Category Archives: surgery

Anesthesia

Anesthesia

I am frequently asked about the risks of anesthesia, especially for older pets. The conversation usually begins with, “Well, he’s too old for anesthesia, isn’t he?” Most often, the answer is no. We’ve come a long, long way from saying successful anesthesia means the patient woke up at all. With the current drugs and monitoring equipment available to us, we’re able to safely anesthetize patients. Age and medical problems do play a part on how we go about anesthesia, but it’s rare that either one totally prevents us from anesthetizing a patient.

This week, I’d like to walk you through the process of anesthetizing a patient.

Preoperative Consult

We usually discuss anesthesia as part of an appointment. If a procedure like a dental cleaning, tumor removal, spay or neuter is recommended, then anesthesia will be discussed with the client. We go over why anesthesia is necessary, then talk about what has to be done to prepare a patient to undergo the procedure.

Preoperative Diagnostics

The two things that we recommend for all patients undergoing anesthesia are bloodwork and an EKG. Bloodwork makes sure that organ function is good. The liver and kidneys are responsible for processing or getting rid of the anesthetic drugs, so we want to make sure they’re in working order. An EKG helps us screen for heart problems that might make anesthesia unsafe for a pet. The bloodwork is usually done about a week ahead of time. The EKG is done the day of the procedure.
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IV Catheter and Fluids

A
n IV catheter allows us to hook up IV fluids. Fluids help keep the blood pressure where it should be. Fluids also prevent dehydration and help flush anesthetic drugs out of a patient’s system. Keeping blood pressure normal is important to prevent damage to organs. Dehydration makes patients feel pretty terrible, so preventing that helps them feel better when they wake up. We place the IV catheter about an hour or two before the procedure.
IVCathPlacement 14

Premedication

One of the basic steps for practicing good anesthesia is to keep patients as low-stress and pain-free as possible. We begin the actual process of anesthesia by giving an injection of a mild tranquilizer and a fairly strong pain medication. These “premeds” keep patients calmer and stop pain before it starts. This allows us to use less of the actual anesthetic drugs, so the whole process is safer. Premeds are given intravenously or in a muscle.
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Induction & Intubation

Induction is the phase of anesthesia where we “knock the patient out” and place the endotracheal tube. The knockout drugs include propofol, dexmedetomidine, ketamine, and valium. Patients drift off to unconsciousness. We then open their mouth and slide a breathing tube (endotracheal tube) through the mouth, into the windpipe (trachea). The tube has a special inflatable balloon around it that makes sure the trachea is sealed off. This prevents anything from getting down into the lungs and makes sure that anesthetic gasses don’t come out into the surgery room. The tube is tied in place by a gauze strip that’s tied around the muzzle or the back of the patient’s head.
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Maintenance

Once the patient is induced and intubated, we hook the patient up to the gas anesthesia machine. This machine is hooked up to a pure oxygen supply. The oxygen flows through a special chamber that mixes in the anesthetic gas. This is breathed in by the patient through the endotracheal tube. The anesthetic agent goes into the bloodstream, then into the brain. It keeps the brain asleep. We have to adjust the amount of anesthetic gas depending on what the surgeon is doing. The goal of maintenance is to keep the patient asleep without making them too deep under the anesthetic.
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It takes a lot of training and experience to do this properly. Our licensed technicians are trained to perform these tasks safely. During maintenance, we have the patient hooked up to a monitor that shows us an EKG, blood pressure, temperature, oxygen levels, and breathing rate. The techs have their hands on the patient continuously. We record data for each of those measurements every 5 minutes. Between data recording points, the technicians are listening to the patient’s heartbeat and breath sounds with a stethoscope as well as checking pulses. They adjust the anesthetic depth based on how asleep the patient is.
Sxmonitor vetspecs 2

Recovery

Recovery from anesthesia is simply reversing these steps. When the surgeon is finished, the anesthetic gas is shut off. Patients then breathe pure oxygen for several minutes. When we are comfortable with them breathing on their own, we disconnect them from the pure oxygen and let them breathe normal room air. Patients slowly wake up. When they are conscious enough to be able to swallow, we remove the endotracheal tube. Patients are placed in a cage for close monitoring as they finish waking up. Most pets are awake and on their feet within an hour.

