Experimental Induction of Squamous Metaplasia in the Dog Trachea with Cuffed Endotracheal Tubes

Abstract

Clinical reports cite the development of squamous metaplasia in tracheas following tracheostomy, laryngectomy, and cuffed intubation. The purpose of this study was (1) to develop an experimental model using the dog trachea and study the effects of prolonged cuffed intubation and (2) to determine whether squamous metaplasia is produced by prolonged contact of the endotracheal cuff with the tracheal mucosa. Modifications of widely used high-volume, low-pressure 8-mm endotracheal tubes were made with the distal portion of the tube, its cuff, and the inflating catheter attached. This model formed an implantable cuffed tube approximately 8 cm in length. The dogs remained intubated for 14 days, at which time they were killed; seven animals were available for histologic study. Varying degrees of squamous metaplasia were produced in all animals.

Tracheal necrosis following tracheal intubation in a dog

“…Tracheal rupture has also been reported in cats (Hardie and others 1999, Mitchell and others 2000, Kastner and others 2004) and tracheal damage and necrosis has been reported in horses (Holland and others 1986, Touzot‐Jourde and others 2002) following tracheal intubation. Dogs have been used as models for subglottic stenosis (Marshak and others 1982, Supance and others 1982) and the induction of squamous metaplasia (Severson and others 1982) following prolonged tracheal intubation. This case report describes a case of tracheal necrosis following endotracheal intubation in a dog.…”

Radioisotope Measurement of the Velocity of Tracheal Mucus

“…After prolonged endotracheal intubation, squamous metaplasia of the tracheal mucosa at the cuff site has been found to occur in humans' and has recently been experimentally induced in a canine model. 2 To study the effect of the squamous metaplasia on the velocity of tracheal mucus, an experimental model utilizing a radioisotope scanning technique has been developed. The experimental model is the subject of this article.…”