In My Experience—Rethinking Propofol

Propofol became available to veterinary medicine in the early 1990s and is a staple drug these days. We rely on it for smooth anesthetic induction for both short and long procedures. It is reliable and very recognizable.

By Kathleen Cooney, DVM, CHPV, DACAW

Is Propofol During Euthanasia Doing More Harm Than Good?

As good as propofol has been as a pre-euthanasia anesthetic, times are changing. It’s possible that holding on to propofol’s use is slowing progress toward more modern euthanasia protocols, especially in hospitals trying to elevate patient care. Patients benefit when everything is done to keep the procedure free of pain and anxiety, and today, this is best facilitated by giving sedatives and anesthetics before intravenous (IV) catheter placement is attempted. Clients want their pet sleeping and pain-free in their final moments.1 They also want the chance to remain with their pet during the entirety of the appointment. In a time when exceeding client expectations is the norm, perhaps a pre-euthanasia propofol fade-out is worth exploring.

Why Do We Use Propofol Before Euthanasia?

The search for the perfect smooth euthanasia procedure has been in the making for a long time. Many have sought to find the perfect euthanasia solution and/or something useful before the procedure to soften the effects of the drugs we use.2, 3 Pentobarbital, the most common euthanasia solution here in the United States, is reliable by itself when properly dosed and is leveraged for a variety of species.4 It remains the gold standard for companion animals, and while good at achieving death, can generate active signs of death (e.g., agonal breaths, vocalization, muscle tremors) that are unpleasant for clients and veterinary personnel to see.5, 6, 7, 8 The ideal scenario is a patient that succumbs quickly to the euthanasia solution, as if to welcome a permanent deep sleep with no evidence of knowing it’s even happening.

GettyImages-1258520950.jpgPropofol became available to veterinary medicine in the early 1990s and is a staple drug these days. We rely on it for smooth anesthetic induction for both short and long procedures. It is reliable and very recognizable. You see a syringe of white solution and know what it’s for. For decades now, veterinarians and technicians have used propofol as part of a two-step euthanasia process: administer propofol IV, then administer pentobarbital. Because propofol must be given into the vein, the animal patient is traditionally brought to the treatment area where the staff will place an indwelling IV catheter, then be returned to its owner for the procedure.

I was unable to track down exactly how propofol gained such popularity as a pre-euthanasia agent. I’m sure the quick anesthesia effects and desire by practitioners to reduce active signs of death during euthanasia made it attractive. In 2019, however, a study revealed that propofol before pentobarbital has minimal benefits in this regard. Its use does appear to reduce some perimortem muscle activity and patient vocalization during euthanasia, although it does not have much effect on agonal breathing.9, 10 Agonal breathing is a normal reflexive response during death and is difficult for both clients and staff to see when they aren’t prepared for it. The rate of pentobarbital administration may have something to do with that11 but was not included in the study.

The main perks, then, are that propofol renders a patient unconscious before pentobarbital is given. This unconsciousness removes the need for any further restraint, lessens the risk of dysphoria from pentobarbital, and reduces at least some active signs of death.12 Propofol also removes the starkness of death. I’ve heard many pet owners mention how difficult it was to see the “light” leave their awake pet’s eyes during euthanasia. Using propofol to induce that ultra-deep sleep is like a rehearsal for the death itself. Clients see their pet peaceful and pain-free in their final moments, no longer moving or responding to sounds. As we will see, other anesthetics do all this, too, and with no need for venous access.

The Opportunity for Something Better

The main disadvantage of propofol is a big one. It must be injected into a vein. Propofol is ineffective when given intramuscularly and will create significant tissue damage.13 Venous access in awake patients means restraint, and this usually means the patient will be separated from its owners for the trip back to the treatment area for IV catheter placement. Can we keep the benefits that propofol has and remove this disadvantage?

Since the goal is to reduce fear, anxiety, and stress (FAS) during euthanasia, it makes sense to provide an anesthetic well before any technical aspects of euthanasia begin.

