CI: Initiation of Enteral Nutrition (2012)

Study Design:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:

To assess whether early enteral feeding (less than 24 hours) vs. late (more than 72 hours) attenuates the stress response and improves patient outcomes after blunt trauma.


Inclusion Criteria:
  • Patients in ICU after blunt trauma
  • Older than 17 years of age
  • Injury Severity Score higher than 13
  • Feeding support anticipated for seven days
  • Ability to start enteral feeding via a tube place distal to the pylorus within 24 hours after admission to the ICU.
Exclusion Criteria:
  • Contraindication to enteral feeding
  • Contraindication to placement of an enteral tube within 24 hours after ICU admission
  • Admission creatinine higher than 2mg per dL
  • Admission bilirubin higher than 3mg per dL
  • Pre-existing malnutrition according to history or physical examination
  • Use of steroids, radiation or chemotherapy
  • Malignancy                     
  • Acute spinal cord injury.
Description of Study Protocol:
  • Eligible patients randomized to one of two groups [early enteral feeding (less than 24 hours after ICU admission) or late enteral feeding (more than 72 hours after ICU admission)] by a card drawn from a sealed envelope
  • The study was completed after the tenth study day, the day when oral intake could be resumed or on the day a patient went 24 hours without receiving any nutrients
  • Both groups received a peptide-based formula, Riabilan HN. Full-strength formula was started at 25ml per hour and advanced by 25ml per hour every four hours until target rate was reached. Target rate was to provide 1.5g protein per kg per day unless fluid restriction was necessary. Patients in both groups received 83% of the goal feeding for the entire study. Enteral administration rates were adjusted once per week to achieve nitrogen equilibrium, which was based on 24-hour urinary urea nitrogen.
  • 24-hour urine collections were obtained daily. Total urinary nitrogen, cortisol, epinephrine, norepinephrine, dopamine and creatinine levels were determined on batched samples for day zero, five and 10.
Data Collection Summary:
  • The primary outcome variable was the degree of metabolic response, as evaluated by:
    • Urinary catecholamines (epinephrine, norepinephrine and dopamine)
    • Total urinary nitrogen
    • Cortisol excretion
  • Secondary outcome variables were:
    • Infections
    • ICU days
    • Ventilation days
    • Mortality.
Description of Actual Data Sample:
  • Intensive Care patients with blunt trauma were randomized to either the early or late enteral feeding regimen
  • The beginning sample size was 52, but 14 patients were dropped from the analysis due to medications, tube complications or other complications
  • The final sample size was 38, with 19 patients in each group.
Summary of Results:
  • The time from trauma ICU admission to feeding was significantly different between groups  (early, 31±13 hours;  late, 82±11 hours; P<0.001)
  • Mean PaO²/FiO² ratios were similar between groups (early, 201±114; late, 248±100); the early feeding group had more severe acute lung injuries (PaO²/FiO² less than 150); P<0.05
  • There were no significant differences in primary outcome variables (total urinary nitrogen, nitrogen balance, epinephrine, norepinephrine, dopamine and cortisol)
  • There were no significant differences in secondary outcome variables (days in ICU, ventilator days, organ system failure, individual infections and mortality)
  • Total infections (pneumonia, UTIs, abdominal abscess, wound infections, catheter sepsis, bacteremia, sinusitis and an eye infection) were higher for the early EN group (P<0.05). Data were analyzed by patient to ensure no bias from a few patients having all the infections.
Author Conclusion:
  • The metabolic response, ICU length of stay, ventilator days and mortality were not decreased by early enteral feeding in severely injured blunt trauma patients
  • Total infectious complications were increased in the early feeding group
  • No significant differences in patient outcome between the two groups
  • Ten-day study period may have been too short of an interval for analysis.
Funding Source:
Pharmaceutical/Dietary Supplement Company:
University/Hospital: University of Minnesota, St Paul-Ramsey Medical center, Methodist Hospital,
Reviewer Comments:
  • Sample size small
  • Not blinded
  • More acute lung injury in the early fed group (not equal at baseline)
  • Early feeding within 24 hours, delayed feeding greater than 72 hours. However, patients had initiated of enteral feeding on average at 39 hours post-injury.
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? 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? 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? ???
  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.) Yes
  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? Yes
  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? N/A
  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? 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? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? Yes
  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)? Yes
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? Yes
  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? Yes
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