Neonatal NIRS monitoring: recommendations for data capture and review of analytics

Neonatal somatic oxygenation and perfusion assessment using near-infrared spectroscopy : Part of the series on near-infrared spectroscopy by the European Society of Paediatric Research Special Interest Group "Near-Infrared Spectroscopy"

In this narrative review, we summarize the current knowledge and applications of somatic near-infrared spectroscopy (NIRS), with a focus on intestinal, renal, limb, and multi-site applications in neonates. Assessing somatic oxygenation at various body locations in neonates may aid in the understanding of underlying pathophysiology of organ injury. Considering cerebral autoregulation may be active to protect the brain during systemic circulatory failure, peripheral somatic oxygenation may potentially provide an early indication of neonatal cardiovascular failure and ultimate hypoxemic injury to vital organs including the brain. Certain intestinal oxygenation patterns appear to be associated with the onset and course of necrotizing enterocolitis, whereas impaired renal oxygenation may indicate the onset of acute kidney injury after various types of hypoxic events. Peripheral muscle oxygenation measured at a limb may be particularly effective in the early prediction of shock in neonates. Using multi-site NIRS may complement current approaches and clinical investigations to alert for neonatal tissue hypoxemia, and potentially even guide management. However, somatic NIRS has its inherent limitations in regard to accuracy. Interpretation of organ-specific values can also be challenging. Last, currently there are limited prospective intervention studies, and clinical benefits need to be examined further, after the clarification of critical threshold-values. IMPACT: The assessment of somatic oxygenation using NIRS may contribute to the prediction of specific diseases in hemodynamically challenged neonates. Furthermore, it may give early warning signs for impending cardiovascular failure, and impaired cerebral circulation and oxygenation. We present a comprehensive overview of the literature on applications of NIRS to various somatic areas, with a focus on its potential clinical applicability, including future research directions. This paper will enable prospective standardized studies, and multicenter collaboration to obtain statistical power, likely to advance the field.

Does Cerebral Oxygenation Change during Peripherally Inserted Central Catheterization in Preterm Infants?

OBJECTIVE

 This study aimed to evaluate the effect of peripherally inserted central venous catheterization on cerebral oxygenation by near-infrared spectroscopy in very low birth weight preterm infants.

STUDY DESIGN

 Forty-one preterm infants (gestational age ≤32 weeks and birth weight ≤1,500 g) requiring peripherally inserted central venous catheter were included. Hemodynamic data and cerebral regional oxygen saturation values measured by near-infrared spectroscopy were prospectively collected before (T0) and every 5 minutes for 30 minutes following catheterization. When compared with baseline (T0) values, those values having relative maximum changes in the first 15 minutes and between 15 and 30 minutes were defined as T15 max and T30 max, respectively. Any change of more than a 10% decrease in baseline cerebral rSO2 was considered clinically significant. Additionally, any changes exceeding 20% in heart rate and mean arterial blood pressure values were considered significant. Following catheterization, the time interval to reach the baseline for cerebral regional oxygen saturation was noted.

RESULTS

 Cerebral regional oxygen saturation values at T15 max and T30 max were found to have decreased significantly in 46 and 22% of patients, respectively. A statistically significant difference was observed between these two time periods (p = 0.002); no significant differences in heart rate, mean arterial blood pressure, or cerebral fractional oxygen extraction values at T15 max and T30 max were observed. All patients reached their baseline cerebral regional oxygen saturation in a median of 25 (15-60) minutes.

CONCLUSION

 In very low birth weight preterm infants, monitoring cerebral regional oxygen saturation by near-infrared spectroscopy before and after peripherally inserted central venous catheterization may be useful in clinical practice. The assessment of factors affecting cerebral oxygenation and, in the case of low cerebral oxygenation, implementation of corrective actions before peripherally inserted central catheterization may offer a neuroprotective strategy.

KEY POINTS

· Monitoring cerebral rSO2 by NIRS during PICC line procedure might be useful in preterm infants.. · In this study, a significant decrease in cerebral rSO2 level following catheterization was observed.. · Implementation of corrective actions before PICC line procedure may offer a neuroprotective strategy..

Cerebral and systemic near infrared spectroscopy patterns in preterm infants treated by caffeine

AIM

To investigate the effects of caffeine loading/maintenance administration on near-infrared spectroscopy cerebral, kidney and splanchnic patterns in preterm infants.

METHODS

We conducted a multicentre case-control prospective study in 40 preterm infants (gestational age 29 ± 2 weeks) where each case acted as its own control. A caffeine loading dose of 20 mg/kg and a maintenance dose of 5 mg/kg after 24 h were administered intravenously. Near infrared spectroscopy monitoring parameters were monitored 30 min before, 30 min during and 180 min after caffeine therapy administration.

RESULTS

A significant increase (p < 0.05) in splanchnic regional oxygenation and tissue function and a decrease (p < 0.05) in cerebral tissue function after loading dose was shown. A preferential hemodynamic redistribution from cerebral to splanchnic bloodstream was also observed. After caffeine maintenance dose regional oxygenation did not change in the monitored districts, while tissue function increased in kidney and splanchnic bloodstream.

CONCLUSION

Different caffeine administration modalities affect cerebral/systemic oxygenation status, tissue function and hemodynamic pattern in preterm infants. Future studies correlating near infrared spectroscopy parameters and caffeine therapy are needed to determine the short/long-term effect of caffeine in preterm infants.

