Cerebral Oximetry Monitoring in Extremely Preterm Infants

Subgroup analyses and heterogeneity of treatment effects in randomized trials: a primer for the clinician

PURPOSE OF REVIEW

To date, most randomized clinical trials in critical care report neutral overall results. However, research as to whether heterogenous responses underlie these results and give opportunity for personalized care is gaining momentum but has yet to inform clinical practice guidance. Thus, we aim to provide an overview of methodological approaches to estimating heterogeneity of treatment effects in randomized trials and conjecture about future paths to application in patient care.

RECENT FINDINGS

Despite their limitations, traditional subgroup analyses are still the most reported approach. More recent methods based on subphenotyping, risk modeling and effect modeling are still uncommonly embedded in primary reports of clinical trials but have provided useful insights in secondary analyses. However, further simulation studies and subsequent guidelines are needed to ascertain the most efficient and robust manner to validate these results for eventual use in practice.

SUMMARY

There is an increasing interest in approaches that can identify heterogeneity in treatment effects from randomized clinical trials, extending beyond traditional subgroup analyses. While prospective validation in further studies is still needed, these approaches are promising tools for design, interpretation, and implementation of clinical trial results.

Cardiorespiratory interactions during the transitional period in extremely preterm infants: a narrative review

We aimed to review the physiology and evidence behind cardiorespiratory interactions during the transitional circulation of extremely preterm infants with fragile physiology and to propose a framework for future research. Cord clamping strategies have a great impact on initial haemodynamic changes, and appropriate transition can be facilitated by establishing spontaneous ventilation before cord clamping. Mechanical ventilation modifies preterm transitional haemodynamics, with positive pressure ventilation affecting the right and left heart loading conditions. Pulmonary vascular resistances can be minimized by ventilating with optimal lung volumes at functional residual capacity, and other pulmonary vasodilator treatments such as inhaled nitric oxide can be used to improve ventilation/perfusion mismatch. Different cardiovascular drugs can be used to provide support during transition in this population, and it is important to understand both their cardiovascular and respiratory effects, in order to provide adequate support to vulnerable preterm infants and improve outcomes. Current available non-invasive bedside tools, such as near-infrared spectroscopy, targeted neonatal echocardiography, or lung ultrasound offer the opportunity to precisely monitor cardiorespiratory interactions in preterm infants. More research is needed in this field using precision medicine to strengthen the benefits and avoid the harms associated to early neonatal interventions. IMPACT: In extremely preterm infants, haemodynamic and respiratory transitions are deeply interconnected, and their changes have a key impact in the establishment of lung aireation and postnatal circulation. We describe how mechanical ventilation modifies heart loading conditions and pulmonary vascular resistances in preterm patients, and how hemodynamic interventions such as cord clamping strategies or cardiovascular drugs affect the infant respiratory status. Current available non-invasive bedside tools can help monitor cardiorespiratory interactions in preterm infants. We highlight the areas of research in which precision medicine can help strengthen the benefits and avoid the harms associated to early neonatal interventions.

Regional cerebral oxygen saturation variability and brain injury in preterm infants

Objective

To examine whether variation of regional cerebral oxygen saturation (rScO2) within three days after delivery predicts development of brain injury (intraventricular/cerebellar hemorrhage or white matter injury) in preterm infants.

Study design

A prospective study of neonates <32 weeks gestational age with normal cranial ultrasound admitted between 2018 and 2022. All received rScO2 monitoring with near-infrared spectroscopy at admission up to 72 h of life. To assess brain injury a magnetic resonance imaging was performed at term-equivalent age. We assessed the association between rScO2 variability (short-term average real variability, rScO2ARV, and standard deviation, rScO2SD), mean rScO2 (rScO2MEAN), and percentage of time rScO2 spent below 60% (rScO2TIME<60%) during the first 72 h of life and brain injury.

Results

The median [IQR] time from birth to brain imaging was 68 [59-79] days. Of 81 neonates, 49 had some form of brain injury. Compared to neonates without injury, in those with injury rScO2ARV was higher during the first 24 h (P = 0.026); rScO2SD was higher at 24 and 72 h (P = 0.029 and P = 0.030, respectively), rScO2MEAN was lower at 48 h (P = 0.042), and rScO2TIME<60% was longer at 24, 48, and 72 h (P = 0.050, P = 0.041, and P = 0.009, respectively). Similar results were observed in multivariable logistic regression. Although not all results were statistically significant, increased rScO2 variability (rScO2ARV and rScO2SD) and lower mean values of rScO2 were associated with increased likelihood of brain injury.

