impact of intraoperative secondary insults on postoperative head computed tomographic scan, intracranial pressure (ICP), and escalation of care within 24 hours of surgery.

MATERIALS AND METHODS

We reviewed medical records of TBI patients 18 years and above with Glasgow Coma Scale score <13 who underwent single orthopedic surgery within 2 weeks of TBI. Secondary insults examined were: systemic hypotension (systolic blood pressure<90 mm Hg), intracranial hypertension (ICP>20 mm Hg), cerebral hypotension (cerebral perfusion pressure<50 mm Hg), hypercarbia (end-tidal CO2>40 mm Hg), hypocarbia (end-tidal CO2<30 mm Hg in absence of intracranial hypertension), hyperglycemia (glucose>200 mg/dL), hypoglycemia (glucose<60 mg/dL), and hyperthermia (temperature >38°C).

RESULTS

A total of 78 patients (41 [18 to 81] y, 68% male) met the inclusion criteria. The most common intraoperative secondary insults were systemic hypotension (60%), intracranial hypertension and cerebral hypotension (50% and 45%, respectively, in patients with ICP monitoring), hypercarbia (32%), and hypocarbia (29%). Intraoperative secondary insults were associated with worsening of head computed tomography, postoperative decrease of Glasgow Coma Scale score by ≥2, and escalation of care. After Bonferroni correction, association between cerebral hypotension and postoperative escalation of care remained significant (P<0.001).

CONCLUSIONS

Intraoperative secondary insults were common during orthopedic surgery in patients with TBI and were associated with postoperative escalation of care. Strategies to minimize intraoperative secondary insults are needed.