The Effect of Prone Position-induced Lung Recruitment is Independent From Its Effect on Perfusion and Gas Exchange: A Secondary Computed Tomography Analysis of a Controlled Circulatory Death Donor Model
Notice bibliographique
Résumé
Abstract RATIONALE: Prone position (PP) is recommended in patients with moderate-severe acute respiratory distress syndrome, as it improves oxygenation, decreases alveolar overdistension, improves lung recruitment, and reduces mortality. However, it has not been conclusively demonstrated whether the beneficial effect of PP-induced lung recruitment is independent from its effect on perfusion and gas-exchange. In an animal model of organ donation after controlled cardiac death (DCD) maintained non-ventilated and non-perfused for 3 hours of warm ischemic time (WIT), our group demonstrated that, after reperfusion in the ex-vivo lung perfusion platform in standard position, gas exchange, compliance and vascular resistance were better in lungs from pigs maintained in PP during WIT compared to those kept supine1.Whether these results depend on changes in alveolar recruitment in this model, which allows to separate the effect of PP on perfusion and gas-exchange from that on alveolar recruitment, has not been studied. METHODS: We analyzed the computed tomography scans (CT) performed in our previous DCD model investigation to compare the lung volume distribution overtime in supine and PP.In the original experiment, ten Yorkshire DCD pigs were randomly assigned to prone (n=5) or supine (n=5) position during 3 hours of WIT. After being ventilated in the assigned position for five minutes, the airway was clamped at peak pressure of 25 cmH2O to maintain lung inflation during WIT. C-arm cone-beam CT (Siemens Healthcare) was performed at the beginning (T0) and the end of WIT (T3) in 3 pigs in each group and analysed with the Mimics Medical 19 software (Materialise). Lung below the diaphragm were manually contoured and four lung compartments (non-aerated, poorly aerated, normally aerated and hyperinflated) were identified based on the distribution of Hounsfield Unit, using conventional thresholds. Lung tissue weight was expressed as percentage of total lung volume. RESULTS: At T0, in the PP the medians of normally aerated tissue and poorly aerated tissue were 93% (99-93) and 5% (4-7), compared to 65% (62-66) and 29% (28-33) in supine position (p<0.01). At T3, in the PP group the normally aerated and the poorly aerated tissue were 92% (90-92) and 6% (5-8), respectively, compared to 60% (58-60) and 36% (35-38) in the supine group (p<0.01-Figure1). DISCUSSION: PP resulted in higher alveolar recruitment during WIT with consequent better lung physiologic performance after reperfusion, indicating that the benefit of PP-induced alveolar recruitment is independent from its effect on perfusion and gas exchange.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
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 | 0,001 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,001 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,001 |
| Bibliométrie | 0,001 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,001 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,001 |
| Intégrité de la recherche | 0,000 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,003 | 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 ».