Comparison of the Effects of Anaesthesia Methods Used in Caesarean Delivery on Neonatal Cerebral and Renal Oxygenation: A Randomised Controlled Trial

Background: During a newborn's adaptation to extrauterine life, many changes take place that are influenced by various factors. The type of delivery and anaesthesia strategy utilised during labour can modify these adaptive modifications. In this regard, this study was designed to compare the effects of general and spinal anaesthesia on cerebral and renal oxygenation after elective caesarean deliveries. Methods: This randomised controlled study comprised sixty parturient women who were over 18 years old and had a gestational age between 37 and 41 weeks. All participants had an ASA (American Society of Anesthesiologists) classification of II. Neonatal cerebral (CrSO2) and renal (RrSO2) regional oxygen saturations were assessed using near-infrared spectroscopy. Additionally, the 1st-5th min Apgar scores, preductal and postductal peripheral oxygen saturation (SpO2), and perfusion index were recorded in both the general anaesthesia and spinal anaesthesia groups. Results: There was no statistically significant difference between the two groups in terms of CrSO2 or RrSO2 values. The values of CrSO2 and RrSO2 in both groups showed a significant rise from the 10th to the 15th min, respectively. Conclusions: General and spinal anaesthesia techniques used for cesarean delivery have similar effects on neonatal cerebral and renal oxygenation.

Review of measurements and imaging of cytochrome-c-oxidase in humans using near-infrared spectroscopy: an update

This review examines advancements in the measurement and imaging of oxidized cytochrome-c-oxidase (oxCCO) using near-infrared spectroscopy (NIRS) in humans since 2016. A total of 34 published papers were identified, with a focus on both adult and neonate populations. The NIRS-derived oxCCO signal has been demonstrated to correlate with physiological parameters and hemodynamics. New instrumentation, such as systems that allow the imaging of changes of oxCCO with diffuse optical tomography or combine the oxCCO measurement with diffuse correlation spectroscopy measures of blood flow, have advanced the field in the past decade. However, variability in its response across different populations and paradigms and lack of standardization limit its potential as a reliable and valuable indicator of brain health. Future studies should address these issues to fulfill the vision of oxCCO as a clinical biomarker.

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

Importance

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).

Objective

To assess whether HbF and HbA are differently associated with cerebral tissue oxygenation in preterm neonates.

Design, Setting, and Participants

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.

Exposure

Transfusion with A-RBCs or CB-RBCs.

Main Outcomes and Measures

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.

Results

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.

Conclusions and Relevance

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.

Novel approaches to measure transfusion effectiveness

PURPOSE OF REVIEW

This review encompasses different considerations of transfusion effectiveness based upon clinical scenario and transfusion indication. Tissue oxygenation, cerebral metabolic oxygen use, and red blood cell (RBC) survival are important elements of transfusion effectiveness in individuals with acute and chronic transfusion requirements.

RECENT FINDINGS

Noninvasive measures of tissue and cerebral oxygen extraction include near-infrared spectroscopy (NIRS) and specialized MRI sequences. RBC survival timepoints including 24 h posttransfusion recovery, 50% recovery timepoint, and mean potential lifespan may be accurately measured with biotin-labeling of RBC prior to transfusion. Labeling at different cell surface densities allows survival of multiple RBC populations to be determined.

SUMMARY

Although past trials of optimal transfusion thresholds have focused on Hb as a singular marker for transfusion needs, measures of oxygenation (via NIRS or specialized MRI) and RBC survival (via biotin labeling) provide the opportunity to personalize transfusion decisions to individual patient's acute health needs or chronic transfusion goals.

Noninvasive Monitoring Strategies for Bronchopulmonary Dysplasia or Post-Prematurity Respiratory Disease: Current Challenges and Future Prospects

Definitions of bronchopulmonary dysplasia (BPD) or post-prematurity respiratory disease (PPRD) aim to stratify the risk of mortality and morbidity, with an emphasis on long-term respiratory outcomes. There is no univocal classification of BPD due to its complex multifactorial nature and the substantial heterogeneity of clinical presentation. Currently, there is no definitive treatment available for extremely premature very-low-birth-weight infants with BPD, and challenges in finding targeted preventive therapies persist. However, innovative stem cell-based postnatal therapies targeting BPD-free survival are emerging, which are likely to be offered in the first few days of life to high-risk premature infants. Hence, we need easy-to-use noninvasive tools for a standardized, precise, and reliable BPD assessment at a very early stage, to support clinical decision-making and to predict the response to treatment. In this non-systematic review, we present an overview of strategies for monitoring preterm infants with early and evolving BPD-PPRD, and we make some remarks on future prospects, with a focus on near-infrared spectroscopy (NIRS).

Optimizing RBC Transfusion Outcomes in Patients with Acute Illness and in the Chronic Transfusion Setting

Red blood cell (RBC) transfusion is a common clinical intervention used to treat patients with acute and chronic anemia. The decision to transfuse RBCs in the acute setting is based on several factors but current clinical studies informing optimal RBC transfusion decision making (TDM) are largely based upon hemoglobin (Hb) level. In contrast to transfusion in acute settings, chronic RBC transfusion therapy has several different purposes and is associated with distinct transfusion risks such as iron overload and RBC alloimmunization. Consequently, RBC TDM in the chronic setting requires optimizing the survival of transfused RBCs in order to reduce transfusion exposure over the lifespan of an individual and the associated transfusion complications mentioned. This review summarizes the current medical literature addressing optimal RBC-TDM in the acute and chronic transfusion settings and discusses the current gaps in knowledge which need to be prioritized in future national and international research initiatives.

Preterm infants variability in cerebral near-infrared spectroscopy measurements in the first 72-h after birth

BACKGROUND

Cerebral near-infrared spectroscopy is a non-invasive tool used to measure regional cerebral tissue oxygenation (rScO2) initially validated in adult and pediatric populations. Preterm neonates, vulnerable to neurologic injury, are attractive candidates for NIRS monitoring; however, normative data and the brain regions measured by the current technology have not yet been established for this population.