Conclusions

In preterm infants increased aberration of rScO2 in early postdelivery period was associated with an increased likelihood of brain injury diagnosis at term-equivalent age.

Effect of Cerebral Oximetry-Guided Treatment on Brain Injury in Preterm Infants as Assessed by Magnetic Resonance Imaging at Term Equivalent Age: An Ancillary SafeBoosC-III Study

INTRODUCTION

The SafeBoosC-III trial investigated the effect of cerebral oximetry-guided treatment in the first 72 h after birth on mortality and severe brain injury diagnosed by cranial ultrasound in extremely preterm infants (EPIs). This ancillary study evaluated the effect of cerebral oximetry on global brain injury as assessed by magnetic resonance imaging (MRI) at term equivalent age (TEA).

METHODS

MRI scans were obtained between 36 and 44.9 weeks PMA. The Kidokoro score was independently evaluated by two blinded assessors. The intervention effect was assessed using the nonparametric Wilcoxon rank sum test for median difference and 95% Hodges-Lehmann (HL) confidence intervals (CIs). The intraclass correlation coefficient (ICC) was used to assess the agreement between the assessors.

RESULTS

A total of 210 patients from 8 centers were included, of whom 121 underwent MRI at TEA (75.6% of alive patients): 57 in the cerebral oximetry group and 64 in the usual care group. There was an excellent correlation between the assessors for the Kidokoro score (ICC agreement: 0.93, 95% CI: 0.91-0.95). The results showed no significant differences between the cerebral oximetry group (median 2, interquartile range [IQR]: 1-4) and the usual care group (median 3, IQR: 1-4; median difference -1 to 0, 95% HLCI: -1 to 0; p value 0.1196).

CONCLUSIONS

In EPI, the use of cerebral oximetry-guided treatment did not lead to significant alterations in brain injury, as determined by MRI at TEA. The strong correlation between the assessors highlights the potential of the Kidokoro score in multicenter trials.

Neuromonitoring in neonatal intensive care units-an important need towards individualized neuroprotective care

Neuromonitoring has been widely accepted as an important part in neonatal care. Amplitude-integrated EEG (aEEG) and near-infrared spectroscopy (NIRS) are often mentioned in this context, though being only a part of the fully array of methods and examinations that could be considered neuromonitoring. Within the broad array of medical conditions that could be encountered in a neonatal patient, it is important to be aware of the indications for neuromonitoring and especially which neuromonitoring technique to use best for the individual condition. aEEG is now a widely accepted neuromonitor in neonatology with its value in hypoxic events and seizures only rarely questioned. Other methods like NIRS still have to prove themselves in the future. The SafeBoosC-III trial showed that it still remains difficult for some of these methods to prove their value for the improvement of outcome. Bute future developments such as multimodal neuromonitoring with data integration and artificial intelligence analysis could improve the value of these methods.

First-year outcomes of very low birth weight preterm singleton infants with hypoxemic respiratory failure treated with milrinone and inhaled nitric oxide (iNO) compared to iNO alone: A nationwide retrospective study

BACKGROUND

Inhaled nitric oxide (iNO) has a beneficial effect on hypoxemic respiratory failure. The increased use of concurrent iNO and milrinone was observed. We aimed to report the trends of iNO use in the past 15 years in Taiwan and compare the first-year outcomes of combining iNO and milrinone to the iNO alone in very low birth weight preterm (VLBWP) infants under mechanical ventilation.

METHODS

This nationwide cohort study enrolled preterm singleton infants with birth weight <1500g treated with iNO from 2004 to 2019. Infants were divided into two groups, with a combination of intravenous milrinone (Group 2, n = 166) and without milrinone (Group 1, n = 591). After propensity score matching (PSM), each group's sample size is 124. The primary outcomes were all-cause mortality and the respiratory condition, including ventilator use and duration. The secondary outcomes were preterm morbidities within one year after birth.

RESULTS

After PSM, more infants in Group 2 needed inotropes. The mortality rate was significantly higher in Group 2 than in Group 1 from one month after birth till 1 year of age (55.1% vs. 13.5%) with the adjusted hazard ratio of 4.25 (95%CI = 2.42-7.47, p <0.001). For infants who died before 36 weeks of postmenstrual age (PMA), Group 2 had longer hospital stays compared to Group 1. For infants who survived after 36 weeks PMA, the incidence of moderate and severe bronchopulmonary dysplasia (BPD) was significantly higher in Group 2 than in Group 1. For infants who survived until one year of age, the incidence of pneumonia was significantly higher in Group 2 (28.30%) compared to Group 1 (12.62%) (p = 0.0153).

