CI: Enteral Nutrition vs. Parenteral Nutrition (2012)

Study Design:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To investigate the effect of early nutrition by comparing two methods of administration; TPN versus enteral feeding.
Inclusion Criteria:
  1. Patients suffering from isolated head injuries.
  2. Glasgow Coma Scale of 10 or less at 6 hours post-injury.
  3. Trauma patient between July  1984 and May 1985.
  4. Absence of any of the conditions stated in the exclusion criteria.
  5. Informed consent was obtained from patient’s families.
Exclusion Criteria:
Any patient not meeting the requirements listed in the inclusion criteria
Description of Study Protocol:
Patients were randomly assigned into either the early TPN or the early enteral group based on their day of admittance. 
REE was determined by indirect calorimetry for the first 20 patients.  The Harris Benedict equation was also used to determine calorie requirements for all 45 patients.
Nutritional support was begun within 48 hours of admittance for both the TPN and the EN groups.
Enteral Nutrition was Isocal HCN, and the TPN mixture was a standard 8.5% amino acid, 25% glucose solution with electrolytes, vitamins, and trace elements. 10% Intralipid was given twice a week. 
Patients were studied for 14 days or until urinary nitrogen was below 14 gm/day.
Data Collection Summary:

GCS score, infections/feeding complications, urinary Nitrogen excretion, albumin, nitrogen balance.

  1. Infection
  2. Death
  3. Nitrogen balance
  4. Albumin
  5. Weight
  6. Effect of steroids
  7. Caloric balance
Description of Actual Data Sample:
45 total patients were studied
  •     40 males, 5 females
  • Median age:  27 y/o males and 34 y/o for females
    •      21 randomized to the enteral group
    •      24 randomized to the TPN group
Summary of Results:
  • Twenty five of the forty-five patients developed some kind of infection. 9 out of the TPN  and 10 out of  The enteral group developed pneumonia. Other infections that occurred were sepsis, wound infection, meningitis and urinary tract. No significant difference existed between the two groups.
  • Five patients total died during this study.  3 in the enteral  group and 2 in the TPN group.
  • Four of these patients died of malignant hypertension, reemphasizing the need to use caution when using Large fluid volumes with head injured patients.
Nitrogen Balance
  • Only 5 patients total achieved positive nitrogen balance.  (4 in the enteral and 1 in the TPN group).
  • Serum albumin levels dropped for both groups by approximately 13%.
Effect of Steroids:
  • 16 patients were treated with steroids during this study.  these patients experienced the same mean daily nitrogen loss as the other group, no significant difference was found regarding nitrogen balance.
  • Patients in the TPN lost 4.9kg
  • Patients in the enteral group lost 5.1 kg on average. there was not a significant difference between the groups.
Calorie Balance:
  • Positive calorie balance was reached by all patients participating in the study. Positive balance occurred at  day 12 for the enteral group and Day 9 for the TPN group.
Author Conclusion:

During this study no significant differences were found between the TPN and the enteral group.

The data collected indicates that early nutrition helps sustain lean muscle and energy stores.

The authors favor enteral feedings as the primary choice for head injured patients.  Enteral feedings provide adequate nutrition at a lower cost and at a fairly small complication rate.

Funding Source:
University/Hospital: St Joseph's Hospital and Medical center
Reviewer Comments:
Researchers did not provide detailed allocation concealment.
Researchers used indirect calorimetry on the first 20 patients, and did not indicate why it was not used on the entire series.
Small sample size,  8:1 male to female ratio (40 subject  male,5 subjects female).
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? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? ???
  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? ???
  2.2. Were criteria applied equally to all study groups? No
  2.3. Were health, demographics, and other characteristics of subjects described? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? ???
3. Were study groups comparable? N/A
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) No
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? Yes
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) Yes
  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? ???
  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%.) Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? Yes
  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? No
  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.) No
  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? ???
  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? Yes
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? Yes
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? N/A
  6.6. Were extra or unplanned treatments described? ???
  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? Yes
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  7.2. Were nutrition measures appropriate to question and outcomes of concern? Yes
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? Yes
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? Yes
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? ???
  7.7. Were the measurements conducted consistently across groups? No
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? ???
  8.1. Were statistical analyses adequately described and the results reported appropriately? ???
  8.2. Were correct statistical tests used and assumptions of test not violated? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  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)? No
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? ???
  8.6. Was clinical significance as well as statistical significance reported? Yes
  8.7. If negative findings, was a power calculation reported to address type 2 error? No
9. Are conclusions supported by results with biases and limitations taken into consideration? N/A
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? No
  10.2. Was the study free from apparent conflict of interest? Yes