Neuromonitoring in neonatal intensive care units-an important need towards individualized neuroprotective care.

Neuromonitoring has been widely accepted as an important part in neonatal care. Amplitude-integrated EEG (aEEG) and near-infrared spectroscopy (NIRS) are often mentioned in this context, though being only a part of the fully array of methods and examinations that could be considered neuromonitoring. Within the broad array of medical conditions that could be encountered in a neonatal patient, it is important to be aware of the indications for neuromonitoring and especially which neuromonitoring technique to use best for the individual condition. aEEG is now a widely accepted neuromonitor in neonatology with its value in hypoxic events and seizures only rarely questioned. Other methods like NIRS still have to prove themselves in the future. The SafeBoosC-III trial showed that it still remains difficult for some of these methods to prove their value for the improvement of outcome. Bute future developments such as multimodal neuromonitoring with data integration and artificial intelligence analysis could improve the value of these methods.

The Impact of Invasive Brain Oxygen Pressure Guided Therapy on the Outcome of Patients with Traumatic Brain Injury: A Systematic Review and Meta-Analysis.

Traumatic brain injury (TBI) is a major public health burden, causing death and disability worldwide. Intracranial hypertension and brain hypoxia are the main mechanisms of secondary brain injury. As such, management strategies guided by intracranial pressure (ICP) and brain oxygen (PbtO2) monitoring could improve the prognosis of these patients. Our objective was to summarize the current evidence regarding the impact of PbtO2-guided therapy on the outcome of patients with TBI. We performed a systematic search of PubMed, Scopus, and the Cochrane library databases, following the protocol registered in PROSPERO. Only studies comparing PbtO2/ICP-guided therapy with ICP-guided therapy were selected. Primary outcome was neurological outcome at 3 and 6 months assessed by using the Glasgow Outcome Scale; secondary outcomes included hospital and long-term mortality, burden of intracranial hypertension, and brain tissue hypoxia. Out of 6254 retrieved studies, 15 studies (n = 37,245 patients, of who 2184 received PbtO2-guided therapy) were included in the final analysis. When compared with ICP-guided therapy, the use of combined PbO2/ICP-guided therapy was associated with a higher probability of favorable neurological outcome (odds ratio 2.21 [95% confidence interval 1.72-2.84]) and of hospital survival (odds ratio 1.15 [95% confidence interval 1.04-1.28]). The heterogeneity (I2) of the studies in each analysis was below 40%. However, the quality of evidence was overall low to moderate. In this meta-analysis, PbtO2-guided therapy was associated with reduced mortality and more favorable neurological outcome in patients with TBI. The low-quality evidence underlines the need for the results from ongoing phase III randomized trials.

Intracerebral Iron Accumulation may be Associated with Secondary Brain Injury in Patients with Poor Grade Subarachnoid Hemorrhage.

BACKGROUND: The amount of intracranial blood is a strong predictor of poor outcome after subarachnoid hemorrhage (SAH). Here, we aimed to measure iron concentrations in the cerebral white matter, using the cerebral microdialysis (CMD) technique, and to associate iron levels with the local metabolic profile, complications, and functional outcome. METHODS: For the observational cohort study, 36 patients with consecutive poor grade SAH (Hunt & Hess grade of 4 or 5, Glasgow Coma Scale Score ≤ 8) undergoing multimodal neuromonitoring were analyzed for brain metabolic changes, including CMD iron levels quantified by graphite furnace atomic absorption spectrometry. The study time encompassed 14 days after admission. Statistical analysis was performed using generalized estimating equations. RESULTS: Patients were admitted in a poor clinical grade (n = 26, 72%) or deteriorated within 24 h (n = 10, 28%). The median blood volume in the subarachnoid space was high (SAH sum score = 26, interquartile range 20-28). Initial CMD iron was 44 µg/L (25-65 µg/L), which significantly decreased to a level of 25 µg/L (14-30 µg/L) at day 4 and then constantly increased over the remaining neuromonitoring days (p < 0.01). A higher intraventricular hemorrhage sum score (≥ 5) was associated with higher CMD iron levels (Wald-statistic = 4.1, df = 1, p = 0.04) but not with the hemorrhage load in the subarachnoid space (p = 0.8). In patients developing vasospasm, the CMD iron load was higher, compared with patients without vasospasm (Wald-statistic = 4.1, degree of freedom = 1, p = 0.04), which was not true for delayed cerebral infarction (p = 0.4). Higher iron concentrations in the brain extracellular fluid (34 µg/L, 36-56 µg/L vs. 23 µg/L, 15-37 µg/L) were associated with mitochondrial dysfunction (CMD lactate to pyruvate ratio > 30 and CMD-pyruvate > 70 µM/L, p < 0.001). Brain extracellular iron load was not associated with functional outcome after 3 months (p > 0.5). CONCLUSIONS: This study suggests that iron accumulates in the cerebral white matter in patients with poor grade SAH. These findings may support trials aiming to scavenger brain extracellular iron based on the hypothesis that iron-mediated neurotoxicity may contribute to acute and secondary brain injury following SAH.

