Monitoring Of Cerebral Oxygenation Research Articles

Evaluation and analysis of neurocognitive dysfunction in patients with colorectal cancer after radical resection: A retrospective study.

With the continuous progress of colorectal cancer treatment technology, the survival rate of patients has improved significantly, but the problem of postoperative neurocognitive dysfunction has gradually attracted attention. To analyze the risk factors for delayed postoperative neurocognitive recovery (DNR) after laparoscopic colorectal cancer surgery and constructed a risk prediction model to provide an evidence-based reference for the prevention and treatment of DNR after laparoscopic colorectal cancer surgery. The clinical data of 227 patients with colorectal cancer who underwent laparoscopic surgery and regional cerebral saturation oxygenation (rScO2) monitoring at our hospital from March 2020 to July 2022 were retrospectively analyzed. Common factors and potential factors affecting postoperative DNR were used as analysis variables, and univariate analysis and multifactor analysis were carried out step by step to determine the predictors of the model and construct a risk prediction model. The predictive performance of the model was assessed by the receiver operating characteristic (ROC) curve, the calibration curve was used to assess the fit of the model to the data, and a nomogram was drawn. In addition, 30 patients who met the inclusion and exclusion criteria from January 2023 to July 2023 were selected for external verification of the prediction model. The incidence of postoperative DNR in the modeling group was 15.4% (35/227). Multivariate analysis revealed that age, years of education, diabetes status, and the lowest rScO2 value were the independent influencing factors of postoperative DNR (all P < 0.05). Accordingly, a DNR risk prediction model was constructed after laparoscopic colorectal cancer surgery. The area under the ROC curve of the model was 0.757 (95%CI: 0.676-0.839, P < 0.001), and the Hosmer-Lemeshow test of the calibration curve suggested that the model was well fitted (P = 0.516). The C-index for external validation of the row was 0.617. The DNR risk prediction model associated with rScO2 monitoring can be used for individualized assessment of patients undergoing laparoscopic colorectal cancer surgery and provides a clinical basis for the prevention of DNR after surgery.

An Innovative Approach in Emergency Medicine: Monitoring Brain Oxygenation with Cerebral Oximetry

The monitoring of cerebral oxygenation is a method that is not commonly integrated into the majority of existing emergency departments(ED), but it has attracted increasing attention, particularly in recent years. As the severity of ischemia escalates during cardiopulmonary resuscitation(CPR), the probability of both survival and favorable neurological outcomes diminishes. Therefore, the imperative development of methods to quantify the magnitude of ischemia, particularly cerebral ischemia, during resuscitation is critical for enhancing overall outcomes. Cerebral oximetry, using near-infrared spectroscopy, represents a noninvasive method for measuring brain oxygenation. The objective of this manuscript is to present an overview of the application of cerebral oximetry in the ED.

Home-based monitoring of cerebral oxygenation in response to postural changes using near-infrared spectroscopy.

Orthostatic hypotension (OH) is prevalent in older adults and can cause falls and hospitalization. Diagnostic intermittent blood pressure (BP) measurements are only a proxy for cerebral perfusion and do not reflect daily-life BP fluctuations. Near-infrared spectroscopy (NIRS)-measured cerebral oxygenation potentially overcomes these drawbacks. This study aimed to determine feasibility, face validity, and reliability of NIRS in the home environment. Ten participants with OH (2 female, mean age 77, SD 3.7) and 11 without OH (5 female, mean age 78, SD 6.7) wore a NIRS sensor at home on two different days for 10-11h per day. Preceded by a laboratory-situated test, cerebral oxygenation was measured during three standardized supine-stand tests per day and during unsupervised daily life activities. Data availability, quality, and user experience were assessed (feasibility), as well as differences in posture-related oxygenation responses between participants with and without OH and between symptomatic (dizziness, light-headedness, blurred vision) and asymptomatic postural changes (face validity). Reliability was assessed through repetitive supine-stand tests. Up to 80% of the standardized home-based supine-stand tests could be analyzed. Oxygenation recovery values were lower for participants with OH (p = 0 .03-0.15); in those with OH, oxygenation showed a deeper maximum drop for symptomatic than asymptomatic postural changes (p = 0.04). Intra-class correlation coefficients varied from 0.07 to 0.40, with no consistent differences over measurements. This proof-of-concept study shows feasibility and face validity of at-home oxygenation monitoring using NIRS, confirming its potential value for diagnosis and monitoring in OH and OH-related symptoms. Further data are needed for conclusions about reliability.

