Do PICU patients meet technical criteria for performing indirect calorimetry?

Critical Care Nutrition for Children - Where are we now?

In this review, we outline key practical components of the nutritional management of critically-ill children in the context of the current peer reviewed literature and identify vital knowledge gaps for further investigation. Emerging areas of research are discussed, including skeletal muscle ultrasonography for measurement of skeletal muscle, and the potential future role of pre- and probiotics.

Measuring Energy Requirements of Traumatic Brain Injury Patients in Pediatric Intensive Care With Indirect Calorimetry: A Comparison With Empiric Methods

OBJECTIVES

Energy requirements following moderate or severe pediatric traumatic brain injury (TBI) have not been fully elucidated. Indirect calorimetry (IC) is the gold standard for measuring resting energy expenditure (MREE) in PICU. However, technical complexity limits its use. We aimed to determine whether MREE differs from standard of care energy estimation and delivery in a cohort of pediatric patients following moderate to severe TBI during PICU admission.

DESIGN

Retrospective case series study.

SETTING

Single-center, 16-bed general PICU in Canada between May 2011 and January 2019.

PATIENTS

Children (0-18 yr) admitted to a PICU for moderate (Glasgow Coma Scale [GCS] 9-12) to severe TBI (GCS < 9) and had an IC study performed while mechanically ventilated.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

During the study period, 245 patients were admitted with the diagnosis of trauma with TBI. The study includes a convenience sample of 26 patients with severe ( n = 23) and moderate ( n = 3) TBI who underwent a total of 34 IC measurements. MREE varied considerably from 29% to 144% of predicted energy expenditure. Using Bland-Altman comparative analysis, neither Schofield nor World Health Organization predictive equations were in agreement with MREE. Only one measurement revealed that the patient was appropriately fed (energy provided in nutrition support was within 10% of MREE); 10 (38%) measurements revealed overfeeding and 15 (58%) underfeeding at the time of testing.

CONCLUSIONS

The present study adds to the small body of literature highlighting the limitations of predictive equations to evaluate energy requirements following moderate to severe pediatric TBI. IC, when feasible, should be used as the preferred method to orient PICU teams to feed such vulnerable patients.

Effect of three enteral diets with different protein contents on protein metabolism in critically ill infants: a randomized controlled trial

INTRODUCTION

The optimal intake to improve protein metabolism without producing adverse effects in seriously ill infants has yet to be established. The aim of our study was to analyse whether an increased protein intake delivered through enteral nutrition would be associated with an improvement in nitrogen balance and serum protein levels in critically ill infants.

METHODS

We conducted a multicentre, prospective randomized controlled trial (December 2016-June 2019). The sample consisted of critically ill infants receiving enteral nutrition assigned randomly to 3 protein content groups: standard diet (1.7 g/dL), protein-enriched diet (2.7 g/dL) and high protein-enriched diet (5.1 g/dL). Blood and urine tests were performed, and we assessed nitrogen balance at baseline and at 3-5 days of the diet. We analysed variations in nitrogen balance and serum protein levels (total protein, albumin, transferrin, prealbumin, and retinol-binding protein) throughout the study period.

RESULTS

Ninety-nine infants (33 per group) completed the study. We did not find any differences were between groups in demographic characteristics, severity scores or prescribed medications, except for corticosteroids, administered in a higher proportion of patients in the third group. We observed significant increases in prealbumin and retinol-binding protein levels in patients receiving the protein-enriched and high protein-enriched diets at 3-5 days compared to baseline. The nitrogen balance increased in all groups, but the differences were not significant in the high protein-enriched group. There were no differences in gastrointestinal tolerance. Patients fed high protein-enriched formula had higher levels of serum urea, with a higher incidence of hyperuraemia in this group.

CONCLUSION

Enteral administration of higher amounts of protein improves serum protein levels in critically ill children. A protein intake of 2.2 g/kg/day is generally safe and well tolerated, whereas an intake of 3.4 g/kg/day may produce hyperuraemia in some patients.

A methodological and clinical approach to measured energy expenditure in the critically ill pediatric patient

The metabolic response to injury and stress is characterized initially by a decreased energy expenditure (Ebb phase) followed by an increased metabolic expenditure (Flow phase). Indirect calorimetry is a methodology utilized to measure energy expenditure and substrate utilization by measuring gas exchange in exhaled air and urinary nitrogen. The use of indirect calorimetry in critically ill patients requires precise equipment to obtain accurate measurements. The most recent guidelines suggested that measured energy expenditure by indirect calorimetry be used to determine energy requirements. This article reviews the methodological and clinical use of indirect calorimetry in critically ill pediatric patients.

