Monitoring Of Brain Oxygenation Research Articles

180 The Impact of Brain Tissue Oxygen Monitoring With Intracranial Pressure Monitoring on Patients With Severe TBI: A National Trauma Bank Data Analysis

INTRODUCTION: While numerous studies have demonstrated the importance of ICP monitoring in improving the mortality rate for severe traumatic brain injuries (TBI), the benefits of brain oxygenation monitoring (PbO2) in combination with ICP monitoring are still currently under investigation as part of the BOOST III trial. METHODS: Patients with severe TBI based on the Glascow Coma Scale were identified using National Trauma Bank data from 2019-2021. Patients who died in the ED, had ED disposition inconsistent with severe TBI, or were transferred to another hospital were excluded. Summary statistics, t-tests, chi-square tests, non-parametric tests, multivariate logistic models, and log-log regression models were used to evaluate and model the data. RESULTS: 13,139 patients with severe TBI who underwent ICP monitoring were identified, with 709 (5%) undergoing PbO2 monitoring. Patients with PbO2 monitors had longer ICU length of stay (17.3 days vs. 14.3 days p < .05) and a longer duration of ventilation (14.5 days vs. 12 days p < .05). Additionally, patients with PbO2 monitors experienced increased rates of deep vein thrombosis and pulmonary embolism (OR 1.57 95% CI; 1.22-2.01). There was no significant difference in mortality rate with PbO2 monitoring after controlling for severity (4.5% vs. 4%, p = 0.07). CONCLUSIONS: PbO2 monitoring was associated with longer ICU length of stay and days ventilated, consistent with prior studies. Patients with PbO2 monitoring experienced higher rates of deep vein thrombosis and pulmonary embolism. Different from previous studies, our results indicate PbO2 monitoring does not impact mortality outcomes. Data about functional outcomes are not yet available. Further studies are needed to address this discrepancy; the ongoing BOOST III trial may provide a better understanding on the proper use of PbO2 monitoring.

Monitoring of Perioperative Microcirculation Dysfunction by Near-Infrared Spectroscopy for Neurological Deterioration and Prognosis of Aneurysmal Subarachnoid Hemorrhage: An Observational, Longitudinal Cohort Study.

No evidence has established a direct causal relationship between early microcirculation disturbance after aneurysmal subarachnoid hemorrhage (aSAH) and neurological function prognosis, which is the key pathophysiological mechanism of early brain injury (EBI) in patients with aSAH. A total of 252 patients with aSAH were enrolled in the Neurosurgical Intensive Care Unit of Southwest Hospital between January 2020 and December 2022 and divided into the no neurological deterioration, early neurological deterioration, and delayed neurological deterioration groups. Indicators of microcirculation disorders in EBI included regional cerebral oxygen saturation (rSO2) measured by near-infrared spectroscopy (NIRS), brain oxygen monitoring, and other clinical parameters for evaluating neurological function and determining the prognosis of patients with aSAH. Our data suggest that the rSO2 is generally lower in patients who develop neurological deterioration than in those who do not and that there is at least one time point in the population of patients who develop neurological deterioration where left and right cerebral hemisphere differences can be significantly monitored by NIRS. An unordered multiple-classification logistic regression model was constructed, and the results revealed that multiple factors were effective predictors of early neurological deterioration: reoperation, history of brain surgery, World Federation of Neurosurgical Societies (WFNS) grade4-5, Fisher grade3-4, SAFIRE grade 3-5, abnormal serum sodium and potassium levels, and reduced rSO2 during the perioperative period. However, for delayed neurological deterioration in patients with aSAH, only a history of brain surgery and perioperative RBC count were predictive indicators. The rSO2 concentration in patients with neurological deterioration is generally lower than that in patients without neurological deterioration, and at least one time point in the population with neurological deterioration can be significantly monitored via NIRS. However, further studies are needed to determine the role of microcirculation and other predictive factors in the neurocritical management of EBI after aSAH, as these factors can reduce the incidence of adverse outcomes and mortality during hospitalization.

