Malnutrition and inadequate feedings are a common challenge for dietitians in the critical care setting. Both can result in poor clinical outcomes including, but not limited to, impaired immune response, higher costs, poor wound healing, worsening systemic inflammation, and increases in both mortality and length of stay (LOS).1-2
Nutrition therapy continues to come to the forefront to reduce these effects. Early initiation and adequacy of enteral feeds have been shown to prevent oxidative cellular injury, preserve gut integrity, and alleviate the metabolic stress response.1 The benefits of early and adequate nutrition support cannot be disregarded when it comes to patients in the intensive care unit (ICU). How do we as dietitians accomplish such a difficult task?
Volume-Based Feeding (VBF)
VBF is a prescribed daily total goal volume, rather than the traditional fixed hourly rate. Unlike rate-based feeding (RBF), VBF accounts for interruptions, delays, and frequent nil per os (NPO) events.2 This is accomplished through a “catch-up” period, where the nurse would subtract the remaining volume needed to be fed and divide it over the remaining hours until the 24-hour period is over.1
Literature indicates that feedings are often intermittently stopped in up to 85% of critically ill patients due to feeding intolerance or procedures/surgeries.3 Energy and protein delivery are further compromised by initiation of a low starting rate, slow increases to goal, and hesitancy of providers to resume enteral nutrition (EN) at goal rate after a period of holding feeds.1 Unlike RBF, VBF allows dietitians and providers a greater chance of achieving the ASPEN/SCCM recommendations of meeting greater than 80% of prescribed nutrition to critically ill patients.4
Historically, RBF has been based on the dietitian’s recommendations with little accountability from other members of the critical care team. VBF allows for a multidisciplinary approach, especially between the dietitian and nurse. Allowing for a VBF approach empowers the nurses to initiate quicker start-ups, titrate feeding rates to make up for lost time while EN was held, better handling of gastric residual volumes (GRVs), and frequency of flushes.4
Protocols can also be established for set rates and formulas based on a patient’s BMI, gender, electrolyte abnormalities, and whether or not the patient is receiving propofol.1 Once a protocol is in order, the dietitian can then assess and further recommend an individualized care plan, necessitating the appropriate formula, daily goal volume, and possible need of modular proteins.
In Support of Volume-Based Feeding
Several studies have found that, with a VBF protocol in place, patients had a higher likelihood of receiving greater than 80% of their energy and protein recommendations.1-3,5 Of course, this is the main goal that the VBF protocol is out to accomplish.
Contrary to the belief that high catch-up rates would increase the risk of hyperglycemia, many studies found that not to be the case.1,5 Holyk et al utilized a maximum catch-up rate of 150 ml/hr for both gastric and jejunal feeds and found that none of their patients who had received the maximum rate experienced moderate hyperglycemia.1
Furthermore, there was no noted difference for average blood glucose when comparing RBF to VBF protocols.1 Patients in the study by Prest et al went a step further and demonstrated better glycemic control for their study patients on a VBF protocol.5 Between the two feeding regimens, no differences had been noted in regards to diarrhea or tube dislodgment.2
The Importance of a Multidisciplinary Approach
Implementation of a VBF protocol involves a multidisciplinary approach with frequent education and training offered to staff. Nursing education is imperative for this to be a successful nutrition support option. After starting their research, Sachdev et al found initial noncompliance to the protocol amongst nursing staff. Therefore, they implemented increased frequency of nursing communication and education, reinforcement at morning huddles, and education for all new nursing staff.2 Other strategies to empower nurses on VBF protocols could include “how to” booklets at each bedside, one-on-one education with feedback, and providing a place for nursing to document enteral feeding deficits and corrections.3
Transitioning to a VBF protocol has shown to be well-tolerated, safe, and effective. With that in mind, registered dietitians working in the critical care setting can review the research and determine the feasibility of instituting their own program.
Kimberly Brown, MS, RD, LD is a clinical dietitian currently working at a 1000+ bed facility in Oklahoma. She has spent a majority of her career working in intensive care, including Level 1 trauma/burn, cardiothoracic, and medical ICU. She is passionate about nutrition support and ensuring that each patient’s nutritional needs are being met. In her free time, she enjoys running, traveling, painting, and keeping up with her three children.
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Holyk A, Belden V, Sirimaturos M, Chiles K, et al. Volume-based feeding enhances enteral delivery by maximizing the optimal rate of enteral feeding (FEED MORE). JPEN J Parenter Enteral Nutr. 2019;0:1-9.
Sachdev G, Backes K, Thomas BW, Sing RF, Huynh T. Volume-based protocol improves delivery of enteral nutrition in critically ill trauma patients. JPEN J Parenter Enteral Nutr. 2019;0:1-6.
Brierley-Hobson S, Clarke G, O’Keeffe V. Safety and efficacy of volume-based feeding in critically ill, mechanically ventilated adults using the ‘protein & energy requirements fed for every critically ill patient every time’ (PERFECT) protocol: a before-and-after study. Crit Care. 2019;23:105.
McClave SA, Taylor BE, Martindale RG, et al. Guidelines for the provision and assessment of nutrition support therapy in the adult crtically 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.
Prest PJ, Justice J, Bell N, McCarroll R, Watson CM. A volume-based feeding protocol improves nutrient delivery and glycemic control in a surgical trauma intensive care unit. JPEN J Parenter Enteral Nutr. 2019;0:1-9.