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

Multimodal neuromonitoring in the nordic countries: experiences and attitudes - a multi-institutional survey

BACKGROUND

Multimodal neuromonitoring (MMM) aids early detection of secondary brain injury in neurointensive care and facilitates research in pathophysiologic mechanisms of the injured brain. Invasive ICP monitoring has been the gold standard for decades, however additional methods exist (aMMM). It was hypothesized that local practices regarding aMMM vary considerably and that inter-and intracenter consensus is low. The survey aimed to investigate this hypothesis including the knowledge, attitudes towards, and use of aMMM in the neurointensive care setting in the Nordic countries.

METHOD

The survey was distributed amongst 54 neurosurgical trainees at a Nordic neurosurgery training course and supplemented with 16 center-appointed neuromonitoring experts representing 16 of the 19 neurosurgical centers in the Nordic countries (Norway, Sweden, Denmark, and Finland).

RESULTS

The response rate was 100% amongst the training course attendents, as well as the center-appointed experts with a total of 70 respondents. The experts covered 16/19 Nordic centers. In-center disagreement was high concerning the use of aMMM methods. In patients with traumatic brain injury, subarachnoid hemorrhage, or other acute brain injuries 50% of the appointed experts stated transcranial Doppler ultrasound (TCD) to be used in most cases in their ICU, and an additional 25% for selected cases. Most appointed experts agreed on electroencephalography (EEG) for selected cases 63%, but only 19% for most cases. Routine use of Invasive brain tissue oxygenation (PbtO2) was stated by 25-63% and cerebral microdialysis (CMD) by 19-38%. The main perceived concerns with aMMM methods were the usefulness for outcome-changing interventions (43%) and financial issues (19%). Most respondents (67%) believed automated combined analysis of aMMM to be a likely future scenario.

CONCLUSION

There was a remarkable variation in the reported use of aMMM among Nordic neurosurgical centers, indicating an extensive lack of consensus on need and utility. Surprisingly routine use of TCD was stated by 75%, presumably for routine monitoring of SAH patients, whereas CMD was mostly considered a research tool. Interestingly, junior staff and appointed experts disagreed on intended local routines, indicating that application of aMMM was more governed organically and by case than on explicit guidelines or that uniform management was not prioritized.

Blood-Based Lateral-Flow Immunoassays Dipstick Test for Damaged Mitochondrial Electron Transport Chain in Pyruvate Treated Rats with Combined Blast Exposure and Hemorrhagic Shock

Blast trauma presents a unique challenge due to its complex mechanism of injury, which impacts the brain and other vital organs through overpressure waves and internal bleeding. Severe blood loss leads to an inadequate oxygen supply and insufficient fuel delivery to cells, impairing ATP production by mitochondria-essential for cell survival. While clinical symptoms of metabolic disruption are evident soon after injury, the molecular, cellular, and systemic damage persists for days to years post-injury. Current challenges in treating traumatic brain injury (TBI) stem from (1) the lack of early blood-based biomarkers for detecting metabolic failure and mitochondrial damage and (2) the limited success of mitochondrial-targeted therapeutic strategies. Objectives: To identify blood-based mitochondrial biomarkers for evaluating the severity of brain injuries and to investigate therapeutic strategies targeting mitochondria. Methods: A preclinical rat model subjected to blast exposure, with or without hemorrhagic shock (HS), followed by resuscitation was utilized. Blood samples were obtained at baseline (T0), post-injury (T60), and at the conclusion of the experiment (T180), and analyzed using a validated dipstick assay to measure mitochondrial enzyme activity. Results: Blast and HS injuries led to a significant decrease in the activity of mitochondrial enzymes, including complex I, complex IV, and the pyruvate dehydrogenase complex (PDH), compared to baseline (p < 0.05). Concurrently, blood lactate concentrations were significantly elevated (p < 0.001). An inverse correlation was observed between mitochondrial enzyme dysfunction and blood lactate levels (p < 0.05). Treatment with sodium pyruvate post-injury restored complex I, complex IV, and PDH activity to near-baseline levels, corrected hyperlactatemia, and reduced reactive oxygen species (ROS) production by mitochondria. Conclusions: Serial monitoring of blood mitochondrial enzyme activity, such as complex I, complex IV, and PDH, may serve as a valuable tool for prognostication and guiding the use of mitochondrial-targeted therapies. Additionally, mitochondrial enzyme assays in blood samples can provide insights into the global redox status, potentially paving the way for novel therapeutic interventions in TBI.

