Reduced exercise ventilatory efficiency in adults with cystic fibrosis and normal to moderately impaired lung function
Bibliographic record
Abstract
Despite being a hallmark and an independent prognostic factor in several cardiopulmonary diseases, ventilatory efficiency—i.e., minute ventilation/carbon dioxide output relationship (V̇e/V̇co2)—has never been systematically explored in cystic fibrosis (CF). To provide a comprehensive frame of reference regarding measures of ventilatory efficiency in CF adults with normal to moderately impaired lung function and to confirm the hypothesis that V̇e/V̇co2is a sensitive marker of early lung disease. CF patients were divided into three groups, according to their spirometry: normal (G1), mild impairment (G2), and moderate impairment (G3) in lung function. All participants underwent incremental cardiopulmonary exercise testing on a cycle ergometer. Lowest V̇e/V̇co2ratio (nadir) and the slope and the intercept of the linear region of the V̇e/V̇co2relationship were contrasted in a two-center retrospective analysis, involving 72 CF patients and 36 healthy controls (HC). Compared with HC, CF patients had significantly higher V̇e/V̇co2nadir, slope, and intercept ( P < 0.001, P < 0.001, and P = 0.049, respectively). Subgroup analysis revealed significant differences in nadir ( P = 0.001) and slope ( P = 0.012) values even between HC and G1. Dynamic hyperinflation related negatively with slope ( P = 0.045) and positively with intercept ( P = 0.001), while no impact on nadir was observed. Ventilatory inefficiency is a clear feature of adults with CF, even among patients with normal spirometry. V̇e/V̇co2nadir seems to be the most reliable metric to describe ventilatory efficiency in CF adults. Further prospective studies are needed to clarify whether V̇e/V̇co2could represent a useful marker in the evaluation of early lung disease in CF. NEW & NOTEWORTHY This is the first study to investigate ventilatory efficiency in a cohort of adult cystic fibrosis (CF) patients with nonsevere lung disease. The finding of impaired ventilatory efficiency in patients with normal lung function confirms the higher sensitivity of exercise testing in detecting early lung disease compared with spirometry. Dynamic hyperinflation plays a significant role in determining the behavior of V̇e/V̇co2slope and intercept values with increasing lung function impairment. Apparently free from interference from mechanical constraints, V̇e/V̇co2nadir seems the most reliable parameter to evaluate ventilatory efficiency in CF adults.
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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 | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 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".