"NeuroVanguard": a contemporary strategy in neuromonitoring for severe adult brain injury patients

Severe acute brain injuries, stemming from trauma, ischemia or hemorrhage, remain a significant global healthcare concern due to their association with high morbidity and mortality rates. Accurate assessment of secondary brain injuries severity is pivotal for tailor adequate therapies in such patients. Together with neurological examination and brain imaging, monitoring of systemic secondary brain injuries is relatively straightforward and should be implemented in all patients, according to local resources. Cerebral secondary injuries involve factors like brain compliance loss, tissue hypoxia, seizures, metabolic disturbances and neuroinflammation. In this viewpoint, we have considered the combination of specific noninvasive and invasive monitoring tools to better understand the mechanisms behind the occurrence of these events and enhance treatment customization, such as intracranial pressure monitoring, brain oxygenation assessment and metabolic monitoring. These tools enable precise intervention, contributing to improved care quality for severe brain injury patients. The future entails more sophisticated technologies, necessitating knowledge, interdisciplinary collaboration and resource allocation, with a focus on patient-centered care and rigorous validation through clinical trials.

Effects of positive end-expiratory pressure on intracranial pressure, cerebral perfusion pressure, and brain oxygenation in acute brain injury: Friend or foe? A scoping review

Background

Patients with acute brain injury (ABI) are a peculiar population because ABI does not only affect the brain but also other organs such as the lungs, as theorized in brain-lung crosstalk models. ABI patients often require mechanical ventilation (MV) to avoid the complications of impaired respiratory function that can follow ABI; MV should be settled with meticulousness owing to its effects on the intracranial compartment, especially regarding positive end-expiratory pressure (PEEP). This scoping review aimed to (1) describe the physiological basis and mechanisms related to the effects of PEEP in ABI; (2) examine how clinical research is conducted on this topic; (3) identify methods for setting PEEP in ABI; and (4) investigate the impact of the application of PEEP in ABI on the outcome.

Methods

The five-stage paradigm devised by Peters et al. and expanded by Arksey and O'Malley, Levac et al., and the Joanna Briggs Institute was used for methodology. We also adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension criteria. Inclusion criteria: we compiled all scientific data from peer-reviewed journals and studies that discussed the application of PEEP and its impact on intracranial pressure, cerebral perfusion pressure, and brain oxygenation in adult patients with ABI. Exclusion criteria: studies that only examined a pediatric patient group (those under the age of 18), experiments conducted solely on animals; studies without intracranial pressure and/or cerebral perfusion pressure determinations, and studies with incomplete information. Two authors searched and screened for inclusion in papers published up to July 2023 using the PubMed-indexed online database. Data were presented in narrative and tubular form.

Results

The initial search yielded 330 references on the application of PEEP in ABI, of which 36 met our inclusion criteria. PEEP has recognized beneficial effects on gas exchange, but it produces hemodynamic changes that should be predicted to avoid undesired consequences on cerebral blood flow and intracranial pressure. Moreover, the elastic properties of the lungs influence the transmission of the forces applied by MV over the brain so they should be taken into consideration. Currently, there are no specific tools that can predict the effect of PEEP on the brain, but there is an established need for a comprehensive monitoring approach for these patients, acknowledging the etiology of ABI and the measurable variables to personalize MV.

Conclusion

PEEP can be safely used in patients with ABI to improve gas exchange keeping in mind its potentially harmful effects, which can be predicted with adequate monitoring supported by bedside non-invasive neuromonitoring tools.

Neurophysiologic Features Reflecting Brain Injury During Pediatric ECMO Support

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) provides lifesaving support to critically ill patients who experience refractory cardiopulmonary failure but carries a high risk for acute brain injury. We aimed to identify characteristics reflecting acute brain injury in children requiring ECMO support.

METHODS

This is a prospective observational study from 2019 to 2022 of pediatric ECMO patients undergoing neuromonitoring, including continuous electroencephalography, cerebral oximetry, and transcranial Doppler ultrasound (TCD). The primary outcome was acute brain injury. Clinical and neuromonitoring characteristics were collected. Multivariate logistic regression was implemented to model odds ratios (ORs) and identify the combined characteristics that best discriminate risk of acute brain injury using the area under the receiver operating characteristic curve.

RESULTS

Seventy-five pediatric patients requiring ECMO support were enrolled in this study, and 62 underwent neuroimaging or autopsy evaluations. Of these 62 patients, 19 experienced acute brain injury (30.6%), including seven (36.8%) with arterial ischemic stroke, four (21.1%) with hemorrhagic stroke, seven with hypoxic-ischemic brain injury (36.8%), and one (5.3%) with both arterial ischemic stroke and hypoxic-ischemic brain injury. A univariate analysis demonstrated acute brain injury to be associated with maximum hourly seizure burden (p = 0.021), electroencephalographic suppression percentage (p = 0.022), increased interhemispheric differences in electroencephalographic total power (p = 0.023) and amplitude (p = 0.017), and increased differences in TCD Thrombolysis in Brain Ischemia (TIBI) scores between bilateral middle cerebral arteries (p = 0.023). Best subset model selection identified increased seizure burden (OR = 2.07, partial R2 = 0.48, p = 0.013), increased quantitative electroencephalographic interhemispheric amplitude differences (OR = 2.41, partial R2 = 0.48, p = 0.013), and increased interhemispheric TCD TIBI score differences (OR = 4.66, partial R2 = 0.49, p = 0.006) to be independently associated with acute brain injury (area under the receiver operating characteristic curve = 0.92).

CONCLUSIONS

Increased seizure burden and increased interhemispheric differences in both quantitative electroencephalographic amplitude and TCD MCA TIBI scores are independently associated with acute brain injury in children undergoing ECMO support.

Ten good reasons to consider gastrointestinal function after acute brain injury

The brain-gut axis represents a bidirectional communication linking brain function with the gastrointestinal (GI) system. This interaction comprises a top-down communication from the brain to the gut, and a bottom-up communication from the gut to the brain, including neural, endocrine, immune, and humoral signaling. Acute brain injury (ABI) can lead to systemic complications including GI dysfunction. Techniques for monitoring GI function are currently few, neglected, and many under investigation. The use of ultrasound could provide a measure of gastric emptying, bowel peristalsis, bowel diameter, bowel wall thickness and tissue perfusion. Despite novel biomarkers represent a limitation in clinical practice, intra-abdominal pressure (IAP) is easy-to-use and measurable at bedside. Increased IAP can be both cause and consequence of GI dysfunction, and it can influence cerebral perfusion pressure and intracranial pressure via physiological mechanisms. Here, we address ten good reasons to consider GI function in patients with ABI, highlighting the importance of its assessment in neurocritical care.

Multimodal monitoring in patients with acute brain injury - A survey from critical care providers

BACKGROUND

Multimodal neuromonitoring (MMM) aims to improve outcome after acute brain injury, and thus admission in specialized Neurocritical Care Units with potential access to MMM is necessary. Various invasive and noninvasive modalities have been developed, however there is no strong evidence to support monitor combinations nor is there a known standardized approach. The goal of this study is to identify the most used invasive and non-invasive neuromonitoring modalities in daily practice as well as ubiquitousness of MMM standardization.

METHODS

In order to investigate current availability and protocolized implementation of MMM among neurocritical care units in US and non-US intensive care units, we designed a cross-sectional survey consisting of a self-administered online questionnaire of 20 closed-ended questions disseminated by the Neurocritical Care Society.

RESULTS

Twenty-one critical care practitioners responded to our survey with a 76% completion rate. The most commonly utilized non-invasive neuromonitoring modalities were continuous electroencephalography followed by transcranial doppler. The most common invasive modalities were external ventricular drain followed by parenchymal intracranial pressure (ICP) monitoring. MMM is most utilized in patients with subarachnoid hemorrhage and there were no differences regarding established institutional protocol, 24-h cEEG availability and invasive monitor placement between teaching and non-teaching hospitals. MMM is considered standard of care in 28% of responders' hospitals, whereas in 26.7% it is deemed experimental and only done as part of clinical trials. Only 26.7% hospitals use a computerized data integration system.

CONCLUSION

Our survey revealed overall limited use of MMM with no established institutional protocols among institutions. Ongoing research and further standardization of MMM will clarify its benefit to patients suffering from severe brain injury.

