The SafeBoosC phase II randomised clinical trial: a treatment guideline for targeted near-infrared-derived cerebral tissue oxygenation versus standard treatment in extremely preterm infants

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.

Acute impact of posthemorrhagic ventricular dilatation on cerebral oxygenation in preterm infants with intraventricular haemorrhage

AIM

To assess the effect of ventricular decompression on cerebral oxygenation in preterm neonates with intraventricular haemorrhage (IVH) and posthemorrhagic ventricular dilatation (PHVD) using near-infrared spectroscopy (NIRS).

METHODS

Fifty-three preterm neonates born <34 weeks' gestation between 2013 and 2023 with IVH and subsequent PHVD were prospectively included. Regional cerebral oxygen saturation (rScO2) as well as fractional cerebral tissue oxygen extraction (cFTOE) were analysed 2 weeks before and after ventricular decompression.

RESULTS

Ventricular decompression was performed at 18 ± 6 days of life. Patients with repeated lumbar punctures prior to ventricular drainage showed consistently higher rScO2 and lower cFTOE levels 2 weeks before and after intervention compared to those without. Patients who underwent direct ventricular drainage showed an immediate increase in rScO2 levels on the day of the procedure. In patients who underwent prior lumbar punctures, ventricular decompression did not yield additional acute effects on cerebral oxygenation.

CONCLUSION

Patients who underwent repeated lumbar punctures preceding ventricular drainage consistently maintained higher rScO2 and lower cFTOE levels during the study period. In these patients, ventricular decompression did not further affect cerebral oxygenation, as they already demonstrated improved cerebral hemodynamics, whereas an immediate improvement was observed in those without prior lumbar punctures.

Changes in regional tissue oxygen saturation values during the first week of life in stable preterm infants

OBJECTIVES

Near infrared spectroscopy (NIRS) is a non-invasive method for monitoring regional tissue oxygen saturation (rSO2). The purpose of this study is to investigate the changes that occur in cerebral, splanchnic, and renal rSO2 and fractional tissue oxygen extraction (FTOE) in stable preterm infants in the first week of life.

METHODS

Prospective observational study of infants born 30-34 weeks gestation at NYU Langone Health between November 2017 and November 2018. Cerebral, renal, and splanchnic rSO2 were monitored from 12 to 72 h of life, and at seven days. Subjects were divided into gestational age (GA) cohorts. Average rSO2, splanchnic cerebral oxygen ratio (SCOR), FTOE, and regional intra-subject variability was calculated at each location at five different time intervals: 0-12 h, 12-24 h, 24-48 h, 48-72 h, and one week of life.

RESULTS

Twenty subjects were enrolled. The average cerebral rSO2 ranged from 76.8 to 92.8 %, renal rSO2 from 65.1 to 91.1 %, and splanchnic rSO2 from 36.1 to 76.3 %. The SCOR ranged from 0.45 to 0.94. The strongest correlation between the GA cohorts was in the cerebral region (R2=0.94) and weakest correlation was in the splanchnic region (R2=0.81). The FTOE increased in all three locations over time. Intra-subject variability was lowest in the cerebral region (1.3 % (±1.9)).

CONCLUSIONS

The cerebral region showed the strongest correlation between GA cohorts and lowest intra-subject variability, making it the most suitable for clinical use when monitoring for tissue hypoxia. Further studies are needed to further examine rSO2 in preterm infants.

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.

Predicting the effectiveness of drugs used for treating cardiovascular conditions in newborn infants

BACKGROUND

Cardiovascular support (CVS) treatment failure (TF) is associated with a poor prognosis in preterm infants.

METHODS

Medical charts of infants with a birth weight <1500 g who received either dopamine (Dp) or dobutamine (Db), were reviewed. Treatment response (TR) occurred if blood pressure increased >3rd centile for gestational age or superior vena cava flow was maintained >55 ml/kg/min, with decreased lactate or less negative base excess, without additional CVS. A predictive model of Dp and Db on TR was designed and the impact of TR on survival was analyzed.

RESULTS

Sixty-six infants (median gestational age 27.3 weeks, median birth weight 864 g) received Dp (n = 44) or Db (n = 22). TR occurred in 59% of the cases treated with Dp and 31% with Db, p = 0.04. Machine learning identified a model that correctly labeled Db response in 90% of the cases and Dp response in 61.4%. Sixteen infants died (9% of the TR group, 39% of the TF group; p = 0.004). Brain or gut morbidity-free survival was observed in 52% vs 30% in the TR and TF groups, respectively (p = 0.08).

CONCLUSIONS

New predictive models can anticipate Db but not Dp effectiveness in preterm infants. These algorithms may help the clinicians in the decision-making process.

IMPACT

Failure of cardiovascular support treatment increases the risk of mortality in very low birth weight infants. A predictive model built with machine learning techniques can help anticipate treatment response to dobutamine with high accuracy. Predictive models based on artificial intelligence may guide the clinicians in the decision-making process.

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.

Cerebral oxygen saturation in neonates: a bedside comparison between neonatal and adult NIRS sensors

BACKGROUND

The majority of neonatal NIRS literature recommends target ranges for cerebral saturation (rScO2) based on data using adult sensors. Neonatal sensors are now commonly used in the neonatal intensive care unit (NICU). However, there is limited clinical data correlating these two measurements of cerebral oxygenation.

METHODS

A prospective observational study was conducted in two NICUs between November 2019 and May 2021. An adult sensor was placed on infants undergoing routine cerebral NIRS monitoring with a neonatal sensor. Time-synchronized rScO2 measurements from both sensors, heart rate, and systemic oxygen saturation values were collected over 6 h under varying clinical conditions and compared.

RESULTS

Time-series data from 44 infants demonstrated higher rScO2 measurements with neonatal sensors than with adult sensors; however, the magnitude of the difference varied depending on the absolute value of rScO2 (Adult = 0.63 × Neonatal + 18.2). While there was an approximately 10% difference when adult sensors read 85%, readings were similar when adult sensors read 55%.

CONCLUSION

rScO2 measured by neonatal sensors is typically higher than measured by adult sensors, but the difference is not fixed and is less at the threshold indicative of cerebral hypoxia. Assuming fixed differences between adult and neonatal sensors may lead to overdiagnosis of cerebral hypoxia.

IMPACT

In comparison to adult sensors, neonatal sensors rScO2 readings are consistently higher, but the magnitude of the difference varies depending on the absolute value of rScO2. Marked variability during high and low rScO2 readings was noted, with approximately 10% difference when adult sensors read 85%, but nearly similar (58.8%) readings when adult sensors read 55%. Estimating fixed differences of approximately 10% between adult and neonatal probes may lead to an inaccurate diagnosis of cerebral hypoxia and result in subsequent unnecessary interventions.

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.

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.

The Effect of Continuous PEEP Administration during Surfactant Instillation on Cerebral Hemodynamics in Intubated Preterm Infants: A NIRS Study

OBJECTIVE

There is an ongoing debate about the best and comfortable way to administer surfactant. We hypothesized that uninterrupted respiratory support and continuous PEEP implementation while instilling surfactant via endotracheal tube (ETT) with side port will result in higher regional cerebral tissue oxygenation (rcSO2) and the alterations in cerebral hemodynamics will be minimal.

