Near-infrared Spectroscopy Monitoring Research Articles

Enhancing Early Detection of Sepsis in Neonates through Multimodal Biosignal Integration: A Study of Pulse Oximetry, Near-Infrared Spectroscopy (NIRS), and Skin Temperature Monitoring

Enhancing Early Detection of Sepsis in Neonates through Multimodal Biosignal Integration: A Study of Pulse Oximetry, Near-Infrared Spectroscopy (NIRS), and Skin Temperature Monitoring

Effect of near-infrared spectroscopy on postoperative delirium in cardiac surgery with cardiopulmonary bypass: a systematic review and meta-analysis.

Postoperative delirium (POD) is a common anesthetic side effect in cardiac surgery. However, the role of oxygen saturation monitoring in reducing postoperative delirium has been controversial. Therefore, this meta-analysis aimed to analyze whether NIRS monitoring during cardiac surgery under cardiopulmonary bypass could reduce the incidence of postoperative delirium. PubMed, Web of Science, Cochrane Library, Embase and China National Knowledge Infrastructure (CNKI) databases were systematically searched using the related keywords for randomized-controlled trials (RCTs) published from their inception to March 16, 2024. This review was conducted by the Preferred Reporting Project and Meta-Analysis Statement (PRISMA) guidelines for systematic review. The primary outcome was postoperative delirium, and the second outcomes included the length of ICU stay, the incidence of kidney-related adverse outcomes, and the incidence of cardiac-related adverse outcomes. The incidence of postoperative delirium could be reduced under the guidance of near-infrared spectroscopy monitoring (OR, 0.657; 95% CI, 0.447-0.965; P = 0.032; I2 = 0%). However, there were no significant differences in the length of ICU stay (SMD, 0.005 days; 95% CI, -0.135-0.146; P = 0.940; I2 = 39.3%), the incidence of kidney-related adverse outcomes (OR, 0.761; 95% CI, 0.386-1.500; P = 0.430; I2 = 0%), and the incidence of the cardiac-related adverse outcomes (OR, 1.165; 95% CI, 0.556-2.442; P = 0.686; I2 = 0%) between the two groups. Near-infrared spectroscopy monitoring in cardiac surgery with cardiopulmonary bypass helps reduce postoperative delirium in patients. PROSPERO, identifier, CRD42023482675.

Physiologic Determinants of Near-Infrared Spectroscopy-Derived Cerebral and Tissue Oxygen Saturation Measurements in Critically Ill Patients.

Near-infrared spectroscopy (NIRS) is a potentially valuable modality to monitor the adequacy of oxygen delivery to the brain and other tissues in critically ill patients, but little is known about the physiologic determinants of NIRS-derived tissue oxygen saturations. The purpose of this study was to assess the contribution of routinely measured physiologic parameters to tissue oxygen saturation measured by NIRS. An observational sub-study of patients enrolled in the Role of Active Deresuscitation After Resuscitation-2 (RADAR-2) randomized feasibility trial. Two ICUs in the United Kingdom. Patients were recruited for the RADAR-2 study, which compared a conservative approach to fluid therapy and deresuscitation with usual care. Those included in this sub-study underwent continuous NIRS monitoring of cerebral oxygen saturations (SctO2) and quadriceps muscle tissue saturations (SmtO2). Synchronized and continuous mean arterial pressure (MAP), heart rate (HR), and pulse oximetry (oxygen saturation, Spo2) measurements were recorded alongside NIRS data. Arterial Paco2, Pao2, and hemoglobin concentration were recorded 12 hourly. Linear mixed effect models were used to investigate the association between these physiologic variables and cerebral and muscle tissue oxygen saturations. Sixty-six patients were included in the analysis. Linear mixed models demonstrated that Paco2, Spo2, MAP, and HR were weakly associated with SctO2 but only explained 7.1% of the total variation. Spo2 and MAP were associated with SmtO2, but together only explained 0.8% of its total variation. The remaining variability was predominantly accounted for by between-subject differences. Our findings demonstrated that only a small proportion of variability in NIRS-derived cerebral and tissue oximetry measurements could be explained by routinely measured physiologic variables. We conclude that for NIRS to be a useful monitoring modality in critical care, considerable further research is required to understand physiologic determinants and prognostic significance.

