Improvement in upright and supine lung mechanics with bariatric surgery affects bronchodilator responsiveness and sleep quality
Bibliographic record
Abstract
Obesity and weight loss have complex effects on respiratory physiology, but these have been insufficiently studied, particularly at early time points following weight loss surgery and in the supine position. We evaluated 15 female participants with severe obesity before and 5 wk and 6 mo after bariatric surgery using the Pittsburgh Sleep Quality Index (PSQI), spirometry, plethysmography, and oscillometry to measure respiratory system mechanics. Oscillometry and spirometry were conducted in the upright and supine position and before and after bronchodilation with 200 µg of salbutamol. At 5 wk postsurgery, weight loss was 11.9 kg (SD 2.7) with no effect on spirometric outcomes and a slight effect on oscillometric outcomes. However, at 6 mo weight loss was 21.4 kg (SD 7.1) with a 14.1% (SD 6.1) and 17.8 (5.4)% reduction in upright and supine respiratory system resistance (Rrs),6, respectively. Respiratory system elastance also decreased by 25.7% (SD 9.4) and 20.2 (SD 7.2)% in the upright and supine positions. No changes were observed in spirometry, but sleep quality improved from PSQI of 8.4 (SD 3.5) to 4.1 (SD 2.9). Bronchodilator responsiveness was low at baseline but increased significantly after surgery, and this response was comparable to the improvement in Rrs produced by weight loss. Modeling the impedance spectra with a two-compartment model demonstrated that improvements in lung mechanics with weight loss begin in the upper or central compartment of the lungs and progress to include the peripheral compartment. Respiratory mechanics are impaired in individuals with severe obesity and is associated with poor sleep quality, but these improved substantially with weight loss. Our data provide new evidence that individuals with severe obesity may have poor sleep quality because of abnormal respiratory mechanics that weight loss improves. NEW & NOTEWORTHY This is the first study to quantify the degree of weight loss-induced improvements in respiratory system mechanics in both upright and supine positions, and its association with bronchodilator responsiveness and sleep quality at multiple time points. Weight loss induced large improvements in upright and supine respiratory system mechanics with corresponding improvements in bronchodilator responsiveness and sleep quality. Using mathematical modeling, we demonstrate that these improvements begin in the central airways and progress to include the lung periphery.
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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 | 0.000 |
| 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".