Limitations of regional ventilation inhomogeneity indices in children with cystic fibrosis
Bibliographic record
Abstract
Abstract Background S cond is a multiple breath washout (MBW) index that measures convection‐dependent ventilation inhomogeneity (CDI) arising within conductive airways, but the calculation method is unreliable in subjects with advanced cystic fibrosis (CF) lung disease. A new CDI index, S cond *, has been proposed for use in adults with CF and moderate to severe ventilation inhomogeneity. We aimed to evaluate the most appropriate CDI index in children and adolescents with CF and various degrees of inhomogeneity, and from that the most appropriate diffusion‐convection‐interaction index (S acin or S acin *). Methods S cond , S acin and the alternative indices, S cond *, and S acin * were retrospectively calculated in subjects with CF aged 3 to 18 years and age‐matched controls, who underwent sulfur hexafluoride MBW between 2003 and 2015. The upper limit of normal was based on 95th percentile of the control population. Results One hundred and twenty‐seven subjects with CF (44% male; mean age ± SD: 7.5 years ± 4.9) and 94 controls (53% male; 7.9 years ± 5.1) were included in the final analysis. All measures of ventilation inhomogeneity were significantly higher in children with CF. As predicted, S cond reached a maximum value at lung clearance index (LCI) values of approximately 9. In subjects with LCI ≥ 9 S cond * showed good correlation with LCI, whilst S cond had no relationship with LCI (Spearman rank correlation S cond */LCI, 0.49; P < .01; S cond /LCI, −0.068; P = .46). In subjects with mild disease (LCI < 9) S cond was more frequently abnormal than S cond * (37% vs 16%; P = .01). Conclusions S cond and S acin are sensitive indices of early regional inhomogeneity, but are of no value when LCI ≥ 9. In these subjects, S cond * & S acin * are potential alternatives.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".