Among the college questions, there is an entire range which all vaguely follow the pattern of "how would you feed this patient?" For example, Question 9 from the second paper of 2001 has specifically asked for strategies to manage the inadequate delivery of nutritional support in a trauma patient (who for some unspecified reason is only receiving 25% of their goal calories). In the process of constructing this summary, my main sources were the Canadian Clinical Practice Guidelines, ESPEN Guidelines (2009) and the ASPEN Guidelines (2015). These are large documents, and written in an almost intentionally inaccessible manner. The time-poor candidate may be better served by the more recent summary review articles, such as the 2015 paper by Ridley Gantner and Pellegrino.
In short, the guidelines for ICU nutrition can be summarised as strongly favouring enteral nutrition, with an emphasis on earlier delivery of more calories. Protein seems to be the most important macronutrient (1.2-2.0g/kg/day). Strategies to achieve nutritional goals include protocolised feeding, minimisation of interruptions to feeding, use of prokinetics and upright posture, returning gastric residuals under 250ml, use of post-pyloric feeding, and the supplementation of inadequate or poorly tolerated enteric nutrition with some TPN.
The most important literature on this topic has been summarised by Chris Nickson from LITFL in this excellent CCC entry. Briefly, exam candidates need to be familiar with the following landmark papers.
Links to chapters relevant to each question are offered.
- Set up nutrional goals
- Use indirect calorimetry if available; or estimate using 25kcal/kg/day
- No single predictive equation has much of an advantage over any others
- EN is preferred to start with (safety, price, etc) unless contraindicated
- No mortality benefit, whether you use EN or PN
- No major advantage to using nasojejunal feeding
- Start within 48 hours
- Start at 30ml/hr and escalate (no strong evidence for this incremental approach)
- Minimal "gut-protective dose" is not well established
- 10ml/hr is safe in well-nourished patients
- To be sure, 50-65% of goal rate is probably required
- No strong evidence that meeting 100% energy goals improves mortality
- Weak evidence that this may be actually harmful in well-nourished patients
- More likely, 100% goal rate is more appropriate in the recovery stages of critical illness
- Earlier in the acute illness 33-66% of goal rate may be appropriate for the premorbidly well-nourished patient
Management of feed intolerance
- Minimise interuptions to enteral nutrition, and use higher make-up rates
- Return higher gastric aspirates than you'd normally be comfortable with
- Sit the patient up to 45º
- Start some pro-kinetic agents (metoclopramide and erythromycin)
- Advance the NGT into the jejunum (may not help)
- If goals remain unmet after ~48 hours, add PN as a supplement
- A well-nourished patient can wait 7 days without EN or TPN
- A malnourished patient can't wait (immedaitely begin)
- Start at 80% rate
- Start pre-operatively for the malnourished surgical candidates
- Add PN to inadequate EN to make up the lost nutrition
Rice, Todd W., et al. "A randomized trial of initial trophic versus full-energy enteral nutrition in mechanically ventilated patients with acute respiratory failure." Critical care medicine 39.5 (2011): 967.
Heighes, Philippa T., Gordon S. Doig, and Fiona Simpson. "Timing and Indications for Enteral Nutrition in the Critically Ill." Nutrition Support for the Critically Ill. Springer International Publishing, 2016. 55-62.
McClave, Stephen A., et al. "Guidelines for the Provision and Assessment of Nutrition Support Therapy in the Adult Critically Ill Patient Society of Critical Care Medicine (SCCM) and American Society for Parenteral and Enteral Nutrition (ASPEN)." Journal of Parenteral and Enteral Nutrition 40.2 (2016): 159-211.
Mentec, Hervé, et al. "Upper digestive intolerance during enteral nutrition in critically ill patients: frequency, risk factors, and complications." Critical care medicine 29.10 (2001): 1955-1961.
Heyland, Daren K., et al. "Canadian clinical practice guidelines for nutrition support in mechanically ventilated, critically ill adult patients." Journal of Parenteral and Enteral nutrition 27.5 (2003): 355-373.
Montejo, J. C., et al. "Gastric residual volume during enteral nutrition in ICU patients: the REGANE study." Intensive care medicine 36.8 (2010): 1386-1393.
Poulard, Fanny, et al. "Impact of Not Measuring Residual Gastric Volume in Mechanically Ventilated Patients Receiving Early Enteral Feeding A Prospective Before–After Study." Journal of Parenteral and Enteral Nutrition 34.2 (2010): 125-130.
