Bolus Gastric Feeds Improve Nutritional Delivery to Mechanically Ventilated Pediatric Medical Patients: Results of the COntinuous vs BOlus (COBO2) Multi-Center Trial

The enteroendocrine axis and its effect on gastrointestinal function, nutrition, and inflammation

PURPOSE OF REVIEW

Gastrointestinal (GI) dysfunction limits enteral nutrition (EN) delivery in critical illness and contributes to systemic inflammation. The enteroendocrine (EE) axis plays an integral role in this interface between nutrition, inflammation, and GI function in critical illness. In this review, we present an overview of the EE system with a focus on its role in GI inflammation and function.

RECENT FINDINGS

Enteroendocrine cells have been primarily described in their role in macronutrient digestion and absorption. Recent research has expanded on the diverse functions of EE cells including their ability to sense microbial peptides and metabolites and regulate immune function and inflammation. Therefore, EE cells may be both affected by and contribute to many pathophysiologic states and interventions of critical illness such as dysbiosis, inflammation, and alternative EN strategies. In this review, we present an overview of EE cells including their growing role in nonnutrient functions and integrate this understanding into relevant aspects of critical illness with a focus on EN.

SUMMARY

The EE system is key in maintaining GI homeostasis in critical illness, and how it is impacted and contributes to outcomes in the setting of dysbiosis, inflammation and different feeding strategies in critical illness should be considered.

Timing of enteral nutrition and parenteral nutrition in the PICU

The timing of nutrition support initiation has the potential to positively impact nutrition and clinical outcomes in infants and children with critical illness. Early enteral nutrition within 24-48 h and attainment of both a 60% energy and protein goal by the end of the first week of pediatric intensive care unit admission are reported to be significantly associated with improved survival in large observational studies. The results of one randomized controlled trial demonstrated increased morbidity in infants and children with critical illness assigned to early vs delayed supplemental parenteral nutrition. Observational studies in this population also suggest increased mortality with exclusive parenteral nutrition and worse nutrition outcomes when parenteral nutrition is delayed. Subsequently, current nutrition support guidelines recommend early enteral nutrition and avoidance of early parenteral nutrition, although the available evidence used to create the guidelines was inadequate to inform bedside nutrition support practice to improve outcomes. These guidelines are limited by the included studies with small numbers and heterogeneity of patients and research design that confound study outcomes and interpretation. This article provides a narrative review of the timing of nutrition support on outcomes in infants and children with critical illness, strategies to optimize timing and adequacy of nutrition support, and literature gaps, including the timing of parenteral nutrition initiation for children with malnutrition and those with contraindications to enteral nutrition and accurate measurement of energy requirements.

Intermittent feeding with an overnight fast versus 24-h feeding in critically ill neonates, infants, and children: An open-label, single-centre, randomised controlled trial

BACKGROUND & AIMS

Critically ill children are fed day and night, assuming this improves enteral tolerance and the probability of achieving nutritional goals. It was previously shown that a fasting response, reflected by increased ketosis, at least partly explained the beneficial outcome of delayed initiation of supplemental parenteral nutrition. This study aims to investigate whether an overnight fast increases ketosis and is feasible and safe in critically ill children.

METHODS

The Continuousversus Intermittent Nutrition in Paediatric Intensive Care (ContInNuPIC) study is a randomised controlled trial in a tertiary referral Paediatric Intensive Care Unit (PICU) in the Netherlands. Critically ill children (term newborn-18 years) with an expected PICU stay ≥48 h, dependent on artificial nutrition, were eligible. Participants were randomly assigned (1:1, stratified for age group) to intermittent feeding, with interruption of feedings during an age-dependent overnight period of eight to 12 h, or to continuous feeding, with the administration of feedings day and night. In both groups, similar daily caloric targets were pursued. For children younger than one year, mandatory minor glucose infusions were provided during fasting. The primary outcome was the feasibility, defined as two conditions (1): a significant difference in the patients' highest daily ketone (3-β-hydroxybutyrate, BHB) levels during each overnight period, and (2): non-inferiority regarding daily caloric intake, examined using a two-part mixed-effects model with a predefined non-inferiority margin of 33%, in an intention-to-treat analysis. The study is registered in the Netherlands Trial Register (NL7877).