Case Report: Novel Monitoring for Anaerobic Conditions Detected by Respiratory Quotient in a Critically Ill Pediatric Patient

BACKGROUND

Hyperlactemia after cardiopulmonary bypass is associated with adverse events during the early postoperative period in children. Serum lactate levels, a standard marker of anaerobic metabolism, are determined by the production, conversion and clearance of lactate, and may lag behind the anaerobic response. Here, we report a neonatal case under anaerobic conditions after cardiac surgery, whose expired gas parameters dramatically changed before a rise in blood lactate.

CASE PRESENTATION

A 23-day-old girl with tetralogy of Fallot was admitted to the pediatric intensive care unit after modified Blalock-Taussig shunt operation. As hemoconcentration increased and pleural fluid and ascites accumulated, we performed partial exchange transfusion to prevent shunt occlusion. Ten minutes after partial exchange transfusion, oxygen uptake and carbon dioxide production measured by indirect calorimetry suddenly dropped, while the respiratory quotient began to rise steeply before hyperlactatemia developed a few hours later.

CONCLUSION

Analysis of expired gas in critically ill children can detect the transition from aerobic to anaerobic conditions before hyperlactatemia.

Energy Expenditure in Mechanically Ventilated Korean Children: Single-Center Evaluation of a New Estimation Equation

OBJECTIVES

Accurate assessments of energy expenditure are vital for determining optimal nutritional support, especially in critically ill children. We evaluated current methods for energy expenditure prediction, in comparison with indirect calorimetry, and developed a new estimation equation for mechanically ventilated, critically ill Korean children.

DESIGN

Single-center retrospective study.

SETTING

Fourteen-bed pediatric medical ICU in a tertiary care children's hospital.

PATIENTS

Pediatric patients admitted to the PICU between October 2017 and September 2019 with a measured energy expenditure by indirect calorimetry.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total 95 pediatric patients (70 in derivation cohort for development of a new predictive equation and 25 in validation cohort) were included. Mean measured energy expenditure of group A was 66.20 ± 15.35 kcal/kg/d. All previously established predictive equations underestimated the predicted energy expenditure, compared with the measured energy expenditure, except the Food and Agriculture/World Health Organization/United Nations University equation. The Schofield-Height and Weight equation showed the best performance among the tested predictive equations for the entire cohort (least bias, -68.58 kcal/d; best percentage, 108.46% ± 33.60%) compared with the measured energy expenditure. It was also the best performing predictive equation in subgroup analysis by age, sex, nutritional status, and organ failure. Because some discrepancies remained between the measured energy expenditure and predicted energy expenditures, we developed a new estimation equation using multiple regression analysis and those variables significantly associated with our current measured energy expenditures: Energy expenditure = -321.264 + 72.152 × (body weight, kg)-1.396 × (body weight) + 5.668 × height (cm) + organ dysfunction* (*hematologic, 76.699; neurologic, -87.984). This new estimation equation showed the least bias and best percentage compared with previous predictive equations (least bias, 15.51 kcal/d; best percentage, 102.30% ± 28.10%).

CONCLUSIONS

There are significant disparities between measured and calculated energy expenditures. We developed a new estimation equation based on measured energy expenditure data that shows better performance in mechanically ventilated Korean children than other equations. This new estimation equation requires further prospective validation in pediatric series with a range in body habitus.

Role of age of critically ill children at time of exposure to early or late parenteral nutrition in determining the impact hereof on long-term neurocognitive development: A secondary analysis of the PEPaNIC-RCT

Background & aims

Early use of parenteral nutrition (early-PN), as compared with withholding it for one week (late-PN), in the PICU, has shown to slow down recovery from critical illness and impair long-term development of 6 neurocognitive/behavioural/emotional functions assessed 2 years later. Given that key steps in brain maturation occur at different times during childhood, we hypothesised that age at time of exposure determines long-term developmental impact of early-PN.