Mismatch between Tissue Partial Oxygen Pressure and Near-Infrared Spectroscopy Neuromonitoring of Tissue Respiration in Acute Brain Trauma: The Rationale for Implementing a Multimodal Monitoring Strategy.

The brain tissue partial oxygen pressure (PbtO2) and near-infrared spectroscopy (NIRS) neuromonitoring are frequently compared in the management of acute moderate and severe traumatic brain injury patients; however, the relationship between their respective output parameters flows from the complex pathogenesis of tissue respiration after brain trauma. NIRS neuromonitoring overcomes certain limitations related to the heterogeneity of the pathology across the brain that cannot be adequately addressed by local-sample invasive neuromonitoring (e.g., PbtO2 neuromonitoring, microdialysis), and it allows clinicians to assess parameters that cannot otherwise be scanned. The anatomical co-registration of an NIRS signal with axial imaging (e.g., computerized tomography scan) enhances the optical signal, which can be changed by the anatomy of the lesions and the significance of the radiological assessment. These arguments led us to conclude that rather than aiming to substitute PbtO2 with tissue saturation, multiple types of NIRS should be included via multimodal systemic- and neuro-monitoring, whose values then are incorporated into biosignatures linked to patient status and prognosis. Discussion on the abnormalities in tissue respiration due to brain trauma and how they affect the PbtO2 and NIRS neuromonitoring is given.

Neuroglucopenia and Metabolic Distress in Two Patients with Viral Meningoencephalitis: A Microdialysis Study.

INTRODUCTION: Viral encephalitis is an emerging disease requiring intensive care management in severe cases. Underlying pathophysiologic mechanisms are incompletely understood and may be elucidated using invasive multimodal neuromonitoring techniques in humans. METHODS: Two otherwise healthy patients were admitted to our neurological intensive care unit with altered level of consciousness necessitating mechanical ventilation. Brain imaging and laboratory workup suggested viral encephalitis in both patients. Invasive neuromonitoring was initiated when head computed tomography revealed generalized brain edema, including monitoring of intracranial pressure, brain metabolism (cerebral microdialysis; CMD), brain tissue oxygen tension (in one patient), and cerebral blood flow (in one patient). RESULTS: Brain metabolism revealed episodes of severe neuroglucopenia (brain glucose <0.7 mM/l) in both patients, which were not attributable to decreased cerebral perfusion or hypoglycemia. CMD-glucose levels changed depending on variations in insulin therapy, nutrition, and systemic glucose administration. The metabolic profile, moreover, showed a pattern of non-ischemic metabolic distress suggestive for mitochondrial dysfunction. Both patients had a prolonged but favorable clinical course and improved to a modified Rankin Scale Score of 1 and 0 three months later. CONCLUSION: Invasive multimodal neuromonitoring is feasible in poor-grade patients with viral meningoencephalitis and may help understand pathophysiologic mechanisms associated with secondary brain injury. The detection of neuroglucopenia and mitochondrial dysfunction may serve as treatment targets in the future.