Assessing changes in regional cerebral hemodynamics in adults with a high-density full-head coverage time-resolved near-infrared spectroscopy device.

Cerebral oximeters have the potential to detect abnormal cerebral blood oxygenation to allow for early intervention. However, current commercial systems have two major limitations: (1)spatial coverage of only the frontal region, assuming that surgery-related hemodynamic effects are global and (2)susceptibility to extracerebral signal contamination inherent to continuous-wave near-infrared spectroscopy (NIRS). This work aimed to assess the feasibility of a high-density, time-resolved (tr) NIRS device (Kernel Flow) to monitor regional oxygenation changes across the cerebral cortex during surgery. The Flow system was assessed using two protocols. First, digital carotid compression was applied to healthy volunteers to cause a rapid oxygenation decrease across the ipsilateral hemisphere without affecting the contralateral side. Next, the system was used on patients undergoing shoulder surgery to provide continuous monitoring of cerebral oxygenation. In both protocols, the improved depth sensitivity of trNIRS was investigated by applying moment analysis. A dynamic wavelet filtering approach was also developed to remove observed temperature-induced signal drifts. In the first protocol ( years; five females, five males), hair significantly impacted regional sensitivity; however, the enhanced depth sensitivity of trNIRS was able to separate brain and scalp responses in the frontal region. Regional sensitivity was improved in the clinical study given the age-related reduction in hair density of the patients ( years; 14 females, 13 males). In five patients who received phenylephrine to treat hypotension, different scalp and brain oxygenation responses were apparent, although no regional differences were observed. The Kernel Flow has promise as an intraoperative neuromonitoring device. Although regional sensitivity was affected by hair color and density, enhanced depth sensitivity of trNIRS was able to resolve differences in scalp and brain oxygenation responses in both protocols.

Cerebral oxygenation monitoring in critically congenital heart neonates during cardiac catheterization

Cerebral oxygenation monitoring in critically congenital heart neonates during cardiac catheterization

Near-Infrared Spectroscopy (NIRS) in the Assessment of Cerebral Tissue Oxygenation (rSO2): Methodological Issues and Dilemmas

Introduction: Monitoring cerebral perfusion in patients with brain injury is a major clinical challenge. Monitoring cerebral oxygenation (rSO2) via NIRS was introduced in the early 1980s, and many clinicians believed it to be a valuable method for assessing cerebral perfusion and subsequent measures to optimize cerebral flow. The main problem with the use of NIRS is the presence of intermediate structures—the skin, skull, meninges, cerebrospinal fluid—and their influence on the test result. Therefore, it seems that NIRS assessment performed on a patient during brain death can give an idea of the magnitude of the influence of these intermediate structures on the monitoring result. Case presentation: We present a case study of cerebral oxygenation measurements in a patient undergoing a brain death diagnostic procedure. A clinical situation in which cerebral blood flow is stopped can give an idea of the specificity of this method, in particular of the influence of intermediate structures on the monitoring result. In this case, the result obtained using NIRS is increased by the patient’s oxygenation before the apnea test. The influence of chromophores in the tissues surrounding the CNS and reflections and scattering of the light wave spectrum have a very significant effect on the final result of cerebral saturation measurement. Discussion: The majority of observations in existing research describing changes in cerebral perfusion or its optimization may be burdened by the problem described here, i.e., by the significant influence of measured intermediate structure oxygenation. The specificity of NIRS in assessing cerebral perfusion requires careful analysis. The therapeutic implications of monitoring cerebral oxygenation with NIRS are of great importance, and based on the example presented and the literature provided, this method should be used with caution. It has been shown that in a patient with brain death, the result of NIRS oxygenation measurements depends on the structures surrounding the brain.

