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 route of nutritional support. To determine total complications rate of both nutritional routes. And to identify the cost versus charge performance of nutritional support.
Inclusion Criteria:
Adults 18 – 60 year old with head injuries with a Glasgow Coma Scale of 8 or less and a persistent coma.
Exclusion Criteria:
Spinal cord injuries, metabolic disorders, renal failure, IBD, status 72-hours post injury, or prognosis of rapidly fatal injury.
Description of Study Protocol:
Randomization and initiation of nutrition support within 72 hours of injury.  Start up formulations, rates of advancement, and monitoring were standardized for all participants.    Target rates of calorie support were based on Harris-benedict equations plus 50%.  One group was given jejunal tube feedings, the other group received TPN and on the 5th day attempts to convert to gastric feedings. UUN results guided protein replacement. Indirect calorimetry was conducted every 3 days. 5 weeks.
Data Collection Summary:

Laboratory values collected were:

  • Urine urea nitrogen,
  • blood glucose,
  • blood chemistries,
  • transferrin,
  • albumin,

Complications were infectious or nutrition-related. Caloric needs based on indirect calorimetry after stabilization.

Complications included infection, intolerance of feeding, tube dysfunction, pneumonia, hyperglycemia, and diarrhea.

Efficiency of feeding was measured by the ratio of calories delivered to 120% of measure resting energy expenditure
Description of Actual Data Sample:

21 received TPN, and 28 patients received Enteral nutrition

Homogeneity was established between the two groups.

Summary of Results:
  • No significant difference between TPN/ENT for N2 excretion, intake, or balance.
  • No significant difference between TPN vs. Enteral nutrition for measured resting energy expenditures.
  • RQ for entire group = 0.91 ± 0.08.
  • Post hoc analysis comparing isolated head injury to closed head injury with associated injuries found measured resting energy expenditure and nitrogen excretion over time are not significantly different.  Only in week 1 did TPN patients have a significant elevated nitrogen excretion. p<0.05.
  • No significant differences between Transferrin or Albumin levels between two groups.
  • Hyperglycemia more common among TPN pts. p < 0.05
  • Significantly greater number of patients with diarrhea in TPN group. (p < 0.05) Significantly greater patient days with diarrhea in TPN group.
  • No significant difference in aspiration between groups.
  • No significant differences in occurrence rates of infections.
  • Subset of 10 TPN and 10 EN had entire hospital bill analyzed. Average total nutrition costs were $2,020 and $1,202 respectively. Total daily charges were $11,375 and $4,015 respectively.   Samples had similar length of stays, injury severity scores, associated injuries, and relative outcomes. 
  • Charges were higher for TPN than ENT.
Author Conclusion:
Hypermetabolism persists for 4-6 weeks even after awakening from coma. Nutrition support should be based on measured resting energy expenditure and UUN. Authors recommend feeding 120% of MREE and 2.5 g/kg/d of protein.  They did not find a reduction in infectious morbidity in early enteral feedings. They found jejunal feeds result in less hyperglycemia, less diarrhea and less patient charge.
Funding Source:
University/Hospital: Legacy Emanual Hospital
Reviewer Comments:
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? 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? Yes
  2.2. Were criteria applied equally to all study groups? Yes
  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? Yes
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) Yes
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? ???
  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? Yes
  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? Yes
  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%.) ???
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? No
  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? N/A
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? Yes
  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? Yes
  6.6. Were extra or unplanned treatments described? Yes
  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? Yes
  7.7. Were the measurements conducted consistently across groups? Yes
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? ???
  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? Yes
  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? Yes
  10.2. Was the study free from apparent conflict of interest? Yes