CI: Initiation of Enteral Nutrition (2012)


Heyland DK, Dhaliwal R, Drover JW, et al. Canadian clinical practice guidelines for nutrition support in mechanically ventilated, critically ill adult patients. JPEN. 2003; 27: 355-373.

PubMed ID: 12971736
Study Design:
Meta-analysis or Systematic Review
M - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
To develop evidence-based clinical practice guidelines for nutrition support in mechanically-ventilated critically-ill patients.
Inclusion Criteria:
PRCT or evidence analysis reports concerning any of the following topics:
  • Enteral vs. parenteral
  • Early vs. late enteral
  • Composition of enteral formula
  • Strategies to optimize enteral delivery and minimize risks
  • Rate of advancement
  • Checking residuals
  • Bedside algorithms
  • Motility agents
  • Small bowel vs. gastric feedings
  • Semi-recumbent positioning
  • Closed delivery systems
  • Probiotics
  • Bolus administration
  • Enteral plus supplemental parenteral nutrition
  • Composition of parenteral nutrition
  • Intensive insulin therapy.
Exclusion Criteria:


Description of Study Protocol:
  • Search Medline, CINAHL, EMBASE and Cochrane Library for RCT and meta-analyses of RCT of nutrition support in critically-ill adults
  • Search reference lists and personal files
  • Systematically appraise each study in duplicate using standard scoring system
  • Clinical trials score level-one if randomization concealed, outcome adjudication blinded and intent-to-treat analysis performed
  • Trials assigned level-two if any one of the above characteristics unfulfilled
  • For reports from similar studies, we combined data to estimate the common risk ratio and associated 95% CI for death and infectious complications
  • Panel discussion of findings
  • External review of clinical practice guidelines developed.
Data Collection Summary:
  • Mortality
  • ICU and hospital LOS
  • Quality of life
  • Specific complications.
Description of Actual Data Sample:
Summary of Results:
  • Enteral vs. parenteral: Compared 12 level-two and one level-one PRCT with
    • No difference in mortality (RR=1.08; 0.7 to 1.65)
    • Decrease in infectious complications (RR=0.61; 0.44 to 0.84).
  • Early vs. late enteral nutrition: Compared eight level-two PRCT
    • Trend towards reduced mortality with early (RR=0.52; 0.25 to 1.08)
    • Trend towards reduced infectious complications (RR=0.66; 0.36 to 1.22; P=0.19)
    • No difference in LOS
    • Improved caloric, protein, percentage.
  • Gastric vs. SB feeding: Reviewed 11 PRCT studies
    • Mortality: NS difference between groups (RR=0.98; 95% CI, 0.72 to 1.20; P=0.6)
    • Significant reduction in infections with SB vs. gastric feedings (RR=0.77; 95% CI, 0.60 to 1.00; P=0.05)
    • Pneumonia: In nine studies, incidence of VAP was 83/288 for gastric vs. 6/255 for SB feedings (OR=0.77; 95% CI, 0.6 to 1.00; P=0.05). There was a modest effect size with wide CIs among heterogenous studies and investigators discussed concerns about implementation of SB feeding and associated costs.
  • Achieving target dose of enteral formula: Evaluated one level-two study of patients with severe head injury and recommended optimized delivery strategies (start at goal, tolerate 250ml GRV, small bowel feedings)
  • Arginine-based diets
    • Evaluated two level-one and 12 level-two studies and found no difference in mortality, even when the sub-group was analyzed for high- vs. lower-quality studies and trauma vs. non-trauma patients
    • No difference in infectious complications
    • Associated with a reduction in hospital LOS (-0.45 days; 95% CI, -0.9 to 0.00; P=0.05), trend toward a reduction of ICU LOS and vent days. Latter findings with statistical heterogeneity.
  • Fish oils, borage oils, antioxidants in ARDS
    • One level-one study had fewer ICU LOS (11 vs. 14.8; P=-0.016)
    • Decrease in new organ failures (10% vs. 25%; P=0.018).
  • Glutamine-supplemented enteral nutrition
    • Four level-two and one level-one study showed a modest treatment effect with wide Cis and heterogeneity across trials
    • Largest effect in one unpublished trial.
  • Peptide-based product vs. whole protein: Four level-two studies compared peptide-based to intact protein with no difference in mortality or infectious complications
  • Enteral feeding protocol use
    • Insufficient data from randomized trials to make recommendation
    • If protocol is used, 250ml GRV and prokinetics should be considered.
  • Routine use of motility agents: Given low probability of harm, favorable feasibility and cost, motility agents may be considered as strategy to optimize nutrient intake
  • Small bowel vs. gastric feeding: According to 11 level-two studies, small bowel feeding may be associated with reduction in pneumonia