Cerebral oxygen metabolism and brain electrical activity of healthy full-term neonates in high-altitude areas: a multicenter clinical research protocol

Further evidence is needed to explore the impact of high-altitude environments on the neurologic function of neonates. Non-invasive techniques such as cerebral near-infrared spectroscopy and amplitude-integrated electroencephalography can provide data on cerebral oxygenation and brain electrical activity. This study will conduct multiple cerebral near-infrared spectroscopy and amplitude-integrated electroencephalography monitoring sessions at various time points within the first 3 days postpartum for healthy full-term neonates at different altitudes. The obtained data on cerebral oxygenation and brain electrical activity will be compared between different altitudes, and corresponding reference ranges will be established. The study involves 6 participating centers in the Chinese High Altitude Neonatal Medicine Alliance, with altitude gradients divided into 4 categories: 800 m, 1 900 m, 2 400 m, and 3 500 m, with an anticipated sample size of 170 neonates per altitude gradient. This multicenter prospective cohort study aims to provide evidence supporting the impact of high-altitude environments on early brain function and metabolism in neonates.

393 Cerebral Oximetry Using the USIC Protocol Is a Reliable Tool for Indicating Selective Intraluminal Shunting During Carotid Endarterectomy

INTRODUCTION: Indication to selective shunting during carotid endarterectomy (CEA) is based on monitoring during the procedure. Cerebral oximetry (CO) using near-infrared spectroscopy (NIRS) is one of the monitoring tools but no clear cut off value for an intraluminal shunt insertion has been established. METHODS: 125 patients underwent CEA under LA and were monitored clinically through the whole procedure. The patients also underwent bilateral NIRS monitoring during the surgery. During the monitoring period, we first clamped the external carotid artery (ECA), and after a 1 minute delay followed by clipping the internal carotid artery (ICA). The decrease in the cerebral oximetry values was analyzed separately after selective ICA clipping (ÚstÍ Selective Internal carotid artery Clamping “USIC” protocol). The decision to use a shunt was based solely on clinical symptomatology but the NIRS data were recorded and analyzed. All patients underwent DWI before and after CEA. RESULTS: One hundred and six patients (85%) underwent CEA without clinical deterioration while 19 patients (15%) clinically deteriorated during surgery. The mean drop in the cerebral oximetry after selective ICA clamping in clinically stable patients was 6% while in patients with clinical deterioration the NIRS decreased by 15% (p < 0.05). When we set the cut-off value for selective shunting as a 10% decrease of the ipsilateral cerebral oximetry after selective ICA clamping, the sensitivity of the technique was 100% and the specificity 83%. CONCLUSIONS: Our study showed that a 10% decrease in the ipsilateral brain tissue oximetry after selective cross-clamping the ICA provides a reliable cut-off for selective shunting during CEA. More, bilateral NIRS monitoring allows differentiation between systemic or local events leading to brain hypoxia.

Identifying the Influences on Network Formation in Structural Isomers of Multifunctional Epoxies Using Near-Infrared Spectroscopy.

The network formation of four epoxy-rich formulations of the structural isomers of triglycidyl aminophenol and diaminodiphenyl sulfone has been monitored by using two complementary techniques, near-infrared spectroscopy and resin temperature monitoring. The differences between these networks have been described using the concentration of epoxide, primary amine, secondary amine, and tertiary amine functional groups and the actual temperature of the resin compared to the oven temperature during the cure schedule. It was found that initially, the 3,3'-diaminodiphenyl sulfone (33'DDS) formulations were more reactive and primary amines were completely consumed before the 4,4'-diaminodiphenyl sulfone (44'DDS) formulations. Secondary amines were formed more quickly in 33'DDS formulations compared to 44'DDS. The triglycidyl-meta-aminophenol (TGmAP) formulations consumed secondary amines and produced tertiary amines faster than the triglycidyl-para-aminophenol (TGpAP) formulations, indicating higher levels of cross-linking occurred earlier in the curing reaction. Etherification occurred much earlier in the TGpAP formulations than in the TGmAP formulations. Results suggest that internal cyclization occurs in the three meta isomer-containing formulations, and a corresponding lack of this effect in TGpAP/44'DDS results in a more homogeneous cross-linked network.

