75.3 Saturday, Jan. 5 A Comparative Study of Cetacean Respiratory Mechanics: Implications for diving and health assessment PISCITELLI, M.A.*; LILLIE, M.A.; RAVERTY, S.A.; SHADWICK, R.E.; Univ. of British Columbia, Vancouver; Univ. of British Columbia, Vancouver; British Columbia Ministry of Agriculture, Food, and Fisheries; Univ. of British Columbia, Vancouver email@example.com
The cetacean respiratory system has undergone diverse and highly specialized anatomical and mechanical adaptations to accommodate a strictly aquatic lifestyle. In contrast to terrestrial mammals, the cetacean respiratory system is adapted to operate on an inspiratory breath-hold. During a dive, air in the lungs is carefully managed to perform multiple, simultaneous functions, including gas exchange, buoyancy control, echolocation, vocalization and foraging. Because their respiratory system carries out multiple roles, respiratory diseases have the potential to greatly impact a cetacean’s ability to thrive in the wild. Cryptococcus gatti , an endemic fungus to the Pacific Northwest has been the source of mortality in human, terrestrial and cetacean cases, and is a focus of diseased cases in this study. Excised lungs from 8 cetacean families were collected during necropsy. A multi-faceted approach was utilized to examine structural, biomechanical and pathological differences across species. Each lung was imaged in three inflated states using computed tomography followed by static pulmonary mechanics to generate pressure-volume curves. Across families, mass-specific total lung capacity (TLC) decreased with increased diving ability, and opening airway pressures increased with smaller alveolar diameters. Severe infections in diseased lungs decreased mass-specific TLC by up to 93%, increased lung mass four-fold, and decreased compliance. In conclusion, pulmonary mechanics is a useful tool in both understanding the normal physiology of diving mammals and in assessing the pathophysiology of stranded marine mammals.