Summary & Questions

Following these steps carefully and with attention to individual patient needs lowers the risk of anesthesia even for very old or sick animals. I’m happy to answer questions that anyone has regarding the process of anesthesia. Don’t be shy! Thanks for reading!

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Filed under anesthesia, surgery

Why Spay?

I hope everyone has had a chance to be outside this weekend to enjoy the unseasonably warm weather! I’ve still got a gut feeling that we’re going to pay for this later with bad weather but I’m not about to miss a chance to enjoy it.

I still want to cover a topic today that I believe isn’t as well explained as it should be: spay surgery. I always welcome respectful debate about topics I cover, so I hope to encourage readers to ask questions or offer opinions. I have to manually approve each comment that’s made, so it may take a day for them to appear on the blog.

Commonly called a “spay,” this surgery is actually an ovariohysterectomy (OVH or OHE). It’s performed under general anesthesia with the obvious intention of preventing pregnancy in a female dog. Female dogs that are going to be used for breeding can’t be spayed, of course. If an owner is absolutely certain that a dog will be having a litter of puppies, there’s really no discussion to have. In the US, veterinarians remove both ovaries and almost all of the uterus from a female dog. In other parts of the world, the surgery may be only an ovariectomy, with just the two ovaries removed.

Most veterinary hospitals recommend that all female dogs get spayed. The age at which the surgery is performed is variable and ranges from 16 weeks to 6 months. The procedure is extremely routine for veterinarians. That’s a good thing! Procedures we do frequently have better outcomes and fewer complications. Patients are usually recovered by 10 days post-operatively. In most cases, I don’t think clients are given enough information about the procedure, why it’s important, and what to expect during and after the surgery. Clients are left with questions and anxiety. I can talk more about the procedure itself at another time if anyone is interested.

Population control is one of the most commonly cited reasons for spaying. The harsh truth is that far, far too many dogs are put to sleep in the US each year because they do not have homes. Most families are utterly unprepared for the amount of work (and cost) involved with having a litter of puppies, especially if the dog becomes pregnant against the owner’s intentions. Please don’t misunderstand. Population control is good! It’s a social and ethical goal that is sometimes hard for clients to connect with.

There are other direct health benefits from a spay. First of all, we eliminate the risk for cancer in the ovaries. Removal of the ovaries also stops the dogs from having heat cycles (estrus cycles). If the uterus is removed, we drastically reduce the risk of future uterine infections. If a female dog is spayed before her first heat cycle, we reduce her risk of developing mammary (breast) cancer by about 90%. If she is spayed after her first heat, we only reduce the risk by about 70%. That may not sound like much, but if it’s YOUR dog at higher risk, it’s risk that’s directly tied to you and your pet’s well being. I have lots of owners tell me that they “just want to have one litter,” then spay the dog. I also hear frequently, “We think it will be good for the kids to see our dog have a litter.” The vast majority of these clients never do breed the dog, which puts her at risk for the problems just mentioned.

Let me be clear: not spaying your female dog puts her at higher risk for two types of cancer and/or a life-threatening uterine infection. I don’t say this to use fear as a tool or a weapon. I think it’s critical that owners understand what the consequences of their choices are. In the last 5 months at Pet Authority, we’ve had at least 4 uterine infections and three mammary tumors. All of these dogs were unspayed females between 5 and 10 years of age. These are very real consequences that we see in practice.

In order to be fair, I need to mention some of the possible complications of the spay surgery. We do have to open the abdomen during this procedure, so complications with the incision (hernias, the incision opening up, etc.) can occur. These things are very rare if the post-operative rules are followed closely. Spayed dogs do have a lower metabolism than unspayed dogs, so they will not need as much food. (Spaying doesn’t make dogs fat. Overfeeding does.) Some female dogs will develop urinary incontinence at some point after the spay. We believe that this is related to the lack of hormones that the ovaries would normally release. This incontinence is treatable and in almost all cases and will be controlled as long as the dog stays on the incontinence medication.

Each owner needs to weigh the benefits, disadvantages, and costs associated with doing or not doing the spay procedure. Having an adult female dog spayed because she has a uterine infection more than doubles the cost of the surgery. It’s a higher-risk procedure because the dogs are already sick. I’m aware that a spay is not a cheap procedure. I wish we could make the surgery less costly without sacrificing patient safety. I also don’t believe owners would be comfortable hearing from us that we can do something at less cost with “only a little more risk.”