Brain oxygenation monitoring

Brain oxygenation monitoring

Streamlined quantitative BOLD for detecting visual stimulus-induced changes in oxygen extraction fraction in healthy participants: toward clinical application in human glioma

ObjectiveMonitoring brain oxygenation is critical in brain tumors, as low oxygenation influences tumor growth, pathological angiogenesis, and treatment resistance. This study examined the ability of the streamlined quantitative (sq)BOLD MRI technique to detect oxygenation changes in healthy individuals, as well as its potential application in a clinical setting.MethodsWe used the asymmetric spin echo (ASE) technique with FLAIR preparation, along with model-based Bayesian inference to quantify the reversible transverse relaxation rate (R2') and oxygen extraction fraction (OEF) across the brain at baseline and during visual stimulation in eight healthy participants at 3T; and two patients with glioma at rest only.ResultsComparing sqBOLD-derived parameters between baseline and visual stimulation revealed a decrease in OEF from 0.56 ± 0.09 at baseline to 0.54 ± 0.07 at the activated state (p = 0.04, paired t test) within a functional localizer-defined volume of interest, and a decline in R2' from 6.5 ± 1.3s−1 at baseline to 6.2 ± 1.4s−1 at the activated state (p = 0.006, paired t test) in the visual cortex.ConclusionThe sqBOLD technique is sensitive enough to detect and quantify changes in oxygenation in the healthy brain and shows potential for integration into clinical settings to provide valuable information on oxygenation in glioma.

Quantitative Electroencephalographic Changes Associated With Brain Tissue Hypoxia After Pediatric Traumatic Brain Injury: A Retrospective Exploratory Analysis.

Brain tissue hypoxia is associated with poor outcomes after pediatric traumatic brain injury. Although invasive brain oxygenation (PbtO 2 ) monitoring is available, noninvasive methods assessing correlates to brain tissue hypoxia are needed. We investigated EEG characteristics associated with brain tissue hypoxia. We performed a retrospective analysis of 19 pediatric traumatic brain injury patients undergoing multimodality neuromonitoring that included PbtO 2 and quantitative electroencephalography(QEEG). Quantitative electroencephalography characteristics were analyzed over electrodes adjacent to PbtO 2 monitoring and over the entire scalp, and included power in alpha and beta frequencies and the alpha-delta power ratio. To investigate relationships of PbtO 2 to quantitative electroencephalography features using time series data, we fit linear mixed effects models with a random intercept for each subject and one fixed effect, and an auto-regressive order of 1 to model between-subject variation and correlation for within-subject observations. Least squares (LS) means were used to investigate for fixed effects of quantitative electroencephalography features to changes in PbtO 2 across thresholds of 10, 15, 20, and 25 mm Hg. Within the region of PbtO 2 monitoring, changes in PbtO 2 < 10 mm Hg were associated with reductions of alpha-delta power ratio (LS mean difference -0.01, 95% confidence interval (CI) [-0.02, -0.00], p = 0.0362). Changes in PbtO 2 < 25 mm Hg were associated with increases in alpha power (LS mean difference 0.04, 95% CI [0.01, 0.07], p = 0.0222). Alpha-delta power ratio changes are observed across a PbtO 2 threshold of 10 mm Hg within regions of PbtO 2 monitoring, which may reflect an EEG signature of brain tissue hypoxia after pediatric traumatic brain injury.

Comparison of peripheral blood saturation with brain oxygenation in patients undergoing thoracic surgery.

