An update on critical care nutrition

Harish Mallapura Maheshwarappa

Director – Institute of Critical Care Medicine. Kauvery Hospitals, Bengaluru

Introduction

This paper was about the vital role of nutrition in better outcomes for critically ill patients. It plays a crucial role for patients in a critical care because most of them must be in a catabolic stress state and SIRS (Systemic Inflammatory Response Syndrome).

The common complications for the patients were

  • Infection
  • Morbidity
  • Multi‑organ failure

Therefore, adequate nutrition was important for attenuating metabolic response to stress which favourably modulate immune responses. This decrease in length of hospital stay, morbidity rate and improvement in patient outcomes.

Nutrition Screening and Assessment

  • Indirect calorimetry – best method
  • Nutrition status of Indian malnourished patients can be assessed by SGA.
  • Initial monitoring of nutrition intervention must be done on daily basis and nutrition plans should be modified accordingly.
  • It is imperative that nutritional assessment is done by well-qualified and trained nutritionists, dedicated to the ICU.
  • Facilitation of nutrition assessment will require good coordination between intensivist and nutritionist.

The period for the right nutrition administration

  • As early as possible
  • At least in first 48 hr
  • HD instability
  • Start after shock resuscitation
  • Tube feed if can’t achieve 50% of requirements in 72 hr.
  • 100% in 7 days
  • Parenteral nutrition only if enteral nutrition cannot be initiated in 7 days

Feeding practices in hemodynamically unstable patients

Clinical monitoring of gut functioning should be started early when the patient is HD stable. Once the patient has been fluid resuscitated and stabilized on declining doses of <2 vasopressors, EN (Enteral Nutrition) may be started cautiously at low rates. EN should be administered within 24–48 hr once the patient is stable with vasopressors.

In persistent shock, early EN should be avoided.

Dosage and Calories

Actual weight

  • Malnourished
  • Normal weight
  • Overweight

Adjusted body weight

  • Obese
  • IBW + 0.25 (ABW – IBW)

Calories

  • 70% carbohydrate and 30% fat. Protein calories should not be calculated
  • Start with 20 Kcal/kg
  • Increase to 25-30 Kcal/kg at the end of week
  • 35 Kcal/kg once stable in a malnurished patient

Protein

  • Critically ill patients – 1.2 to 2 g/kg per day
  • Severe burns – 2.0 g/kg per day

Route of administration

  • Enteral – Preferred (Oral, NG-Nasogastric, NJ (Nasojejunal)
  • Parenteral – only when functional gut not available (TPN, PPN).
  • Combined – no

Enteral Nutrition

  • Decrease the incidence of infection in critically ill patients. Preservation of gut immune function and reduction of inflammation
  • Clinically important and almost statistically significant reduction in mortality
  • Scientific formula feed should be preferred over blenderized feeds to minimize feed contamination.
  • Whenever feasible, closed system ready-to-hang formula feeds should be preferred.
  • Blenderized formulae are more likely to have bacterial contamination than other hospital-prepared diets.
  • Hygienic methods of feed preparation, storage, and handling of both formula feeds and blenderized feeds are necessary.
  • Continuous formula feeding with pumps or gravity bags can be preferably done via fine bore tubes

Contraindications

  • Unresuscitated shock
  • Bowel obstruction
  • Severe and protracted ileus
  • Major upper gastrointestinal bleeding
  • Intractable vomiting or diarrhoea
  • Gastrointestinal ischemia

Post pyloric Feeds (NJ)

  • Prolonged inability to tolerate gastric feedings
  • Gastric outlet obstruction
  • Duodenal obstruction
  • Gastric or duodenal fistula
  • Severe gastroesophageal reflux

Monitoring

GRV (Gastric residual volume)

  • Not strictly recommended
  • Closely monitor in patient with high risk of aspiration
  • Can check every 4-6 hours
  • Reintroduce if less then 500 ml or 50% of feeds
  • Metoclopramide, erythromycin
  • Electrolytes correction

Abdominal distention

Bowel movements

Standard

  • Isotonic to serum
  • Caloric density of approximately 1 kcal/mL
  • Lactose-free
  • Protein content of about 40 g/1000 mL
  • Mixture of simple and complex carbohydrates
  • Long-chain fatty acids
  • Essential vitamins, minerals, and micronutrients

Concentrated

  • Patient requiring volume restriction
  • Hyperosmolar to serum
  • Caloric density 1.5 – 2.0 kcal/mL
  • Dumping syndrome if it is infused rapidly
  • Nausea
  • Shaking
  • Diaphoresis
  • Diarrhea
  • Not in post pyloric feeds

Pre-digested

Content

  • Short chain peptides
  • Simple carbohydrates
  • Short chain triglycerides

Indications

  • Short gut because it is generally well tolerated
  • Digestive defects
  • Failure to tolerate standard enteral nutrition
  • Thoracic duct leak, chylothorax or chylous ascites.

Complications

  • Diarrhoea
  • Metabolic
  • Aspiration

Prevention

  • Backrest elevation
  • Postpyloric feed
  • Motility agents
  • PEG

Disease-Specific Enteral Nutrition

Immunonutrition
Omega-3 fatty acids Anti-inflammatory effect in the lung
Glutamine 15 gm BD

Hyper catabolic patients

Burns

Trauma

Contraindicated in shock
Ornithine ketoglutarateGlutamine precursor
Others
Vitamins and trace alimentsShould be supplemented for all
FibresFor treatment of diarrhoea/constipation
Prebiotics/probioticsAntibiotic-associated diarrhoea.

Hepatic Failure

  • EN should be preferred in patients with acute and/or chronic liver disease, admitted to ICU.
  • No beneficial effects of branched-chain amino acid formulations in critically ill patients with encephalopathy who are receiving first-line luminal antibiotics.
  • Protein supplementation is recommended in liver failure. Protein-energy determination should be based on “dry” body weight or usual weight instead of actual weight.
  • Protein restriction should be avoided in refractory encephalopathy.
  • A whole-protein formula providing 35–40 kcal/kg body weight/day energy intake and 1.2–1.5 g/kg body weight/day protein is recommended.

Traumatic Brain Injury

  • Initiation of EEN after post trauma period (within 24–48 hr of injury), once the patient is HD stable, is recommended.
  • Protein recommendations should be in the range of 1.5–2.5 g/kg/day.
  • Arginine-containing immune-modulating formulations or eicosapentaenoic acid/docosahexaenoic acid supplement with standard enteral formula in TBI patients is recommended.

Acute Kidney Injury

  • Standard enteral formula is recommended for ICU patients with AKI.
  • Protein should not be restricted in patients with renal insufficiency.
  • Daily protein intake should be in the range of 1.2–1.7 g/kg actual body weight in AKI patients.
  • More protein on dialysis patient
  • Provision of adequate non-protein calories should be maintained to achieve total energy intake in patients with AKI.
  • In case of significant electrolyte imbalance, a specialty formulation designed for renal failure should be considered.
  • Low potassium and low phosphate diets can be implemented where corresponding serum levels are high.

Take home message

To eat is a necessity, but to eat intelligently is an art.

 

Dr. Harish Mallapura Maheshwarappa
Director – Institute of Critical Care Medicine

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