STUDY DESIGN

Preterm infants who required intubation in the delivery room and/or in the first 24 hours of life with gestational age <32 were enrolled. Patients were intubated either via conventional ETT or ETT with side port (Vygon) with appropriate sizes. Following neonatal intensive care unit admission a near-infrared spectroscopy (NIRS) probe was placed on the forehead and each infant was started to be monitored with NIRS. In conventional ETT group, patients separated from the ventilator while surfactant was instilled. In ETT with side port group, respiratory support was not interrupted during instillation. Heart rate, oxygen saturation, rcSO2, cerebral fractional tissue oxygen extraction (cFTOE), and blood pressures were recorded.

RESULTS

A total of 46 infants were analyzed. Surfactant was instilled with conventional ETT in 23 and ETT with side port in 23 infants. Birth weights (1,037 ± 238 vs. 1,152 ± 277 g) and gestational ages (28 ± 2.3 vs. 29 ± 1.6 weeks) did not differ between groups. During instillation of surfactant, rcSO2 levels [61.5 (49-90) vs. 70 (48-85)] and cFTOE levels 0.28 (0.10-0.44) vs. 0.23 (0.03-0.44)] were similar (p = 0.58 and 0.82, respectively).

CONCLUSION

Interruption of respiratory support during surfactant instillation did not significantly alter the cerebral tissue oxygenation. These results did not support our hypothesis and should be confirmed with further studies.

KEY POINTS

· Monitoring intracerebral oxygenation changes during surfactant administration with NIRS is feasible.. · The surfactant administration method does not significantly alter the cerebral oxygenation.. · Surfactant administration itself rather than the method caused a transient drop in cerebral NIRS readings..

Cerebral Oximetry Monitoring in Extremely Preterm Infants

BACKGROUND

The use of cerebral oximetry monitoring in the care of extremely preterm infants is increasing. However, evidence that its use improves clinical outcomes is lacking.

METHODS

In this randomized, phase 3 trial conducted at 70 sites in 17 countries, we assigned extremely preterm infants (gestational age, <28 weeks), within 6 hours after birth, to receive treatment guided by cerebral oximetry monitoring for the first 72 hours after birth or to receive usual care. The primary outcome was a composite of death or severe brain injury on cerebral ultrasonography at 36 weeks' postmenstrual age. Serious adverse events that were assessed were death, severe brain injury, bronchopulmonary dysplasia, retinopathy of prematurity, necrotizing enterocolitis, and late-onset sepsis.

RESULTS

A total of 1601 infants underwent randomization and 1579 (98.6%) were evaluated for the primary outcome. At 36 weeks' postmenstrual age, death or severe brain injury had occurred in 272 of 772 infants (35.2%) in the cerebral oximetry group, as compared with 274 of 807 infants (34.0%) in the usual-care group (relative risk with cerebral oximetry, 1.03; 95% confidence interval, 0.90 to 1.18; P = 0.64). The incidence of serious adverse events did not differ between the two groups.

CONCLUSIONS

In extremely preterm infants, treatment guided by cerebral oximetry monitoring for the first 72 hours after birth was not associated with a lower incidence of death or severe brain injury at 36 weeks' postmenstrual age than usual care. (Funded by the Elsass Foundation and others; SafeBoosC-III ClinicalTrials.gov number, NCT03770741.).

Cerebral regional tissue Oxygen Saturation to Guide Oxygen Delivery in preterm neonates during immediate transition after birth (COSGOD III): multicentre randomised phase 3 clinical trial

OBJECTIVE

To investigate whether monitoring of cerebral tissue oxygen saturation using near infrared spectroscopy in addition to routine monitoring combined with defined treatment guidelines during immediate transition and resuscitation increases survival without cerebral injury of premature infants compared with standard care alone.

DESIGN

Multicentre, multinational, randomised controlled phase 3 trial.

SETTING

11 tertiary neonatal intensive care units in six countries in Europe and in Canada.

PARTICIPANTS

1121 pregnant women (<32 weeks' gestation) were screened prenatally. The primary outcome was analysed in 607 of 655 randomised preterm neonates: 304 neonates in the near infrared spectroscopy group and 303 in the control group.

INTERVENTION

Preterm neonates were randomly assigned to either standard care (control group) or standard care plus monitoring of cerebral oxygen saturation with a dedicated treatment guideline (near infrared spectroscopy group) during immediate transition (first 15 minutes after birth) and resuscitation.

MAIN OUTCOME MEASURE

The primary outcome, assessed using all cause mortality and serial cerebral ultrasonography, was a composite of survival without cerebral injury. Cerebral injury was defined as any intraventricular haemorrhage or cystic periventricular leukomalacia, or both, at term equivalent age or before discharge.

RESULTS

Cerebral tissue oxygen saturation was similar in both groups. 252 (82.9%) out of 304 neonates (median gestational age 28.9 (interquartile range 26.9-30.6) weeks) in the near infrared spectroscopy group survived without cerebral injury compared with 238 (78.5%) out of 303 neonates (28.6 (26.6-30.6) weeks) in the control group (relative risk 1.06, 95% confidence interval 0.98 to 1.14). 28 neonates died (near infrared spectroscopy group 12 (4.0%) v control group 16 (5.3%): relative risk 0.75 (0.33 to 1.70).

CONCLUSION

Monitoring of cerebral tissue oxygen saturation in combination with dedicated interventions in preterm neonates (<32 weeks' gestation) during immediate transition and resuscitation after birth did not result in substantially higher survival without cerebral injury compared with standard care alone. Survival without cerebral injury increased by 4.3% but was not statistically significant.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03166722.

Near-infrared spectroscopy in the medical management of infants

Near-infrared spectroscopy (NIRS) is a technology that is easy to use and can provide helpful information about organ oxygenation and perfusion by measuring regional tissue oxygen saturation (rSO2) with near-infrared light. The sensors can be placed in different anatomical locations to monitor rSO2 levels in several organs. While NIRS is not without limitations, this equipment is now becoming increasingly integrated into modern healthcare practice with the goal of achieving better outcomes for patients. It can be particularly applicable in the monitoring of pediatric patients because of their size, and especially so in infant patients. Infants are ideal for NIRS monitoring as nearly all of their vital organs lie near the skin surface which near-infrared light penetrates through. In addition, infants are a difficult population to evaluate with traditional invasive monitoring techniques that normally rely on the use of larger catheters and maintaining vascular access. Pediatric clinicians can observe rSO2 values in order to gain insight about tissue perfusion, oxygenation, and the metabolic status of their patients. In this way, NIRS can be used in a non-invasive manner to either continuously or periodically check rSO2. Because of these attributes and capabilities, NIRS can be used in various pediatric inpatient settings and on a variety of patients who require monitoring. The primary objective of this review is to provide pediatric clinicians with a general understanding of how NIRS works, to discuss how it currently is being studied and employed, and how NIRS could be increasingly used in the near future, all with a focus on infant management.

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.

Noninvasive hemoglobin sensing and imaging: optical tools for disease diagnosis

SIGNIFICANCE

Measurement and imaging of hemoglobin oxygenation are used extensively in the detection and diagnosis of disease; however, the applied instruments vary widely in their depth of imaging, spatiotemporal resolution, sensitivity, accuracy, complexity, physical size, and cost. The wide variation in available instrumentation can make it challenging for end users to select the appropriate tools for their application and to understand the relative limitations of different methods.

AIM

We aim to provide a systematic overview of the field of hemoglobin imaging and sensing.

APPROACH

We reviewed the sensing and imaging methods used to analyze hemoglobin oxygenation, including pulse oximetry, spectral reflectance imaging, diffuse optical imaging, spectroscopic optical coherence tomography, photoacoustic imaging, and diffuse correlation spectroscopy.

