A quiet death is perceived as a better death.  I’ve never heard it stated otherwise, whether human or animal.  A quiet death denotes acceptance, one without struggle or resistance.  And it’s what every pet owner asks of me during euthanasia services. They’ve either seen firsthand what the body can do as it dies….the agonal breathing, the body stretches, muscle tremors, urination/defecation, and vocalization, or they have learned about it from others who’ve seen it.  Active signs of dying in animals are normal/natural and don’t have to be suppressed, however to the observer, a quiet body is more comforting.(1) If we can reduce them to give the impression of more peaceful passing, it sounds worthwhile.  

Early on in my career, I didn’t know how to ‘adjust’ death.  My approach was to give the drugs I was told and hope for the best.  If the dog arched its head and neck or raised its tail as it died, that was that.  If the cat took deep reflexive (agonal) breaths, that was that. Over time, I learned how to leverage veterinary drugs smartly, including which ones to use and how to administer them.  Here are some tips to try yourself.

1. Opt for pre-euthanasia anesthesia rather than just sedation – inducing anesthesia in animal patients before administering euthanasia solution reduces the likelihood of active signs of death.  While not well published, there is a perceivable difference in the amount of agonal breathing, body stretching, and vocalizations in those patients who are unconscious vs those who are lightly or heavily sedated.  If you wish to reduce such signs, it is advisable to use stage 3 anesthetic dosing of ketamine, tiletamine, alfaxalone, propofol, or anesthetic gas before administering euthanasia solution. I have still experienced active signs of death while using these drugs however it is greatly reduced.
2. Wait for complete unconsciousness before administering euthanasia solution – the patient may look unconscious however waiting a few minutes longer should improve the depth of anesthesia.  
3. Administer pentobarbital euthanasia solution slowly at a rate of 0.1ml per second IV or IC to heavily sedated patients – if they are close to anesthetic depth but not quite, it’s advisable to administer euthanasia solution slowly to induce anesthesia with pentobarbital.  Pentobarbital is an anesthetic drug and slow administration will impart stage 3 anesthesia (surgical depth) before moving the patient into coma and death.  This anesthesia should reduce agonal breathing, body stretches, and vocalization.  Note that if your patient is awake when you begin administering pentobarbital, the administration rate is much faster at 1ml per second to help overcome anesthetic stages 1 and 2 more rapidly.
4. Acupressure on LIV 3 – it’s been proposed that pressure applied to the acupuncture point Liver 3 on the back foot may reduce active signs of death during euthanasia. While more research on this technique is needed, there is no harm in trying it.(2) 

Paralytics have been used in human medicine to reduce agonal breathing however they are not given as stand alone agents in vet med.  The euthanasia solution T-61 contains the paralytic agent mebezonium iodide, which produces a curariform paralytic action on striated skeletal and respiratory muscles.(3)  This reduces the likelihood of agonal breathing.

Pet owners and veterinarians dislike active signs of death during euthanasia.  Since the dying pet is unaware they are occurring, agonal breathing, vocalization, and body stretches are not considered part of a dysthanasia, however in my experience, pet owners may be left wondering if their pet suffered during death.  Veterinary teams should inform pet owners that active signs of death are normal before euthanasia begins and address them afterwards if they occur.  The takeaway is that while unappealing, everything is ok.  

1. https://www.avma.org/sites/default/files/2020-02/Guidelines-on-Euthanasia-2020.pdf, pg 14.
2. Shearer, T. (2020) Nonpharmacologic Methods to Improve the Euthanasia Experience. Vet. Clin. N. Am. Small Anim. Pract. 50, 627–638.
3. https://www.drugs.com/vet/t-61-euthanasia-solution-can.html