Nutrition in Critically ill Children

The collaborative effort between the American Society of Parenteral and Enteral Nutrition (ESPEN) and the Society of Critical Care Medicine (SCCM) in formulating the ESPEN/SCCM guidelines in 2016 marked a pivotal advancement in critical care nutrition for adults. These guidelines served as a robust foundation for in-depth analyses, particularly in the domain of dogmalysis.

Subsequent to this significant milestone, the focus extended to the pediatric population, leading to the unveiling of the "Best Practices for Nutrition in Critically Ill Children 2017." This release, tailored for children aged over 1 month and under 18 years, reflects a nuanced approach in addressing the distinctive nutritional challenges faced by critically ill pediatric patients.

I have tried to summarise the salient points and common questions that arise in day-to-day rounds in the PICU, and dogma lysis of some of the concepts that are still prevalent among many of us in the Pediatric ICU.

Literature review

The guidelines were formulated after reviewing the following literature.

1. 16 randomized controlled trials
2. 37 cohort studies
3. The above studies were used to answer eight preidentified questions for eight practice areas. I like these guidelines since they have more practical approach and based on day to day questions and dicsussion.

Tip-These can be used to stop the argument occasionally with surgeon. (But use the tip with caution)

Guidelines Limitations

The following limitation can be noted.

1. The guideline is based on general consensus among a group of professionals.
2. The literature used has variations in study design, small sample size, and patient heterogeneity, There is a variability in disease severity amongst the sample.
3. There is a lack of information on baseline nutritional status.
4. There is no high-quality statistical data available for analysis.

These are some of the questions that the guideline answers or points that are recommended.

1 A. What is the Impact of nutritional status on outcomes in critically ill children

Quality of evidence: very low

Grade of recommendation: strong

Answer:

Malnutrition, including obesity, is associated with following adverse clinical outcomes.

• longer periods of ventilation,
• higher risk of hospital-acquired infection,
• longer PICU and hospital stay, and
• increased mortality.

Do this for all PICU admissions

1. Detailed nutritional assessment within 48 hr of admission.
2. Re-evaluate at least weekly throughout hospitalization.

1 B. What are the best practices for screening and identifying patients with malnutrition or at risk of malnutrition in the PICU?

Quality of evidence: very low
Grade of recommendation: strong

Answer:

• Weight and height/length to be measured on admission to the PICU,
• Z scores for BMI  for age and weight-for-length should be recorded for ages < 2 yr
• Weight-for-age, in case accurate height is not available, should be used to screen for nutrition status.
• In children under the age of 36 months, head circumference must be documented.

Additional Points

BMI z scores may additionally be useful to screen for patients at risk of poor outcomes in the PICU

2 A. What is the recommended energy requirement for critically ill children?

Predicting calorie assessment in critically ill pediatric patients has been a perplexing journey, marked by varying numbers and explanations. The gold standard, indirect calorimetry (IC), remains out of reach in many units, mirroring my own experience in training and subsequent work settings where its provision was absent.

Quality of evidence: low
Grade of recommendation: weak

Indirect calorimetry (IC) to be used to determine energy expenditure (REE) and guide prescription of the daily energy requirements

2 B. How to determine energy requirement in the absence of indirect calorimetry?

The guidelines, however, outline steps to take when IC is not available. This disjunction between the ideal and the practical underscores the ongoing challenge of ensuring precise nutritional management for critically ill individuals. Both IC and optional steps have a low quality of evidence.

Quality of evidence: very low
Grade of recommendation: weak

If IC measurement is not available

Use the Schofield or Food Agriculture Organization/World Health Organization/United Nations University equations “without” the addition of stress factors to estimate energy
expenditure in PICU.

Note

Many of us have been using the Harris benedicts equation to estimate calorie requirement. The guideline recommends against the use of the Harris-Benedict equations and the RDAs to determine energy requirements in critically ill children.

What is the Harris-Benedict equation?

The body's basal metabolic rate (BMR) represents the energy needed for essential metabolic functions like respiration, thermogenesis for maintaining body temperature, and digestion. This energy expenditure occurs at rest, devoid of any additional activity.

It exclusively sustains vital organ functions, encompassing the heart, lungs, nervous system, kidneys, liver, intestine,, muscles, and skin. So, Basal metabolic rate (BMR) is the amount of calories burnt during an inactive period such as sleep. It can be calculated from height, weight, age, and gender.

Harris-Benedict equation estimates the BMR in step 1 and then in step 2, it estimates the total energy expenditure for a particular activity level, and the calorie requirement for that individual for that activity level.

