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Objective—To evaluate bronchial morphology endoscopically in rabbits and develop a valid nomenclature for the endobronchial branching pattern.

Animals—10 mature New Zealand White rabbits.

Procedures—Flexible bronchoscopy was performed in rabbits anesthetized with isoflurane via nasal mask. Airways were systematically evaluated from the larynx to the terminal branches accessible with a 2.5-mm–outer diameter flexible endoscope. Airway branching patterns were identified and assessed for variation among subjects.

Results—Airways of all rabbits were readily examined with the 2.5-mm flexible endoscope. Laryngeal structure and function were normal in each rabbit, and airway branching patterns in all rabbits evaluated were identical. At the carina, branching into left and right principal bronchi was evident. The left principal bronchus divided immediately into the left cranial and left caudal lobar bronchi. The left cranial lobe bronchus further divided into dorsal and ventral segmental bronchi. The left caudal lobe bronchus gave rise to branches originating dorsally, ventrally, and medially before continuing caudally. The right principal bronchus divided into the right cranial, right middle, and accessory lobar bronchi and continued distally as the right caudal lobar bronchus. The right cranial lobe bronchus also divided into dorsal and ventral segmental bronchi, and the right caudal lobe bronchus had branches that originated dorsally, ventrally, and medially.

Conclusions and Clinical Relevance—Definition of a standard nomenclature for airway branching in rabbits will allow precise localization of disease in clinical cases and accurate collection of airway samples in clinical and scientific evaluations.

Full access
in American Journal of Veterinary Research


Objective—To determine the effects of body position on lung and air-sac volumes in anesthetized and spontaneously breathing red-tailed hawks (Buteo jamaicensis).

Animals—6 adult red-tailed hawks (sex unknown).

Procedures—A crossover study design was used for quantitative estimation of lung and air-sac volumes in anesthetized hawks in 3 body positions: dorsal, right lateral, and sternal recumbency. Lung volume, lung density, and air-sac volume were calculated from helical computed tomographic (CT) images by use of software designed for volumetric analysis of CT data. Effects of body position were compared by use of repeated-measures ANOVA and a paired Student t test.

Results—Results for all pairs of body positions were significantly different from each other. Mean ± SD lung density was lowest when hawks were in sternal recumbency (–677 ± 28 CT units), followed by right lateral (–647 ± 23 CT units) and dorsal (–630 ± 19 CT units) recumbency. Mean lung volume was largest in sternal recumbency (28.6 ± 1.5 mL), followed by right lateral (27.6 ± 1.7 mL) and dorsal (27.0 ± 1.5 mL) recumbency. Mean partial air-sac volume was largest in sternal recumbency (27.0 ± 19.3 mL), followed by right lateral (21.9 ± 16.1 mL) and dorsal (19.3 ± 16.9 mL) recumbency.

Conclusions and Clinical Relevance—In anesthetized red-tailed hawks, positioning in sternal recumbency resulted in the greatest lung and air-sac volumes and lowest lung density, compared with positioning in right lateral and dorsal recumbency. Additional studies are necessary to determine the physiologic effects of body position on the avian respiratory system.

Full access
in American Journal of Veterinary Research