Results of using thoraflextm hybrid prothesis for the treatment of complex aortic disease at Viet Duc University Hospital

Background: The aim of this study was to introduce and evaluate the early results after the frozen elephant trunk (FET) procedure with ThoraflexTM Hybrid prothesis for the treatment of complex aortic disease at Viet Duc University Hospital. Methods: This is a retrospective descriptive study of all acceptable patients after the frozen elephant trunk (FET) procedure with ThoraflexTM Hybrid prothesis at Viet Duc University Hospital from January 2021 to May 2023. Results: There were 21 patients with a male rate of 85.7% and an average age 58.2±10 years old (range 40–73). History of patients with hypertension: 19 (90.5%); post-dissection aortic aneurysm: 2 (9.5%) patients. By cause, the number of patients with thoracic aortic aneurysm was 03 (14.3%), acute aortic dissection type A was 16 (76.1%), and aortic dissection type B was 02 (9.5%). In which there were 16 cases of emergency surgery (76.1%). Replacement of the aortic arch was performed under moderate hypothermic (280 °C on average) circulatory arrest and bilateral selective antegrade cerebral perfusion with permanent monitoring of cerebral tissue oxygenation by the MASIMO machine. Average cardio-pulmonary bypass time, aortic cross clamp time, distal hypothermic circulatory arrest time, and operating time were 137,5±22,9 minutes; 86,3±17,6 minutes; 25,2±8,9 minutes; and 7,7±10,3 hours. The average ventilation time, length of intensive care unit stay, and hospital stay were 7,2±9,7 days, 18,8±20,7 days, and 19,9 ± 6,5 days. There was one patient with post-operative cerebrospinal fluid drainage. No patient had bleeding complications, recurrent nerve palsy, reoperation, or in-hospital mortality. Conclusion: The initial results after the frozen elephant trunk procedure with ThoraflexTM Hybrid prothesis for the treatment of complex aortic disease at Viet Duc University Hospital were safe, good, and feasible.

Wearable fiber-free optical sensor for continuous monitoring of neonatal cerebral blood flow and oxygenation.

Unstable cerebral hemodynamics places preterm infants at high risk of brain injury. We adapted an innovative, fiber-free, wearable diffuse speckle contrast flow-oximetry (DSCFO) device for continuous monitoring of both cerebral blood flow (CBF) and oxygenation in neonatal piglets and preterm infants. DSCFO uses two small laser diodes as focused-point and a tiny CMOS camera as a high-density two-dimensional detector to detect spontaneous spatial fluctuation of diffuse laser speckles for CBF measurement, and light intensity attenuations for cerebral oxygenation measurement. The DSCFO was first validated against the established diffuse correlation spectroscopy (DCS) in neonatal piglets and then utilized for continuous CBF and oxygenation monitoring in preterm infants during intermittent hypoxemia (IH) events. Significant correlations between the DSCFO and DCS measurements of CBF variations in neonatal piglets were observed. IH events induced fluctuations in CBF, cerebral oxygenation, and peripheral cardiorespiratory vitals in preterm infants. However, no consistent correlation patterns were observed among peripheral and cerebral monitoring parameters. This pilot study demonstrated the feasibility of DSCFO technology to serve as a low-cost wearable sensor for continuous monitoring of multiple cerebral hemodynamic parameters. The results suggested the importance of multi-parameter measurements for understanding deep insights of peripheral and cerebral regulations. The innovative DSCFO technology may serve as a low-cost wearable sensor for continuous bedside monitoring of multiple cerebral hemodynamic parameters in neonatal intensive care units. Concurrent DSCFO and DCS measurements of CBF variations in neonatal piglet models generated consistent results. No consistent correlation patterns were observed among peripheral and cerebral monitoring parameters in preterm neonates, suggesting the importance of multi-parameter measurements for understanding deep insights of peripheral and cerebral regulations during IH events. Integrating and correlating multiple cerebral functional parameters with clinical outcomes may identify biomarkers for prediction and management of IH associated brain injury.