Cerebral oxygen saturation in cirrhotic patients with gastro-intestinal bleeding, a near infrared spectroscopy study

Near Infrared Spectroscopy (NIRS) is a non-invasive optical technique allowing a continuous measurement of brain's hemoglobin (Hb) saturation in oxygen (rSO2). It is a marker of cerebral insult and rSO2 < 50% is associated with increased neurological impairment. Cirrhotic patients with gastrointestinal bleeding (GIB) often develop hepatic encephalopathy (HE). The aims of this study were: (1) to assess brain oxygenation using NIRS in cirrhotic patients with GIB, (2) to determine if brain oxygenation was correlated to Hb level, blood pressure and liver function (3) if brain oxygenation was influencing the occurrence of HE and survival. Cirrhotic patients admitted to ICU for GIB were prospectively included and compared to non-cirrhotic patients. Bilateral recording of rSO2 was started upon admission using an INVOS 5100c Cerebral Oxymeter (Covidien). Initial, minimal, average rSO2 and AUC of rSO2 < 50% (AUC50% rSO2) were extracted. Sixty-one cirrhotic and 14 non-cirrhotic patients were included. Child-Pugh score was at 9.5 ± 0.3 and MELD score was 17.8 ± 0.9. None of the NIRS parameters differed between cirrhotic and non-cirrhotic patients. Thirty-nine patients (64%) among the 61 cirrhotic and 10 (71%) among the 14 non-cirrhotic patients displayed an initial rSO2 below the 50% threshold at least on one side. NIRS parameters correlated mainly with Hb level and MELD but not with MAP or PaO2. There was no significant correlation between NIRS parameters and survival or HE upon admission, within 5 days and after discharge. Patients with GIB frequently present rSO2 below the threshold of 50%. The significance of this finding is uncertain since it does not seem clearly correlated to a poor outcome in ICU or in the follow-up.

Enhancing daily living and cognitive functions in traumatic brain injury patients through Orem's self-care theory

Introduction

This research seeks to investigate how early rehabilitation nursing, guided by Orem's self-care theory, affects cognitive function, neurological function, and daily living skills in individuals who have suffered a traumatic brain injury (TBI).

Methods

A study was conducted with 108 patients with traumatic brain injury who were hospitalized at our facility from January 2021 to March 2023. Based on their admission dates, the participants were separated into a control group (n = 56) and an observation group (n = 52). The control group received standard nursing care, while the observation group received a combination of conventional treatment and nursing interventions based on Orem's self-care model. The research assessed alterations in the ability to perform daily tasks (Activities of Daily Living, ADL), neurological health (National Institutes of Health Stroke Scale, NIHSS; Glasgow Coma Scale, GCS), and cognitive abilities (Montreal Cognitive Assessment Scale, MoCA; Mini-Mental State Examination, MMSE) in both sets of participants prior to and following 4 and 8 weeks of nursing assistance.

Results

Following the intervention, the group being observed showed notably increased ADL scores at 4 weeks (p < 0.001) and 8 weeks (p < 0.001) in comparison to the control group. At 4 weeks and 8 weeks after nursing, the observation group had significantly lower NIHSS scores compared to the control group (4 weeks after nursing, p = 0.03; 4 weeks after nursing, p < 0.001). GCS score comparison showed the similar results (4 weeks after nursing, p = 0.013; 4 weeks after nursing, p = 0.003). Moreover, the participants in the observation group had notably higher MoCA and MMSE scores in comparison with the control group 4 and 8 weeks after nursing (all p < 0.001).

Conclusion

Orem's self-care theory improves patients' cognitive, neurological, and daily living functions of TBI patients during early rehabilitation nursing. This method helps enhance the level of care given by healthcare professionals, leading to more thorough and compassionate nursing care for patients.

Noninvasive Neuromonitoring Modalities in Children Part I: Pupillometry, Near-Infrared Spectroscopy, and Transcranial Doppler Ultrasonography

BACKGROUND

Noninvasive neuromonitoring in critically ill children includes multiple modalities that all intend to improve our understanding of acute and ongoing brain injury.

METHODS

In this article, we review basic methods and devices, applications in clinical care and research, and explore potential future directions for three noninvasive neuromonitoring modalities in the pediatric intensive care unit: automated pupillometry, near-infrared spectroscopy, and transcranial Doppler ultrasonography.

RESULTS

All three technologies are noninvasive, portable, and easily repeatable to allow for serial measurements and trending of data over time. However, a paucity of high-quality data supporting the clinical utility of any of these technologies in critically ill children is currently a major limitation to their widespread application in the pediatric intensive care unit.