CONCLUSION

Combined treatment of iNO and milrinone is increasingly applied in VLBWP infants in Taiwan. This retrospective study did not support the benefits of combining iNO and milrinone on one-year survival and BPD prevention. A future prospective study is warranted.

An Update on Pharmacologic Management of Neonatal Hypotension: When, Why, and Which Medication

Anti-hypotensive treatment, which includes dopamine, dobutamine, epinephrine, norepinephrine, milrinone, vasopressin, terlipressin, levosimendan, and glucocorticoids, is a long-established intervention in neonates with arterial hypotension (AH). However, there are still gaps in knowledge and issues that need clarification. The main questions and challenges that neonatologists face relate to the reference ranges of arterial blood pressure in presumably healthy neonates in relation to gestational and postnatal age; the arterial blood pressure level that potentially affects perfusion of critical organs; the incorporation of targeted echocardiography and near-infrared spectroscopy for assessing heart function and cerebral perfusion in clinical practice; the indication, timing, and choice of medication for each individual patient; the limited randomized clinical trials in neonates with sometimes conflicting results; and the sparse data regarding the potential effect of early hypotension or anti-hypotensive medications on long-term neurodevelopment. In this review, after a short review of AH definitions used in neonates and existing data on pathophysiology of AH, we discuss currently available data on pharmacokinetic and hemodynamic effects, as well as the effectiveness and safety of anti-hypotensive medications in neonates. In addition, data on the comparisons between anti-hypotensive medications and current suggestions for the main indications of each medication are discussed.

Acid base and metabolic parameters of the umbilical cord blood and cerebral oxygenation immediately after birth

Objective

Aim was to investigate whether acid-base and metabolic parameters obtained from arterial umbilical cord blood affect cerebral oxygenation after birth in preterm neonates with respiratory support and in term neonates without respiratory support.

Study design

This was a post-hoc analysis of secondary outcome parameters of a prospective observational study including preterm neonates with and term neonates without respiratory support. Non-asphyxiated neonates with cerebral oxygenation measured with near-infrared spectroscopy during the first 15 min and with blood gas analyses from arterial umbilical cord blood were included. Arterial oxygen saturation (SpO2) and heart rate (HR) were monitored with pulse oximetry. Potential correlations were investigated between acid-base and metabolic parameters (pH-value, bicarbonate, base-excess, and lactate) and crSO2/cFTOE 5 min after birth.

Results

Seventy-seven neonates were included: 14 preterm neonates with respiratory support (mean gestational age [GA] 31.4 ± 4.1 weeks; mean birth weight [BW] 1,690 ± 640 g) and 63 term neonates without respiratory support (GA 38.7 ± 0.8 weeks; BW 3,258 ± 443 g). Mean crSO2 5 min after birth was 44.0% ± 24.2% in preterm and 62.2% ± 20.01% in term neonates. Mean cFTOE 5 min after birth was 0.46 ± 0.06 in preterm and 0.27 ± 0.19 in term neonates. In preterm neonates with respiratory support higher lactate was significantly associated with lower crSO2 and SpO2 and tended to be associated with higher cFTOE. In term neonates without respiratory support no significant correlations were found.

Conclusion

In non-asphyxiated preterm neonates with respiratory support, lactate levels were negatively associated with crSO2 and SpO2, whereas in term neonates without respiratory support no associations were observed.

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.

Association between intermittent hypoxemia and neurodevelopmental outcomes in extremely premature infants: A single-center experience

OBJECTIVE

To describe the association between intermittent hypoxemic events (IHEs) and severe neurodevelopmental impairment (SNDI) or death in extremely premature infants.

STUDY DESIGN

Retrospective study of extremely premature infants 230/7-276/7 weeks gestational age (GA) and birthweight (BW) ≤1250 grams (g) admitted to a level IV neonatal intensive care unit (NICU) from 2013 to 2017. IHEs, defined as events with SpO2 ≤ 80 % lasting 10 s to 5 min, were algorithmically identified using data extracted from bedside monitors at 2 s intervals (0.5 Hz). The primary outcome was SNDI at 18-24 months corrected age (CA), defined as a Bayley-III motor, language or cognitive composite score ≤69, or death before discharge while the secondary outcome was SNDI alone. We used mixed-effects regression models to evaluate the relationship between mean daily IHE rate per postnatal week of life for the first 12 weeks and the outcomes, and logistic regression models to assess the association between outcomes and summary measures of hypoxic burden for the entire NICU hospitalization.

