EAL

SCI: Caloric and Protein Needs in Acute and Rehabilitation Phases (2007)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To determine the applicability of the Harris Benedict equation in predicting energy requirements after acute SCI
To evaluate the accuracy of a 30-minute energy expenditure measurement to determine 24-hour requirements.

Inclusion Criteria:

Patients admitted to the surgical intensive care unit with respiratory dysfunction requiring extended mechanical ventilation after isolated SCI (tetraplegia, with lesions between C1 and C7).

Exclusion Criteria:

Closed head injury
Renal or hepatic dysfunction
Less than 18 years of age
Air leaks from chest tubes or endotracheal tubes.

Description of Study Protocol:

Recruitment

Patients admitted to the surgical intensive care unit after isolated SCI.

Design

Comparison of 24-hour measured resting and total energy expenditure with calculations (modified Harris Benedict equation) at one, two, three and four weeks post-injury in a group of ventilator-dependent tetraplegic SCI patients.

Intervention

Nutrition support based on predicted energy expenditure (HBEE): Harris Benedict equation modified to include an increment of 10% (activity factor for bed rest) and a 20% injury factor. Admission weight and height used in the equation and protein goal was estimated at 2g per kg admission body weight. Predicted equation was not altered during the four-week study period.

Statistical Analysis

One-way repeat measures analysis variance to compare serial data and all pairwise multiple comparison procedures (Tukey test)
Pearson product moment test to determine correlation coefficients.

Data Collection Summary:

Timing of Measurements

One, two, three and four weeks after injury.

Dependent Variables

Measured energy expenditure (MTEE and MREE): Indirect calorimetry using the Puritan Bennett 7250 Metabolic Monitor (integrated with the 7200ae ventilator, measured for a 24-hour period between post-injury days three to five and weekly thereafter
Respiratory Quotient: Puritan Bennett 7250 Metabolic Monitor
Calculated nitrogen balance: Formula N_in - (N_out+ 4).

Independent Variables

SCI level of injury within the C range.

Control Variables

Prealbumin (PAB)
UUN.

Description of Actual Data Sample:

Initial N: 11 males with tetraplegia and ventilator-dependent
Attrition (final N): 11
Age: mean range 32±8 years
Other relevant demographics: Healthy and well-nourished before injury
Anthropometrics: Mean admission weight: 86.9kg (range 63.5 to 130)
Location: Surgical intensive care unit, MetroHealth Medical Center, Cleveland, OH.

Summary of Results:

Variables	Week One (Mean ±SD) N=11	Week Two (Mean ±SD) N=10	Week Three (Mean ±SD) N=10	Week Four (Mean ±SD) N=7	Statistical Significance
Mean MTEE (kcal per day)	2468±449	2592±408	2425±434	2629±458	NS
Mean MREE (kcal per day)	2461±402	2628±381	2391±508	2647±425	NS
RQ	0.80±0.09	0.84±0.05	0.87±0.07	0.89±0.06	NS
Mean MTEE/HBEE (%)	96	100	95	95
Mean MREE/MTEE (%)	102	101	98	98

Other Findings

Mean body weight decreased by 9% over the study period
Patients received approximately two of three of MTEE and calculated protein requirements during the first two weeks, which improved to 100% or more by weeks three and four
UUN excretion was elevated at greater than 22g per day during the four-week period
Nitrogen balance remained negative over the study period
There was a positive trend in mean PAB (week one equals 13.7mg per dL; week four equals 31.3mg per dL).

Author Conclusion:

While there is a strong correlation between the modified Harris Benedict equation and 24-hour measured total energy expenditure, serial metabolic monitoring is recommended, when available, to account for individual variation
A resting energy expenditure measurement is adequate to determine daily calorie requirements
Visceral protein synthesis can be achieved despite a negative nitrogen balance
Further metabolic studies on this patient population that include correlation of energy requirements with the level of SCI in the acute phase are indicated
The present study confirms that SCI patients with complete lesions have increased energy requirements after injury.

Funding Source:

Reviewer Comments:

Small sample size
Subjects do not reflect the larger SCI population (those not on ventilators or not in the acute phase of SCI)
Some loss of subject follow-up during the four weeks
While subjects experienced negative nitrogen balance throughout the study, changes in body compartments were not assessed so the assumption (based on nitrogen balance) that patients lost lean body mass cannot be verified
Predicted energy expenditure (HBEE) was not altered during the four-week study period to reflect changes in body weight, because changes in body compartments couldn't be measured
All subjects were intolerant of gastric feedings intermittently during the first two weeks post-injury, and during this time received approximately two of three of MTEE and calculated protein requirements. During the last two weeks they received 100% of MTEE and calculated protein requirements.

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?		???
	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?	N/A
	2.3.	Were health, demographics, and other characteristics of subjects described?	???
	2.4.	Were the subjects/patients a representative sample of the relevant population?	???
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?	???
	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%.)	No
	4.3.	Were all enrolled subjects/patients (in the original sample) accounted for?	No
	4.4.	Were reasons for withdrawals similar across groups?	???
	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
	5.1.	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?		???
	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?	???
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	Yes
	6.6.	Were extra or unplanned treatments described?	No
	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?	???
	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?		???
	8.1.	Were statistical analyses adequately described and the results reported appropriately?	???
	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)?	???
	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?	???
	10.2.	Was the study free from apparent conflict of interest?	Yes