Temperature management in acute brain injury: A narrative review

Temperature management has been used in patients with acute brain injury resulting from different conditions, such as post-cardiac arrest hypoxic-ischaemic insult, acute ischaemic stroke, and severe traumatic brain injury. However, current evidence offers inconsistent and often contradictory results regarding the clinical benefit of this therapeutic strategy on mortality and functional outcomes. Current guidelines have focused mainly on active prevention and treatment of fever, while therapeutic hypothermia (TH) has fallen into disuse, although doubts persist as to its effectiveness according to the method of application and appropriate patient selection. This narrative review presents the most relevant clinical evidence on the effects of TH in patients with acute neurological damage, and the pathophysiological concepts supporting its use.

Ventriculostomy-associated infection (VAI) in patients with acute brain injury-a retrospective study

BACKGROUND

Ventriculostomy-associated infection (VAI) is common after external ventricular drains (EVD) insertion but is difficult to diagnose in patients with acute brain injury. Previously, we proposed a set of criteria for ruling out VAI in traumatic brain injury. This study aimed to validate these criteria. For exploratory purposes, we sought to develop and validate a score for VAI risk assessment in patients with different types of severe acute brain injury.

METHODS

This retrospective cohort study included adults with acute brain injury who received an EVD and in whom CSF samples were taken over a period of 57 months. As standard non-coated bolt-connected EVDs were used. The predictive performance of biomarkers was analyzed as defined previously. A multivariable regression model was performed with five variables.

RESULTS

A total of 683 patients with acute brain injury underwent EVD placement and had 1272 CSF samples; 92 (13.5%) patients were categorized as culture-positive VAI, 130 (19%) as culture-negative VAI, and 461 (67.5%) as no VAI. A low CSF WBC/RBC ratio (< 0.037), high CSF/plasma glucose ratio (> 0.6), and low CSF protein (< 0.5g/L) showed a positive predictive value of 0.09 (95%CI, 0.05-0.13). In the multivariable logistic regression model, days to sample (OR 1.09; 95%CI, 1.03-1.16) and CSF WBC/RBC ratio (OR 34.86; 95%CI, 3.94-683.15) were found to predict VAI.

CONCLUSION

In patients with acute brain injury and an EVD, our proposed combined cut-off for ruling out VAI performed satisfactorily. Days to sample and CSF WBC/RBC ratio were found independent predictors for VAI in the multivariable logistic regression model.

Resting-State Functional Magnetic Resonance Imaging Network Association With Mortality, Epilepsy, Cognition, and Motor Two-Year Outcomes in Suspected Severe Neonatal Acute Brain Injury

BACKGROUND AND OBJECTIVES

In acute brain injury of neonates, resting-state functional magnetic resonance imaging (MRI) (RS) showed incremental association with consciousness, mortality, cognitive and motor development, and epilepsy, with correction for multiple comparisons, at six months postgestation in neonates with suspected acute brain injury (ABI). However, there are relatively few developmental milestones at six months to benchmark against, thus, we extended this cohort study to evaluate two-year outcomes.

METHODS

In 40 consecutive neonates with ABI and RS, ordinal scores of resting-state networks; MRI, magnetic resonance spectroscopy, and electroencephalography; and up to 42-month outcomes of mortality, general and motor development, Pediatric Cerebral Performance Category Scale (PCPC), and epilepsy informed associations between tests and outcomes.

RESULTS

Mean gestational age was 37.8 weeks, 68% were male, and 60% had hypoxic-ischemic encephalopathy. Three died in-hospital, four at six to 42 months, and five were lost to follow-up. Associations included basal ganglia network with PCPC (P = 0.0003), all-mortality (P = 0.005), and motor (P = 0.0004); language/frontoparietal network with developmental delay (P = 0.009), PCPC (P = 0.006), and all-mortality (P = 0.01); default mode network with developmental delay (P = 0.003), PCPC (P = 0.004), neonatal intensive care unit mortality (P = 0.01), and motor (P = 0.009); RS seizure onset zone with epilepsy (P = 0.01); and anatomic MRI with epilepsy (P = 0.01).

CONCLUSION

For the first time, at any age, resting state functional MRI in ABI is associated with long-term epilepsy and RSNs predicted mortality in neonates. Severity of RSN abnormality was associated with incrementally worsened neurodevelopment including cognition, language, and motor function over two years.

Twelve controversial questions in aneurysmal subarachnoid hemorrhage

Critical care management of aneurysmal subarachnoid hemorrhage (aSAH) remains a major challenge. Despite the recent publication of guidelines from the American Heart Association/American Stroke Association and the Neurocritical Care Society, there are many controversial questions in the intensive care unit (ICU) management of this population. The authors provide an analysis of common issues in the ICU and provide guidance on the daily management of this specific population of neurocritical care patients.

Paroxysmal Sympathetic Hyperactivity after Traumatic Brain Injury: Current Understanding and Therapeutic Options

How to cite this article: Nasa P, Majeed NA, Juneja D. Paroxysmal Sympathetic Hyperactivity after Traumatic Brain Injury: Current Understanding and Therapeutic Options. Indian J Crit Care Med 2024;28(2):97-99.

Cognitive Motor Dissociation: Gap Analysis and Future Directions

BACKGROUND

Patients with disorders of consciousness who are behaviorally unresponsive may demonstrate volitional brain responses to motor imagery or motor commands detectable on functional magnetic resonance imaging or electroencephalography. This state of cognitive motor dissociation (CMD) may have prognostic significance.

METHODS

The Neurocritical Care Society's Curing Coma Campaign identified an international group of experts who convened in a series of monthly online meetings between September 2021 and April 2023 to examine the science of CMD and identify key knowledge gaps and unmet needs.

RESULTS

The group identified major knowledge gaps in CMD research: (1) lack of information about patient experiences and caregiver accounts of CMD, (2) limited epidemiological data on CMD, (3) uncertainty about underlying mechanisms of CMD, (4) methodological variability that limits testing of CMD as a biomarker for prognostication and treatment trials, (5) educational gaps for health care personnel about the incidence and potential prognostic relevance of CMD, and (6) challenges related to identification of patients with CMD who may be able to communicate using brain-computer interfaces.

CONCLUSIONS

To improve the management of patients with disorders of consciousness, research efforts should address these mechanistic, epidemiological, bioengineering, and educational gaps to enable large-scale implementation of CMD assessment in clinical practice.

Acute brain injury increases pulmonary capillary permeability via sympathetic activation-mediated high fluid shear stress and destruction of the endothelial glycocalyx layer

Neurogenic pulmonary edema secondary to acute brain injury (ABI) is a common and fatal disease condition. However, the pathophysiology of brain-lung interactions is incompletely understood. This study aims to investigate whether sympathetic activation-mediated high fluid shear stress after ABI would damage pulmonary endothelial glycocalyx thus leading to increased pulmonary capillary permeability. The tricuspid annular plane systolic excursion (TAPSE) was detected in a rat model of controlled cortical impact (CCI) and CCI + transection of the cervical sympathetic trunk (TCST). Changes in pulmonary capillary permeability were assessed by analyzing the Evans blue, measuring the dry/wet weight ratio of the lungs and altering protein levels in the bronchoalveolar lavage fluid (BALF). The parallel-plate flow chamber system was used to simulate the fluid shear stress in vitro. Western blotting and immunofluorescence staining were used to determine the expression levels of hyaluronan-binding protein (CEMIP), syndecan-1 and tight junction proteins (TJPs, including claudin-5 and occludin). TCST could restrain cardiac overdrive and sympathetic activation in a rat model of CCI. Compared to the CCI group, the CCI + TCST group showed a reduction of CEMPI (which degrades hyaluronic acid), along with an increase of syndecan-1 and TJPs. CCI + TCST group presented decreasing pulmonary capillary permeability. In vitro, high shear stress (HSS) increased the expression of CEMIP and reduced syndecan-1 and TJPs, which was coordinated with the results in vivo. Our findings show that sympathetic activation-mediated high fluid shear stress after ABI would damage pulmonary endothelial glycocalyx thus leading to increased pulmonary capillary permeability.

Mastering the brain in critical conditions: an update

Acute brain injuries, such as traumatic brain injury and ischemic and hemorragic stroke, are a leading cause of death and disability worldwide. While characterized by clearly distict primary events-vascular damage in strokes and biomechanical damage in traumatic brain injuries-they share common secondary injury mechanisms influencing long-term outcomes. Growing evidence suggests that a more personalized approach to optimize energy substrate delivery to the injured brain and prognosticate towards families could be beneficial. In this context, continuous invasive and/or non-invasive neuromonitoring, together with clinical evaluation and neuroimaging to support strategies that optimize cerebral blood flow and metabolic delivery, as well as approaches to neuroprognostication are gaining interest. Recently, the European Society of Intensive Care Medicine organized a 2-day course focused on a practical case-based clinical approach of acute brain-injured patients in different scenarios and on future perspectives to advance the management of this population. The aim of this manuscript is to update clinicians dealing with acute brain injured patients in the intensive care unit, describing current knowledge and clinical practice based on the insights presented during this course.