Methods

The 786 children who were neurocognitively tested 2 years after participation in the PEPaNIC-RCT were included in this study. First, for each studied long-term outcome, interaction between randomisation to early-PN versus late-PN and age was assessed with multivariable linear regression analysis. Subsequently, for outcomes with an interaction p ≤ 0.15, the impact of early-PN versus late-PN was analysed, after adjustment for risk factors, for 4 subgroups defined based on developmentally-relevant age at time of exposure [≤28 days (n = 121), 29 days to 11 months (n = 239), 11 months to <5 years (n = 223) and ≥5 years (n = 203)].

Results

Interaction between randomisation and age was present for weight, and parent-reported inhibitory control, cognitive flexibility, working memory, planning/organisation, metacognition, total executive functioning, and internalising and total behavioural/emotional problems. Subgroup analyses revealed that none of the age-groups revealed benefit, whereas children aged 29 days to <11 months were most vulnerable to harm by early-PN for development of inhibitory control (p = 0.008), working memory (p = 0.009), planning/organisation (p = 0.004), metacognition (p = 0.008), and total executive functioning (p = 0.004), and for internalising (p = 0.005) and total behavioural/emotional problems (p = 0.01). Children aged 11 months to <5 years revealed harm by early-PN for development of inhibitory control (p = 0.003). In contrast, children aged ≥5 years and neonates aged ≤28 days appeared less vulnerable.

Conclusions

Critically ill children aged 29 days to 11 months at time of exposure were identified as most vulnerable to developmental harm evoked by early-PN.

Clinical trials.gov

NCT01536275.

A systematic review and quantitative analysis of resting energy expenditure prediction equations in healthy overweight and obese children and adolescents

BACKGROUND

Resting energy expenditure (REE) estimates are often needed in young people and can be predicted using prediction equations based on body weight. However, these equations may perform poorly in those who are obese and overweight. The aim of this systematic review was to identify equations based on simple anthropometric and demographic variables that provide the most accurate and precise estimates of REE in healthy obese and overweight young people.

METHODS

Systematic searches for relevant studies in healthy obese and overweight young people aged ≤18 years were undertaken using PubMed, Scopus, Cinahl, OpenGrey and Cochrane Library (completed January 2018). Search terms included metabolism, calorimetry, obesity and prediction equation. Data extraction, study appraisal and synthesis followed PRISMA guidelines.

RESULTS

From 390 screened titles, 13 studies met inclusion criteria. The most accurate REE predictions (least biased) were provided by Schofield equations [+0.8% (3-18 years); 0% (11-18 years); +1.1% (3-10 years)]. The most precise REE estimations (percentage of predictions ± 10% of measured) for 11-18 years were provided by Mifflin equations (62%) and, for 7-18 years, by the equations of Schmelzle (57%), Henry (56%) and Harris Benedict (54%). Precision of Schofield predictions was 43% in both age groups. No accuracy data were available for those <3 years or for precision for those <7 years.

CONCLUSIONS

No single equation provided accurate and precise REE estimations in this population. Schofield equations provided the most accurate REE predictions so are useful for groups. Mifflin equations provided the most precise estimates for individuals aged 11-18 years but tended to underestimate REE.

Review of Outcomes Used in Nutrition Trials in Pediatric Critical Care

BACKGROUND

Generating robust evidence within pediatric intensive care (PIC) can be challenging because of low patient numbers and patient heterogeneity. Systematic reviews may overcome small study biases but are limited by lack of standardization in outcome measures and their definition. Trials of nutrition interventions in PIC are increasing; thus, we wanted to examine the outcome measures being used in these trials.

OBJECTIVE

Our objective was to systematically describe outcome measures used when a nutrition intervention has been evaluated in a PIC randomized controlled trial.

METHODS

A systematic literature review of all studies involving a PIC trial of a nutrition intervention was undertaken from January 1, 1996, until February 20, 2018.

RESULTS

Twenty-nine trials met the criteria and were reviewed. They included a total of 3226 patients across all trials. Thirty-seven primary outcomes and 83 secondary outcomes were found. These were categorized into PIC-related outcomes (infection, intensive care dependency, organ dysfunction, and mortality) and nutrition outcomes (energy targets, nutrition parameters, and feeding tolerance). We found large variation in the outcome measures used. Outcome domains of energy targets, feeding tolerance, and infection were not adequately defined.

