Evaluation of splanchnic oximetry, Doppler flow velocimetry in the superior mesenteric artery and feeding tolerance in very low birth weight IUGR and non-IUGR infants receiving bolus versus continuous enteral nutrition

Splanchnic-cerebral oxygenation ratio associated with packed red blood cell transfusion in preterm infants

BACKGROUND

Splanchnic-cerebral oxygenation ratio (SCOR), the ratio of splanchnic tissue oxygen (StO₂ s) to simultaneously measured cerebral tissue oxygen (StO₂ c), has been described as a surrogate to detect impaired splanchnic oxygenation associated with hypoperfusion status such as necrotizing enterocolitis. This concept is based on the presumption that any change in SCOR indicates a corresponding change in splanchnic tissue oxygenation as the numerator, whereas cerebral tissue oxygenation as the denominator remains stable. However, it is questionable to utilise this concept to detect splanchnic oxygenation changes in the context of packed red blood cell transfusion (PRBCT).

AIM

The current study examines the contribution of both cerebral and splanchnic oxygenation components to PRBCT-associated SCOR changes in preterm infants.

DESIGN

Prospective cohort study.

SETTING

Neonatal intensive care.

PATIENTS

Hemodynamically stable infants: Gestation <32 weeks; birth weight <1500 g; postmenstrual age <37 weeks: tolerating ≥120 ml/kg/day feed volume.

INTERVENTIONS

PRBCT at 15 ml/kg, over 4 h.

MAIN OUTCOME MEASURES

Transfusion-associated changes were determined by performing mixed models for repeated measures analysis between the 4-h mean pre-transfusion values (SCOR 0, StO₂ s 0, and StO₂ c 0) and the post-transfusion hourly mean values for the next 28 h (SCOR 1-28, StO₂ s 1-28, and StO₂ c 1-28). Dunnett's method was used to adjust for the multiplicity of the p value.

RESULTS

Of 30 enrolled infants 14 [46.7%] male; median [IQR] birth weight, 923 [655-1064] g; gestation, 26.4 [25.5-28.1] weeks; enrolment weight, 1549 [1113-1882] g; and postmenstrual age, 33.6 [32.4-35.0] weeks, one infant was excluded because of corrupted NIRS data. With the commencement of PRBCT, SCOR demonstrated a downward trend throughout the study period. This drift was associated with an increasing StO₂ c trend, while StO₂ s remained unchanged throughout the study period.

CONCLUSIONS AND RELEVANCE

PRBCT-associated SCOR decrease suggests improvement in cerebral oxygenation rather than worsening splanchnic oxygenation. Our study underlines that it is necessary to determine individual components of SCOR, namely cerebral and splanchnic StO₂ to understand SCOR changes in the context of PRBCT.

Optimal Nutrition Parameters for Neonates and Infants with Congenital Heart Disease

Congenital heart defects are known causes of malnutrition. Optimal nutritional management is paramount in improving short and long-term prognosis for neonates and infants with congenital heart malformations, as current strategies target preoperative and postoperative feeding requirements. Standardized enteral and/or parenteral feeding protocols, depending on the systemic implications of the cardiac defect, include the following common practices: diagnosing and managing feeding intolerance, choosing the right formula, and implementing a monitoring protocol. The latest guidelines from the American Society for Parenteral and Enteral Nutrition and the European Society of Paediatric and Neonatal Intensive Care, as well as a significant number of recent scientific studies, offer precious indications for establishing the best feeding parameters for neonates and infants with heart defects.