Development of near-infrared spectroscopy calibration model and monitoring software: For monitoring hexamethylenetetramine concentration in hexamethylenetetramine–acetic acid solution

In recent years, near-infrared spectroscopy has been increasingly used in chemical engineering processes. However, accurately and in real-time monitoring concentrations remains highly challenging. This study presents a method for accurately monitoring the hexamethylenetetramine concentration in hexamethylenetetramine-acetic acid solution by integrating near-infrared spectroscopy with software techniques. Compared to the methods of zero mean standardization (Z-score), standard normal variate (SNV), first derivative (D1), second derivative (D2), and vector normalization (VN), the Savitzky-Golay first derivative (SGFD) method effectively addresses issues related to baseline drift, noise, and other interferences. This results in clearer identification of characteristic absorption peaks of different components and a significant improvement in the accuracy of the analysis. The study combined the uninformative variable elimination (UVE), differential evolution (DE), and moth flame optimization (MFO) algorithms to optimize a feature wavenumber selection method, which reduced the number of variables by 78.74 %, and the values of root mean square error of calibration set (RMSEC) and root mean square error of prediction (RMSEP) by 18.86 % and 30.38 %, respectively. Additionally, the analytical method was integrated with real-time monitoring software, enabling the monitoring of hexamethylenetetramine concentration. This integration supports the improvement of the quality and safety of the manufacturing process. The results demonstrate the potential application of near-infrared spectroscopy in real-time monitoring and automated control of chemical processes in the chemical industry.

Near-infrared spectroscopy monitoring in severe pediatric abusive head trauma.

Abusive head trauma (AHT) is one of the most devastating forms of pediatric traumatic brain injury (TBI). It commonly presents with seizures, which may contribute to poor neurological outcome following trauma. Noninvasive near-infrared spectroscopy (NIRS) neuromonitoring may provide information on cerebral oxygenation and perfusion. In this study, the authors evaluated whether NIRS regional cerebral oxygen saturation (rSO2) values were associated with seizure activity confirmed by electroencephalography (EEG) and whether NIRS neuromonitoring could aid in seizure detection in patients with severe AHT. The authors retrospectively analyzed pediatric patients aged ≤ 18 years who were admitted to a quaternary urban pediatric hospital from 2016 to 2022 with severe AHT, who received NIRS and EEG monitoring during their hospital course. They evaluated clinical presentation and hospital course, including imaging findings, EEG findings, and NIRS rSO2 values. Nineteen patients with severe AHT were monitored with both EEG and NIRS. The median age was 3.4 months, and 14 patients experienced seizures confirmed by EEG. On average, rSO2 values before, during, and after seizure did not differ significantly. However, within individual patients, bilateral regional NIRS rSO2 (bilateral forehead region) was seen to rise in the hour preceding seizure activity and during periods of frequent seizure activity, confirmed by EEG in the bilateral frontal-midline brain regions. To the best of the authors' knowledge, this is the largest study to analyze NIRS and seizures confirmed by EEG in the severe AHT population. The relationship between NIRS values and seizures in this series of pediatric patients with severe AHT suggests that, overall, regional NIRS cannot predict early seizures. However, increased cerebral oxygenation preceding seizure activity and during seizure activity may be detected by regional NIRS in certain patients with local seizure activity. Future studies with larger sample sizes may help elucidate the relationship between seizures and cerebral oxygenation in different regions in severe pediatric AHT.

Near-Infrared Spectroscopy and Continuous Glucose Monitoring During Therapeutic Hypothermia.

