It’s an unbelievable honor to have Dr. Sam Tisherman come and join our critical care faculty at the Shock Trauma Center and University of Maryland. Â Dr. Tisherman is a Professor of Surgery & Critical Care and heavily involved our fellowship education. Â He has won numerous education awards, and was inducted into the University of Pittsburgh School of Medicine’s Academy of Master Educators. Â He is well-known for his research in traumatic shock and cardiac arrest – and is responsible for the development of Emergency Preservation and Resuscitation (EPR).
A true intensivist interested in all things critical care, Dr. Tisherman came to discuss an incredibly important (and often overlooked) topic: Nutrition.
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Nutrition assessment
- Traditional nutrition markers such as albumin, prealbumin, and retinol-binding protein have a limited role in the ICU
- Inaccurate measurements are partly due to the fact that most of these are acute phase reactants!
Timing of Nutrition
- Start feeds within 24-48 hrs – nutrition decreases infection rates, length of stay, and possibly mortality.
- Beware feeding the patient too early.  Shocked patients or those in the  resuscitation phase can develop bowel ischemia with feeding.
- Feeding patients on low-dose pressors is probably ok.
- Early fascial closure and less fistula formation has been found in patients who receive early feeding with a traumatic open abdomen.
- Feeding early in pancreatitis is better for gut epithelium integrity and can reduce complication rates.
Caloric and Protein Goals
- Protein intake: 1-1.2 g/kg/d to keep nitrogen balance + for wound healing and immune system function.
- Caloric goals are 25-30 cal/kg/day
- Harris Benedict equation calculates energy expenditure based on age, gender, weight, and height, and takes into account stress factor.
- Indirect calorimetry measures carbon dioxide production directly
- No difference in mortality shown between under feeding and full feeding.
Feeding Obese Patients in the ICU
- Obese patients may require less calories per Kg, but higher protein intake per Kg.
- Calories: approximately 25cal/kg/d
- Protein: approxmiately1.5-2 g/kg/d
Location – Enteral vs parenteral
- Contraindications for enteral feeding: shock, GI obstruction, Â short gut, fistula, Â ileus.
- Jejunostomy compared to gastrostomy, has higher risk of obstruction and torsion.
- G tube indicated if its use us anticipated for more than 6 weeks.
- Diarrhea in patients receiving enteral feeding warrants meds review( abx, laxatives), investigation of fecal impaction, kwashiorkor.
Enteral Access
- Bowel sounds, flatus, and bowel movement are overrated parameters for post operative feeding.
- Consider post-pyloric feeding tube for vomiting despite pro-kinetic and high risk for aspiration.
- No difference between post-pyloric and gastric in vent associated conditions.
- In acute pancreatitis, early enteral feeding is recommended. Still debatable whether  gastric or post-pyloric/ligament of Treitz is better.
Evidence about Residuals & Feeding
- Prone positioning does not increase residuals in one study  but there is a higher risk of regurgitation.
- Multi-center trial in France showed no difference in VAP upon not checking residuals. (Reignier et al., 2013)
Parenteral Feeding
- TPN is indicated for anticipated NPO more than a week, Malnourished with expected GI tract surgery , and when enteral feeding is not feasible.
- Cons of TPN: Central venous access, fatty liver, cholestasis, cholelithiasis, Â gut villous atrophy.
- No difference found between early vs. late TPN.
- High protein nutrition did not improve outcomes.
- High omega-3 nutrition did not improve survival, Â Â ventilation duration.
Worth Noting…
- Estimated protein loss with CRRT is 10-15 gm a day.
- In liver failure malnutrition worsen ascites.
- Liver failure specific nutrition with aromatic amino acids may be indicated for refractory encephalopathy.
- MUST READ: STC Clinical Nutrition Review
- Van zanten AR, Sztark F, Kaisers UX, et al. High-protein enteral nutrition enriched with immune-modulating nutrients vs standard high-protein enteral nutrition and nosocomial infections in the ICU: a randomized clinical trial. JAMA. 2014;312(5):514-24. [PubMed Link]
- Reignier J, Mercier E, Le gouge A, et al. Effect of not monitoring residual gastric volume on risk of ventilator-associated pneumonia in adults receiving mechanical ventilation and early enteral feeding: a randomized controlled trial. JAMA. 2013;309(3):249-56. [PubMed Link]
- Mcclave SA, Martindale RG, Rice TW, Heyland DK. Feeding the critically ill patient. Crit Care Med. 2014;42(12):2600-10. [PubMed Link]