A new physiologic-based integrated algorithm in the management of neonatal hemodynamic instability

Physiologic-based management of hemodynamic instability is proven to guide the logical selection of cardiovascular support and shorten the time to clinical recovery compared to an empiric approach that ignores the heterogeneity of the hemodynamic instability related mechanisms. In this report, we classified neonatal hemodynamic instability, circulatory shock, and degree of compensation into five physiologic categories, based on different phenotypes of blood pressure (BP), other clinical parameters, echocardiography markers, and oxygen indices. This approach is focused on hemodynamic instability in infants with normal cardiac anatomy.Conclusion: The management of hemodynamic instability is challenging due to the complexity of the pathophysiology; integrating different monitoring techniques is essential to understand the underlying pathophysiologic mechanisms and formulate a physiologic-based medical recommendation and approach. What is Known: • Physiologic-based assessment of hemodynamics leads to targeted and pathophysiologic-based medical recommendations. What is New: • Hemodynamic instability in neonates can be categorized according to the underlying mechanism into five main categories, based on blood pressure phenotypes, systemic vascular resistance, and myocardial performance. • The new classification helps with the targeted management and logical selection of cardiovascular support.

Continuous nasogastric milk feeding versus intermittent bolus milk feeding for preterm infants less than 1500 grams

BACKGROUND

Milk feedings can be given via nasogastric tube either intermittently, typically over 10 to 20 minutes every two or three hours, or continuously, using an infusion pump. Although the theoretical benefits and risks of each method have been proposed, their effects on clinically important outcomes remain uncertain.  OBJECTIVES: To examine the evidence regarding the effectiveness of continuous versus intermittent bolus tube feeding of milk in preterm infants less than 1500 grams.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to run comprehensive searches in the Cochrane Central Register of Controlled Trials (CENTRAL 2020, Issue 7) in the Cochrane Library; Ovid MEDLINE and Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Daily and Versions; and CINAHL (Cumulative Index to Nursing and Allied Health Literature) on 17 July 2020. We also searched clinical trials databases and the reference lists of retrieved articles for randomised controlled trials (RCTs) and quasi-RCTs.

SELECTION CRITERIA

We included RCTs and quasi-RCTs comparing continuous versus intermittent bolus nasogastric milk feeding in preterm infants less than 1500 grams.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed all trials for relevance and risk of bias. We used the standard methods of Cochrane Neonatal to extract data. We used the GRADE approach to assess the certainty of evidence. Primary outcomes were: age at full enteral feedings; feeding intolerance; days to regain birth weight; rate of gain in weight, length and head circumference; and risk of necrotising enterocolitis (NEC).

MAIN RESULTS

We included nine randomised trials (919 infants) in this updated Cochrane Review. One study is awaiting classification. Seven of the nine included trials reported data from infants with a maximum weight of between 1000 grams and 1400 grams. Two of the nine trials included infants weighing up to 1500 grams. Type(s) of milk feeds varied, including human milk (either mother's own milk or pasteurised donor human milk), preterm formula, or mixed feeding regimens. In some instances, preterm formula was initially diluted. Earlier studies also used water to initiate feedings. We judged six trials as unclear or high risk of bias for random sequence generation. We judged four trials as unclear for allocation concealment. We judged all trials as high risk of bias for blinding of care givers, and seven as unclear or high risk of bias for blinding of outcome assessors. We downgraded the certainty of evidence for imprecision, due to low numbers of participants in the trials, and/or wide 95% confidence intervals, and/or for risk of bias. Continuous compared to intermittent bolus (nasogastric and orogastric tube) milk feeding Babies receiving continuous feeding may reach full enteral feeding almost one day later than babies receiving intermittent feeding (mean difference (MD) 0.84 days, 95% confidence interval (CI) -0.13 to 1.81; 7 studies, 628 infants; low-certainty evidence).  It is uncertain if there is any difference between continuous feeding and intermittent feeding in terms of number of days of feeding interruptions (MD -3.00 days, 95% CI -9.50 to 3.50; 1 study, 171 infants; very low-certainty evidence). It is uncertain if continuous feeding has any effect on days to regain birth weight (MD -0.38 days, 95% CI -1.16 to 0.41; 6 studies, 610 infants; low-certainty evidence). The certainty of evidence is low and the 95% confidence interval is consistent with possible benefit and possible harm. It is uncertain if continuous feeding has any effect on rate of gain in weight compared with intermittent feeding (standardised mean difference (SMD) 0.09, 95% CI -0.27 to 0.46; 5 studies, 433 infants; very low-certainty evidence). Continuous feeding may result in little to no difference in rate of gain in length compared with intermittent feeding (MD 0.02 cm/week, 95% CI -0.04 to 0.08; 5 studies, 433 infants; low-certainty evidence). Continuous feeding may result in little to no difference in rate of gain in head circumference compared with intermittent feeding (MD 0.01 cm/week, 95% CI -0.03 to 0.05; 5 studies, 433 infants; low-certainty evidence). It is uncertain if continuous feeding has any effect on the risk of NEC compared with intermittent feeding (RR 1.19, 95% CI 0.67 to 2.11; 4 studies, 372 infants; low-certainty evidence). The certainty of evidence is low and the 95% confidence interval is consistent with possible benefit and possible harm.