METHODS

This study's aim was to analyze continuous rScO2 readings within the first 6-72 h after birth in 60 neonates without intracerebral hemorrhage born at ≤1250 g and/or ≤30 weeks' gestational age (GA) to better understand the role of head circumference (HC) and brain regions measured.

RESULTS

Using a standardized brain MRI atlas, we determined that rScO2 in infants with smaller HCs likely measures the ventricular spaces. GA is linearly correlated, and HC is non-linearly correlated, with rScO2 readings. For HC, we infer that rScO2 is lower in infants with smaller HCs due to measuring the ventricular spaces, with values increasing in the smallest HCs as the deep cerebral structures are reached.

CONCLUSION

Clinicians should be aware that in preterm infants with small HCs, rScO2 displayed may reflect readings from the ventricular spaces and deep cerebral tissue.

IMPACT

Clinicians should be aware that in preterm infants with small head circumferences, cerebral near-infrared spectroscopy readings of rScO2 displayed may reflect readings from the ventricular spaces and deep cerebral tissue. This highlights the importance of rigorously re-validating technologies before extrapolating them to different populations. Standard rScO2 trajectories should only be established after determining whether the mathematical models used in NIRS equipment are appropriate in premature infants and the brain region(s) NIRS sensors captures in this population, including the influence of both gestational age and head circumference.

Comparison of the SenSmart™ and the INVOS™ neonatal cerebral near-infrared spectrometry devices

Objectives

To determine the correlation and agreement between the SenSmart™ and the INVOS™ devices of neonatal cerebral regional oxygen saturation (CrSO2) measurements using neonatal sensors. The secondary objective was to develop a regression model that predicts CrSO2-INVOS values using CrSO2-SenSmart indices and determine whether the values between the devices are interchangeable.

Methods

A prospective, cross-sectional study was conducted in infants during the first 4 weeks of life. Simultaneous, bilateral CrSO2 was measured using the SenSmart™X100 (CrSO2-SenSmart) or INVOS™ 5100C (CrSO2-INVOS) device in each frontoparietal area for 2 h. Five-minute CrSO2 values were extracted for analysis.

Results

Thirty infants were recruited with 720 pairwise measurements and 26 (84%) were evaluated in the first week of life. Mean gestational age of the preterm and term infants was [30.9 ± 2.8 (n = 14) and 38.8 ± 1.1 (n = 16)] weeks, respectively. Overall CrSO2- was 77.08 ± 9.70% and 71.45 ± 12.74% for the SenSmart and INVOS, respectively (p < 0.001). The correlation coefficient (r) between the CrSO2-SenSmart and INVOS was 0.20 (p < 0.001). The mean difference between the CrSO2-SenSmart and INVOS was 5.63 ± 13.87% with -21.6% to 32.8% limits of agreement. The r and mean difference was 0.39 (p < 0.001) and 8.87 ± 12.58% in preterm infants, and 0.06 (p = 0.27) and 2.79 ± 14.34 in term infants.

Conclusion

The CrSO2-SenSmart tended to read higher than the CrSO2-INVOS device. There was no correlation between the CrSO2-SenSmart and the CrSO2-INVOS in term infants and it was weak in preterms. Due to imprecise agreement, the CrSO2-SenSmart values are not interchangeable with those of the CrSO2-INVOS.

Relationship between cerebral oxygenation, cardiac output, and blood pressure during transitional period in extremely low gestational age neonates

Objective

To describe the relationship between cerebral oxygenation, cardiac output, arterial blood pressure (BP), and cerebral blood flow velocity in extremely low gestational age neonates (ELGANs) during transition.

Methods

This study comprises secondary analyses from a prospective observational study conducted at a tertiary Neonatal Intensive Care Unit. Recruited ELGANs underwent cerebral saturation (CrSO2) monitoring and serial echocardiography during 72 h from birth. Correlative analyses of CrSO2 and cerebral fractional tissue oxygen extraction (CFTOE) with left (LVO) and right ventricular output (RVO), superior vena cava (SVC) flow, middle cerebral artery blood flow mean velocity (MCA.MV), systolic (SBP), diastolic (DBP), and mean (MBP) BP were conducted.

Results

Fifty ELGANs with median (range) gestational age of 25.9 (23.1-27.9) weeks were recruited. Echocardiography was performed sequentially at a median (range) age 5.0 (3.8-6.6), 17.3 (15.4-19.4), 31.0 (27.0-34.1), and 53.7 (49.3-58.3) hours. RVO, LVO, CrSO2, and SBP increased over time but no changes in MBP, DBP, CFTOE, MCA.MV or SVC flow were noted. A weak correlation was identified between CrSO2 and SBP (r2 = 0.11, p = 0.047) and MBP (r2 = 0.12, p = 0.04) at 17.3 (15.4-19.4) hours. No correlation of either CrSO2 or CFTOE with any measures of blood flow was identified.

Conclusion

There is a weak correlation between measures of cardiac output, BP, and MCA.MV with both CrSO2 and CFTOE in ELGANs during transition. Whether this finding suggests intact cerebral autoregulation requires prospective evaluation in a cohort of sick ELGANs.

