Feed-related Splanchnic Oxygenation in Preterm Infants With Abnormal Antenatal Doppler Developing Gut Complications

Biobehavioral Efficacy of the Elevated Side-Lying Position for Feeding Preterm Infants: Study Protocol

AIM

Present a study protocol investigating the biobehavioral efficacy of side-lying vs. supine positions on physiologic and behavioural responses of preterm infants during their transition from tube to full oral feeding, and identify associated infant characteristics.

DESIGN

Within-subject cross-over design.

METHODS

Sixty preterm infants born at ≤35 weeks gestational age (GA) from a level 3 NICU are observed during their transition to full oral feeding. Each undergoes two feedings within 24 h: One in the supine position and one in the side-lying position. Continuous physiologic and video data are collected 30 min before and after feeding. Physiologic measures include heart rate, respiratory rate, oxygen saturation, and autonomic nervous system regulation (heart rate variability and splanchnic-cerebral oxygen ratio). Behavioural responses are assessed via microanalysis of the sucking and breathing waveforms and videotaped feedings (Suck-breathe coordination and Early Feeding Skills assessment tool). Data are analysed using linear mixed-effects models. IRB was obtained in September 2021, with funding awarded by the National Institute of Nursing Research in July 2021.

CONCLUSION

This study will enhance our understanding of the effects of the side-lying position on preterm infant feeding, providing guidance for its clinical use as a feeding strategy.

IMPLICATIONS

Provides vital knowledge to guide evidence-based practices in enhancing oral feeding in preterm infants and inform future pivotal efficacy trials.

IMPACT

If effective, this intervention could significantly enhance the management of feeding challenges in preterm infants across neonatal care settings.

REPORTING METHOD

Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) 2013.

PATIENT OR PUBLIC CONTRIBUTION

While direct parent involvement was not documented in our protocol, informal feedback on data collection procedures from parents was incorporated. Additionally, extensive engagement with healthcare professionals during study design addressed patient safety, logistical challenges, and ethical standards in NICU settings.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT04942106; registered on 28 June 2021. Available at: https://clinicaltrials.gov/ct2/show/NCT04942106.

Initiation of enteral feeding as per current protocol (at 24 h) versus as per clinical status (from 6 h onwards) in neonates born with antenatal reversed end diastolic flow (REDF) in the umbilical artery Doppler: a pilot randomized controlled trial

OBJECTIVE

To compare the effects of initiating feeds at 24 h versus at 6 h in neonates with reversed end-diastolic flow (REDF) and determine the incidence of feed intolerance (FI) and necrotizing enterocolitis (NEC).

DESIGN

Pilot randomized controlled trial.

METHODS

Neonates with REDF (n = 52) were randomized to start feeds at 6 h (n = 26) or 24 h (n = 26) to assess FI, NEC, time to full feeds, sepsis, mortality, weight and gestation at discharge, and hospital stay.

RESULTS

FI was observed in 14 (54%) neonates in 6 h group and 17 (65%) in 24 h group, with comparable NEC rates. Neonates in the 6 h group achieved full feeds faster (8 vs. 11 days) and had shorter hospital stay (17 vs. 32 days). Death and sepsis rates were similar.

CONCLUSIONS

Feed initiation at 6 h in REDF neonates did not increase the risk of FI or NEC.

TRIAL REGISTRATION

Clinical trial registry of India (CTRI/2023/02/050025); 23/02/2023.

Regional tissue oxygen saturation during minimal enteral feeding is associated with the subsequent feeding intolerance in very preterm infants

Feeding intolerance (FI) is a common clinical problem in very preterm infants (VPIs) and it increases the risk for adverse outcomes. The value of regional tissue oxygen saturation in predicting FI remains unclear. A total of 57 VPIs were involved in this study, and the regional splanchnic and cerebral tissue oxygen saturation during minimal enteral feeding in the first 3 days after birth was monitored and analyzed. Compared with the feeding tolerance (FT) group, the FI group had a smaller gestational age, lower birth weight, and higher rate of maternal hypertensive disorders in pregnancy. Even more, the FI group had lower regional splanchnic tissue oxygen saturation and lower splanchnic-cerebral oxygenation ratio (SCOR) at the 1st hour and 2nd hour after feeding on the 3rd postnatal day than the FT group (P < 0.05). Multivariate logistic regression analysis showed that increased gestational age and elevated SCOR at the 2nd hour after feeding on the 3rd postnatal day reduced the risk for FI (P < 0.05). The areas under the curve (AUCs) of gestational age, SCOR at the 2nd hour after feeding on the 3rd postnatal day and their combination in predicting FT were 0.745 (95%CI 0.616 ~ 0.874), 0.756 (95%CI 0.628 ~ 0.883) and 0.820 (95%CI 0.710 ~ 0.929), respectively.