CONCLUSIONS

Considerable variation in the outcome measures chosen and their definitions exist within PIC nutrition trials. Optimal nutrition outcomes for PIC must be agreed upon and defined, specifically domains of nutrition efficiency, nutrition tolerance, and non-nutrition PIC outcomes. The next step is to conduct an international Delphi study to gain expert consensus and develop a core outcome set to be reported in future pediatric nutrition trials.

Early Supplemental Parenteral Nutrition in Critically Ill Children: An Update

In critically ill children admitted to pediatric intensive care units (PICUs), enteral nutrition (EN) is often delayed due to gastrointestinal dysfunction or interrupted. Since a macronutrient deficit in these patients has been associated with adverse outcomes in observational studies, supplemental parenteral nutrition (PN) in PICUs has long been widely advised to meeting nutritional requirements. However, uncertainty of timing of initiation, optimal dose and composition of PN has led to a wide variation in previous guidelines and current clinical practices. The PEPaNIC (Early versus Late Parenteral Nutrition in the Pediatric ICU) randomized controlled trial recently showed that withholding PN in the first week in PICUs reduced incidence of new infections and accelerated recovery as compared with providing supplemental PN early (within 24 hours after PICU admission), irrespective of diagnosis, severity of illness, risk of malnutrition or age. The early withholding of amino acids in particular, which are powerful suppressors of intracellular quality control by autophagy, statistically explained this outcome benefit. Importantly, two years after PICU admission, not providing supplemental PN early in PICUs did not negatively affect mortality, growth or health status, and significantly improved neurocognitive development. These findings have an important impact on the recently issued guidelines for PN administration to critically ill children. In this review, we summarize the most recent literature that provides evidence on the implications for clinical practice with regard to the use of early supplemental PN in critically ill children.

NUTRI-REAPED study: nutritional assessment of French critically ill children and nutrition practice survey in French-speaking pediatric intensive care units

BACKGROUND

Impaired nutritional status is adversely associated with suboptimal outcomes in critically ill children. Undernutrition at pediatric intensive care unit (PICU) admission ranges from 15 to 65%. A lack of knowledge of the nutritional status of children in French PICUs prevents us from specifically targeting education. This study aims to describe the nutritional status of children in French PICUs and to assess nutritional practices and physicians' knowledge of nutrition, in order to focus NutriSIP (the French-speaking PICU nutrition group) future education programs. A prospective observational multicenter point prevalence study was conducted in French PICUs, recruiting all children admitted over three different weeks. Anthropometric measurements were taken (weight, height/length, mid-upper arm, and head circumferences), in order to calculate nutritional indices. Nutritional status was defined according to WHO Body Mass Index z-score and dynamic assessment based on growth faltering detection. Concurrently, PICU physicians and PICU nurses from seven French-speaking countries completed a survey to ascertain knowledge about local nutritional care practices and overall nutrition knowledge. PICU physicians' responses were compared to PICU nurses' responses (previously published).

RESULTS

Four hundred and thirty-two children were included in the observational study from 27 French PICUs. Undernutrition was diagnosed in 18.5% of them, young age and underlying chronic condition being the two independent risk factors. Faltering growth was diagnosed in 4.8% and overweight in 7.4%. Subjective nutritional assessment was not accurate. Thirty-eight French-speaking PICUs completed the survey. These showed nutritional practices frequently did not comply with international guidelines, especially regarding nutritional goals, and the reasons for withholding enteral nutrition. Comparison between physicians' and nurses' responses to the survey showed large discrepancies.

CONCLUSION

Undernutrition is frequent at admission in French PICUs. Nutritional status should be assessed using a holistic approach, because of the potential impact on outcome. French-speaking PICU healthcare professionals need further nutrition education, in order to improve nutritional practices to comply with international recommendations. This study will serve as a baseline to focus NutriSIP teaching programs in the future.

Modification of Nutrition Therapy During Continuous Renal Replacement Therapy in Critically Ill Pediatric Patients: A Narrative Review and Recommendations

Introduction

Nutrition is an important part of treatment in critically ill children. Clinical guidelines for nutrition adaptations during continuous renal replacement therapy (CRRT) are lacking. We collected and evaluated current knowledge on this topic and provide recommendations.

Methods

Questions were produced to guide the literature search in the PubMed database.

