New trends in neuromonitoring patients with aneurysmal subarachnoid haemorrhage

Neurointensive care of patients with subarachnoid haemorrhage is based on the theory that clinical outcome is the consequence of the primary haemorrhage and a number of secondary insults in the acute post haemorrhage period. Several neuromonitoring techniques have been introduced or accomplished into clinical practice in the last decade with the purpose of monitoring different but related aspects of brain physiology, such as cerebral blood flow (CBF), pressure within the cranial cavity, metabolism, and oxygenation. The aim of these techniques is to obtain information that can improve knowledge on brain pathophysiology, and especially to detect secondary insults which may cause permanent neurological damage if undetected and untreated in "real time", at the time when they can still be managed. These techniques include intracranial pressure (ICP) measurements, jugular venous oxygen saturation, near-infrared spectroscopy, brain tissue monitoring, and transcranial Doppler. The available devices are limited because they measure a part of complex process indirectly. Expense, technical difficulties, invasiveness, limited spatial or temporal resolution and the lack of sensitivity add to the limitation of any individual monitor. These problems have been partially addressed by the combination of several monitors known as multimodality monitoring. In this review, we describe the most common neuromonitoring methods in patients with subarachnoidal hemorrhage that can assess nervous system function, cerebral haemodynamics and cerebral oxygenation.

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Cerebral oxygenation monitoring in patients during and after cardiac arrest -- a narrative review of current methods and evidence

10.22514/sv.2021.141 ◽

2021 ◽

Keyword(s):

Cardiac Arrest ◽

Near Infrared ◽

Cerebral Oxygenation ◽

The Body ◽

Narrative Review ◽

Oxygen Balance ◽

Monitoring Methods ◽

Venous Oxygen Saturation ◽

Oxygenation Monitoring ◽

The Impact

Hypoxic-ischemic brain injury (HIBI) is a leading cause of mortality in post-cardiac arrest (post-CA) patients who successfully survive the initial cardiopulmonary resuscitation (CPR) but later die in the Intensive Care Unit (ICU). Therefore, a key priority of post-resuscitation ICU care is to prevent and limit the impact of HIBI by optimizing the balance between cerebral oxygen delivery and demand. Traditionally, an optimal systemic oxygen balance is considered to ensure the brain’s oxygen balance. However, the validity of this assumption is uncertain, as the brain constitutes only 2%of the body mass while accounting for approximately 20% of basal oxygen consumption at rest. Hence, there is a real need to monitor cerebral oxygenation realistically. Several imaging and bedside monitoring methods are available for cerebral oxygenation monitoring in post-CA patients. Unfortunately, each of them has its limitations. Imaging methods require transporting a critically ill unstable patient to the scanner. Moreover, they provide an assessment of the oxygenation state only at a particular moment, while brain oxygenation is dynamic. Bedside methods, specifically near-infrared spectroscopy (NIRS), brain tissue oxygen tension (PbtO2), and jugular venous oxygen saturation monitoring (SjvO2), have not often been used in studies involving post-CA patients. Hence there is ambiguity regarding clear recommendations for using these bedside monitors. Presently, the most promising option seems to be using the NIRS as an indicator of effective CPR. We present a narrative review focusing on bedside methods and discuss the evidence for their use in adult patients after cardiac arrest.

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Wearable brain imaging with multimodal physiological monitoring

Journal of Applied Physiology ◽

10.1152/japplphysiol.00297.2017 ◽

2018 ◽

Vol 124 (3) ◽

pp. 564-572 ◽

Cited By ~ 13

Author(s):

Gary E. Strangman ◽

Vladimir Ivkovic ◽

Quan Zhang

Keyword(s):

Human Performance ◽

Near Infrared ◽

Cerebral Oxygenation ◽

Tissue Imaging ◽

Central Component ◽

Physiological Monitoring ◽

Self Monitoring ◽

Brain Physiology ◽

And Performance ◽

Clinical Conditions

The brain is a central component of cognitive and physical human performance. Measures, including functional brain activation, cerebral perfusion, cerebral oxygenation, evoked electrical responses, and resting hemodynamic and electrical activity are all related to, or can predict, health status or performance decrements. However, measuring brain physiology typically requires large, stationary machines that are not suitable for mobile or self-monitoring. Moreover, when individuals are ambulatory, systemic physiological fluctuations—e.g., in heart rate, blood pressure, skin perfusion, and more—can interfere with noninvasive brain measurements. In efforts to address the physiological monitoring and performance assessment needs for astronauts during spaceflight, we have developed easy-to-use, wearable prototypes, such as NINscan, for near-infrared scanning, which can collect synchronized multimodal physiology data, including hemodynamic deep-tissue imaging (including brain and muscles), electroencephalography, electrocardiography, electromyography, electrooculography, accelerometry, gyroscopy, pressure, respiration, and temperature measurements. Given their self-contained and portable nature, these devices can be deployed in a much broader range of settings—including austere environments—thereby, enabling a wider range of novel medical and research physiology applications. We review these, including high-altitude assessments, self-deployable multimodal e.g., (polysomnographic) recordings in remote or low-resource environments, fluid shifts in variable-gravity, or spaceflight analog environments, intracranial brain motion during high-impact sports, and long-duration monitoring for clinical symptom-capture in various clinical conditions. In addition to further enhancing sensitivity and miniaturization, advanced computational algorithms could help support real-time feedback and alerts regarding performance and health.