The relation between glucose homeostasis and cerebral blood flow (CBF) and their correlation to outcome in neonatal hypoxic-ischemic encephalopathy are unclear. In this short communication, we tried to determine whether changes in regional oxygen saturation (rSO2), as measured by near-infrared spectroscopy (NIRS), in asphyxiated neonates during therapeutic hypothermia correlate with the glycemic profile and whether NIRS and continuous glucose monitoring are useful in identifying cooled asphyxiated neonates at high risk of brain injury. Although there was no correlation between blood glucose and CBF in this small cohort of asphyxiated neonates (13 neonates admitted to the IRCCS Giannina Gaslini NICU in Genoa between March and September 2021), after 24 h of life, increased rSO2 and glucose variability with a tendency toward hyperglycemia distinguished neonates who subsequently acquired brain injury from those who did not. As a result of this, it may be possible to monitor cerebral perfusion and metabolic changes as soon as possible after delivery in order to prevent poorer outcomes.

Near-Infrared Spectroscopy Monitoring to Detect Changes in Cerebral and Renal Perfusion During Hypovolemic Shock, Volume Resuscitation, and Vasoconstriction.

Rapidly changing hemodynamic conditions, such as uncontrolled hemorrhage and the resulting hypovolemic shock, are a common contributor to active duty military deaths. These conditions can cause cerebral desaturation, and outcomes may improve when regional cerebral oxygen saturation (CrSO2) is monitored using near-infrared spectroscopy (NIRS) and desaturation episodes are recognized and reversed. The purpose of this porcine study was to investigate the ability of NIRS monitoring to detect changes in regional cerebral and regional renal perfusion during hypovolemia, resuscitation by volume infusion, and vasoconstriction. Hemorrhagic shock was induced by removing blood through a central venous catheter until mean arterial pressure (MAP) was <40 mmHg. Each blood removal step was followed by a 10-minute stabilization period, during which cardiac output, blood pressure, central venous pressure, blood oxygen saturation, and CrSO2 and regional renal oxygen saturation (RrSO2) were measured. Shock was reversed using blood infusion and vasoconstriction separately until MAP returned to normal. Statistical comparisons between groups were performed using the paired t-test or the Wilcoxon signed-rank test. Using volume resuscitation, both CrSO2 and RrSO2 returned to normal levels after hypovolemia. Blood pressure management with phenylephrine returned CrSO2 levels to normal, but RrSO2 levels remained significantly lower compared to the pre-hemorrhage values (P < .0001). Comparison of the percent CrSO2 as a function of MAP showed that CrSO2 levels approach baseline when a normal MAP is reached during volume resuscitation. In contrast, a significantly higher MAP was required to return to baseline CrSO2 during blood pressure management with phenylephrine (P < .0001). Evaluation of carotid blood flow and CrSO2 indicated that during induction of hypovolemia, the two measures are strongly correlated. In contrast, there was limited correlation between carotid blood flow and CrSO2 during blood infusion. This study demonstrated that it is possible to restore CrSO2 by manipulating MAP with vasoconstriction, even in profound hypotension. However, MAP manipulation may result in unintended consequences for other organs, such as the kidney, if the tissue is not reoxygenated sufficiently. The clinical implications of these results and how best to respond to hypovolemia in the pre-hospital and hospital settings should be elucidated by additional studies.

Differences in Cerebral Tissue Oxygenation in Preterm Neonates Receiving Adult or Cord Blood Red Blood Cell Transfusions