Selective digestive tract decontamination in critically ill adults with acute brain injuries: a post hoc analysis of a randomized clinical trial

PURPOSE

The aim of this study was to determine whether selective decontamination of the digestive tract (SDD) reduces in-hospital mortality in mechanically ventilated critically ill adults admitted to the intensive care unit (ICU) with acute brain injuries or conditions.

METHODS

We carried out a post hoc analysis from a crossover, cluster randomized clinical trial. ICUs were randomly assigned to adopt or not to adopt a SDD strategy for two alternating 12-month periods, separated by a 3-month inter-period gap. Patients in the SDD group (n = 2791; 968 admitted to the ICU with an acute brain injury) received a 6-hourly application of an oral paste and administration of a gastric suspension containing colistin, tobramycin, and nystatin for the duration of mechanical ventilation, plus a 4-day course of an intravenous antibiotic with a suitable antimicrobial spectrum. Patients in the control group (n = 3191; 1093 admitted to the ICU with an acute brain injury) received standard care. The primary outcome was in-hospital mortality within 90 days. There were four secondary clinical outcomes: death in ICU, ventilator-, ICU- and hospital-free days to day 90.

RESULTS

Of 2061 patients with acute brain injuries (mean age, 55.8 years; 36.4% women), all completed the trial. In patients with acute brain injuries, there were 313/968 (32.3%) and 415/1093 (38%) in-hospital deaths in the SDD and standard care groups (unadjusted odds ratio [OR], 0.76, 95% confidence interval [CI] 0.63-0.92; p = 0.004). The use of SDD was associated with statistically significant improvements in the four clinical secondary outcomes compared to standard care. There was no significant heterogeneity of treatment effect between patients with and without acute brain injuries (interaction p = 0.22).

CONCLUSIONS

In this post hoc analysis of a randomized clinical trial in critically ill patients with acute brain injuries receiving mechanical ventilation, the use of SDD significantly reduced in-hospital mortality in patients compared to standard care without SDD. These findings require confirmation.

Critical Closing Pressure and Cerebrovascular Resistance Responses to Intracranial Pressure Variations in Neurocritical Patients

BACKGROUND

Critical closing pressure (CrCP) and resistance-area product (RAP) have been conceived as compasses to optimize cerebral perfusion pressure (CPP) and monitor cerebrovascular resistance, respectively. However, for patients with acute brain injury (ABI), the impact of intracranial pressure (ICP) variability on these variables is poorly understood. The present study evaluates the effects of a controlled ICP variation on CrCP and RAP among patients with ABI.

METHODS

Consecutive neurocritical patients with ICP monitoring were included along with transcranial Doppler and invasive arterial blood pressure monitoring. Internal jugular veins compression was performed for 60 s for the elevation of intracranial blood volume and ICP. Patients were separated in groups according to previous intracranial hypertension severity, with either no skull opening (Sk1), neurosurgical mass lesions evacuation, or decompressive craniectomy (DC) (patients with DC [Sk3]).

RESULTS

Among 98 included patients, the correlation between change (Δ) in ICP and the corresponding ΔCrCP was strong (group Sk1 r = 0.643 [p = 0.0007], group with neurosurgical mass lesions evacuation r = 0.732 [p < 0.0001], and group Sk3 r = 0.580 [p = 0.003], respectively). Patients from group Sk3 presented a significantly higher ΔRAP (p = 0.005); however, for this group, a higher response in mean arterial pressure (change in mean arterial pressure p = 0.034) was observed. Exclusively, group Sk1 disclosed reduction in ICP before internal jugular veins compression withholding.

CONCLUSIONS

This study elucidates that CrCP reliably changes in accordance with ICP, being useful to indicate ideal CPP in neurocritical settings. In the early days after DC, cerebrovascular resistance seems to remain elevated, despite exacerbated arterial blood pressure responses in efforts to maintain CPP stable. Patients with ABI with no need of surgical procedures appear to remain with more effective ICP compensatory mechanisms when compared with those who underwent neurosurgical interventions.

Doing More with Less on Intracranial Pressure Monitoring

BACKGROUND

Intracranial pressure (ICP) management based on predetermined thresholds is not accurate in light of recent research on cerebrovascular physiology. Interpersonal and intrapersonal variations will lead ICP elevations to reach individualized thresholds for intracranial compliance impairment from one subject to another. Therefore reuniting the modern techniques of neuromonitoring besides ICP enables practitioners to have a more whole picture in anticipating neuro worsening and improving timing in decision making.

METHODS

Brief literature review.

RESULTS

For the severely brain-injured patient, current evidence indicates a personalized and physiology-based multimodal monitoring care to be required rather than decision making according to ICP predetermined cut-offs.

CONCLUSIONS

The authors' point of view is of particular importance for regions with resource heterogeneity and scarcity, where ICP monitoring is not available for all those in need and noninvasive techniques may provide a surrogate approach. If physicians who deal with acute-brain-injured patients in lower-resource areas understand that several tools besides ICP may improve their practice, it is possible to reduce acute brain injury morbimortality.

Gastrointestinal Motility Disorders Correlate with Intracranial Bleeding, Opioid Use, and Brainstem Edema in Neurosurgical Patients

BACKGROUND

Gastrointestinal (GI) motility disorders may be directly associated with the intensity of acute brain injury, edema of the brainstem, and opioid use in neurosurgical patients.

METHODS

In this retrospective study, patient demographic characteristics, computed tomography (CT) scans, the occurrence of gastroparesis, constipation, and opioid use were registered during the intensive care unit (ICU) stay and correlated with days of mechanical ventilation, length of ICU stay, and survival. Gastroparesis was defined as residual gastric volume > 250 mL per day, and constipation was defined as the absence of stool for 3 days or more during the ICU stay.

RESULTS

Of 207 neurosurgical patients screened, 69 adult patients who spent more than 4 days in the ICU were included in the study. Gastroparesis was observed in 48 (69.6%) patients, constipation was observed in 67 (97.1%) patients, and stress ulcers were observed in 4 (5.8%) patients. Patients with brainstem edema (n = 57, 82.6%) had the first stool evacuation later compared with patients with no edema (8 [interquartile range (IQR) 5.25-9.75] vs. 3.5 [IQR 2.25-4] days; P < 0.001). In the logistic regression analysis, factors that were associated with GI dysmotility were central nervous system (CNS) bleeding (odds ratio [OR] 5.1, 95% confidence interval [CI] 1.26-20.8, P = 0.02), opioid use > 19.3 morphine equivalents (ME) per day (OR 5.37, 95% CI 1.1-27.1, P = 0.04), and brainstem edema (OR 4.9, 95% CI 1.1-21.6, P = 0.04). A receiver operating characteristic curve analysis confirmed that the cutoff value of > 6.78 ME per day was a good predictor determining GI dysmotility, with 89.5% sensitivity and 72.7% specificity (95% CI 0.67-0.88, area under the curve 0.784, Youden index 0.62, P = 0.001). Poor survival correlated with lower Glasgow Coma Score values (ρ =  - 520, P < 0.001), CNS bleeding (ρ = 0.393, P < 0.001), associated cardiac diseases (ρ = 0.279, P < 0.001), and cardiorespiratory arrest on admission (ρ = 0.315, P < 0.001), but not with GI dysmotility (ρ = 0.175, P = 0.402).

CONCLUSIONS

Significant correlation was registered between brainstem edema, gastrointestinal dysmotility, and opioids. CNS bleeding was the most important single factor influencing GI dysmotility. Further studies with opioid and nonopioid sedation may distinguish the influence of acute brain lesions versus drugs on GI dysmotility.

Massage Therapy May be Safe and Reduce Pain in Critically Ill Patients with Acute Neurological Injury: a Case Control Study

Purpose

Massage therapy is an important adjunctive treatment for physiologic and psychologic symptoms and has been shown to benefit patients among a wide variety of patient populations.

Setting

Few studies have investigated the utility of massage therapy in the general ICU setting, and even fewer have done so in the neurological ICU (NeuroICU).

Research Design

If massage therapy was determined to improve objective outcomes-or even subjective outcomes in the absence of harm-massage may be more readily employed as a complementary therapy, particularly in the ICU setting or in patients with acute neurological injury.