The effects of nutrition on mesenteric oxygenation among neonates with neonatal encephalopathy: a randomized clinical trial

BACKGROUND

We aimed to evaluate the effects of minimal enteral nutrition (MEN) on mesenteric blood flow and oxygenation with Doppler USG and Near Infrared Spectroscopy (NIRS) during therapeutic hypothermia (TH) in babies with HIE.

METHODS

This prospective, randomized-controlled study was composed of infants receiving MEN (study group, n = 30) and infants who were not fed (control group, n = 30) during hypothermia. Infants were monitored continuously with NIRS and mesenteric blood flow velocities were measured with Doppler USG before and after feeding.

RESULTS

The mean gestational age and birth weight for the study and control group were 38.73 ± 1.5-39.09 ± 1.02 weeks and 3076 ± 280.4-3295 ± 391 grams, respectively. Time to reach full enteral nutrition and hospital stay were significantly shorter in the study group (p = 0.049, p = 0.016). Infants in the study group experienced less feeding intolerance (p = 0.006). No infant developed necrotizing enterocolitis (NEC) in both groups. No difference was determined in pre- and post-feeding cerebral rSO2 measurements during TH and normothermia. Mesenteric rSO2, CSOR, and mesenteric blood flow measurements in the study group during normothermia were significantly increased, respectively (p = 0.03, p < 0.01, p < 0.01).

CONCLUSION

In our study, we observed that MEN during TH does not lead to a significant change in cerebral and mesenteric oxygenation. Although we did not observe an increase in blood flow and oxygenation, the absence of NEC and a lower incidence of feeding intolerance in the study group may suggest that feeding during TH is safe and feasible.

IMPACT

MEN during TH treatment does not lead to a significant change in cerebral and mesenteric oxygenation. This is the first study evaluating the effects of MEN on mesenteric oxygenation and blood flow velocities in infants with hypoxic-ischemic encephalopathy during TH with Doppler USG and NIRS, concomitantly. MEN during TH may be safe and feasible.

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.

Improving growth in preterm infants through nutrition: a practical overview

The primary purpose of this practical overview is to provide a practical update on appropriate nutritional strategies to improve growth in preterm infants. Current recommendations for improving preterm growth concern both macronutrients and micronutrients, with tailored nutrition since the first days of life, particularly when fetal growth restriction has been reported. Human milk is undoubtedly the best nutrition for all newborns, but, in some populations, if not adequately fortified, it does not adequately support their growth. In all preterms, growth should be correctly monitored weekly to intercept a negative trend of growth and implement nutritional strategies to avoid growth restriction. Similarly, growth should be accurately supported and monitored after discharge to improve long-term health consequences.

Nutritional Strategies for Preterm Neonates and Preterm Neonates Undergoing Surgery: New Insights for Practice and Wrong Beliefs to Uproot

The nutrition of preterm infants remains contaminated by wrong beliefs that reflect inexactitudes and perpetuate old practices. In this narrative review, we report current evidence in preterm neonates and in preterm neonates undergoing surgery. Convictions that necrotizing enterocolitis is reduced by the delay in introducing enteral feeding, a slow advancement in enteral feeds, and the systematic control of residual gastric volumes, should be abandoned. On the contrary, these practices prolong the time to reach full enteral feeding. The length of parenteral nutrition should be as short as possible to reduce the infectious risk. Intrauterine growth restriction, hemodynamic and respiratory instability, and patent ductus arteriosus should be considered in advancing enteral feeds, but they must not translate into prolonged fasting, which can be equally dangerous. Clinicians should also keep in mind the risk of refeeding syndrome in case of high amino acid intake and inadequate electrolyte supply, closely monitoring them. Conversely, when preterm infants undergo surgery, nutritional strategies are still based on retrospective studies and opinions rather than on randomized controlled trials. Finally, this review also highlights how the use of adequately fortified human milk is strongly recommended, as it offers unique benefits for immune and gastrointestinal health and neurodevelopmental outcomes.

