Lung mechanics in obesity and changes with bariatric surgery: The role of airway smooth muscle tone and airway unloading
Bibliographic record
Abstract
Introduction: Obesity reduces airway caliber by unloading the airway wall often resulting in sleep disordered breathing and asthma-like symptoms. These respiratory conditions often improve following weight loss however the mechanisms are not well understood. Methods: We investigated the role of unloading the airway smooth muscle in 8 obese patients and the change in lung mechanics before and 5 weeks after bariatric surgery by measuring respiratory system resistance ( Rrs ) and reactance ( Xrs ) with the forced oscillation technique (TremoFlo TM ) at 6, 11, 19 Hz in the upright and supine position, and pre- and post-bronchodilation (BD, 200 mcg salbutamol). Results and Discussion: Before surgery and pre-BD, the change from upright to supine increased average Rrs from 3.61±0.6 to 4.19±0.54 cm H 2 0 l -1 s -1 (p Xrs decreased at each frequency (by 1.01±0.28 cm H 2 0 l -1 s -1 at 11 Hz). These differences disappeared following a mean weight loss of 11.3±0.7 kg after surgery. Although posture had no effect on Rrs post-BD, it caused a decrease in Xrs both before and after surgery. Similarly, BD in the upright posture caused pre-surgery Xrs at 6 Hz to increase by 0.8±0.33 cm H 2 0 l -1 s -1 but no effect post-surgery while BD in the supine posture decreased average Rrs by 20±9% before surgery but not after. Conclusion: The reductions in supine induced changes in Rrs and Xrs following surgery suggest a decrease in unloading of the airway wall from upright to supine due to weight loss. This is consistent with the loss of the supine BD effect on Rrs and Xrs post-surgery which also implies an increase in peripheral airway baseline diameter and improved lung function.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 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 | 0.001 |
| 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".