Anesthesia Advances for Dogs and Cats
Posted by Kim Campbell Thornton on 10/16/2007 in General Articles
Managing pain in pets has always been a challenge because they can’t say where or how much they hurt. Up until 10 or 15 years ago, little was known about how animals experienced pain, and few drugs were available that could help. Of course, pets have always received anesthesia for surgeries, but beyond that not much was done about recognizing or treating any pain they might be feeling.
But thanks to owner concern about pain and anxiety, plus veterinarians’ own interest in animals, things have changed. New anesthesia techniques and medications help animals feel better and recover more quickly.
With their increased knowledge, veterinarians can use pain relief in new ways before (pre-emptive analgesia), during and after surgery. These include epidurals, constant rate infusion, and regional blocks.
Pre-emptive analgesia consists of treating pain before it happens by giving drugs that will last for several hours, well into the recovery period following surgery.
Drugs can also be delivered through an epidural, an injection into the epidural space of the spine. Epidurals help prevent pain in the abdomen and lower part of the body, so they’re especially beneficial for animals undergoing orthopedic procedures.
A technique called constant rate infusion (CRI) delivers an ongoing, constant-flow delivery of pain-relieving drugs over a period of time.
The CRI drugs target pain receptors in the spinal cord and brain, preventing pain signals from reaching the cortex, the brain’s central processing center. Each drug works on different receptors, producing a complementary effect. These very small doses, trickled into the body, block pain but don’t block physiologic functions such as breathing and heart activity.
If you’ve ever had a cavity filled – or worse, a root canal – you know what a regional block is—that shot of Novocain that numbs your face. Regional blocks, also known as nerve blocks or local blocks, obstruct the nerves that would otherwise carry pain signals to the brain, making them an important means of preventing pain in pets having surgery. Examples include the injection of local anesthetic along an incision line prior to surgery and facial blocks during dental procedures.
The way that general anesthesia is induced has changed as well. The most up-to-date method is intravenous injection of induction drugs, a more controlled way of putting a pet under anesthesia.
Advances in anesthesia techniques have made veterinary surgery relatively risk-free, but anesthetic care should be tailored to each individual animal to ensure a safe and comfortable anesthetic experience. Your veterinarian should have a plan for what things are especially important to monitor in addition to routine monitoring.
Before your pet undergoes surgery, ask your veterinarian:
Will my pet get a pre-anesthetic assessment?
Blood work to check kidney, liver and bone marrow function can identify abnormalities or infections that might make anesthesia a risk. That info can help your veterinarian make necessary anesthesia modifications to make it safer for your pet.
Will my pet have intravenous fluids while it’s anesthetized?
IV fluids help prevent dehydration and low blood pressure, which can be associated with anesthesia.
Will a qualified person be monitoring my pet’s vital signs?
Your veterinarian’s technician should be trained in the latest anesthesia and monitoring techniques, including monitoring blood pressure.
Will my pet’s blood pressure be monitored during surgery?
Blood pressure gives your veterinarian ongoing knowledge about your pet’s condition throughout surgery.
What emergency procedures and drugs are in place in the event of a complication?
These should include intravenous catheters placed so that drugs can be rapidly injected in the event of a reaction to anesthesia or a change in heart rate.
Will my pet be kept warm during and after surgery?
Cats and dogs can become cold during anesthesia and surgery, especially if they’re small or thin. Maintaining their body temperature not only keeps them comfortable, it helps ensure that the body does a better job of metabolizing pain drugs.
Although it was a long time coming, managing pain in animals is one of the defining issues of veterinary medicine in this new century. Because of it, animals recover more quickly, stay more comfortable, and regain their appetite sooner.
You can find more information about pain management at the web site of the International Veterinary Academy of Pain Management (ivapm.org).