Intervention

This pilot study aimed to assess the safety of massage in the neurocritical care unit and its impact on patient vital signs, subjective pain assessment, and other clinical outcomes.

Participants

Twenty-one patients who received massage therapy during admission to the neurocritical care service were compared to matched controls in a retrospective case control study design.

Results

We found a statistically significant reduction in pain scores among patients with acute neurological injury who received massage therapy. There was no statistical difference in hospital length of stay, discharge destination, in-hospital mortality, adverse events, or incidence/duration of delirium between patients who received massage therapy and those who did not. No adverse events were ascribed to the massage therapy when evaluated by blinded neurocritical care specialists.

Conclusion

This study found that massage therapy may be safe for many patients in the NeuroICU and may offer additional subjective benefits.

Respiratory challenges and ventilatory management in different types of acute brain-injured patients

Acute brain injury (ABI) covers various clinical entities that may require invasive mechanical ventilation (MV) in the intensive care unit (ICU). The goal of MV, which is to protect the lung and the brain from further injury, may be difficult to achieve in the most severe forms of lung or brain injury. This narrative review aims to address the respiratory issues and ventilator management, specific to ABI patients in the ICU.

Nonpharmacological modulation of cortical spreading depolarization

AIMS

Cortical spreading depolarization (CSD) is a wave of pathologic neuronal dysfunction that spreads through cerebral gray matter, causing neurologic disturbance in migraine and promoting lesion development in acute brain injury. Pharmacologic interventions have been found to be effective in migraine with aura, but their efficacy in acutely injured brains may be limited. This necessitates the assessment of possible adjunctive treatments, such as nonpharmacologic methods. This review aims to summarize currently available nonpharmacological techniques for modulating CSDs, present their mechanisms of action, and provide insight and future directions for CSD treatment.

MAIN METHODS

A systematic literature review was performed, generating 22 articles across 3 decades. Relevant data is broken down according to method of treatment.

KEY FINDINGS

Both pharmacologic and nonpharmacologic interventions can mitigate the pathological impact of CSDs via shared molecular mechanisms, including modulating K⁺/Ca²⁺/Na⁺/Cl^- ion channels and NMDA, GABA_A, serotonin, and CGRP ligand-based receptors and decreasing microglial activation. Preclinical evidence suggests that nonpharmacologic interventions, including neuromodulation, physical exercise, therapeutic hypothermia, and lifestyle changes can also target unique mechanisms, such as increasing adrenergic tone and myelination and modulating membrane fluidity, which may lend broader modulatory effects. Collectively, these mechanisms increase the electrical initiation threshold, increase CSD latency, slow CSD velocity, and decrease CSD amplitude and duration.

SIGNIFICANCE

Given the harmful consequences of CSDs, limitations of current pharmacological interventions to inhibit CSDs in acutely injured brains, and translational potentials of nonpharmacologic interventions to modulate CSDs, further assessment of nonpharmacologic modalities and their mechanisms to mitigate CSD-related neurologic dysfunction is warranted.

Lower Oxygen Tension and Intracranial Hemorrhage in Veno-venous Extracorporeal Membrane Oxygenation

INTRODUCTION AND METHODS

We examined the relationship between 24-h pre- and post-cannulation arterial oxygen tension (PaO2) and arterial carbon dioxide tension (PaCO2) and subsequent acute brain injury (ABI) in patients receiving veno-venous extracorporeal membrane oxygenation (VV-ECMO) with granular arterial blood gas (ABG) data and institutional standardized neuromonitoring.

RESULTS

Eighty-nine patients underwent VV-ECMO (median age = 50, 63% male). Twenty (22%) patients experienced ABI; intracranial hemorrhage (ICH) was the most common diagnosis (n = 14, 16%). Lower post-cannulation PaO2 levels were significantly associated with ICH (66 vs. 81 mmHg, p = 0.007) and a post-cannulation PaO2 level < 70 mmHg was more frequent in these patients (71% vs. 33%, p = 0.007). PaCO2 parameters were not associated with ABI. By multivariable logistic regression, hypoxemia post-cannulation increased the odds of ICH (OR = 5.06, 95% CI:1.41-18.17; p = 0.01).

CONCLUSION

In summary, lower oxygen tension in the 24-h post-cannulation was associated with ICH development. The precise roles of peri-cannulation ABG changes deserve further investigation, as they may influence the management of VV-ECMO patients.

Early Low Pulse Pressure in VA-ECMO Is Associated with Acute Brain Injury

BACKGROUND

Pulse pressure is a dynamic marker of cardiovascular function and is often impaired in patients on venoarterial extracorporeal membrane oxygenation (VA-ECMO). Pulsatile blood flow also serves as a regulator of vascular endothelium, and continuous-flow mechanical circulatory support can lead to endothelial dysfunction. We explored the impact of early low pulse pressure on occurrence of acute brain injury (ABI) in VA-ECMO.

METHODS

We conducted a retrospective analysis of adults with VA-ECMO at a tertiary care center between July 2016 and January 2021. Patients underwent standardized multimodal neuromonitoring throughout ECMO support. ABI included intracranial hemorrhage, ischemic stroke, hypoxic ischemic brain injury, cerebral edema, seizure, and brain death. Blood pressures were recorded every 15 min. Low pulse pressure was defined as a median pulse pressure < 20 mm Hg in the first 12 h of ECMO. Multivariable logistic regression was performed to investigate the association between pulse pressure and ABI.

RESULTS

We analyzed 5138 blood pressure measurements from 123 (median age 63; 63% male) VA-ECMO patients (54% peripheral; 46% central cannulation), of whom 41 (33%) experienced ABI. Individual ABIs were as follows: ischemic stroke (n = 18, 15%), hypoxic ischemic brain injury (n = 14, 11%), seizure (n = 8, 7%), intracranial hemorrhage (n = 7, 6%), cerebral edema (n = 7, 6%), and brain death (n = 2, 2%). Fifty-eight (47%) patients had low pulse pressure. In a multivariable model adjusting for preselected covariates, including cannulation strategy (central vs. peripheral), lactate on ECMO day 1, and left ventricle venting strategy, low pulse pressure was independently associated with ABI (adjusted odds ratio 2.57, 95% confidence interval 1.05-6.24). In a model with the same covariates, every 10-mm Hg decrease in pulse pressure was associated with 31% increased odds of ABI (95% confidence interval 1.01-1.68). In a sensitivity analysis model adjusting for systolic pressure, pulse pressure remained significantly associated with ABI.

CONCLUSIONS

Early low pulse pressure (< 20 mm Hg) was associated with ABI in VA-ECMO patients. Low pulse pressure may serve as a marker of ABI risk, which necessitates close neuromonitoring for early detection.

Utilization of mechanical power and associations with clinical outcomes in brain injured patients: a secondary analysis of the extubation strategies in neuro-intensive care unit patients and associations with outcome (ENIO) trial

BACKGROUND

There is insufficient evidence to guide ventilatory targets in acute brain injury (ABI). Recent studies have shown associations between mechanical power (MP) and mortality in critical care populations. We aimed to describe MP in ventilated patients with ABI, and evaluate associations between MP and clinical outcomes.

METHODS

In this preplanned, secondary analysis of a prospective, multi-center, observational cohort study (ENIO, NCT03400904), we included adult patients with ABI (Glasgow Coma Scale ≤ 12 before intubation) who required mechanical ventilation (MV) ≥ 24 h. Using multivariable log binomial regressions, we separately assessed associations between MP on hospital day (HD)1, HD3, HD7 and clinical outcomes: hospital mortality, need for reintubation, tracheostomy placement, and development of acute respiratory distress syndrome (ARDS).

RESULTS

We included 1217 patients (mean age 51.2 years [SD 18.1], 66% male, mean body mass index [BMI] 26.3 [SD 5.18]) hospitalized at 62 intensive care units in 18 countries. Hospital mortality was 11% (n = 139), 44% (n = 536) were extubated by HD7 of which 20% (107/536) required reintubation, 28% (n = 340) underwent tracheostomy placement, and 9% (n = 114) developed ARDS. The median MP on HD1, HD3, and HD7 was 11.9 J/min [IQR 9.2-15.1], 13 J/min [IQR 10-17], and 14 J/min [IQR 11-20], respectively. MP was overall higher in patients with ARDS, especially those with higher ARDS severity. After controlling for same-day pressure of arterial oxygen/fraction of inspired oxygen (P/F ratio), BMI, and neurological severity, MP at HD1, HD3, and HD7 was independently associated with hospital mortality, reintubation and tracheostomy placement. The adjusted relative risk (aRR) was greater at higher MP, and strongest for: mortality on HD1 (compared to the HD1 median MP 11.9 J/min, aRR at 17 J/min was 1.22, 95% CI 1.14-1.30) and HD3 (1.38, 95% CI 1.23-1.53), reintubation on HD1 (1.64; 95% CI 1.57-1.72), and tracheostomy on HD7 (1.53; 95%CI 1.18-1.99). MP was associated with the development of moderate-severe ARDS on HD1 (2.07; 95% CI 1.56-2.78) and HD3 (1.76; 95% CI 1.41-2.22).

