CI: Enteral Nutrition vs. Parenteral Nutrition (2012)

Study Design:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To determine if the institution of enteral nutrition (EN) in pts who are hypermetabolic for 4 to 6 day post sepsis and at risk for multiple organ failure syndrome (MOFS) will reduce incidence of MOFS or post sepsis mortality compared to a parenteral nutrition (PN) control.
Inclusion Criteria:
  • Patient must be an adult; in phase of hypermetabolism 4 to 6 days after sepsis and surgery (must have had surgical intervention and septic event);
  • able to receive either EN or PN.
Exclusion Criteria:
Patients were excluded if
  • with known cirrhosis (clinical or histological criteria);
  • severe malnutrition;
  • known diabetes
  • requiring insulin;
  • receiving steroids,
  • chemotherapy, or radiation.
Description of Study Protocol:

Patient were recruited from the surgical intensive care unit (SICU) at the University of Minnesota. Pts were randomized into the experimental group (EN) and the control group (PN). Commercial formulas given were to achieve 1.5 gm protein/kg/day, 30 nonprotein calories (cal)/kg/day, and salts, minerals, and trace elements to meet protocol the protocol of the university’s nutrition support services.

EN feedings were given through nasoduodenal feeding tubes.

All feedings were administered as 24-hour continuous infusions. No nutritional constraint between injury and 4 to 6 days of hypermetabolism was placed. Assigned nutrition support was continued until a complication (persistent line sepsis or significant intestinal ileus) forced discontinuation, oral feeding was established, extubation, or discharge from SICU. Dropouts occurred when nutrition support had not been given for 24-hour period or discontinued before post injury day 10 to 14.

No changes were made in nutrition support until 18 to 21 days after injury when PN pts were switched to enteral feedings for discharge from the SICU to floor care.

Data Collection Summary:
Nitrogen was analyzed by collecting daily urine and stool specimens for first 8 to 10 days of study. Blood chemistry analysis (transferrin, prealbumin, creatinine, alkaline phosphatase, bulirubin) and expired gas analysis for VO2, VCO2, and respiratory quotient (RQ) before nutrition intervention and on day 8 to 10.
Description of Actual Data Sample:
77 patients enrolled in the study and 66 completed the study (31 EN group and 35 PN group).  Four patients dropped out, 2 from the PN group (recurrent catheter sepsis and excessive VCO2 ventilation) and 2 from the EN group (severe recurrent diarrhea or ileus).
Summary of Results:
  • No difference in incidence of MOFS or mortality between study groups.
  • All mortalities in both groups occurred due to MOFS except 1 PN mortality caused by acute myocardial infarction.
  • Transferrin was higher for PN than EN at day 14 (p <0.05).
  • RQ was significantly higher during PN but didn’t change for EN.
  • 80% of EN and 26% of PN pts experienced at least 1 day of diarrhea.
  • PN caloric intake was closer to 30 nonprotein cal/kg/day goal.
  • PN achieved better nitrogen balance, but not statistically significant.
  • Route of administration had no effect on MOFS/mortality outcome.
  • Retrospective analysis found 2 types of formula given – 100:1 and 170:1 nonprotein calories per gram of protein nitrogen.
  • The 170:1 formula had significant (p<0.05) findings for change in nitrogen balance, change in transferrin, change in preablumin, and RQ.
Author Conclusion:

EN does not appear to reduce the incidence of MOFS or mortality when compared to PN.

This outcome may be due to a possible nutritional effect on mucosal integrity; timing of EN with regard to septic episode; effect of nutritional formulation on mucosal integrity, gut function, or bacterial flora. The study concludes that EN is reasonably equivalent to PN and can be used safely and effectively in presence of sepsis syndrome and MOFS. EN can be provided at lower cost to patient, but is associated with increased incidence of gut complications.

Funding Source:
University/Hospital: University of Minnesota
Reviewer Comments:

Older study.

Patients were subgroup of bigger study. Relatively good exclusion/inclusion criteria with specific definitions. Overall no differences between nutrition outcomes or mortality between groups.
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? N/A
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? N/A
  1.3. Were the target population and setting specified? N/A
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? 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) N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? N/A
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) N/A
  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? 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? 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? 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? N/A
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? N/A
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? N/A
  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? 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? 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? N/A
  9.2. Are biases and study limitations identified and discussed? N/A
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? N/A
  10.2. Was the study free from apparent conflict of interest? N/A