October 2017 E-Journal Club
We hosted a marvelous group of trainees in October. It is always wonderful to meet and get to know peers from around the country and world. We share so many of the same professional conundrums, and it is rewarding to be able share ideas of how we approach those challenges.
Our journal club article this month is an investigation into the effects of an enteral feeding formula with a modified fat composition and supplemented with fiber and conditionally essential nutrients on feeding tolerance and nutrition delivery of adult ICU patients.
Qiu C, Chen C, Zhang W, et al. Fat-Modified Enteral Formula Improves Feeding Tolerance in Critically Ill Patients: A Multicenter, Single-Blind, Randomized Controlled Trial. JPEN. 2017 Jul;41(5):785-795.
This was a randomized, single-blind study of 144 adult ICU patients, to investigate the effects of a modified enteral nutrition (EN) formula compared to a standard product on nutrition delivery and feeding intolerance. The experimental EN formula contained MCT oil (80% LCT, 20% MCT), a blend of fibers, and was supplemented with taurine and carnitine. The standard EN formula provided lipid as 100% LCT and contained no fiber, taurine or carnitine. Both formulas were approximately 1 kcal/mL and had similar percentage of calories from carbohydrate, fat and protein.
EN was started at 10-20 mLs/hr and slowly advanced to goal over the next 5 days. Feeding rate was decreased or stopped if gastric residual volume was > 200 mL.
The primary study end points were enteral calorie and protein intakes and the incidence of feeding intolerance. Feeding intolerance was defined as diarrhea (liquid stools ≥5 times in 24 hours or volume ≥200
mL/d), vomiting, increased gastric residuals (≥200 mL), abdominal distention or abdominal exam revealing tympany and/or the absence of bowel sounds. Secondary end points included 28-day ventilator–free days, length of ICU stay, length of hospital stay and in-hospital mortality. Serum levels of D-lactic acid and intestinal fatty acid binding protein were measured at baseline and on study day #5.
Inclusion and Exclusion Criteria:
ICU patients 18–85 years old, APACHE II score ≥12, and an estimated need for EN ≥5 days.
Unstable hemodynamic status, allergy to any EN formula ingredients, contraindication to starting EN (active GI bleeding, paralytic ileus, abdominal compartment syndrome, active inflammatory bowel disease, or severe acute pancreatitis), currently enrolled, or had participated in another clinical study in the past 2 months.
There were 497 patients who required EN screened for study entry, with 144 patients randomized, and ultimately 70 in the intervention feed group and 71 control group patients completed the study. Baseline characteristics were similar between the 2 groups. Most patients (93%) received feeding via a nasogastric tube, with only 7% receiving jejunal feeding, with no significant difference in route of feeding between groups. There was no difference in the use of prokinetic agents between the intervention and control groups. However, significantly more patients in the interventional feed group received opiates (74.6%; 53/71) compared to the control feed group (52.0%; 38/73) during the study (P = 0.002).
The daily enteral calorie and protein intakes from D1 to D5 was significantly greater in the interventional feed group compared to the control feed group (P < 0.01). The percentage of calorie and protein adequacy from D1 to D5 was significantly greater in the interventional feed group compared to the control feed group (P < .01)
The total incidence of feeding intolerance was significantly less in the interventional feed group compared to the control feed group (42.3% interventional feed group and 65.7% in the control feed group, P = .005). Diarrhea occurred in 29.6% (21/71) of patients in the interventional feed group and 38.4% (28/73) in the control feed group.
Increased gastric residuals (as defined by this study) occurred in 4.2% (3/71) of patients in the interventional feed group and 9.6% (7/73) of patients in the control feed group. Vomiting occurred in 2.8% (2/71) of patients in the interventional feed group and 8.2% (6/73) of patients in the control feed group. Abdominal distension occurred in 26.8% (19/71) of patients in the interventional feed group and 43.8% (32/73) of patients in the control feed group. (P-values/statistical significance were not reported for individual feeding intolerance indicators in this article).
The total incidence of feeding intolerance without the subjective measure of abdominal distension (diarrhea, gastric retention, plus vomiting) remained significantly lower in the interventional feed group compared to the control feed group (32.9% in the interventional feed group and 49.3% in the control feed group, P = .047)
There was no significant difference between the study groups in any of the clinical outcomes (28-day ventilator–free days, length of ICU stay, length of hospital stay and in-hospital mortality). There was no significant difference in serum levels of D-lactic acid or intestinal fatty acid binding protein between the study groups.
“…A fat-modified enteral formula with MCTs, carnitine, and taurine may improve feeding tolerance by increasing the daily enteral calorie and protein intake while alleviating feeding intolerance in critically ill patients.”
The authors of this study point out several limitations in the discussion section, including the single blind design, subjective endpoint(s), and a sample size that was only adequate for investigation of feeding intolerance.
Our group quickly noted that the use of a 200 mL cut-off for determination of gastric residual volume was overly conservative, and not applicable to our (or many other hospitals) current practices. We also noted that a diarrhea incidence of > 1/3 of patients in the control group was very unlike what we see in clinical practice. It was especially concerning that no mention was made of any efforts to report on the incidence of clostridium difficile infection, laxation medications, nor to control or report on the use of liquid, elixir or syrup form of medications that may contain sorbitol, and thus contribute to diarrhea. We also noted that significantly more patients in the intervention group received opiates (74%) compared to the control group (52%), which may have affected the incidence of diarrhea.
Although the daily amounts of calories and protein delivered reached statistical difference, the actual amount of difference in nutritional delivery was modest (12 kcals/day more on day 1, up to 156 kcals more/day on day 5; and 2.9 gm protein/day more on day 1, up to 9.1 gm more protein on day 5).
MCT oil may empty more rapidly from the stomach compared with long chain lipids, the differences between the formulas were modest. There is little data that the addition of fiber, carnitine or taurine have beneficial effects on gastric emptying, or acutely improve feeding tolerance in the ICU. Considering that the intervention group received a FODMAP (FOS) that the control group did not, we were surprised that there was any improved tolerance in the interventional group.
Our Take Home Message(s)
- Use of an EN formula that substitutes some LCT with MCT may improve feeding tolerance.
- This study’s lack of recording/reporting medications and infections that might provoke or contribute to diarrhea or distention (sorbitol-containing medications, water-soluble contrast, laxatives, clostridium difficile) limits any conclusions that can be made from this study.
Other News on the UVAHS GI Nutrition Website: (www.ginutrition.virginia.edu):
Latest PG Article: A Clinician’s Guide to Defining, Identifying, and Documenting Malnutrition in Hospitalized Patients
- December 12: Nutrition Support in Pancreatitis by Carol Rees Parrish, MS, RD
- February 8: Nutrition in Acute Kidney Injury by Joe Krenitsky, MS, RD
- March 20: Celiac Disease by Carol Rees Parrish, MS, RD
Joe Krenitsky MS, RDN
PS – Please feel free to forward on to friends and colleagues.