The effect of drip versus intermittent feeding on splanchnic oxygenation in preterm infants with intrauterine growth restriction: a prospective randomized trial

The main purpose of this study was to evaluate the impact of drip versus intermittent feeding on splanchnic oxygenation in preterm infants with intrauterine growth restriction. The second objective was to assess the relationship between fetal splanchnic circulation parameters and splanchnic oxygenation during the first week of life. A single-center, prospective, randomized study with 51 fetuses/infants was conducted. Fetal Doppler measurements including umbilical artery, middle cerebral artery, and superior mesenteric artery (SMA) were recorded in IUGR fetuses. After preterm delivery, the infants were randomly assigned to one of two feeding modalities: drip (3-h continuous) or intermittent (bolus in 10 min). Continuous regional splanchnic saturation (rSO₂S) monitoring was carried out during the first week of life, simultaneously with continuous oxygen arterial saturation (SaO₂) monitoring, and the infants' fractional oxygen extractions (FOE) were calculated. These parameters were evaluated as means on a daily basis for the first week of life, as well as pre-prandial and post-prandial measurements on the seventh day. Fetal Doppler flow velocimetry disturbances were present in 72.5% of the study cohort. The drip (26 infants) and intermittent (25 infants) groups were similar in demographic and clinical characteristics, as well as the prevalence of feeding intolerance and necrotizing enterocolitis. During the first week of life, there was no difference in daily mean rSO₂S and FOE values between the drip and intermittent groups, whereas unfed infants had mostly lower rSO₂S values. Pre-prandial and post-prandial rSO₂S values remained stable in both groups. Also, no association was detected between fetal splanchnic circulation parameters and neonatal splanchnic oxygenation. RSO₂S values were strongly correlated to gestational age and birth weight. During the whole week, except for the first 2 days, infants with umbilical catheters had significantly lower rSO₂S values than infants without.  Conclusion: Our data suggest that the key factor in splanchnic oxygenation is feeding, not the feeding modality. In addition, the umbilical vein catheter had a negative impact on splanchnic oxygenation.  Clinical Trial Registration: The Effect of Neonatal Feeding Modalities on Splanchnic Oxygenation, NCT05513495,  https://clinicaltrials.gov/ct2/results cond=&term=NCT05513495&cntry=TR&state=&city=&dist= . Retrospectively registered, date of registration: August 2022. What is Known: • It is known that preterm infants with IUGR are at increased risk of hypoxic-ischemic intestinal damage and impaired splanchnic oxygenation. What is New: • The key factor in splanchnic oxygenation of preterm infants with IUGR is feeding, not the feeding modality (drip or intermittent). • In addition, the umbilical vein catheter had a negative impact on splanchnic oxygenation.

Abdominal Near Infrared Spectroscopy can be reliably used to measure splanchnic oxygenation changes in preterm infants

OBJECTIVE

Near-infrared spectroscopy (NIRS) allows assessment of regional tissue oxygen delivery and extraction. There are doubts regarding reliability of gut NIRS measurements. This study assesses reliability of NIRS for monitoring gut oxygenation.

STUDY DESIGN

Splanchnic tissue haemoglobin index (sTHI), tissue oxygenation index (sTOI) and fractional tissue oxygen extraction (sFTOE) changes during blood transfusion were measured using NIRS and compared to stable control infants. Infants were grouped into 3 chronological age groups: 1-7, 8-28 and ≥29 days of life.

RESULTS

sTHI, sTOI significantly increased, and sFTOE reduced following blood transfusion in all age group infants (n = 59), with no changes seen in control infants (n = 12). Baseline characteristics including gestational age and feed volumes did not differ between groups.

CONCLUSION

Gut perfusion measured by NIRS improved in infants who received blood transfusion, a change not seen in the control group, thus suggesting NIRS is a reliable method to measure splanchnic tissue oxygenation.

Association between Abnormal Antenatal Doppler Characteristics and Gastrointestinal Outcomes in Preterm Infants