RESULTS

The mortality rate was 7 % (18/249) during NICU hospitalization. Of 249 infants born during this time period, IHE and neurodevelopmental outcome data were fully available for 65 infants (mean GA 26 ± 1.4 weeks, mean birth weight (BW) 738 ± 199 g. The outcome of SNDI alone occurred in 34 % (22/65) with a majority demonstrating motor or language delay on the Bayley-III. Although mean daily IHE rate/week was not associated with SNDI or death, total IHE duration was associated with increased odds of SNDI (OR (95 % CI) 1.03 (1.01, 1.05), p = 0.008) in models adjusted for GA.

CONCLUSIONS

In a cohort of extremely premature infants 23-27 weeks GA, each hour of total IHE duration (SpO2 ≤ 80 %) was associated with a 2.7 % (0.7 %, 4.8 %) increase in the odds of SNDI at 18-24 months CA.

The critical role of technologies in neonatal care

Neonatal care has made significant advances in the last few decades. As a result, mortality and morbidity in high-risk infants, such as extremely preterm infants or those infants with birth-related brain injury, has reduced significantly. Many of these advances have been facilitated or delivered through development of medical technologies allowing clinical teams to be better supported with the care they deliver or provide new therapies and diagnostics to improve management. The delivery of neonatal intensive care requires the provision of medical technologies that are easy to use, reliable, accurate and ideally developed for the unique needs of the newborn population. Many technologies have been developed and commercialised following adult trials without ever being studied in neonatal patients despite the unique characteristics of this population. Increasingly, funders and industry are recognising this major challenge which has resulted in initiatives to develop new ideas from concept through to clinical care. This review explores some of the key medical technologies used in neonatal care and the evidence to support their adoption to improve outcomes. A number of devices have yet to realise their full potential and will require further development to optimise and find their ideal target population and clinical benefit. Examples of emerging technologies, which may soon become more widely used, are also discussed. As neonatal care relies more on medical technologies, we need to be aware of the impact on care pathways, especially from a human factors approach, the associated costs and subsequent benefits to patients alongside the supporting evidence.

Detailed statistical analysis plan for a secondary Bayesian analysis of the SafeBoosC-III trial: a multinational, randomised clinical trial assessing treatment guided by cerebral oximetry monitoring versus usual care in extremely preterm infants

BACKGROUND

Extremely preterm infants have a high mortality and morbidity. Here, we present a statistical analysis plan for secondary Bayesian analyses of the pragmatic, sufficiently powered multinational, trial-SafeBoosC III-evaluating the benefits and harms of cerebral oximetry monitoring plus a treatment guideline versus usual care for such infants.

METHODS

The SafeBoosC-III trial is an investigator-initiated, open-label, randomised, multinational, pragmatic, phase III clinical trial with a parallel-group design. The trial randomised 1601 infants, and the frequentist analyses were published in April 2023. The primary outcome is a dichotomous composite outcome of death or severe brain injury. The exploratory outcomes are major neonatal morbidities associated with neurodevelopmental impairment later in life: (1) bronchopulmonary dysplasia; (2) retinopathy of prematurity; (3) late-onset sepsis; (4) necrotising enterocolitis; and (5) number of major neonatal morbidities (count of bronchopulmonary dysplasia, retinopathy of prematurity, and severe brain injury). The primary Bayesian analyses will use non-informed priors including all plausible effects. The models will use a Hamiltonian Monte Carlo sampler with 1 chain, a sampling of 10,000, and at least 25,000 iterations for the burn-in period. In Bayesian statistics, such analyses are referred to as 'posteriors' and will be presented as point estimates with 95% credibility intervals (CrIs), encompassing the most probable results based on the data, model, and priors selected. The results will be presented as probability of any benefit or any harm, Bayes factor, and the probability of clinical important benefit or harm. Two statisticians will analyse the blinded data independently following this protocol.

DISCUSSION

This statistical analysis plan presents a secondary Bayesian analysis of the SafeBoosC-III trial. The analysis and the final manuscript will be carried out and written after we publicise the primary frequentist trial report. Thus, we can interpret the findings from both the frequentists and Bayesian perspective. This approach should provide a better foundation for interpreting of our findings.

TRIAL REGISTRATION

ClinicalTrials.org, NCT03770741. Registered on 10 December 2018.