AUTHORS' CONCLUSIONS

Although babies receiving continuous feeding may reach full enteral feeding slightly later than babies receiving intermittent feeding, the evidence is of low certainty. However, the clinical risks and benefits of continuous and intermittent nasogastric tube milk feeding cannot be reliably discerned from current available randomised trials. Further research is needed to determine if either feeding method is more appropriate for the initiation of feeds. A rigorous methodology should be adopted, defining feeding protocols and feeding intolerance consistently for all infants. Infants should be stratified according to birth weight and gestation, and possibly according to illness.

Intestinal Oxygenation and Survival After Surgery for Necrotizing Enterocolitis: An Observational Cohort Study

OBJECTIVE

To assess whether regional intestinal oxygen saturation (rintSO2) and regional cerebral oxygen saturation (rcSO2) measurements aid in estimating survival of preterm infants after surgery for NEC.

SUMMARY OF BACKGROUND DATA

Predicting survival after surgery for NEC is difficult yet of the utmost importance for counseling parents.

METHODS

We retrospectively studied prospectively collected data of preterm infants with surgical NEC who had available rintSO2 and rcSO2 values measured via near-infrared spectroscopy 0-24 hours preoperatively. We calculated mean rintSO2 and rcSO2 for 60-120 minutes for each infant. We analyzed whether preoperative rintSO2 and rcSO2 differed between survivors and non-survivors, determined cut-off points, and assessed the added value to clinical variables.

RESULTS

We included 22 infants, median gestational age 26.9 weeks [interquartile range (IQR): 26.3-28.4], median birth weight 1088 g [IQR: 730-1178]. Eleven infants died postoperatively. Preoperative rintSO2, but not rcSO2, was higher in survivors than in non-survivors [median: 63% (IQR: 42-68) vs 29% (IQR: 21-43), P < 0.01), with odds ratio for survival 4.1 (95% confidence interval, 1.2-13.9, P = 0.02) per 10% higher rintSO2. All infants with rintSO2 values of >53% survived, whereas all infants with rintSO2 <35% died. Median C-reactive protein [138 mg/L (IQR: 83-179) vs 73 mg/L (IQR: 12-98), P < 0.01), lactate [1.1 mmol/L (IQR: 1.0-1.6) vs 4.6 mmol/L (IQR: 2.8-8.0), P < 0.01], and fraction of inspired oxygen [25% (IQR: 21-31) vs 42% (IQR: 30-80), P < 0.01] differed between survivors and non-survivors. Only rintSO2 remained significant in the multiple regression model.

CONCLUSIONS

Measuring rintSO2, but not rcSO2, seems of added value to clinical variables in estimating survival of preterm infants after surgery for NEC. This may help clinicians in deciding whether surgery is feasible and to better counsel parents about their infants' chances of survival.

Predicting intestinal recovery after necrotizing enterocolitis in preterm infants

BACKGROUND

Intestinal recovery after NEC is difficult to predict in individuals. We evaluated whether several biomarkers predict intestinal recovery after NEC in preterm infants.