The AVMA noted in their euthanasia guidelines that presedation or anesthesia should be provided for patients whenever practicable.14 I’m on board with this 100%. What they didn’t exactly specify is when to give it. Since the goal is to reduce fear, anxiety, and stress (FAS) during euthanasia, it makes sense to provide an anesthetic well before any technical aspects of euthanasia begin, and by this, I mean restraint for IV access, clipping fur, and the euthanasia solution injection itself. We have other anesthetics like ketamine, tiletamine, and alfaxalone ready for intramuscular injection that require minimal restraint in canine and feline patients. Euthanasia techniques have also evolved in recent years so that venous access isn’t even necessary. Pentobarbital can be given in other areas of high perfusion in the body, allowing staff to avoid veins altogether which is advantageous when blood pressures are poor or veins hard to find.15

Avoiding the Treatment Area

IMG_0507.jpgThe treatment area can be a scary place with all its sights, smells, and sounds. Non-propofol anesthetics like ketamine, tiletamine, or alfaxalone may be given to the patient in the examination/comfort room. The patient may be offered treats and other distractions while the drug combinations are given. Veterinary support staff can work together with the client in the room to safely give the anesthetics with the least amount of pain or anxiety to the patient. After the injection is complete, the patient spends time with the client, being supported and loved. Once they are sleeping, then the IV catheter is placed with the patient unaware. The goal is for them to succumb to sleep with minimal restraint and discomfort, in line with modern euthanasia practices.

If you think of it with the idea that the patient enters the comfort room alive, and will only leave it deceased, you are on the right track. All equipment one needs for euthanasia will be brought into the room, including cordless clippers, med supplies including all drugs, and memorialization items that can be made and sent home with the client. Euthanasia patients are already compromised (physically and/or emotionally), so keeping them out of the treatment area is beneficial. Reducing stress includes keeping them in safe and familiar surroundings (one room, not two), and with fewer people.16, 17

If you think of it with the idea that the patient enters the comfort room alive, and will only leave it deceased, you are on the right track.

What makes propofol worth avoiding is the tendency or potential to default to the old way of doing things. Old way: Separate patient to treatment area, restrain, place IV catheter, return to client after stressful event. New way: Keep patient in the examination/comfort room, give intramuscular (or subcutaneous or oral) anesthetic drug combination, allow patient to fall asleep with owner, place IV catheter (or use the intraorgan method), and administer euthanasia.

The veterinary team will need to agree that reducing FAS during euthanasia is important and impart protocol upgrades accordingly. I have seen many hospitals improve morale and team wellbeing by making this simple switch. Propofol will still have its usefulness for short procedures and surgical induction, and if an IV catheter is already placed following hospitalization, by all means, use it before euthanasia.

Animal Hospice & Palliative Care Certificate Program

The Animal Hospice & Palliative Care Certificate Program is an online continuing education course covering topics in animal hospice, palliative care, and the euthanasia experience. The program is presented by Kathleen Cooney, DVM, CHPV, DACAW resident. Learn more at: aaha.org/education/online-training/animal-hospice–palliative-care-certificate-program.

Read an interview with Kathleen Cooney, DVM, CHPV, DACAW resident, in this issue: Can Euthanasia Be Beautiful?

Closing Thoughts

Euthanasia has evolved to be more than the act of giving pentobarbital. The patient’s wellbeing is related to the time leading up to death as much as the moment of death itself. When considering companion animal euthanasia, clients want and expect more for their pets. Propofol as a pre-euthanasia anesthetic after IV catheter placement was once the gold standard, but the new gold standard says the patient should be sedated or anesthetized beforehand and to keep the patient with the client for the duration. With new nonvenous techniques gaining traction too, requiring the propofol protocol like the old days may do more harm than good for patients, clients, and veterinary teams.

Cooney_Kathleen_BioPhoto.jpg
Kathleen Cooney, DVM, CHPV, DACAW resident, is Senior Director of Medical Education for the Companion Animal Euthanasia Training Academy (CAETA). She is a well-known speaker, author, and researcher pertaining to all manner of euthanasia-related topics. Cooney can be reached at kathleen@caetainternational.com.

Photo credits: Todorean Gabriel/iStock via Getty Images Plus, PDerrett/E+ via Getty Images, ©AAHA/Robin Taylor

References

1 Cooney, K.; Kogan, L. “How Pet Owners Define a ‘Good Death.’” dvm360 2022, 53 (8), 12.

2 Evans, A. T.; Broadstone, R.; Stapleton, J.; Hooks, T. M.; Johnston, S. M.; McNeil, J. R. “Comparison of Pentobarbital Alone and Pentobarbital in Combination with Lidocaine for Euthanasia of Dogs.” J. Am. Vet. Med. Assoc. 1993, 203 (5), 664–66.