Near-infrared spectroscopy (NIRS) is a non-invasive method of regional tissue oxygenation measurement. Intraoperative use of NIRS to monitor brain oxygenation (BO) during surgery might be beneficial to identify cerebral desaturations. To compare peripheral blood saturation (SpO2) with BO measurements and evaluate the utility of BO in thoracic surgery. We took BO and SpO2 measurements in a group of 100 patients undergoing standard thoracic surgery. Measurements were made every 15 minutes. The Mann-Whitney U test was used to compare study groups. Spearman's rank correlation coefficient was used to determine correlation between studied parameters. We found a negative correlation between patients' age and BO at the beginning of surgery. Operations lasted between 30 and 200 minutes. We found a positive correlation between BO and SpO2 between 15 and 90 minutes of surgery. Subsequently, BO remained at a low level while SpO2 returned to baseline values. Higher minimum SpO2 values were noted in patients undergoing left-sided procedures. Cerebral oxygenation does not return to baseline values until the end of the surgery as opposed to the SpO2. Furthermore, both SpO2 and BO correlate negatively with the overall duration of thoracic surgery. In addition, after 90 minutes of surgery, SpO2 stopped reflecting brain oxygenation.

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 6months 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.

Role of Cerebral Oximetry in Extracorporeal Membrane Oxygenation

AbstractCerebral oximetry, which is based on near-infrared spectroscopy (NIRS) technology, is an optical technique that allows for noninvasive and continuous monitoring of brain oxygenation by determining cerebral tissue blood oxygen saturation. Many research and observational studies were performed with neonates using various types of NIRS/cerebral oximetry monitors. However, no food and drug administration (FDA) approved-cerebral oximeter is available for neonates. Successful validation of cerebral oximetry for the FDA has been done in human adult volunteer studies under protocols in which jugular bulb and arterial blood samples were obtained under different levels of fractional inspired oxygen levels.

Association Analysis of the Cerebral Fractional Tissue Oxygen Extraction (cFTOE) and the Cerebral Oxygen Saturation (crSaO2) with Perinatal Factors in Preterm Neonates: A Single Centre Study.

(1) Background: Near-infrared spectroscopy (NIRS) is a non-invasive, easily performed method of monitoring brain oxygenation. The regional cerebral oxygen saturation (crSaO2) and the cerebral fractional tissue oxygen extraction (cFTOE) evaluated by NIRS provide more accurate information on brain oxygenation than the blood oxygen saturation. We investigated the effect of perinatal factors on cerebral oxygenation of preterm newborns. (2) Methods: We conducted a longitudinal study with 48 preterm newborns <34 weeks of gestation who underwent NIRS registration during the first 72 h of life. crSaO2 was measured and cFTOE was calculated foreach patient. (3) Results: One-way ANOVA showed no significant main effect of IVH severity on crSaO2 and cFTOE (p > 0.05); there was a tendency toward statistical significance concerning the difference between the means of crSaO2 (p = 0.083) and cFTOE (p = 0.098). Patients with intraventricular haemorrhage (IVH) had a lower mean of crSaO2 and a higher mean of cFTOE (59.67 ± 10.37% vs. 64.92 ± 10.16% for crSaO2; 0.37 ± 0.11 vs. 0.32 ± 0.11 for cFTOE) compared to those with no IVH. Significantly lower values of crSaO2 and higher values of cFTOE were found in neonates receiving inotropic treatment (p < 0.0001). Episodes of apnoea also proved to influence the cerebral oxygen saturation of the study group (p = 0.0026). No significant association between the maternal hypertension treatment and the cerebral oxygenation of preterms was found. (4) Conclusions: This study showed a decreased cerebral oxygen saturation of preterms with IVH, inotrope support and apnoea episodes.

Time-domain NIRS system based on supercontinuum light source and multi-wavelength detection: validation for tissue oxygenation studies.

