Novel Approach in the Evaluation of Flap Failure Using near Infrared Spectroscopy and Imaging
Notice bibliographique
Résumé
Methods of tissue viability assessment should be classified into those that measure blood flow and those that monitor tissue metabolism. The problem with measuring blood flow is that it can be misleading due to the phenomenon of arteriovenous shunting. Near infrared (NIR) spectroscopy is capable of identifying certain molecules in the tissues. In this study, using the reverse McFarlane rat skin flap as a model, oxygen delivery to the tissue along the flap was demonstrated in the form of a spectrum. This was achieved by using the differential absorption of oxy- and deoxyhemoglobin between wavelengths of 650 nm and 900 nm. NIR imaging works on a similar principle, but an oxygen saturation image is obtained, with the darkest area indicating the most deoxygenated area of the flap and vice versa. There were two types of studies done. In the chronic study (n=10), NIR spectroscopy was done on the intact skin preoperatively for three days and then after elevation of the flap at various sites for three days. Preoperative measurements showed excellent reproducibility, and postoperative measurements showed progressive deoxygenation toward the distal aspect of the flap. NIR imaging at 1 h after flap elevation showed a zone of demarcation that corresponded with that noted clinically at 72 h. In the acute study (n=3), NIR spectroscopy, imaging and laser Doppler flowmetry were acquired before, immediately following and 1 h after raising the flap, and then measurements were taken after applying a vascular clamp across the base of the flap; reperfusion was evaluated after clamp release. Spectroscopy immediately following flap elevation indicated deoxygenation of the most distant part of the flap. Clamping the base of the flap caused deoxygenation of the whole flap; this was immediately evident on both spectroscopy and imaging. These changes recovered after releasing the clamp in the areas that were expected to survive. Laser Doppler flowmetry results generally correlated well with the NIR spectroscopy and imaging results. However, the method was very sensitive to fine movements during monitoring. The main advantage of NIR monitoring is that it looks directly at oxygen consumption rather than measuring blood flow. In addition, the NIR imaging gives a global picture of the eventual fate of the flap. These properties make these devices much more practical when the flap's well-being is concerned.
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Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| 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 | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 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 tête enseignante, 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 ».