METHODS

We measured intestinal tissue oxygen saturation (r_intSO₂) and collected urinary intestinal-fatty acid binding protein (I-FABP_u) levels 0-24 h and 24-48 h after NEC onset, and before and after the first re-feed. We assessed intestinal recovery in two ways: time to full enteral feeding (FEFt; below or equal/above group's median) and development of post-NEC complications (recurrent NEC/post-NEC stricture). We determined whether the r_intSO₂, its range, and I-FABP_u differed between groups.

RESULTS

We included 27 preterm infants who survived NEC (Bell's stage ≥ 2). Median FEFt was 14 [IQR: 12-23] days. Biomarkers only predicted intestinal recovery after the first re-feed. Mean r_intSO₂ ≥ 53% combined with mean r_intSO_2range ≥ 50% predicted FEFt < 14 days with OR 16.7 (CI: 2.3-122.2). The r_intSO_2range was smaller (33% vs. 51%, p < 0.01) and I-FABP_u was higher (92.4 vs. 25.5 ng/mL, p = 0.03) in case of post-NEC stricture, but not different in case of recurrent NEC, compared with infants without complications.

CONCLUSION

The r_intSO₂, its range, and I-FABP_u after the first re-feed after NEC predicted intestinal recovery. These biomarkers have potential value in individualizing feeding regimens after NEC.

Association of Bolus Feeding With Splanchnic and Cerebral Oxygen Utilization Efficiency Among Premature Infants With Anemia and After Blood Transfusion

IMPORTANCE

The pathogenesis of transfusion-associated necrotizing enterocolitis remains elusive. Splanchnic hypoperfusion associated with packed red blood cell transfusion (PRBCT) and feeding has been implicated, but studies of splanchnic tissue oxygenation with respect to feeding plus PRBCT are lacking.

OBJECTIVE

To investigate the oxygen utilization efficiency of preterm gut and brain challenged with bolus feeding during anemia and after transfusion using near-infrared spectroscopy.

DESIGN, SETTING, AND PARTICIPANTS

This prospective cohort study conducted from September 1, 2014, to November 30, 2016, at a tertiary neonatal intensive care unit included 25 hemodynamically stable infants with gestational age less than 32 weeks, birth weight less than 1500 g, and postmenstrual age younger than 37 weeks. Data analysis was performed from August 1, 2017, to October 31, 2018.

EXPOSURES

Infants received PRBCT (15 mL/kg for 4 hours) and at least 120 mL/kg daily of second hourly bolus feedings.

MAIN OUTCOMES AND MEASURES

Splanchnic fractional tissue oxygen extraction (FTOEs) and cerebral fractional tissue oxygen extraction (FTOEc) measures were made during 75-minute feeding cycles that comprised a 15-minute preprandial feeding phase (FP0) and 4 contiguous 15-minute postprandial feeding phases (FP1, FP2, FP3, and FP4; each 15 minutes long). The intraindividual comparisons of feeding-related changes were evaluated during the pretransfusion epoch (TE0: 4 hours before onset of transfusion) and 3 TEs after transfusion (TE1: first 8 hours after PRBCT completion; TE2: 9-16 hours after PRBCT completion; and TE3: 17-24 hours after PRBCT completion).

RESULTS

Of 25 enrolled infants (13 [52%] female; median birth weight, 949 g [interquartile range {IQR}, 780-1100 g]; median gestational age, 26.9 weeks [IQR, 25.9-28.6 weeks]; median enrollment weight, 1670 g [IQR, 1357-1937 g]; and median postmenstrual age, 34 weeks [IQR, 32.9-35 weeks]), 1 infant was excluded because of corrupted near-infrared spectroscopy data. No overall association was found between FTOEs and FPs in a multivariable repeated-measures model that accounted for transfusion epochs (primary analysis approach) (FP0: mean estimate, 11.64; 95% CI, 9.55-13.73; FP1: mean estimate, 12.02; 95% CI, 9.92-14.11; FP2: mean estimate, 12.77; 95% CI, 10.68-14.87; FP3: mean estimate, 12.54; 95% CI, 10.45-14.64; FP4: mean estimate, 12.98; 95% CI, 10.89-15.08; P = .16 for the FP association). However exploratory analyses of postprandial changes in FTOEs undertaken for each transfusion epoch separately found evidence of increased postprandial FTOEs during TE1 (mean [SD] FTOEs, 10.55 [5.5] at FP0 vs 13.21 [5.96] at FP4, P = .046). The primary and exploratory analyses found no association between FTOEc and feeding phases, suggesting that cerebral oxygenation may be protected.