Antenatal Doppler disturbances are associated with fetal hypoxia and may induce a brain-sparing vascular redistribution at the expense of splanchnic circulation, possibly predisposing to gut complications. We aimed to compare several gastrointestinal outcomes among very-low-birthweight (VLBW) preterm infants with different antenatal Doppler features. VLBW infants born between 2010-2022 were retrospectively included and stratified into the following clusters based on antenatal Doppler characteristics: normal Doppler (controls); absent or reversed end-diastolic flow in the umbilical artery (UA-AREDF) alone or also in the ductus venosus (UA+DV-AREDF); and abnormal Doppler with or without brain-sparing redistribution. The following outcomes were evaluated: time to reach full enteral feeds (FEF), feeding intolerance (FI), necrotizing enterocolitis (NEC), and spontaneous intestinal perforation (SIP). Overall, 570 infants were included. Infants born following UA+DV-AREDF had significantly higher FI, NEC, and SIP rates and achieved FEF later compared to controls. Increased FI prevalence and a longer time to FEF compared to controls were also observed among UA-AREDF infants and in the presence of brain-sparing redistribution, which also increased NEC rates. Antenatal Doppler abnormalities exacerbate the gastrointestinal risks of preterm infants. Detailed knowledge of Doppler features can aid in identifying those at highest risk of intestinal complications who may benefit from tailored enteral feeding management.

The relationship of foetal superior mesenteric artery blood flow and the time to first meconium passage in newborns with late-onset foetal growth restriction

This study aimed to assess the relationship between the foetal superior mesenteric artery (SMA) Doppler and the time to first meconium passage (FMP) in foetuses with late-onset foetal growth restriction. This single-centre, prospective, observational, cohort study included 57 patients with late-onset FGR. The newborn infants were divided into two groups: preterm (36.8%) and term (63.2%). The time to FMP of the infants was compared to the foetal SMA parameters obtained within a week before delivery. The median time to FMP was similar between two groups (p = .31). The SMA pulsatility index (PI) was higher in the preterm group (p < .01). There was no correlation between foetal SMA PI or resistance index and time to FMP. In late-onset FGR infants, our study found no association between SMA Doppler measurements and time to FMP. However, a significant difference was detected in SMA PI between preterm and term infants. Impact StatementWhat is already known in this subject? Foetal growth restriction (FGR) can affect splanchnic circulation of the foetus and this alteration can be associated with some disorders including necrotising enterocolitis.What do the results of this study add? Superior mesenteric artery (SMA) Doppler indices are not associated with first meconium passage in neonates with late-onset foetal growth restriction. The pulsatility index of SMA is significantly higher in foetuses delivered before term.What are the implications of these findings for clinical practice and/or further research? Further research should be conducted to investigate the relationship between foetal SMA Doppler indices and neonatal gastrointestinal morbidities in foetuses with early onset FGR with Doppler anomalies. These studies can shed light from the prenatal to the postnatal period, allowing clinicians to predict potential problems and take precautions.

Regional cerebral and splanchnic tissue oxygen saturation in preterm infants - Longitudinal normative measurements

BACKGROUND

To investigate regional splanchnic and cerebral tissue oxygen saturation in preterm infants <30 weeks gestation.

METHODS

Cerebral (cTOI) and splanchnic (sTOI) Tissue Oxygenation Index were measured weekly in 5 min epochs for a total period of 60 min using NIRS (NIRO-300) for the first 8 weeks of life, in 48 appropriately grown preterm infants born at <30 weeks gestation. Infants who developed HPI and/or NEC (n = 12) and those that died (n = 1) were excluded from our main outcome measure of regional gut and cerebral tissue oxygenation in healthy preterm infants <30 weeks gestation.

RESULTS

Median birthweight 789 g (460-1486), gestational age 25⁺⁶ weeks (23⁺⁰-29⁺¹) and 51.4% female. 217 NIRS measurements were completed across the first 8 weeks of life. Mean weekly cTOI ranged from 56.8-65.4% and sTOI ranged from 36.7-46.0%. Mean cTOI was significantly higher than mean sTOI (p < 0.001) throughout the first 8 weeks of life. Mean cTOI decreased significantly with increasing postnatal age [-0.59% each week (-1.26% to -0.07%) p = 0.04]. None of the examined confounding factors had a significant effect.

CONCLUSIONS

This is the first report of regional cerebral and splanchnic tissue oxygen saturation ranges during the first 8 weeks of life for preterm infants born at <30 weeks gestation.

Could Near Infrared Spectroscopy (NIRS) be the new weapon in our fight against Necrotising Enterocolitis?

There is no ideal single gut tissue or inflammatory biomarker available to help to try and identify Necrotising Enterocolitis (NEC) before its clinical onset. Neonatologists are all too familiar with the devastating consequences of NEC, and despite many advances in neonatal care the mortality and morbidity associated with NEC remains significant. In this article we review Near Infrared Spectroscopy (NIRS) as a method of measuring regional gut tissue oxygenation. We discuss its current and potential future applications, including considering its effectiveness as a possible new weapon in the early identification of NEC.

