Figure 4. Representative sections from trachea of sheep intubated with the new ETT or the standard ETT for 1 or 3 days; hematoxylin and eosin stain. Original magnification x160. (A) One-day intubation, new ETT. The epithelium is mostly intact. Tissue reaction is minimal. (B) One-day intubation, standard ETT. Widespread epithelial erosion is present with minimal tissue reaction. (C) Three-day intubation, new ETT. Epithelium is intact. There is no submucosal hemorrhage or edema. (D) Three-day intubation, standard ETT. Area in contact with the cuff shows wide epithelial erosion. Note severe submucosal hemorrhage.