Guidelines for the provision of nutrition support therapy in the adult critically ill patient: The American Society for Parenteral and Enteral Nutrition.

BACKGROUND: This guideline updates recommendations from the 2016 American Society for Parenteral and Enteral Nutrition (ASPEN)/Society of Critical Care Medicine (SCCM) critical care nutrition guideline for five foundational questions central to critical care nutrition support. METHODS: The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) process was used to develop and summarize evidence for clinical practice recommendations. Clinical outcomes were assessed for (1) higher vs lower energy dose, (2) higher vs lower protein dose, (3) exclusive isocaloric parenteral nutrition (PN) vs enteral nutrition (EN), (4) supplemental PN (SPN) plus EN vs EN alone, (5A) mixed-oil lipid injectable emulsions (ILEs) vs soybean oil, and (5B) fish oil (FO)-containing ILE vs non-FO ILE. To assess safety, weight-based energy intake and protein were plotted against hospital mortality. RESULTS: Between January 1, 2001, and July 15, 2020, 2320 citations were identified and data were abstracted from 36 trials including 20,578 participants. Patients receiving FO had decreased pneumonia rates of uncertain clinical significance. Otherwise, there were no differences for any outcome in any question. Owing to a lack of certainty regarding harm, the energy prescription recommendation was decreased to 12-25 kcal/kg/day. CONCLUSION: No differences in clinical outcomes were identified among numerous nutrition interventions, including higher energy or protein intake, isocaloric PN or EN, SPN, or different ILEs. As more consistent critical care nutrition support data become available, more precise recommendations will be possible. In the meantime, clinical judgment and close monitoring are needed. This paper was approved by the ASPEN Board of Directors.

Relationship between blood glucose variability and muscle composition in ICU patients receiving nutrition support: A pilot study.

BACKGROUND AND AIMS: Many critically ill patients experience increased blood glucose variability (BGV). The objective of the current pilot study was to assess the relationship between muscle composition (defined as average Hounsfield units (HU)) among ICU patients with an abdominal CT scan within seven days of intubation, and BGV (defined as coefficient of variation (CV)) calculated from blood glucose levels measured each morning while intubated. METHODS: The first serum blood glucose measurement obtained each day during intubation was recorded, blood glucose CV ((mean/SD)∗100) was calculated. Cross-sectional muscle area (CSA; cm2) at the third lumbar region was identified using the -29 to +150 HU range; muscle composition was calculated as the average HU. BGV predictors were determined using linear regression. RESULTS: Eighty-two patients were included (53% female), with a median age of 64 (25th, 75 percentile (IQR): 51, 70) years. The median CV was 29% (IQR: 20, 37); 40% of subjects required insulin. The median CSA was 100.4 cm2 (IQR: 84.0, 120.8) and muscle composition was 20.4 HU (IQR: 12.2, 29.4). Patients received only 36% of estimated calorie requirements. Insulin administration, history of diabetes, and muscle composition were significant BGV predictors. CONCLUSION: Among these adult intubated ICU patients, higher muscle composition was associated with lower BGV. Future research is needed to corroborate these findings, determine other factors associated with poor muscle quality, and identify methods to describe muscle composition for all ICU patients.

The Influence of Timing in Critical Care Nutrition.

Proper timing of critical care nutrition has long been a matter of controversy. Critical illness waxes and wanes in stages, creating a dynamic flux in energy needs that we have only begun to examine. Furthermore, response to nutrition support likely differs greatly at the level of the individual patient in regard to genetic status, disease stage, comorbidities, and more. We review the observational and randomized literature concerning timing in nutrition support, discuss mechanisms of harm in feeding critically ill patients, and highlight the role of precision nutrition for moving the literature beyond the realm of blunt population averages into one that accounts for the patient-specific complexities of critical illness and host genetics.

Impact of MnSOD and GPx1 Genotype at Different Levels of Enteral Nutrition Exposure on Oxidative Stress and Mortality: A Post hoc Analysis From the FeDOx Trial.