RESULTS

We compared and contrasted the ability of different methods to determine hemoglobin biomarkers such as oxygenation while considering factors that influence their practical application.

CONCLUSIONS

We highlight key limitations in the current state-of-the-art and make suggestions for routes to advance the clinical use and interpretation of hemoglobin oxygenation information.

Is low cerebral near infrared spectroscopy oximetry associated with neurodevelopment of preterm infants without brain injury?

OBJECTIVES

To evaluate the association between low regional cerebral oxygen saturation (rScO2) and neurodevelopment in preterm infants classified as no brain injury (NBI).

METHODS

We retrospectively reviewed data of rScO2 monitoring during the first 3 days of life of infants with a gestational age (GA)<28 weeks or birth weight (BW)<1,000 g, with and without brain injury (BI). BI was defined as intraventricular haemorrhage, cystic periventricular leukomalacia or cerebellar haemorrhage. Univariate and multivariate analyses were used to study the association of rScO2<55% for more than 10 h in the first 3 days of life (NIRS<55%^>10H) and the 24 months neurodevelopment.

RESULTS

Of the 185 patients who met the inclusion criteria, 31% were classified as BI infants and 69% NBI. BI compared to NBI infants had a significantly lower GA and a higher incidence of complications of prematurity. Mean rScO2 in the first 72 h of life was significantly lower in BI than NBI. NIRS<55%^>10H in NBI patients was negatively associated with neurodevelopmental scores both at the univariate and multivariate analysis (p<0.05). NBI infants with NIRS<55%^>10H were found to have lower systemic oxygenation than their counterparts with rScO2<55% for less than 10 h.

CONCLUSIONS

NIRS<55%^>10H in NBI small preterm infants was found to be an independent predictor of neurodevelopment at 24 months and it was associated with low systemic saturation values.

Hemodynamic management of the micropreemie: When inotropes are not enough

Managing perfusion in the micropreemie is challenging and should be guided by the patho-physiology, gestational and postnatal age of the baby, perinatal history, and the persistence of fetal shunts. The assessment should incorporate bedside tools such as blood pressure, clinical perfusion markers, and functional echocardiography. The multimodal approach to diagnose and identify the cause of hemodynamic compromise paves the way to a targeted approach to treatment. Characterizing the predominant pathophysiologic cause of low cardiac output and impaired cellular metabolism enables a more accurate use of inotropes, vasopressors, and volume support to suit a particular pathophysiologic situation.

The impact of prematurity and associated comorbidities on clinical outcomes in neonates with congenital heart disease

Prematurity is a common risk factor in children, affecting approximately 10% of live births, globally. It is more common in children with critical congenital heart disease (CCHD) and carries important implications in this group of patients. While outcomes have been improving over the years, even late preterm birth is associated with worse outcomes in children born with critical congenital heart disease compared to those without. Infants with both prematurity and CCHD are at particularly high risk for important comorbidities, including: necrotizing enterocolitis, intraventricular hemorrhage, white matter injury, neurodevelopmental anomalies and retinopathy of prematurity. Lesion-specific intensive care management of these infants, interventional and peri-operative management specifically tailored to their needs, and multidisciplinary care all have the potential to improve outcomes in this challenging group.

Early cerebral hypoxia in extremely preterm infants and neurodevelopmental impairment at 2 year of age: A post hoc analysis of the SafeBoosC II trial

BACKGROUND

The SafeBoosC II, randomised clinical trial, showed that the burden of cerebral hypoxia was reduced with the combination of near infrared spectroscopy and a treatment guideline in extremely preterm infants during the first 72 hours after birth. We have previously reported that a high burden of cerebral hypoxia was associated with cerebral haemorrhage and EEG suppression towards the end of the 72-hour intervention period, regardless of allocation. In this study we describe the associations between the burden of cerebral hypoxia and the 2-year outcome.

METHODS

Cerebral oxygenation was continuously monitored from 3 to 72 hours after birth in 166 extremely preterm infants. At 2 years of age 114 of 133 surviving children participated in the follow-up program: medical examination, Bayley II or III test and the parental Ages and Stages Questionnaire. The infants were classified according to the burden of hypoxia: within the first three quartiles (n = 86, low burden) or within in the 4th quartile (n = 28, high burden). All analyses were conducted post hoc.

RESULTS

There were no statistically significant differences between the quantitative assessments of neurodevelopment in the groups of infants with the low burden of cerebral hypoxia versus the group of infants with the high burden of cerebral hypoxia. The infants in the high hypoxia burden group had a higher-though again not statistically significant-rate of cerebral palsy (OR 2.14 (0.33-13.78)) and severe developmental impairment (OR 4.74 (0.74-30.49).

CONCLUSIONS

The burden of cerebral hypoxia was not significantly associated with impaired 2-year neurodevelopmental outcome in this post-hoc analysis of a feasibility trial.

Assessing cerebral blood flow, oxygenation and cytochrome c oxidase stability in preterm infants during the first 3 days after birth

A major concern with preterm birth is the risk of neurodevelopmental disability. Poor cerebral circulation leading to periods of hypoxia is believed to play a significant role in the etiology of preterm brain injury, with the first three days of life considered the period when the brain is most vulnerable. This study focused on monitoring cerebral perfusion and metabolism during the first 72 h after birth in preterm infants weighing less than 1500 g. Brain monitoring was performed by combining hyperspectral near-infrared spectroscopy to assess oxygen saturation and the oxidation state of cytochrome c oxidase (oxCCO), with diffuse correlation spectroscopy to monitor cerebral blood flow (CBF). In seven of eight patients, oxCCO remained independent of CBF, indicating adequate oxygen delivery despite any fluctuations in cerebral hemodynamics. In the remaining infant, a significant correlation between CBF and oxCCO was found during the monitoring periods on days 1 and 3. This infant also had the lowest baseline CBF, suggesting the impact of CBF instabilities on metabolism depends on the level of blood supply to the brain. In summary, this study demonstrated for the first time how continuous perfusion and metabolic monitoring can be achieved, opening the possibility to investigate if CBF/oxCCO monitoring could help identify preterm infants at risk of brain injury.

Three Physiological Components That Influence Regional Cerebral Tissue Oxygen Saturation

Near-infrared spectroscopy (NIRS) measurement of regional cerebral tissue oxygen saturation (rcStO2) has become a topic of high interest in neonatology. Multiple studies have demonstrated that rcStO2 measurements are feasible in the delivery room during immediate transition and resuscitation as well as after admission to the neonatal intensive care unit. Reference ranges for different gestational ages, modes of delivery, and devices have already been published. RcStO2 reflects a mixed tissue saturation, composed of arterial (A), venous (V), and capillary signals, derived from small vessels within the measurement compartment. The A:V signal ratio fluctuates based on changes in oxygen delivery and oxygen consumption, which enables a reliable trend monitoring of the balance between these two parameters. While the increasing research evidence supports its use, the interpretation of the absolute values of and trends in rcStO2 is still challenging, which halts its routine use in the delivery room and at the bedside. To visualize the influencing factors and improve the understanding of rcStO2 values, we have created a flowchart, which focuses on the three major physiological components that affect rcStO2: oxygen content, circulation, and oxygen extraction. Each of these has its defining parameters, which are discussed in detail in each section.