The Future of Neonatal Cerebral Oxygenation Monitoring: Directions After the SafeBoosC-III Trial

The Future of Neonatal Cerebral Oxygenation Monitoring: Directions After the SafeBoosC-III Trial

Cerebral oxygenation and perfusion kinetics monitoring of military aircrew at high G using novel fNIRS wearable system.

Real-time physiological episode (PE) detection and management in aircrew operating high-performance aircraft (HPA) is crucial for the US Military. This paper addresses the unique challenges posed by high acceleration (G-force) in HPA aircrew and explores the potential of a novel wearable functional near-infrared spectroscopy (fNIRS) system, named NIRSense Aerie, to continuously monitor cerebral oxygenation during high G-force exposure. The NIRSense Aerie system is a flight-optimized, wearable fNIRS device designed to monitor tissue oxygenation 13-20 mm below the skin's surface. The system includes an optical frontend adhered to the forehead, an electronics module behind the earcup of aircrew helmets, and a custom adhesive for secure attachment. The fNIRS optical layout incorporates near-distance, middle-distance, and far-distance infrared emitters, a photodetector, and an accelerometer for motion measurements. Data processing involves the modified Beer-Lambert law for computing relative chromophore concentration changes. A human evaluation of the NIRSense Aerie was conducted on six subjects exposed to G-forces up to +9 Gz in an Aerospace Environmental Protection Laboratory centrifuge. fNIRS data, pulse oximetry, and electrocardiography (HR) were collected to analyze cerebral and superficial tissue oxygenation kinetics during G-loading and recovery. The NIRSense Aerie successfully captured cerebral deoxygenation responses during high G-force exposure, demonstrating its potential for continuous monitoring in challenging operational environments. Pulse oximetry was compromised during G-loading, emphasizing the system's advantage in uninterrupted cerebrovascular monitoring. Significant changes in oxygenation metrics were observed across G-loading levels, with distinct responses in Deoxy-Hb and Oxy-Hb concentrations. HR increased during G-loading, reflecting physiological stress and the anti-G straining maneuver. The NIRSense Aerie shows promise for real-time monitoring of aircrew physiological responses during high G-force exposure. Despite challenges, the system provides valuable insights into cerebral oxygenation kinetics. Future developments aim for miniaturization and optimization for enhanced aircrew comfort and wearability. This technology has potential for improving anti-G straining maneuver learning and retention through real-time cerebral oxygenation feedback during centrifuge training.

Cerebral oxygenation monitoring for early detection of subarachnoid haemorrhage in infratentorial arteriovenous malformation undergoing embolisation: A case study.

Cerebral oxygenation monitoring for early detection of subarachnoid haemorrhage in infratentorial arteriovenous malformation undergoing embolisation: A case study.

Abstract 135: Identifying Optimal Mean Arterial Pressure in Cardiac Arrest Patients: Are Precision Medicine Approaches Feasible?

