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CI: Gastric vs. Small Bowel Feeding (2011)

Citation:

White H, Sosnowski K, Tran K, Reeves A, Jones M. A randomised controlled comparison of early post-pyloric vs. early gastric feeding to meet nutritional targets in ventilated intensive care patients. Crit Care. 2009; 13(6): R187. Epub: 2009 Nov 25. PMID: 19930728.

PubMed ID: 19930728
 
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 compare outcomes in mechanically ventilated, critically ill patients in a MICU when they were fed by EN through gastric or post-pyloric access.

Inclusion Criteria:
  • 18 years of age or more
  • Expected to require mechanical ventilation 24 hours or longer.

 

Exclusion Criteria:
  • Ischemic bowel
  • Bowel obstruction
  • Exacerbation of inflammatory bowel disease
  • Acute variceal bleeding
  • At high risk for anastomotic leak.
Description of Study Protocol:

Recruitment

  • All eligible patients admitted to eight-bed MICU over 12-month period
  • Patients remained in the study until EN ceased or discharged from ICU.

Design

  • Single site, prospective randomized controlled trial
  • Randomization by computer-generated random number sequence and sealed opaque envelope. 

Blinding Used

Patients by several physicians; most were not involved in the study.

Intervention 

Gastric vs post-pyloric EN feeding tube: 

  • EN feeding algorithm and type of formula and goal rate determined by dietitian
  • Height used to estimate IBW; used adjusted body weight for obese patients
  • Algorithm prescribed 30kcal per kg IBW and  1.5g protein per kg IBW unless liver or renal failure was present, in which case protein was 1 to 1.2g per kg
  • EN initiated at 40ml per hour
  • Gastric feeding tubes aspirated for GRV every four hours; if GRV is less than 200ml, rate increased to target rate. If GRV is more than 200ml, a prokinetic agent was given (10mg metaclopramide initially and followed by erythromycin 250mg if large GRV continued. If GRV remained at more than 200ml, a post-pyloric feeding tube was inserted. If that was not tolerated, patient was given PN.

Statistical Analysis

  • Continuous variables reported as median and IQR and compared using Wilcoxon-rank sum test
  • Multiple regression model used to compare continuous outcomes of study with adjustments for baseline variables
  • Log transformation of positively skewed outcome data prior to regression analysis
  • Fisher's exact test to compare binary variables
  • Logistic regression to compare mortality rates in two groups
  • Primary analysis by intent-to-treat
  • Secondary per-protocol analysis was also completed
  • Sample size of 50 per treatment group estimated to have 90% power to detect halving of time to reach feeding goals at significance level of 5% and attrition rate of 10%
Data Collection Summary:

Timing of Measurements

Length of stay and mechanical ventilation (days).

Dependent Variables

  • Average daily energy deficit (kcal)  (Power analysis on this variable)
  • Time to initiate feeding (hours)
  • Time to reach goal from feeding initiation (hours)
  • Time to reach goal from admission (hours)
  • Average daily energy required (kcal)
  • Average daily energy deficit (kcal).

Independent Variables

Gastric or post-pyloric feeding tube placement.

Control Variables

APACHE II score (higher in post-pyloric group).

Description of Actual Data Sample:

Initial N

N=108:

  • Gastric group: N=57
  • Post-pyloric group: N=51.

Attrition (Final N)

104 intent-to-treat analysis:

  • Gastric group: N=54 (52% male)
  • Post-pyloric group: N=50 (48% male).

Age

  • Gastric median age: 54 (IQR 40 to 63)
  • Post-pyloric median age: 50 (IQR 45 to 70).

Other Relevant Demographics:

  • APACHE II scores (P<0.005)
    • Gastric: 24.5 (20 to 28)
    • Post-pyloric: 30 (25 to 35) 
  • LOS (P>0.05)
    • Gastric median: 5.02 (IQR 1.98 to 9.99)  
    • Post-pyloric median: 5.3 (IQR 2.73 to 9.89).

Location

Australia.

Summary of Results:

Key Findings

Early post-pyloric feeding offers no nutritional advantage over gastric feeding.

Variables

Gastric Group (N=54)

Median (IQR)

Post-pyloric Group (N=50)

Median (IQR)

Statistical Significance of Group Difference 
Time to initiate feeds (hours)

4.3 (2.9-6.5)

6.6 (4.5-13)

P=0.0002

Time to reach target feeding rate from admission (hours)

8.7 (7.6-13.0)

12.3 (8.9-17.5)

 P=0.3

Average daily energy deficit (kcal)

 73 (2-288)

167 (70-411)

 P=0.035*
Average daily protein deficit (g)

3.5 (0-15)

6.5 (2.8-17.3)

 P>0.11
Mortality (adjusted for APACHE II score) 5/54 (9.2%) 11/50 (22%) OR, 2.15 (95% CI: 0.65-7.07), P=0.2
VAP 11/54 (20%) 5/50 (10%) P=0.18
LOS (days) 4.97 (2.0-10.0) 5.57 (2.8-9.8) P>0.05
Mechanical ventilation (days) 3.43 (1.6-8.4) 4.92 (2.3-8.2) P>0.05

 *Not significant in multiple regression.

Author Conclusion:

Early post-pyloric feeding offers no advantage in nutritional intake or clinical outcomes.

Funding Source:
University/Hospital: Logan Hospital, University of Queensland, Australia
Reviewer Comments:
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? No
  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? 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.) 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? 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? 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