Interventions Triggered During Routine Use of NIRS Cerebral Oxygenation Monitoring in Cardiac Surgical Patients

OBJECTIVE

The purpose of this study was to determine the incidence and types of interventions triggered during a drop of baseline near-infraredspectroscopy (NIRS) values in consecutive cardiac surgical patients.

DESIGN

A single-center, retrospective observational study.

SETTING

A university-affiliated tertiary care center.

PARTICIPANTS

Three thousand three hundred two consecutive cardiac surgical patients from October 2016 to August 2017 Interventions: None.

MEASUREMENTS AND MAIN RESULTS

Of the 1,972 patients who met the inclusion criteria, 576 (29.2%) patients showed NIRS deviation of -20% from baseline. Interventions performed during the drop of baseline NIRS values were documented in 285 (14.4%) patients, with a total of 391 interventions. Three hundred fifteen (80%) interventions were triggered by a deviation in NIRS and concomitant changes in standard monitoring parameters. Seventy-six (20%) interventions were triggered by NIRS deviation alone, with no concomitant pathologic deviation in standard monitoring. A total of 279 (71%) interventions were performed on patients who had no recommendation for NIRS monitoring by current national guidelines. Out of these, 30 (7.7%) interventions (1.3% of all patients) were performed based on NIRS monitoring alone. The higher risk deviation group had longer intensive care unit and hospital lengths of stays (one and 15 days) and postoperative delirium when compared with the no-deviation group (zero and 13 days) Conclusions: The authors' data suggested that most interventions triggered during the drop of baseline values during routine use of NIRS would have also been triggered by the concomitant changes in standard monitoring parameters. Routine use of NIRS for all cardiac surgical patients still is debatable and needs to be evaluated in a large prospective trial.

Vasoactive medications in extremely low gestational age neonates during the first postnatal week

OBJECTIVE

The management of early hypotension in extremely low gestational age neonates (ELGANs) varies greatly between centers. The objective of this study was to provide updated data on the use of vasoactive medications in ELGANs during the first postnatal week.

STUDY DESIGN

We identified ELGANs (22-27 weeks gestational age) cared for at Pediatrix neonatal intensive care units from 2009 to 2018. We evaluated the frequency of exposure to vasoactive medications by gestational age, and compared use of vasoactive medications between two epochs (2009-2013 and 2014-2018).

RESULTS

A total of 10,070/34,234 (29%) ELGANs received ≥1 vasoactive medication. Dopamine was the most frequently used vasoactive medication. The majority (83%) of treated ELGANs initiated therapy on postnatal days 0-1. Overall use of vasoactive medications was slightly lower in 2014-2018 than 2009-2013 (28 vs 31%, p < 0.001).

CONCLUSION

A substantial proportion of ELGANs were exposed to vasoactive medications during the first postnatal week.

The Effect of Antenatal Neuroprotective Magnesium Sulfate Treatment on Cerebral Oxygenation in Preterm Infants

OBJECTIVE

Antenatal magnesium sulfate (MgSO₄) treatment is associated with reduced risk of cerebral palsy in preterm infants. We aimed to investigate whether this treatment leads to any alterations on cerebral hemodynamics which could be detected by near-infrared spectroscopy (NIRS) readings in early postnatal life.

STUDY DESIGN

Infants with gestational ages (GAs) ≤ 32 weeks were divided into two groups regarding their exposure to antenatal neuroprotective MgSO₄ treatment or not. NIRS monitoring was performed to all infants, and readings were recorded for 2 hours each day during the first 3 days of life. The primary aim was to compare regional cerebral oxygen saturation (rcSO₂) and cerebral fractional tissue oxygen extraction (cFTOE) between the groups.

RESULTS

Sixty-six infants were exposed to antenatal MgSO₄, while 64 of them did not. GA and birth weight were significantly lower in the treatment group (p < 0.01). No difference was observed in rcSO₂ and cFTOE levels in the first, second, and the third days of life (p > 0.05). An insignificant reduction in severe intraventricular hemorrhage rates was observed (8 vs. 15%, p = 0.24).

CONCLUSION

We could not demonstrate any effect on cerebral oxygenation of preterm infants in early postnatal life that could be attributed to antenatal neuroprotective MgSO₄ treatment. Future studies are warranted to clarify the exact underlying mechanisms of neuroprotection.

Central data monitoring in the multicentre randomised SafeBoosC-III trial - a pragmatic approach

BACKGROUND

Data monitoring of clinical trials is a tool aimed at reducing the risks of random errors (e.g. clerical errors) and systematic errors, which include misinterpretation, misunderstandings, and fabrication. Traditional 'good clinical practice data monitoring' with on-site monitors increases trial costs and is time consuming for the local investigators. This paper aims to outline our approach of time-effective central data monitoring for the SafeBoosC-III multicentre randomised clinical trial and present the results from the first three central data monitoring meetings.

METHODS

The present approach to central data monitoring was implemented for the SafeBoosC-III trial, a large, pragmatic, multicentre, randomised clinical trial evaluating the benefits and harms of treatment based on cerebral oxygenation monitoring in preterm infants during the first days of life versus monitoring and treatment as usual. We aimed to optimise completeness and quality and to minimise deviations, thereby limiting random and systematic errors. We designed an automated report which was blinded to group allocation, to ease the work of data monitoring. The central data monitoring group first reviewed the data using summary plots only, and thereafter included the results of the multivariate Mahalanobis distance of each centre from the common mean. The decisions of the group were manually added to the reports for dissemination, information, correcting errors, preventing furture errors and documentation.

RESULTS

The first three central monitoring meetings identified 156 entries of interest, decided upon contacting the local investigators for 146 of these, which resulted in correction of 53 entries. Multiple systematic errors and protocol violations were identified, one of these included 103/818 randomised participants. Accordingly, the electronic participant record form (ePRF) was improved to reduce ambiguity.

DISCUSSION

We present a methodology for central data monitoring to optimise quality control and quality development. The initial results included identification of random errors in data entries leading to correction of the ePRF, systematic protocol violations, and potential protocol adherence issues. Central data monitoring may optimise concurrent data completeness and may help timely detection of data deviations due to misunderstandings or fabricated data.

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.

Comparison of basic regional cerebral oxygen saturation values in patients of different ages: a pilot study

Objective

To explore the basic values of regional cerebral oxygen saturation (rSO₂) among different age groups.

Methods

One hundred twenty patients who were scheduled for elective surgery aged 0 to 80 years (American Society of Anesthesiologists [ASA] physical status I or II) or neonates just after birth via cesarean section were enrolled and divided into the following six groups: infant (0 month and ≤12 months), toddler (>1 and ≤3 years old), preschool (>3 and ≤6 years old), school age (>6 and ≤18 years old), adult (>18 and ≤65 years old), and elderly (>65 and ≤80 years old) groups. There were 20 patients in each group.

Results

The basic values of rSO₂ in infant, toddler, preschool, school age, adults, and elderly groups were 70.41% ± 4.66%, 72.43% ± 3.81%, 70.77% ± 3.27%, 70.62% ± 2.20%, 69.76% ± 6.02%, and 62.69% ± 3.14%, respectively. The basic value in the elderly group was lower compared with other five groups. There was no significant difference among infant, toddler, preschool age, school age, and adult groups.

Conclusions

The basic value of rSO₂ in elderly patients is lower. Age is an important factor that affects the underlying value of rSO₂.