A systematic review of the definitions and prevalence of feeding intolerance in preterm infants

BACKGROUND & AIMS

Feeding intolerance (FI) is a common phenomenon experienced in preterm infants in neonatal intensive care units, as well as being a focus of many research studies into feeding methods, particularly in relation to comorbidities. There is no widely accepted definition of FI. This systematic review aimed to explore the range of definitions used for FI and provide an estimate of the prevalence amongst preterm infants.

METHODS

Searches were completed on MEDLINE (includes the Cochrane library), Embase, PsycInfo, CINAHL, NHS Evidence and Web of Science. Inclusion criteria; preterm infants in neonatal units, a clear definition of FI, >10 patients and be available in English language. Case reports were excluded.

RESULTS

One hundred studies were included. Definitions of FI were inconsistent. Studies were grouped according to definition used into: Group A - measuring gastric residual volume (GRV) only; group B - GRV and abdominal distension (AD); group C - GRV, AD and gastrointestinal symptoms (GI) which included any of vomiting, bilious vomiting and blood in stool; group D- GRV and GI; group E - AD and GI; group F - GI only and group G - any other elements used. Meta-analysis demonstrated that prevalence of FI between groups varied from 15 to 30% with an overall prevalence of 27% (95% confidence interval 23-31%). Group A had the highest prevalence. Review of time to full enteral feed was performed (37 studies) which demonstrated a range of 11.3-18.3 days depending on which FI definition used.

DISCUSSION

Definitions of FI in research are inconsistent, a similar finding to that seen in studies in both paediatric and adult critical care populations. The difficulty of defining FI in the preterm population is the concern regarding necrotising enterocolitis, with some studies using an overlap in their definitions, despite differing pathophysiology and management. Due to the heterogeneity of data obtained in this review regarding definitions used, further robust research is required in order to conclude which elements which should be used to define FI in this population.

PROSPERO NUMBER

CRD42019155596. Registered November 2019.

NIRS as a biomarker of bowel ischaemia & surgical pathology: A meta-analysis of studies in newborns

OBJECTIVE

We performed a meta-analysis on Near-infrared Spectroscopy (NIRS) as a biomarker of bowel ischaemia.

SUMMARY BACKGROUND DATA

NIRS allows non-invasive assessment of gastrointestinal regional oxygen saturation (GrSO₂). Studies to date have focused on the feasibility of NIRS in clinical practice and its reproducibility. GrSO₂ can be used alone, or in conjunction with cerebral NIRS to give a Cerebral Splanchnic Oxygenation Ratio (CSOR). We assess published data on abdominal NIRS as a marker of bowel ischaemia.

METHODS

A literature review was conducted using the PRISMA method. Data on GrSO₂ and CSOR in controls and patients with confirmed ischaemia was included in a meta-analysis, and used to identify a diagnostic threshold.

RESULTS

14 studies were identified. Meta-analysis demonstrated that GrSO₂ (p < 0.01) and CSOR (p < 0.01) were significantly lower in neonates with bowel pathology associated with ischaemia than controls. Area under the curve for GrSO₂ was 0.80, with Youden's index highest (0.52) at a GrSO₂ of 42% (specificity 91% and sensitivity 62%). For CSOR, area under the curve is 0.89, with Youden's index highest (0.69) at 0.76 (specificity of 80%, sensitivity 90%).

CONCLUSIONS

Splanchnic NIRS correlates with bowel ischaemia. Low GrSO₂ is consistently associated with ischaemia, although a specific cut off level in each patient is hard to define. However, values below 42% correlate strongly with ischaemia while values above 52% are more suggestive of patients without bowel pathology. CSOR of below 0.76 is strongly suggestive of ischaemia. Trends within individuals are likely to be able to provide even more clinically correlatable and diagnostic data.