Repeated transfusions in preterm neonates with anemia of prematurity replace fetal hemoglobin (HbF) with adult Hb (HbA), which has a low oxygen affinity. The reduction of HbF is associated with a higher incidence of retinopathy of prematurity (ROP). To assess whether HbF and HbA are differently associated with cerebral tissue oxygenation in preterm neonates. This cohort study was a single-center, pilot study on cerebral oxygenation kinetics in preterm neonates with a gestational age between 24.0 weeks and 27.9 weeks who were admitted to the neonatal intensive care unit of Policlinico Universitario A. Gemelli IRCCS from December 27, 2021, to May 15, 2023. This study was ancillary to the ongoing, double-blind, multicenter Umbilical or Adult Donor Red Blood Cells in Extremely Low Gestational Age Neonates and Retinopathy of Prematurity (BORN) randomized clinical trial. The BORN trial outcome was ROP severity in neonates randomized to receive standard packed red blood cell (PRBC) transfusions obtained from RBCs of adult donors (A-RBCs) or from cord blood (CB-RBCs). According to standard procedures at the institute's neonatal intensive care unit, patients concurrently received continuous cerebral near-infrared spectroscopy (NIRS) monitoring. This cohort study was not prespecified in the trial protocol. Transfusion with A-RBCs or CB-RBCs. The main outcome was the kinetics of cerebral regional oxygen saturation (crSO2) and cerebral fraction of tissue oxygen extraction (cFTOE) associated with A-RBC or CB-RBC transfusions. Cerebral NIRS monitoring was performed by neonatologists and nurses, who were blinded to the PRBC type. The NIRS monitoring was conducted starting with the blood product order, during transfusion, and for the subsequent 24 hours after transfusion completion. The mean treatment effects of A-RBCs or CB-RBCs were quantified using a linear mixed model for repeated measures. Of 23 randomized neonates, 17 (11 male [64.7%]; median gestational age at birth, 25.6 weeks [IQR, 25.3-26.1 weeks]) with a median birth weight of 840 g (IQR, 580-900 g) were included in the study; NIRS was evaluated for 42 transfusion episodes, of which 22 were A-RBCs and 20 were CB-RBCs. Globally considering all posttransfusion time points, the overall crSO2 covariate-adjusted mean after CB-RBC transfusions was 5.27% lower (95% CI, 1.20%-9.34%; P = .01) than that after A-RBC transfusions, while the cFTOE after CB-RBC transfusions was 6.18% higher (95% CI, 1.66%-10.69%; P = .009) than that after A-RBCs. The findings of this cohort study suggest that A-RBC transfusions may be associated with more oxygen delivery to cerebral tissues of preterm neonates than transfusions from CB-RBCs. This finding may explain the previously observed association between low HbF and high ROP risk. It also suggests that use of CB to meet the RBC transfusion needs of neonates with a gestational age of less than 28 weeks may protect cerebral tissues from overexposure to oxygen.

Abstract 185: Regional Oxygen Saturation and Capnography Monitoring During Resuscitation After Cardiac Arrest in a Swine Pediatric ARDS Model

Introduction: Survival and outcomes after cardiac arrest (CA) depend largely on the effectiveness of cardiopulmonary resuscitation (CPR). Traditional invasive methods of monitoring CPR can be challenging out-of-hospital and are lacking in more than 50% of in-hospital pediatric CA. Regional oxygen saturation (rSO 2 ) monitoring with Near Infrared Spectroscopy (NIRS) and volumetric capnography offers a noninvasive approach that could potentially overcome these challenges. Aim: To determine the feasibility and effectiveness of NIRS and volumetric capnography monitoring in a swine model of pediatric hypoxia induced CA. Approach: Juvenile pigs were sedated and mechanically ventilated. Mild to moderate Acute Respiratory Distress Syndrome (ARDS) was induced by continuous oleic acid infusion. Respiratory and hemodynamic variables were monitored using invasive and noninvasive (NIRS and capnography) monitoring to assess efficacy of CPR. Animals were randomized into one of the two groups: High-quality CPR (hqCPR) to achieve coronary perfusion pressure of 25-30 mmHg and low-quality CPR (lqCPR) to achieve coronary perfusion pressure of 10-15 mmHg. Trajectories over time were analyzed using regression analyses. The discriminatory ability to distinguish between groups based on trajectories were analyzed using receiver operating characteristics curve (ROC) analysis. Results: 39 animals (23±3 kg) were included in our study. In the hqCPR group, there are generally higher values for cerebral and renal rSO 2 , ETCO 2 , volume of CO 2 elimination (VCO 2 ), and carotid blood flow, compared to the lqCPR group (p&lt;0.0001). Cerebral and renal rSO 2 values increase over time, while ETCO 2 , VCO 2 , and carotid flow values decrease in the hqCPR group. Cerebral rSO2 had a ROC AUC of 0.76 (95% CI: 0.58-0.94), whereas renal rSO2 had a ROC AUC of 0.54 (95% CI: 0.22-0.87) representing nearly no discrimination ability. ETCO 2 had a ROC AUC of 0.66 (95% CI: 0.49-0.84), whereas VCO 2 had a ROC AUC of 0.62 (95% CI: 0.38-0.85). Conclusions: Higher mean cerebral rSO2 values during CPR might be used to assess quality of CPR effectiveness and provide real-time adjustments as needed. This could guide healthcare providers in optimizing CPR quality and improving outcomes for cardiac arrest patients.

