C. Giraldo-Arboleda, J. C. Zapata-Martinez, L. Osorio-Morales and F. Pedraza-Ordóñez*
Abstract
Euthanasia is a highly controversial issue in human society. In the field of veterinary medicine, there are guidelines that are intended to assist with the decision-making around euthanasia and reduce the possible ethical and moral conflicts involved with these situations. In this review, we have collected the existing information that allows veterinarians to better understand the factors surrounding the practice of euthanasia.
Specific literature on topics such as the pathophysiology of pain in animals, clinical situations that could lead to a decision to euthanise an animal, possible ethical and moral conflicts, the management of emotions by animal tutors, etc. This article provides a general and practical overview of this potentially complex issue for the benefit of students, veterinarians, and the general public from both an ethical and medical point of view, and covers the fundamental concepts and notions that can facilitate decision-making concerning the euthanasia of animals. Ethical practices in veterinary medicine and the correct application of animal welfare principals are central to making such decisions responsibly.Key words: euthanasia; companion animals; one health; animal welfare; minimal damage; justice
Introduction
There is concrete evidence that dogs can understand human emotions, gestures and actions, and of how these animals have formed a part of human culture (Benz-Sw et al., 2020; Strakova et al., 2020). As in all social relationships, there may be a preference of the companion animal for one of the family members, which is generally the person who spends more time with it outdoors (Carlone et al., 2019). These relationships also involve decision-making about the health and wellbeing of the animal, e.g., keeping it alive due to the importance of the friendship with its tutor, notwithstanding the occurrence of ailments and illnesses, versus ending that suffering through euthanasia. These situations always place tutors and veterinarians in a series of personal, professional, moral and ethical conflicts (Cabrejo, 2016).
The application of euthanasia in animal patients with intolerable and incurable suffering, understood as the act of inducing a calm and easy death without stress or pain, requires the use of well-constructed medical criteria (Vanda-Cantón, 2003). It is ultimately a task to be performed by a veterinarian, but is not a decision that is made unilaterally. The views of the tutors, as providers of care and affection, should also be taken into account, as they have good knowledge of the companion animal’s temperament (Sivula and Suckow, 2018). The veterinarian has a responsibility to provide all relevant information to the tutor to enable joint decision-making and this must be done in a clear, honest, and well-argued manner with no pressure by the veterinarian, and that generates emotional support.
In effect, these deliberations should be made in a way that fosters trust and peace of mind so that the best decision is being made at such a painful and confusing time for the people involved.
Unfortunately, there is little training for the professionals involved in animal care to communicate bad news and provide support to the tutor (Henao-Villegas, 2017; Nickels and Feeley, 2017).
The concept of animal welfare
To provide for the needs of any animal species, guidelines for care will include death at the right time. For this reason, a method must be used that minimises suffering that may be caused in cases where euthanasia is required (OIE, 2019). The principle of animal freedoms promulgated by the OIE has some critics who find it too generic and difficult to guarantee. An example of this is freeing the animal from fear and anguish at the time of death (Solano and Rivadeneira, 2015; Mellor, 2016; Pettorali, 2016). It was for this reason that a paradigm shift was proposed so that freedoms would be replaced by domains, with actions that foster animal welfare and could be easily understood by non-expert personnel.
In this way, instead of freedom from pain and illness or freedom from fear and anguish, “prevention” or “rapid diagnosis and treatment” have been proposed, ensuring conditions that avoid the mental suffering of the animal (Mellor, 2016). Mellor (2017) proposes to apply a model of five domains: nutrition, environment, health, behaviour and mental state, with a significant focus on subjective experiences known as effects, which contribute to an animal’s overall wellbeing. On the other hand, universities in Australia and New Zealand have developed an online portal called the One Welfare Portal, where information on key topics in animal welfare and ethics, and their interaction with human and environmental welfare, can be accessed (McGreevy et al., 2020).
Respecting an animal means being informed about its needs and desires with regard to nutrition, exercise, health care, and socialisation. The human-animal relationship comes with clear relationships in terms of power and responsibilities on the part of whoever exercises that power (Stephens and Hill, 1996; Benz-Sw et al., 2020). It is necessary to protect animals from man-made dangers (such as traffic accidents, for example) and to have the generosity of spirit not to adopt an animal if its needs cannot be met. Some situations such as the restriction on tenants with companion animals or legislation around the possession of dogs trained in attack or fighting, among other reasons, have triggered the abandonment of animals, which is becoming a particular problem in the United States (Stephens and Hill, 1996; O’Reilly-Jones, 2019).