[Specialized neurological neurosurgical intensive care medicine]. / Spezialisierte neurologische neurochirurgische Intensivmedizin.

In Germany dedicated neurological-neurosurgical critical care (NCC) is the fastest growing specialty and one of the five big disciplines integrated within the German critical care society (Deutsche Interdisziplinäre Vereinigung für Intensiv- und Notfallmedizin; DIVI). High-quality investigations based on resilient evidence have underlined the need for technical advances, timely optimization of therapeutic procedures, and multidisciplinary team-work to treat those critically ill patients. This evolution has repeatedly raised questions, whether NCC-units should be run independently or better be incorporated within multidisciplinary critical care units, whether treatment variations exist that impact clinical outcome, and whether nowadays NCC-units can operate cost-efficiently? Stroke is the most frequent disease entity treated on NCC-units, one of the most common causes of death in Germany leading to a great socio-economic burden due to long-term disabled patients. The main aim of NCC employs surveillance of structural and functional integrity of the central nervous system as well as the avoidance of secondary brain damage. However, clinical evaluation of these severely injured commonly sedated and mechanically ventilated patients is challenging and highlights the importance of neuromonitoring to detect secondary damaging mechanisms. This multimodal strategy not only requires medical expertise but also enforces the need for specialized teams consisting of qualified nurses, technical assistants and medical therapists. The present article reviews most recent data and tries to answer the aforementioned questions.

Cerebral Taurine Levels are Associated with Brain Edema and Delayed Cerebral Infarction in Patients with Aneurysmal Subarachnoid Hemorrhage.

BACKGROUND: Cerebral edema and delayed cerebral infarction (DCI) are common complications after aneurysmal subarachnoid hemorrhage (aSAH) and associated with poor functional outcome. Experimental data suggest that the amino acid taurine is released into the brain extracellular space secondary to cytotoxic edema and brain tissue hypoxia, and therefore may serve as a biomarker for secondary brain injury after aSAH. On the other hand, neuroprotective mechanisms of taurine treatment have been described in the experimental setting. METHODS: We analyzed cerebral taurine levels using high-performance liquid chromatography in the brain extracellular fluid of 25 consecutive aSAH patients with multimodal neuromonitoring including cerebral microdialysis (CMD). Patient characteristics and clinical course were prospectively recorded. Associations with CMD-taurine levels were analyzed using generalized estimating equations with an autoregressive process to handle repeated observations within subjects. RESULTS: CMD-taurine levels were highest in the first days after aSAH (11.2 ± 3.2 µM/l) and significantly decreased over time (p < 0.001). Patients with brain edema on admission or during hospitalization (N = 20; 80 %) and patients developing DCI (N = 5; 20 %) had higher brain extracellular taurine levels compared to those without (Wald = 7.3, df = 1, p < 0.01; Wald = 10.1, df = 1, p = 0.001, respectively) even after adjusting for disease severity and CMD-probe location. There was no correlation between parenteral taurine supplementation and brain extracellular taurine (p = 0.6). Moreover, a significant correlation with brain extracellular glutamate (r = 0.82, p < 0.001), lactate (r = 0.56, p < 0.02), pyruvate (r = 0.39, p < 0.01), potassium (r = 0.37, p = 0.01), and lactate-to-pyruvate ratio (r = 0.24, p = 0.02) was found. CONCLUSIONS: Significantly higher CMD-taurine levels were found in patients with brain edema or DCI after aneurysmal subarachnoid hemorrhage. Its value as a potential biomarker deserves further investigation.

From Pansinusitis to Cerebritis Due to Eikenella corrodens.

