Ambulatory Gas Usage in Patients With Chronic Obstructive Pulmonary Disease and Exertional Hypoxemia
Bibliographic record
Abstract
In Brief PURPOSE Nonblinded observational studies have described the use of exertional supplemental oxygen in heterogeneous study populations. This report characterizes ambulatory gas usage among patients with chronic obstructive pulmonary disease (COPD) and exertional hypoxemia. METHODS Patients with COPD and exertional hypoxemia were included in blinded N-of-1 randomized controlled trials consisting of 3 pairs (oxygen and placebo) of 2-week treatment periods. Patient-reported and objective equipment measurements of cylinder and concentrator usage were collected. RESULTS Patients (N = 26) self-reported using gas for a median of 1.3 hours per day; measured equipment usage was 1.2 hours per day. Median concentrator use (0.8 hour per day) was significantly greater than cylinder use (0.5 hours per day) (P = .02). Patients may underestimate use by as much 1.9 hours per day or overestimate it by as much as 2.4 hours per day. The correlation coefficient between the magnitude of gas usage and the difference between the 2 estimates was 0.63 (P = .0006). As duration of gas use increased, the discrepancy between patient-reported usage and equipment gas usage increased. Below 2 hours per day, differences between patient-reported and equipment measurements were small. CONCLUSIONS Patients with COPD and exertional hypoxemia used little more than an hour of ambulatory oxygen daily, mostly from concentrators. Individual self-reported values are reasonably accurate under 2 hours per day but inaccurate for more prolonged use. This report characterizes ambulatory gas usage among patients with chronic obstructive pulmonary disease and exertional hypoxemia, using patient-reported and objective equipment measurements. About an hour of ambulatory oxygen was used daily. Individual reported values are reasonably accurate under 2 hours per day but inaccurate for more prolonged use.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.006 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".