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

BACKGROUND

Multiple clinical conditions are associated with cerebral hypoxia/ischaemia and thereby an increased risk of hypoxic-ischaemic brain injury. Cerebral near-infrared spectroscopy monitoring (NIRS) is a tool to monitor brain oxygenation and perfusion, and the clinical uptake of NIRS has expanded over recent years. Specifically, NIRS is used in the neonatal, paediatric, and adult perioperative and intensive care settings. However, the available literature suggests that clinical benefits and harms of cerebral NIRS monitoring are uncertain. As rates of clinically significant hypoxic-ischaemic brain injuries are typically low, it is difficult for randomised clinical trials to capture a sufficiently large number of events to evaluate the clinical effect of cerebral NIRS monitoring, when focusing on specific clinical settings. The aim of this systematic review will be to evaluate the benefits and harms of clinical care with access to cerebral NIRS monitoring versus clinical care without cerebral NIRS monitoring in children and adults across all clinical settings.

METHODS

We will conduct a systematic review with meta-analysis and trial sequential analysis. We will only include randomised clinical trials. The primary outcomes are all-cause mortality, moderate or severe persistent cognitive or neurological deficit, and proportion of participants with one or more serious adverse events. We will search CENTRAL, EMBASE, MEDLINE, and the Science Citation Index Expanded from their inception and onwards. Two reviewers will independently screen all citations, full-text articles, and extract data. The risk of bias will be appraised using the Cochrane risk of bias tool version 2.0. If feasible, we will conduct both random-effects meta-analysis and fixed-effect meta-analysis of outcome data. Additional analysis will be conducted to explore the potential sources of heterogeneity (e.g. risk of bias, clinical setting).

DISCUSSION

As we include trials across multiple clinical settings, there is an increased probability of reaching a sufficient information size. However, heterogeneity between the included trials may impair our ability to interpret results to specific clinical settings. In this situation, we may have to depend on subgroup analyses with inherent increased risks of type I and II errors.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020202986 . This systematic review protocol has been submitted for registration in the International Prospective Register of Systematic Reviews (PROSPERO) (http://www.crd.york.ac.uk/prospero) on the 12th of October 2020 and published on the 12th of November 2020 (registration ID CRD42020202986 ).

Cerebral hemodynamic response to a therapeutic bed for procedural pain management in preterm infants in the NICU: a randomized controlled trial

INTRODUCTION

We developed a novel device, Calmer, that mimics key components of skin-to-skin holding to reduce stress in preterm infants. Our feasibility trial showed that Calmer worked 50% better than no treatment and no differently from our standard of care, facilitated tucking (FT), for reducing pain scores during a heel lance in preterm infants in the neonatal intensive care unit.

OBJECTIVE

We compared the effects of Calmer on regional cerebral hemodynamic activity during a noxious stimulation to FT.

METHODS

During a clinically required heel lance, we measured frontal cortex tissue oxygenation in a subsample of 29 preterm infants (27-33 weeks gestational age) from our larger randomized controlled trial. Infants were randomized to either FT (n = 16) or Calmer treatment (n = 12). The outcome measure, obtained using near-infrared spectroscopy, was a change in the tissue oxygenation index (TSI) across study phases (Baseline, Heel Lance, Recovery; median duration 517 seconds [421-906 seconds]).

RESULTS

No statistically significant differences were found between groups in the median TSI during any of the study phases. In response to the heel lance, 7 infants (27.6%) had a TSI that dipped below the 60% threshold (3 in the Calmer group 25% and 4 in the FT group 25%); none below 50%.

CONCLUSIONS

Infants on Calmer maintained normal regional cerebral oxygen levels (55%-85%) no differently from infants receiving a human touch intervention during blood collection. Parental skin-to-skin holding is one of the most effective strategies to relieve procedural pain in preterm infants. When parents or FT are not available, Calmer shows potential for filling this gap in care.

Cerebral Oxygenation and Autoregulation in Preterm Infants (Early NIRS Study)

OBJECTIVE

To determine if decreased cerebral oxygenation or altered cerebral autoregulation as measured by near-infrared spectroscopy (NIRS) in the first 96 postnatal hours is associated with an increased risk of death or severe neuroradiographic abnormalities in very preterm infants.

STUDY DESIGN

The Early NIRS prospective, multicenter study enrolled very preterm infants with a birth weight of <1250 g from 6 tertiary neonatal intensive care units. Mean arterial blood pressure and cerebral oxygen saturation (Csat) were continuously monitored using a neonatal sensor until 96 hours of age. Moving window correlations between Csat and mean arterial blood pressure determined time periods with altered cerebral autoregulation, and percentiles of correlation were compared between infants with and without the adverse outcome of mortality or severe neuroradiographic abnormalities by early cranial ultrasound.

RESULTS

Of 103 subjects with mean gestational age of 26 weeks, 21 (20%) died or had severe neuroradiographic abnormalities. Infants with adverse outcomes had a lower mean Csat (67 ± 9%) compared with those without adverse outcomes (72 ± 7%; P = .02). A Csat of <50% was identified as a cut-point for identifying infants with adverse outcome (area under the curve, 0.76). Infants with adverse outcomes were more likely to have significant positive or negative correlations between Csat and mean arterial blood pressure, indicating impaired cerebral autoregulation (P = .006).

CONCLUSIONS

Early NIRS monitoring may detect periods of lower cerebral oxygenation and altered cerebral autoregulation, identifying preterm infants at risk for mortality or neuroradiographic injury. An improved understanding of the relationship between altered hemodynamics and cerebral oxygenation may inform future strategies to prevent brain injury.

The Presence of Anemia in Children with Abusive Head Trauma

OBJECTIVES

To evaluate the incidence of anemia in patients with abusive head trauma (AHT), noninflicted traumatic brain injury (TBI), and physical abuse without AHT and the effect of anemia on outcome.

STUDY DESIGN

In a retrospective, single-center cohort study, we included children under the age of 3 years diagnosed with either AHT (n = 75), noninflicted TBI (n = 77), or physical abuse without AHT (n = 60) between January 1, 2014, and December 31, 2016. Neuroimaging was prospectively analyzed by pediatric neuroradiologists. Primary outcome was anemia at hospital presentation. Secondary outcomes included unfavorable outcome at hospital discharge, defined as a Glasgow Outcome Scale between 1 and 3, and intracranial hemorrhage (ICH) volume.

RESULTS

Patients with AHT had a higher rate of anemia on presentation (47.3%) vs noninflicted TBI (15.6%) and physical abuse without AHT (10%) (P < .001). Patients with AHT had larger ICH volumes (33.3 mL [10.1-76.4 mL] vs 1.5 mL [0.6-5.2 mL] ; P < .001) and greater ICH/total brain volume percentages than patients with noninflicted TBI (4.6% [1.4-8.2 %] vs 0.2% [0.1-0.7%]; P < .001). Anemia was associated with AHT (OR, 4.7; 95% CI, 2.2-10.2) and larger ICH/total brain volume percentage (OR, 1.1; 95% CI, 1.1-1.2) in univariate analysis. Unfavorable outcome at hospital discharge was associated with anemia (OR, 4.4; 95% CI, 1.6-12.6) in univariate analysis, but not after controlling for covariates.

CONCLUSIONS

Patients with AHT were more likely to present to the hospital with anemia and increased traumatic ICH volume than patients with noninflicted TBI or physical abuse without AHT. Children with anemia and AHT may be at increased risk for an unfavorable outcome.