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

OBJECTIVE

To use cerebral near-infrared spectroscopy (NIRS) to quantify occult cerebral hypoxia across respiratory support modes in preterm infants.

STUDY DESIGN

In this prospective, longitudinal, observational study, infants ≤32 weeks gestation underwent serial pulse oximetry (oxygen saturation [SpO2]) and cerebral NIRS monitoring (4-6 hours per session) following a standardized recording schedule (daily for 2 weeks, every other day for 2 weeks, then weekly until 35 weeks 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).

RESULTS

There were 1013 recording sessions made from 174 infants with a median length of 6.9 hours. 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).

CONCLUSIONS

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.

Cross-sectional association between red blood cell distribution width and regional cerebral tissue oxygen saturation in preterm infants in the first 14 days after birth

Background

Hypoxia can threaten the metabolic functions of different systems in immature neonates, particularly the central nervous system. The red blood cell distribution width (RDW) has recently been reported as a prognostic factor in neurologic diseases. Herein, we examined the correlation between RDW and regional cerebral tissue oxygen saturation (rcSO2).

Methods

This cross-sectional study included 110 preterm infants born at a gestational age (GA) of <32 weeks, or with a birth weight (BW) of <1,500 g at our institution between January and June 2,022. The rcSO2 was monitored using near-infrared spectroscopy, and RDW was extracted from the complete blood count during the first 14 days after birth. RDW and rcSO2 measurements were analyzed using a cross-sectional research method.

Results

We divided the study population into two groups, with a mean rcSO2 value over the first 14 days. Fifty-three preterm had rcSO2 ≥ 55% and 57% < 55%. The 14-days-mean in the study population showing an association of lower rcSO2 values with higher RDW values. Significantly higher RDW values were observed in the low rcSO2 group compared with those in the high rcSO2 group. Threshold effect analysis showed that rcSO2 decreased with RDW values ≥18% (β, -0.03; 95% CI, -0.04 and -0.02; p ≥ 0.0001). After adjusting for potential confounders, an RDW of ≥18% was determined as the predictive cutoff value for preterm infants with low rcSO2 (Model I: OR, 3.31; 95% CI, 1.36-8.06; p = 0.009; and Model II: OR, 3.31; 95% CI, 1.28-8.53; p = 0.013).

Conclusions

An RDW of ≥18% in the first 14 days is associated with rcSO2 of <55% in preterm infants.

The effects of cerebral oximetry in mechanically ventilated newborns: a protocol for the SafeBoosC-IIIv randomised clinical trial

BACKGROUND

The SafeBoosC project aims to test the clinical value of non-invasive cerebral oximetry by near-infrared spectroscopy in newborn infants. The purpose is to establish whether cerebral oximetry can be used to save newborn infants' lives and brains or not. Newborns contribute heavily to total childhood mortality and neonatal brain damage is the cause of a large part of handicaps such as cerebral palsy. The objective of the SafeBoosC-IIIv trial is to evaluate the benefits and harms of cerebral oximetry added to usual care versus usual care in mechanically ventilated newborns.

METHODS/DESIGN

SafeBoosC-IIIv is an investigator-initiated, multinational, randomised, pragmatic phase-III clinical trial. The inclusion criteria will be newborns with a gestational age more than 28 + 0 weeks, postnatal age less than 28 days, predicted to require mechanical ventilation for at least 24 h, and prior informed consent from the parents or deferred consent or absence of opt-out. The exclusion criteria will be no available cerebral oximeter, suspicion of or confirmed brain injury or disorder, or congenital heart disease likely to require surgery. A total of 3000 participants will be randomised in 60 neonatal intensive care units from 16 countries, in a 1:1 allocation ratio to cerebral oximetry versus usual care. Participants in the cerebral oximetry group will undergo cerebral oximetry monitoring during mechanical ventilation in the neonatal intensive care unit for as long as deemed useful by the treating physician or until 28 days of life. The participants in the cerebral oximetry group will be treated according to the SafeBoosC treatment guideline. Participants in the usual care group will not receive cerebral oximetry and will receive usual care. We use two co-primary outcomes: (1) a composite of death from any cause or moderate to severe neurodevelopmental disability at 2 years of corrected age and (2) the non-verbal cognitive score of the Parent Report of Children's Abilities-Revised (PARCA-R) at 2 years of corrected age.

DISCUSSION

There is need for a randomised clinical trial to evaluate cerebral oximetry added to usual care versus usual care in mechanically ventilated newborns.