3 Cooney, K. “Historical Perspective of Euthanasia in Veterinary Medicine.” Vet. Clin. North Am. Small Anim. Pract. 2020, 50 (3), 489–502. doi.org/10.1016/ j.cvsm.2019.12.001.

4 Leary, S.; Pharmaceuticals, F.; Underwood, W.; Anthony, R.; Cartner, S.; Johnson, C. L.; Patterson-Kane, E. AVMA Guidelines for the Euthanasia of Animals: 2020 Edition.

5 Deponti, P. S.; Jaguezeski, A. M.; Pulgatti, D. H. V.; Soares, J. C. M.; Cecim, M. da S. “Veterinarian’s Perceptions of Animal Euthanasia and the Relation to Their Own Mental Health.” Ciênc. Rural 2023, 53 (5), e20210578. doi.org/ 10.1590/0103-8478cr20210578.

6 Robertson, S. A. “Pharmacologic Methods: An Update on Optimal Presedation and Euthanasia Solution Administration.” Vet. Clin. North Am. Small Anim. Pract. 2020, 50 (3), 525–543. doi.org/10.1016/ j.cvsm.2019.12.004.

7 Martin, F.; Ruby, K. L.; Deking, T. M.; Taunton, A. E. “Factors Associated with Client, Staff, and Student Satisfaction Regarding Small Animal Euthanasia Procedures at a Veterinary Teaching Hospital.” J. Am. Vet. Med. Assoc. 2004, 224 (11), 1774–79. doi.org/10.2460/javma.2004.224.1774.

8 Matte, A. R.; Khosa, D. K.; Coe, J. B.; Meehan, M.; Niel, L. “Exploring Pet Owners’ Experiences and Self-Reported Satisfaction and Grief Following Companion Animal Euthanasia.” Vet. Rec. 2020, 187 (12), e122. doi.org/10.1136/vr.105734.

9 Bullock, J. M.; Lanaux, T. M.; Shmalberg, J. W. “Comparison of Pentobarbital-Phenytoin Alone vs Propofol Prior to Pentobarbital-Phenytoin for Euthanasia in 436 Client-Owned Dogs.” J. Vet. Emerg. Crit. Care 2019, 29 (2), 161–65. doi.org/10.1111/vec.12813.

10 Lee, J. “The use of propofol during euthanasia in veterinary medicine.” VETgirl Veterinary Continuing Education Blog. VETgirl. Accessed May 31, 2023. vetgirlontherun.com/the-use-of- propofol-during-euthanasia- in-veterinary-medicine-vetgirl-veterinar-continuing-education-blog.

11 Clinician’s Brief. “Euthanasia Protocols.” Accessed May 30, 2023. cliniciansbrief.com/article/euthanasia-protocols.

12 Cooney, K. “Common and Alternative Routes of Euthanasia Solution Administration.” Vet. Clin. North Am. Small Anim. Pract. 2020, 50. doi.org/10.1016/ j.cvsm.2019.12.005.

13 McKune, C. M.; Brosnan, R. J.; Dark, M. J.; Haldorson, G. J. “Safety and Efficacy of Intramuscular Propofol Administration in Rats.” Vet. Anaesth. Analg. 2008, 35 (6), 495–500. doi.org/10.1111/j.1467-2995.2008.00418.x.

14 Lloyd, J. K. F. “Minimising Stress for Patients in the Veterinary Hospital: Why It Is Important and What Can Be Done about It.” Vet. Sci. 2017, 4 (2), 22. doi.org/10.3390/vetsci4020022.

15 Cooney, K. “Common and Alternative Routes of Euthanasia Solution Administration.” Vet. Clin. North Am. Small Anim. Pract. 2020, 50. doi.org/10.1016/ j.cvsm.2019.12.005.

16 Lloyd, J. K. F. “Minimising Stress for Patients in the Veterinary Hospital: Why It Is Important and What Can Be Done about It.” Vet. Sci. 2017, 4 (2), 22. doi.org/10.3390/vetsci4020022.

17 DVM360. “Reducing Stress in Hospitalized Patients.” Accessed May 30, 2023. dvm360.com/view/reducing-stress-in-hospitalized-patients.

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