Enteral Nutrition in Term Infants with Congenital Heart Disease: Knowledge Gaps and Future Directions to Improve Clinical Practice

Optimal nutrition is essential to improve short- and long-term outcomes in newborns with congenital heart disease (CHD). Nevertheless, several issues on nutritional management and concerns about the potential risk of complications related to enteral feeding exist. This narrative review aims to summarize and discuss the available literature on enteral feeding in term infants with CHD. A wide variability in feeding management exists worldwide. Emerging approaches to improve nutritional status and outcomes in infants with CHD include: implementation of a standardized enteral feeding protocol, both preoperative and postoperative, clearly defining time of initiation and advancement of enteral feeds, reasons to withhold, and definitions of feeding intolerance; early minimal enteral feeding; enteral feeding in stable term infants on hemodynamic support; evaluation of enteral feeding in term infants with umbilical arterial catheters and during prostaglandin infusion; assessment and support of oro-motor skills; and promotion and support of breastfeeding and provision of mother's own milk or donor milk when mother's own milk is not available. As evidence from term infants is scarce, available observations and recommendations partially rely on studies in preterm infants. Thus, well-designed studies assessing standardized clinically relevant outcomes are needed to provide robust evidence and shared recommendations and practices.

Measurement of gut oxygenation in the neonatal population using near-infrared spectroscopy: a clinical tool?

CONTEXT

Near-infrared spectroscopy (NIRS) is a non-invasive bedside monitor of tissue oxygenation that may be a useful clinical tool in monitoring of gut oxygenation in newborn infants.

OBJECTIVE

To systematically review literature to determine whether NIRS is a reliable tool to monitor gut oxygenation on neonatal units.

DATA SOURCES

PubMed and Embase databases were searched using the terms 'neonate', 'preterm infants', 'NIRS' and 'gut oxygenation' (2001-2018).

STUDY SELECTION

Studies were included if they met inclusion criteria (clinical trial, observational studies, neonatal population, articles in English and reviewing regional gut oxygen saturations) and exclusion criteria (not evaluating abdominal NIRS or regional oxygen saturations).

DATA EXTRACTION

Two authors independently searched PubMed and Embase using the predefined terms, appraised study quality and extracted from 30 studies the study design and outcome data.

LIMITATIONS

Potential for publication bias, majority of studies were prospective cohort studies and small sample sizes.

RESULTS

Thirty studies were reviewed assessing the validity of abdominal NIRS and potential application in neonates. Studies reviewed assessed abdominal NIRS in different settings including normal neonates, bolus and continuous feeding, during feed intolerance, necrotising enterocolitis and transfusion with packed red cells. Several observational studies demonstrated how NIRS could be used in clinical practice.

CONCLUSIONS

NIRS may prove to be a useful bedside tool on the neonatal unit, working alongside current clinical tools in the monitoring of newborn infants (preterm and term) and inform clinical management. We recommend further studies including randomised controlled trials looking at specific measurements and cut-offs for abdominal NIRS for use in further clinical practice.

Reference Values for Abdominal Circumference in Premature Infants

Objectives: Abdominal distention is a common indicator of feeding intolerance in premature newborns. In the absence of a precise definition, abdominal distention and its degree are highly subjective. The aim of this study was to construct references and smoothed percentiles for abdominal circumference (AC) and AC to head circumference (HC) ratio (AC/HC) in infants born between 24 weeks and 34 weeks of gestational age. Methods: ACs and HCs were collected weekly in eutrophic premature infants without congenital abdominal or cerebral malformation. AC and HC charts were modeled using the LMS method, excluding measures associated with abdominal distention at clinical examination or intracranial abnormality at cerebral ultrasounds. Changes in AC and AC/HC over time were studied by repeated-measures analysis using mixed-effects linear models. Results: A total of 1,605 measurements were made in 373 newborns with a mean gestational age of 31 [29-33] weeks and mean birth weight of 1,540 [1,160-1,968] g. Of these measurements, 1,220 were performed in normal conditions. Gestational age, postnatal age, singleton status, and respiratory support were significantly associated with AC and AC/HC. LMS curves were generated according to gestational age groups and postnatal age, with coherent profiles. AC/HC was 0.91 [0.86-0.95] in absence of abdominal distention. It was higher in cases of abdominal distention (0.95 [0.89-1.00], p < 0.001) and necrotizing enterocolitis (0.98 [0.93-1.07], p < 0.001). Conclusions: References constructed for AC and AC/HC might be used to assess feeding tolerance in premature infants. AC/HC was more relevant than AC to rationalize the diagnosis of abdominal distention.