RESULTS

Between May 19, 2020, and July 13, 2022, 140 critically ill children, median (first quartile; third quartile) age 0.3 (0.1; 2.7) years, were randomised to intermittent (n = 67) or continuous feeding (n = 73). In the intermittent feeding group, BHB levels were significantly higher (median 0.4 (0.2; 1.0) vs. 0.3 (0.1; 0.7) mmol/L, p < 0.001). The ratio of total caloric intake in the intermittent feeding group to the intake in the continuous feeding group was not consistently significantly more than 0.67, thus not proving non-inferiority. No severe, resistant hypoglycaemic events, nor severe gastrointestinal complications related to the intervention occurred, and feeding intolerance did not occur more often in the intermittent than in the continuous feeding group.

CONCLUSION

Compared with day and night feeding, intermittent feeding with an overnight fast and mandatory glucose infusion for children younger than one year marginally increased ketosis and did not lead to more hypoglycaemic incidents in critically ill children. Because non-inferiority regarding daily caloric intake was not proven, the feasibility of an overnight fast could not be shown in the current study. However, as feeding intolerance did not increase during the condensed feeding periods, the nutritional intake was probably limited by the prescription of nutrition and interruptions. More research is needed to determine the optimal level and duration of clinically relevant ketosis and the best method to achieve this.

Continuous versus Intermittent Enteral Feeding in Critically Ill Children: A Systematic Review

Administration of enteral nutrition (EN) in critically ill pediatric patients admitted to the pediatric intensive care unit (PICU) constitutes a major challenge due to the increased risk of complications, as well as the lack of well-trained healthcare professionals. EN is usually delivered via cyclic, continuous, or intermittent feeding; however, a number of potential barriers have been reported in the literature regarding different feeding regimens. The purpose of this review was to assess the effectiveness of continuous and intermittent bolus feeding on critically ill children. A systematic search was conducted in PubMed, Scopus Cochrane Central Register of Controlled Trials (CENTRAL) and a clinical trial registry up to September 2022, including randomized controlled trials (RCTs) published in the English language. Four studies met the inclusion criteria with a total population of 288 patients admitted to the PICU. Three studies were rated with a high risk of bias and one with some concerns. There was high heterogeneity between the studies in regard to the reporting of outcomes. Three studies measured the total time needed to reach prescribed caloric intake with conflicting results, while two studies evaluated the length of stay (LOS) in PICU with no difference between the two arms. One study assessed the time weaning from mechanical ventilation, favoring the bolus group. No data were provided for gastric residual volume (GRV), anthropometric measurements, and biochemical markers. Additional randomized trials with better methodology are needed to assess the efficacy of the two enteral feeding regimens in critically ill PICU patients.

Intermittent versus continuous enteral nutrition in critically ill children: A pre-planned secondary analysis of an international prospective cohort study

BACKGROUND & AIMS

Intermittent enteral nutrition (EN) may have physiologic benefits over continuous feeding in critical illness. We aimed to compare nutrition and infection outcomes in critically ill children receiving intermittent or continuous EN.

METHODS

International, multi-center prospective observational study of mechanically ventilated children, 1 month to 18 years of age, receiving EN. Percent energy or protein adequacy (energy or protein delivered/prescribed × 100) and acquired infection rates were compared between intermittent and continuous EN groups using adjusted-multivariable and 4:1 propensity-score matched (PSM) analyses. Sensitivity analyses were performed after excluding patients who crossed over between intermittent and continuous EN.

RESULTS

1375 eligible patients from 66 PICUs were included. Patients receiving continuous EN (N = 1093) had a higher prevalence of respiratory illness and obesity, and lower prevalence of neurologic illness and underweight status on admission, compared to those on intermittent EN (N = 282). Percent energy or protein adequacy, proportion of patients who achieved 60% of energy or protein adequacy in the first 7 days of admission, and rates of acquired infection were not different between the 2 groups in adjusted-multivariable and propensity score matching analyses (P > 0.05).

CONCLUSION

Intermittent versus continuous EN strategy is not associated with differences in energy or protein adequacy, or acquired infections, in mechanically ventilated, critically ill children. Until further evidence is available, an individualized feeding strategy rather than a universal approach may be appropriate.