The finer points: Injecting common sense into your regional anesthesia strategy
I’ve always been afraid of doing local blocks for some reason—probably because I just never really got comfortable with them. So they usually aren’t top of my mind in practice until somebody says, “We can do a local block.” And I think to myself, “Well, duh! Why didn’t I think of that?”
Realizing my severe lack of local-block knowledge, I hightailed it to the lecture “Regional anesthesia: Minimize pain; maximize profit and efficiency” at a recent Fetch dvm360 conference. This was a Full Circle session, covering the clinical details (led by Mike Barletta, DVM, MS, PhD, DACVAA), application to the business side of practice (led by Ori Scislowicz, BS, LVT) and how to best leverage the team (led by Tasha McNerney, BS, CVT, CVPP, VTS [anesthesia and analgesia]).
Here are some of my key takeaways—I can’t wait to practice them in clinics!
Testicular blocks will make your neuters go more smoothly and can help reduce the use of systemic drugs, says Dr. Barletta.
I tried this once and had so much bleeding I vowed to never do it again because I was convinced the lidocaine was making this dog bleed like a hemophiliac on speed. I ended up sending him to the emergency room for “observation.” Yeah, so, I never used a testicular block again.
Then I realized I’d done it wrong. My mistake? I’d dripped the lidocaine into the incision site postneuter, happily thinking I was doing this dog a favor. According to the Fetch dvm360 experts, it’s much more effective to use the lidocaine preneuter, injecting it directly into the testicle, and not to use it after you’ve already taken the testicles out!
Lidocaine does cause vasodilation and can increase bleeding; however, used appropriately, it will make your neuter go much more smoothly and cause your patient to feel less to no pain. You don’t have to use a long-acting agent here, such as bupivacaine—most of your local anesthetic will end up in the trash when the testicles are discarded, McNerney says.
Sacrococcygeal blocks will make your life much easier when it comes to blocked toms, tail amputations, and basically any surgery you’re doing in the urogenital and perineal regions, says the Fetch dvm360 team. According to Dr. Barletta, the beauty of this block compared with an epidural is that your patient will retain its ability to walk immediately after the procedure.
McNerney singlehandedly convinced me to try this the next time I encounter a blocked tom that proves difficult to catheterize. “Instead of wrestling with the penis until it becomes a swollen, bloody mess, just sacrococcygeal-block that baby,” she says. “The penis pops right out.”
She also says to Instagram-story her when that happens and she’ll do a happy dance for you. It’s a win-win-win situation. You win, the cat wins and McNerney wins.
What not to do
As I realized when I used lidocaine after a neuter, there are definite no-nos when it comes to local nerve blocks. Here are a couple:
1. Thou shalt not mix two anesthetic agents. For example, don’t mix bupivacaine and lidocaine in hopes of achieving a middle ground in terms of speed of onset and duration of effect. They don’t work that way, Dr. Barletta says—you’ll end up with an in-between onset and duration, deriving the benefits of neither. It’s better to use anesthetics sequentially when necessary: first a fast-acting agent, followed by a longer-lasting one—for example, at the end of the procedure for more postoperative analgesia.
2. Thou shalt not use epinephrine mixed with a local anesthetic on terminal blood supply areas. For example, don’t use epinephrine on the tail area or ears because it causes vasoconstriction, and you may cause ischemic necrosis of the area because you cut off the blood supply for too long.
An eternal conundrum
Last but not least, I leave you with the eternal sodium bicarbonate conundrum: to mix or not to mix? The Fetch dvm360 experts say yes, it’s OK to mix sodium bicarb with your anesthetic to decrease the sting of a local block. However—and this is a big however—some local anesthetics precipitate out when mixed with sodium bicarb, so it’s important to know which ones! Commit them to memory—they are bupivacaine and etidocaine.
With these tips blended together from the minds of a talented trio of experts, I am now ready to incorporate nerve blocks into my regular practice. Join me?