We present and validate a multi-wavelength time-domain near-infrared spectroscopy (TD-NIRS) system that avoids switching wavelengths and instead exploits the full capability of a supercontinuum light source by emitting and acquiring signals for the whole chosen range of wavelengths. The system was designed for muscle and brain oxygenation monitoring in a clinical environment. A pulsed supercontinuum laser emits broadband light and each of two detection modules acquires the distributions of times of flight of photons (DTOFs) for 16 spectral channels (used width 12.5 nm / channel), providing a total of 32 DTOFs at up to 3 Hz. Two emitting fibers and two detection fiber bundles allow simultaneous measurements at two positions on the tissue or at two source-detector separations. Three established protocols (BIP, MEDPHOT, and nEUROPt) were used to quantitatively assess the system’s performance, including linearity, coupling, accuracy, and depth sensitivity. Measurements were performed on 32 homogeneous phantoms and two inhomogeneous phantoms (solid and liquid). Furthermore, measurements on two blood-lipid phantoms with a varied amount of blood and Intralipid provide the strongest validation for accurate tissue oximetry. The retrieved hemoglobin concentrations and oxygen saturation match well with the reference values that were obtained using a commercially available NIRS system (OxiplexTS) and a blood gas analyzer (ABL90 FLEX), except a discrepancy occurs for the lowest amount of Intralipid. In-vivo measurements on the forearm of three healthy volunteers during arterial (250 mmHg) and venous (60 mmHg) cuff occlusions provide an example of tissue monitoring during the expected hemodynamic changes that follow previously well-described physiologies. All results, including quantitative parameters, can be compared to other systems that report similar tests. Overall, the presented TD-NIRS system has an exemplary performance evaluated with state-of-the-art performance assessment methods.

Cardiac Output and Cerebral Oxygenation in Term Neonates during Neonatal Transition.

The immediate transition from foetus to neonate includes substantial changes, especially concerning the cardiovascular system. Furthermore, the brain is one of the most vulnerable organs to hypoxia during this period. According to current guidelines for postnatal stabilization, the recommended parameters for monitoring are heart rate (HR) and arterial oxygen saturation (SpO2). Recently, there is a growing interest in advanced monitoring of the cardio-circulatory system and the brain to get further objective information about the neonate’s condition during the immediate postnatal transition after birth. The aim of the present study was to combine cardiac output (CO) and brain oxygenation monitoring in term neonates after caesarean section in order to analyse the potential influence of CO on cerebral oxygenation during neonatal transition. This was a monocentric, prospective, observational study. For non-invasive cardiac output measurements, the electrical velocimetry (EV) method (Aesculon Monitor, Osypka Medical, CA, USA) was used. The pulse oximeter probe for SpO2 and HR measurements was placed on the right hand or wrist. The cerebral tissue oxygen index (cTOI) was measured using a NIRO-200NX monitor with the near-infrared spectroscopy (NIRS) transducer on the right frontoparietal head. Monitoring started at minute 1 and was continued until minute 15 after birth. At minutes 5, 10, and 15 after birth, mean CO was calculated from six 10 s periods (with beat-to-beat analysis). During the study period, 99 term neonates were enrolled. Data from neonates with uncomplicated transitions were analysed. CO showed a tendency to decrease until minute 10. During the complete observational period, there was no significant correlation between CO and cTOI. The present study was the first to investigate a possible correlation between CO and cerebral oxygenation in term infants during the immediate neonatal transition. In term infants with uncomplicated neonatal transition after caesarean section, CO did not correlate with cerebral oxygenation.

Neuroprotection of the Perinatal Brain by Early Information of Cerebral Oxygenation and Perfusion Patterns.

Abnormal patterns of cerebral perfusion/oxygenation are associated with neuronal damage. In preterm neonates, hypoxemia, hypo-/hypercapnia and lack of cerebral autoregulation are related to peri-intraventricular hemorrhages and white matter injury. Reperfusion damage after perinatal hypoxic ischemia in term neonates seems related with cerebral hyperoxygenation. Since biological tissue is transparent for near infrared (NIR) light, NIR-spectroscopy (NIRS) is a noninvasive bedside tool to monitor brain oxygenation and perfusion. This review focuses on early assessment and guiding abnormal cerebral oxygenation/perfusion patterns to possibly reduce brain injury. In term infants, early patterns of brain oxygenation helps to decide whether or not therapy (hypothermia) and add-on therapies should be considered. Further NIRS-related technical advances such as the use of (functional) NIRS allowing simultaneous estimation and integrating of heart rate, respiration rate and monitoring cerebral autoregulation will be discussed.

