NEW ULTRATHIN-WALLED ENDOTRACHEAL-TUBE WITH A NOVEL LARYNGEAL SEAL DESIGN - LONG-TERM EVALUATION IN SHEEP

Background: A new endotracheal tube (ETT) was fabricated and tested in sheep, It had no tracheal cuff; airway seal was achieved at the level of the glottis through a no-pressure seal made of ''gills''; the lary ngeal portion was oval-shaped; and the wall thickness was reduced to 0 .2 mm. Methods: Sheep were tracheally intubated either with a standard tube or with the new tube, and their lungs were mechanically ventilat ed for 1 or 3 days. Air leak was recorded at different peak inspirator y pressures (PIPs). Liquid seepage into the trachea was assessed using an indicator dye. Tracheolaryngeal lesions were scored grossly and hi stologically. Results: There was no air leak up to 40 cmH(2)O of PIP, La either group, in short- and long-term studies. Methylene blue leake d across the cuff in two sheep with standard ETTs. No dye leaked acros s the gills with the new ETTs. In the new ETT group, the trachea appea red better preserved, grossly and histologically, than in the standard ETT group at both 1 and 3 days (P < 0.05). At day 1, the larynx and v ocal cords appeared grossly less injured in the new ETT group (P < 0.0 5), whereas there was no difference at day 3. Histology did not show s ignificant difference on vocal cords, epiglottis, and larynx between t he two groups at any time. Conclusions: The novel, no-pressure seal de sign of the new ETT is highly effective in preventing air leak and asp iration. It causes no significant tracheal injury.