title: The effects of tracheal tube tip design and tube thickness on laryngeal pass ability during oral tube exchange with an introducer.
abstract: We compared the ease of passage through the glottis of two different tubes and two different sizes of tracheal tube exchanger (TE) during introducer-guided tracheal intubation. One tube was a polyvinyl chloride tube with a standard bevel, and the other was a newly designed tube with a hemispherical bevel. The outer diameters (OD) of the two TEs were 2.5 and 5.0 mm. After the standard induction of anesthesia, followed by vecuronium-induced paralysis, a TE was inserted into the trachea with a direct laryngoscope. By using the introducer as a guide, the tracheal tube was inserted into the trachea. The difficulty in passing the tube was assessed by a blinded observer and graded with a four-point scale. The newly designed tube was inserted more smoothly than was the conventional tube when the 2.5-mm-OD TE was used (P < 0.01). In situations such as those occurring after one-lung anesthesia, when use of a thicker TE is not applicable, this newly designed taper-tipped tube may be considered as an adjunct to oral tracheal tube exchange, using a thinner (smaller-OD) TE as the guide for tracheal intubation.
  
  
  CONCLUSIONS
  In situations such as after one-lung anesthesia, when use of a thicker tube exchanger (TE) is not applicable, a newly designed taper-tipped tube with the leading edge in the midline may be considered as an adjunct to an oral tracheal tube exchange, using a thinner TE as the guide for tracheal intubation.
authors.affiliation: Department of Anesthesiology and Intensive Care, Hamamatsu University School of Medicine, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Makino
authors.forename: Takasumi
authors.initials: T
authors.lastname: Katoh
authors.forename: Syunji
authors.initials: S
authors.lastname: Kobayashi
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Bito
authors.forename: Shigehito
authors.initials: S
authors.lastname: Sato
mesh_terms: D000769:Anesthesia, Inhalation / Q000295:instrumentation*; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal / Q000295:instrumentation* / Q000379:methods; D007828:Laryngoscopy; D007830:Larynx / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D011143:Polyvinyl Chloride
chemical_list: D011143:Polyvinyl Chloride