CI: Calorie/Energy Needs (2007)


 Dvir D, Cohen J, Singer P. Computerized energy balance and complications in critically ill patients: An observational study. Clinical Nutrition. 2006 25:37-44.

PubMed ID: 16321459
Study Design:
Case Study or Case Series
D - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
The purpose of the study was to measure the cumulative energy balance in critically ill patients receiving mechanical ventilation using a bedside computerized information system (CIS), and an indirect calorimetry, and to assess its impact on patient outcome.
Inclusion Criteria:
Patients requiring at least 96 hours of mechanical ventilation who were admitted to the ICU of Rabin Medical Center between October 2002 and May 2003.
Exclusion Criteria:
Patients who received a fraction of inspired oxygen of >60% at the time of indirect calorimetry or who had air leaks around the respiratory circuit, patients with chest tubes, patients with hemodynamic instability and those younger than 18 years were excluded.
Description of Study Protocol:


  • all patients requiring at least 96 hours of mechanical ventilation who were admitted to the mixed ICU (surgical, medical, trauma or burn patients) of Rabin Medical Center between October 2002 and May 2003 were studied


  • prospective, observational, case series (correlational)
  • used indirect calorimetry and a bedside computer information system to measure REE and daily macronutrient intake from all sources

Blinding used: N/A

Intervention: N/A

Statistical Analysis Means ± standard deviations presented.  Differences in patient anthropometric, biochemical values, nutritional status indices and clinical outcome compared by one-way analysis of variance.  Pearson correlation coefficients were used to assess the relationship among energy requirement, nutrient intake and clinical outcome.  (p value of < 0.05 was considered statistically significant.  A one-and two-way analysis of variance with data screening was used.  Data were fitted to a multivariate logistic regression model to identify independent predictors and stepwise logistic regression for predicted probability used.


Data Collection Summary:

Timing of Measurements

  • indirect calorimetry performed daily (at least 6 days/week) while in intensive care. Enteral feedings not stopped during measurement.
  • daily use of computer information system to determine mean cumulative energy balance

 Dependent Variables

  • mortality: Death from any cause during ICU stay or hospitalization
  • morbidity (acquired organ dysfunction, pressure sores and/or need for surgery)
  • secondary outcome measures: ICU length of stay (in days), 2) need for respiratory support (LOV) and occurrence of new complications by organ occuring as a new onset during hospitalization determined as:  renal failure, need for renal replacement therapy; cardiovascular disease with need for new inotropic or vasopressor support; acute lung injury with partial arterial oxygen tension/fractured concentration of oxygen in inspired gas of <250mmHg; liver failure with hyperbilirubinemia; severe sepsis or septic shock according to criteria of teh American College of Chest Physicians/Society of Critical Care Medicine Consensus Conference.   

 Independent Variables

  • resting energy expenditure measured daily with indirect calorimetry
  • daily macronutrient intake measured with a bedside CIS connected to all caloric sources (enteral or parenteral nutrition, enteral and IV fluids containing calories). 



Description of Actual Data Sample:

Initial N: 50 patients (33 men, 17 women)

Attrition (final N): N/A

Age: mean 59 years ±18

Ethnicity: not reported


  • BMI (kg/m2) mean 26.9 ± 5


  • APACHE II score (23.1 ± 7)

Location: General Intensive Care Department of Rabin Medical Center, Israel.


Summary of Results:

Energy Balance Summary
Criteria Mean Range
Energy Intake/ 24 hrs 1512 kcal/24 hr 400 - 3210 kcal/24 hr
Mean Energy Balance/ 24 hrs -460 kcal/24 hr -1025 to+ 259 kcal/24 hr
Mean Cumulative Energy Balance -4767 kcal/24 hr

-10,000 kcal in 11 patients

between -4000 to -1000 kcal in 15 patients

> - 4000 kcal in 24 patients


Correlation between Morbidity and Energy Balance


Cumulative Energy Balance

 (P value)

Maximum Negative Energy Balance

(P value)

Adult Respiratory Distress Syndrome






Renal failure



Renal replacement therapy









Norepinephrine use



Pressure sore



Total complications



No significant association was found between cumulative nor maximum negative energy balance and days on ventilator, length of ICU stay, length of hospital stay or mortality (overall death rate was 46%).


Author Conclusion:
Use of a computerized information system is helpful in calculating energy balance when combined with daily indirect calorimetry. Critically ill patients have significant negative energy balance in the first days of ICU stay. Prospective studies are needed to determine whether morbidity will be decreased with tight energy balance control.
Funding Source:
University/Hospital: Rabin Medical Center (Israel), Sackler Faculty of Medicine Tel Aviv University (Israel)
Reviewer Comments:
Correlational, observational study indicating interesting results on negative energy balance and the occurrence of complications in the ICU.
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? 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? Yes
  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? Yes
  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? Yes
  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? Yes
  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? 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? 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)? N/A
  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? No
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