Neurocritical care of premature infants

Neurocritical care is an approach of comprehensive care through multidisciplinary coordination and implementation of neuroprotective strategies to reduce the risk of neurologic injury among critically ill patients. Premature infants are at a special risk of sustaining brain injury and having adverse neurodevelopmental outcome. The pathogenesis of "encephalopathy of prematurity" is tightly linked to hemodynamic instability during postnatal transition, immaturity of the cerebral vascular bed and nervous system, and the commonly encountered inflammation in an intensive care setting. Clinical assessment aided by renewed monitoring techniques, together with therapies supported by best available evidence may provide opportunities to salvage these vulnerable brains. Indeed, to promote optimal brain development and to ensure neurodevelopmental intact survival is of imperial priority in the modern care of preterm infants.

Burden of hypoxia and intraventricular haemorrhage in extremely preterm infants

OBJECTIVE

Thresholds of cerebral hypoxia through monitoring of near-infrared spectroscopy tissue oxygenation index (TOI) were used to investigate the relationship between intraventricular haemorrhage (IVH) and indices of hypoxia.

DESIGN

Prospective observational study.

SETTING

A single-centre neonatal intensive care unit.

PATIENTS

Infants <28 weeks' gestation with an umbilical artery catheter.

METHODS

Thresholds of hypoxia were determined from mean values of TOI using sequential Χ² tests and used alongside thresholds from existing literature to calculate percentage of time in hypoxia and burden of hypoxia below each threshold. These indices were then compared between IVH groups.

RESULTS

44 infants were studied for a median of 18.5 (range 6-21) hours in the first 24 hours of life. Sequential Χ² analysis yielded a TOI threshold of 71% to differentiate between IVH (16 infants) and no IVH (28 infants). Percentage of time in hypoxia was significantly higher in infants with IVH than those without, using thresholds of 60%-67%. Burden of hypoxia was significantly higher in infants with IVH than without, using thresholds of 62%-80%. With the threshold of 71%, percentage of time in hypoxia was lower by 12.2% with a 95% CI of (-25.7 to 1.2) (p=0.073), and the burden of hypoxia was lower by 29.2% hour (%h) (95% CI -55.2 to -3.1)%h (p=0.012) in infants without IVH than those with IVH.

CONCLUSIONS

Using defined TOI thresholds, infants with IVH spent higher percentage of time in hypoxia with higher burden of cerebral hypoxia than those without, in the first 24 hours of life.

Pilot test of an online training module on near-infrared spectroscopy monitoring for the randomised clinical trial SafeBoosC-III

BACKGROUND

SafeBoosC-III is an international randomised clinical trial to evaluate the effect of treatment of extremely preterm infants during the first 3 days of life based on cerebral near-infrared spectroscopy (NIRS) monitoring versus treatment and monitoring as usual. To ensure high quality of the trial intervention as well as of patient care, we have developed a multilingual web-based training program to train relevant staff and test their competence. As we enter an under-explored area of e-learning, we have conducted a pilot study on the first of the five modules comprising the web-based training program to test the feasibility of developing such a program for an international trial with limited resources.

METHODS

The module in this study focuses on the principles and practice of NIRS monitoring. The pedagogical idea was to integrate training and certification. One-hundred doctors and nurses from five Neonatal Intensive Care Units across China, Spain and Denmark were invited to participate in the pilot study. Upon completion of the NIRS module, participants were invited to evaluate their experience by completing an online survey. Data from closed-ended questions were analysed using descriptive statistics while data from open-ended questions underwent thematic analysis.

RESULTS

In total, 81 of 100 invited staff members entered the training module and completed the online survey. The median time and the number of questions to pass the module was 15 minutes and seven questions, respectively. Most staff found the academic level of the learning material and quiz appropriate (85% and 93% of all staff members, respectively), as well as agreeing that the module was relevant to prepare them to 'use the NIRS device' (90%). Thematic analysis revealed issues such as a discrepancy between learning material and quiz questions, lack of clarity, and technical issues.

CONCLUSION

We provide evidence of the feasibility of developing a multilingual web-based training program for an international trial, despite challenges such as low budget, language barriers and possibly differences in the clinical training of staff. Exploring the integration of training and certification for international trials, the positive results of this study motivate further developments.

TRIAL REGISTRATION

ClinicalTrial.gov, NCT03770741. Registered 10 December 2018.

Blood Glucose and Lactate Levels and Cerebral Oxygenation in Preterm and Term Neonates-A Systematic Qualitative Review of the Literature

Background: Cerebral oxygenation monitored non-invasively by near-infrared spectroscopy (NIRS) is of increasing interest in neonatal care. Cerebral oxygenation is determined by cerebral oxygen delivery and cerebral oxygen consumption. Oxygen delivery as well as oxygen consumption might be influenced by metabolic parameters like blood glucose and lactate. Objective: The aim of the present systematic qualitative review is therefore to identify and summarize all studies, which describe cerebral oxygenation measured with NIRS and blood glucose and/or blood lactate levels in neonates. Data sources: A systematic search of Ovid Embase and PubMed was performed. Search terms included near-infrared spectroscopy, fractional tissue oxygen extraction, cerebral tissue oxygen saturation, regional cerebral tissue oxygen saturation, oxygenation, term, and preterm neonates, cesarean delivery, transition, after-birth, newborn, vaginal delivery, cesarean delivery, baby, neonatal transition, metabolism, lactate, glucose, and blood glucose level. Study selection/data synthesis: Studies analyzing cerebral oxygenation and blood glucose and/or blood lactate levels in neonates were included. Animal studies, duplicates, or studies in non-English language were excluded. Results: Twenty-five studies were identified that describe blood glucose and/or blood lactate levels as primary or secondary outcome parameters with additional measured cerebral oxygenation by NIRS in neonates. Twelve studies were included with blood glucose measurements: four described an association between blood glucose levels and cerebral oxygenation, two show no association, and six do not report on possible associations. Eighteen studies were included with lactate measurements: one describe an association between lactate levels and cerebral oxygenation, while three show no association and 14 do not report on possible associations. Discussion: The influence of blood glucose and blood lactate levels on the cerebral oxygenation in neonates is still controversial. However, there seems to be an association between cerebral oxygenation and the metabolic parameter blood glucose and lactate, which need further investigation.

Cerebral near-infrared spectroscopy monitoring versus treatment as usual for extremely preterm infants: a protocol for the SafeBoosC randomised clinical phase III trial

BACKGROUND

Cerebral oxygenation monitoring may reduce the risk of death and neurologic complications in extremely preterm infants, but no such effects have yet been demonstrated in preterm infants in sufficiently powered randomised clinical trials. The objective of the SafeBoosC III trial is to investigate the benefits and harms of treatment based on near-infrared spectroscopy (NIRS) monitoring compared with treatment as usual for extremely preterm infants.

METHODS/DESIGN

SafeBoosC III is an investigator-initiated, multinational, randomised, pragmatic phase III clinical trial. Inclusion criteria will be infants born below 28 weeks postmenstrual age and parental informed consent (unless the site is using 'opt-out' or deferred consent). Exclusion criteria will be no parental informed consent (or if 'opt-out' is used, lack of a record that clinical staff have explained the trial and the 'opt-out' consent process to parents and/or a record of the parents' decision to opt-out in the infant's clinical file); decision not to provide full life support; and no possibility to initiate cerebral NIRS oximetry within 6 h after birth. Participants will be randomised 1:1 into either the experimental or control group. Participants in the experimental group will be monitored during the first 72 h of life with a cerebral NIRS oximeter. Cerebral hypoxia will be treated according to an evidence-based treatment guideline. Participants in the control group will not undergo cerebral oxygenation monitoring and will receive treatment as usual. Each participant will be followed up at 36 weeks postmenstrual age. The primary outcome will be a composite of either death or severe brain injury detected on any of the serial cranial ultrasound scans that are routinely performed in these infants up to 36 weeks postmenstrual age. Severe brain injury will be assessed by a person blinded to group allocation. To detect a 22% relative risk difference between the experimental and control group, we intend to randomise a cohort of 1600 infants.