Introduction: Loss of cerebral autoregulation after cardiac arrest (CA) is associated with worse outcomes. A population-based mean arterial pressure (MAP) threshold, such as a post-resuscitation goal of ≥ 65 mmHg, may be insufficient to account for patient-specific factors, like autoregulatory failure. We investigated the feasibility of determining optimal MAP (MAP OPT ) using regional cerebral tissue oxygen monitoring with near-infrared spectroscopy (NIRS). Hypothesis: Autoregulatory failure and MAP OPT can be identified in individual patients after CA. Methods: We prospectively enrolled adult comatose CA survivors undergoing invasive MAP and regional cerebral oxygen monitoring with NIRS in an ICU between April 2022 and May 2023. Tissue oxygenation autoregulatory index (TOx) was derived using a moving Pearson correlation coefficient of 30 consecutive, 10-second averaged values of MAP and tissue oxygen index signals. TOx ≥ 0.3 defined impaired autoregulation. MAP values were divided into bins of 5 mmHg for which each corresponding TOx was averaged. Parabolic curve fitting determined the MAP value with the lowest associated TOx value (MAP OPT ). Results: Of 35 patients enrolled, 74.3% experienced out-of-hospital cardiac arrest with a mean (SD) age of 55.0 (13.9) years. Six (17.1%) patients survived to hospital discharge and 4 (11.4%) progressed to brain death. Monitoring was initiated at a median [IQR] of 14.9 [10.9 - 20.6] hours from CA for a duration of 47.5 [27.1 - 75.1] hours. The time spent with impaired autoregulation was 22.6 [18.4 - 31.6] % of the recording duration, corresponding to 10.1 [6.9 - 15.9] hours. MAP OPT could be identified in 33 (94.3%) patients and 47.7 [32.1 - 59.6] % of the recording duration. The average MAP OPT was &lt;75 mmHg in 2 (6.1%), 75 - 85 mmHg in 14 (42.4%), and &gt;85 mmHg in 17 (51.5%) patients. MAP OPT did not differ between survivors and non-survivors (mean (SD) 87.2 (9.6) vs. 88.2 (12.1) mmHg respectively, p=0.86). Conclusion: MAP OPT could be identified in all but two patients and calculated for half of the recording duration. Average MAP OPT was ≥ 75 mmHg in 94% of our cohort. Future studies are needed to evaluate whether targeting personalized physiologic thresholds influences outcomes.

Effects of permissive hypercapnia on intraoperative cerebral oxygenation and early postoperative cognitive function in older patients with non-acute fragile brain function undergoing laparoscopic colorectal surgery: protocol study

BackgroundPerioperative brain protection in older patients has been the focus of research recently; meanwhile, exploring the relationship between regional cerebral oxygen saturation (rSO2) and brain function in the perioperative period has been an emerging and challenging area—the difficulties related to the real-time monitoring of rSO2 and the choice of feasible interventions. As an advanced instrument for intraoperative rSO2 monitoring, the clinical application of near-infrared spectrum (NIRS) cerebral oxygen monitoring has gradually increased in popularity and is being recognized for its beneficial clinical outcomes in patients undergoing cardiac and noncardiac surgery. In addition, although sufficient evidence to support this hypothesis is still lacking, the effect of permissive hypercapnia (PHC) on rSO2 has expanded from basic research to clinical exploration. Therefore, monitoring intraoperative rSO2 in older patients with NIRS technology and exploring possible interventions that may change rSO2 and even improve postoperative cognitive performance is significant and clinically valuable.MethodsThis study is a single-center randomized controlled trial (RCT). 76 older patients are enrolled as subjects. Patients who meet the screening criteria will be randomly assigned 1:1 to the control and intervention groups. PHC-based mechanical ventilation will be regarded as an intervention. The primary outcome is the absolute change in the percent change in rSO2 from baseline to the completion of surgery in the intervention and control groups. Secondary outcomes mainly include observations of intraoperative cerebral oxygenation and metabolism, markers of brain injury, and assessments of patients' cognitive function using scale through postoperative follow-up.DiscussionThe findings of this RCT will reveal the effect of PHC on intraoperative rSO2 in older patients with nonacute fragile brain function (NFBF) and the approximate trends over time, and differences in postoperative cognitive function outcomes. We anticipate that the trial results will inform clinical policy decision-makers in clinical practice, enhance the management of intraoperative cerebral oxygen monitoring in older patients with comorbid NFBF, and provide guidance for clinical brain protection and improved postoperative cognitive function outcomes.Trial registrationChiCTR, ChiCTR2200062093, Registered 9/15/2022.

Intraoperative application of regional cerebral oxygen saturation monitoring for geriatric patients in China: a survey.