BACKGROUND: Converting nutrition support to energy results in mitochondrial free radical production, possibly increasing oxidative stress. Highly prevalent single nucleotide variants (SNV) exist for the genes encoding antioxidant enzymes responsible for the detoxification of reactive oxygen species. Our objective was to explore the interaction between nutrition support and genetic SNV's for two anti-oxidant proteins (rs4880 SNV for manganese superoxide dismutase and rs1050450 SNV for glutathione peroxidase 1) on oxidative stress and secondarily on intensive care unit (ICU) mortality. METHODS: We performed a post-hoc analysis on 34 mechanically ventilated sepsis patients from a randomized control feeding trial. Participants were dichotomized into those who carried both the rs4880 and the rs1050450 at-risk alleles (Risk Group) versus all others (Nonrisk Group). We explored the interaction between genotype and percent time spent in the upper median of energy exposure on oxidative stress and ICU mortality. RESULTS: Adjusting for confounders, the slope of log F2-isoprostane levels across percentage of days spent in the upper median of daily kilocalories per kilogram (kcal/kg) was 0.01 higher in the Risk Group compared to the Non-Risk Group (p=0.01). Every 1 percent increase in days spent in the upper median of daily kcal/kg was associated with an adjusted 10.3 percent increased odds of ICU mortality amongst participants in the Risk Group (odds ratio [OR]=1.103, p=0.06) but was highly insignificant in the Nonrisk group (OR=0.991, P=0.79). CONCLUSION: Nutrition support may lead to increased oxidative stress and worse clinical outcomes in a large percent of ICU patients with an at-risk genotype.

Relationship Between Grocery Shopping Frequency and Home- and Individual-Level Diet Quality Among Low-Income Racial or Ethnic Minority Households With Preschool-Aged Children.

BACKGROUND: The home food environment can shape the diets of young children. However, little is known about modifiable factors that influence home food availability and dietary intake. OBJECTIVE: The purpose of this study was to examine the relationship between grocery shopping frequency with home- and individual-level diet quality. DESIGN: This was a secondary, cross-sectional analyses of data from the Study on Children's Home Food Availability Using TechNology. Data were collected in the homes of participants from November 2014 through March 2016. PARTICIPANTS/SETTINGS: A purposive sample of 97 low-income African American and Hispanic or Latinx parent-child dyads residing in Chicago, IL, enrolled in the study. MAIN OUTCOME MEASURES: The main outcomes were home- and individual-level diet quality. Healthy Eating Index-2010 (HEI-2010) scores were calculated from home food inventory data collected in participants' homes to assess home-level diet quality. To assess individual-level diet quality, HEI-2010 scores were based on multiple 24-hour diet recalls from parent-child dyads. STATISTICAL ANALYSES: Grocery shopping frequency was examined in relation to diet quality at the home and individual levels. Grocery shopping frequency was defined as the number of times households shopped on a monthly basis (ie, once a month, twice a month, 3 times a month, or 4 times or more a month). Multivariable linear regression analysis, controlling for covariates, tested the relationships between grocery shopping frequency and HEI-2010 total and component scores at the home and individual levels. RESULTS: Grocery shopping frequency was positively associated with home-level HEI-2010 scores for total diet, whole grains, and empty calories (higher scores reflect better diet quality) and with individual-level HEI-2010 scores for total and whole fruit (parents only), vegetables (children only), and sodium (children only). CONCLUSIONS: Grocery shopping frequency was associated with multiple dimensions of diet quality at the home and individual levels. These results offer a potential strategy to intervene on home food availability and individual dietary intake.

Effects of taurocholic acid metabolism by gut bacteria: A controlled feeding trial in adult African American subjects at elevated risk for colorectal cancer.

Colorectal cancer (CRC) is the third leading cause of cancer and second leading cause of cancer death in the United States. Recent evidence has linked a high fat and animal protein diet and microbial metabolism of host bile acids as environmental risk factors for CRC development. We hypothesize that the primary bile salt taurocholic acid (TCA) is a key, diet-controlled metabolite whose use by bacteria yields a carcinogen and tumor-promoter, respectively. The work is motivated by our published data indicating hydrogen sulfide (H2S) and secondary bile acid production by colonic bacteria, serve as environmental insults contributing to CRC risk. The central aim of this study is to test whether a diet high in animal protein and saturated fat increases abundance of bacteria that generate H2S and pro-inflammatory secondary bile acids in African Americans (AAs) at high risk for CRC. Our prospective, randomized, crossover feeding trial will examine two microbial mechanisms by which an animal-based diet may support the growth of TCA metabolizing bacteria. Each subject will receive two diets in a crossover design- an animal-based diet, rich in taurine and saturated fat, and a plant-based diet, low in taurine and saturated fat. A mediation model will be used to determine the extent to which diet (independent variable) and mucosal markers of CRC risk and DNA damage (dependent variables) are explained by colonic bacteria and their functions (mediator variables). This research will generate novel information targeted to develop effective dietary interventions that may reduce the unequal CRC burden in AAs.