DISCUSSION

Treatment guided by cerebral NIRS oximetry has the potential to decrease the risk of death or survival with severe brain injury in preterm infants. There is an urgent need to assess the clinical effects of NIRS monitoring among preterm neonates.

TRIAL REGISTRATION

ClinicalTrial.gov, NCT03770741. Registered 10 December 2018.

Detailed statistical analysis plan for the SafeBoosC III trial: a multinational randomised clinical trial assessing treatment guided by cerebral oxygenation monitoring versus treatment as usual in extremely preterm infants

BACKGROUND

Infants born extremely preterm are at high risk of dying or suffering from severe brain injuries. Treatment guided by monitoring of cerebral oxygenation may reduce the risk of death and neurologic complications. The SafeBoosC III trial evaluates the effects of treatment guided by cerebral oxygenation monitoring versus treatment as usual. This article describes the detailed statistical analysis plan for the main publication, with the aim to prevent outcome reporting bias and data-driven analyses.

METHODS/DESIGN

The SafeBoosC III trial is an investigator-initiated, randomised, multinational, pragmatic phase III trial with a parallel group structure, designed to investigate the benefits and harms of treatment based on cerebral near-infrared spectroscopy monitoring compared with treatment as usual. Randomisation will be 1:1 stratified for neonatal intensive care unit and gestational age (lower gestational age (< 26 weeks) compared to higher gestational age (≥ 26 weeks)). The primary outcome is a composite of death or severe brain injury at 36 weeks postmenstrual age. Primary analysis will be made on the intention-to-treat population for all outcomes, using mixed-model logistic regression adjusting for stratification variables. In the primary analysis, the twin intra-class correlation coefficient will not be considered. However, we will perform sensitivity analyses to address this. Our simulation study suggests that the inclusion of multiple births is unlikely to significantly affect our assessment of intervention effects, and therefore we have chosen the analysis where the twin intra-class correlation coefficient will not be considered as the primary analysis.

DISCUSSION

In line with the Declaration of Helsinki and the International Conference on Harmonization Good Clinical Practice guidelines, we have developed and published this statistical analysis plan for the SafeBoosC III trial, prior to any data analysis.

TRIAL REGISTRATION

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

A practical approach to cerebral near-infrared spectroscopy (NIRS) directed hemodynamic management in noncardiac pediatric anesthesia

Safeguarding cerebral function is of major importance during pediatric anesthesia. Premature, ex-premature, and full-term neonates can be vulnerable to physiological changes that occur during anesthesia and surgery. Data from studies performed during pediatric cardiac surgery and in neonatal/pediatric intensive care units have shown the benefits of near-infrared spectroscopy (NIRS) monitoring of regional cerebral oxygenation (c-rSO₂ ). However, NIRS monitoring is seldom used during noncardiac pediatric anesthesia. Despite compelling evidence that blood pressure does not reflect end-organ perfusion, it is still regarded as the most important determinant of cerebral perfusion and the most relevant hemodynamic management target parameter by most (pediatric) anesthetists. The principle of NIRS monitoring is not self-explanatory and sometimes seems even counterintuitive, which may explain why many anesthesiologists are reserved regarding its use. The first part of this paper is dedicated to a clinical introduction to NIRS monitoring. Despite scientific efforts, it has not yet been possible to define individual lower limit c-rSO₂ values and it is unlikely this will succeed in the near future. Nonetheless, published treatment algorithms usually specify c-rSO₂ values which may be associated with cerebral hypoxia. Our treatment guideline for maintaining sufficient cerebral oxygenation differs fundamentally from all previously published approaches. We define a baseline c-rSO₂ value, registered in the awake child prior to anesthesia induction, as the lowest acceptable limit during anesthesia and surgery. The cerebral rSO₂ is the single target parameter, while blood pressure, heart rate, P_a CO₂ , and SaO₂ are major parameters that determine the c-rSO2. Cerebral NIRS monitoring, interpreted together with its continuously available contributing parameters, may help avoid potentially harmful episodes of cerebral desaturation in anesthetized pediatric patients.

Regional tissue oxygenation monitoring in the neonatal intensive care unit: evidence for clinical strategies and future directions

Near-infrared spectroscopy (NIRS)-based monitoring of regional tissue oxygenation (rSO₂) is becoming more commonplace in the neonatal intensive care unit (NICU). While increasing evidence supports rSO₂ monitoring, actual standards for applying this noninvasive bedside technique continue to evolve. This review highlights the current strengths and pitfalls surrounding practical NIRS-based monitoring in the neonatal population. The physiologic background of rSO₂ monitoring is discussed, with attention to understanding oxygen delivery/consumption mismatch and its effects on tissue oxygen extraction. The bedside utility of both cerebral and peripheral rSO₂ monitoring in the NICU is then explored from two perspectives: (1) disease/event-specific "responsive" monitoring and (2) "routine," continuous monitoring. Recent evidence incorporating both monitoring approaches is summarized with emphasis on practical applicability in the NICU. Finally, a future paradigm for a broad-based NIRS monitoring strategy is presented, with attention towards improving personalization of neonatal care and ultimately enhancing long-term outcomes.

Reducing Germinal Matrix-Intraventricular Hemorrhage: Perinatal and Delivery Room Factors

Germinal matrix hemorrhage-intraventricular hemorrhage (IVH) is the most common form of brain injury in preterm infants. Although severe IVH has declined over the years, it still affects approximately 6% of infants born before 32 weeks of gestation. Most IVH cases are detectable by the first 24 hours after birth; therefore interventions to prevent IVH should focus on antenatal management for pregnant women and delivery room management. Obstetrical interventions, including antenatal corticosteroids, maternal rather than infant transport, and possibly elective cesarean delivery have been associated with a decreased risk of IVH. Neonatal interventions in the delivery room, including delayed cord clamping or umbilical cord milking, maintaining normothermia, avoiding fluctuations in cerebral blood flow, and optimal ventilation management are associated with a decreased risk of IVH. Multiple clinical trials are under way to further identify IVH risk factors, ability to monitor or predict IVH, and ideally prevent IVH altogether. This discussion will focus on reviewing current obstetric and neonatal management practices and their associations with germinal matrix hemorrhage-IVH.

Cerebral near-infrared spectroscopy in term newborns: reference values and hypoxic-ischemic encephalopathy

Non-invasive measurement of cerebral tissue oxygenation (cStO2) using near-infrared spectroscopy (NIRS) is attracting an increasing attention not only in neonatology. The vast diversity of commercially available NIRS devices makes it difficult to compare in the published clinical studies. This review provides a view on the practical use of NIRS as a tool for cStO2 measurement, its limitations and pitfalls, with a focus on brain dysfunction caused by hypoxic-ischemic encephalopathy. This syndrome of disturbed neurologic function in the earliest days after the birth in the term infants is manifested by difficulty with initiating and maintaining respiration, depression of tone and reflexes, subnormal level of consciousness, and often seizures. This fascinating technology has already proven accurate and has been recommended to use during daily routine tool to evaluate the level of oxygen saturation in brain in intensive care units worldwide.