The clinical effects of cerebral near-infrared spectroscopy monitoring (NIRS) versus no monitoring: a protocol for a systematic review with meta-analysis and trial sequential analysis

BackgroundMultiple clinical conditions are associated with cerebral hypoxia/ischaemia and thereby an increased risk of hypoxic-ischaemic brain injury. Cerebral near-infrared spectroscopy monitoring (NIRS) is a tool to monitor brain oxygenation and perfusion, and the clinical uptake of NIRS has expanded over recent years. Specifically, NIRS is used in the neonatal, paediatric, and adult perioperative and intensive care settings. However, the available literature suggests that clinical benefits and harms of cerebral NIRS monitoring are uncertain. As rates of clinically significant hypoxic-ischaemic brain injuries are typically low, it is difficult for randomised clinical trials to capture a sufficiently large number of events to evaluate the clinical effect of cerebral NIRS monitoring, when focusing on specific clinical settings. The aim of this systematic review will be to evaluate the benefits and harms of clinical care with access to cerebral NIRS monitoring versus clinical care without cerebral NIRS monitoring in children and adults across all clinical settings.MethodsWe will conduct a systematic review with meta-analysis and trial sequential analysis. We will only include randomised clinical trials. The primary outcomes are all-cause mortality, moderate or severe persistent cognitive or neurological deficit, and proportion of participants with one or more serious adverse events. We will search CENTRAL, EMBASE, MEDLINE, and the Science Citation Index Expanded from their inception and onwards. Two reviewers will independently screen all citations, full-text articles, and extract data. The risk of bias will be appraised using the Cochrane risk of bias tool version 2.0. If feasible, we will conduct both random-effects meta-analysis and fixed-effect meta-analysis of outcome data. Additional analysis will be conducted to explore the potential sources of heterogeneity (e.g. risk of bias, clinical setting).DiscussionAs we include trials across multiple clinical settings, there is an increased probability of reaching a sufficient information size. However, heterogeneity between the included trials may impair our ability to interpret results to specific clinical settings. In this situation, we may have to depend on subgroup analyses with inherent increased risks of type I and II errors.Systematic review registrationPROSPERO CRD42020202986. This systematic review protocol has been submitted for registration in the International Prospective Register of Systematic Reviews (PROSPERO) (http://www.crd.york.ac.uk/prospero) on the 12th of October 2020 and published on the 12th of November 2020 (registration ID CRD42020202986).

Application of continuous monitoring of intracranial pressure and brain oxygen partial pressure in the treatment of patients with severe craniocerebral injury