The bottom line, in my opinion, is that we can do a female dog a lot more good by spaying her than by not. We can minimize risk during anesthesia with good, safe practices. We can eliminate or reduce some cancer risks. We can nearly eliminate the chances of a life-threatening infection occurring. I just don’t see where the drawbacks are.

Thanks for taking the time to read my perspective on a somewhat controversial topic. Please ask questions, share information, or offer your opinion. Respectful debate is a healthy, beneficial thing. 🙂

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Filed under preventive care, surgery

Be Careful With the Internet — A Lesson in Bloat & Torsion (GDV) — CORRECTION 1/26/12!

I am issuing a correction after corresponding with one of the commenters on this post. She’s a fellow vet, and she astutely pointed out an error I made in interpreting the study abstract I used as the basis for some of the numbers.

I stated that the study found an increased risk of 20 and 52% with elevated bowls. The study’s abstract used these exact words:

“Approximately 20 and 52% of cases of GDV among the large breed and giant breed dogs, respectively, were attributed to having a raised feed bowl.”

‘Attributed’ seems to imply that elevation was the cause for GDV in 20 and 52% of the cases in those groups in the study.

Another source specifically stated that an increase in risk of 110% was found with elevated food bowls.

The bottom line, I believe, is as Dr. Leslie said. There are many factors, and we’re best able to help our dogs by addressing more than any single one. Putting too much emphasis on one factor as if it were the only cause or cure is not the best approach.

—–Original Post Below This Line——————————————————–

Now and then, a non-veterinary blog will post something concerning pets or veterinary medicine. I give these posts careful scrutiny when I come across them. I worry about readers getting poor advice. At best, it might mean small problems. At worst, it could cause death.

Two weeks ago, I read a post about ways to keep a pet’s food and water bowl area clean. It turns out that the post was originally written for a style and design blog based in New York City. The advice was:

…use an elevated feeding station to keep bowls in place and up off the floor. Elevated bowls aid in digestion and prevent strain on your pet’s back and neck. Place near a wall to prevent tipping.

This is very bad advice if you have a large or giant breed dog. Elevated food bowls were tied to an INCREASE in risk for a large or giant breed dog to develop bloat or bloat/torsion. This problem is also known as gastric dilation and volvulus (GDV).

Bloat simply means that the stomach undergoes rapid expansion with food and/or gas. It can get so big and so high-pressure that it starts to squeeze the other organs in the abdomen. While bloat alone can be dangerous for a dog, it’s generally not lethal.

Sometimes as a stomach is bloating, it flips in the abdomen. The stomach literally rotates, which twists the attachment at the esophagus and the outflow part at the duodenum. Once a stomach is twisted (volvulus), no gas can be burped or vomited out, so the stomach continues to bloat. Thi sis highly dangerous. Shock, organ damage, and death can occur rapidly.
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TThe dog’s head is far to the left off the xray, and the spine is at the top, running left to right. The big darker circle in the middle of the radiograph is the distended stomach. It’s full of gas. The pylorus of the stomach is seen at the top near the spine in those 2-3 very dark oblong shapes.

Dogs present in bad shape most of the time. The only way to fix GDV is to treat shock and then take the dog to surgery, untwist the stomach, and then deal with any of the many complications that come from the torsion. The risks of complications during and after surgery is often fairly high. Some complications are minor, but some can be lethal in and of themselves. GDV is a nasty, nasty problem. It’s extremely hard on the dogs and costly to handle.

When I read that tip, I was horrified. I emailed the original authors. They told me they would issue a correction on the blog. Three days later, the correction went up and the post was removed from the authors’ main blog. The site that I read it on first has not been corrected.

The study I cited recruited 1,637 dogs. Owners were contacted yearly to see how many had developed GDV. Several factors were considered for increased risk. The results showed a 20% increase in large breed dogs and a 52% increase in giant breed dogs with elevated bowls. That’s a huge increase in risk!

Body shape/size, temperament, and breed may play a part in developing GDV. We can’t affect those factors. We can lower risk with meal frequency, meal size, time of exercise, food/water bowls. Dogs should have 2-3 smaller meals spread out across the day instead of one big one. Exercise should be avoided for a few hours after a meal. We certainly should NOT elevate food and water bowls.

Today’s moral: be careful what you read and check with your vet!

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Filed under internet, practice, surgery