CI: Enteral Nutrition Energy Delivery (2012)


Dickerson RN, Boschert KJ, Kudsk KA, Brown RO. Hypocaloric enteral tube feeding in critically ill obese patients. Nutrition. 2002; 18: 241-246.

PubMed ID: 11882397
Study Design:
Retrospective Cohort Study
B - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

To compare, retrospectively, the nutritional and clinical efficacies of eucaloric and hypocaloric enteral feedings in critically ill, obese patients in the trauma or surgical intensive care unit (ICU).

Inclusion Criteria:
  • Admission to trauma or surgical ICU
  • Adults aged 18 to 69 years
  • Pre-resuscitation weight greater than 125% of ideal body weight
  • Required enteral tube feeding at least seven days.
Exclusion Criteria:
  • Immune-enhancing diet
  • Hepatic dysfunction
  • HIV
  • Malabsorption
  • Renal dysfunction
  • Cancer
  • Pregnancy.
Description of Study Protocol:


Referred to nutrition support team and met inclusion criteria.


Retrospective cohort (chart review of 40 multiple trauma patients receiving PN over three years, grouped by energy level).


  • Patients stratified by energy level:
    • N=12 eucaloric (more than 20kcal per kg, adjusted body weight per day)
    • Hypocaloric (less than 20kcal per kg per day) feeding with 2g per kg of IBW of protein
  • Nutrition support team assigned feeding (eucaloric or hypocaloric).

Statistical Analysis 

  • T-test for independent variables to compare single measurements between two groups
  • Pairwise comparisons by Mann-Whitney U test for non-parametric analysis
  • Fisher's exact test or Chi-square test of homogeneity for all nominal data
  • Repeated measures ANOVA to detect differences in measures between two populations
  • Significance set a priori at P≤0.05.
Data Collection Summary:

Timing and Method of Measurements  

  • Blood samples for serum prealbumin and albumin levels drawn after initiation of nutrition support on mean days two, nine, 17 and 23 of feeding
  • Daily serum blood glucosed averaged weekly
  • Nitrogen balance mean days six and 14.

Dependent Variables (Outcomes) 

  • LOS
  • ICU stay
  • Days of mechanical ventilation
  • Antibiotic therapy
  • Infectious events.

Independent Variables

Hypocaloric feeding with 20kcal per kg or more or eucaloric feeding.

Description of Actual Data Sample:

40 patients met the entry criteria between 1996 and 2000:

  • 12  eucaloric feedings
  • 28  hypocaloric feedings.
Summary of Results:

Key Findings

  • Hypocaloric group had shorter ICU LOS:18.6 vs. 28.5 days (P<0.03)
  • Hypocaloric group had fewer antibiotic days: 16.6 vs. 27.4 days (P<0.03)
  • Days of mechanical ventilation approached a reduction with hypocaloric feedings: 15.9 vs. 23.7 days (P=0.09)
  • NS difference in nitrogen balance or serum protein responses: (P>0.05).


Author Conclusion:

These data suggest that hypocaloric EN support is at least as effective as eucaloric feeding in critically ill, obese patients.

Funding Source:
University/Hospital: Unviersity of Tennessee Health Science Center, Regional Medical Center
Reviewer Comments:
  • Eucaloric group mean BMI was 36kg per m2 vs. 41.3kg per mfor hypocaloric (perhaps NS difference due to small sample)
  • Mean intake on week one was 74% in eucaloric vs. 53% of 25kcal per kg week in hypocaloric.
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.) No
  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? N/A
  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? Yes
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? Yes
  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? Yes
  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? 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? Yes
  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? Yes
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? 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)? N/A
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? No
  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