protocol review
Response Consider the logistics
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© 2015 Nature America, Inc. All rights reserved.
Laura Gallaugher, DVM, DACLAM & Laurie Goodchild, DVM
Mann does present a valid concern regarding the method of anesthesia induction. Great Eastern University’s institutional policy requiring that mice stay in their home cages during the euthanasia process might be based on the 2013 AVMA Guidelines for the Euthanasia of Animals. This document states that euthanasia should be carried out in familiar surroundings to help reduce stress1. Both the Public Health Service Policy on Humane Care and Use of Laboratory Animals and the Guide for the Care and Use of Laboratory Animals state that the euthanasia of laboratory animals must be done in accordance with the AVMA Guidelines for the Euthanasia of Animals2,3. These policies do not reference specific guidelines for the anesthesia of animals, but why should the animals be treated differently if the only difference in the procedure is whether or not the anesthetic event is terminal? Anesthesia in mice is often induced in a separate chamber, a new environment that presents unfamiliar substrates and odors and is potentially stressful. The IACUC could respond by establishing a policy that mice should be anesthetized in their home cages. There are several factors that the IACUC should consider before doing so. First, if the rodent to be anesthetized is housed with other rodents, then those animals would need to be moved, potentially causing unnecessary stress to those animals. Second, the animal’s home cage typically contains bedding. During induction, the animal may inhale the bedding, leading to an upper airway obstruction. Anesthesia chambers are devoid of objects that could cause an obstruction. Third, animal housing cages do not have adaptors for anesthetic machines, and most institutions do not have anesthesia chambers large enough to accommodate a mouse’s home cage. Logistical solutions to this would have to be explored to make this a viable option. Last, the odor of anesthetic gas itself is aversive and distressful, which might cause some animals to become anxious during induction1. Unfortunately, regardless of the environment, this stress cannot be avoided. 258 Volume 44, No. 7 | JULY 2015
A compromise that might help to reduce stress during anesthesia induction would be to place some familiar nesting material or bedding from the home cage into the chamber along with the rodent. A pilot study could address whether this small change makes a difference! 1. American Veterinary Medical Association. AVMA Guidelines for the Euthanasia of Animals: 2013 Edition (American Veterinary Medical Association, Schaumburg, IL, 2013). 2. Public Health Service. Policy on Humane Care and Use of Laboratory Animals (US Department of Health and Human Services, Washington, DC, 1986; amended 2002). 3. Institution for Laboratory Animal Research. Guide for the Care and Use of Laboratory Animals 8th edn. (National Academies Press, Washington, DC, 2011). Gallaugher is Training and Compliance Specialist and Goodchild is Clinical Veterinarian at Nationwide Children’s Hospital, Columbus, OH.
Response A valid concern Jane J. Na, DVM & Howard G. Rush, DVM, MS, DACLAM
It is appropriate for Mann to consider minimization of animal distress while reviewing this protocol, and she has a valid concern. Because Mann has never had to consider administration of an inhalant agent for anesthetic purposes, it should be explained that there would be a risk for accidental inhalation of material within the home cage that might lodge in the airway1 and potentially complicate further delivery of anesthetic, interfere with the research or adversely affect the animal during and after anesthetic recovery. From our experience, aspiration of foreign material is not common during rodent anesthesia, but introducing the animal into a clean anesthetic chamber can reduce the chance of this complication. Although there is evidence that handling and placement of a rodent into a separate chamber for induction of anesthesia is distressful2, it offers the potential benefit of preventing more distressful events or physical harm from occurring. The current AVMA Guidelines for the Euthanasia of Animals3 (AVMA Guidelines) focus on minimizing stress and m aintaining
animal comfort throughout euthanasia. Because handling a rodent elicits physiologic and behavioral changes that indicate distress2, the AVMA Guidelines recommend keeping a rodent where it is most comfortable prior to administration of inhalant agents for euthanasia3. Studies have evaluated the many factors that contribute to distress associated with the administration of inhalant agents, but the experimental design and methods used are highly variable. Because of this, there is no consensus regarding which agent(s) and specific procedures are best in order to minimize distress. IACUCs must weigh the risks and benefits of the varied methods of rodent euthanasia. Perhaps the risk of aspiration of foreign material within the home cage is acceptable when the benefit is reduction of stress for the animals undergoing anesthesia. If Great Eastern University receives funding from the Public Health Service or is accredited by the Association for Assessment and Accreditation of Laboratory Animal Care International, then the IACUC should support the recommendations in the AVMA Guidelines. There are opposing viewpoints and varied approaches regarding the study and assessment of the impact of inhalant agents and procedures associated with rodent euthanasia. Therefore, the IACUC should review the current literature for guidance in determining what is appropriate for Great Eastern University. Institutional policies should be based on current recommendations, evidence and guidance. Efforts to improve animal welfare are ongoing, so existing practices should be continually challenged and individuals should not be discouraged from voicing their concerns. The Great Eastern University IACUC should discuss Mann’s concern so that all committee members may provide input regarding their policies. 1. Renne, R. et al. Proliferative and nonproliferative lesions of the rat and mouse respiratory tract. Toxicol. Pathol. 37, 5S–73S (2009). 2. Balcombe, J.P., Barnard, N.D. & Sandusky, C. Laboratory routines cause animal stress. Contemp. Top. Lab. Anim. Sci. 43, 42–51 (2004). 3. American Veterinary Medical Association. AVMA Guidelines for the Euthanasia of Animals: 2013 Edition (American Veterinary Medical Association, Schaumburg, IL, 2013). Na is Postdoctoral Research Fellow and Rush is Associate Professor at Unit for Laboratory Animal Medicine, University of Michigan, Ann Arbor, MI.
www.labanimal.com
Response Consider the logistics
npg
© 2015 Nature America, Inc. All rights reserved.