Sex Differences in Test-Retest Reliability of Near-Infrared Spectroscopy During Postocclusive Reactive Hyperemia of the Vastus Lateralis.

Shoemaker, ME, Smith, CM, Gillen, ZM, and Cramer, JT. Sex differences in test-retest reliability of near-infrared spectroscopy during postocclusive reactive hyperemia of the vastus lateralis. J Strength Cond Res 38(2): e40-e48, 2024-The purpose of this study was to determine test-retest reliability for vascular reactivity measures and ranges for normalization of near-infrared spectroscopy (NIRS) variables from the vastus lateralis using postocclusive reactive hyperemia (PORH) procedure in male subjects, female subjects, and combined. Concentrations of oxygenated hemoglobin (Hb) + myoglobin (Mb) (O 2 Hb) and deoxygenated Hb + Mb (HHb) to derive total Hb + Mb (THb), difference in Hb + Mb signal (Hbdiff), and muscle tissue oxygen saturation (StO 2 ) from the vastus lateralis were measured during the PORH in 12 male subjects (age: 23.17 ± 1.77 years; stature: 180.88 ± 4.59 cm; and mass: 81.47 ± 9.68 kg) and 10 female subjects (age: 23.80 ± 2.07 years; stature: 165.95 ± 4.92 cm; and mass: 70.93 ± 10.55 kg) on 2 separate days. Adipose tissue thickness at the NIRS site was measured with ultrasonography. There were no significant differences between the mean values from visit 1 to visit 2 ( p > 0.076-0.985). In the composite sample, intraclass correlation coefficient (ICC) and coefficient of variation (CV) ranged from 0.35 to 0.91 and 4.74 to 39.18%, respectively. In male subjects, ICC and CV values ranged from 0.57 to 0.89 and 2.44 to 28.55%, respectively. In female subjects, ICC and CV values ranged from -0.05 to 0.75 and 7.83 to 61.19%, respectively. Although NIRS variables were overall reliable during PORH, when separated by sex, reliability in male subjects generally increased, whereas female subjects were not reliable, suggesting adipose tissue thickness may be a contributing factor. Understanding sex differences in reliability is important when using this technique for normalization or examining vascular reactivity during athletic performance. With greater utilization of NIRS monitoring in athletes to examine training adaptations, it is important for practitioners to understand the capabilities and potential limitations of the tool.

