CI: Enteral Nutrition vs. Parenteral Nutrition (2012)

Study Design:
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Quality Rating:
Research Purpose:
To compare the impact of immediate Total Enteral Nutrition (TEN) versus Total Parenteral Nutrition (TPN) after major abdominal injury.
Inclusion Criteria:
Abdominal trauma index (ATI) 15-40, nutrition support started w/in 12 hours of surgery,
Exclusion Criteria:
Pelvic fractures needing >6 units of blood wtihin first 12 hours, > 25 units of blood loss in first 24 hours, repeat laparotomy of death within 72 hours
Description of Study Protocol:

All adult patients (pt) admitted to Denver General Hospital in 28 month time period, with ATI 15-40 were randomized into the TEN group or TPN group. Groups were comparable with respect to age, gender, injury, injury severity, physiologic status. 

  • TEN (patients) received low-residue, high nitrogen diet: 33% branched-chain amino acid (BCAA), 2.5% calories (cal) from fat, 82% cal simple carbohydrates and macro/micronutrients according to needs. 
  • TPN patients received 1kcal/ml, 33% BCAA, 2.2% fat, 84% carbohydrate, and macro/micronutrients according to needs. 

Basal energy expenditure (BEE) calculated using Harris-Benedict and multiplied by a factor of 1.5, and results were confirmed by indirect calorimetry.  Nitrogen balance was determined on day 1, 5, and 10.  Nutrition support was continued at rate that met caloric and nitrogen needs until oral intake was adequate.

Trauma status was evaluated using Revised Trauma Score (RTS) for physiologic status by combining Glasgow Coma Scale, systolic blood pressure, and respiratory rate; ATI for intra-abdominal injury; Injury Severity Score (ISS) of Baker assessed multisystem trauma; survival probability estimated by TRISS Score of the ACS Committee on Trauma.  All septic infections were categorized as major (intra-abdominal abscess or pneumonia) or minor (wound, urinary tract, catheter, or other peripheral sites).

Data Collection Summary:

Labs measured were Urine Urea Nitrogen (UUN). Nitrogen balance was determined on day 1, 5, and 10 by calculating nitrogen loss for 24-hour period using daily UUN excretion plus estimated stool and obligatory nitrogen loss of 4 g.

Venous blood samples drawn w/in 12 hours of laparotomy (baseline), day 5, and day 10 were analyzed for complete blood count w/ differential, transferring, retinol binding protein, bilirubin, alkaline phosphatase, amino acid profile, and insulin level.

Description of Actual Data Sample:

75 subjects (39 TEN, 36 TPN), 16 were excluded due to: early death (4), reoperation w/in 72 hours (3), chronic disease (3), ATI >40 (2), head injury w/fluid restriction (2), failure of TEN (1), early transfer (1).

Final group included 59 subjects (29 TEN, 30 TPN).  

Summary of Results:
  • 4 TEN pts failed to tolerate feeding protocol increments
  • Day 5 caloric and nitrogen intakes were higher for TPN than TEN, but no significant difference between nitrogen balance.
  • At day 10 TEN pts had significantly higher albumin 3.4 ± 0.1 vs TPN 2.7 ± 0.2 (p = 0.01) and transferrin 216 ± 10 vs TPN 150 ± 18 (p = 0.05).
  • TPN pts had higher levels of bilirubin, alkaline phosphatase, and glucose, but were not significant.
  • 10 (34%) of TEN patientshad complications vs 17 (57%) of TPN patients
  • Nonseptic complications include pancreatitis, atelecctasis, recurrent pneumothorax, partial small bowel obstruction, biliary fistula, breakdown of exteriorized colon repair, and CSF leak.
  • Septic complications: intra-abdominal abscess, pneumonia, wound, urinary tract, catheter, other peripheral sites
  • Overall Septic morbidity was 5 patients (17%) of TEN group vs 11 patients (37%) of TPN group.
  • 1 pt (3%) on TEN vs 6 (20%) on TPN developed major infections.
  • TPN was significantly correlated with pneumonia (p = 0.02) and identified as an independent variable for pneumonia by multiple logistic regression model analysis.
Author Conclusion:
TEN showed a significant advantage in reducing major septic complications, esp. pneumonia, when compared to TPN. Acutely injured patients w/ midline lapartomy are at moderate risk to develop nosocomial pneumonia.  Proposes gut bacterial translocation as a mechanism to increased infections when enteral nutrition is delayed.
Funding Source:
University/Hospital: Denver General Hospital, University of Colorado Health Sciences Center
Reviewer Comments:
This study in the late 1980s showed that enteral nutrition may be tolerated in severely injured patients and resulted in less infection complications.  Noted that the overall septic morbidity was not significantly different, but major infections were significantly reduced..
Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) Yes
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? N/A
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? N/A
  1.3. Were the target population and setting specified? N/A
2. Was the selection of study subjects/patients free from bias? Yes
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? N/A
  2.2. Were criteria applied equally to all study groups? N/A
  2.3. Were health, demographics, and other characteristics of subjects described? N/A
  2.4. Were the subjects/patients a representative sample of the relevant population? N/A
3. Were study groups comparable? Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? N/A
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) N/A
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? N/A
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) N/A
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
4. Was method of handling withdrawals described? Yes
  4.1. Were follow-up methods described and the same for all groups? N/A
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) N/A
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? N/A
  4.4. Were reasons for withdrawals similar across groups? N/A
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
5. Was blinding used to prevent introduction of bias? No
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? N/A
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) N/A
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? N/A
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? N/A
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? N/A
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? N/A
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? N/A
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? N/A
  6.6. Were extra or unplanned treatments described? N/A
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? N/A
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? No
  7.1. Were primary and secondary endpoints described and relevant to the question? N/A
  7.2. Were nutrition measures appropriate to question and outcomes of concern? N/A
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? N/A
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? N/A
  7.5. Was the measurement of effect at an appropriate level of precision? N/A
  7.6. Were other factors accounted for (measured) that could affect outcomes? N/A
  7.7. Were the measurements conducted consistently across groups? N/A
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? No
  8.1. Were statistical analyses adequately described and the results reported appropriately? N/A
  8.2. Were correct statistical tests used and assumptions of test not violated? N/A
  8.3. Were statistics reported with levels of significance and/or confidence intervals? N/A
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? N/A
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? N/A
  8.6. Was clinical significance as well as statistical significance reported? N/A
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? N/A
  9.2. Are biases and study limitations identified and discussed? N/A
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? N/A
  10.2. Was the study free from apparent conflict of interest? N/A