Domestic violence against animals is also an issue and veterinarians play an important role in preventing this (particularly as educators of care and respect for vulnerable non-humans).
Moreover, although this role has only been considered in the past two decades, it is not yet widely accepted (Monsalve et al., 2017). One of the orientations of “One Welfare” points to the worldwide reduction of crime and violence, particularly against the vulnerable (children, women and the elderly). In this regard, animal and human abuse sometimes occur simultaneously (García-Pinillos et al., 2015; Herbert-Garrido, 2020). Indeed, animals are often good indicators of human health or abuse. There is evidence showing that people who mistreat animals generally also abuse or mistreat human beings.
Identifying episodes of animal abuse inflicted by children and adolescents is vital to prevent future antisocial behaviours (García Pinillos et al., 2015; Longobardi and Badenes-Ribera, 2019).
The assessment of pain in animals
Pain scales designed for assessments in humans have been adapted for veterinary use, and most are used to determine postoperative pain. The evaluation of pain in animals is subjective and complex and the veterinarian must be able to recognise it early to establish effective treatment (Noreña-Tobón, 2018; Parra, 2019).
Scales to classify pain are very useful and can be unidimensional or multidimensional. The first of these were simple in design and were based on visual examinations. The second group of scales are more complex and evaluate different aspects that an animal with pain can express (Clark et al., 2002; Daeninck et al., 2016). Only the most used in the clinic are mentioned in this review and are described below.
- Canine Glasgow Scale: Measures acute post-operative pain and is the best validated assessment tool in dogs because of the consistency of the results among different operators. The test includes an assessment of posture, comfort, vocalisation, attention to the wound, response to the presence of people, mobility and response to touch (Hellyer et al., 2013). There is a widely used short form of this tool which uses a multimodal behaviour-based scale and is intended only for dogs with acute pain (Murrell et al., 2008).
- Canine Melbourne Scale: This is a multimodal tool that assesses postoperative pain in dogs through behavioural analysis and also incorporates physiological data such as heart rate, respiratory rate, pupil size and temperature (Firth and Haldane, 1999).
- Feline Glasgow Scale: This is a multimodal tool for evaluating acute pain in cats and uses psychometric principles and a three-point facial scale to refine the understanding of the tool, which in previous tests worked well for classifying pain in cats (Reid et al., 2017).
- Feline Botucatu Scale: This tool was at Sao Paulo State University (Brazil). It is a reliable method and can sensitively assess postoperative pain in cats with oophorosalpingohysterectomy.
It relates behavioural observations to reliable clinical pain measurement parameters (Brondani et al., 2011). - Feline Colorado Scale: Although there is no ‘gold standard’ system for pain assessment in cats, this scale is the easiest to use. It begins with an observation of the animal in a cage, followed by an assessment of its response gentle palpation of a wound or painful region. Among the advantages of this method is the provision of specific descriptors for individual behaviours, thereby reducing variability between observers (Maddison and Murrell, 2015).
In the context of pain assessment and management in animals, it is imperative to consider the basic principles of bioethics, specifically those related to minimum harm, and the principle of justice.
Regarding the former, the ancient expression attributed to Hippocrates, primun non nocere, i.e., “first do no harm”, is a reminder that any intervention can cause considerable and avoidable damage. In other words, the safety of the patient comes first, and doctors must be committed to this (Aliaga-Gutiérrez, 2019).
The latter is related to the basic aim of protecting the weak and vulnerable from harm, with the understanding that animals have the right to lead a prosperous life and humans should help to foster this (Haynes, 2016).
Definition of euthanasia
Factors associated with euthanasia
Criteria for euthanasia
Some cases appear to be so serious that euthanasia emerges quickly as the only viable intervention. However, there can sometimes be options for therapeutic resolution even in these cases. By contrast, some cases that appear not to be so medically serious can sometimes satisfy the criteria for the consideration of euthanasia (Leary et al., 2020). The diseases in such instances can include metastatic malignant neoplasms, cardiovascular disease, urogenital or digestive disorders without possible resolution, reduced mobility without the possibility of improving with mechanical prosthetic supports (such as wheelchairs), and other situations in which, although they have been described as causes of death, it is necessary to determine that there is no other viable solution to ensure the animal’s wellbeing. These other situations can include urinary and faecal incontinence, confusion, sleep disturbance, weakness, weight loss, anxiety and anorexia (Marchitelli et al., 2020). Generally, a combination of factors leads to the decision to euthanise.
