Abstract
Post-intubation tracheal obstruction may be more common in zoo birds than previously recognized.1-4 A review of medical records from two institutions over a 13-year period revealed 22 cases, with an incidence of 2.5–5%. For both institutions, Ciconiiformes, Columbiformes, Galliformes, and Gruiformes more commonly developed this complication, though Anseriformes and Passeriformes were also affected at one institution. Birds most commonly presented in acute respiratory distress, though three cases only displayed respiratory distress when handled or stressed. Diagnosis was commonly made by observing a soft-tissue density within the trachea radiographically and/or by tracheoscopy.
Five birds died acutely prior to treatment. Seventeen were treated: nine medically (three survived) and eight surgically by tracheal resection (four survived). Medical treatments included tracheal suction and manual removal of intralumenal material, intratracheal topical treatments, and nebulization. The three surviving medical cases were less severely affected, having only a mucoid plug that was not adhered to the trachea. Four surgical cases failed due to re-stricture/obstruction. Factors leading to the failures are unclear as all procedures were performed similarly and only one case was anastomosed under tension.
Based on histologic review, the underlying cause is suspected to be trauma from the end of the endotracheal tube, or possibly from forced air flow, leading to mucosal damage, reactive exuberant mucus, and granulation tissue formation. No association with concurrent illnesses, tube type, or tube cleaning/sterilization procedures was observed. Care should be taken when intubating susceptible species.
Acknowledgments
We gratefully thank all the clinical, technical, and animal care staff involved in the individual cases. Special thanks to Susan Feltman and the medical records departments of Disney’s Animal Kingdom for assistance with record review. Thanks to Dr. Stephanie James for initiating and inspiring this review.
Literature Cited
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