Regional cerebral oxygen saturation (rSO2) monitoring is a real-time and non-invasive technique for estimating the balance of regional cerebral oxygen supply and consumption. Despite the growing popularity of this monitoring technique, data regarding outcome benefits remain sparse and contradictory. This study was conducted to explore the popularity and understanding of cerebral oxygen saturation monitoring during anesthesia in geriatric patients. An online self-report questionnaire was distributed in March 2021 to various hospitals in China for dissemination to anesthesiologists. Questions surveyed cerebral oximetry equipment and utilization, demographics, and clinical practice of participants. In total, 447 anesthesiologists responded. Of these, 301 (67.3%) respondents reported that their hospitals were equipped with cerebral oximetry, which 274 anesthesiologists use during anesthesia. A high percentage of anesthesiologists chose to monitor rSO2 during cardiac surgery (77.4%, n = 212) and neurosurgery (40.5%, n = 111). Most anesthesiologists agreed that a 30% reduction from the rSO2 baseline requires intervention to avoid cerebral ischemia, mainly via elevating arterial pressure and fraction of inspired oxygen (FiO2). Of those without cerebral oximetry, 138 of 146 (94.5%) anesthesiologists were willing to monitor rSO2. In addition, 291 respondents believed that cerebral oxygen monitoring would help prevent postoperative cognitive dysfunction. Our survey indicated that the prevalence of cerebral oximetry remains relatively low, while almost all anesthesiologists expressed their willingness to use rSO2 monitoring in geriatric anesthesia. Heterogeneity in clinical practice was identified, indicating relevant knowledge gaps that should encourage further clinical research to optimize treatment.

Insights into Neonatal Cerebral Autoregulation by Blood Pressure Monitoring and Cerebral Tissue Oxygenation: A Qualitative Systematic Review.

The aim of this qualitative systematic review was to identify publications on blood pressure monitoring in combination with cerebral tissue oxygenation monitoring during the first week after birth focusing on cerebral autoregulation. A systematic search was performed on PubMed. The following search terms were used: infants/newborn/neonates, blood pressure/systolic/diastolic/mean/MAP/SAP/DAP, near-infrared spectroscopy, oxygenation/saturation/oxygen, and brain/cerebral. Additional studies were identified by a manual search of references in the retrieved studies and reviews. Only human studies were included. Thirty-one studies focused on preterm neonates, while five included preterm and term neonates. In stable term neonates, intact cerebral autoregulation was shown by combining cerebral tissue oxygenation and blood pressure during immediate transition, while impaired autoregulation was observed in preterm neonates with respiratory support. Within the first 24 h, stable preterm neonates had reduced cerebral tissue oxygenation with intact cerebral autoregulation, while sick neonates showed a higher prevalence of impaired autoregulation. Further cardio-circulatory treatment had a limited effect on cerebral autoregulation. Impaired autoregulation, with dependency on blood pressure and cerebral tissue oxygenation, increased the risk of intraventricular hemorrhage and abnormal neurodevelopmental outcomes. Integrating blood pressure monitoring with cerebral tissue oxygenation measurements has the potential to improve treatment decisions and optimizes neurodevelopmental outcomes in high-risk neonates.

Association between Bilateral Selective Antegrade Cerebral Perfusion and Postoperative Ischemic Stroke in Patients with Emergency Surgery for Acute Type A Aortic Dissection-Single Centre Experience.

