Lapis ISSN 2398-2969

Trachea: stricture

Synonym(s): Tracheal stricture, tracheal stenosis

Contributor(s): Lesa Thompson, Elisabetta Mancinelli

Introduction

  • Cause: mechanical abrasion, inflammation, focal edema, hemorrhage, erosion, ulceration, pressure necrosis with secondary stenosis.
  • Signs: usually arise 2-21 days post-intubation and include inspiratory dyspnea, respiratory wheezing, barking sounds, harsh lung sounds, dark pink to cyanotic (blue) mucous membranes, neck hyperextension associated with increased breathing effort, elbow abduction, nasal flaring, open mouth breathing, abdominal effort.
  • Diagnosis: history of recent endotracheal intubation (ETI), clinical signs, radiography, tracheoscopy, post mortem, histopathology.
  • Treatment: medical treatment usually unrewarding, surgical treatment not reported in rabbits.
  • Prognosis: poor.

Anatomy

  • Rabbits have a small and narrow oropharynx with reduced mandibular excursion, a relatively large and fleshy tongue and a small, steep and ventral laryngeal opening which makes ETI a relatively difficult task.
  • The epiglottis is normally engaged over the soft palate thus preventing access to the trachea via the oral cavity.
  • Hyperextension of the head facilities disengagement and ventral repositioning of the epiglottis allowing intubation.
  • The rabbit trachea courses caudally in a slightly open angle to the thoracic vertebrae and ends at the 4th intercostal space.
  • The rabbit trachea has a rich vascular sinus in the submucosa and mucosa with few glands.
  • Average airway size has been reported for New Zealand White rabbits, with a weight range of 2.3-5.1 kg, at the level of the cricoid cartilage (5.4-5.8 mm) and the 8th tracheal cartilage (4.7-5.9 mm).
  • The dimension of the subglottis is independent of weight, whereas the tracheal size at the 8th intercostal space varies significantly with weight.
  • Severe hyperemia of the trachea is a normal finding, however the deep red color does not involve the dorsal tracheal membrane and stops at the level of the carina.

Risk factors

  • Traumatic/prolonged intubation.
  • Incorrect intubation technique.
  • Use of a cuffed or un-cuffed endotracheal tube (ETT).
  • Infection.
  • Movement of the ETT.
  • Exposure to irritating substances.

Presenting signs

  • Usually arise 2-21 days post-intubation.
  • Inspiratory dyspnea   Dyspnea  .
  • Respiratory wheezing.
  • Barking sounds.
  • Harsh lungs sounds.
  • Mucous membranes are dark pink to cyanotic.
  • Neck hyperextension.
  • Elbow abduction.
  • Nasal flaring.
  • Opened mouth breathing.
  • Abdominal effort.

Acute presentation

  • Sudden onset of respiratory distress in an animal that is otherwise well normally suggests tracheal obstruction.
  • In mammals, dyspnea at rest is noticeable when the luminal compromise is severe and the tracheal diameter is reduced by 85-90%.

Species/breed predisposition

  • One report described the rabbit trachea as rich in vascular supply, suggesting the pressure and ischemia caused by a tracheal tube may hinder tracheal perfusion, contributing to the risk of mucosal damage and stenosis.
  • It is possible that this species may be more susceptible to any type of mucosal irritation. In one laboratory study, simple brushing of the mucosa led to stricture within 14 days with a narrowing of 43%.

Special risks, eg anesthetic

  • High risk anesthetic patients.
  • Ventilator compromise.
  • Complete occlusion of the airway by equipment.