CONCLUSIONS

Exposure to high MP during the first week of MV is associated with poor clinical outcomes in ABI, independent of P/F ratio and neurological severity. Potential benefits of optimizing ventilator settings to limit MP warrant further investigation.

Cerebro-spinal fluid glucose and lactate concentrations changes in response to therapies in patIents with primary brain injury: the START-TRIP study

INTRODUCTION

Altered levels of cerebrospinal fluid (CSF) glucose and lactate concentrations are associated with poor outcomes in acute brain injury patients. However, no data on changes in such metabolites consequently to therapeutic interventions are available. The aim of the study was to assess CSF glucose-to-lactate ratio (CGLR) changes related to therapies aimed at reducing intracranial pressure (ICP).

METHODS

A multicentric prospective cohort study was conducted in 12 intensive care units (ICUs) from September 2017 to March 2022. Adult (> 18 years) patients admitted after an acute brain injury were included if an external ventricular drain (EVD) for intracranial pressure (ICP) monitoring was inserted within 24 h of admission. During the first 48-72 h from admission, CGLR was measured before and 2 h after any intervention aiming to reduce ICP ("intervention"). Patients with normal ICP were also sampled at the same time points and served as the "control" group.

RESULTS

A total of 219 patients were included. In the intervention group (n = 115, 53%), ICP significantly decreased and CPP increased. After 2 h from the intervention, CGLR rose in both the intervention and control groups, although the magnitude was higher in the intervention than in the control group (20.2% vs 1.6%; p = 0.001). In a linear regression model adjusted for several confounders, therapies to manage ICP were independently associated with changes in CGLR. There was a weak inverse correlation between changes in ICP and CGRL in the intervention group.

CONCLUSIONS

In this study, CGLR significantly changed over time, regardless of the study group. However, these effects were more significant in those patients receiving interventions to reduce ICP.

Neurological and respiratory effects of lung protective ventilation in acute brain injury patients without lung injury: brain vent, a single centre randomized interventional study

INTRODUCTION

Lung protective ventilation (LPV) comprising low tidal volume (VT) and high positive end-expiratory pressure (PEEP) may compromise cerebral perfusion in acute brain injury (ABI). In patients with ABI, we investigated whether LPV is associated with increased intracranial pressure (ICP) and/or deranged cerebral autoregulation (CA), brain compensatory reserve and oxygenation.

METHODS

In a prospective, crossover study, 30 intubated ABI patients with normal ICP and no lung injury were randomly assigned to receive low VT [6 ml/kg/predicted (pbw)]/at either low (5 cmH₂O) or high PEEP (12 cmH₂O). Between each intervention, baseline ventilation (VT 9 ml/kg/pbw and PEEP 5 cmH₂O) were resumed. The safety limit for interruption of the intervention was ICP above 22 mmHg for more than 5 min. Airway and transpulmonary pressures were continuously monitored to assess respiratory mechanics. We recorded ICP by using external ventricular drainage or a parenchymal probe. CA and brain compensatory reserve were derived from ICP waveform analysis.

RESULTS

We included 27 patients (intracerebral haemorrhage, traumatic brain injury, subarachnoid haemorrhage), of whom 6 reached the safety limit, which required interruption of at least one intervention. For those without intervention interruption, the ICP change from baseline to "low VT/low PEEP" and "low VT/high PEEP" were 2.2 mmHg and 2.3 mmHg, respectively, and considered clinically non-relevant. None of the interventions affected CA or oxygenation significantly. Interrupted events were associated with high baseline ICP (p < 0.001), low brain compensatory reserve (p < 0.01) and mechanical power (p < 0.05). The transpulmonary driving pressure was 5 ± 2 cmH₂O in both interventions. Partial arterial pressure of carbon dioxide was kept in the range 34-36 mmHg by adjusting the respiratory rate, hence, changes in carbon dioxide were not associated with the increase in ICP.

CONCLUSIONS

The present study found that most patients did not experience any adverse effects of LPV, neither on ICP nor CA. However, in almost a quarter of patients, the ICP rose above the safety limit for interrupting the interventions. Baseline ICP, brain compensatory reserve, and mechanical power can predict a potentially deleterious effect of LPV and can be used to personalize ventilator settings. Trial registration NCT03278769 . Registered September 12, 2017.

Effect of gait distance during robot training on walking independence after acute brain injury

This study aimed to determine whether the distance of gait training using a hybrid assistive limb (HAL) is related to the improvement of walking independence in patients with acute brain injury. This was an exploratory, observational study. Thirty patients having hemiplegia (functional ambulation category, FAC score ≤2) with acute stroke or after brain tumor surgery were included. Patients performed 4 sessions of gait training using HAL (60 min/session), 1-3 sessions/week, combined with conventional physical therapy. The gait distance achieved in the four training sessions using HAL was measured. FAC score was measured before and after intervention. Patients were divided into groups A, B, and C, for FAC score improvements of 0, 1, and ≥2, respectively. Gait distance was compared among groups using one-way analysis of variance. Gait distance in group C was significantly longer than that ingroup A [mean (standard deviation): 2527 (1725) m vs. 608 (542) m]. This study suggested that the gait distance achieved during training using the HAL may be a clinical indicator of the effectiveness of the HAL on gait training in patients with acute brain injury.Clinical trial registration number: UMIN000012764 R000014756.

Electrolyte Imbalance and Neurologic Injury

Neurologic injury continues to be a debilitating worldwide disease with high morbidity and mortality. The systemic sequelae of a neural insult often lead to prolonged hospital stays and challenging nutritional demands that contribute to poorer prognoses. Clinical management of a given condition should prioritize preserving the homeostatic parameters disrupted by inflammatory response cascades following the primary insult. This focused review examines the reciprocal relationship between electrolyte disturbance and neurologic injury. A prolonged electrolyte imbalance can significantly impact morbidity and mortality in neurologic injuries. A detailed overview of the major electrolytes and their physiologic, iatrogenic, and therapeutic implications are included. The pathophysiology of how dysnatremias, dyskalemias, dyscalcemias, and dysmagnesemias occur and the symptoms they can induce are described. The manifestations in relation to traumatic brain injury, status epilepticus, and acute ischemic stroke are addressed. Each type of injury and the strength of its association with a disruption in either sodium, potassium, calcium, or magnesium is examined. The value of supplementation and replacement is highlighted with an emphasis on the importance of early recognition in this patient population. This review also looks at the current challenges associated with correcting imbalances in the setting of different injuries, including the relevant indications and precautions for some of the available therapeutic interventions. Based on the findings of this review, there may be a need for more distinct clinical guidelines on managing different electrolyte imbalances depending on the specified neurologic injury. Additional research and statistical data on individual associations between insult and imbalance are needed to support this potential future call for context-based protocols.

Ultrasonographic measurement of the optic nerve sheath diameter to detect intracranial hypertension: an observational study

OBJECTIVES

To evaluate the ultrasonographic measurement of optic nerve sheath diameter (ONSD) as a predictor of intracranial hypertension as compared to the invasive measurement of intracranial pressure (ICP).

DESIGN

Cross-sectional observational study.

SETTING

Intensive Care Unit (ICU) of two tertiary university hospitals in Montevideo, Uruguay.

PATIENTS

We included 56 adult patients, over 18 years of age, who required sedation, mechanical ventilation, and invasive ICP monitoring as a result of a severe acute neurologic injury (traumatic or non-traumatic) and had a Glascow Coma Score (GCS) equal to or less than 8 on admission to the ICU.

INTERVENTIONS

Ultrasonographic measurement of ONSD to detect intracranial hypertension.

MEASUREMENTS AND MAIN RESULTS

In our study, a logistic regression model was performed in which it was observed that the variable ONSD is statistically significant with a p value of 0.00803 (< 0.05). This model estimates and predicts the probability that a patient will have an ICP greater than 20 mmHg. From the analysis of the cut-off points, it is observed that a value of 5.7 mm of ONSD maximizes the sensitivity (92.9%) of the method (a greater number of individuals with ICP > 20 mmHg are correctly identified).

