A New Approach to Intracardiac Euthanasia Injections in Small Animals

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For many years, the Companion Animal Euthanasia Training Academy (CAETA), has taught the intracardiac euthanasia technique in one particular manner for companion animals. I’ll call it “the common way,” which is to insert the needle into the heart from the lateral side of the chest wall, aiming perpendicular to reach a ventricle, atrium, or honestly, any “heart-ish” space that contains blood to tell us we are in the right location. Intracardiac injections are an alternative to intravenous injections when veins are difficult to find. The heart is like a large vessel with muscle around it, and it provides a very effective way of delivering pentobarbital euthanasia solution to the brain. The common way is tricky for two reasons: it can be difficult to locate the heart and results in an intake of blood into the syringe that clients may not like.

This flash of blood in the syringe is an ever-present concern for veterinarians. In a recent study asking veterinarians to define a good death, I surveyed vets on which euthanasia technique they least preferred doing with clients present. Some 82% indicated that performing an intracardiac injection in a room of onlookers was very uncomfortable. They were concerned about locating the heart quickly and efficiently and didn’t want their clients to see blood in the syringe. In my experience teaching a euthanasia technique lab for the past 10+ years, veterinarians worry about it a lot. It’s part of the reason why intrahepatic and intrarenal injections have gained popularity.

The best way to prevent seeing blood in the syringe when injecting into the lateral side of the chest wall is to use a needle, syringe, and small extension set. As taught to us by the esteemed veterinarian, Dr. Anthony Smith, by attaching a small extension set in between the needle and syringe, the blood flows into the extension and not into the syringe. The extension can be curled into the palm of the hand, more effectively hiding the blood from view. This technique works very well when the heart is accessed through the lateral side.

In recent months, I’ve been using a different intracardiac euthanasia approach. Rather than aiming for the lateral chest wall in the region I know the heart to be, I’ve been inserting the needle ventral midline, from the point of the sternum aiming cranial just inside the sternum to reach the apex of the heart. Because the needle enters the body from the ventral side, it’s less visible to loved ones gathered near the head or back side of the patient. The needle is inserted slowly, almost parallel to the sternum; no more than 10 degrees dorsally. Intrahepatic injections are typically aimed at 45 degrees. When the heart is located, I’ve found the pulsations actually push blood into the syringe, possibly eliminating the need to draw back on the syringe for negative pressure.

Tips for Ventral Intracardiac Euthanasia Injections

1.  Lay the patient in lateral recumbency.

2.  Ensure the patient is completely unconscious before starting.

3.  Insert the needle at the point of the sternum, aiming cranial and midline up toward the heart (Measure the needle length before insertion to make sure it’s long enough to reach the heart. A 1.5 to 4-inch needle may be required, depending on the length of the chest. A 1.5-inch needle should suffice for most cats, dogs under 10kg, and other small mammals.)

4.  If blood does not flow into the syringe naturally with heartbeats, draw back the syringe plunger, redirecting the needle until blood is located.

5.  As with all intraorgan euthanasia injections, begin injecting slowly then increase speed when certain the patient is unaware and free of pain.

This change in technique style came to me from two different situations around the same time. The first was observed in rabbits. The rabbits were placed in dorsal recumbency (belly facing upward) and the needle was inserted midline up towards the heart, just under the sternum. Blood flowed quickly and easily into the syringe. While effective, companion animals with owners present are always on their sides; they’re never euthanized on their backs. I suppose this could be done with the pet cradled in the client’s arms, however, this makes the needle and syringe more visible. The second time was at a few back-to-back CAETA euthanasia technique workshops where we practiced the procedure to see how effective it really was. Indeed, it was very straightforward. A few students have mentioned it to me over the years as well, but the long needle size in larger dogs made the approach less attractive.

Having performed this ventral intracardiac injection on my own patients for the past few months, I say with confidence that it works very well. It reduces the visibility of the needle on the topside of the chest wall (the lateral approach) and when properly placed, blood from the heart readily flows into the syringe (or extension set). The most important part is to use a needle long enough to reach the heart from this angle. Stock long needles with the rest of your supplies and you’ll be all set.

I hope this article will boost your confidence with intracardiac injections, so your clients have the option of being with their pet in their final moments, regardless of which technique you use. It’s all about creating a peaceful euthanasia experience.



Kogan LR, Cooney KA. Defining a “Good Death”: Exploring Veterinarians’ Perceptions of Companion Animal Euthanasia. Animals. 2023; 13(13):2117.

Cooney, K., Kogan, L. “How Pet Owners Define a ‘Good Death’: New Study Reveals Some Surprising Facts.” DVM360 magazine 2022. 53.8: 12

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Dr. Kathleen Cooney

DVM, CHPV, CPEV, DACAW resident Founder, Senior Director of Education for the Companion Animal Euthanasia Training Academy

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