Comparison of Near-Infrared Spectroscopy-Based Cerebral Autoregulatory Indices in Extremely Low Birth Weight Infants

BACKGROUND

Premature infants are born with immature cerebral autoregulation function and are vulnerable to pressure passive cerebral circulation and subsequent brain injury. Measurements derived from near-infrared spectroscopy (NIRS) have enabled continuous assessment of cerebral vasoreactivity. Although NIRS has enabled a growing field of research, the lack of clear standardization in the field remains problematic. A major limitation of current literature is the absence of a comparative analysis of the different methodologies.

OBJECTIVES

To determine the relationship between NIRS-derived continuous indices of cerebral autoregulation in a cohort of extremely low birth weight (ELBW) infants.

METHODS

Premature infants of birth weight 401-1000 g were studied during the first 72 h of life. The cerebral oximetry index (COx), hemoglobin volume index (HVx), and tissue oxygenation heart rate reactivity index (TOHRx) were simultaneously calculated. The relationship between each of the indices was assessed with Pearson correlation.

RESULTS

Fifty-eight infants with a median gestational age of 25.8 weeks and a median birth weight of 738 g were included. Intraventricular hemorrhage (IVH) was detected in 33% of individuals. COx and HVx demonstrated the highest degree of correlation, although the relationship was moderate at best (r = 0.543, p < 0.001). No correlation was found either between COx and TOHRx (r = 0.318, p < 0.015) or between HVx and TOHRx (r = 0.287, p < 0.029). No significant differences in these relationships were found with respect to IVH and no IVH in subgroup analysis.

CONCLUSIONS

COx, HVx, and TOHRx are not numerically equivalent. Caution must be applied when interpreting or comparing results based on different methodologies for measuring cerebral autoregulation. Uniformity regarding data acquisition and analytical methodology are needed to firmly establish a gold standard for neonatal cerebral autoregulation monitoring.

Development and characterization of transfontanelle photoacoustic imaging system for detection of intracranial hemorrhages and measurement of brain oxygenation: Ex-vivo

We have developed and optimized an imaging system to study and improve the detection of brain hemorrhage and to quantify oxygenation. Since this system is intended to be used for brain imaging in neonates through the skull opening, i.e., fontanelle, we called it, Transfontanelle Photoacoustic Imaging (TFPAI) system. The system is optimized in terms of optical and acoustic designs, thermal safety, and mechanical stability. The lower limit of quantification of TFPAI to detect the location of hemorrhage and its size is evaluated using in-vitro and ex-vivo experiments. The capability of TFPAI in measuring the tissue oxygenation and detection of vasogenic edema due to brain blood barrier disruption are demonstrated. The results obtained from our experimental evaluations strongly suggest the potential utility of TFPAI, as a portable imaging modality in the neonatal intensive care unit. Confirmation of these findings in-vivo could facilitate the translation of this promising technology to the clinic.

Review of recent advances in frequency-domain near-infrared spectroscopy technologies [Invited]

Over the past several decades, near-infrared spectroscopy (NIRS) has become a popular research and clinical tool for non-invasively measuring the oxygenation of biological tissues, with particular emphasis on applications to the human brain. In most cases, NIRS studies are performed using continuous-wave NIRS (CW-NIRS), which can only provide information on relative changes in chromophore concentrations, such as oxygenated and deoxygenated hemoglobin, as well as estimates of tissue oxygen saturation. Another type of NIRS known as frequency-domain NIRS (FD-NIRS) has significant advantages: it can directly measure optical pathlength and thus quantify the scattering and absorption coefficients of sampled tissues and provide direct measurements of absolute chromophore concentrations. This review describes the current status of FD-NIRS technologies, their performance, their advantages, and their limitations as compared to other NIRS methods. Significant landmarks of technological progress include the development of both benchtop and portable/wearable FD-NIRS technologies, sensitive front-end photonic components, and high-frequency phase measurements. Clinical applications of FD-NIRS technologies are discussed to provide context on current applications and needed areas of improvement. The review concludes by providing a roadmap toward the next generation of fully wearable, low-cost FD-NIRS systems.

Advanced Neuromonitoring Modalities on the Horizon: Detection and Management of Acute Brain Injury in Children

Timely detection and monitoring of acute brain injury in children is essential to mitigate causes of injury and prevent secondary insults. Increasing survival in critically ill children has emphasized the importance of neuroprotective management strategies for long-term quality of life. In emergent and critical care settings, traditional neuroimaging modalities, such as computed tomography and magnetic resonance imaging (MRI), remain frontline diagnostic techniques to detect acute brain injury. Although detection of structural and anatomical abnormalities remains crucial, advanced MRI sequences assessing functional alterations in cerebral physiology provide unique diagnostic utility. Head ultrasound has emerged as a portable neuroimaging modality for point-of-care diagnosis via assessments of anatomical and perfusion abnormalities. Application of electroencephalography and near-infrared spectroscopy provides the opportunity for real-time detection and goal-directed management of neurological abnormalities at the bedside. In this review, we describe recent technological advancements in these neurodiagnostic modalities and elaborate on their current and potential utility in the detection and management of acute brain injury.

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.

Post-Exertion Rate of Reperfusion vs Point-by-Point analysis of skeletal tissue near-infrared spectroscopy during repeated fatigue recovery under normoxia and hypoxemia

OBJECTIVE

Near-Infrared Spectroscopy (NIRS) analysis techniques can often be complex to perform and interpret resulting in a barrier for wide-spread clinical use. The traditional Point-by-Point analysis methodology and our Post-Exertion Rate of Reperfusion method were examined during the recovery phases following repeated bouts of physical exertion to determine the physiological processes and information captured by each methodology under normal exertion conditions (FiO₂: 0.210) and when in hypoxic conditions (FiO₂: 0.129).

