Oscillating inspiratory flow limitation during Cheyne-Stokes hyperpnoea
Bibliographic record
Abstract
Introduction: Cheyne-Stokes breathing (CSB) is thought to be of central rather than of obstructive origin. Snoring, hypopnoea, obstructive apnoea, and respiratory arousal, traditional metrics of obstruction, are absent in nocturnal CSB. Inspiratory flow limitation (IFL), a more recent metric of obstruction, has not been reported in nocturnal CSB. Aim: To confirm anecdotally observed IFL and so obstruction in CSB. Methods: Of 66 774 sleep polygraphs submitted for diagnostic interpretation (www.sagatech.ca) 30 (0.045%) technically acceptable tests were reported to have CSB by two physician interpreters. A third physician interpreter (NS) did not distinguish CSB from other central pattern sleep disordered breathing so had central pattern studies reviewed again for CSB. 4 of these 100 recalled studies showed CSB. The authors then reviewed these 34 studies to confirm CSB. Patented breath-by-breath automated IFL scoring of the flow signal was performed. Fleiss9 kappa was calculated for observer agreement. Results: Only 10 of 30 historic plus the 4 further records records (14 of 66 774, < 1%) had true CSB with oscillating crescendo-decrescendo flow amplitude, alternating apnoea on flow signal, absent snoring, and sinusoidal oximetry. All 14 of these true positive CSB studies had oscillating crescendo-decrescendo IFL during hyperpnoea. Fleiss9 kappa for the true positive diagnosis of CSB was 1.00 amongst the three authors. Conclusions: CSB is very rare in ambulatory sleep polygraphy. Oscillating IFL is ubiquitous in true CSB hyperpnoea suggesting mixed central and obstructive origins. CSB detection could be improved by applying both strict standard definitions and automated IFL analysis.
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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 | 0.001 | 0.005 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| 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) | 0.002 | 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".