Meningitis is a rare but possible complication of sinusitis. We present a case of a 21-year-old woman with a history of fever, headache and nasal obstruction who presented at the emergency department with psychomotor agitation. Orotracheal intubation and invasive mechanical ventilation were given to protect airway. Blood analysis showed leukocytosis and elevated C-reactive protein. Cerebral and maxillofacial computed tomography (CT) demonstrated pansinusitis with gas foci more prominent in the left frontal sinus with an area of ​​bone rarefaction on the posterior wall with possible communication with the cranial cavity. Lumbar puncture was performed. Empirical antibiotic and corticosteroid therapy were started. Neurosurgery (NC) and Ear Nose and Throat (ENT) surgeons declined indication for urgent surgery and she was admitted at General ICU. On the fourth day of hospitalization, a brain magnetic resonance imaging (CE-MRI) was performed, revealing subdural empyema and cerebritis adjacent to the frontal sinus. She was transferred to the reference neurosurgical center for surgical interventions and was admitted post-operatively at the Neurocritical Care Unit (NCCU). Reevaluation MRI showed residual anterior frontal empyema and absence of focus control in peri-nasal sinusitis, requiring a new ENT surgery. A Streptococcus spp was isolated from the blood, Eikenella corrodens from the pus collected from the sinuses, and the CSF was sterile. The patient completed 21 days of antibiotic therapy. She was extubated on the 19th day, with Broca's aphasia and right hemiparesis, and on the 23rd day transferred to the ENT Service and later to the Rehabilitation Service. We present a case of atypical central nervous system (CNS) infection by a rare agent, highlighting the importance of vigilance, focus control, and neurocritical care. In a severe and complex manifestation like this, the management typically involves medical and surgical interventions. Subdural empyema should be treated as a neurosurgical emergency due to the potential rapid deterioration in patient's neurological condition, attributed to secondary damage. In this case, brain multimodal monitoring, was very helpful in acute phase management. Neurocritical care teams should be involved early in patients with this presentation of CNS infection to provide optimal management, reducing complications and secondary brain lesions therefore improving patient outcomes.

Intracranial Hypotension Syndrome: The Importance of Neurointensive Care.

Surgical procedures involving the spine can result in various complications, including vascular, nerve root and dura mater injury, surgical wound infection, and hematoma formation. Unintentional durotomy is a frequent complication of these procedures (up to 17%). Two clinical cases are reported in which the occurrence of epileptiform activity in the form of generalized tonic-clonic seizures after instrumentation of the dorsal and lumbar spine raised suspicion of cerebrospinal fluid (CSF) fistula. In both cases, the diagnostic suspicion and early approach allowed for the adoption of a timely medical and surgical plan, with the aim of reducing the volume of lost CSF as well as the potential neurological dysfunction resulting from this surgical complication.

Multi-Mechanistic Approaches to the Treatment of Traumatic Brain Injury: A Review.

Traumatic brain injury (TBI) is a leading cause of death and disability worldwide. Despite extensive research efforts, the majority of trialed monotherapies to date have failed to demonstrate significant benefit. It has been suggested that this is due to the complex pathophysiology of TBI, which may possibly be addressed by a combination of therapeutic interventions. In this article, we have reviewed combinations of different pharmacologic treatments, combinations of non-pharmacologic interventions, and combined pharmacologic and non-pharmacologic interventions for TBI. Both preclinical and clinical studies have been included. While promising results have been found in animal models, clinical trials of combination therapies have not yet shown clear benefit. This may possibly be due to their application without consideration of the evolving pathophysiology of TBI. Improvements of this paradigm may come from novel interventions guided by multimodal neuromonitoring and multimodal imaging techniques, as well as the application of multi-targeted non-pharmacologic and endogenous therapies. There also needs to be a greater representation of female subjects in preclinical and clinical studies.

Neuromonitoring detects brain injury in patients receiving extracorporeal membrane oxygenation support.

