Oxygen supplementation in ambulatory patients with heart failure: a randomized proof-of-concept study
Bibliographic record
Abstract
Abstract Aims The aims of this study were to describe the short-term effects of oxygen therapy on the physiological response and symptoms during ambulation in patients with chronic heart failure (HF). Methods and results In this pilot, cross-over, randomized study, subjects with chronic HF underwent two 6-min walk tests (6MWTs) on the same day. They were randomized to either receive oxygen through a portable oxygen concentrator (POC ON) during the first test and no oxygen (POC OFF) during the second test, or vice versa. Endpoints included (i) peripheral oxygen saturation, (ii) heart rate, and (iii) modified BORG scale. A linear mixed model for repeated measures was used for comparisons. A total of 20 participants were included, aged 70 ± 10 years, with the mean left ventricular ejection fraction 33% ± 10% and N-terminal pro-B-type natriuretic peptide 1115 ± 1625 pg/mL. There was no difference in distance walked with or without oxygen supplementation. Oxygen saturation during 6MWT was higher with POC ON [3 min, SpO2 + 3.4%, 95% confidence interval (CI) 1.8–5.0%; 6 min, + 2.8%, 95% CI 2.2–3.3%]. Heart rate recovery tended to be better in patients with POC ON (difference 7.4 b.p.m., 95% CI −2.4 to 17.2). Perceived exertion and fatigue were significantly lower with POC ON during exercise (3 min, −0.7, 95% CI −1.2 to −0.2; 6 min, −0.75, 95% CI −1.1 to −0.4; and 3 min into recovery, −0.5, 95% CI −0.8 to −0.2). Conclusion Our results suggest that for a same amount of physical activity, supplemental oxygen can improve peripheral oxygen saturation and breathlessness in symptomatic patients with chronic HF.
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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 | 0.006 | 0.004 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.005 | 0.003 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.003 | 0.002 |
| Insufficient payload (model declined to judge) | 0.007 | 0.001 |
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".