Results

Evidence is scarce and extrapolation from adult data was often required. CRRT has a direct and substantial impact on metabolism. Indirect calorimetry is the preferred method to assess resting energy expenditure (REE). Moderate underestimation of REE is common but not clinically relevant. Formula‐based calculation of REE is inaccurate and not validated in critically ill children on CRRT. The nutrition impact of nonintentional calories delivered as citrate, lactate, and glucose during CRRT must be considered. Quantifying nitrogen balance is not feasible during CRRT. Protein delivery should be increased by 25% to compensate for losses in the effluent. Fats are not removed by CRRT and should not be adapted during CRRT. Electrolyte disturbances are frequently present and should be treated accordingly. Vitamins B1, B6, B9, and C are lost in the effluent and should be adapted to the effluent dose. Trace elements, with the exception of selenium, are not cleared in relevant quantities. Manganese accumulation is of concern because of potential neurotoxicity.

Conclusion

Current recommendations regarding nutrition support in pediatric CRRT must be extrapolated from adult studies. Recommendations are provided, based on the weak level of evidence. Additional research on this topic is warranted.

[Research advances in nutritional support for critically ill children]

Most critically ill children are in a state of serious stress and tend to develop malnutrition, which may reduce the body's ability to fight against diseases and repair damaged tissues and thus aggravate their conditions. Reasonable and effective nutritional support for critically ill children can improve their nutritional status and prognosis, and so it is necessary to offer nutritional support for critically ill children. This article reviews the research on nutritional support for critically ill children and the current status of clinical application. It also introduces the main methods for nutritional support, including enteral nutrition and parenteral nutrition, and elaborates on the new methods for nutritional support, such as early enteral nutrition, enteral immunonutrition, and supplementary parenteral nutrition, in order to provide a reference for nutritional support for critically ill children.

Can energy intake alter clinical and hospital outcomes in PICU?

BACKGROUND & AIMS

Energy is essential for the treatment and recovery of children admitted to Pediatric Intensive Care Units (PICU). There are significant immediate and long-term health consequences of both under- and over-feeding in this population. Energy requirements of critically ill children vary depending on age, nutritional status, sepsis, fever, pharmacotherapy, and duration and stage of critical illness. This study aimed to determine the incidence of over- and under-feeding and to compare hospital outcomes between these feeding categories. Secondary outcomes were collected to describe the association between feeding categories and biochemistries (serum lactate, triglycerides, C-reactive protein).

METHODS

An ethics approved retrospective study of children admitted to PICU was performed. All intubated patients admitted to PICU (2008-2013) were included, except those in which an IC test was not feasible. Data collection included demographics, the primary outcome variable reported as under feeding (<90%MREE), appropriate (MREE ±10%) or overfeeding (>110% MREE) determined through comparison of measured resting energy expenditure (MREE) using indirect calorimetry (IC) to actual energy intake based on predicted basal metabolic rate (PBMR) and clinical outcomes mechanical ventilation and PICU length of stay (LOS). Data were analysed with descriptive methods, ANOVA and linear regression models.

RESULTS

A total of 139 patients aged 10 (range 0.03-204) months were included. Sixty (43%) were female and 77 (55%) were admitted after a surgical procedure. A total of 210 IC tests were conducted showing a statistically significant difference between MREE measurements and PBMR (p = 0.019). Of the 210 measurements, only 26 measures (12.4%) demonstrated appropriate feeding, while 72 (34.3) were underfed and 112 (53.3%) were overfed. Children who were overfed had significantly longer PICU LOS (median 45.5, IQR 47.8 days) compared to those children in the appropriately fed (median 21.0, IQR 54.5 days), and underfed groups (median 16.5, IQR 21.3 days). There was a mean difference between the over and under feeding category and ventilation days after adjusting for age and PRISM score (p = 0.026), suggesting decreased mechanical ventilation days for underfed. Children who were underfed had significantly higher CRP (median 75.5, IQR 152.8 mg/L) compared to those children in the appropriately fed (median 57.8, IQR 90.9 mg/L) and overfed groups (median 22.4, IQR 56.2 mg/L).

CONCLUSIONS

This retrospective study confirms that estimations of energy expenditure in critically ill children are inaccurate leading to unintended under and overfeeding. Importantly under feeding seems to be associated with fewer mechanical ventilation days and PICU LOS. Further research is required to elucidate the role of optimal nutrition in altering clinical variables in this population.