Malignant neoplasms with a poor prognosis and an advanced clinical status are a good example of a situation where there can be certainty that euthanasia is the most appropriate intervention to avoid prolonged suffering of the animal (as long as there is diagnostic support from histopathology, imaging and appropriate paraclinical tests). In cases that could undergo palliative treatment, the prognosis must be clearly established and informed consent given, so that the tutor can understand which option is most appropriate for the wellbeing of the animal (Leary et al., 2020). Non-medical conditions such as the financial capacity of the tutor may also be related to this decision. One study has found that people with low incomes are more likely to opt for prompt euthanasia by their veterinarian, while people with higher incomes more frequently considered prolonging the life of their companion animal through palliative care (Shibly et al., 2014; Spitznagel et al., 2020).
Evaluation of euthanasia methods according to their effect
The method must be painless, fast, easy to administer, economical, effective and must not interfere with the most common post-mortem tests. Known euthanasia methods are listed in Table 1 along with their current classifications as acceptable, conditionally acceptable or unacceptable (Allende, 2017; Sivula and Suckow, 2018).
Pharmacological methods
Its bioavailability by the oral route is low.
Gabapentin (antiepileptic) is used orally in cats to reduce stress and anxiety prior to euthanasia. Its smell and taste are not strong and it is easy to ingest. Melatonin has very good results as a calming agent in dogs and pentobarbital powder accelerates the onset of sedation and anaesthesia (Robertson, 2020).
Methods of enhancing the euthanasia experience
The movements may be involuntary or may occur after moving the cadaver by mechanical extension of the spinal roots or direct compression of the spinal cord.
Although the pathophysiological mechanism for their presentation is not completely clear, it is known that they are responses originating in the spinal cord (Martínez-Roldan et al., 2015). It has also been proposed that neuronal interconnections, “central generators” of the spinal cord, could be involved in the generation of involuntary movements (mainly described in brain-dead humans), however, there are no well-documented studies that demonstrate these phenomena (Saposnik et al., 2009; Leary et al., 2020; Shearer, 2020).
Another controversial aspect of euthanasia in animals lies in the disposition of the corpse as many tutors will relate their religious beliefs to the death of their companion animals, even thinking about their life after death. A study carried out in the United Kingdom of the epitaphs and the designs of animal tombstones since the 19th century has revealed the direct expression of some of these beliefs.
Some animal clinics even provide a chaplain service for spiritual help during the grieving process (Cooney, 2020; Touringny, 2020). More recently, the cremation of animal corpses has become popular and a service is even provided for the tutors through a family funeral plan. In Western cultures, there are still diverse perceptions regarding the meaning of death. In Latin American countries, strong Judeo-Christian influences have led to acceptance of this concept as something distant from one’s own understanding and thus when facing the loss of someone close, it is difficult to understand it as a process that is part of life itself (Caycedo-Bustos, 2007; Bonilla, 2015). In this sense, human-animal studies should focus on humans as animals (biologically speaking) and their relationship with other species, taking into account that originally in human-animal interactions, animals were seen as providers of resources, emotions and protection (Díaz-Videla et al., 2015). In contrast to the feelings of some tutors who strive to give a proper farewell to their companion animal, there are others who dispose of corpses in an inappropriate manner, making it necessary to establish a legal framework that punishes this type of act. Under no circumstances should euthanized animal corpses be abandoned to the environment. In addition to the bioethical and legal reasons against this, the barbiturates used for euthanasia would be highly toxic to any wildlife that might feed on these corpses (Heiblum and Tejada, 2007; Leary et al., 2020).