Real-Time Energy Exposure Is Associated With Increased Oxidative Stress Among Feeding-Tolerant Critically Ill Patients: Results From the FEDOX Trial.

BACKGROUND: Prospective randomized controlled trials (PRCTs) that found harm in patients receiving higher levels of energy exposure have been largely ignored, in part because of the lack of a known mechanism of harm. OBJECTIVE: The current 7-day pilot study is a PRCT and post hoc analysis designed to explore the relationship between energy exposure and oxidative stress (as plasma total F2-isoprostanes) in mechanically ventilated intensive care unit patients with systemic inflammatory response syndrome. METHODS: Thirty-five participants were randomized to receive either 100% or 40% of their estimated energy needs. Our intent-to-treat model found no differences in F2-isoprostanes between groups. A post hoc analysis revealed that on days when participants were in the highest tertile of daily kcal/kg, the real-time energy flow rate within 2 hours of the blood draw was predictive of increased oxidative stress. On these days, participants in the second or third vs the first tertile of real-time energy flow rate experienced a 41.8% (P = .006) or 26.5% (P = .001) increase in F2-isoprostane levels, respectively. This was confirmed through a within-group subanalysis restricted to participants with measurements on both sides of the median of real-time energy flow rate that found a 28.2% F2-isoprostane increase on days in the upper vs lower median of flow rate (P = .002). CONCLUSION: The benefits of feeding may be more nuanced than previously suspected. Our findings imply a potential mechanism of harm in meeting the current recommendations for nutrition support in the critically ill that warrants further investigation.

American Society for Parenteral and Enteral Nutrition Clinical Guidelines: The Validity of Body Composition Assessment in Clinical Populations.

On behalf of the American Society for Parenteral and Enteral Nutrition (ASPEN), a systematic review was conducted to evaluate the best available evidence regarding the validity of relevant body composition methods (eg, dual energy X-ray absorptiometry [DXA], ultrasound [US], and bioelectrical impedance analysis [BIA]) in clinical populations. The guidelines targeted adults >18 years of age with a potentially inflammatory condition or pathological end point associated with a specific disease or clinical condition. In total, 7375 studies were retrieved, and 15 DXA, 7 US, and 23 BIA studies provided applicable data. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses was used to assess the diagnostic accuracy of the test method against a "gold standard" reference. The Grading of Recommendations, Assessment, Development and Evaluation criteria were used to separate the evaluation of the body of evidence from the recommendations. Based on a limited number of studies and expert opinion, DXA is recommended for the assessment of fat mass in patients with a variety of disease states; however, the validity of DXA for lean mass assessment in any clinical population remains unknown. No recommendations can be made at this time to support the use of US or BIA in the clinical setting, as data to support its validity in any specific patient population are limited in scope or by the proprietary nature of manufacture-specific BIA regression models to procure body composition data, respectively. Directions for future research are provided. These clinical guidelines were approved by the ASPEN Board of Directors.

Higher Caloric Exposure in Critically Ill Patients Transiently Accelerates Thyroid Hormone Activation.

INTRODUCTION: The inflammatory response of critical illness is accompanied by nonthyroidal illness syndrome (NTIS). Feeding has been shown to attenuate this process, but this has not been explored prospectively over time in critically ill patients. OBJECTIVE: To explore the impact of calorie exposure on NTIS over time in critically ill patients. METHODS: Mechanically ventilated patients with systemic inflammatory response syndrome (SIRS) were randomized to receive either 100% or 40% of their estimated caloric needs (ECN). Thyroid hormones were measured daily for 7 days or until intensive care unit discharge or death. Mixed level regression modeling was used to explore the effect of randomization group on plasma triiodothyronine (T3), reverse triiodothyronine (rT3), thyroxine (T4), and thyroid stimulating hormone (TSH), as well as the T3/rT3 ratio. RESULTS: Thirty-five participants (n=19 in 100% ECN; n=16 in 40% ECN) were recruited. Adjusting for group differences in baseline T3/rT3 ratio, the parameters defining the fitted curves (intercept, linear effect of study day, and quadratic effect of study day) differed by randomization group (P = 0.001, P = 0.01, and P = 0.02 respectively). Plots of the fitted curves revealed that participants in the 100% ECN group had a 54% higher T3/rT3 ratio on postintervention day 1 compared with the 40% ECN group, a difference which attenuated over time. This was driven by a 23% higher plasma T3 and 10% lower plasma rT3 levels on postintervention 1. CONCLUSIONS: Higher caloric exposure in NTIS patients transiently attenuates the drop of the plasma T3/rT3 ratio, an effect that is minimized and finally lost over the following 3 days of continued higher caloric exposure.

