Morbidity and mortality associated with preclinical tracheostomy models.

OBJECTIVES/HYPOTHESIS: A secure airway is critical to study obstructive disorders of the larynx and trachea in preclinical models. Tracheostomy has been described in rabbits, swine, canines, and other mammals using tracheostomy tubes or permanent stomas. No studies specifically evaluated morbidity and mortality associated with these models, and existing studies using tracheostomy make little mention of tracheostomy-related complications. We assessed the management, complications, and mortality associated with tracheostomy in a rabbit model that has recently gained significant attention.

STUDY DESIGN: In vivo.

METHODS: Twenty-two female rabbits underwent tubeless tracheotomy. Rabbits were monitored hourly for the first 8 hours, with progressively increasing intervals between evaluations up to 7 days. A suctioning and tracheal moisture protocol was employed, and animals with signs of crusting or impending airway compromise underwent therapeutic bronchoscopy.

RESULTS: Nine of 22 (41%) rabbits succumbed to tracheostomy-related complications, ranging from 1 to 7 days after tracheotomy. The experiment consisted of two study groups. The preliminary group of 10 rabbits studied over a 4-day period had 40% mortality. After implementing modified preventive therapy guidelines and a new humidification system, the second group of 12 rabbits studied over a 7-day period had 42% mortality. Average time to unrecoverable complication was 2.2 days (median = 2 days). Cause of death was airway obstruction in four animals and respiratory depression in three animals, and two animals were found unresponsive.

CONCLUSION: Tracheostomy in preclinical rabbit models should be temporally limited, and investigators should anticipate tracheostomy-related complications during study design.

LEVEL OF EVIDENCE: NA. Laryngoscope, 128:E68-E71, 2018.