To investigate the effects of continuous monitoring intracranial pressure (ICP) and brain oxygen partial pressure (PbtO2) on the prognosis of patients with severe craniocerebral injury. A prospective randomized controlled trial was conducted. Seventy patients with severe craniocerebral injury with a Glasgow coma score (GCS) 4-8 admitted to the neurosurgical intensive care unit (NICU) of the People's Hospital of Inner Mongolia Autonomous Region from January 2017 to May 2020 were enrolled, and they were divided into ICP monitoring group and ICP+PbtO2 monitoring group by random number table. Patients in ICP monitoring group received ICP monitoring and were given traditional treatment of controlling ICP and cerebral perfusion pressure (CPP), the therapeutic target was ICP < 20 mmHg (1 mmHg = 0.133 kPa) and CPP > 60 mmHg. Patients in ICP+PbtO2 monitoring group were given ICP and PbtO2 monitoring at the same time, and oxygen flow was adjusted on the basis of controlling ICP and CPP to maintain the PbtO2 > 20 mmHg, and the therapeutic target of ICP and CPP was the same as the ICP monitoring group. ICP and PbtO2 values were recorded during monitoring in the two groups, the results of CPP, GCS and arterial blood gas analysis were recorded, and the prognosis at 3 months and 6 months after injury was compared by Glasgow outcome scale (GOS) score between the two groups. GOS score > 3 was considered as good prognosis. Kaplan-Meier survival curve was drawn, and the 3-month and 6-month cumulative survival rates of the two groups were analyzed. Linear regression analysis was used to further evaluate the relationship between PbtO2 and GOS score. Finally, a total of 70 patients with severe craniocerebral injury were enrolled in the analysis, 34 patients received ICP combined with PbtO2 monitoring and guided therapy, and 36 patients received ICP monitoring alone. The average ICP of ICP+PbtO2 monitoring group was significantly lower than that of ICP monitoring group (mmHg: 13.4±3.2 vs. 18.2±8.3, P < 0.01). Although the CPP in both groups was great than 60 mmHg, the average CPP of ICP+PbtO2 monitoring group was significantly higher than that of ICP monitoring group (mmHg: 82.1±10.5 vs. 74.5±11.6, P < 0.01). No significant difference was found in average GCS score or arterial partial pressure of carbon dioxide (PaCO2) between the ICP+PbtO2 monitoring group and ICP monitoring group [GCS score: 5.3±2.3 vs. 5.2±2.2, PaCO2 (mmHg): 33.5±4.8 vs. 32.6±5.2, both P > 0.05]. The average arterial partial pressure of oxygen (PaO2) of ICP+PbtO2 monitoring group was obviously higher than that of ICP monitoring group (mmHg: 228.4±93.6 vs. 167.3±81.2, P < 0.01). Compared with the ICP monitoring group, the good outcome rates of 3 months and 6 months after injury in the ICP+PbtO2 monitoring group were significantly higher (3 months: 67.6% vs. 38.9%, 6 months: 70.6% vs. 41.7%, both P < 0.05). Kaplan-Meier survival curve showed that the 3-month and 6-month cumulative survival rates of ICP+PbtO2 monitoring group were significantly higher than those of ICP monitoring group (3 months: 85.3% vs. 61.1%, Log-Rank test: χ2 = 5.171, P = 0.023; 6 months: 79.4% vs. 55.6%, Log-Rank test: χ2 = 4.511, P = 0.034). Linear regression analysis showed that PbtO2 was significantly correlated with GOS score at 3 months and 6 months after injury in patients with severe craniocerebral injury (r values were 0.951 and 0.933, both P < 0.01). PbtO2 compared with ICP monitoring guiding therapy is valuable in improving the prognosis of patients with severe craniocerebral injury. It can improve the prognosis at 3-6 months after injury.

A Clinical Test for a Newly Developed Direct Brain Cooling System for the Injured Brain and Pattern of Cortical Brainwaves in Cooling, Noncooling, and Dead Brain.

To ensure the direct delivery of therapeutic hypothermia at a selected constant temperature to the injured brain, a newly innovated direct brain cooling system was constructed. The practicality, effectiveness, and safety of this system were clinically tested in our initial series of 14 patients with severe head injuries. The patients were randomized into two groups: direct brain cooling at 32°C and the control group. All of them received intracranial pressure (ICP), focal brain oxygenation, brain temperature, and direct cortical brainwave monitoring. The direct brain cooling group did better in the Extended Glasgow Outcome Scale at the time of discharge and at 6 months after trauma. This could be owing to a trend in the monitored parameters; reduction in ICP, increment in cerebral perfusion pressure, optimal brain redox regulation, near-normal brain temperature, and lessening of epileptic-like brainwave activities are likely the reasons for better outcomes in the cooling group. Finally, this study depicts interesting cortical brainwaves during a transition time from being alive to dead. It is believed that the demonstrated cortical brainwaves follow the principles of quantum physics.