Comparative Effectiveness Trial of an Obesity Prevention Intervention in EFNEP and SNAP-ED: Primary Outcomes.

There is a need to disseminate evidence-based childhood obesity prevention interventions on a broader scale to reduce obesity-related disparities among underserved children. The purpose of this study was to test the comparative effectiveness of an evidence-based obesity prevention intervention, Hip-Hop to Health (HH), delivered through Expanded Food and Nutrition Education Program (EFNEP) and the Supplemental Nutrition Assistance Program-Education (SNAP-Ed) versus the standard curriculum delivered by the programs (Standard Nutrition Education (NE)). A nonequivalent control group design was delivered to compare the effectiveness of HH to NE on weight gain prevention and health behavior outcomes at EFNEP and SNAP-Ed sites. One hundred and fifty-three caregiver-child dyads (n = 103 in the HH group; n = 50 in the NE group) participated in the study. HH is an evidence-based dietary and physical activity intervention for low-income preschool children. The NE curriculum provided lessons for children that are consistent with the Dietary Guidelines for Americans 2010. Data were collected on demographics, anthropometrics, and behavioral variables for parent-child dyads at baseline and postintervention. Mixed model methods with random effects for site and participant were utilized. No differences in child or caregiver diet, physical activity, or screen time by group were found. No between-group differences in child BMI z-score were found; however, caregivers in the HH group lost significantly more weight than those in the NE group. Results from this trial can inform future dissemination efforts of evidenced-based programs for underserved families.

American Society for Parenteral and Enteral Nutrition Guidelines for the Selection and Care of Central Venous Access Devices for Adult Home Parenteral Nutrition Administration.

This document represents the American Society for Parenteral and Enteral Nutrition (ASPEN) clinical guidelines to describe best practices in the selection and care of central venous access devices (CVADs) for the infusion of home parenteral nutrition (HPN) admixtures in adult patients. The guidelines targeted adults >18 years of age in which the intervention or exposure had to include HPN that was administered via a CVAD. Case studies, non-English studies, or studies of CVAD no longer available in the United States were excluded. In total, 564 abstract citations, 350 from Medline and 214 from PubMed/non-MEDLINE databases, were scanned for relevance. Of the 564 citations, 13 studies addressed at least 1 of the 6 guideline-related questions, and none of the studies were prospective and randomized. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) criteria were used to adjust the evidence grade based on assessment of the quality of study design and execution. Recommendations for the CVAD type, composition, or number of lumens to minimize infectious or mechanical complications are based on a limited number of studies and expert opinion of the authors, all very experienced in home infusion therapy. No studies were found that compared best solutions for routine flushing of lumens (eg, heparin versus saline) or for maintaining catheters in situ while treating CVAD mechanical or infectious complications. It is clear that studies to answer these questions are very limited, and further research is needed. These clinical guidelines were approved by the ASPEN Board of Directors.

Author Response to "Unraveling Methodology to Ensure the Search for Optimal Nutrition Quantity in Acute Respiratory Distress Syndrome Remains INTACT".

We thank Drs. Patel, Martindale, and Heyland1 for their interest in our most recent study2 exploring the role of early exposure to recommended energy delivery in critically ill patients with acute respiratory distress syndrome. Their stated concerns center around 3 major areas: (1) the comparability of the population in our study2 with those of INTACT (Intensive Nutrition in Acute Lung Injury: A Clinical Trial); (2) their confusion on the analysis of the relationship between the likelihood of death with energy exposure (table 1 in our article2 ); and (3) their apparent misunderstanding of type I error, type II error, P-values, and power analysis. Our responses to each of these areas are detailed as follows.

Combination of High-Calorie Delivery and Organ Failure Increases Mortality Among Patients With Acute Respiratory Distress Syndrome.