METHODS

To achieve this, a total of n = 15 participants performed 3 sets of leg extensions to failure at 70 % their maximal effort. A 1-min rest was performed following each set where the Point-by-Point analysis means were calculated at every 6-s time to recovery for a total of 10 mean values. The Post-Exertion Rate of Reperfusion examined the linear slopes for the entire 60-s. The near-infrared spectroscopy device was placed over the vastus lateralis and measure for muscle tissue oxygen saturation, oxygenated hemoglobin, deoxygenated hemoglobin, and total hemoglobin were obtained for both the Point-by-Point and Post-Exertion Rate of Reperfusion analysis.

RESULTS

Post-Exertion Rate of Reperfusion slopes were significantly different between normoxia and hypoxia for muscle tissue oxygen saturation (Normoxia: 0.151-0.171; Hypoxia: 0.068-0.116), oxygenated hemoglobin (Normoxia: 0.127 - 0.134; Hypoxia: 0.045 - 0.076), deoxygenated hemoglobin (Normoxia: -0.142 to -0.152; Hypoxia: -0.054 to -0.100), and total hemoglobin (Normoxia: -0.011 to 0.0250; Hypoxia: -0.009 to 0.024). Point-by-Point analysis identified significant differences between muscle tissue oxygen saturation and oxygenated hemoglobin, but not deoxygenated hemoglobin and total hemoglobin.

CONCLUSION

Point-by-Point analysis and Post-Exertion Rate of Reperfusion can each provide distinctly unique information during exertional recovery. Point-by-Point analysis was ideal for detecting the onset of change in muscle oxygen status. Post-Exertion Rate of Reperfusion identified overall rates of change and was shown to be more sensitive at identifying changes in overall recovery of skeletal tissue reperfusion rates. Point-by-Point analysis and Post-Exertion Rate of Reperfusions may be utilized individually or separately to improve the interpretability of skeletal NIRS metrics within research or clinical settings.

Use of combined cerebral and somatic renal near infrared spectroscopy during noncardiac surgery in children: a proposed algorithm

Cerebral near infrared spectroscopy (NIRS) monitoring has been extensively applied in neonatology and in cardiac surgery, becoming a standard in many pediatric cardiac centers. However, compensatory physiological mechanisms favor cerebral perfusion to the detriment of peripheral tissue oxygenation. Therefore, simultaneous measurement of cerebral and somatic oxygen saturation has been advocated to ease the differential diagnosis between central and peripheral sources of hypoperfusion, which may go undetected by standard monitoring and not mirrored by cerebral NIRS alone. A clinical algorithm already exists in cardiac surgery, aimed to correct intraoperative cerebral oxygen desaturations. A similar algorithm still lacks in noncardiac pediatric surgery. The goal of this paper is to propose a clinical algorithm for the combined use of cerebral and somatic NIRS monitoring during anesthesia in the pediatric population undergoing noncardiac surgery. A panel of experienced pediatric anesthetists developed the algorithm that is based on the clinical experience and intraoperative observations. It aims to lessen the current variability in interpreting NIRS measurement. Multisite NIRS monitoring was achieved applying one pediatric sensor to the forehead for cerebral tissue perfusion reading and a second one to the decumbent lumbar region for recording somatic renal tissue perfusion. The algorithm describes a sequence of acts aimed to identify the putative cause of intraoperative organ tissue desaturation and suggests clinical interventions expected to restore adequate tissue perfusion. It is composed of two arms: the main arm includes patients with an observed decrease in cerebral perfusion (CrO2), the second one includes those with a stable CrSO2 with declining RrSO2. Described also are five clinical cases of infants and neonates in whom pathological alterations of organ perfusion were detected using intraoperative multisite NIRS monitoring, portrayed in the accompanying figures (Annex).

A phase-II clinical trial of targeted cerebral near infrared spectroscopy using standardized treatment guidelines to improve brain oxygenation in preterm infants (BOx-II): A study protocol

BACKGROUND

Mortality and brain injury are common adverse outcomes in infants born <28 weeks. Conventional pulse oximetry may not detect subclinical changes prior to deterioration and fails to detect changes within the brain. Increasing evidence supports the use of cerebral near-infrared spectroscopy (NIRS) in the early care of preterm infants, yet the impact of specific interventions on cerebral oxygenation and the relationship between cerebral hypoxia and brain injury on MRI remain to be determined.

METHODS/DESIGN

100 infants <28 completed weeks of gestation will be recruited for a prospective, multicenter intervention trial. After informed consent, infants will undergo cerebral NIRS monitoring starting within 6 h of birth and continuing through 72 h. Infants with persistent cerebral desaturation will receive interventions following a standard treatment algorithm selected by the provider based on the patient's clinical condition. Providers will record the timing and choice of intervention(s) and term equivalent brain MRI will be performed for survivors. There are three objectives of this study: 1) to identify the relationship between cerebral hypoxia burden and brain injury on term-equivalent MRI. 2) to identify most common interventions after cerebral hypoxia, and 3) to quantify frequency of occult cerebral hypoxia events.

DISCUSSION

There is increasing evidence for the role of early cerebral NIRS monitoring in the neuroprotective care of preterm infants. This phase-II trial will provide essential data to improve the intervention approach, model the effect size of interventions on a wider extent of brain injury, and quantify the discrepancy between measurements of systemic and cerebral hypoxia.

Optical Monitoring in Neonatal Seizures

BACKGROUND

Neonatal seizures remain a significant cause of morbidity and mortality worldwide. The past decade has resulted in substantial progress in seizure detection and understanding the impact seizures have on the developing brain. Optical monitoring such as cerebral near-infrared spectroscopy (NIRS) and broadband NIRS can provide non-invasive continuous real-time monitoring of the changes in brain metabolism and haemodynamics.

