Abstract

Café coronary is a term used to describe accidental asphyxiation resulting from food impaction in the upper aerodigestive tract. Fatal asphyxiation in cetaceans resulting from laryngeal displacement by intended prey impaction has been reported previously.^1-7 The interpretation of fatal asphyxiation requires definitive and compelling evidence from the post-mortem examination, death scene, and/or history, which is often hindered by the carcass condition in stranded cetaceans. Location of a food bolus need not necessarily be the same at necropsy as at the time of death, as foreign material can be dislodged during organ removal.

In humans, virtopsy techniques like post-mortem computed tomography (PMCT) can localize food bolus and visualize the aerodigestive tract in multiple reformatted planes, with small hemorrhages in the laryngeal muscles easily assessable prior to autopsy.^8,9 PMCT can confirm the diagnosis of laryngeal obstruction by food bolus. To the best of our knowledge, the formal literature is devoid of any reference to the applicability of virtopsy in the diagnosis of fatal asphyxiation in stranded cetaceans. This study aimed to evaluate the practicality of virtopsy techniques in stranded cetaceans and compared the findings obtained by conventional necropsy.

Retrospective analysis of stranding cases with food bolus aerodigestive tract obstruction as the defined cause of death were undertaken, with both PMCT and conventional necropsy performed. PMCT was useful in identifying position and direction of the food bolus, orientation of goosebeak, hemorrhage in the adjacent muscle and blubber layers, and distribution and discharge characteristics of the trachea and bronchi. PMCT post-processing techniques including virtual bronchoscopy and gastroscopy allowed planning and assisting in minimally invasive bronchoscopic and gastroscopic interventions during the conventional necropsy.

This study demonstrated virtopsy as a potentially powerful tool, providing non-invasive and objective measurements to supplement the necropsy findings in diagnosis of fatal asphyxiation in stranded cetaceans. PMCT should be considered for cases of suspected asphyxiation, as an initial screening procedure to rapidly produce preliminary information to guide the necropsy examination.

Acknowledgements

The authors would like to thank the Agriculture, Fisheries and Conservation Department of the Hong Kong SAR Government for the support in the virtopsy project. Sincere appreciation is also extended to veterinarians, staff, and volunteers from Ocean Park Hong Kong, Ocean Park Conservation Foundation Hong Kong for paying great effort on the stranding response and necropsy in this project. Special gratitude is owed to technicians from Peace Avenue Veterinary Clinic, City University of Hong Kong for operating the CT units to collect volumetric data in the present study. This project was financially supported by the Marine Ecology Enhancement Fund (Grant number: MEEF2017014/L01). Any opinions, findings, conclusions, or recommendations expressed herein do not necessarily reflect the views of the Marine Ecology Enhancement Fund or the Trustee.

* Presenting author

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