Tissue Oxygenation Changes After Transfusion and Outcomes in Preterm Infants

Preterm infants with varying degrees of anemia have different tissue oxygen saturation responses to red blood cell (RBC) transfusion, and low cerebral saturation may be associated with adverse outcomes. To determine whether RBC transfusion in preterm infants is associated with increases in cerebral and mesenteric tissue saturation (Csat and Msat, respectively) or decreases in cerebral and mesenteric fractional tissue oxygen extraction (cFTOE and mFTOE, respectively) and whether associations vary based on degree of anemia, and to investigate the association of Csat with death or neurodevelopmental impairment (NDI) at 22 to 26 months corrected age. This was a prospective observational secondary study conducted among a subset of infants between August 2015 and April 2017 in the Transfusion of Prematures (TOP) multicenter randomized clinical trial at 16 neonatal intensive care units of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network. Preterm neonates with gestational age 22 to 28 weeks and birth weight 1000 g or less were randomized to higher or lower hemoglobin thresholds for transfusion. Data were analyzed between October 2020 and May 2022. Near-infrared spectroscopy monitoring of Csat and Msat. Primary outcomes were changes in Csat, Msat, cFTOE, and mFTOE after transfusion between hemoglobin threshold groups, adjusting for age at transfusion, gestational age, birth weight stratum, and center. Secondary outcome at 22 to 26 months was death or NDI defined as cognitive delay (Bayley Scales of Infant and Toddler Development-III score <85), cerebral palsy with Gross Motor Function Classification System level II or greater, or severe vision or hearing impairment. A total of 179 infants (45 [44.6%] male) with mean (SD) gestational age 25.9 (1.5) weeks were enrolled, and valid data were captured from 101 infants during 237 transfusion events. Transfusion was associated with a significant increase in mean Csat of 4.8% (95% CI, 2.7%-6.9%) in the lower-hemoglobin threshold group compared to 2.7% (95% CI, 1.2%-4.2%) in the higher-hemoglobin threshold group, while mean Msat increased 6.7% (95% CI, 2.4%-11.0%) vs 5.6% (95% CI, 2.7%-8.5%). Mean cFTOE and mFTOE decreased in both groups to a similar extent. There was no significant change in peripheral oxygen saturation (SpO2) in either group (0.2% vs -0.2%). NDI or death occurred in 36 infants (37%). Number of transfusions with mean pretransfusion Csat less than 50% was associated with NDI or death (odds ratio, 2.41; 95% CI, 1.08-5.41; P = .03). In this secondary study of the TOP randomized clinical trial, Csat and Msat were increased after transfusion despite no change in SpO2. Lower pretransfusion Csat may be associated with adverse outcomes, supporting further investigation of targeted tissue saturation monitoring in preterm infants with anemia. ClinicalTrials.gov Identifier: NCT01702805.

Locally contextualized psycho-physiological wellbeing effects of environmental exposures: An experimental-based evidence

Geographically-distributed urban environment contexts affect human psychological wellbeing through the real-time interactions between individuals and their surroundings. Recent field experiments have become particularly interesting in using wearable devices for tracking episodic changes in wellbeing outcomes. However, most research primarily contribute to correlate unconscious physiological arousal with single environmental feature, ignoring the contextualized environment neural psychological effects at the brain level. This paper studies the effects of walking exposures to various urban environment contexts on neural physiological and psychological parameters relevant to mental health in women cohorts. We measure neural physiological parameters using a functional near-infrared spectroscopy (fNIRS) monitoring approach to detect brain activity variability during a journey-based field experiment, and perceived psychological wellbeing outcomes are measured through emotional questionnaires. A group of 10 healthy women walked across dense and diverse urban settings in Guangzhou, China. We have identified the beneficial effects of blue-green spaces and open spaces on psychological wellbeing, as well as their underlying neurophysiological mechanisms that exhibit localized context differentiation. Additional results quantify evidence in support of spatial typology and travel sequence-based uncertainties as underlying channels at work. Our study provide a walking-oriented investigation model of locally contextualized mental health effects, and expand explanatory method for walking mental health. It also suggests the importance of conceptualizing landscape complementarities in planning policies that help to improve the interaction between wellbeing and localized environmental exposures.

Preterm Infants off Positive Pressure Respiratory Support Have a Higher Incidence of Occult Cerebral Hypoxia