Low Cerebral Oxygenation in Preterm Infants Is Associated with Adverse Neurodevelopmental Outcome

OBJECTIVE

To assess whether high and low levels of cerebral oxygenation (regional cerebral oxygenation [rScO₂]) in infants born at <32 weeks of gestation were associated with adverse long-term outcome.

STUDY DESIGN

Observational cohort study including preterm infants born at <32 weeks of gestation at the Wilhelmina Children's Hospital, The Netherlands, between April 2006 and April 2013. The rScO₂ was continuously monitored for 72 hours after birth using near-infrared spectroscopy. Outcome was assessed at 15 and 24 months of corrected age by certified investigators. An unfavorable composite outcome was defined as an outcome score below -1 SD or death. Various rScO₂ thresholds were explored.

RESULTS

In total, 734 infants were eligible for analysis, 60 of whom died. Associations with an unfavorable cognitive outcome in multivariable analysis were comparable for time spent with a rScO₂ below 55% and -1.5 SD (according to published reference values), with an OR of 1.4 (CI 1.1-1.7) for 20% of time below either threshold. Results at 15 months were comparable with results at 24 months. Results were not statistically significant for thresholds defining high values of rScO₂. The composite motor outcome was not significantly related to either low or high values or rScO₂.

CONCLUSIONS

Low, but not high, rScO₂ was associated with an unfavorable cognitive outcome. This suggests the use of a threshold of rScO₂ <55% for future clinical studies when using adult near-infrared sensors (rScO₂ <65% for neonatal sensors, approximately).

No neurodevelopmental benefit of cerebral oximetry in the first randomised trial (SafeBoosC II) in preterm infants during the first days of life

AIM

Cerebral hypoxia has been associated with neurodevelopmental impairment. We studied whether reducing cerebral hypoxia in extremely preterm infants during the first 72 hours of life affected neurological outcomes at two years of corrected age.

METHODS

In 2012-2013, the phase II randomised Safeguarding the Brains of our smallest Children trial compared visible cerebral near-infrared spectroscopy (NIRS) monitoring in an intervention group and blinded NIRS monitoring in a control group. Cerebral hypoxia was significantly reduced in the intervention group. We followed up 115 survivors from eight European centres at two years of corrected age, by conducting a medical examination and assessing their neurodevelopment with the Bayley Scales of Infant and Toddler Development, Second or Third Edition, and the parental Ages and Stages Questionnaire (ASQ).

RESULTS

There were no differences between the intervention (n = 65) and control (n = 50) groups with regard to the mean mental developmental index (89.6 ± 19.5 versus 88.4 ± 14.7, p = 0.77), ASQ score (215 ± 58 versus 213 ± 58, p = 0.88) and the number of children with moderate-to-severe neurodevelopmental impairment (10 versus six, p = 0.58).

CONCLUSION

Cerebral NIRS monitoring was not associated with long-term benefits or harm with regard to neurodevelopmental outcome at two years of corrected age.

Postnatal Cerebral Hyperoxia Is Associated with an Increased Risk of Severe Retinopathy of Prematurity

BACKGROUND

High arterial oxygen saturation (SaO2) is associated with the development of retinopathy of prematurity (ROP), but difficult to avoid.

OBJECTIVE

To assess the association between severe ROP and a burden of cerebral and arterial hyperoxia.

METHODS

We retrospectively analyzed 225 preterm infants born ≤30 weeks' gestation. The cerebral oxygen saturation (rcSO2) and SaO2 were measured within the first 96 h after birth. We determined the burden of both cerebral and arterial hyperoxia, which was defined as the percentage of time spent at saturation thresholds exceeding 85 and 90%, respectively. Their association with severe ROP (prethreshold disease type 1) was tested using logistic regression analyses.

RESULTS

Median gestational age (GA) was 28.0 weeks (interquartile range 26.7-29.0) and mean birth weight 1,032 g (±281 SD). Eight infants developed severe ROP. Infants with severe ROP spent more time at cerebral hyperoxic levels than infants without severe ROP (medians 30 vs. 16%). Adjusted for GA, for every 10% increase in burden of cerebral hyperoxia, the OR for developing ROP was 1.50 (95% CI 1.09 - 2.06, p = 0.013). A burden of arterial hyperoxia was not associated with ROP. Infants with severe ROP experienced even less arterial hyperoxia, although not statistically significant.

CONCLUSIONS

Cerebral hyperoxia may be a better early predictor of severe ROP than arterial hyperoxia. Moreover, under strict oxygen management, cerebral hyperoxia in these infants may result from cerebral immaturity rather than a high SaO2. Whether reducing cerebral hyperoxia is feasible and might prevent ROP needs to be further examined.

Neonatal hemodynamics and management of hypotension in newborns

Hemodynamic instability is frequent in high-risk infants admitted to neonatal intensive care units. However, monitoring and treatment strategies of those conditions might show variations among the units. Different factors can compromise hemodynamic status in preterm/ term infants. Treatment options mostly include volume replacement, inotropes and/or vasopressors (dopamine, dobutamine, epinephrine and milrinone) and hydrocortisone. In general, these treatments are driven by predetermined protocols, which are not patient-based. According to the current knowledge, a physiology-driven approach that takes the individual characteristics of the newborn into consideration is accepted to be more suitable. In neonatal hemodynamics, important determinants are cardiac output, systemic vascular resistance, blood pressure, regional tissue perfusion and oxygenation. The novel technological methods, "targeted neonatal echocardiography" and "near-infrared spectroscopy" can help to delineate the underlying pathophysiology better, when added to the clinical assessment. In this review, strategies for the assessment of neonatal hemodynamics, as well as etiology, monitoring, and treatment of hemodynamic instability in preterm and term infants are presented.

Bradycardias are associated with more severe effects on cerebral oxygenation in very preterm infants than in late preterm infants

BACKGROUND

Commonly the magnitude and frequency of bradycardia is underestimated in the neonatal unit due to the long averaging time used in bedside oximeters. We aimed to assess the frequency and severity of bradycardia in preterm infants using the lowest averaging time (2 s) available on a clinical oximeter, compared with bradycardia detected using electrocardiogram (ECG), and whether bradycardia severity and postmenstrual age affected cerebral oxygenation.

METHODS

Preterm infants (10 M/9F) were studied longitudinally at 26-31 (very preterm) and 32-38 weeks (late preterm) postmenstrual age. Heart rate falls calculated from ECG were used to determine mild or moderate/severe (MS) bradycardias. Cerebral tissue oxygenation index (TOI, %) was recorded and fractional tissue oxygen extraction (FTOE) calculated.

RESULTS

Of the 615 bradycardias scored using ECG criteria, 10% were not detected by oximetry. TOI falls associated with bradycardias were greater for MS bradycardias compared with Mild for both groups (p < 0.001 for both). The FTOE associated with MS bradycardias was higher for the very preterm compared with the late preterm group (p < 0.001). In very preterm infants 61% of MS and 35% Mild bradycardias were associated with TOI nadirs below 55%.

CONCLUSION

Even the most sensitive oximeter setting underestimates bradycardias. The cerebral effect from bradycardias in very preterm infants is more severe than in late preterm infants. Even the mild bradycardias are associated with falls in cerebral oxygenation. Routine NIRS monitoring of cerebral oxygenation in NICUs may increase staff awareness for interventions to reduce the repetitive falls in cerebral oxygenation in preterm infants.