EE: Gas Collection Devices (2006)
Citation:
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To study the effect of respiratory apparatus on breathing pattern.
Inclusion Criteria:
- Understand and give written consent
- Healthy adults.
Exclusion Criteria:
- Refusal to consent
- Not meeting inclusion criteria.
Description of Study Protocol:
- Subjects were studied in the canopy with a) a mask (m), b) mouthpiece plus noseclip (mp+nc), and c) without any attachments to the face or airway.
- Each run began when the subject showed a stable level of VO2 and VCO2. (about 10-15 min)
- Each run lasted 30 min to 1 h and represents an analysis of 400-900 breaths.
Resting energy expenditure
The validation of the canopy was by having subjects breath through a mouthpiece and pneumotachograph while in the canopy, thus allowing a comparison of the tracing obtained by the canopy with that of the pneumotachograph. (within ±2%)
Data Collection Summary:
Outcome(s) and other measures
- O2 consumption, CO2 consumption, tidal volume (Vt), frequency (f), minute ventilation, mean inspiratory flow, inspiratory and expiratory time (Ti and Te)
Blinding used: Yes
Description of Actual Data Sample:
Overall
- N=28 (16 males and 12 females)
- Mean age=27 (range 22-36)
- No smoking Hx
Subjects in which Ti, Te and Vt/Vi were measured
- N=12 (6 males and 6 females)
- Statistical tests
- Means±SD, linear regression
Summary of Results:
Measurements made with the canopy in the group of 12 subjects (in whom Ti, Te, and Vt/Vi were measured) were not significantly different from the overall group. Changes in Vt, f, and Ve in this group caused by mask and mp+nc were not significantly different from those in the overall group.
Mask (n=28)
- Vt is increased 32.5% (p<0.001), f is not altered, and Ve is increased 31.3% (p<0.001)
Mouthpiece+noseclip (n=28)
- Vt is increased 15.5% (p<0.01), f remains unchanged, and Ve increased 14.1% (p<0.01)
Canopy only (n=28)
- Canopy used as comparison measures for other 2 gas collection devices
- No significant change in VO2, VCO2, or sign frequency were seen.
Author Conclusion:
- “The use of mask or mouthpiece plus noseclip is a common practice in the study of respiration. Our data indicate that this type of apparatus induces an increase in both tidal volume and minute ventilation.”
- “The increase in tidal volume induced by the respiratory was 2ndary to an increase in mean inspiratory flow. Inspiratory duty cycle (Ti/Ttot) was unchanged by either mask or mp+nc.”
Funding Source:
Government: | NIH |
Reviewer Comments:
Strengths
- Comprehensive description of the canopy-computer-spirometry system/program used in the study.
- Measurements validation was done properly.
- Study design meets the objective of the study.
- Have comparison groups to study the different effects of apparatus on breathing pattern in people using canopy system.
Generalizability/Weaknesses
- Statistical analysis (linear regressions) was not described in detail in methodology.
- Sampling methodology not described.
Quality Criteria Checklist: Primary Research
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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? | 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.) | 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? | No | |
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 | |