Abstract
Pulmonary function testing (PFT) is a noninvasive testing methodology that provides objective, quantifiable measures of lung function and diseases that affect the heart and lungs. PFT is a key component of respiratory medicine in humans with a wide array of indications for testing and screening.1 Since the 1940s the respiratory parameters of cetaceans have been measured,2-10 but the extreme flow rates achieved, large exchange volumes, short respiratory cycle, and animal logistics make accurate measurement of these parameters challenging. Utilizing a custom-built system of our own design, we have been able to perform pulmonary function testing in a variety of species. By concurrent measurement of expired gas composition and esophageal pressure, this method allows breath-by-breath assessment of O2 consumption and CO2 production rates and dynamic lung compliance. To date, we have collected data on healthy odontocetes in public display facilities, on stranded animals in rehabilitation, and on wild bottlenose dolphins during capture-release health assessment. Comparative data have also been collected on animals with chronic respiratory disease. PFT performed before and after treatment for respiratory tract disease can provide an objective measure of response to therapy for medical management of disease and for interventional procedures. In addition to the clinical applications of PFT, the research applications with cetaceans have just begun to be explored. By collaborating with curatorial, animal care, and training staff at public display facilities we have measured respiratory parameters in unrestrained, relaxed cetaceans. There is a paucity of information about normal respiratory physiology in cetaceans, even less of which is experimentally derived. Understanding normal respiratory physiology is a key component of learning more about diving physiology, such as how pressure affects gas kinetics, how marine mammals manage gases while diving, and at what point respiratory physiology may limit diving performance. We have also collaborated on a wide variety of projects including studies to evaluate the metabolic cost of swimming underwater and additional metabolic costs associated with increasing the hydrodynamic drag when attaching external data loggers, and investigating potential correlations between recorded breath sounds and various respiratory and metabolic parameters in free-ranging cetaceans. Multidisciplinary collaboration and technological advances have made PFT more viable and accurate for use in cetaceans and we have only just begun to explore possible applications.
Acknowledgements
The authors would like to thank the wonderful staff and trainers at Dolphin Quest, Oahu; the Vancouver Aquarium; Dolphinaris; Six Flags, Vallejo; and Sea World. We would like to acknowledge Trevor Austin of PaxArms, Ltd., NZ for his contributions to the modification of the prototype pneumotachometer. Funding for this project was provided by the Office of Naval Research (ONR YIP Award #514 N000141410563). SHL received funding from Beth Israel Anesthesia foundation. Dolphin Quest 515 provided in-kind support of animals, crew and access to resources. Field work in Sarasota Bay, Florida, in 2014 was supported by Dolphin Quest and the Office of Naval Research, carried out by the staff, students, trained volunteers and collaborators of the Sarasota Dolphin Research Program, and performed under NMFS Scientific Research Permit No. 15543 and Mote Marine Lab IACUC approvals.
* Presenting author
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