AIM

To perform a systematic review of optical biomarkers to identify changes in cerebral haemodynamics and metabolism during the pre-ictal, ictal, and post-ictal phases of neonatal seizures.

METHOD

A systematic search was performed in eight databases. The search combined the three broad categories: (neonates) AND (NIRS) AND (seizures) using the stepwise approach following PRISMA guidance.

RESULTS

Fifteen papers described the haemodynamic and/or metabolic changes observed with NIRS during neonatal seizures. No randomised controlled trials were identified during the search. Studies reported various changes occurring in the pre-ictal, ictal, and post-ictal phases of seizures.

CONCLUSION

Clear changes in cerebral haemodynamics and metabolism were noted during the pre-ictal, ictal, and post-ictal phases of seizures in neonates. Further studies are necessary to determine whether NIRS-based methods can be used at the cot-side to provide clear pathophysiological data in real-time during neonatal seizures.

Aeration strategy at birth does not impact carotid haemodynamics in preterm lambs

BACKGROUND

The impact of different respiratory strategies at birth on the preterm lung is well understood; however, concerns have been raised that lung recruitment may impede cerebral haemodynamics. This study aims to examine the effect of three different ventilation strategies on carotid blood flow, carotid artery oxygen content and carotid oxygen delivery.

METHODS

124-127-day gestation apnoeic intubated preterm lambs studied as part of a larger programme primarily assessing lung injury were randomised to positive pressure ventilation with positive end-expiratory pressure (PEEP) 8 cmH₂O (No-RM; n = 12), sustained inflation (SI; n = 15) or dynamic PEEP strategy (DynPEEP; maximum PEEP 14 or 20 cmH₂O, n = 41) at birth, followed by 90 min of standardised ventilation. Haemodynamic data were continuously recorded, with intermittent arterial blood gas analysis.

RESULTS

Overall carotid blood flow measures were comparable between strategies. Except for mean carotid blood flow that was significantly lower for the SI group compared to the No-RM and DynPEEP groups over the first 3 min (p < 0.0001, mixed effects model). Carotid oxygen content and oxygen delivery were similar between strategies. Maximum PEEP level did not alter cerebral haemodynamic measures.

CONCLUSIONS

Although there were some short-term variations in cerebral haemodynamics between different PEEP strategies and SI, these were not sustained.

IMPACT

Different pressure strategies to facilitate lung aeration at birth in preterm infants have been proposed. There is minimal information on the effect of lung recruitment on cerebral haemodynamics. This is the first study that compares the effect of sustained lung inflation and dynamic and static positive end-expiratory pressure on cerebral haemodynamics. We found that the different ventilation strategies did not alter carotid blood flow, carotid oxygen content or carotid oxygen delivery. This preclinical study provides some reassurance that respiratory strategies designed to focus on lung aeration at birth may not impact cerebral haemodynamics in preterm neonates.

Blended fabric with integrated neural network based on attention mechanism qualitative identification method of near infrared spectroscopy

Near Infrared spectroscopy (NIRS) qualitative analysis technology has shown excellent development potential in the field of blend fabrics. However, the qualitative detection method based on the convolutional neural network (CNN) is difficult to accurately extract the feature of the spectral data, which will lead to missing detection or false detection; when using deep learning to build a qualitative detection model, due to interference of the external environment and other factors, the spectral data collected may have outliers, this means that the knowledge generalization on anomalous testing data, which may have a different distribution of that of the training set, is not trivial, which will also lead to missing detection or false detection. To solve the above problems, this paper proposes a novel qualitative detection neural network by analyzing the near infrared spectral data of blend fabrics. Firstly, we remove the convolutional layer and pooling layer of the CNN, making full use of the feature to enhance the feature representation ability of the model. Secondly, adding the L1 norm of the feature coefficients as a penalty term to the loss function to force those features with high redundancy to become weaker. Thirdly, in order to improve the recognition accuracy of the anomalous spectral data and minimize the model uncertainty, an ensemble machine learning approach utilizing 5 neural networks in parallel is used. To show the superiority of our proposed method, the existing methods are used as competitive methods to compare with our method. Our homemade dataset contains 3482 samples of blend fabrics with 9 different compositions. The results show that the Micro-F1-score, Micro-Specificity, Weight-F1-score, and Weight-Specificity of this method respectively 99.71%, 99.96%, 99.73%, and 99.99%, the results further confirm the method has higher analysis accuracy and stability. In addition, the method proposed in this paper can greatly improve the recognition accuracy of the anomalous spectral data. It has important practical value in the qualitative detection of blend fabrics.

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.

[Hemodynamic monitoring in pediatric anesthesia]

Perioperative mortality and morbidity in childhood essentially depend on the quality of the anesthesia. The Safe Anesthesia for every Tot (SafeTots) initiative takes this into account and has defined normotension, normovolemia and normal heart rate as quality criteria in pediatric anesthesia. Appropriate monitoring of pediatric hemodynamics is necessary to fulfil these criteria. This article provides an overview of currently used methods and techniques for instrumental and non-instrumental cardiovascular monitoring in children. The current study situation, recommendations and guidelines on the application as well as practical aspects of the measurement methods are explained as far as possible. For a better understanding, procedures not routinely used in clinical practice are described in more detail.