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Neuromonitoring with near-infrared spectroscopy (NIRS) in aneurysmal subarachnoid haemorrhage: a systematic review protocol

BMJ Open ◽

10.1136/bmjopen-2020-043300 ◽

2020 ◽

Vol 10 (11) ◽

pp. e043300

Author(s):

Mohamed Reda Bensaidane ◽

Alexis F Turgeon ◽

François Lauzier ◽

Shane W English ◽

Guillaume Leblanc ◽

...

Keyword(s):

Infrared Spectroscopy ◽

Subarachnoid Haemorrhage ◽

Diagnostic Accuracy ◽

Near Infrared Spectroscopy ◽

Near Infrared ◽

Cerebral Oximetry ◽

Evaluation Methodology ◽

Controlled Trials ◽

Aneurysmal Subarachnoid Haemorrhage ◽

Cochrane Central Register

IntroductionAneurysmal subarachnoid haemorrhage (aSAH) is a devastating disease associated with high mortality and morbidity. The main threat to patients is delayed cerebral ischaemia (DCI). Near-infrared spectroscopy (NIRS) is a recent technology allowing continuous, non-invasive cerebral oximetry that could permit timely detection of impending DCI and appropriate intervention to improve outcomes. However, the ability of regional oxygen saturation to detect DCI, its association to the outcome, or benefits of any interventions based on NIRS data, are lacking. Our aims are to evaluate NIRS technology both as a therapeutic tool to improve outcomes in aSAH patients and as a diagnostic tool for DCI.Methods and analysisMEDLINE, EMBASE, Web of Science, the Cochrane Central Register of Controlled Trials and the Cochrane Database of Systematic Reviews will be searched from their inception and without language restriction. Our search strategy will cover the themes of subarachnoid haemorrhage and cerebral oximetry, without limitations regarding studied outcomes. We will identify all observational and interventional human studies of adult patients hospitalised after aSAH that were monitored using NIRS. Functional outcome measures, including the modified Rankin Scale, the Glasgow Outcome Scale and the Barthel Index, will constitute the primary outcome. The Cochrane Risk of Bias tool will be used for randomised controlled trials, the ROBINS-I tool to assess non-randomised studies of interventions and the Newcastle-Ottawa Scale for cohort or case–control studies. The Quality Assessment of Diagnostic Accuracy Studies-2 will be applied to studies evaluating NIRS diagnostic accuracy for DCI. We will evaluate the quality of the evidence of the effect based on the Grading of Recommendations Assessment, Development and Evaluation methodology.Ethics and disseminationDissemination will proceed through submission for journal publication, trial registry completion and abstract presentation. Ethics approval is not required.PROSPERO registration numberCRD42020077522.

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Effects of hypothermia, hypoxia and hypercapnia on brain oxygenation and haemodynamic parameters during simulated avalanche burial - a porcine study

Journal of Applied Physiology ◽

10.1152/japplphysiol.00498.2020 ◽

2020 ◽

Author(s):

Giacomo Strapazzon ◽

Gabriel Putzer ◽

Tomas Dal Cappello ◽

Marika Falla ◽

Patrick Braun ◽

...

Keyword(s):

Repeated Measures ◽

Cerebral Oxygenation ◽

Haemodynamic Instability ◽

Brain Oxygenation ◽

Brain Physiology ◽

Haemodynamic Parameters ◽

Venous Oxygen Saturation ◽

Cerebral Desaturation ◽

Triple H ◽

Cerebral Venous Oxygen Saturation

Avalanche patients who are completely buried but still able to breathe are exposed to hypothermia, hypoxia and hypercapnia (triple H syndrome). Little is known about how these pathologic changes affect brain physiology. Study aim was to investigate the effect of hypothermia, hypoxia and hypercapnia on brain oxygenation and systemic and cerebral haemodynamics. Anaesthetised pigs were surface-cooled to 28°C. Inspiratory oxygen (FiO2) was reduced to 17% and hypercapnia induced. Haemodynamic parameters and blood gas values were monitored. Cerebral measurements included cerebral perfusion pressure (CPP), brain tissue oxygen tension (PbtO2), cerebral venous oxygen saturation (ScvO2) and regional cerebral oxygenation saturation (rSO2). Tests were interrupted when haemodynamic instability occurred or 60 min after hypercapnia induction. ANOVA for repeated measures was used to compare values across phases. There was no clinically relevant reduction in cerebral oxygenation (PbtO2, ScvO2, rSO2) during hypothermia and initial FiO2 reduction. Hypercapnia was associated with an increase in pulmonary resistance followed by a decrease in cardiac output and CPP, resulting in haemodynamic instability and cerebral desaturation (decrease in PbtO2, ScvO2, rSO2). Hypercapnia may be the main cause of cardiovascular instability, which seems to be the major trigger for a decrease in cerebral oxygenation in triple H syndrome despite severe hypothermia.

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