September 2016 Issue
EN/PN Nutrition: Nutrition Support for the Critically Ill
By Mandy L. Corrigan, MPH, RD, CNSC, FAND
Vol. 18 No. 9 P. 18
Overview of the New Guidelines and Tips on How to Implement Them
In February, the Society for Critical Care Medicine (SCCM) and the American Society for Parenteral and Enteral Nutrition (ASPEN) released an update to the 2009 nutrition guidelines for critically ill patients.1 Nutrition support clinicians have long been waiting for the new guidelines, published in the Journal of Parenteral & Enteral Nutrition.
The guidelines are consensus recommendations from SCCM and ASPEN drawn from current research whose purpose is to guide the care of critically ill patients requiring nutrition support. Their main focus is on adult patients in a surgical or medical ICU who are expected to remain in the ICU beyond 48 to 72 hours. There are various ICU nutrition topics discussed in the 2009 and current edition, but the new guidelines also expand on specific patient conditions such as organ failure, pancreatitis, surgical populations, open abdomen and sepsis, the chronically critically ill, and management of the obese patient. The new guidelines are intended to reach dietitians, physicians, nurses, and pharmacists to improve their role in caring for the nutritional needs of these patient populations. As such, it's important for all dietitians practicing in acute care settings to become familiar with the updated guidelines and the evidence that supports their recommendations.
"The guidelines provide guidance to RDNs as we strengthen our position in the multidisciplinary ICU team," says Beth Taylor, DCN, AP-RD, LD, CNSC, FCCM, a colead author of the guidelines and research/education specialist and surgical/trauma unit nutrition support specialist at Barnes-Jewish Hospital of the Washington University School of Medicine in St. Louis.
This article will discuss some of the highlights, changes, and new additions to the guidelines and offer feedback from those working with critically ill patients.
Evaluating the Research to Form the New Guidelines
The authors make it clear that the guidelines don't ensure beneficial outcomes and shouldn't take the place of making clinical judgments and decisions based on patients' individual medical needs. So while it's important for dietitians to know what the research says, they should make decisions based on individual patients' needs as part of the medical team.
The research studies the authors reviewed and included in the analysis were published before December 31, 2013. However, the authors do mention studies published after this cutoff date in the discussion sections within the guidelines. The way the authors evaluated the quality of the research in 2009 differed from the way they evaluated it to develop the updated guidelines. They evaluated the quality of research using a method called GRADE (Grading of Recommendations, Assessment, Development, and Evaluation). When GRADE couldn't be used because of the way in which certain studies were designed, the authors made suggestions based on consensus and expert opinion.
What's New in the Guidelines?
Nutrition Risk Determination
Both the 2009 and 2016 guidelines for the critically ill state that screening for nutrition risk should be completed on every ICU patient, but the concept of addressing both nutrition status and disease severity is a new recommendation based on expert opinion that's been included in the update. Screening tools for determining nutrition risk now include the nutritional risk screening (NRS 2002) or the NUTRIC (Nutrition Risk in Critically Ill) score to establish high or low nutrition risk. Hospitals across the United States haven't had a standardized nutrition risk assessment tool to use with patients, so their methods varied widely. The concept of linking disease severity with nutrition status has generated much discussion among clinical RDs regarding their current methods of evaluating nutrition risk. "We haven't done NUTRIC score or NRS 2002 yet, but we've been discussing it," says Kris Mogensen, MS, RD, LDN, CNSC, team leader dietitian at Brigham and Women's Hospital in Boston.
Many RDs probably are in the same phase of discussing current nutrition risk, and evaluating practices and the use of the NRS 2002 or NUTRIC score. The authors again reinforce that surrogate biochemical markers such as albumin, prealbumin, retinol-binding protein, and transferrin aren't validated markers for assessing nutrition status. They agree that the outcome of nutrition screening, in accordance with NRS 2002 or NUTRIC scores, is associated with determining when to initiate parenteral nutrition.
