Feasibility and Utility of Multiple Breath Washout Measured Scond and Sacin in Preschool Children With Cystic Fibrosis
Bibliographic record
Abstract
BACKGROUND: The lung clearance index (LCI) is a sensitive measure of global ventilation inhomogeneity but does not describe the gas mixing mechanisms that lead to inhomogeneity. Multiple breath washout normalized phase III slope (SnIII) metrics may complement LCI when assessing lung disease; Scond describes convection-dependent inhomogeneity and Sacin reflects diffusion convection-interaction-dependent inhomogeneity respectively. We aim to determine the feasibility and utility of Scond and Sacin in preschool children with CF. METHODS: We retrospectively assessed Scond and Sacin in successful MBW tests performed on preschool children. Scond and Sacin were calculated by visual breath-by-breath analysis according to ATS/ERS MBW consensus statement, with the exception that minimum SnIII was at least 30% of expired volume rather than between 65% and 95% of expired volume. RESULTS: We analyzed MBW tests for 40 healthy controls and 40 participants with CF, with a mean (range) baseline age of 4.1 years (2.6-5.9). Of the 372 successful MBW tests analyzed, 77% had reportable SnIII indices. Scond was elevated in CF relative to controls (∆ 0.037; 95% CI: 0.026-0.047; p < 0.001). Both within- and between-test variability was higher for Scond and Sacin than for LCI. More clinically stable test occasions were above the upper limit of normal for Scond than for LCI (64% vs. 50%, p = 0.02). CONCLUSIONS: MBW metrics Scond and Sacin are feasible in young children. While they differentiate preschool children with CF from healthy controls, SnIII indices are more variable than LCI, limiting their interpretability.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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".