Modern experience in conducting cerebral oximetry in neonatology: review

Annotation. Near-infrared spectroscopy (NIRS), non-invasive monitoring of tissue oxygenation in many organs, has potentially high diagnostic and prognostic value in critically ill patients. Aim – to analyze modern scientific data on cerebral oximetry by near infrared spectroscopy in neonatal practice. A selective review of literature science data on Internet databases: Pub Med, UpToDate, Medscape EU and Pediatrics was carried out in retrospect. It has been established that understanding neonatal brain oxygenation may be of great clinical importance, since most neonatal pathology is associated with the brain. Vital monitoring provides important information about the infant's health, but does not offer direct information about oxygenation and brain perfusion. Monitoring brain oxygenation with NIRS, at least during the vulnerable transition period during the first 3 days after birth, provides the clinician with additional important information. It can guide clinical management to prevent brain injury and prevent unnecessary treatment, and can provide important information about the infant’s prognosis. Thus, NIRS is a promising non-invasive technology that provides continuous monitoring of neonatal oxygenation parameters. Significant limitations of the method are the difficulties in the clinical interpretation of regional oxygenation indices, the lack of large-scale studies to determine the normative values of regional oxygenation in newborns and to identify reliable prognostic indicators in violation of regional blood circulation. It is reasonable to expect the results of further research.

Non-Invasive Techniques for Multimodal Monitoring in Traumatic Brain Injury: Systematic Review and Meta-Analysis.

Monitoring brain oxygenation and intracranial pressure non-invasively and continuously is of paramount importance in traumatic brain injury (TBI). The primary motivation of this study was to identify and provide robust evidence of the most effective techniques for the non-invasive multimodal monitoring for traumatic brain injury. Two reviewers independently searched PubMed, Embase, Scopus, the Cochrane Library, and the Web of Science between January 15, 2010, and January 22, 2020. Cohort studies assessing correlation or accuracy of non-invasive techniques for intracranial pressure (ICP) and/or brain oxygenation monitoring in TBI patients were included. The Newcastle-Ottawa Scale was used to assess the methodological quality of the studies. PROSPERO registration ID is CRD42020164739. Eight out of the 12 studies selected focused on the non-invasive measurement of ICP. Near-Infrared spectroscopy was the main technology for brain oxygenation, whereas ultrasound-based techniques were also used for ICP monitoring. PbtO2 monitoring through near-infrared spectroscopy showed low correlation and limited accuracy in detecting hypoxic events. A meta-analysis on non-invasive ICP monitoring revealed a strong pooled correlation coefficient of 0.725 (95 % confidence interval [CI]: 0.450-0.874; I2 91.31%) between transcranial Doppler and the gold standard ICP monitoring. The current meta-analysis has shown that the two most prominent and widely used technologies for non-invasive monitoring in TBI are near-infrared spectroscopy and transcranial Doppler. Both techniques could be considered for the future development of a single non-invasive and continuous multimodal monitoring device for TBI.

Assessment of a Non Invasive Brain Oximeter in Volunteers Undergoing Acute Hypoxia.