BMR calculation for men

BMR = 66.47 + ( 13.75 x weight in kg ) + ( 5.003 x height in cm ) - ( 6.755 x age in years )

BMR calculation for women

BMR = 655.1 + ( 9.563 x weight in kg ) + ( 1.850 x height in cm ) - ( 4.676 x age in years )

The Harris-Benedict Equation uses BMI and calculates the total energy expenditure (TEE)  for the given activity by using the activity factor as follows.

Activity level	Total energy expenditure (TEE)
Sedentary or light activity TEE	BMR x 1.53
Active or moderately active TEE	BMR x 1.76
Vigorously active	BMR x 2.25

2C. What should be the target energy intake in critically ill children

Quality of evidence: low

The recommendation emphasizes the aim of delivering a minimum of two-thirds of the prescribed daily energy requirement by the close of the first week in the Pediatric Intensive Care Unit (PICU).

Recognizing and managing energy deficits within this initial critical week may correlate with favorable clinical and nutrition outcomes.

The guidance underscores a focus on individualized energy requirements, prompt initiation, and successful achievement of energy targets. This multifaceted approach seeks to avert unintended cumulative caloric deficits or excesses, fostering optimal nutritional support in the PICU setting.

3A. What should be the minimum recommended protein requirement for critically ill children?

Quality of evidence: moderate
Grade of recommendation: strong

Minimum recommended protein intake is 1.5 g/kg/d.

Higher than this threshold is shown to prevent cumulative negative protein balance in RCTs. The optimal protein intake required to attain a positive protein balance may be higher than this minimum threshold in sick children.

Negative protein balance may result in loss of lean muscle mass, which has been associated with poor outcomes in critically ill patients.

Higher protein intake may be associated with lower 60-day mortality in mechanically ventilated children. (Observational study )

3B. What is the optimal strategy to deliver protein in the PICU?

Quality of evidence: moderate
Grade of recommendation: weak

Based on the findings from randomized trials, the suggestion is to initiate protein provision early in the trajectory of critical illness, aiming to meet protein delivery goals and foster a positive nitrogen balance.

Notably, observational studies have indicated that achieving a higher proportion of the protein goal correlates with positive clinical outcomes. This recommendation underscores the significance of early and effective protein delivery in optimizing patient responses during critical illness.

3C. How to set protein delivery goals in PICU?

Quality of evidence: moderate
Grade of recommendation: strong

Nothing is clarified here, unfortunately. What is the optimal protein dose that will improve clinical outcomes is not known. RDA values were developed for healthy children and often underestimate the protein needs during critical illness.

The optimal protein dose associated with improved clinical outcomes is not known. We do not recommend the use of RDA values to guide protein prescription in critically ill children. These values were developed for healthy children and often underestimate the protein needs during critical illness.

4A. Should we start enteral nutrition in critically ill children?

Quality of evidence: low
Grade of recommendation: strong

Yes, as per guidelines, enteral nutrition is the preferred mode in critically ill children over any other route.

Who can receive it?

1. Kids with medical diagnoses
2. Kids with surgical diagnoses
3. Those receiving vasoactive medications for shock.

What are common barriers to EN in the PICU?

I can not agree to this more than anything. The common interruptions are

• Delayed initiation,
• Interruptions due to perceived intolerance
• Prolonged fasting around procedures.

Identifying these Interruptions to EN and minimizing them to achieve nutrient delivery goals is the key.

4B. What are the benefits of enteral nutrition in sick children?

Quality of evidence: low
Grade of recommendation: weak

The administration of nutrients via Enteral Nutrition (EN) has proven advantageous for maintaining gastrointestinal mucosal integrity and promoting motility.

Notably, early commencement of EN within the initial 24-48 hours of Pediatric Intensive Care Unit (PICU) admission, coupled with achieving up to two-thirds of the nutrient goal within the first week of critical illness, has demonstrated a positive correlation with enhanced clinical outcomes, as evidenced by large cohort studies.

This highlights the significance of timely initiation and effective nutrient delivery through EN in contributing to improved patient responses during critical illness.

5A. What is the best method for advancing EN in the PICU population?

Quality of evidence: low
Grade of recommendation: weak

Straightforward guidance is not provided here. Again the circus of words "Use of a stepwise algorithmic approach to advance EN in children admitted to the PICU". The stepwise algorithm must include bedside support to guide the detection and management of EN intolerance and the optimal rate of increase in EN delivery. It means get your stuff right your way.

5B. What is the role of a nutrition support team or a dedicated dietitian in optimizing nutrition?