CONCLUSIONS

In sedated neurocritical patients, with structural Acute Brain Injury, the ONSD measurement correlates with the invasive measurement of ICP. It was observed that with ONSD values less than 5.7 mm, the probability of being in the presence of ICP above 20 mmHg is very low, while for ONSD values greater than 5.7 mm, said probability clearly increases.

Paroxysmal Sympathetic Hypertension: An Underdiagnosed Entity or a Diagnostic Difficulty?

How to cite this article: Pratyusha K, Jindal A. Paroxysmal Sympathetic Hypertension: An Underdiagnosed Entity or a Diagnostic Difficulty? Indian J Crit Care Med 2023;27(2):151.

Mechanical Ventilation in Patients with Traumatic Brain Injury: Is it so Different?

Patients with traumatic brain injury (TBI) frequently require invasive mechanical ventilation and admission to an intensive care unit. Ventilation of patients with TBI poses unique clinical challenges, and careful attention is required to ensure that the ventilatory strategy (including selection of appropriate tidal volume, plateau pressure, and positive end-expiratory pressure) does not cause significant additional injury to the brain and lungs. Selection of ventilatory targets may be guided by principles of lung protection but with careful attention to relevant intracranial effects. In patients with TBI and concomitant acute respiratory distress syndrome (ARDS), adjunctive strategies include sedation optimization, neuromuscular blockade, recruitment maneuvers, prone positioning, and extracorporeal life support. However, these approaches have been largely extrapolated from studies in patients with ARDS and without brain injury, with limited data in patients with TBI. This narrative review will summarize the existing evidence for mechanical ventilation in patients with TBI. Relevant literature in patients with ARDS will be summarized, and where available, direct data in the TBI population will be reviewed. Next, practical strategies to optimize the delivery of mechanical ventilation and determine readiness for extubation will be reviewed. Finally, future directions for research in this evolving clinical domain will be presented, with considerations for the design of studies to address relevant knowledge gaps.

Physiological Monitoring in Patients with Acute Brain Injury: A Multimodal Approach

Neurocritical care management of acute brain injury (ABI) is focused on identification, prevention, and management of secondary brain injury (SBI). Physiologic monitoring of the brain and other organ systems has a role to predict patient recovery or deterioration, guide individualized therapeutic interventions, and measure response to treatment, with the goal of improving patient outcomes. In this review, we detail how specific physiologic markers of brain injury and neuromonitoring tools are integrated and used in ABI patients to develop therapeutic approaches to prevent SBI.

The mechanical power in neurocritical care patients: is it useful?

Patients with acute brain injury have been excluded in the majority of the randomized clinical trials which evaluated a lung protective strategy in patients with acute respiratory failure. It remains unclear if low tidal volume, higher PEEP levels and recruitment maneuvers by increasing both the intracranial and intrathoracic pressure and by leading to a permissible hypercapnia could furthermore deteriorate the acute brain injury and the final outcome. Mechanical power has been associated with the outcome in ARDS patients without brain injury. Jiang et al. demonstrated in neurocritical patients that non-survivors had a higher mechanical power compared to survivors. Mechanical power was associated with an increase in intensive care mortality risk and also to an enhanced risk of hospital mortality, prolonged intensive care length of stay and fewer ventilatory free days; in addition, the mechanical power could better predict mortality compared to the Glasgow Coma Scale.

Paroxysmal Sympathetic Hyperactivity: It is Time to Use the New Diagnostic Criteria

How to cite this article: Krupanandan R. Paroxysmal Sympathetic Hyperactivity: It is Time to Use the New Diagnostic Criteria. Indian J Crit Care Med 2022;26(11):1165-1166.

Effectiveness of Training Programs for Reducing Adverse Psychological Outcomes in Parents of Children with Acquired Brain Injury: A Systematic Review and Meta-Analysis

INTRODUCTION

Parental stress following critical illness in their child has the potential to impact functional outcomes and quality of life for the child and whole family. Parent emotional functioning may also be an important clinical target to optimize child outcomes. This study assessed the effectiveness of training programs for parents aimed at reducing adverse psychological outcomes in parents of children with acute brain injury (ABI).

METHODS

We conducted searches of Embase, PubMed, Web of Science, and Cochrane Library to November 13, 2020. Randomized controlled trials (RCTs) that compared parent training programs with usual care, or an active comparator, and assessed psychological outcomes (depression, anxiety, stress) in parents of children with ABI were included. Two reviewers independently extracted data on study characteristics, participants, interventions, outcome measures, and results before and after intervention. Risk of bias was assessed using the Cochrane risk-of-bias tool.

RESULTS

Four RCTs involving 318 parents of children with ABI were eligible for review. Compared with usual care or active comparator, parent training was associated with significant reduction in parent stress (four RCTs; standardized mean difference [SMD], - 0.32 on a numerical rating scale [95% CI, - 0.60, - 0.05]; I-squared = 7.5%, p = 0.356); significant reduction in parent depression (three RCTs; SMD, - 0.43 [95% CI, - 0.72, - 0.14]; I-squared = 0.0%, p = 0.393); and significant reduction in parent anxiety (two RCTs; SMD, - 0.63 [95% CI, - 1.05, - 0.21]; I-squared = 0.0%, p = 0.629). Overall risk of bias was high for randomization process (one RCT), missing outcome data (three RCTs), measurement of the outcome (three RCTs), and selection of reported result (two RCTs). Heterogeneity between studies by country of study origin was not significant.

CONCLUSIONS

Compared with usual care or an active comparator, parent training was associated with short-term reduction in stress, depression, and anxiety in parents of children with ABI. Future clinical trials of parent interventions are needed as there may be some short-term beneficial effects.

ARDS associated acute brain injury: from the lung to the brain

A complex interrelation between lung and brain in patients with acute lung injury (ALI) has been established by experimental and clinical studies during the last decades. Although, acute brain injury represents one of the most common insufficiencies in patients with ALI and acute respiratory distress syndrome (ARDS), the underlying pathophysiology of the observed crosstalk remains poorly understood due to its complexity. Specifically, it involves numerous pathophysiological parameters such as hypoxemia, neurological adverse events of lung protective ventilation, hypotension, disruption of the BBB, and neuroinflammation in such a manner that the brain of ARDS patients-especially hippocampus-becomes very vulnerable to develop secondary lung-mediated acute brain injury. A protective ventilator strategy could reduce or even minimize further systemic release of inflammatory mediators and thus maintain brain homeostasis. On the other hand, mechanical ventilation with low tidal volumes may lead to self-inflicted lung injury, hypercapnia and subsequent cerebral vasodilatation, increased cerebral blood flow, and intracranial hypertension. Therefore, by describing the pathophysiology of ARDS-associated acute brain injury we aim to highlight and discuss the possible influence of mechanical ventilation on ALI-associated acute brain injury.

Neurologic outcome of VZV encephalitis one year after ICU admission: a multicenter cohort study

BACKGROUND

Varicella-zoster virus (VZV) is one of the main viruses responsible of acute encephalitis. However, data on the prognosis and neurologic outcome of critically ill patients with VZV encephalitis are limited. We aimed to describe the clinical features of VZV encephalitis in the ICU and to identify factors associated with a favorable neurologic outcome. We performed a multicenter cohort study of patients with VZV encephalitis admitted in 18 ICUs in France between 2000 and 2017. Factors associated with a favorable neurologic outcome, defined by a modified Rankin Score (mRS) of 0-2 1 year after ICU admission, were identified by multivariable regression analysis.

RESULTS

Fifty-five patients (29 (53%) men, median age 53 (interquartile range 36-66)) were included, of whom 43 (78%) were immunocompromised. ICU admission occurred 1 (0-3) day after the onset of neurological symptoms. Median Glasgow Coma Score at ICU admission was 12 (7-14). Cerebrospinal fluid examination displayed a median leukocyte count of 68 (13-129)/mm³, and a median protein level of 1.37 (0.77-3.67) g/L. CT scan and MRI revealed brain lesions in 30% and 66% of the cases, respectively. Invasive mechanical ventilation was implemented in 46 (84%) patients for a median duration of 13 (3-30) days. Fourteen (25%) patients died in the ICU. One year after ICU admission, 20 (36%) patients had a favorable neurologic outcome (mRS 0-2), 12 (22%) had significant disability (mRS 3-5), and 18 (33%) were deceased (lost to follow-up n = 5, 9%). On multivariable analysis, age (OR 0.92 per year, (0.88-0.97), p = 0.01), and invasive mechanical ventilation (OR 0.09 CI 95% (0.01-0.84), p = 0.03) reduced the likelihood of favorable neurologic outcome.