CONCLUSIONS AND RELEVANCE

The findings suggest that enteral feeding may be associated with gut ischemia and potentially transfusion-associated necrotizing enterocolitis. The postprandial changes in FTOEs appear to warrant further investigation in larger randomized studies.

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.

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.

[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.

Investigating the Role of Near-Infrared Spectroscopy in Neonatal Medicine

Near-infrared spectroscopy (NIRS) is a clinical tool that provides a bedside method of noninvasively measuring continuous, "real-time" oxygen consumption and monitoring for potential ischemia of somatic tissues, particularly the brain, kidneys, and intestine in neonates. Although the concept of NIRS seems promising, its implementation into clinical practice has been inconsistent for various reasons, including difficulty in interpreting regional oxygen saturation (rSO2), the wide variation in types of NIRS monitors and probes, the cost of new equipment, different monitoring modalities, large discrepancies in both intra- and interindividual use, a lack of defined universal normative values, and little to no data on outcomes or potentially harmful interventions made based on rSO2 readings. We combine findings from previously published informational articles and studies on the use of NIRS in neonatal medicine to provide a comprehensive overview of this tool and identify potential indications for clinical use.

Feeding issues in IUGR preterm infants

Intra-uterine growth restriction (IUGR) is a severe and quite common problem in obstetrics. A condition of placental dysfunction can lead to a cardiovascular adaptation in the fetus characterized by a redistribution of cardiac output to maintain oxygen supply to the heart, adrenal glands and brain - the so-called brain sparing effect - at the expense of visceral organs (such as the gastrointestinal system). This condition may predispose IUGR infants to impaired gut function after birth. A higher incidence of necrotizing enterocolitis (NEC) is documented in IUGR preterm infants. Therefore, a common practice in neonatal intensive care units is to delay feeds to reduce the risk of feeding intolerance. Recent trials, however, have shown that early enteral feeding in IUGR infants is safe and it would appear, on the basis of the few available data, that breast milk could offer protection against NEC. This mini-review offers an update on feeding in IUGR infants. Future perspectives on the usefulness of Doppler and regional splanchnic and cerebral saturation monitoring for deciding when to start feeding are also provided.

Feeding tolerance of preterm infants appropriate for gestational age (AGA) as compared to those small for gestational age (SGA)

Preterm infants are often considered too unstable to be fed enterally so they are exposed to complications related to a prolonged enteral fasting. Our study aims to compare feeding tolerance of adequate for gestational age (AGA) versus small for gestational age (SGA) infants and to evaluate which perinatal factors affect feeding tolerance (measured as time to achieve full enteral feeding, FEF). Inborn infants with a gestational age (GA) less than 32 weeks, born from January 2006 to December 2010, were eligible for this study. We enrolled 310 infants. The time to FEF was longer for SGA infants than for AGA, while a longer GA was associated to a reduced time to FEF. A beneficial effect was observed for antenatal steroids, while Apgar score below 7, the administration of inotrops or caffeine, the occurrence of sepsis or NEC and the presence of PDA were associated to a longer time to FEF. When evaluated jointly with a multivariate analysis, GA (p < 0.0001), antenatal steroids prophylaxis (p = 0.002), SGA (p < 0.0001) and occurrence of NEC (p = 0.0002) proved to have independent prognostic impact on the time to FEF. Feeding tolerance is better as GA increases, and worsen in SGA infants. Antenatal betamethasone is effective in reducing the time to FEF in both AGA and SGA.