Quality of evidence: low
Grade of recommendation: weak

The nutrition support team, including a dedicated dietitian, should be included in the PICU team, to facilitate timely nutritional assessment and optimal nutrient delivery.

6A. What is the best site for enteral nutrition delivery - gastric or small bowel?

Quality of evidence: low
Grade of recommendation: weak

The preferred route is gastric, however, in select patients, the postpyloric route may be used in those who are unable to tolerate gastric feeding or those at high risk for aspiration.

Their data is Insufficient to make recommendations regarding the use of continuous vs intermittent gastric feeding.

6B. When to initiate enteral nutrition?

Quality of evidence: low
Grade of recommendation: weak

• Enteral nutrition should be initiated in all critically ill children unless contraindicated.
• Consider early initiation, within the first 24–48 hr after admission to the PICU, if not contraindicated.

7A. What is the indication for and optimal timing of PN in critically ill children?

Quality of evidence: moderate
Grade of recommendation: strong

There are 3 main questions we all face in PICU. 7A and 7B try to answer those questions.

• Whether to use of PN as a supplement to EN in case we cannot increment it further?
• When should we start PN?
• What is the targeted for macronutrient goal'

There is no data to answer any of these firstly in these guidelines. However, they have quoted the following study.

3-center RCT, PEPaNIC trial - Early versus Late Parenteral Nutrition in the Pediatric Intensive Care Unit.

• The trial addresses the timing of supplemental PN in critically ill children, the group with late initiation of PN on day 8, demonstrated better outcomes in terms of fewer new infections and shorter length of PICU stay when compared with the early initiation group receiving PN within 24 hours of admission.
• Also, the late PN group was likely to have an earlier live discharge from the PICU, shorter duration of mechanical ventilation, and lower odds of renal replacement therapy.

based on this, my take-home message is PN should be considered when EN is not feasible or is contraindicated but don't be in a hurry to start it.

7B. Is there a role of parenteral nutrition as a supplement to inadequate EN?

Quality of evidence: low
Grade of recommendation: weak

No PN in the first week

Stepwise advancement of nutrient delivery via the enteral route and delaying commencement of PN. The role of supplemental PN to reach a specific goal for energy delivery is not known.

The time when PN should be initiated to supplement insufficient enteral nutrition is unknown. Based on the above RCT, supplemental PN should be delayed until 1 week after PICU admission in patients with normal baseline nutritional state and low risk of nutritional deterioration.

PN in the first week

Children who are unable to receive any EN during the first week in the PICU can be started on PN. In patients who are severely malnourished or at risk of nutritional deterioration, PN may be supplemented in the first week if they are unable to advance volumes of EN.

8. Is there any role of immunonutrition in critically ill children?

Quality of evidence: moderate
Grade of recommendation recommendation: strong

None.

Summary

1. Nutritional assessment within 48 hours of admission, re-evaluate weekly.
2. Use z scores for BMI, weight-for-length, weight-for-age, and HC for assessment.
3. Use Indirect calorimetry if available. Don't use Harris-Benedict equations, or RDAs as guides to requirements.
4. Initiate enteral nutrition within 24 to 48 hours unless contraindicated. Achieve at least 2/3rd of calories by the end of 1st week unless contraindicated. The minimum protein intake should be 1.5 g/kg/d. 
5. Prefer enteral nutrition over parenteral, there is no data on which is better - gastric or post-pyloric.
6. Don't give immuno-nutrition, it doesn't help.

Myths in ICU nutrition 

In my exploration of guidelines, I stumbled upon Paul E. Marik's enlightening post dissecting prevalent myths surrounding ICU nutrition. As an advocate of dogma lysis, I feel compelled to share these insights, recognizing their relevance not only in the adult sphere but equally so in the pediatric population.

The critical examination of established beliefs in nutrition aligns seamlessly with my experiences and practices in pediatric critical care settings.

• Myth no. 1: Starvation or undernutrition is “okay” -wrong
• Myth no. 2: Parenteral nutrition is safe -wrong
• Myth no. 3: En contraindicated with vasopressors -wrong
• Myth no. 4: Early enteral nutrition is not important in patients receiving mechanical ventilation - wrong
• Myth no. 5: En is contraindicated with high gastric residual volume -wrong
• Myth no. 6: Postpyloric feeding reduces the risk of aspiration -wrong
• Myth no. 7: En is contraindicated in patients without bowel sound  and/or a postoperative ileus - wrong
• Myth no. 8: En is contraindicated following gi surgery - wrong
• Myth no. 9: En is contraindicated in patients with an open abdomen - wrong
• Myth no. 10: En is contraindicated in patients with pancreatitis - Wrong