CONCLUSIONS

Future prospective multicenter work addressing major knowledge gaps is necessary to advance the field of pediatric noninvasive neuromonitoring.

Physiological oxygen measurements in vitro-Schrödinger's cat in 3D cell biology

After the development of 3D cell culture methods in the middle of the last century and the plethora of data generated with this culture configuration up to date, it could be shown that a three-dimensional arrangement of cells in most of the cases leads to a more physiological behavior of the generated tissue. However, a major determinant for an organotypic function, namely, the dissolved oxygen concentration in the used in vitro-system, has been neglected in most of the studies. This is due to the fact that the oxygen measurement in the beginning was simply not feasible and, if so, disturbed the measurement and/or the in vitro-system itself. This is especially true for the meanwhile more widespread use of 3D culture systems. Therefore, the tissues analyzed by these techniques can be considered as the Schrödinger's cat in 3D cell biology. In this perspective paper we will outline how the measurement and, moreover, the regulation of the dissolved oxygen concentration in vitro-3D culture systems could be established at all and how it may be possible to determine the oxygen concentration in organoid cultures and the respiratory capacity via mito stress tests, especially in spheroids in the size range of a few hundred micrometers, under physiological culture conditions, without disturbances or stress induction in the system and in a high-throughput fashion. By this, such systems will help to more efficiently translate tissue engineering approaches into new in vitro-platforms for fundamental and applied research as well as preclinical safety testing and clinical applications.

Surgical treatment of traumatic frontal hematoma: comparison of the endoscopic supraorbital approach with frontotemporal approach

Background

The objective of this study was to compare the efficacy, safety, and outcomes of the endoscopic supraorbital approach and frontotemporal approach for the treatment of traumatic frontal hematoma, with the aim of demonstrating the feasibility of the endoscopic supraorbital approach.

Methods

A total of 24 cases underwent hematoma evacuation, including 10 cases using the endoscopic supraorbital approach and 14 cases using the frontotemporal approach. Baseline demographic data, hematoma clearance rate, blood loss, postoperative complications, and 6-month outcomes were retrospectively analyzed.

Results

Both approaches effectively evacuated the hematoma, with hematoma clearance rates of 90.97 ± 10.23% in the endoscopic supraorbital group and 85.29 ± 16.15% in the frontotemporal approach group (p > 0.05). The supraorbital approach group demonstrated significantly shorter operation times compared to the frontotemporal approach group (116.50 ± 28.19 min vs. 193.29 ± 72.55 min, p < 0.05), as well as significantly less blood loss (55.00 ± 33.08 mL vs. 685.71 ± 840.20 mL, p < 0.05). There was no significant difference in the rate of postoperative complications between the two groups, and the majority of patients achieved favorable outcomes with a Glasgow Outcome Scale score of 4 or 5 in both groups.

Conclusion

Compared to the frontotemporal approach, the endoscopic supraorbital approach offers advantages such as shorter operation times, reduced blood loss, similar treatment effects, and comparable complication rates. Therefore, the endoscopic supraorbital approach may serve as a viable alternative for the treatment of traumatic frontal hematoma.

Multimodal and autoregulation monitoring in the neurointensive care unit

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

New-onset contralateral delayed extradural haematoma in an operated case of extradural haematoma: life-threatening if not diagnosed early

Head trauma is still a leading cause of mortality in neurosurgical practice. Among various post-traumatic pathologies, extradural haematoma (EDH) is an acute condition that has good neurological outcomes if intervened promptly. New contralateral delayed EDH (DEDH) in an operated case of ipsilateral EDH is a very rare entity, which if not diagnosed timely may lead to devastating outcomes, sometimes even death. We present a case of newly found contralateral DEDH with significant mass effect and midline shift in the immediate postoperative scan, in an operated case of right frontoparietal EDH, which was not found in the initial preoperative scan. A high index of suspicion is needed in cases of unilateral EDH with contralateral skull fracture along with tense dura after the evacuation of EDH, to diagnose rare but life-threatening contralateral DEDH. Routine immediate postoperative CT scan will prevent devastating complications in these kinds of patients.