Acute type A aortic dissection (ATAAD) is a surgical emergency with a mortality of 1-2% per hour. Since its discovery over 200 years ago, surgical techniques for repairing a dissected aorta have evolved, and with the introduction of hypothermic circulatory arrest and cerebral perfusion, complex techniques for replacing the entire aortic arch were possible. However, postoperative neurological complications contribute significantly to mortality in this group of patients. The aim of this study was to determine the association between different bilateral selective antegrade cerebral perfusion (ACP) times and the incidence of postoperative ischemic stroke in patients with emergency surgery for ATAAD. Patients with documented hemorrhagic or ischemic stroke, clinical signs of stroke or neurological dysfunction prior to surgery, that died on the operating table or within 48 h after surgery, from whom the postoperative neurological status could not be assessed, and with incomplete medical records were excluded from this study. The diagnosis of postoperative stroke was made using head computed tomography imaging (CT) when clinical suspicion was raised by a neurologist in the immediate postoperative period. For selective bilateral antegrade cerebral perfusion, we used two balloon-tipped cannulas inserted under direct vision into the innominate artery and the left common carotid artery. Each cannula is connected to a separate pump with an independent pressure line. Near-infrared spectroscopy was used in all cases for cerebral oxygenation monitoring. The circulatory arrest was initiated after reaching a target core temperature of 25-28 °C. In total, 129 patients were included in this study. The incidence of postoperative ischemic stroke documented on a head CT was 24.8% (31 patients), and postoperative death was 20.9% (27 patients). The most common surgical technique performed was supravalvular ascending aorta and Hemiarch replacement with a Dacron graft in 69.8% (90 patients). The mean cardiopulmonary bypass time was 210 +/- 56.874 min, the mean aortic cross-clamp time was 114.775 +/- 34.602 min, and the mean cerebral perfusion time was 37.837 +/- 18.243 min. Using logistic regression, selective ACP of more than 40 min was independently associated with postoperative ischemic stroke (OR = 3.589; 95%CI = 1.418-9.085; p = 0.007). Considering the high incidence of postoperative stroke in our study population, we concluded that bilateral selective ACP should be used with caution, especially in patients with severely calcified ascending aorta and/or aortic arch and supra-aortic vessels. All efforts should be made to minimize the duration of circulatory arrest when using bilateral selective ACP with a target of less than 30 min, in hypothermia, at a body temperature of 25-28 °C.

AWAreness during REsuscitation - II: A multi-center study of consciousness and awareness in cardiac arrest

IntroductionCognitive activity and awareness during cardiac arrest (CA) are reported but ill understood. This first of a kind study examined consciousness and its underlying electrocortical biomarkers during cardiopulmonary resuscitation (CPR). MethodsIn a prospective 25-site in-hospital study, we incorporated a) independent audiovisual testing of awareness, including explicit and implicit learning using a computer and headphones, with b) continuous real-time electroencephalography(EEG) and cerebral oxygenation(rSO2) monitoring into CPR during in-hospital CA (IHCA). Survivors underwent interviews to examine for recall of awareness and cognitive experiences. A complementary cross-sectional community CA study provided added insights regarding survivors’ experiences. ResultsOf 567 IHCA, 53(9.3%) survived, 28 of these (52.8%) completed interviews, and 11(39.3%) reported CA memories/perceptions suggestive of consciousness. Four categories of experiences emerged: 1) emergence from coma during CPR (CPR-induced consciousness [CPRIC]) 2/28(7.1%), or 2) in the post-resuscitation period 2/28(7.1%), 3) dream-like experiences 3/28(10.7%), 4) transcendent recalled experience of death (RED) 6/28(21.4%). In the cross-sectional arm, 126 community CA survivors’ experiences reinforced these categories and identified another: delusions (misattribution of medical events). Low survival limited the ability to examine for implicit learning. Nobody identified the visual image, 1/28(3.5%) identified the auditory stimulus. Despite marked cerebral ischemia (Mean rSO2 = 43%) normal EEG activity (delta, theta and alpha) consistent with consciousness emerged as long as 35–60 minutes into CPR. ConclusionsConsciousness. awareness and cognitive processes may occur during CA. The emergence of normal EEG may reflect a resumption of a network-level of cognitive activity, and a biomarker of consciousness, lucidity and RED (authentic “near-death” experiences).

The importance of monitoring cerebral oxygenation in non brain injured patients.