Recognition of Attentional States in VR Environment: An fNIRS Study

An improvement in ecological validity is one of the significant challenges for 21st-century neuroscience. At the same time, the study of neurocognitive processes in real-life situations requires good control of all variables relevant to the results. One possible solution that combines the capability of creating realistic experimental scenarios with adequate control of the test environment is virtual reality. Our goal was to develop an integrative research workspace involving a CW-fNIRS and head-mounted-display (HMD) technology dedicated to offline and online cognitive experiments. We designed an experimental study in a repeated-measures model on a group of BCI-naïve participants to verify our assumptions. The procedure included a 3D environment-adapted variant of the classic n-back task (2-back version). Tasks were divided into offline (calibration) and online (feedback) sessions. In both sessions, the signal was recorded during the cognitive task for within-group comparisons of changes in oxy-Hb concentration in the regions of interest (the dorsolateral prefrontal cortex-DLPFC and middle frontal gyrus-MFG). In the online session, the recorded signal changes were translated into real-time feedback. We hypothesized that it would be possible to obtain significantly higher than the level-of-chance threshold classification accuracy for the enhanced attention engagement (2-back task) vs. relaxed state in both conditions. Additionally, we measured participants' subjective experiences of the BCI control in terms of satisfaction. Our results confirmed hypotheses regarding the offline condition. In accordance with the hypotheses, combining fNIRS and HMD technologies enables the effective transfer of experimental cognitive procedures to a controlled VR environment. This opens the new possibility of creating more ecologically valid studies and training procedures.

Current Status and Future Directions of Neuromonitoring With Emerging Technologies in Neonatal Care

Neonatology has experienced a significant reduction in mortality rates of the preterm population and critically ill infants over the last few decades. Now, the emphasis is directed toward improving long-term neurodevelopmental outcomes and quality of life. Brain-focused care has emerged as a necessity. The creation of neonatal neurocritical care units, or Neuro-NICUs, provides strategies to reduce brain injury using standardized clinical protocols, methodologies, and provider education and training. Bedside neuromonitoring has dramatically improved our ability to provide assessment of newborns at high risk. Non-invasive tools, such as continuous electroencephalography (cEEG), amplitude-integrated electroencephalography (aEEG), and near-infrared spectroscopy (NIRS), allow screening for seizures and continuous evaluation of brain function and cerebral oxygenation at the bedside. Extended and combined uses of these techniques, also described as multimodal monitoring, may allow practitioners to better understand the physiology of critically ill neonates. Furthermore, the rapid growth of technology in the Neuro-NICU, along with the increasing use of telemedicine and artificial intelligence with improved data mining techniques and machine learning (ML), has the potential to vastly improve decision-making processes and positively impact outcomes. This article will cover the current applications of neuromonitoring in the Neuro-NICU, recent advances, potential pitfalls, and future perspectives in this field.

Utilizing near infra-red spectroscopy to identify physiologic variations during digital retinal imaging in preterm infants

OBJECTIVE

Evaluate physiologic changes during digital retinal imaging (DRI) using near infra-red spectroscopy (NIRS).

STUDY DESIGN

Prospective observational study of preterm infants undergoing retinopathy of prematurity screening via DRI using wide-field retinal camera. Cardiorespiratory (CR) and NIRS data were collected, trends correlated for changes and coefficient representing "slopes" of outcomes were plotted over time. The p value associated with each slope coefficient was tested to assess for slope differences from time of intervention (time = 0/or no slope).

RESULTS

Thirty-one preterm infants were included in the study. There were no significant changes in pre- and post-slopes for cerebral or mesenteric oxygenation, or CR indices with eye drop administration compared to baseline. DRI resulted in significant increase in post exam slope in cerebral oxygenation, mesenteric oxygenation and respiratory rate.

CONCLUSION

ROP examination using DRI was well tolerated with slight improvements in cerebral and mesenteric perfusion without significant safety concerns.

Vital signs as physiomarkers of neonatal sepsis

Neonatal sepsis accounts for significant morbidity and mortality, particularly among premature infants in the Neonatal Intensive Care Unit. Abnormal vital sign patterns serve as physiomarkers of sepsis and provide early warning of illness before overt clinical decompensation. The systemic inflammatory response to pathogens signals the autonomic nervous system, leading to changes in temperature, respiratory rate, heart rate, and blood pressure. In infants with comorbidities of prematurity, vital sign abnormalities often occur in the absence of infection, which confounds sepsis diagnosis. This review will cover the mechanisms of vital sign changes in neonatal sepsis, including the cholinergic anti-inflammatory pathway mediated by the vagus nerve, which is critical to the host response to infectious and inflammatory insults. We will also review the clinical implications of vital sign changes in neonatal sepsis, including their use in early warning scores and systems to direct clinicians to the bedside of infants with physiologic changes that might be due to sepsis. IMPACT: This manuscript summarizes and reviews the relevant literature on the physiological manifestations of neonatal sepsis and how we monitor and analyze these through vital signs and advanced analytics.

Supplemental Oxygen in the Newborn: Historical Perspective and Current Trends

Oxygen is the final electron acceptor in aerobic respiration, and a lack of oxygen can result in bioenergetic failure and cell death. Thus, administration of supplemental concentrations of oxygen to overcome barriers to tissue oxygen delivery (e.g., heart failure, lung disease, ischemia), can rescue dying cells where cellular oxygen content is low. However, the balance of oxygen delivery and oxygen consumption relies on tightly controlled oxygen gradients and compartmentalized redox potential. While therapeutic oxygen delivery can be life-saving, it can disrupt growth and development, impair bioenergetic function, and induce inflammation. Newborns, and premature newborns especially, have features that confer particular susceptibility to hyperoxic injury due to oxidative stress. In this review, we will describe the unique features of newborn redox physiology and antioxidant defenses, the history of therapeutic oxygen use in this population and its role in disease, and clinical trends in the use of therapeutic oxygen and mitigation of neonatal oxidative injury.

