Nutrition & Rehabilitation (Verceles)
Summary by Dr. Alison Grazioli
Goal of nutrition in critically ill: balance catabolism of critical illness with anabolism of recovery.
- Provide adequate energy (primarily carbohydrate as body has difficulty mobilizing fatty acids in critically ill)
- Provide adequate protein intake
- Promote physiologic repair
Importance of enteral nutrition
- maintains structural integrity of gut-> prevents bacterial translocation
- maintains gut microbiome
- provides substrates which support immune system and muscle maintenance
- lower infection risk compared to parenteral nutrition
Problems with Enteral Nutrition in ICU
- placement of gastric access
- slow introduction, gradual advancement and frequent interruption can hinder achievement of goal
- intolerances (poor gut mobility/high residuals)
- newer formulations of enteral feeds can be protein inadequate
Feeding into gut directly (naso-jejunal tube) vs. stomach (nasogastric tube):
- No major difference in total energy delivered or in adverse outcomes: PNA, witnessed aspiration, diarrhea, vomiting, length of ICU stay or mortality.
- ASPEN/SCCM 2016 Guidelines: no recommendation to use nasal-jejunal tube for feeding unless high risk for aspiration
Early vs. Delayed enteral feeding
- Early enteral feeding has been associated with lower mortality
- likely no difference in outcomes with early trophic or full feeds so full feeds should be given sooner than later (studied in acute lung injury patients)
How much to feed?
Total Calories:
- MANY (~200) predictive equations in literature some of which correct for pathophysiology. Many are less accurate with obesity.
- Simplistic equations often used in practice
- Most accurate determination of caloric need is indirect calorimetry using a metabolic cart which measures O2 consumption and CO2 produced. Resting energy expenditure (REE) can then be calculated with abbreviated weir equation (REE=3.94xVO2) + 1.1xVCO2). Need patient to be in steady state of energy utilization
Protein intake Goal:
- SCCM/ASPEN 2016 Guidelines: BMI<30 1.2-2.0g/kg actual body weight/day.
- Higher goals in burn and trauma
- regular reassessment of needs required
Barriers to meeting energy goals
-Interventions where feeds held.
-PO intake may have inconsistent delivery
-Documentation errors make intake difficult to assess
-Adequacy of nutrition delivery not often assessed
Strategies to improve tube feed delivery
- incorporation of protocols which detail methods to achieve goals in different ICU scenarios
Early ICU mobility (2-5 days of admission): promising early results
- helps prevent ICU delirium, depression, PTSD, deconditioning, acquired weakness, decreased functional outcomes
- prevents sarcopenia (loss of muscle mass and strength) which can happen as early as 48 hours and can be dramatic
- mobility teams can be used to improve delivery of early mobility with decreased length of hospital stay and can be cost effective
- Data is mixed. Recent RCTs looking at intensive physical therapy vs. standard therapy programs have been surprisingly negative.
- neuromuscular electric stimulation device is a method to exercise muscles in critically ill and is currently being evaluated
Meeting protein and energy targets decreases mortality in critical illness
Likely need to focus on combination of aggressive rehabilitation and optimum nutrition for optimal patient outcomes