TRIAL REGISTRATION

The protocol is registered at www.

CLINICALTRIALS

gov (NCT05907317; registered 18 June 2023).

Cerebral oximetry monitoring versus usual care for extremely preterm infants: a study protocol for the 2-year follow-up of the SafeBoosC-III randomised clinical trial

BACKGROUND

In the SafeBoosC-III trial, treatment guided by cerebral oximetry monitoring for the first 72 hours after birth did not reduce the incidence of death or severe brain injury in extremely preterm infants at 36 weeks' postmenstrual age, as compared with usual care. Despite an association between severe brain injury diagnosed in the neonatal period and later neurodevelopmental disability, this relationship is not always strong. The objective of the SafeBoosC-III follow-up study is to assess mortality, neurodevelopmental disability, or any harm in trial participants at 2 years of corrected age. One important challenge is the lack of funding for local costs for a trial-specific assessment.

METHODS

Of the 1601 infants randomised in the SafeBoosC-III trial, 1276 infants were alive at 36 weeks' postmenstrual age and will potentially be available for the 2-year follow-up. Inclusion criteria will be enrollment in a neonatal intensive care unit taking part in the follow-up study and parental consent if required by local regulations. We aim to collect data from routine follow-up programmes between the ages of 18 and 30 months of corrected age. If no routine follow-up has been conducted, we will collect informal assessments from other health care records from the age of at least 12 months. A local co-investigator blinded to group allocation will classify outcomes based on these records. We will supplement this with parental questionnaires including the Parent Report of Children's Abilities-Revised. There will be two co-primary outcomes: the composite of death or moderate or severe neurodevelopmental disability and mean Bayley-III/IV cognitive score. We will use a 3-tier model for prioritisation, based on the quality of data. This approach has been chosen to minimise loss to follow-up assuming that little data is better than no data at all.

DISCUSSION

Follow-up at the age of 2 years is important for intervention trials in the newborn period as only time can show real benefits and harms later in childhood. To decrease the risk of generalisation and data-driven biased conclusions, we present a detailed description of the methodology for the SafeBoosC-III follow-up study. As funding is limited, a pragmatic approach is necessary.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05134116 . Registered on 24 November 2021.

Tissue Oxygenation Changes After Transfusion and Outcomes in Preterm Infants: A Secondary Near-Infrared Spectroscopy Study of the Transfusion of Prematures Randomized Clinical Trial (TOP NIRS)

Importance

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.

Objective

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.

Design, Setting, and Participants

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.

Interventions

Near-infrared spectroscopy monitoring of Csat and Msat.

Main Outcomes and Measures

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.

Results

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).

Conclusions and Relevance

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.

Trial Registration

ClinicalTrials.gov Identifier: NCT01702805.

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.

Machine Learning Detects Intraventricular Haemorrhage in Extremely Preterm Infants

OBJECTIVE

To test the potential utility of applying machine learning methods to regional cerebral (rcSO₂) and peripheral oxygen saturation (SpO₂) signals to detect brain injury in extremely preterm infants.

STUDY DESIGN

A subset of infants enrolled in the Management of Hypotension in Preterm infants (HIP) trial were analysed (n = 46). All eligible infants were <28 weeks' gestational age and had continuous rcSO₂ measurements performed over the first 72 h and cranial ultrasounds performed during the first week after birth. SpO₂ data were available for 32 infants. The rcSO₂ and SpO₂ signals were preprocessed, and prolonged relative desaturations (PRDs; data-driven desaturation in the 2-to-15-min range) were extracted. Numerous quantitative features were extracted from the biosignals before and after the exclusion of the PRDs within the signals. PRDs were also evaluated as a stand-alone feature. A machine learning model was used to detect brain injury (intraventricular haemorrhage-IVH grade II-IV) using a leave-one-out cross-validation approach.

RESULTS

The area under the receiver operating characteristic curve (AUC) for the PRD rcSO₂ was 0.846 (95% CI: 0.720-0.948), outperforming the rcSO₂ threshold approach (AUC 0.593 95% CI 0.399-0.775). Neither the clinical model nor any of the SpO₂ models were significantly associated with brain injury.

CONCLUSION

There was a significant association between the data-driven definition of PRDs in rcSO₂ and brain injury. Automated analysis of PRDs of the cerebral NIRS signal in extremely preterm infants may aid in better prediction of IVH compared with a threshold-based approach. Further investigation of the definition of the extracted PRDs and an understanding of the physiology underlying these events are required.