Evaluation of upper airway patency during Cheyne–Stokes breathing in heart failure patients
Bibliographic record
Abstract
Little is known about the changes in upper airway calibre in Cheyne-Stokes respiration (CSR) during sleep in patients with congestive heart failure. This study aimed to test the hypothesis that upper airway closure occurs during central CSR events, by assessing upper airway calibre during sleep using the forced oscillation technique (FOT). Nine males with compensated heart failure (left ventricular ejection fraction mean ± sem 27.9 ± 5.1%) and predominant central CSR (apnoea/hypopnoea index 43.9 ± 4.2 events · h(-1)) were studied during overnight polysomnography, which included pneumotachography, inductance plethysmography or oesophageal pressure and FOT-derived impedance signal (|Z|). Baseline |Z| values during stable breathing in stage 2 sleep were 11.0 ± 1.3 cmH(2)O · s · L(-1). Mean |Z| increased to 31.9 ± 6.7 cmH(2)O · s · L(-1) during obstructive apnoeas (7% of events, n = 46). Increases in |Z| consistent with upper airway narrowing (more than two-fold baseline) were common during central apnoeas (50 ± 12% of events) occurring in the middle or end of apnoeas and occurred during some central hypopnoeas (16 ± 10% of events), typically in the expiratory phase. These findings indicate that in heart failure patients, reductions in upper airway calibre are common during CSR apnoeas, and may also occur during central hypopnoeas.
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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 | 0.000 |
| 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) | 0.001 | 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".