Pathogenesis

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Diagnosis

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Treatment

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Prevention

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Sequelae

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Further Reading

Publications

Refereed papers
  • Recent references fromPubMed.
  • Xusong L et al(2013)Long-term functional reconstruction of segmental tracheal defect by pedicled tissue-engineered trachea in rabbits. Biomaterials34(13), 3336-3344. ISSN: 0142-9612. Website:http://dx.doi.org/10.1016/j.biomaterials.2013.01.060 PubMed.
  • Steehler M K, Hesham H N, Wycherly B J, Burke K M & Malekzadeh S (2011)Induction of tracheal stenosis in a rabbit model -endoscopic versus open technique. Laryngoscope121(3), 509-514PubMed.
  • Crotaz I (2010)Initial feasibility investigation of of the v-gel airway: an anatomically designed supraglottic airway device for use in companion animal veterinary anaesthesia. Vet Anaesthesia Analgesia37(6), 579580PubMed.
  • Nakagishi Y, Morimoto N, Fujita M, Ozeki Y, Maehara T, Kikuchi M & Moromoto Y (2009)Amelioration of airway stenosis in rabbit models by photodynamic therapy with talaporfin sodium (NPe6). Photochem Photobiol85(3), 714-718PubMed.
  • Lennox A M & Capello V (2008)Tracheal intubation in exotic companion mammals. JEPM17(3), 221-227PubMed.
  • Chao-Hsien L, Ming-Jen P & Chien-Liang W (2007)Dexamethasone to prevent postextubation airway obstruction in adults: a prospective, randomized, double-blind, placebo-controlled study. Critical Care11(4), R72. doi: 10.1186/cc5957PubMed.
  • Culp W T N, Weisse C, Cole S G & Solomon J A (2007)Intraluminal tracheal stenting for treatment of tracheal narrowing in three cats. Vet Surg36(2), 107-113PubMed.
  • Grint N J, Sayers I R, Cecchi R, Harley R & Day M J (2006)Postanaesthetic tracheal strictures in three rabbits. Lab Anim40(3), 301-308PubMed.
  • Gubbels S P, Richardson M, Trune D, Bascom D & Wax M (2006)Tracheal reconstruction with porcine small intestine submucosa in a rabbit model. Otolaryngology-Head Neck Surg134(6), 1028-1035PubMed.
  • Phaneuf L R et al(2006)Tracheal injury after endotracheal intubation and anaesthesia in rabbits. J Am Assoc Lab Anim Sci45(6), 67-72PubMed.
  • Dodge-Khatami A et al(2003)Topical vascular endothelial growth factor in rabbit tracheal surgery: comparative effect on healing using various reconstruction materials and intraluminal stents. European J Cardiothoracic Surg23(1), 6-14PubMed.
  • Loewen M S & Walner D L (2001)Dimensions of rabbit subglottis and trachea. Lab Anim35(3), 253-256PubMed.
  • Loewen M S, Walner D L & Caldarelli D D (2001)Improved airway healing using transforming growth factor beta-3 in a rabbit model. Wound Rep Regen9(1), 44-49PubMed.
  • Kil H K, Alberts M K, Liggitt H D & Bishop M J (1997)Dexamethasone treatment does not ameliorate subglottic ischemic injury in rabbits. Chest111(5), 1356-1360.
  • Nordin U & Lindholm C E (1977)The vessels of the rabbit trachea and ischemia caused by cuff pressure. Archives of Otorhinolaryngology215(1), 11-24PubMed.
  • Nordin U, Lindholm C E & Wolgast M (1977)Blood flow in the rabbit tracheal mucosa under normal conditions and under the influence of tracheal intubation. Acta Anaesthesiologica Scandinavia21(2), 81-94PubMed.
  • Conrardy P A, Goodman L R, Lainge F & Singer M M (1976)Alteration of endotracheal tube position. Flexion and extension of the neck. Crit Care Med4(1), 7-12PubMed.
  • Coon R A, Jones R A, Jenkins L J Jr & Siegel J (1970)Animal inhalation studies on ammonia, ethylene glycol, formaldehyde, dimethylamine, and ethanol. Toxicol Appl Pharmacol16(3), 646-655PubMed.

Other sources of information

  • Mancinelli E & Eatwell K (2013)Tracheal Stricture after Laparoscopic Ovariectomy in Two Domestic Rabbits.In: Proc 18th Int Vet Emerg & Crit Care Symposium. pp 190.
  • Eatwell K (2012)Use of a Supraglottic Airway Device to Maintain Gaseous Anaesthesia in Rabbits ( Oryctolagus cuniculus).In: Proc 18th Int Vet Emerg & Crit Care Symposium. pp 737.
  • Vella D & Donnelly T M (2012)Basic Anatomy, Physiology and Husbandry.In: Ferrets, Rabbits and Rodents Clinical Medicine and Surgery. Eds: Quesenberry K E & Carpenter J W. 3rd edn. Elsevier. pp 157-173.


ADDED