Desachy, Arnaud, et al. "Initial efficacy and tolerability of early enteral nutrition with immediate or gradual introduction in intubated patients." Intensive care medicine 34.6 (2008): 1054-1059.
Juvé-Udina, Maria-Eulàlia, et al. "To return or to discard? Randomised trial on gastric residual volume management." Intensive and Critical Care Nursing 25.5 (2009): 258-267.
Bing, Guo. "Gastric residual volume management in critically ill mechanically ventilated patients: A literature review." Proceedings of Singapore Healthcare (2015): 2010105815598451.
Nguyen, Nam Q. "Pharmacological therapy of feed intolerance in the critically ills." World journal of gastrointestinal pharmacology and therapeutics 5.3 (2014): 148.
Marino, L. V., et al. "To determine the effect of metoclopramide on gastric emptying in severe head injuries: a prospective, randomized, controlled clinical trial." British journal of neurosurgery 17.1 (2003): 24-28.
Nguyen, Nam Q., et al. "Erythromycin is more effective than metoclopramide in the treatment of feed intolerance in critical illness*." Critical care medicine 35.2 (2007): 483-489.
Fraser, R. J., A. M. Deane, and Marianne J. Chapman. "Prokinetic drugs for feed intolerance in critical illness: current and potential therapies." Critical Care and Resuscitation 11.2 (2009): 132.
Singer, Pierre, et al. "ESPEN guidelines on parenteral nutrition: intensive care." Clinical nutrition 28.4 (2009): 387-400.
van Zanten, Arthur RH, et al. "Enteral glutamine supplementation in critically ill patients: a systematic review and meta-analysis." Critical Care 19.1 (2015): 1-16.
Oldani, Massimo, et al. "Glutamine Supplementation in Intensive Care Patients: A Meta-Analysis of Randomized Clinical Trials." Medicine 94.31 (2015).
Wernerman, Jan. "How to understand the results of studies of glutamine supplementation." Critical Care 19.1 (2015): 1-3.
van Zanten, Arthur RH, Zandrie Hofman, and Daren K. Heyland. "Consequences of the REDOXS and METAPLUS Trials The End of an Era of Glutamine and Antioxidant Supplementation for Critically Ill Patients?." Journal of Parenteral and Enteral Nutrition (2015): 0148607114567201.
Heyland, Daren, et al. "A randomized trial of glutamine and antioxidants in critically ill patients." New England Journal of Medicine 368.16 (2013): 1489-1497.
Van Zanten, Arthur RH, 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 312.5 (2014): 514-524.
Ridley, Emma, Dashiell Gantner, and Vincent Pellegrino. "Nutrition therapy in critically ill patients-a review of current evidence for clinicians." Clinical Nutrition 34.4 (2015): 565-571.
Singer, Pierre, et al. "The tight calorie control study (TICACOS): a prospective, randomized, controlled pilot study of nutritional support in critically ill patients." Intensive care medicine 37.4 (2011): 601-609.
Casaer, Michael P., et al. "Early versus late parenteral nutrition in critically ill adults." N Engl J Med 365.6 (2011): 506-517.
Heidegger, Claudia Paula, et al. "Optimisation of energy provision with supplemental parenteral nutrition in critically ill patients: a randomised controlled clinical trial." The Lancet 381.9864 (2013): 385-393.
Doig, Gordon S., et al. "Early parenteral nutrition in critically ill patients with short-term relative contraindications to early enteral nutrition: a randomized controlled trial." Jama 309.20 (2013): 2130-2138.
Davies, Andrew R., et al. "A multicenter, randomized controlled trial comparing early nasojejunal with nasogastric nutrition in critical illness*." Critical care medicine 40.8 (2012): 2342-2348.
Harvey, Sheila E., et al. "Trial of the route of early nutritional support in critically ill adults." New England Journal of Medicine 371.18 (2014): 1673-1684.
Andrews, Peter JD, et al. "Randomised trial of glutamine, selenium, or both, to supplement parenteral nutrition for critically ill patients." Bmj 342 (2011): d1542.
Braunschweig, Carol A., et al. "Intensive Nutrition in Acute Lung Injury A Clinical Trial (INTACT)." Journal of Parenteral and Enteral Nutrition 39.1 (2015): 13-20.