To use cerebral near-infrared spectroscopy (NIRS) to quantify occult cerebral hypoxia across respiratory support modes in preterm infants. In this prospective, longitudinal, observational study, infants ≤32weeks gestation underwent serial pulse oximetry (oxygen saturation [SpO2]) and cerebral NIRS monitoring (4-6hours per session) following a standardized recording schedule (daily for 2 weeks, every other day for 2 weeks, then weekly until 35weeks corrected gestational age). Four calculations were made: median cerebral saturation, median cerebral hypoxia burden (proportion of NIRS samples below the hypoxia threshold [<67%]), median systemic saturation, and median systemic hypoxia burden (proportion of SpO2 samples below the desaturation threshold [<85%]). During each recording session, respiratory support mode was noted (room air, low-flow nasal cannula, high-flow nasal cannula, noninvasive positive pressure ventilation, continuous positive airway pressure, and invasive ventilation). There were 1013 recording sessions made from 174 infants with a median length of 6.9hours. Although the systemic (SpO2) hypoxia burden was significantly greater for infants on the highest respiratory support (invasive and noninvasive positive pressure ventilation), the cerebral hypoxia burden was significantly greater during recording sessions made on the lowest respiratory support (8% for room air; 29% for low-flow nasal cannula). Premature infants on the highest levels of respiratory support have less cerebral hypoxia than those on lower respiratory support. These results raise concern about unrecognized cerebral hypoxia during lower acuity periods of neonatal intensive care unit hospitalization and adverse outcomes.

Cerebral near-infrared spectroscopy monitoring to predict periventricular-intraventricular haemorrhage and neurodevelopmental outcomes in preterm infants: a protocol for a systematic review and meta-analysis

IntroductionPeriventricular-intraventricular haemorrhage (PV-IVH) is one of the major cause of mortality and long-term neurodevelopmental sequela in preterm infants born at less than 32 weeks of gestation. Near-infrared spectroscopy (NIRS) monitoring...

Hemodynamic monitoring in the human temporalis muscle using near-infrared spectroscopy

Objective. Altered temporal muscle perfusion is implicated in several painful disorders afflicting orofacial and head regions, including temporomandibular joint dysfunctions, bruxism, and headache. Knowledge about the regulation of blood supply to the temporalis muscle is limited, due to methodological difficulties. The study aimed to test the feasibility of near-infrared spectroscopy (NIRS) monitoring of the human temporal muscle. Approach. Twenty-four healthy subjects were monitored with a 2-channel NIRS: a muscle probe placed over the temporal muscle and a brain probe placed on the forehead. A series of teeth clenching at 25, 50, and 75% of maximum voluntary contraction for 20 s and hyperventilation for 90 s at 20 mmHg of end-tidal CO2 were performed, to elicit hemodynamic changes in muscle and brain, respectively. Main results. In twenty responsive subjects, NIRS signals from both probes were consistently different during both tasks. The absolute change in tissue oxygenation index (ΔTOI) as detected by muscle and brain probes was −9.40 ± 12.28 and 0.29 ± 1.54% during teeth clenching (p < 0.01) at 50% maximum voluntary contraction, while −1.03 ± 2.70 and −5.11 ± 3.81% during hyperventilation (p < 0.01), respectively. Significance. Distinct response patterns were observed from the temporal muscle and prefrontal cortex which proves that this technique is adequate to monitor tissue oxygenation and hemodynamic changes in human temporal muscle. Noninvasive and reliable monitoring of hemodynamics in this muscle will help to extend basic and clinical investigations about the peculiar control of blood flow in head muscles.

Improvement in cerebral oxygen saturation with sinus conversion during off pump coronary artery bypass graft: A case report.

Near-infrared spectroscopy (NIRS) is a noninvasive bedside tool for monitoring regional cerebral oxygen saturation (rSO2). The sinus conversion of atrial fibrillation (AF) was shown to be responsible for increasing rSO2. However, the reason for this improvement has not yet been clearly explained. We report the case of a 73-year-old woman who underwent cardioversion during an off-pump coronary artery bypass under NIRS and live hemodynamic monitoring. Unlike previous studies that failed to control and compare all conditions during procedures, this case showed real-time fluctuating hemodynamic and hematological values, such as hemoglobin (Hgb), central venous pressure (CVP), mean arterial pressure (MAP), cardiac index (CI), left ventricular end-diastolic pressure (LVEDP), and SVO2. The rSO2 increased immediately after cardioversion and decreased during the obtuse marginal (OM) graft and after AF was obtained. However, no other hemodynamic data showed the same or opposite directional changes in the rSO2. Significant instantaneous changes were observed in rSO2 using NIRS after sinus conversion, without obvious hemodynamic alterations in the systemic circulation or other monitoring values.

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.