OBJECTIVE: There is limited evidence on standardized protocols for optimal neurological monitoring methods in patients receiving extracorporeal membrane oxygenation (ECMO). We previously introduced protocolized noninvasive multimodal neuromonitoring using serial neurological examinations, electroencephalography, transcranial Doppler ultrasound, and somatosensory evoked potentials. The purpose of this study was to examine if standardized neuromonitoring is associated with detection of acute brain injury (ABI) and improved patient outcomes. METHODS: A retrospective analysis of ECMO patients who received neurocritical care consultation was performed and outcomes were reviewed. The cohort was stratified according to those who did not receive standardized neuromonitoring (era 1: 2016-2017) and those who received standardized neuromonitoring (era 2: 2017-2020). Multivariable logistic regression was used to evaluate the association between standardized neuromonitoring and ABI. RESULTS: A total of 215 patients (mean age, 54 years; 60% male) underwent ECMO (71% venoarterial-ECMO) in our institution, 70 in era 1 and 145 in era 2. The proportion of patients diagnosed with ABI were 23% in era 1 and 33% in era 2 (P = .12). In multivariable logistic regression, standardized neuromonitoring (odds ratio, 2.24; 95% CI, 1.12-4.48; P = .02) and pre-ECMO cardiac arrest (odds ratio, 2.17; 95% CI, 1.14-4.14; P = .02) were independently associated with ABI. There was a greater proportion of patients with good neurological outcomes when discharged alive in era 2 (54% vs 30%; P = .04). CONCLUSIONS: Standardized neuromonitoring was associated with increased ABIs in ECMO patients. Although neuromonitoring does not prevent ABI from occurring, it might prevent worsening with timely interventions (eg, anticoagulation management, optimizing oxygen delivery and blood pressure), leading to improved neurological outcomes at discharge.

Multimodal Neuromonitoring and Neurocritical Care in Swine to Enhance Translational Relevance in Brain Trauma Research.

Neurocritical care significantly impacts outcomes after moderate-to-severe acquired brain injury, but it is rarely applied in preclinical studies. We created a comprehensive neurointensive care unit (neuroICU) for use in swine to account for the influence of neurocritical care, collect clinically relevant monitoring data, and create a paradigm that is capable of validating therapeutics/diagnostics in the unique neurocritical care space. Our multidisciplinary team of neuroscientists, neurointensivists, and veterinarians adapted/optimized the clinical neuroICU (e.g., multimodal neuromonitoring) and critical care pathways (e.g., managing cerebral perfusion pressure with sedation, ventilation, and hypertonic saline) for use in swine. Moreover, this neurocritical care paradigm enabled the first demonstration of an extended preclinical study period for moderate-to-severe traumatic brain injury with coma beyond 8 h. There are many similarities with humans that make swine an ideal model species for brain injury studies, including a large brain mass, gyrencephalic cortex, high white matter volume, and topography of basal cisterns, amongst other critical factors. Here we describe the neurocritical care techniques we developed and the medical management of swine following subarachnoid hemorrhage and traumatic brain injury with coma. Incorporating neurocritical care in swine studies will reduce the translational gap for therapeutics and diagnostics specifically tailored for moderate-to-severe acquired brain injury.

Traumatic Brain Injury Update.

Traumatic brain injury is a devastating, life-changing event in most cases. After the primary brain insult, it is helpful to use evidence-based monitoring techniques to guide implementation of essential interventions to minimize secondary injury and thereby improve patient outcomes. An update on multimodal neuromonitoring is provided in this narrative review, with discussion of tools and techniques currently used in the treatment of patients with brain injury. Neuroprotective treatments, from the well-studied targeted temperature management to new potential therapeutics under investigation, such as glyburide, also are presented.

Severe hypotension with loss of motor evoked potentials during cervical surgery prompting immediate cardiovascular resuscitation.

BACKGROUND: Intraoperative neuromonitoring (IONM) is a well-established adjunct to spinal surgery to ensure safety of the neural elements.IONM has extremely high sensitivity and specificity for impending neurologic damage. In very rare instances, hypoperfusion of the cord may lead to a loss of IONM modalities that may be reversed if blood pressure issues responsible for the drop out of potentials are immediately addressed. CASE DESCRIPTION: The authors describe a case in which IONM documented hypoperfusion of the cord intraoperatively due to hypotension. Recognition of this problem and reversal of the hypotension resulted in normalization of postoperative function. CONCLUSION: The use of IONM allowed for quick recognition of an impending neurological insult during spinal deformity surgery. Prompt response to signaling changes allowed for the correction of hypotension and favorable neurologic outcome.