  • Semi-recumbent positioning: According to one level-two study, head of the bed elevation to 45 degrees is recommended where possible
  • Parenteral nutrition vs. standard care: Parenteral nutrition may be associated with increase in complications and LOS
  • Glutamine-based parenteral nutrition: According to two level-one and three level-two studies, when parenteral nutrition is prescribed, supplementation with glutamine (where available) is recommended
  • Hypocaloric PN: Two small level-two trials of patients not malnourished and tolerating some enteral nutrition determined hypocaloric parenteral nutrition should be considered
  • Use of lipids
    • Decrease in infectious complications in patients with no lipids (RR=0.64, 0.42-0.93)
    • According to two level-two studies, in not malnourhsed patients tolerating some enteral nutrition or parenteral nutrition for less than 10 days, withholding lipid should be considered.
  • Tight glucose control: According to one level-two study, in surgical critically-ill patients, intensive insulin therapy to keep glucose between 4.4mmol and 6.1mmol per L should be considered due to reduced sepsis (P=0.003), reduced ICU and hospital mortality (P=0.01).
Author Conclusion:
  • Strongly recommend enteral over parenteral nutrition
  • Recommend use of a standard polymeric enteral formula
  • Initiate formula within 24 to 48 hours after ICU admission
  • Care for patients in a semi-recumbent position
  • Do not use arginine-containing enteral products
  • Consider strategies to optimize enteral delivery
    • Start at target rate
    • Use feeding protocol with a higher threshold of gastric residual volume
    • Use motility agents
    • Use small bowel feeding.
  • Consider use of products with fish oil, borage oil and antioxidants for patients with ARDS
  • Consider a glutamine-enriched formula for patients with severe burns and trauma
  • Minimize parenteral nutrition risk by considering
    • Hypocaloric dose
    • Withhold lipids
    • Intensive insulin therapy.
  • Insufficient data to generate recommendations regarding:
    • Use of indirect calorimetry
    • Optimal pH of enteral formula
    • Supplementation with trace elements, antioxidants or fiber
    • Optimal mix of fats and carbohydrates
    • Use of closed feeding system
    • Continuous vs. bolus feedings
    • Use of probiotics
    • Type of lipids
    • Mode.
Funding Source:
University/Hospital: Queens University, University of Alberta, St. Paul's Hospital
Reviewer Comments:
  • There is a concern that aggregated results from small trials may not be adequately powered to answer mortality outcome questions
  • Consideration of feasibility and cost were also included in development of these practice guidelines
  • Multi-disciplinary committee members.
Quality Criteria Checklist: Review Articles
Relevance Questions
  1. Will the answer if true, have a direct bearing on the health of patients? Yes
  2. Is the outcome or topic something that patients/clients/population groups would care about? Yes
  3. Is the problem addressed in the review one that is relevant to dietetics practice? Yes
  4. Will the information, if true, require a change in practice? Yes
Validity Questions
  1. Was the question for the review clearly focused and appropriate? Yes
  2. Was the search strategy used to locate relevant studies comprehensive? Were the databases searched and the search termsused described? Yes
  3. Were explicit methods used to select studies to include in the review? Were inclusion/exclusion criteria specified andappropriate? Wereselectionmethods unbiased? Yes
  4. Was there an appraisal of the quality and validity of studies included in the review? Were appraisal methodsspecified,appropriate, andreproducible? Yes
  5. Were specific treatments/interventions/exposures described? Were treatments similar enough to be combined? Yes
  6. Was the outcome of interest clearly indicated? Were other potential harms and benefits considered? Yes
  7. Were processes for data abstraction, synthesis, and analysis described? Were they applied consistently acrossstudies and groups? Was thereappropriate use of qualitative and/or quantitative synthesis? Was variation in findings among studies analyzed? Were heterogeneity issued considered? If data from studies were aggregated for meta-analysis, was the procedure described? Yes
  8. Are the results clearly presented in narrative and/or quantitative terms? If summary statistics are used, are levels ofsignificance and/or confidence intervals included? Yes
  9. Are conclusions supported by results with biases and limitations taken into consideration? Are limitations ofthe review identified anddiscussed? Yes
  10. Was bias due to the review's funding or sponsorship unlikely? Yes