CONCLUSION

One in every three critically ill patients with VZV encephalitis had a favorable neurologic outcome 1 year after ICU admission. Older age and invasive mechanical ventilation were associated with a higher risk of disability and death.

Outcome of Hemorrhagic Stroke: Host Immune Response can Be a Prediction Tool!

How to cite this article: Nasa P. Outcome of Hemorrhagic Stroke: Host Immune Response can Be a Prediction Tool! Indian J Crit Care Med 2022;26(1):2-4.

Spreading depolarization induced by amygdala micro-injury prevents disruption of fear memory extinction in rats

Spreading depolarization (SD), a self-propagating wave of near-complete breakdown of the transmembrane ion gradients with water influx, regularly occurs in traumatized human brain. Here, we investigated long-term neurobehavioral consequences of injury-triggered SDs. Recently, we revealed that SD is reliably triggered by micro-injury of the amygdala, a key brain structure involved in fear processing. Using the classical Pavlovian fear conditioning paradigm, we investigated effects of the post-retrieval amygdala micro-injury and associated SD on fear memory in rats. We found that neither SD nor micro-injury alone affect fear response 24 h later but profoundly change it in subsequent extinction phase. If bilateral injury of the amygdala did not induce SD, fear extinction was severely impaired, while conditioned fear in rats with the identical amygdala injury triggering SD was successfully extinguished similarly to naïve rats. Our study provides first experimental evidence for involvement of injury-induced SD in extinction of traumatic fear memory.

Outcome of Hemorrhagic Stroke: Host Immune Response can Be a Prediction Tool!

How to cite this article: Nasa P. Outcome of Hemorrhagic Stroke: Host Immune Response can Be a Prediction Tool! Indian J Crit Care Med 2022;26(1):2-4.

Safety profile of an intracranial multimodal monitoring bolt system for neurocritical care: a single-center experience

BACKGROUND

Intracranial multimodality monitoring (iMMM) is increasingly used in acute brain-injured patients; however, safety and reliability remain major concerns to its routine implementation.

METHODS

We performed a retrospective study including all patients undergoing iMMM at a single European center between July 2016 and January 2020. Brain tissue oxygenation probe (PbtO₂), alone or in combination with a microdialysis catheter and/or an 8-contact depth EEG electrode, was inserted using a triple-lumen bolt system and targeting normal-appearing at-risk brain area on the injured side, whenever possible. Surgical complications, adverse events, and technical malfunctions, directly associated with iMMM, were collected. A blinded imaging review was performed by an independent radiologist.

RESULTS

One hundred thirteen patients with 123 iMMM insertions were included for a median monitoring time of 9 [3-14] days. Of those, 93 (76%) patients had only PbtO₂ probe insertion and 30 (24%) had also microdialysis and/or iEEG monitoring. SAH was the most frequent indication for iMMM (n = 60, 53%). At least one complication was observed in 67/123 (54%) iMMM placement, corresponding to 58/113 (51%) patients. Misplacement was observed in 16/123 (13%), resulting in a total of 6/16 (38%) malfunctioning PbtO₂ catheters. Intracranial hemorrhage was observed in 14 iMMM placements (11%), of which one required surgical drainage. Five placements were complicated by pneumocephalus and 4 with bone fragments; none of these requires additional surgery. No CNS infection related to iMMM was observed. Seven (6%) probes were accidentally dislodged and 2 probes (2%) were accidentally broken. Ten PbtO₂ probes (8%) presented a technical malfunction after a median of 9 [ranges: 2-24] days after initiation of monitoring and 4 of them were replaced.

CONCLUSIONS

In this study, a high occurrence of complications related to iMMM was observed, although most of them did not require specific interventions and did not result in malfunctioning monitoring.

Comparison of out of hospital cardiac arrest due to acute brain injury vs other causes

BACKGROUND

Acute brain injury (ABI) can cause out of hospital cardiac arrest (OHCA). The aim of this study was to compare clinical features, mortality and potential for organ donation in patients with OHCA due to ABI vs other causes.

METHODS

From January 2017 to December 2018, all adult patients presenting to ED for OHCA were considered for the study. Two physicians established the definitive cause of OHCA, according to clinical, laboratory, diagnostic imaging and autoptic findings. Clinical features in patients with OHCA due to ABI or other causes were compared.

RESULTS

280 patients were included in the analysis. ABI was the third most frequent cause of OHCA (21, 7.5%); ABIs were 8 subarachnoid hemorrhage, 8 intracerebral hemorrhage, 2 ischemic stroke, 2 traumatic spinal cord injury and 1 status epilepticus respectively. Neurological prodromes such as seizure, headache and focal neurological signs were significantly more frequent in patients with OHCA due to ABI (OR 5.34, p = 0.03; OR 12.90, p = 0.02; and OR 66.53, p < 0.01 respectively) while among non-neurological prodromes chest pain and dyspnea were significantly more frequent in patients with OHCA due to other causes (OR 14.5, p < 0.01; and OR 10.4, p = 0.02 respectively). Anisocoria was present in 19% of patients with OHCA due to ABI vs 2.7% due to other causes (OR 8.47, p < 0.01). In 90.5% of patients with ABI and in 53.1% of patients with other causes the first cardiac rhythm was non shockable (OR 8.1; p = 0.05). Multivariate logistic regression analysis revealed that older age, active smoking, post-traumatic OHCA, neurological prodromes, anisocoria at pupillary examination were independently associated with OHCA due to ABI. Patients with ABI showed a higher mortality compared with the other causes group (19 pts., 90.5% versus 167 pts., 64.5%; p = 0.015). Potential organ donors were more frequent among ABI than other causes group (10 pts., 47.6% vs 75 pts., 28.9%) however the difference did not reach the statistical significance (p = 0.07).

CONCLUSIONS

ABI is the third cause of OHCA. Neurological prodromes, absence of chest pain and dyspnea before cardiac arrest, anisocoria and initial non-shockable rhythm might suggest a neurological etiology of the cardiac arrest. Patients with OHCA due to ABI has an unfavorable outcome, however, they could be candidate to organ donation.

Prevalence and Outcome of Acute Respiratory Distress Syndrome in Traumatic Brain Injury: A Systematic Review and Meta-Analysis

OBJECTIVES

Acute respiratory distress syndrome (ARDS) in patients with traumatic brain injury (TBI) is associated with increased mortality. Information on the prevalence of ARDS and its neurological outcome after TBI is sparse. We aimed to systematically review the prevalence, risk factors, and outcome of ARDS in TBI population.

DATA SOURCES

PubMed and four other databases (Embase, Cochrane Library, Web of Science Core Collection, and Scopus) from inception to July 6, 2020.

STUDY SELECTION

Randomized controlled trials (RCTs) and observational studies in patients older than 18 years old.

DATA EXTRACTION

Two independent reviewers extracted the data. Study quality was assessed by the Cochrane Risk of Bias tool for RCTs, the Newcastle-Ottawa Scale for cohort and case-control studies. Good neurological outcome was defined as Glasgow Outcome Scale ≥ 4. Random-effects meta-analyses were conducted to estimate pooled outcome prevalence and their 95% confidence intervals (CI).

DATA SYNTHESIS

We included 20 studies (n = 2830) with median age of 44 years (interquartile range [IQR] = 35-47, 64% male) and 79% (n = 2237) suffered severe TBI. In meta-analysis, 19% patients (95% CI = 0.13-0.27, I² = 93%) had ARDS after TBI. The median time from TBI to ARDS was 3 days (IQR = 2-5). Overall survival at discharge for the TBI cohort was 70% (95% CI = 0.64-0.75; I² = 85%) and good neurological outcome at any time was achieved in 31% of TBI patients (95% CI = 0.23-0.40; I² = 88%). TBI cohort without ARDS had higher survival (67% vs. 57%, p = 0.01) and good neurological outcomes (34% vs. 23%, p = 0.02) compared to those with ARDS. We did not find any specific risk factors for developing ARDS.

CONCLUSION

In this meta-analysis, approximately one in five patients had ARDS shortly after TBI with the median time of 3 days. The presence of ARDS was associated with worse neurological outcome and mortality in TBI. Further research on prevention and intervention strategy of TBI-associated ARDS is warranted.

