Guidelines for euthanasia

© University of Minnesota; http://www.ahc.umn.edu/rar/euthanasia.html

Animals are usually euthanased because they are experiencing unrelenting pain or distress. Euthanasia is defined as a pain-free or stress-free death. The IACUC (Institutional Animal Care and Use Committee - www.iacuc.org) has approved certain methods for humanely killing animals that meet the definition of euthanasia. The appropriateness of the method may vary from species to species.  Euthanasia of animals is expected if animals demonstrate the conditions listed below, whether the animal has been manipulated or not. Additional criteria may be specified on the Animal Usage Form. Fulfilment of one criterion can constitute grounds for euthanasia. Exceptions are permitted only if approved by the IACUC as part of the protocol review process (i.e. the clinical signs listed below are expected as part of the experiment and appropriate measures are taken to minimize pain or discomfort in the animals). 

  • Weight loss: loss of 20-25% (depending on attitude, weight recorded at time of arrival, and age: growing animals may not lose weight, but may not gain normally) or if not measured, characterized by cachexia and muscle wasting.

  • Inappetence: complete anorexia for 24 hours in small rodents, up to 5 days in large animals; partial anorexia (less than 50% of caloric requirement) for 3 days in small rodents, 7 days in large animals.

  • Weakness/inability to obtain feed or water: Inability or extreme reluctance to stand which persists for 24 hours, assuming that the animal has recovered from anaesthesia.

  • Moribund state: depression coupled with body temperature below 99 F, or non-responsive to stimulation, assuming that the animal has recovered from anaesthesia.

  • Infection: infection involving any organ system (either overt, or indicated by increased body temperature or WBC parameters) which fails to respond to antibiotic therapy within an appropriate time and is accompanied by systemic signs of illness.

  • Signs of severe organ system dysfunction non-responsive to treatment, or with a poor prognosis as determined by a registered veterinarian: e.g. Respiratory: dyspnea, cyanosis. 

  • Cardiovascular: blood loss or anaemia resulting in hematocrit below 20%; one transfusion may be performed. 

  • Gastrointestinal: severe vomiting or diarrhoea, obstruction, intussusception; peritonitis, evisceration (immediate euthanasia required). 

  • Urogenital: renal failure characterized by elevated BUN, creatinine or uroperitoneum. 

  • Nervous: CNS depression, seizures, paralysis of one or more extremities; pain unresponsive to analgesic therapy. 

  • Musculoskeletal: muscle damage, bone injury, locomotor deficits, etc. resulting in inability to use the limb, unless anticipated as part of the study. 

  • Integumentary: Non-healing wounds, repeated self-trauma, second or third degree heating pad burns.

Euthanasia from a veterinary perspective

Eventually, each companion animal guardian must face the dilemma of euthanasia. When a pet is medically evaluated by a veterinarian, it is the guardian's responsibility to determine whether or not to provide treatment. Euthanasia may relieve or stress the pet's guardian, depending on the circumstances. In many cases, the pet is critically ill with no chance for recovery. Euthanasia may be suggested as a compassionate alternative to a lingering death encumbered with pain and suffering. The burden of the decision can be overwhelming and fraught with feelings of desperation, denial, anger, and guilt. What is needed at that time is a rational basis for a decision. Some diseases, including cancer, can be treated, offering a measure of life extension. In such instances, euthanasia is not the only alternative. Other conditions, such as renal failure, congestive heart failure, or some forms of metabolic disease, may offer no hope at all. Euthanasia then becomes the only humane consideration.

Pets offer companionship, emotional intimacy, and feelings of well-being to their caretakers. Humans should create happy, pleasurable lives for their pets. When well-being turns to suffering, alternatives should be considered. As long as an ailing animal is enjoying life without pain, there is justification for his continued presence. The quality of life, not quantity of life, can help the guardian determine the pet's reason for living.

Euthanasia is a nearly painless process. Most veterinarians give an injection of a powerful barbiturate anaesthetic that first causes the animal to become unconscious, usually within about three seconds of injection. Most of the time, this injection is given in a vein in the front leg. The veterinarian will probably give the pet a relaxing dose of a sedative or a gas anaesthetic first, to eliminate any possibility of anxiety or discomfort. In very old pets or those with severe kidney or heart failure, the veins may be too fragile or collapsed because of low blood pressure. These pets can be given an injection directly into the heart.

The drug acts on the brain and heart to cause the breathing and heartbeat to stop. There is no pain, except for the initial prick of the needle. That can be avoided too, if an intravenous catheter is already in place due to an illness. Sometimes the animal may sigh, move, or void. These are just reflexes. The animal doesn't feel pain - or anything whatsoever. Death follows unconsciousness within two minutes.

Euthanasia can be very emotional for veterinarians as well. Sometimes the veterinarian has known the pet for a long time or has worked hard in trying to prolong the life of the pet. English veterinarian/author James Herriot stated the view of most veterinarians in his book All Things Wise and Wonderful:

"Like all vets I hated doing this, painless though it was, but to me there has always been a comfort in the knowledge that the last thing these helpless animals knew was the sound of a friendly voice and the touch of a gentle hand."

Grieving will be a natural and necessary part of accepting the loss of a pet. Many support groups have been organized within communities, the Internet community, veterinary schools, and local mental health organizations to help people go through what can be a very painful process. Your veterinarian may know of a local support group or individual who provides counselling.

Unlike humans, animals seem to have no concept of death, although all animals do fear death. There isn't apprehension, traumatic fear, or pain when the inevitable occurs. There is simply unending, peaceful sleep - and our cherished memories.