EAL

EE: Application of RQ (2005)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

Document a specific situation in which the straightforward procedure for assessing REE of pt on respirators, especially those with positive-end expiratory pressure produced large overestimations of REE.

Definitions

Steady state: repetitive values were obtained

Inclusion Criteria:

Not applicable.

Exclusion Criteria:

Not applicable.

Description of Study Protocol:

ANTHROPOMETRIC

Ht measured? Likely
Wt measured? Likely
Fat-free mass measured? Not specified

CLINICAL

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

On Day 1, laparotomy

Status p/op: 2^nd laparotomy for bile and intra-abdominal abscesses
Day 5 post 2^nd Sx: Transferred to another hospital for necrotic right liver lobe and was resected.
Sepsis persisted, ARDS developed and required ventilatory support.
Venitlatory support included: Pavulon administration FiO₂up to 100% and PEEP up to 25 cm H²).
Chronic pulmonary insufficiency and anoxi cerebral damage occurred.
IC measures reported were 40 days post-injury and when pt had stabilized

Resting energy expenditure

IC type: MMC Beckman
Equipment of Calibration: Yes
Coefficient of variation using std gases: No
Rest before measure (state length of time rested if available): Yes Bedridden
Measurement length: Not specified but until “steady state (repetitive) values were obtained
Steady state: Yes
Fasting length: On nutritional support
Exercise restrictions XX hr prior to test? Not applicable
Room temp: hospital temperature
No. of measures within the measurement period: 1
Were some measures eliminated? Yes
Were a set of measurements averaged? Yes
IF avg, identify length of each measure & no. of measurements? Not specified
Coefficient of variation in subjects measures? Not applicable since illness varied day-to-day
Training of measurer? Likely
Subject training of measuring process? With repeated measures.

DIETARY

On nutritional support
Intervening factor:

Data Collection Summary:

Outcome(s) and other measures

Measured REE [(VO₂ l/min), VCO₂ (l/min; ml/kg/min), RQ, ventilation (l/min)].

Blinding used: No

Description of Actual Data Sample:

1 19-year old female patient involved in a motorcycle accident

Statistical tests

Simple regression analysis and ANOVA to determine if fluctuation of RMR was significant over the range of RQ obtained; general linear test.

Summary of Results:

ANTHROPOMETRIC

No anthropometric data given

INDIRECT CALORIMETRY DATA

[Analyst note: Of the 19 day data provided, first and last data points plus intermediary day data abstracted in table below; then entire data summarized after table.]

	VO₂	vCO₂	RQ	FiO₂	PEEP
9/23	448	220	0.49	65	20
10/6	466	174	0.37	70	20
10/8	809	255	0.32	70	15
10/24	645	343	0.53	40	7
11/12	267	273	1.02	40	5
11/13	259	213	0.82	40	5

	REE O₂	REE VCO₂
9/23	3116	1749
10/6	3241	1383
10/8	5627	2027
10/24	4486	2726
11/12	1857	2170
11/13	1801	1693

[Note: REE: O₂estimation = VO₂X 4.83; REE VCO₂estimation = VCO₂X 5.52.]

There was a significant increase in estimated REE using VO₂as RQ fell below known physiologic levels (P<0.01); although the metabolic situation was unchanged, the REE was excessive when RQ fell below normal levels as a result of a chest tube leak.
There was no significant increase or decrease in REE computed using VCO₂over the entire range of RQ indicated by the poor coefficient of determination (r²=0.11).

[Note: The linear changes in REE using VO₂and VCO₂were 4408 and 443 kcal, respectively. (i.e., Equation slope = change in REE from a RQ of 0.0 to 1.0).]

On 11/12, there were four indirect calorimetry measures while pt was on continuous positive airway pressure of 5 cm H20 and FiO₂of 40) and the RQ ranged from 0.78 to 1.02. If use of O₂estimation REE ranged from 1857 (when RQ was 1.02) to 2400 kcal (when RQ was 0.78).
On this same day, if use of CO₂to estimate kcal expenditure, REE ranged from 2083 to 2321 kcal/day (and RQ values were 0.80 and 0.98, respectively).
There was a significant difference between the two regression lines obtained when computing REE using BOTH VO₂and VCO₂ (P<0.01).
If REE data is compared over only the normal range of RQ, there is no significant difference in using VO₂or VCO₂ (F=0.67).

Author Conclusion:

As stated by the author in body of report

“An RQ above 1.0 can be explained by a net synthesis of fat from CHO or a washout of CO₂ but an RQ below 0.6 is usually indicative of a system error . . . this was considered but rejected after inspection and scrutiny revealed no abnormality in the system.”