To Feed or Not to Feed: A Critical Overview of Enteral Feeding Management and Gastrointestinal Complications in Preterm Neonates with a Patent Ductus Arteriosus

The management of enteral feeds in preterm infants with a hemodynamically significant patent ductus arteriosus (hs-PDA) is a major challenge for neonatologists due to the fear of gastrointestinal (GI) complications. This review aims to analyze the available evidence on the complex relation between the presence and management of PDA, enteral feeding practices, and GI outcomes in the preterm population. There is limited evidence, based on small and heterogeneous trials, that hs-PDA may affect the splanchnic hemodynamic response to enteral feeds. While the presence of PDA seems a risk factor for adverse GI outcomes, the benefits of feeding withholding during pharmacological PDA treatment are controversial. The lack of robust evidence in support of or against a timely feeding introduction or feeding withholding during pharmacological PDA closure in preterm neonates does not allow to draw any related recommendation. While waiting for further data, the feeding management of this population should be carefully evaluated and possibly individualized on the basis of the infants’ hemodynamic and clinical characteristics. Large, multicentric trials would help to better clarify the physiological mechanisms underlying the development of gut hypoperfusion, and to evaluate the impact of enteral feeds on splanchnic hemodynamics in relation to PDA features and treatment.

The effect of enteral bolus feeding on regional intestinal oxygen saturation in preterm infants is age-dependent: a longitudinal observational study

Background

The factors that determine the effect of enteral feeding on intestinal perfusion after preterm birth remain largely unknown. We aimed to determine the effect of enteral feeding on intestinal oxygen saturation (r_intSO₂) in preterm infants and evaluated whether this effect depended on postnatal age (PNA), postmenstrual age (PMA), and/or feeding volumes. We also evaluated whether changes in postprandial r_intSO₂ affected cerebral oxygen saturation (r_cSO₂).

Methods

In a longitudinal observational pilot study using near-infrared spectroscopy we measured r_intSO₂ and r_cSO₂ continuously for two hours on postnatal Days 2 to 5, 8, 15, 22, 29, and 36. We compared preprandial with postprandial values over time using multi-level analyses. To assess the effect of PNA, PMA, and feeding volumes, we performed Wilcoxon signed-rank tests or logistic regression analyses. To evaluate the effect on r_cSO₂, we also used logistic regression analyses.

Results

We included 29 infants: median (range) gestational age 28.1 weeks (25.1–30.7) and birth weight 1025 g (580–1495). On Day 5, r_intSO₂ values decreased postprandially: mean (SE) 44% (10) versus 35% (7), P = .01. On Day 29, r_intSO₂ values increased: 44% (11) versus 54% (7), P = .01. Infants with a PMA ≥ 32 weeks showed a r_intSO₂ increase after feeding (37% versus 51%, P = .04) whereas infants with a PMA < 32 weeks did not. Feeding volumes were associated with an increased postprandial r_intSO₂ (per 10 mL/kg: OR 1.63, 95% CI, 1.02–2.59). We did not find an effect on r_cSO₂ when r_intSO₂ increased postprandially.

Conclusions

Our study suggests that postprandial r_intSO₂ increases in preterm infants only from the fifth week after birth, particularly at PMA ≥ 32 weeks when greater volumes of enteral feeding are tolerated. We speculate that at young gestational and postmenstrual ages preterm infants are still unable to increase intestinal oxygen saturation after feeding, which might be essential to meet metabolic demands.

Trial registration

For this prospective longitudinal pilot study we derived patients from a larger observational cohort study: CALIFORNIA-Trial, Dutch Trial Registry NTR4153.

Effect of Patent Ductus Arteriosus on Splanchnic Oxygenation at Enteral Feeding Introduction in Very Preterm Infants

Because of its possible effect on mesenteric blood flow, the presence of a hemodynamically significant patent ductus arteriosus (PDA) is often of concern for the introduction of enteral feeds in preterm neonates. Near-infrared spectroscopy allows a continuous monitoring of splanchnic oxygenation (SrSO2) and may provide useful hemodynamic information. This observational study evaluated SrSO2 patterns in response to first feed administration in 50 preterm infants <32 weeks' gestation with different ductal status. According to their echocardiographic characteristics, the enrolled infants were divided into the following groups: pulsatile PDA with hemodynamically significant features, restrictive PDA, and no evidence of PDA. The presence of PDA, either with restrictive or hemodynamically significant characteristics, does not significantly affect SrSO2 response to enteral feeding introduction and is not associated with increased rates of gut complications. This finding may provide encouraging evidence in support of early enteral nutrition in very preterm infants with PDA.

[Splanchnic oximetry in small for gestational age neonates in relation to prenatal doppler study]

INTRODUCTION

Among small for gestational age neonates, foetal Doppler enables the identification of placental insufficency aetiology and the classification of severity in small for gestational age neonates. There are studies that associate the Doppler data with alterations in the intestinal flow of the newborn, but its relationship with intestinal oximetry has been little studied.