The effect of the volemic and cardiac status on brain oxygenation in patients with subarachnoid hemorrhage: a bi-center cohort study.

BACKGROUND: Fluid management in patients after subarachnoid hemorrhage (SAH) aims at the optimization of cerebral blood flow and brain oxygenation. In this study, we investigated the effects of hemodynamic management on brain oxygenation by integrating advanced hemodynamic and invasive neuromonitoring. METHODS: This observational cohort bi-center study included data of consecutive poor-grade SAH patients who underwent pulse contour cardiac output (PiCCO) monitoring and invasive neuromonitoring. Fluid management was guided by the transpulmonary thermodilution system and aimed at euvolemia (cardiac index, CI ≥ 3.0 L/min/m2; global end-diastolic index, GEDI 680-800 mL/m2; stroke volume variation, SVV < 10%). Patients were managed using a brain tissue oxygenation (PbtO2) targeted protocol to prevent brain tissue hypoxia (BTH, PbtO2 < 20 mmHg). To assess the association between CI and PbtO2 and the effect of fluid challenges on CI and PbtO2, we used generalized estimating equations to account for repeated measurements. RESULTS: Among a total of 60 included patients (median age 56 [IQRs 47-65] years), BTH occurred in 23% of  the monitoring time during the first 10 days since admission. Overall, mean CI was within normal ranges (ranging from 3.1 ± 1.3 on day 0 to 4.1 ± 1.1 L/min/m2 on day 4). Higher CI levels were associated with higher PbtO2 levels (Wald = 14.2; p < 0.001). Neither daily fluid input nor fluid balance was associated with absolute PbtO2 levels (p = 0.94 and p = 0.85, respectively) or the occurrence of BTH (p = 0.68 and p = 0.71, respectively). PbtO2 levels were not significantly different in preload dependent patients compared to episodes of euvolemia. PbtO2 increased as a response to fluid boluses only if BTH was present at baseline (from 13 ± 6 to 16 ± 11 mmHg, OR = 13.3 [95% CI 2.6-67.4], p = 0.002), but not when all boluses were considered (p = 0.154). CONCLUSIONS: In this study a moderate association between increased cardiac output and brain oxygenation was observed. Fluid challenges may improve PbtO2 only in the presence of baseline BTH. Individualized hemodynamic management requires advanced cardiac and brain monitoring in critically ill SAH patients.

Cerebral Autoregulation Is Impaired During Deep Hypothermia-A Porcine Multimodal Neuromonitoring Study.

Effects of brain temperature modulation on cerebral hemodynamics are unclear. We aimed at investigating changes of dynamic cerebral autoregulation (AR) indices during induction of deep hypothermia (HT) in a porcine model mimicking the clinical scenario of accidental HT. Thirteen pigs were surface-cooled to a core temperature of 28°C. High-frequency monitoring included brain temperature, mean arterial blood pressure (MAP), intracranial pressure (ICP), brain tissue oxygen tension (PbtO2), and regional oxygen saturation (rSO2) assessed by near-infrared spectroscopy to calculate AR-indices (pressure reactivity index [PRx], oxygen reactivity index [ORx], and cerebral oximetry index [COx]). Brain temperature decreased from 39.3°C ± 0.8°C to 28.8°C ± 1.0°C within a median 160 minutes (interquartile range 146-191 minutes), reflecting a rapid induction of deep HT (-4°C/h). MAP and cerebral perfusion pressure (CPP) remained stable until a brain temperature of 35°C (69 ± 8 mmHg, 53 ± 7 mmHg) and decreased to 58 ± 17 mmHg and 40 ± 17 mmHg at 28°C (p = 0.031 and p = 0.015). Despite the decrease in MAP and CPP, brain oxygenation increased (PbtO2: +5 mmHg, p = 0.037; rSO2: +7.3%, p = 0.029). There was no change in ICP during HT induction. Baseline AR-indices reflected normal cerebral AR and did not change until a brain temperature of 34°C (ORx), 33°C (PRx), and 30°C (COx). At lower temperature, AR-indices increased (PRx: p < 0.001, ORx: p = 0.02, COx: p = 0.03), reflecting impaired cerebral AR. Cerebrovascular reactivity is impaired at lower brain temperature levels. Although these temperatures are usually not targeted in clinical routine, this should be kept in mind when treating patients with accidental deep HT.