OBJECTIVES: Among critically ill patients, the benefits of nutrition support may vary depending on severity of organ dysfunction. The objective of the current article was to explore the relationship between organ failure and calories exposure with hospital mortality during the first week of acute respiratory distress syndrome. DESIGN: Retrospective observational study. SETTING: Single-center ICU. PATIENTS: Adults admitted to the ICU with a diagnosis of acute respiratory distress syndrome. INTERVENTIONS: Calorie delivery from enteral nutrition, parenteral nutrition, propofol, and dextrose containing fluids were collected for 7 days following intubation. Sequential Organ Failure Assessment score was calculated at ICU admit and for the same 7 days to describe organ dysfunction; four different Sequential Organ Failure Assessment variables were created 1) Sequential Organ Failure Assessment at ICU admit, 2) average Sequential Organ Failure Assessment for the first 7 days following intubation, 3) the highest Sequential Organ Failure Assessment for the first 7 days following intubation, and 4) change in Sequential Organ Failure Assessment from intubation to 7 days later. MEASUREMENTS AND MAIN RESULTS: A total of 298 patients were included. Sequential Organ Failure Assessment at ICU admit, average Sequential Organ Failure Assessment for the first 7 days following intubation, highest Sequential Organ Failure Assessment for the first 7 days following intubation, change in Sequential Organ Failure Assessment from intubation to 7 days later, and calorie delivery the first 7 days following intubation were all associated with increased likelihood of mortality. Compared with patients with low organ failure and low-calorie delivery, those with high-calorie delivery and low organ failure, low-calorie delivery and high organ failure, and the combination of both high organ failure with high-calorie delivery were associated with an incremental increase in the likelihood or mortality. CONCLUSIONS: Organ failure appears to modify the relationship between calorie exposure and ICU outcome. Additional research is needed to identify appropriate thresholds for safe calorie exposure with increased organ failure.

Feeding During Phases of Altered Mitochondrial Activity: A Theory.

Decisions surrounding the timing and dosing of nutrition support are made for thousands of ICU patients daily and yet remain a topic of controversy. Nutrition support designed to replenish resting energy expenditure (REE) early in critical illness has led to worse clinical outcomes in at least three recent prospective randomized clinical trials. Producing sufficient energy from nutrient substrates requires use of the mitochondrial electron transport chain (ETC). This process is functionally linked to the creation of a tightly regulated series of chemical messengers known as reactive oxygen species (ROS). In health, ROS are kept at low levels by a system of mitochondrial/cellular enzymes and antioxidants, allowing ROS to act as a signal for the redox health of the cell. In inflammatory conditions, however, this system is altered, leading to changes in the physiologic function of the ETC such that its usage produces greater ROS per unit of substrate. This increased ROS is capable of deactivating antioxidant systems, as well as activating further ROS-producing pathways and stimulating localized inflammatory activity. We propose that exacerbation of this process at this time by the forced influx of exogenously acquired nutrient substrates leads to mitochondrial damage, amplified ROS production, increased inflammation, decreased ATP-productive capacity, and, eventually, the death of the cell by either apoptosis or necrosis. Knowledge of this process is vital to determining the safe dosing and timing of nutrition support in the ICU. It is possible that the physiologic cost of meeting the REE under these conditions of mitochondrial stress may simply be too high. This paper details the proposed process by which inappropriately timed feeding in critically ill patients may damage the very mitochondria required for its utilization.

The relationship between home- and individual-level diet quality among African American and Hispanic/Latino households with young children.

BACKGROUND: The quality of most Americans' diets is far from optimal. Given that many Americans consume a significant portion of calories in the home, intervening in this setting could be beneficial. However, the relationship between the home food environment and diet quality is not well understood. This study examined the relationship between diet quality at the individual level with home-level diet quality using an index that measures compliance with federal dietary guidance. METHODS: This was a cross sectional study that enrolled 97 African American and Hispanic/Latino low-income parent-child dyads. Diet quality at the individual level was assessed through two 24-h dietary recalls collected for parents and children, respectively. Diet quality at the home level was assessed with two home food inventories conducted in participants' homes. Diet quality scores at the home and individual levels were computed by applying the Healthy Eating Index-2010 (HEI-2010) to these data. Linear models adjusted for potential confounding factors were used to examine the relationship between diet quality at the home and individual levels. RESULTS: Total HEI-2010 scores from parents and children's diets were positively associated with HEI-2010 scores based on home food inventories (parent diet: ß: 0.36, 95% CI: 012-0.60; child diet: 0.38 95% CI: 013-0.62). Positive associations were also observed between individual level and home level subcomponent HEI-2010 scores for total fruit (parent: 0.55 95% CI: 0.16-0.94; child: 0.49 95% CI: 0.03-0.94), whole fruit (parent only: 0.41 95% CI: 0.07-0.74), greens and beans (parent only: 0.39 95% CI: 0.05-0.74), and whole grain (children only: 0.33 95% CI: 0.04-0.63). CONCLUSION: This study demonstrated that individual level diet quality was positively associated with home-level diet quality. Findings from this study can help us to address modifiable targets of intervention in the home to improve diet quality.