Near Infrared Spectroscopy for Poor Grade Aneurysmal Subarachnoid Hemorrhage-A Concise Review

Delayed cerebral ischemia (DCI) disproportionately affects poor grade aneurysmal subarachnoid hemorrhage (aSAH) patients. An unreliable neurological exam and the lack of appropriate monitoring leads to unrecognized DCI, which in turn is associated with severe long-term deficits and higher mortality. Near Infrared Spectroscopy (NIRS) offers simple, continuous, real time, non-invasive cerebral monitoring. It provides regional cerebral oxygen saturation (c-rSO2), which reflects the balance between cerebral oxygen consumption and supply. Reports have demonstrated a good correlation with other cerebral oxygen and blood flow monitoring, and credible cerebrovascular reactivity indices were also derived from NIRS signals. Multiple critical c-rSO2 values have been reported in aSAH patients, based on various thresholds, duration, variation from baseline or cerebrovascular reactivity indices. Some were associated with vasospasm, some with DCI and others with clinical outcomes. However, the poor grade aSAH population has not been specifically studied and no randomized clinical trial has been published. The available literature does not support a specific NIRS-based intervention threshold to guide diagnostic or treatment in aSAH patients. We review herein the fundamental basic concepts behind NIRS technology, relationship of c-rSO2 to other brain monitoring values and their potential clinical interpretation. We follow with a critical evaluation of the use of NIRS in the aSAH population, more specifically its ability to diagnose vasospasm, to predict DCI and its association to outcome. In summary, NIRS might offer significant potential for poor grade aSAH in the future. However, current evidence does not support its use in clinical decision-making, and proper technology evaluation is required.

Paroxysmal Sympathetic Hyperactivity in Moderate-to-Severe Traumatic Brain Injury and the Role of Beta-Blockers: A Scoping Review

INTRODUCTION

Most cases of paroxysmal sympathetic hyperactivity (PSH) result from traumatic brain injury (TBI). Little is known about its pathophysiology and treatment, and several neuroprotective drugs are used including beta-blockers. The aim of our study is to collate existing evidence of the role of beta-blockers in the treatment of PSH.

METHODS

We searched MEDLINE, ResearchGate, and Google Scholar, for keywords related to PSH and the role of beta-blockers in moderate-to-severe TBI on September 23, 2020. Two authors blindly screened the articles found with Rayyan. Both resolved their conflicts by mutual consent. If no solution was found, a third author was consulted. Simple descriptive data analysis was performed and the results were presented both in a narrative and tabular form.

RESULTS

Of the 19 items found, 10 met the criteria for inclusion. 50% were systematic reviews without meta-analysis, 40% were observational studies, and 10% were experimental studies. Propranolol was the main beta-blocker found in 80% of the studies and was the only molecule used in the treatment of paroxysmal sympathetic hyperactivity in 40% of the included studies. Only two studies evaluated and showed a significant association between beta-blockers and mortality rate (5.1% vs. 10.8%; P=0.03), (3% vs. 15%; P=0.002), respectively.

CONCLUSION

Propranolol is the beta-blocker that has been shown to be effective in reducing the length of stay and mortality rate in moderate-severe traumatic brain injury patients with PSH. However, further studies are needed to precisely define the terms and conditions of its use.

A Review of Monitoring Methods for Cerebral Blood Oxygen Saturation

In recent years, cerebral blood oxygen saturation has become a key indicator during the perioperative period. Cerebral blood oxygen saturation monitoring is conducive to the early diagnosis and treatment of cerebral ischemia and hypoxia. The present study discusses the three most extensively used clinical methods for cerebral blood oxygen saturation monitoring from different aspects: working principles, relevant parameters, current situations of research, commonly used equipment, and relative advantages of different methods. Furthermore, through comprehensive comparisons of the methods, we find that near-infrared spectroscopy (NIRS) technology has significant potentials and broad applications prospects in terms of cerebral oxygen saturation monitoring. Despite the current NIRS technology, the only bedside non-invasive cerebral oxygen saturation monitoring technology, still has many defects, it is more in line with the future development trend in the field of medical and health, and will become the main method gradually.

Usefulness of Cerebral Oximetry in TBI by NIRS

Measurement of cerebral oximetry by near-infrared spectroscopy provides continuous and non-invasive information about the oxygen saturation of haemoglobin in the central nervous system. This is especially important in the case of patients with traumatic brain injuries. Monitoring of cerebral oximetry in these patients could allow for the diagnosis of inadequate cerebral oxygenation caused by disturbances in cerebral blood flow. It could enable identification of episodes of hypoxia and cerebral ischemia. Continuous bedside measurement could facilitate the rapid diagnosis of intracranial bleeding or cerebrovascular autoregulation disorders and accelerate the implementation of treatment. However, it should be remembered that the method of monitoring cerebral oximetry by means of near-infrared spectroscopy also has its numerous limitations, resulting mainly from its physical properties. This paper summarizes the usefulness of monitoring cerebral oximetry by near-infrared spectroscopy in patients with traumatic brain injury, taking into account the advantages and the disadvantages of this technique.