Intraoperative Neurophysiologic Monitoring for Lumbar Intradural Schwannomas: Does It Affect Clinical Outcome?

OBJECTIVE: Intraoperative multimodal neuromonitoring (IONM) is considered valuable for the early detection and prevention of any neurologic compromise during spine surgery. It has also become the standard of care at many institutions to improve the surgical outcome and be a safety net for both clinical and medicolegal concerns. METHODS: Our experience and outcomes in 46 consecutive cases of lumbar intradural schwannoma resection were reviewed with respect to clinical outcomes and patient safety, before and after the integration of IONM into our clinical practice. RESULTS: Total surgical resection of schwannomas in the lumbar spine led to improved health-related quality of life for patients. The standard technique for microsurgical resection of schwannomas requires identifying and resecting the fiber of origin for the schwannoma, guided with triggered electromyographic monitoring. However, whether this changed the surgical strategy, because spinal roots that gave rise to the schwannoma were frequently found to be nonfunctional during surgery, remains unclear. In our series of 46 patients, we did not recognize any additional motor deficit after the surgery, regardless of the use of IONM. CONCLUSIONS: Despite our analysis proving no difference in clinical outcomes with or without the use of IONM during surgical excision of lumbar schwannomas, we still prefer using IONM as a standard approach. It adds to the confidence and ease of mind of the surgeon during resection and also provides valuable data in cases of medicolegal disputes. However, it comes with an increased cost and lengthened surgical procedure.

Adjustable and Rigid Fixation of Brain Tissue Oxygenation Probe (Licox) in Neurosurgery: From Bench to Bedside.

Multimodal neuromonitoring has become a fundamental part of management for many neurosurgical disorders such as subarachnoid hemorrhage and severe traumatic brain injury. Brain tissue oxygen tension monitoring requires insertion of a probe into the brain parenchyma through a single multiple lumen bolt, or in a subcutaneously tunneled fashion. As those patients often require early magnetic resonance imaging, typically using bolts is disadvantageous due to massive metal artifact. Similarly, subcutaneous tunneling is often problematic as suture fixation can loosen over time. We hereby report a new method of fixation of the Licox brain tissue oxygenation probe with 1 or 2 3-way taps that are attached to a standard plastic cannula, resulting in a stable connection with no need for further direct sutures around the probe and above all with no metal artifacts, which negates magnetic resonance imaging. The extended fixation system was first tested with cardiopulmonary resuscitation in a brain injured porcine model. It was thereafter adopted in our daily clinical practice.

The importance of bilateral monitoring of cerebral oxygenation (NIRS): Clinical case of asymmetry during cardiopulmonary bypass secondary to previous cerebral infarction. / Importancia de la monitorización bilateral de la oxigenación cerebral: caso clínico de asimetría durante el bypass cardiopulmonar secundaria a infarto cerebral previo.

Cerebral oximetry based on near infrared spectroscopy (NIRS) technology is used to determine cerebral tissue oxygenation. We hereby present the clinical case of a 12-month old child with right hemiparesis secondary to prior left middle cerebral artery stroke 8 months ago. The child underwent surgical enlargement of the right ventricular outflow tract (RVOT) with cardiopulmonary bypass. During cardiopulmonary bypass, asymmetric NIRS results were detected between both hemispheres. The utilization of multimodal neuromonitoring (NIRS-BIS) allowed acting on both perfusion pressure and anesthetic depth to balance out the supply and demand of cerebral oxygen consumption. No new neurological sequelae were observed postoperatively. We consider bilateral NIRS monitoring necessary in order to detect asymmetries between cerebral hemispheres. Although asymmetries were not present at baseline, they can arise intraoperatively and its monitoring thus allows the detection and treatment of cerebral ischemia-hypoxia in the healthy hemisphere, which if undetected and untreated would lead to additional neurological damage.