Gastric Residual Volumes
Over the years, the bedside practices used for placing enteral nutrition (EN) orders on hold, based on gastric residual volumes (GRVs), measurements of stomach contents, have varied. Typically, a nurse attaches a syringe to the end of the feeding tube, withdraws the contents of the stomach, and measures the volume. Unfortunately, the practice of measuring GRVs as a way to assess tolerance to EN feeds is a common practice that isn't evidence based. The new guidelines recommend that dietitians and other health care practitioners do not use GRVs routinely for patients receiving EN based on the evidence from three studies.2-4 The elimination of performing routine GRVs has been shown to improve delivery of EN without compromising patient safety. The authors include recommendations for monitoring tolerance to EN in place of administering routine GRVs.1 Understanding that this is a change from historical ICU practice, the authors suggest that if GRVs are still used, health care practitioners shouldn't place EN orders on hold when the GRV is <500 mL.
"I do appreciate the authors recommending discontinuing the practice of routine GRV checks," says Stephanie Dobak, MS, RD, LDN, CNSC, a clinical dietitian at Thomas Jefferson University Hospital in Philadelphia. "They acknowledge it's a big practice change and therefore offer a threshold of 500 mL if GRVs continue to be checked. Our neurocritical care units are no longer routinely checking GRVs, saving nursing time and resources."
Enteral Formula Selection
The 2016 guidelines also include new recommendations for selecting enteral formulas. The guidelines endorse the use of a standard polymeric formula for patients receiving EN in the ICU. Due to the high cost of specialty formulas and the insufficient or conflicting data on health outcomes with their use, the choice to use a polymeric formula is commonplace in many institutions. Much of the research on specialty formulas may not apply to all patient populations. And if practitioners use a different product than what was used in a particular study, patients may not experience the same results. Specialty enteral formulas vary slightly in composition from one another. "We are minimalists when it comes to specialty formulas for the most part, which is in line with the new guidelines," Mogensen says.
Studies on specialty formulas completed after the 2009 guidelines were released showed conflicting data on the use of enteral formulas containing omega-3 fish oils in acute respiratory distress syndrome and acute lung injury patients. The once strong recommendation in 2009 to use omega-3 specialty enteral formulas has been downgraded, eliminating such a recommendation. "The evidence to support disease-specific enteral tube feeding formulas [in these patients] just was not there," Dobak says.
One area in which specialty formulas were recommended was in postoperative surgical ICU patients requiring EN. The authors noted that immune-modulating enteral formulas needed to contain both fish oil and arginine based on data showing a decrease in hospital length of stay and reduction in infections.
The authors also discuss the importance of protein as the key macronutrient for ICU patients. They suggest following feeding protocols to increase the delivery of EN (eg, clinical algorithms promoting better initiation and delivery of nutrition, ways to troubleshoot problems), continuing EN in the presence of diarrhea until the cause is determined (eg, infectious, medication related), and achieving blood glucose levels between 150 and 180 mg/dL for the general ICU population.
The new 2016 guidelines will help dietitians and other health care practitioners who work in ICUs incorporate evidence-based practices for daily patient care. Becoming familiar and implementing these recommendations takes a team approach and should be done with the intent to monitor outcomes to recalibrate nutrition practices.
— Mandy L. Corrigan, MPH, RD, CNSC, FAND, is a nutrition support clinician and consultant based in St. Louis.
1. McClave SA, Taylor BE, Martindale RG, 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 (A.S.P.E.N.). JPEN J Parenter Enteral Nutr. 2016;40(2):159-211.
2. Powell KS, Marcuard SP, Farrior ES, Gallagher ML. Aspirating gastric residuals causes occlusion of small-bore feeding tubes. JPEN J Parenter Enteral Nutr. 1993;17(3):243-246.
3. Poulard F, Dimet J, Martin-Lefevre L, et al. Impact of not measuring residual gastric volume in mechanically ventilated patients receiving early enteral feeding: a prospective before-after study. JPEN J Parenter Enteral Nutr. 2010;34(2):125-130.
4. 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):249-256.