IntroductionResearch in traumatic brain injury suggests better patient outcomes when invasive oxygen monitoring is used to detect and correct episodes of brain hypoxia. Invasive brain oxygen monitoring is, however, not routinely used due to the risks, costs and technical challengers. We are developing a non-invasive brain oximeter to address these limitations. The monitor uses the principles of pulse oximetry to record a brain photoplethysmographic waveform and oxygen saturations. We undertook a study in volunteers to assess the new monitor.Patients and MethodsWe compared the temporal changes in the brain and skin oxygen saturations in six volunteers undergoing progressive hypoxia to reach arterial saturations of 70%. This approach provides a method to discriminate potential contamination of the brain signal by skin oxygen levels, as the responses in brain and skin oxygen saturations are distinct due to the auto-regulation of cerebral blood flow to compensate for hypoxia. Conventional pulse oximetry was used to assess skin oxygen levels. Blood was also collected from the internal jugular vein and correlated with the brain oximeter oxygen levels.ResultsAt baseline, a photoplethysmographic waveform consistent with that expected from the brain was obtained in five subjects. The signal was adequate to assess oxygen saturations in three subjects. During hypoxia, the brain's oximeter oxygen saturation fell to 74%, while skin saturation fell to 50% (P<0.0001). The brain photoplethysmographic waveform developed a high-frequency oscillation of ~7 Hz, which was not present in the skin during hypoxia. A weak correlation between the brain oximeter and proximal internal jugular vein oxygen levels was demonstrated, R2=0.24, P=0.01.ConclusionBrain oximeter oxygen saturations were relatively well preserved compared to the skin during hypoxia. These findings are consistent with the expected physiological responses and suggest skin oxygen levels did not markedly contaminate the brain oximeter signal.

The feature of brain oxygenation in the sleep cycle of healthy newborn babies

Noninvasive monitoring brain oxygenation with near-infrared spectroscopy (NIRS) is becoming a widely used in neonatology for determine the optimal target oxygen saturation during resuscitation of newborns, but its use in clinical practice for diagnostics and prognosis perinatal pathology is limited because intra and especially interpatient variability are too large for this aim. This study aimed to determine cerebral oximetry values during the sleep cycle and wakefulness in healthy full term newborns. 38 newborns (gestational age 38 weeks were included in this study (22 after normal birth I group and 16 after cesarean section). Near-infrared spectroscopy (CrSO2) from left fronto-parietal region was recorded in synchrony with polysomnography. Continuous cerebral CrSO2 were measured using near-infrared spectroscopy (Somanetic INVOS 5100C, USA). Fraction tissue oxygen extraction (FTOE) was calculated using SaO2 (pulse oximeter Radical Masimo) and CrSO2 (FTOE = (SаO2 CrSO2)/SаO2). CrSO2 and SаO2 were analyzed during 15 minutes polysomnography-defined quiet, active sleep and wakefulness (defined according to standard guidelines). The results: cerebral oxygen saturation varies with sleep-wake states: during active sleep (74,18 0,75%) was similar to the value in wakefulness (75,6 1,0%) and smaller than in quiet sleep (81,93 1,74%, р 0,001), but FTOE during active sleep was significantly higher (0,221 0,008% and 0,129 0,005%, p 0,001). There were no differences of rates between groups. The high oxygen consumption during REM sleep supports its role during postnatal brain functional development. The use of NIRS taking into account sleep structure will be new method for diagnostic and prognosis perinatal pathology CNS.

Design of Smart Brain Oxygenation Monitoring System for Estimating Cardiovascular Disease Severity

Clinically, cardiovascular disease (CVD) patients need physicians to suggest different exercise training and rehabilitation procedures to improve their cardiopulmonary function (CPF). In previous studies, several approaches, such as cardiopulmonary exercise testing (CPET), echocardiography and computed tomography angiography (CTA), were proposed to indirectly estimate the rehabilitation effect on CPF. However, the above approached require experienced operators and complex equipment. In this study, a smart and wearable brain oxygenation monitoring system without motion artifact and crosstalk is proposed to estimate the blood circulation state of brain tissue directly during incremental exercise. Moreover, the technique of neural network is also used for classifying different CPF groups from the indexes extracted from the measured hemoglobin parameters. The experimental results show that the defined indexes extracted from the hemoglobin parameters can present the state of CPF, and the proposed smart brain oxygenation monitoring system can also effectively and automatically classify different CPF groups from these indexes via artificial intelligence. The proposed system therefore may assist physicians in the clinical evaluation of the CVD severity and rehabilitation effect on CPF in the future.