EE: Gas Collection Devices (2006)
Askanazi J, Silverberg PA, Foster RJ, Hyman AI, Milic-Emili J, Kinna JM. Effects of respiratory apparatus on breathing pattern. J Appl Physiol. (Respir Environ Exercise Physiol). 1980;48:577-580.
- Understand and give written consent
- Healthy adults.
- Refusal to consent
- Not meeting inclusion criteria.
- 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%)
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
- 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
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.
- Vt is increased 32.5% (p<0.001), f is not altered, and Ve is increased 31.3% (p<0.001)
- 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.
- “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.”
- 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.
- Statistical analysis (linear regressions) was not described in detail in methodology.
- Sampling methodology not described.
Quality Criteria Checklist: Primary Research
|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|
|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|