Management of abandoned or free-roaming dogs
In these cases, the bioethical principles of minimum harm and justice are lacking and the animals often end up in shelters where overcrowding and the consequent spread of infectious diseases (including the risk of zoonoses) often occur. These circumstances will ultimately precipitate the difficult decision to euthanise some of them. In several countries, controlling the overpopulation of stray animals (mass killing) can be carried out using lethal methods such as the application of chemical agents, such as sodium pentobarbital. This differs from the application of euthanasia to help animals with terminal illnesses that cause unbearable pain. The effective solution to the problem of street dogs and cats are education programmes to prevent the abandonment of animals together with sterilisation programs, the scope of which will be observed in the long term (Valencia, 2012). Mass killing is included in article 7.6.1 of the OIE Terrestrial Animal Health Code (OIE 2021, Kachani et al., 2014).
The experience of euthanasia in veterinary hospitals
Most tutors are now aware of the different forms of palliative care, with euthanasia being the last option. Medical alternatives such as pain management, infection control, and delaying the progression of malignancy will now typically be considered first (Cooney, 2020). In addition, some university hospitals already have significant experiences providing thanatology and social work services to bereaved tutors. For example, the Hospitals of the Universities of Pennsylvania, Tufts, Michigan, Florida and California Davis, among others, have established direct support lines to provide such services (Stephens and Hill, 1996).
On site euthanasia
The importance of overcoming the stresses involved with practicing animal euthanasia
Final considerations
Companion animals have undoubtedly become members of a multispecies family and any event related to their health is cause for concern to their tutors. There is a global movement for the protection and care of animals that is becoming stronger through platforms such as “One Welfare”. In this context, talking about euthanasia becomes one of the main ethical and moral challenges for veterinarians, added to incomplete training on this subject in educational centres. It is vital that university courses discuss the ethical, legal and sociocultural aspects of the way veterinary surgeons relate to the animals in their care and to the decisions made around them, always from the perspective of non-maleficence and justice.
It is clear that the decision to euthanise must follow medical parameters and be applied only in very specific and extreme cases. Pre-euthanasia medications should always be used and, depending on the method used, sometimes general anaesthesia. The negative consequences of the veterinarian’s decision to euthanise should also not be underestimated. The mental health of these professionals must be supported by psychologists and thanatologists. In the same way, there must be support for tutor from the moment that the decision to euthanise is made, which is also essential for the wellbeing of all those involved in this process.
References [… show]
Etička i znanstvena razmatranja kod donošenja odluka o eutanaziji kućnih ljubimaca
Carolina GIRALDO-ARBOLEDA, DVM, Juan Carlos ZAPATA-MARTINEZ, DVM, Veterinary Medicine Program, Corporación Universitaria Santa Rosa de Cabal – UNISARC, Santa Rosa de Cabal, Colombia; Lina OSORIO-MORALES, DVM, MSc, Veterinary Pathology Research Group, Universidad de Caldas, Manizales, Colombia, Associated Professor Veterinary Medicine Program, Corporación Universitaria Santa Rosa de Cabal – UNISARC, Santa Rosa de Cabal, Colombia; Francisco PEDRAZA-ORDÓÑEZ, DVM, PhD, Titular Professor, Animal Health Department, Universidad de Caldas, Manizales, Colombia
E utanazija je izuzetno kompleksno i odgovorno pitanje i u ljudskom i u životinjskom svijetu. Na području veterinarstva postavljene su smjernice čiji je cilj pomoći u donošenja odluke o eutanaziji i smanjenju moguće moralne dvojbe u donošenju odluke o izvršiti ili ne izvršiti euatanaziju. U ovom članku, prikupili smo valjana rješenja koja pomažu veterinaru bolje razumjeti okolnosti u donošenju odluke o eutanaziji životinje. Posebna literatura o temama poput patofiziologije boli kod životinja, kliničkih situacija koje pomažu u donošenju odluke o eutanaziji životinje, mogućih moralnih dvojbi i dogovora s vlasnikom životinje. Ovaj članak pruža opći i praktični pregled ovog trajno dvojbenog pitanja koje će koristiti studentima, veterinarima i javnosti s moralnog, kao i medicinskog rješenja i pokriva osnovne ideje i pojmove koji mogu olakšati donošenje odluke u svezi eutanazije životinje. Moralne prakse u veterinarstvu i ispravna primjena principa dobrobiti životinje ključne su za odgovorno donošenje odluke.Ključne riječi: eutanazija, kućni ljubimci, jedno zdravlje, dobrobit životinja, minimalna šteta, pravda