What Does Coma Mean? Implications for Shared Decision Making in Acute Brain Injury

BACKGROUND

Insufficient attention has been devoted to shared decision-making (SDM) in the setting of acute brain injury (ABI). Communication occupies a central role that has been highlighted in recent research on SDM with brain injured patients, with respect to "the impact of specific clinician words and expressions". In this investigation, we seek to understand lay public understandings of the term "coma."

METHODS

Qualitative analysis of lay interpretations of the term "cComa" using modified open coding of a free-text response question at the end of a survey exploring public attitudes in the context of hypothetical ABI. Respondents (n = 511) were drawn from a convenience sample using Amazon Mechanical Turk. This analysis focuses on respondents' free-text responses to the question: "When doctors say a patient is in a coma, what does that mean?"

RESULTS

We analyzed 206 unique responses in order to derive emergent lay conceptualizations of coma. The following 4 themes emerged in how respondents understood coma: (1) State descriptive. (2) Marker of injury severity. (3) As in distinction (or lack thereof) from brain death or sleep. (4) Covert consciousness. For each concept, we discuss its salient elements and offer representative quotes.

CONCLUSIONS

This study provides preliminary qualitative evidence of lay public understandings of the neurologic term "coma". These findings can have implications for surrogate/family-clinician communications. While a physician may intend "coma" to convey a technical description, a family member or surrogate may interpret it as a very different activity (e.g., prognostication, emotional signaling), setting the stage for miscommunication.

Transport study of interleukin-1 inhibitors using a human in vitro model of the blood-brain barrier

The proinflammatory cytokine Interleukin-1 (IL-1), with its two isoforms α and β, has important roles in multiple pathogenic processes in the central nervous system. The present study aimed to evaluate and compare the blood-to-brain distribution of anakinra (IL-1 receptor antagonist), bermekimab (IL-1α antagonist) and canakinumab (IL-1β antagonist).

A human in vitro model of the blood-brain barrier derived from human umbilical cord blood stem cells was used, where isolated CD34⁺ cells co-cultured with bovine pericytes were matured into polarized brain-like endothelial cells. Transport rates of the three test items were evaluated after 180 ​min incubation at concentrations 50, 250 and 1250 ​nM in a transwell system. We report herein that anakinra passes the human brain-like endothelial monolayer at a 4-7-fold higher rate than the monoclonal antibodies tested. Both antibodies had similar transport rates at all concentrations. No dose-dependent effects in transport rates were observed, nor any saturation effects at supraphysiological concentrations. The larger propensity of anakinra to pass this model of the human blood-brain barrier supports existing data and confirms that anakinra can reach the brain compartment at clinically relevant concentrations. As anakinra inhibits the actions of both IL-1α and IL-1β, it blocks all effects of IL-1 downstream signaling. The results herein further add to the growing body of evidence of the potential utility of anakinra to treat neuroinflammatory disorders.

•

Anakinra has a larger propensity to pass the in vitro BBB than monoclonal antibodies targeting the IL-1 system.

•

Implications for targeting inflammation in cerebral ischemia and neurological sequelae of autoinflammatory diseases.

•

Novel and comparative study of biologics in a human in vitro BBB model shows relevance and validity.

Impact of Head-of-Bed Posture on Brain Oxygenation in Patients with Acute Brain Injury: A Prospective Cohort Study

Background

Therapeutic head positioning plays a role in the management of patients with acute brain injury. Although intracranial pressure (ICP) is typically lower in an upright posture than in a flat position, limited data exist concerning the effect of upright positioning on brain oxygenation and circulation. We sought to determine the impact of supine (0°) and semirecumbent (15° and 30°) postures on ICP, brain oxygenation, and brain circulation.

Methods

An observational cohort study was conducted between February 2012 and September 2015. Twenty-three patients with severe acute brain injury were successively observed at head elevations of 30°, 15°, and 0°. Postural-induced changes in ICP, cerebral perfusion pressure, brain tissue oxygenation pressure, and transcranial Doppler findings were simultaneously measured during three repeated experiments: 24 h after admission to the intensive care unit (exp1), 24 h later (exp2), and 96 h later (exp3). Cerebral perfusion pressure, arterial blood gases, hemoglobin content, and body temperature remained unchanged during the three experiments.

Results

Using linear random-slope mixed models, we found that during the early phase of acute brain injury (exp1), lowering the head posture from 30° to 15°, and then to 0°, was associated with a gradual mean ICP increase of 2.6 mm Hg (1.4–3.7 mm Hg; P < 0.001); and from 30° to 0°, an increase of 7.4 mm Hg (6.3–8.6 mm Hg; P < 0.001). Furthermore, brain tissue oxygenation pressure and mean blood flow velocity improved when the head posture was lowered from 30° to 0° by 1.2 mm Hg (0.2–2.3 mm Hg) and 4.1 cm/s (0.0–8.2 cm/s), respectively (both P < 0.05).

Conclusions

Changing the positioning of stable patients with acute brain injury resulted in opposite changes of ICP versus brain oxygenation and circulation. This information supports the concept of an individualized approach to head positioning that is based on the multimodal monitoring of brain parameters.

Chronic and End-Stage Kidney Disease in the Neurological Intensive Care Unit

Patients with renal disease have increased rates of admission to the neurological intensive care unit related to overlapping risk factors for renal and cerebrovascular disease as well as unique risks associated with renal dysfunction alone. Management of acute neurological injury in these patients requires individualized attention to diagnostic and management factors as they relate to coagulopathy, disorders of immune function, encephalopathy and renal replacement modalities. Careful consideration of these brain-kidney interactions is necessary to optimize care for this special patient population and improve neurological and renal outcomes.

Preconditioning increases brain resistance against acute brain injury via neuroinflammation modulation

Acute brain injury (ABI) is a broad concept mainly comprised of sudden parenchymal brain injury. Acute brain injury outcomes are dependent not only on the severity of the primary injury, but the delayed secondary injury that subsequently follows as well. These are both taken into consideration when determining the patient's prognosis. Growing clinical and experimental evidence demonstrates that "preconditioning," a prophylactic approach in which the brain is exposed to various pre-injury stressors, can induce varying degrees of "tolerance" against the impact of the ABI by modulating neuroinflammation. In this review, we will summarize the pathophysiology of ABI, and discuss the involved mechanisms of neuroinflammation in ABI, as well as existing experimental and clinical studies demonstrating the efficacy of preconditioning methods in various types of ABI by modulating neuroinflammation.

Evaluation, Treatment, and Impact of Neurologic Injury in Adult Patients on Extracorporeal Membrane Oxygenation: a Review

Purpose

Extracorporeal membrane oxygen (ECMO) is increasingly used as an advanced form of life support for cardiac and respiratory failure. Unfortunately, in infrequent instances, circulatory and/or respiratory recovery is overshadowed by neurologic injury that can occur in patients who require ECMO. As such, knowledge of ECMO and its implications on diagnosis and treatment of neurologic injuries is indispensable for intensivists and neurospecialists.

Recent findings

The most common neurologic injuries include intracerebral hemorrhage, ischemic stroke, seizure, cerebral edema, intracranial hypertension, global cerebral hypoxia/anoxia, and brain death. These result from events prior to initiation of ECMO, failure of ECMO to provide adequate oxygen delivery, and/or complications that occur during ECMO. ECMO survivors also experience neurological and psychological sequelae similar to other survivors of critical illness.

Summary

Since many of the risk factors for neurologic injury cannot be easily mitigated, early diagnosis and intervention are crucial to limit morbidity and mortality from neurologic injury during ECMO.

Neuroprotective effect of minocycline against acute brain injury in clinical practice: A systematic review

Acute brain injury is a leading cause of morbidity and mortality worldwide. The term is inclusive of traumatic brain injury, cerebral ischemia, subarachnoid hemorrhage, and intracerebral hemorrhage. Current pharmacologic treatments have had minimal effect on improving neurological outcomes leading to a significant interest in the development neuroprotective agents. Minocycline is a second-generation tetracycline with high blood brain barrier penetrance due to its lipophilic properties. It functions across multiple molecular pathways involved in secondary-injury cascades following acute brain injury. Animal model studies suggest that minocycline might lead to improved neurologic outcomes, but few such trials exist in humans. Clinical investigations have been limited to small randomized trials in ischemic stroke patients which have not demonstrated a clear advantage in neurologic outcomes, but also have not been sufficiently powered to draw definitive conclusions. The potential neuroprotective effect of minocycline in the setting of traumatic brain injury, subarachnoid hemorrhage, and intracerebral hemorrhage have all been limited to pilot studies with phase II/III investigations pending. The authors aim to synthesize what is currently known about minocycline as a neuroprotective agent against acute brain injury in humans.