July09.html

University of Virginia Health System

Nutrition Support E-Journal Club

July 2009

 

Greetings,

Summer has been busy with our June traineeship, our July Weekend Warrior program, and Webinars on Parenteral Nutritional and Critical Care.  In addition, some of us have been forced to endure time away from work for family vacations, trips to the beach, or camping expeditions - but we are happy to report we have survived those ordeals and all back to work and our journal club.   

 

July Citation: 

Hsu CW, Sun SF, Lin SL, et al.  Duodenal versus gastric feeding in medical intensive care unit patients: a prospective, randomized, clinical study.  Crit Care Med. 2009 Jun;37(6):1866-72.

Summary: 

This was a randomized study of 121 medical ICU patients comparing nasogastric (NG) versus nasoduodenal (ND) enteral feeding.  The primary outcomes were the daily calorie and protein intake and time to achieve goal nutrition.  Secondary outcomes were "duration of study", duration of ICU and hospital stay, duration of mechanical ventilation, blood glucose level, vomiting, diarrhea, gastrointestinal bleeding, tube replacement, tube clogging, episodes of gastric residual volume > 100 mL, fever, bacteremia, ventilator-associated pneumonia (VAP), and mortality rate.  The bedside caregivers were reportedly blinded to the feeding tube position; however ICU resident physicians evaluated the radiographs and thus were aware of tube location.

Feedings were starting at 20 mL/hr, and advanced by 20 mL/hr every 4 hours until the patient's goal rate was achieved.  Feeding tubes were aspirated for residuals every 4 hours. The frequency of residual checks increased up to every 2 hours if the aspirated volume exceeded 100 mL.  The gastric or duodenal residuals were reinfused if the aspirate volumes were not > 100 mL and discarded if the aspirate volume exceeded 100 mL.  Feedings were stopped for overt aspiration or regurgitation or residual volume > 500mL.  Residual volume of 200-500mL prompted further abdominal and physical exam. 

The authors reported that all of the patients were fed with their head elevated (HOB) to at least 30 degrees to avoid aspiration.  However, there was no reporting of compliance with head-of-bed protocol.  In every study that has looked at this, HOB has never been achieved consistently in the majority of patients.

Inclusion and Exclusion Criteria were:

Inclusion criteria were patients who did not have intractable vomiting, severe diarrhea, or paralytic ileus and were deemed able to receive either NG or ND feeding that was anticipated to last at least 3 days.

Exclusion criteria included abdominal surgery, acute pancreatitis, gastrointestinal bleeding, intestinal obstruction, short bowel syndrome, and chronic renal disease with serum creatinine > 2.5 mg/dL or liver disease with hepatic encephalopathy. 

Major Results reported by authors:

The researchers reported that patients receiving ND feedings received significantly more calories and protein compared to the NG group from the 2nd to 9th day.  The ND group also received a significantly greater percentage of daily calorie goals than the NG group from the 1st to 9th day. 

Patients in the NG group had a significantly increased rate of vomiting (12.9% vs. 1.7%, p = 0.01) and VAP (8.6 vs. 3.1 per 1000 ventilator days, p = 0.01) compared to the ND group.  The study duration, ventilator days, length of stay in ICU, length of hospital stay, and mortality did not differ between the two groups.

Author's Conclusions:

The authors concluded that medical intensive care patients fed via ND tube received more calories and protein, achieved nutritional goals earlier and had less emesis and VAP than patients fed via NG.

Evaluation:

Positive aspects of this study include the fact that it was randomized, and included more patients than a number of previous studies that have examined gastric versus small bowel feeding.  Although the researchers state that group allocation was hidden from the bedside caregivers, it is doubtful that a study of this nature can truly be blinded because caregivers aspirating residuals will certainly suspect which tubes are likely to be gastric from those that reside in the small bowel.  Additionally, the resident physicians were aware of tube location because they confirmed the tube position via radiograph.