Sparse-Denoising Methods for Extracting Desaturation Transients in Cerebral Oxygenation Signals of Preterm Infants

Preterm infants are at high risk of developing brain injury in the first days of life as a consequence of poor cerebral oxygen delivery. Near-infrared spectroscopy (NIRS) is an established technology developed to monitor regional tissue oxygenation. Detailed waveform analysis of the cerebral NIRS signal could improve the clinical utility of this method in accurately predicting brain injury. Frequent transient cerebral oxygen desaturations are commonly observed in extremely preterm infants, yet their clinical significance remains unclear. The aim of this study was to examine and compare the performance of two distinct approaches in isolating and extracting transient deflections within NIRS signals. We optimized three different simultaneous low-pass filtering and total variation denoising (LPF-TVD) methods and compared their performance with a recently proposed method that uses singular-spectrum analysis and the discrete cosine transform (SSA-DCT). Parameters for the LPF-TVD methods were optimized over a grid search using synthetic NIRS-like signals. The SSA-DCT method was modified with a post-processing procedure to increase sparsity in the extracted components. Our analysis, using a synthetic NIRS-like dataset, showed that a LPF-TVD method outperformed the modified SSA-DCT method: median mean-squared error of 0.97 (95% CI: 0.86 to 1.07) was lower for the LPF-TVD method compared to the modified SSA-DCT method of 1.48 (95% CI: 1.33 to 1.63), P<0.001. The dual low-pass filter and total variation denoising methods are considerably more computational efficient, by 3 to 4 orders of magnitude, than the SSA-DCT method. More research is needed to examine the efficacy of these methods in extracting oxygen desaturation in real NIRS signals.Clinical relevance- Early and precise identification of abnormal brain oxygenation in premature infants would enable clinicians to employ therapeutic strategies that seek to prevent brain injury and long-term morbidity in this vulnerable population.

Near-infrared spectroscopy for perioperative assessment and neonatal interventions

Perioperative applications of near-infrared spectroscopy (NIRS) to monitor regional tissue oxygenation and perfusion in cardiac and noncardiac surgery are of increasing interest in neonatal care. Complex neonatal surgery can impair adequate oxygen delivery and tissue oxygen consumption and increase the risk of neurodevelopmental delay. Coupled with conventional techniques, NIRS monitoring may enable targeted hemodynamic management of the circulation in both cardiac and noncardiac surgical procedures. In this narrative review, we discuss the application of perioperative NIRS in specific neonatal interventions, including surgical intervention for congenital heart defects, definitive closure of the patent ductus arteriosus, neurological and gastrointestinal disorders, and use of extracorporeal membrane oxygenation. We identified areas for future research within disease-specific indications and offer a roadmap to aid in developing evidence-based targeted diagnostic and management strategies in neonates. IMPACT: There is growing recognition that perioperative NIRS monitoring, used in conjunction with conventional monitoring, may provide critical hemodynamic information that either complements clinical impressions or delivers novel physiologic insight into the neonatal circulatory and perfusion pathways.

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.

Similar Hemodynamic Signal Patterns Between Compact NIRS and 52-Channel NIRS During a Verbal Fluency Task

Multichannel near-infrared spectroscopy (NIRS), including 52-channel NIRS (52ch-NIRS), has been used increasingly to capture hemodynamic changes in the brain because of its safety, low cost, portability, and high temporal resolution. However, optode caps might cause pain and motion artifacts if worn for extended periods of time because of the weight of the cables and the pressure of the optodes on the scalp. Recently, a small NIRS apparatus called compact NIRS (cNIRS) has been developed, and uses only a few flexible sensors. Because this device is expected to be more suitable than 52ch-NIRS in the clinical practice for patients with children or psychiatric conditions, we tested whether the two systems were clinically comparable. Specifically, we evaluated the correlation between patterns of hemodynamic changes generated by 52ch-NIRS and cNIRS in the frontopolar region. We scanned 14 healthy adults with 52ch-NIRS and cNIRS, and measured activation patterns of oxygenated-hemoglobin [oxy-Hb] and deoxygenated-hemoglobin [deoxy-Hb] in the frontal pole while they performed a verbal fluency task. We performed detailed temporal domain comparisons of time-course patterns between the two NIRS-based signals. We found that 52ch-NIRS and cNIRS showed significant correlations in [oxy-Hb] and [deoxy-Hb] time-course changes in numerous channels. Our findings indicate that cNIRS and 52ch-NIRS capture similar task-dependent hemodynamic changes due to metabolic demand, which supports the validity of cNIRS measurement techniques. Therefore, this small device has a strong potential for clinical application with infants and children, as well as for use in the rehabilitation or treatment of patients with psychiatric disorders using biofeedback.

Cerebral Blood Flow Monitoring in High-Risk Fetal and Neonatal Populations

Cerebrovascular pressure autoregulation promotes stable cerebral blood flow (CBF) across a range of arterial blood pressures. Cerebral autoregulation (CA) is a developmental process that reaches maturity around term gestation and can be monitored prenatally with both Doppler ultrasound and magnetic resonance imaging (MRI) techniques. Postnatally, there are key advantages and limitations to assessing CA with Doppler ultrasound, MRI, and near-infrared spectroscopy. Here we review these CBF monitoring techniques as well as their application to both fetal and neonatal populations at risk of perturbations in CBF. Specifically, we discuss CBF monitoring in fetuses with intrauterine growth restriction, anemia, congenital heart disease, neonates born preterm and those with hypoxic-ischemic encephalopathy. We conclude the review with insights into the future directions in this field with an emphasis on collaborative science and precision medicine approaches.