EE: Application of RQ (2005)

Citation:

Delafosse B, Viale JP, Pachiaudi C, Normand S, Goudable J, Bouffard Y, Annat G, Bertrand O. Long-and medium-chain triglycerides during parenteral nutrition in critically ill patients. Am J Physiol. 1997;272 (Endocrinol Metab 35): E550-E555.

 
Study Design:
Repeat measures crossover
Class:
C - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:
  1. To examine the change in substrate oxidation rates in pats experiencing hyperglycemia and hyperinsulinemia when the lipid nutritional support was shifted from LCT to a mixture of MCT and LCT.

Definitions

  • Steady state: None provided
Inclusion Criteria:
  1. Understand and give written consent
  2. Diseases in subjects that were allowed: major surgical procedure of esophageal carcinoma resection
    [Analyst note: the 8 pt with orthotopic liver transplantation was not abstracted d/t sample size not large enough]
  3. Medications allowed: low-dose heparin to prevent thromboembolism.
Exclusion Criteria:
  1. Refusal to consent
  2. Not meeting inclusion criteria
  3. Diseases in subjects that were excluded: diabetes, sepsis, renal insufficiency, major hepatic dysfunction
Description of Study Protocol:

3-day study; 1st post-op day was on controlled mechanical ventilation and the next day changed to pressure-assisted ventilation. REE measured 1st post-op day.

ANTHROPOMETRIC

  • Ht measured? Likely
  • Wt measured? Likely

CLINICAL

Arterial blood sampled at the end of each day.

  • Monitored heart rate? Likely
  • Body temperature? Likely
  • Medications administered? Likely

Resting energy expenditure

  • IC type: Douglas bag with mass spectrometer attachment
  • Equipment of Calibration: not specified
  • Coefficient of variation using std gases: No
  • Rest before measure (state length of time rested if available): post-operative
  • Measurement length: 12 hours
  • Steady state: 12-hour measure ruled out any daytime variation
  • Fasting length: on continuous parenteral nutrition
  • Exercise restrictions XX hr prior to test? Not applicable
  • Room temp: Not specified
  • No. of measures within the measurement period: 1-continuous each time
  • Were some measures eliminated? Not likely
  • Were a set of measurements averaged? Yes, measures over 12 hours
  • Coefficient of variation in subjects measures? Not specified
  • Training of measurer? Not specified
  • Subject training of measuring process? No

DIETARY

Administered 6 gm glucose/kg body wt/day. During the 2 subsequent days, total calorid intake was set at 1.5 time measured REE. Nitrogen intake 17.2% of total kcals; non-protein intake was provided as 50% glucose and 50% lipids. Lipids were randomly administered for 24-h either as a LCT emulsion or as an MCT-LCT emulsion.

Data Collection Summary:

Outcome(s) and other measures

  1. Measured REE [(VO2 l/min), VCO2 (l/min; ml/kg/min), RQ, ventilation (l/min)].
  2. Blood sampled for glucose, free fatty acids, ketone bodies, insulin
  3. Urine sample for nitrogen
  4. Independent variables of weight, height, age, BMI,and fat-free mass, fat mass

Blinding used: No

Description of Actual Data Sample:
  • N=12 s/p esophageal carcinoma resection
  • Mean age, y: 63±2
  • (gender not specified)

Statistical tests

Means ±SE; paired t-test for type of lippid on pulmonary gas exchange; No between-group comparisons made

Summary of Results:

ANTHROPOMETRIC

Mean±SE
Wt, kg 73±2
Wt, % 1.08±0.03

INDIRECT CALORIMETRY DATA

Esophageal carcinoma (n=12) LCT MCT-LCT

VCO2 ml/min

193±6      207±10

VO2 ml/min

220±11     235±10

RQ

0.876±0.009  0.878±0.045

VO2and VCO2were not significantly influenced by the type of lipid administered. Although VO2increased by 7% in esophageal carcinoma group after MCT-LCT emulsion infusion, this change did not reach statistical significance (P=0.06).

[Assuming normality, 98% of individuals fall within the RQ range of 0.814-0.938 for continuous parenteral nutrition with LCT and 0.566-1.2 for continuous parenteral nutrition with MCT+LCT.

Calculations  
PN with LCT v12 X 0.009 =0.031 (1 SD) 0.031 X 2 =0.06 (2 SD)
PN with MCT + LCT v12 X 0.045 =0.156 (1 SD)

0.156 X 2 =0.312 (2 SD)

Author Conclusion:

As stated by the author in body of report

The current findings fail to demonstrate any enhancement of lipid oxidation rate when nutritional supplementation was shifted from LCT to MCT-LCT mixture in patients after major surgery experiencing hyperglycemia and hyperinsulinemia.”

“Neither the glucose nor the lipid oxidation rates were modified by the introduction of MCT into the diet in hyperglycemic and hyperinsulinemic patients after esophageal surgery.

“The length of measurement data was likely to rule out other potential sources of errors bound to indirect calorimetry, namely variation of CO2stores and accumulation or loss of intermediary metabolites.”

“It was supposed that administered lipids were not stored and that the patients did not burn their endogenous lipids. The latter hypothesis could be questionable because several studies suggest that parenterally administered lipids may serve mainly to preserve endogenous fat stores in burn pt or in critically ill patients.”

“In conclusion, in critically ill patients experiencing hyperglycemia and hyperinsulinemia, shifting a part of 24-h LCT administration to MCT did not modify lipid or glucose oxidation rate or the nitrogen balance.
Funding Source:
Government: Ministere de l'Education Nationale de l'Enseignementer et de la Recherche (France)
University/Hospital: Hopital Edouard Herriot, Institut National de la Sante et de la Recherche Medicale (France)
Reviewer Comments:

Strengths

“Formulas for calculating oxidation rates provided; shoichiometry of the oxidative reactions of each TG contained in the LCT or MCT-LCT emulsions were completed”

“Studied homogenous: pt undergoing esophageal carcinoma resection”

Generalizability/Weaknesses

“Generalizable to older adult pt undergoing esophageal carcinoma resection who are on pressure-assisted ventilation

Study biases include an intervening variable not measured presence of sepsis not discussed;

Do not know prior weight loss or when weight taken (pre- or post-op?); group mean weight percent was 1.08% which interpreted would mean that ~1 person was above “normal” body weight?

Did not provide room temperature and information about training of the person who completed IC measures; Also, difficult to determine if Douglas bag used in measure since they cite the “machine protocol” but this may refer only to the spectrometer

“Use Rosa and Shizgal estimation formula
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? N/A
  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? No
  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? Yes
  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