Laura Gallaugher, DVM, DACLAM & Laurie Goodchild, DVM
Mann does present a valid concern regarding the method of anesthesia induction. Great Eastern University’s institutional policy requiring that mice stay in their home cages during the euthanasia process might be based on the 2013 AVMA Guidelines for the Euthanasia of Animals. This document states that euthanasia should be carried out in familiar surroundings to help reduce stress1. Both the Public Health Service Policy on Humane Care and Use of Laboratory Animals and the Guide for the Care and Use of Laboratory Animals state that the euthanasia of laboratory animals must be done in accordance with the AVMA Guidelines for the Euthanasia of Animals2,3. These policies do not reference specific guidelines for the anesthesia of animals, but why should the animals be treated differently if the only difference in the procedure is whether or not the anesthetic event is terminal? Anesthesia in mice is often induced in a separate chamber, a new environment that presents unfamiliar substrates and odors and is potentially stressful. The IACUC could respond by establishing a policy that mice should be anesthetized in their home cages. There are several factors that the IACUC should consider before doing so. First, if the rodent to be anesthetized is housed with other rodents, then those animals would need to be moved, potentially causing unnecessary stress to those animals. Second, the animal’s home cage typically contains bedding. During induction, the animal may inhale the bedding, leading to an upper airway obstruction. Anesthesia chambers are devoid of objects that could cause an obstruction. Third, animal housing cages do not have adaptors for anesthetic machines, and most institutions do not have anesthesia chambers large enough to accommodate a mouse’s home cage. Logistical solutions to this would have to be explored to make this a viable option. Last, the odor of anesthetic gas itself is aversive and distressful, which might cause some animals to become anxious during induction1. Unfortunately, regardless of the environment, this stress cannot be avoided. 258 Volume 44, No. 7 | JULY 2015
A compromise that might help to reduce stress during anesthesia induction would be to place some familiar nesting material or bedding from the home cage into the chamber along with the rodent. A pilot study could address whether this small change makes a difference! 1. American Veterinary Medical Association. AVMA Guidelines for the Euthanasia of Animals: 2013 Edition (American Veterinary Medical Association, Schaumburg, IL, 2013). 2. Public Health Service. Policy on Humane Care and Use of Laboratory Animals (US Department of Health and Human Services, Washington, DC, 1986; amended 2002). 3. Institution for Laboratory Animal Research. Guide for the Care and Use of Laboratory Animals 8th edn. (National Academies Press, Washington, DC, 2011). Gallaugher is Training and Compliance Specialist and Goodchild is Clinical Veterinarian at Nationwide Children’s Hospital, Columbus, OH.
Response A valid concern Jane J. Na, DVM & Howard G. Rush, DVM, MS, DACLAM
It is appropriate for Mann to consider minimization of animal distress while reviewing this protocol, and she has a valid concern. Because Mann has never had to consider administration of an inhalant agent for anesthetic purposes, it should be explained that there would be a risk for accidental inhalation of material within the home cage that might lodge in the airway1 and potentially complicate further delivery of anesthetic, interfere with the research or adversely affect the animal during and after anesthetic recovery. From our experience, aspiration of foreign material is not common during rodent anesthesia, but introducing the animal into a clean anesthetic chamber can reduce the chance of this complication. Although there is evidence that handling and placement of a rodent into a separate chamber for induction of anesthesia is distressful2, it offers the potential benefit of preventing more distressful events or physical harm from occurring. The current AVMA Guidelines for the Euthanasia of Animals3 (AVMA Guidelines) focus on minimizing stress and m aintaining
animal comfort throughout euthanasia. Because handling a rodent elicits physiologic and behavioral changes that indicate distress2, the AVMA Guidelines recommend keeping a rodent where it is most comfortable prior to administration of inhalant agents for euthanasia3. Studies have evaluated the many factors that contribute to distress associated with the administration of inhalant agents, but the experimental design and methods used are highly variable. Because of this, there is no consensus regarding which agent(s) and specific procedures are best in order to minimize distress. IACUCs must weigh the risks and benefits of the varied methods of rodent euthanasia. Perhaps the risk of aspiration of foreign material within the home cage is acceptable when the benefit is reduction of stress for the animals undergoing anesthesia. If Great Eastern University receives funding from the Public Health Service or is accredited by the Association for Assessment and Accreditation of Laboratory Animal Care International, then the IACUC should support the recommendations in the AVMA Guidelines. There are opposing viewpoints and varied approaches regarding the study and assessment of the impact of inhalant agents and procedures associated with rodent euthanasia. Therefore, the IACUC should review the current literature for guidance in determining what is appropriate for Great Eastern University. Institutional policies should be based on current recommendations, evidence and guidance. Efforts to improve animal welfare are ongoing, so existing practices should be continually challenged and individuals should not be discouraged from voicing their concerns. The Great Eastern University IACUC should discuss Mann’s concern so that all committee members may provide input regarding their policies. 1. Renne, R. et al. Proliferative and nonproliferative lesions of the rat and mouse respiratory tract. Toxicol. Pathol. 37, 5S–73S (2009). 2. Balcombe, J.P., Barnard, N.D. & Sandusky, C. Laboratory routines cause animal stress. Contemp. Top. Lab. Anim. Sci. 43, 42–51 (2004). 3. American Veterinary Medical Association. AVMA Guidelines for the Euthanasia of Animals: 2013 Edition (American Veterinary Medical Association, Schaumburg, IL, 2013). Na is Postdoctoral Research Fellow and Rush is Associate Professor at Unit for Laboratory Animal Medicine, University of Michigan, Ann Arbor, MI.
www.labanimal.com