Over the past few years, the use of non-invasive neuromonitoring in non-brain injured patients has increased, as a result of the recognition that many of these patients are at risk of brain injury in a wide number of clinical scenarios and therefore may benefit from its application which allows interventions to prevent injury and improve outcome. Among these, are post cardiac arrest syndrome, sepsis, liver failure, acute respiratory failure, and the perioperative settings where in the absence of a primary brain injury, certain groups of patients have high risk of neurological complications. While there are many neuromonitoring modalities utilized in brain injured patients, the majority of those are either invasive such as intracranial pressure monitoring, require special skill such as transcranial Doppler ultrasonography, or intermittent such as pupillometry and therefore unable to provide continuous monitoring. Cerebral oximetry using Near infrared Spectroscopy, is a simple non invasive continuous measure of cerebral oxygenation that has been shown to be useful in preventing cerebral hypoxemia both within the intensive care unit and the perioperative settings. At present, current recommendations for standard monitoring during anesthesia or in the general intensive care concentrate mainly on hemodynamic and respiratory monitoring without specific indications regarding the brain, and in particular, brain oximetry. The aim of this manuscript is to provide an up-to-date overview of the pathophysiology and applications of cerebral oxygenation in non brain injured patients as part of non-invasive multimodal neuromonitoring in the early identification and treatment of neurological complications in this population.

Near-infrared spectroscopy monitoring of neonatal cerebrovascular reactivity: where are we now?

Cerebrovascular reactivity defines the ability of the cerebral vasculature to regulate its resistance in response to both local and systemic factors to ensure an adequate cerebral blood flow to meet the metabolic demands of the brain. The increasing adoption of near-infrared spectroscopy (NIRS) for non-invasive monitoring of cerebral oxygenation and perfusion allowed investigation of the mechanisms underlying cerebrovascular reactivity in the neonatal population, confirming important associations with pathological conditions including the development of brain injury and adverse neurodevelopmental outcomes. However, the current literature on neonatal cerebrovascular reactivity is mainly still based on small, observational studies and is characterised by methodological heterogeneity; this has hindered the routine application of NIRS-based monitoring of cerebrovascular reactivity to identify infants most at risk of brain injury. This review aims (1) to provide an updated review on neonatal cerebrovascular reactivity, assessed using NIRS; (2) to identify critical points that need to be addressed with targeted research; and (3) to propose feasibility trials in order to fill the current knowledge gaps and to possibly develop a preventive or curative approach for preterm brain injury. IMPACT: NIRS monitoring has been largely applied in neonatal research to assess cerebrovascular reactivity in response to blood pressure, PaCO2 and other biochemical or metabolic factors, providing novel insights into the pathophysiological mechanisms underlying cerebral blood flow regulation. Despite these insights, the current literature shows important pitfalls that would benefit to be addressed in a series of targeted trials, proposed in the present review, in order to translate the assessment of cerebrovascular reactivity into routine monitoring in neonatal clinical practice.

Effects of Different Hemoglobin Levels on Near-Infrared Spectroscopy-Derived Cerebral Oxygen Saturation in Elderly Patients Undergoing Noncardiac Surgery

Background: Near-infrared spectroscopy (NIRS) is a commonly used technique to evaluate tissue oxygenation and prevent harmful cerebral desaturation in the perioperative setting. The aims of the present study were to assess whether surgery-related anemia can be detected via NIRS of cerebral oxygen saturation and to investigate the effects of different perioperative transfusion strategies on cerebral oxygenation, potentially affecting transfusion decision-making. Study Design and Methods: Data from the ongoing multicenter LIBERAL-Trial (liberal transfusion strategy to prevent mortality and anemia-associated ischemic events in elderly noncardiac surgical patients, LIBERAL) were used. In this single-center sub-study, regional cerebral oxygenation saturation (rSO₂) was evaluated by NIRS at baseline, pre-, and post-RBC transfusion. The obtained values were correlated with blood gas analysis-measured Hb concentrations. Results: rSO₂ correlated with Hb decline during surgery (r = 0.35, p < 0.0001). Different RBC transfusion strategies impacted rSO₂ such that higher Hb values resulted in higher rSO₂. Cerebral desaturation occurred at lower Hb values more often. Discussion: Cerebral oxygenation monitoring using NIRS provides noninvasive rapid and continuous information regarding perioperative alterations in Hb concentration without the utilization of patients’ blood for blood sampling. Further investigations are required to demonstrate if cerebral rSO₂ may be included in future individualized transfusion decision strategies.