Early Exposure to Recommended Calorie Delivery in the Intensive Care Unit Is Associated With Increased Mortality in Patients With Acute Respiratory Distress Syndrome.

BACKGROUND: The Intensive Nutrition in Acute Lung Injury: Clinical Trial (INTACT), designed to evaluate outcomes of calorie delivery from acute respiratory distress syndrome (ARDS) diagnosis through hospital discharge, was stopped due to higher mortality in the intervention group. Post hoc analysis found timing and dose of calorie delivery influenced mortality. The objective of this retrospective cohort study was to determine if early vs late calorie exposure changed the hazard of death among a larger sample of patients with ARDS. METHODS: Adult patients who met the eligibility criteria for INTACT but did not participate were included. Daily calorie delivery was collected from the date INTACT eligibility was determined to extubation or death. Cox proportional hazards regression was used to model the relationship between hazard of hospital death with average calorie exposure received over increasing study days and after day 7. RESULTS: A total of 298 patients were included; overall mortality was 33%. Among patients who remained intubated at 1 week (n = 202), higher kcal/kg received from intensive care unit (ICU) days 1-6 increased hazards of subsequent death on days 7+ (hazard ratio [HR], 1.04; 95% confidence interval [CI], 1.01-1.06); kcal/kg received after ICU day 7 decreased the hazards of death on day 7+ (HR, 0.53; 95% CI, 0.33-0.84). CONCLUSIONS: Higher calorie exposure between ICU days 1 and 7 was associated with higher subsequent hazard of mortality, and provision of high-calorie exposure after day 8 decreased the hazards of death.

Guidelines for the Provision and Assessment of Nutrition Support Therapy in the Pediatric Critically Ill Patient: Society of Critical Care Medicine and American Society for Parenteral and Enteral Nutrition.

This document represents the first collaboration between two organizations, American Society of Parenteral and Enteral Nutrition and the Society of Critical Care Medicine, to describe best practices in nutrition therapy in critically ill children. The target of these guidelines is intended to be the pediatric (> 1 mo and < 18 yr) critically ill patient expected to require a length of stay greater than 2 or 3 days in a PICU admitting medical, surgical, and cardiac patients. In total, 2,032 citations were scanned for relevance. The PubMed/Medline search resulted in 960 citations for clinical trials and 925 citations for cohort studies. The EMBASE search for clinical trials culled 1,661 citations. In total, the search for clinical trials yielded 1,107 citations, whereas the cohort search yielded 925. After careful review, 16 randomized controlled trials and 37 cohort studies appeared to answer one of the eight preidentified question groups for this guideline. We used the Grading of Recommendations, Assessment, Development and Evaluation criteria to adjust the evidence grade based on assessment of the quality of study design and execution. These guidelines are not intended for neonates or adult patients. The guidelines reiterate the importance of nutritional assessment, particularly the detection of malnourished patients who are most vulnerable and therefore potentially may benefit from timely intervention. There is a need for renewed focus on accurate estimation of energy needs and attention to optimizing protein intake. Indirect calorimetry, where feasible, and cautious use of estimating equations and increased surveillance for unintended caloric underfeeding and overfeeding are recommended. Optimal protein intake and its correlation with clinical outcomes are areas of great interest. The optimal route and timing of nutrient delivery is an area of intense debate and investigations. Enteral nutrition remains the preferred route for nutrient delivery. Several strategies to optimize enteral nutrition during critical illness have emerged. The role of supplemental parenteral nutrition has been highlighted, and a delayed approach appears to be beneficial. Immunonutrition cannot be currently recommended. Overall, the pediatric critical care population is heterogeneous, and a nuanced approach to individualizing nutrition support with the aim of improving clinical outcomes is necessary.