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EE: Rest Period Duration (2013)

Citation:

Swinamer DL, Phang PT, Jones RL, Grace M, Garner King E. Twenty-four hour energy expenditure in critically ill patients. Crit Care Med. 1987;15(7):637-643.

 
Study Design:
Observational
Class:
D - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:
  1. Measure cumulative 24-h energy expenditure.

Definitions

  • Rest: Patient lying motionless and apparently comfortable, with eyes open or closed after 30 min post-even rest
  • Post-event: Some activity such as repositioning or chest physiotherapy
  • Agitation or restlessness: Patient appearing uncomfortable, grimacing, or moving body limbs, w/o purpose.
Inclusion Criteria:
  1. Mechanical ventilation FIO2<0.60
  2. Critically ill
  3. Admission into Univ Alberta Hospital.
Exclusion Criteria:
  1. Refusal to consent
  2. Not meeting inclusion criteria.
Description of Study Protocol:

ANTHROPOMETRIC

  • Ht measured? Not specified
  • Wt measured? Not specified.

CLINICAL

  • APACHE II scores 23±7 (severely ill); 50% mortality of pt population studied
  • Medication use varied; 1 pt did not receive any; 9 received morphine sulfate (IV or meeds); Other pt received analgesics and sedatives, prn.

Resting energy expenditure

  • IC type: Portable Gould 9000IV;
  • Equipment of Calibration: Yes
  • Coefficient of variation using std gases: Reported % accuracy
  • Rest before measure (state length of time rested if available): On ventilator;
  • Measurement interval: Analyzes every 30 seconds; provides minute readings
  • Measurement length: 20.75±0.75 h/day
  • Steady state: No
  • Fasting length: No
  • Exercise restrictions XX hr prior to test? NA
  • Room temp: Hospital air
  • No. of measures within the measurement period: Several
  • Were some measures eliminated? No
  • Were a set of measurements averaged? Yes
  • IF avg, identify length of each measure & no. of measurements? Entire day measures
  • Coefficient of variation in subjects measures? No
  • Training of measurer? Not stated; Likely
  • Subject training of measuring process? NA.

DIETARY

  • Nutrient infusion (enteral or parenteral) remained constant during 24-h.
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. Predicted RMR using: HB
  3. Independent variables: Nutrient intake; APACHE score, spesi score; PEEP, FIO2

Blinding used: No.

Description of Actual Data Sample:
  • N=10; 8 M, 2 F
  • Mean age: 63+15 y
  • Studied 7±4 days after ICU admission.

Statistical tests

  • Mean ±SD
  • Student’s t-test
  • P<0.05 significant.
Summary of Results:

Mean+SD  Range
Energy, kcal  1716+731  264-2400
Energy, predicted using Harris-Benedict, kcals  1501±202  1085-1770
Energy, resting measured, kcals  2192±334  1706-2761
Energy, TOTAL measured, kcals  2342±371  1793-2997

  • The degree to which resting energy expenditure exceeded predicted EE correlated significantly with admission APACHE II score (r=0.64, p<0.02)
  • Mean Measured resting energy expenditure published in Table 3 (Analyst note mean measured REE of 2192±334 kcals did NOT match text 2186±343 kcals; verified using EXCEL and Table 3 is accurate); Therefore, measured REE was 47.3% above predicted REE using Harris-Benedict.
  • Total EE averaged 2342±371 [Analyst note: Text erroneously reported 2242±371] and represented a negative energy balance of -626 kcal/d (the correct value)]
  • During the activities (where each activity and the amount of time to complete it was measured) and expressed as a proportion of REE), weighing the pt on a sling bed type scale, repositioning, and chest physiotherapy incurred 36±12%, 31±11%, and 20±10% increases above REE. Although certain activities caused considerable elevations in EE, contribution to total daily EE was small because of short duration. 
  • During the 30 min after an activity (postevent resting EE), on average, energy expenditure increased by 5.8%±4.3%.
Author Conclusion:
  • Several factors most likely contribute to the discrepancy in REE in critically ill pt:  nutrient intake, sedation and/or analgesia, and degree of stress and illness. Weissman (Chest, 1984) indicates finding an initial reference state from which to calculate the EE for the critically ill pt is a difficult task. In our study, measured REE was 47.3% above predicted EE by Harris-Benedict.
  • “[In 2 patients], the periods during which they received larger amounts of sedatives were associated with a significant (P<0.05 decrease in EE)."
  • “To further emphasize the importance of sedation on EE, 8 of 10 pt averaged 3.3±1.9 h of agitation and/or restlessness during 24-h and represented 15.0±8.2% contribution to total EE.”
  • “Although large EE increases above REE were observed during various activities, their contributions to TEE was relative small; the range of increase above REE was 1.4-10.6%”
  • “For this study, it appears that an activity factor of 10% above REE measures should adequately meet the EE associated with routine ICU activities.” 
  • “Actual REE should be measured before the 10% activity factor is applied.”
  • “One limitation of our study is no distinction was made between EE during sleep and rest.”
Funding Source:
Not-for-profit
1
Reviewer Comments:

Strengths

  • Categorized severity of illness through APACHE II and sepsis scores
  • Calibrated IC machine with great detail.

Generalizability/Weaknesses

  • “Did not define steady state;” and training of measurer
  • “Study biases include non-randomized sample so a selection bias"
  • An intervening variable not measured dehydration and weight loss changes; lean muscle mass and fat mass
  • Difficult to apply findings to Conclusion statement due to text not matching Table 3; In addition, the length of time for each activity is not reported and so a mean of a 5 min procedure v. mean of a 30 min procedure is proportionately different on RMR (Fig 2A). YET, the contribution toward 30 min post-event rest may be significantly different and cannot be detected by the reporting.
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? 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? 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? No
  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? No
  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