Effect of acute lung volume reduction surgery on lung mechanics and maximal flow in a canine model of upper lobe emphysema
Notice bibliographique
Résumé
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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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,001 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».