CI: Enteral Nutrition vs. Parenteral Nutrition (2012)

Citation:
Young B, Ott L, Twyman D, Norton J, Rapp R, Tibbs P, Haack D, Brivins B, Dempsey R. The effect of nutritional support on outcome from severe head injury.  Journal of Neurosurgery 1987; 67:668-76.
 
Study Design:
Randomized Controlled Trial
Class:
A - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
To determine how neurological outcome is affected by nutrition support.
Inclusion Criteria:
  1. Glasgow Coma Scale (GCS) score between 4 and 10 during the first 24 hours after admission.
  2. Brain as the primary site of injury.
  3. Informed consent.
Exclusion Criteria:
  1. Patients who were brain dead  within 4 days of the initiation ofthe study.
  2. Patients whose family decidedto remove them from the study within 5 days after they were enrolled.
  3. Lack of the above inclusion criteria.
Description of Study Protocol:

58 consecutive eligible subjects were randomly assigned to either receive total parenteral nutrition (TPN) or enteral nutrition (EN).  Subjects stayed in these groups throughout the course of the study in terms of statistical analysis.

Upon admission, subjects were studied for 18 days. 

Salem pumps were inserted nasogastrically. 

Basal energy expenditure (BEE) was determined by the Harris-Benedict equation.  Strong effort was made to achieve a caloric intake of 1.75 (activity factor) x BEE and 1.5 gm protein/kg body weight/day.

In the TPN group, nutrition support was started within 48 hours after injury.  The formula consisted of sterile amino acid/dextrose solutions, multivitamins, trace elements, and intravenous lipid emulsions.  Enteral feedings were initiated in this group when bowel sounds were present, and residuals were less than 100 cc/2 hours (if fed into the stomach).

In the EN group, when low wall suction was not required either a Duotube or Keofeed feeding tube was inserted and feeding was started.  Subjects received continuous feeding of Traumacal or Ensure Plus formula.

Subjects in the EN group were given TPN on day 7 if they had been unable to tolerate EN feeding.

At 3 months, 6 months, and 1 year after injury, outcome of subjects was assessed by the GCS.  The neurosurgeon who measured outcome by the GCS scores was blinded as to the patient’s nutrition group.  It was considered a favorable outcome if a good recovery or moderate disability was seen.  It was considered an  unfavorable outcome if severe disability, state of vegetation, or severe disability was seen.

Data Collection Summary:

GCS scores, caloric intake, albumin, retinol-binding protein (RBP), triceps skin fold (TSF), mid-arm circumference, infection.

Outcome(s) and Other measures:

  1. Death
  2. Time to tolerance
  3. Neurological outcome- GCS
  4. Infection
     

Description of Actual Data Sample:

1 total head-injured patients were involved in the study.

  • 28 in the EN group (6 females, 22 males, mean age of 34.0 years ± 2.92).
  • 23 in the TPN group (3 females, 20 males, mean age of 30.3 years ± 2.67).
Summary of Results:

Death:

Early vs. late deaths (<18 days vs. >18 days after injury), was not statistically different between the two groups (p= 0.36 and p= 0.71, respectively).

Time to tolerance:

The EN group was not able to match the caloric intake of the TPN group until about the 9th day of the study.

Eleven of those in the EN group (35.5%) were not able to tolerate EN by day 7 postinjury and were started on parenteral support.

Neurological Outcome:

  • The peak 24-hour GCS score was not significantly different upon admit between the two groups, however, over the 18 days of the study, the TPN and EN group did show significant difference.
  • The TPN group showed an average 4-point increase.       
  • The EN group showed an average 3-point increase.
  • Those in the TPN group had more subjects with favorable outcomes at 3 months than the EN group (43.5% vs. 17.9%, respectively) (p= 0.05)..
  • At 6 months, the percentage of TPN subjects with favorable outcomes remained the same at 43.5%, but subjects in the EN group  with favorable outcomes raised to 32.1% (p= 0.29).

After 1 year, 47.8% of the TPN group and 32.1% of the EN group showed favorable outcomes (p= 0.20).

Infection:

Infections were reported in 17.4% of the TPN group, and 17.9% in the EN group.

Septic shock was seen only in the EN group, with an incidence of 10.7% (p= 0.16).  The population of those who experienced septic shock came from those who had not tolerated EN feedings by day 7 and were started on TPN.

Author Conclusion:

Patients receiving better nutrition support fair better in neurological recovery during the first 3 months.

  • TPN patients received significantly more calories and protein and had significantly better outcomes than EN patients.
  • Those who were less susceptible to sepsis had better outcome.

Patients who were in the EN group and started TPN on day 7 because they were unable to tolerate EN had a statistically higher incidence of septic shock, possibly due to immunocompetence caused by the lack of proper nutrition support.

Patients with better early nutritional support experience better neurological recovery.

Funding Source:
University/Hospital: University of Kentucky Medical Center, Henry Ford Hospital,
Other: Statistical Consultants Inc
Reviewer Comments:

No difference in outcome was seen between those receiving

Traumacal or Ensure Plus.

No mention of method of randomization.

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? No
  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) ???
  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? 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%.) Yes
  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? 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? 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? Yes
  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? 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