Effect of acute lung volume reduction surgery on lung mechanics and maximal flow in a canine model of upper lobe emphysema
Bibliographic record
Abstract
Ourfrle Nol.re rërërence /S8/Vi AVIS: L'auteur a accordé une licence non exctusive permettant à la Bibliothèque et Archives Canada de reproduire, publier, archiver, sauvegarderi conserver, transmettre au public par télécommunication ou par I'tnternet, prêter, distribuer et vendre des thèses partout dans le monde, à des fins commerciales ou autres, sur support microforme, papier, électronique et/ou autres formats.that the degree of lung inflation would not affect the results pre-and post-LVRS.A small pressure sensor was placed into the airway (Pitorstatic tube) under bronchoscopic guidance in order to determine airway lateral (P1u1) and end-on pressure (P.no) as well as the site of flow limitation (termed the choke-point -CP) during forced deflation.In the analysis, V'*, CP site, lung elastic recoil pressure (Pr1), and intrabronchial pressures were measured at 70o/o, 50o/o, and 30%o vital capacity (VC) at each study interval.The flow limitation studies were performed after emphysema was produced and repeated approximately I month later, immediately after acute LVRS was performed in the animals randomized to surgery, or at comparable intervals in the non-LVRS dogs.Papain emphysema was associated with significant increases in TLC, residual volume (RV), and functional residual capacity (FRC) as compared with pre-emphysema measurements.Post-emphysema, the lung pressure-volume curve was shifted upward andto the left as compared to baseline, indicating that the major physiological effect that occurred after papain administration was air trapping.V',* in the emphysema dogs were significantly reduced compared to those found in the non-emphysema dogs at the three lung volumes studied.In the emphysema dogs, CP at the two higher lung volumes were generally found more upstream as compared to the non-emphysema dogs.Cross-sectional area (A*) at the CP were significantly less than corresponding measurements determined in the non-emphysema dogs.Immediately after LVRS was performed, TLC, vC, and IC in the emphysema dogs (n:6) returned to near pre-emphysema values, while TLC, VC, and IC decreased approximately 20o/o in the non-emphysema dogs (n:5).Respiratory compliance was reduced following LVRS in both the emphysema and non-emphysema dogs.Pressure- volume curves obtained after LVRS in both the emphysema and non-emphysema dogs were shifted downward and to the right as compared with the respective pre-surgery curves.Following surgery, Ps¡ at the three fractions of VC increased in both the emphysema and non-emphysema dogs.Vn,'* in the emphysema dogs decreased at the two higher lung volumes as compared with pre-LVRS, while V** was slightly increased at the lowest lung volume.In both the emphysema and non-emphysema dogs, LVRS was associated with a tendency for P¡, and frictional resistance to increase as compared to pre- surgery.In summary, LVRS in the acute postoperative period is associated with a decrease in respiratory compliance and an increase in Pr¡, while Vn,'* did not increase.Postoperatively, these acute effects may lead to difficulty in weaning patients from mechanical ventilation and may contribute to morbidity and mortality.Understanding these complex changes in lung mechanics following LVRS may help to better select patients who would benefit from the surgery.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| 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 | 0.001 | 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".