The utility of spirometry and single breath gas transfer measurements to identify low total lung capacity
Bibliographic record
Abstract
Background Measurement of total lung capacity (TLC) requires large and expensive equipment. We aimed to investigate whether spirometric restriction and low alveolar volume measured by single breath gas transfer (V A) can be used to identify those with a low TLC. Methods We retrospectively analysed data from adults referred to Cambridge University Hospitals between January 2016 and December 2023. We investigated the utility of spirometric restriction (forced vital capacity (FVC) < lower limit of normal (LLN) with forced expiratory volume in 1 s /FVC ≥LLN) and reduced V A ( pleth V A to identify TLCpleth Results Data from 7923 patients were included. The majority (94%) of patients were of European ancestry, 51% were female. Mean age was 58 years. 11% of patients had a TLCpleth V A pleth pleth V A pleth V A pleth Conclusions A FVC in the healthy range is an effective tool for ruling out restriction. Low V A can be used to accurately identify those with a low TLC, negating the need for formal measurement of static lung volumes when identifying restrictive lung disease.
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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 | 0.019 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.004 | 0.002 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".