OBJECTIVE

To assess whether there is a relationship between prenatal Doppler data and abdominal oximetry in small for gestational age neonates MATERIAL AND METHODS: A prospective observational study carried out on neonates>32 weeks with a birth weight<P10. The severity of placental insufficiency was classified according to prenatal Doppler criteria. Splanchnic oximetry was monitored during the first three days of life and a comparative analysis of the oximetry data was performed according to the prenatal Doppler alteration severity.

RESULTS

A total of 53 patients were evaluated. Significant differences were observed in the mean regional oximetry (rSO₂) between patients with moderate or severe placental failure and those with normal or slightly altered prenatal Doppler: 42±10 vs. 71.3±10 (P<.001). These differences were maintained during the first 3 days of life. Standard patterns of splanchnic oximetry were identified depending on the degree of placental insufficiency.

CONCLUSIONS

There is a correlation between the foetal Doppler and the splanchnic oximetry pattern during the first days of life. Neonates with moderate or severe placental insufficiency have more altered abdominal oximetry patterns, making it a useful technique to evaluate the degree of placental insufficiency and the risk of oral intolerance in small for gestational age neonates.

Feed intolerance in preterm neonates with antenatal reverse end diastolic flow (REDF) in umbilical artery: a retrospective cohort study

Background: Feed intolerance is common in growth-restricted infants with antenatal AREDF (absent or reverse end-diastolic flow) and presumed to be more severe in those with reverse end diastolic flow (REDF). Natural history of feeding in REDF is rarely reported in the literature.Aims and objectives: To determine the incidence of feed intolerance and necrotizing enterocolitis (NEC) in neonates with antenatal REDF.Design: Preterm inborn neonates with gestation <37 weeks with antenatal REDF diagnosed between January 2015 and September 2017 were included in this retrospective cohort study. The primary outcome was the proportion of neonates having feed intolerance and NEC till discharge or death or transfer to other hospitals and time to achieve full enteral feeding (150 ml/kg/day).Results: Out of total 67 born with antenatal REDF, 8 were transferred out within 48 hours, 8 records not available and 4 excluded due to major malformations. The mean (SD) gestation and birth weight of the remaining 48 neonates were 32 (2) weeks and 1096 (291) g. The median (IQR) age of initiation of feeds was 30 (24-37) hours. Feeds were advanced by median (range) 20 (10-20) ml/kg/day in which 22 babies (45%) had at least 1 episode of feed intolerance at a median (IQR) age of 79 (40-120) hours requiring nil per oral for next 48 (18-96) hours. Full feeds were reached by median age (IQR) of nine (8-12) days. Only 3 neonates (6%) had NEC stage 2 or above as per Bell's staging.Conclusions: Feed intolerance is common in neonates with REDF though the risk of NEC is not high.What is known on this subject?Neonates with antenatal AREDF are at increased risk of feed intolerance and necrotizing enterocolitis.Early introduction of enteral feeds in neonates with AREDF with appropriate monitoring is safe without increased risk of necrotizing enterocolitis.AEDF which progresses to REDF is associated with increased morbidity.What does this study add?Early enteral feeding as early as 24 hours can be initiated in REDF if there are no abdominal symptoms and signs.Feed intolerance is high in REDF cases.The risk of NEC is not higher than what is seen in AEDF cases.

Splanchnic NIRS monitoring in neonatal care: rationale, current applications and future perspectives

Near infrared spectroscopy (NIRS) provides a non-invasive, continuous monitoring of regional tissue oxygenation. NIRS assessment of neonatal splanchnic oxygenation (SrSO₂) has gained increasing interest over the last decade, as local hypoxia and ischemia underlie the most feared gut complications in neonates. Current literature provides encouraging evidence in support of SrSO₂ reliability in detecting mesenteric hemodynamic changes related to various physiological and pathological conditions in-term and preterm infants. Even so, while splanchnic NIRS monitoring looks promising for investigating gut physiopathology in research settings, further studies are needed to evaluate its feasibility as a routine monitoring tool in neonatal care and to investigate its potential role in clinical decision making. After a brief introduction to NIRS technical principles, this review aims to provide a complete overview of current neonatal applications for splanchnic NIRS monitoring, to discuss its possible limitations and to suggest future directions for research and clinical applications.