One concern in this study is how the tube position was monitored throughout the protocol.  The methods state that, "Tube position was monitored by chest radiograph or residual volume.  If a large residual (>100 mL) was obtained through ND tube, an abdominal radiograph was performed to confirm that gastric migration had not occurred."  However, the methods do not mention that radiographs were routinely monitored in all patients, and thus some gastric tubes could have migrated distal and not have been detected, and those duodenal tubes that migrated proximal with residuals < 100mL would not necessarily have been detected according to the stated methodology.

Another concern the group discussed was the lack of disclosure of how many patients were evaluated and excluded, or those that met inclusion criteria, but did not agree to participate in the study.  Also conspicuous was the absence of any patients that initially met inclusion criteria, but then unable to complete the protocol - something typically encountered in most studies.  These are important concerns in a study of this nature because if only "select" patients are chosen to be randomized, then this limits the "generalizability" of the study i.e.; the results would only apply to a similar subset of patients, and not all medical ICU patients.

Another point of discussion was that the incidence of emesis among the NG fed group (8 out of 62 patients, 12.9 %), the length of time on the ventilator and length of time in the ICU all appear to be substantially greater than what we see in our medical ICU.

From a practical standpoint, it is worthwhile to look at the actual delivery of calories provided between the two groups.  Although the patients receiving small bowel feedings received statistically more formula, the difference in nutrition provided was approximately 230 calories and 10 grams of protein per day.  It is unclear if this difference in nutrition will lead to clinically significant patient outcomes.

Finally, although this study demonstrates that if an ICU team is engaged in small bowel feeding, it can be done in a timely fashion.  Unfortunately, this is more often the exception and not the rule, and several studies have reported that awaiting small bowel placement delayed the initiation of enteral feeding (Neumann, Davies).

This study was larger than previous studies of gastric versus small bowel feeding, however, for an ICU study it was modest size.  This may be reflected in the lack of difference in ventilator days, ICU length of stay or mortality between the two groups despite the significant difference in VAP during the study.

Our Take Home message:

This is the largest single study to date comparing NG vs ND feedings.  Although our group had some concerns, there was no fatal flaw identified to invalidate the study's conclusions.  Although our experience suggests that most medical ICU patients can safely receive gastric feedings, there may be populations that benefit from small bowel placed feeding tubes to reduce VAP and increase adequacy of feeding.

References:

  1. Neumann DA, DeLegge MH. Gastric versus small-bowel tube feeding in the intensive care unit: a prospective comparison of efficacy. Crit Care Med, 2002;30(7):1436-1438.
  2. Davies AR, Froomes PR, French CJ, et al. Randomized comparison of nasojejunal and nasogastric feeding in critically ill patients. Crit Care Med, 2002;30(3):586-590.

Other News:

Weekend Warrior going "on the Road"

  • ยจ Our next Weekend Warrior is going on the road! A 2-day mini-traineeship program is scheduled for Saturday and Sunday, October 3-4, 2009 in Chicago at Northwestern University Medical Center. If you know anyone who might not be able to get away for our full week traineeship, please let them know about our weekend program, and to check out our website for full information (below).

Check out the full schedule of webinar programs at:

 http://www.healthsystem.virginia.edudh/webinars.html

  • September 22: Managing the Adult Patient with Short Bowel Syndrome: A Clinical Approach--Carol Parrish, MS, RD
  • October 27: Pediatric Parenteral Nutrition--Ana Abad-Jorge, MS, RD, CNSC
  • November 17: Nutrition Support in Renal Failure--Joe Krenitsky, MS, RD
  • December 8: Enteral Nutrition--Carol Parrish, MS, RD

See the latest Practical Gastroenterology articles:

  • Thomson AD, Guerrini I E, Marshall EJ. Wernicke's Encephalopathy: Role of Thiamine.  Practical Gastroenterology 2009;XXXIII(6):21.
  • Dixon M. When What Comes Out Is Way More Than What Goes In: Perineal Skin Care. Practical Gastroenterology 2009;XXXIII(7):29.

Available at: http://www.healthsystem.virginia.edu/pub/digestive-health/nutrition/resources.html

Joe Krenitsky MS, RD

Carol Rees Parrish MS, RD

PS - Please feel free to forward this on to friends and colleagues.