“The possibility of oxygen leaking out of the lungs to produce a VO₂in excess of actual volume of oxygen “consumed” for metabolic purposes was considered and substantiated by appearance of subcutaneous emphysema and continuous air leak from the chest tubes.”

“In patients with air leaks, a high FiO₂worsens the ability to calculate REE using VO₂ . . the REE can be estimated more accurately by using the VCO₂instead of VO₂ as the amount of CO₂lost is substantially less under these circumstances (FiO₂= 40-70% FeCO₂= 2-4%). [Our data] supports that although CO₂and O₂leaked out of the lungs, the relative amount of O₂lost at 40-70% concentration would be substantially more than CO₂at 2 to 4% concentration. Using VCO₂to estimate REE produces a more accurate estimation.

To determine REE (kcal/day) = VCO₂ (ml/min) X 1/1000 (liter/ml) X 1440 (min/day) X 5.52 (kcal/liter) . . . This approach estimates a minimum REE rather than a maximum REE and calories can be administered to the pt without the possibility of administering an excessive caloric load.

The above approach provides alternatives in estimating energy needs in patients on respirators where a real RQ (no system or instrument error ) falls below 0.6. . and would not overestimate the caloric need as the use of VO₂would.”

Funding Source:

University/Hospital:

Michigan State University, Butterworth Hospital

Reviewer Comments:

Strengths

“Provides a case where use of RQ to determine kcal/day needs in a stressed patient becomes very important when a “true” RQ falls below the normal range of 0.7-1.0.”

Generalizability/Weaknesses

“Retrospective chart analysis provides unique patient care course”
“Intervening variables that are not reported include medication use, temperature changes related to sepsis, weight and lean muscle mass changes as a result of sepsis and high stress”
Linear slope RQ changes from 0 to 1.0 may not be appropriate since an RQ is not physiological possible?
Indirect calorimetry measurement technique descriptions very limited and refers to Beckman instrument manual. Unclear if 4 measures taken on 11/12 were repeated tests to determine IC measurement protocol accuracy or if taken throughout the day to reflect a change in patient condition.

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
	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
	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
	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
	4.	Is the intervention or procedure feasible? (NA for some epidemiological studies)	Yes

Validity Questions
	1.	Was the research question clearly stated?	Yes
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
	1.1.	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
	1.2.	Was (were) the outcome(s) [dependent variable(s)] clearly indicated?	N/A
	1.3.	Were the target population and setting specified?	N/A
	1.3.	Were the target population and setting specified?	N/A
	2.	Was the selection of study subjects/patients free from bias?	N/A
2.	Was the selection of study subjects/patients free from bias?		N/A
	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
	2.1.	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
	2.2.	Were criteria applied equally to all study groups?	N/A
	2.3.	Were health, demographics, and other characteristics of subjects described?	N/A
	2.3.	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
	2.4.	Were the subjects/patients a representative sample of the relevant population?	N/A
	3.	Were study groups comparable?	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
	3.1.	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
	3.2.	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
	3.3.	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
	3.4.	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
	3.5.	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
	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?	N/A
4.	Was method of handling withdrawals described?		N/A
	4.1.	Were follow-up methods described and the same for all groups?	N/A
	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
	4.2.	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
	4.3.	Were all enrolled subjects/patients (in the original sample) accounted for?	N/A
	4.4.	Were reasons for withdrawals similar across groups?	N/A
	4.4.	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
	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?	N/A
5.	Was blinding used to prevent introduction of bias?		N/A
	5.1.	In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate?	N/A
	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
	5.2.	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
	5.3.	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
	5.4.	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
	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?	No
6.	Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described?		No
	6.1.	In RCT or other intervention trial, were protocols described for all regimens studied?	N/A
	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
	6.2.	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
	6.3.	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
	6.4.	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
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	N/A
	6.6.	Were extra or unplanned treatments 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
	6.7.	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
	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.	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
	7.1.	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
	7.2.	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
	7.3.	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
	7.4.	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
	7.5.	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
	7.6.	Were other factors accounted for (measured) that could affect outcomes?	N/A
	7.7.	Were the measurements conducted consistently across groups?	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.	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
	8.1.	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
	8.2.	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
	8.3.	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
	8.4.	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
	8.5.	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
	8.6.	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
	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.	Are conclusions supported by results with biases and limitations taken into consideration?		Yes
	9.1.	Is there a discussion of findings?	N/A
	9.1.	Is there a discussion of findings?	N/A
	9.2.	Are biases and study limitations identified and discussed?	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.	Is bias due to study's funding or sponsorship unlikely?		No
	10.1.	Were sources of funding and investigators' affiliations described?	N/A
	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
	10.2.	Was the study free from apparent conflict of interest?	N/A