October 11, 2011
Thoracic compression is presented as technically easy to use, rapid and painless by proponents. The advantages of thoracic compression are that it requires no equipment or materials and allows the researcher to collect specimens with undamaged skin and potentially intact bones; tissues or fluid samples that are potentially unaltered; and/or intact archival samples of wildlife for morphologic and other studies.
For example: The Association of Avian Veterinarians states that thoracic compression is "akin to suffocation of mammals" and "cannot be considered humane".1 Individual veterinarians have expressed similar positions based on the belief that thoracic compression does not stop the heart.2 And, ethicist Bernard Rollins (2009) states that "suffocating birds using thoracic compression (crushing the chest)" is currently "unthinkable" as a method of euthanasia.3
Asphyxia versus cardiac arrest--Winker (2000) asserts that thoracic compression "… instantly stops the heart and lungs, and must cause blood pressure to skyrocket. For small birds, it seems that unconsciousness occurs instantly; death follows very quickly."4 Should this assertion that death results from cessation of cardiac function be empirically substantiated, this may justify consideration of the technique as a means of euthanasia.
Larger mammal species and human accident victims subject to thoracic compression do not seem to experience heart failure as their primary cause of death.5,6 However the heart and lung anatomy of small mammal and especially birds differ significantly from these species, and their cause of death when subject to this technique has not been objectively determined. Data relating to the onset of unconsciousness would also be of value.
Large versus small animals and field conditions-- It is generally acknowledged that thoracic compression is not appropriate for large animals (including large birds).7 While field conditions can be exceptionally challenging, there is no clear basis for the argument that small animals have a lesser capacity to suffer pain and distress, or that acquisition and portage difficulties relating to equipment and supplies required for euthanasia of small animals are prohibitively greater than those already encountered during the study of larger species.
Technique—In conjunction with the collection of validating data, this technique would benefit from precise characterization and standardization.
Over the last decades, decision making processes have moved towards a precautionary approach of avoiding the use of techniques where 1) the nearest equivalent practice would cause suffering in humans and/or 2) the technique might cause suffering in the target species and there is no scientific evidence to the contrary.15,16,17 To date, there is a lack of research into the merits and demerits of thoracic compression.
REFERENCES1 Bennett RA. Association disagrees with euthanasia method for avian species. J Am Vet Med Assoc 2001;218(8):1262.2 Ludder J. Another reader opposing thoracic compression for avian euthanasia. J Am Vet Med Assoc 2001;218(11):1718-1722.3 Rollin BE. Ethics and euthanasia. 2009;50:1081-1086.4 Winker K. Obtaining, preserving, and preparing bird specimens. Journal of Field Ornithology 2000;71(2):250-297.5 Rosato RM FAU, Shapiro MJ FAU, Keegan MJ FAU, et al. Cardiac injury complicating traumatic asphyxia.(0022-5282 (Print)).6 Ildstad ST FAU, Tollerud DJ FAU, Weiss RG FAU, et al. Cardiac contusion in pediatric patients with blunt thoracic trauma. J Pediatr Surg 1990;25(0022-3468 (Print)):287-289.7 Wingfield WE, Palmer SB Veterinary Disaster Response 2009 John Wiley and Sons: Hoboken, New Jersey8 Parker, W.T., L.I. Muller, R.R. Gerhardt, D.P. O'Rourke, and E.C. Ramsay. 2008. Field use of isoflurane for safe squirrel and woodrat anesthesia. Journal of Wildlife Management 72:1262–1266.9 Addendum #1 to 2007 Guidelines of the American Society of Mammalogists on the use of wild mammals in research—approved June 2008 . Available at: http://www.mammalsociety.org/uploads/committee_files/Addendum%201.pdf. Accessed Jul 28, 2010.10 The Association of Avian Veterinarians Website. Accessed July 25th 2010: http://www.aav.org/association/?content=euthanasia11 Canadian Council on Animal Care (CCAC) (2008). Species-specific recommendations on: birds. Ottawa ON: CCAC.12 Fair J, Paul E, Jones J. The ornithilogical council: Providing Scientific Information about Birds Guidelines to the Use of Wild Birds in Research. 2010. Accessed August 30, 2011: http://www.nmnh.si.edu/BIRDNET/documents/guidlines/Guidelines_August2010.pdf13 Minimum standards for wildlife rehabilitation. Available at: http://www.nwrawildlife.org/sites/default/files/MinimumStandards3rdEdition.pdf. Accessed Jul 28, 2010.14 Orosz S. Birds. In: Guidelines for Euthanasia of Nondomestic Animals. American Association of Zoo Veterinarians.2006; 46-49.15 Institute of Laboratory Animal Resources (U.S.). Guide for the Care and Use of Laboratory Animals. Washington: National Academy Press; 199616 Croney CC, Millman ST. The ethical and behavioral bases for farm animal welfare legislation. J Anim Sci 2007;85(2):556-565.17 Criado A. Recognition and Alleviation of Pain in Laboratory Animals. Lab Anim 2010;44(4):380.