Dr. Anna Dunton-Gallagher
OFF THE LEASH
Time and time again I hear reasons why people don’t want to have a dental cleaning/lump removed, etc. Sometimes this is cost-associated, but one of the biggest concerns I see among owners is putting their pet under anesthesia. People worry about this more in older pets. I am here to tell you about how anesthesia works at my hospital, and why a patient under anesthesia is as safe as possible.
For pet owners, anesthesia is not routine. It is a once-in-a-while occurrence that is usually associated with a procedure and larger-than-normal cost. For veterinarians and technicians, however, anesthesia happens very often. I will follow anesthesia from start to finish, exactly as it happens at my clinic when I am allowed to do everything. At times, cost issues will inhibit some of the things like blood work, but most of the things I will talk about are not variable. Even more important, most of it is exactly what happens when we have anesthesia ourselves.
Blood work and exam
Often these things are performed a couple of days or weeks before anesthesia, as they usually happen when we identify the problem that requires anesthesia. A complete physical exam lets us determine what needs to be addressed and any other issues. Heart and lung sound combined with palpation of all abdominal organs are the most important. For animals getting a routine procedure like a spay or dental cleaning that has been set up in advance, we may only see them the morning of. We always do a second complete exam right before any medication is given.
Blood work lets us see exactly how organs are functioning. Not every patient gets the same medications around surgery, we will tailor these to each patient based on blood work and exam results. Some blood-work changes may even make us hold off on doing surgery until we are able to investigate more.
After an exam the day of anesthesia, we then administer a pre-medication. The pre-medication serves many purposes. It helps relax animals and helps with pain control. We get a start on decreasing pain and inflammation before it even happens. We also take away any component of anxiety about being in the hospital. We typically place an IV (intravenous) catheter after the pre-medication so even that small amount of discomfort is reduced. We have many options for pre-medications, and the choice is based on each patient.
I take into account if their procedure will cause pain and how much. I use different medications and doses for an orthopedic procedure versus just simple anesthesia for a small-lump removal. I look at their organ function and any other issues (like seizures.) I consider their age and cardiovascular (heart) function. I also look at their level of anxiety. Each decision is based on all of these factors. The even better news? Medications are constantly being evaluated, and being in touch with specialized veterinary professionals and new studies help us always be up to date with the best care.
The medications of 20 years ago may have worked, but we have so much better information now. I have combinations of seven routine pre-medications that I use. I love studying pain medications and different anesthesia protocols, so I can always make very up-to-date choices for each individual patient.
An intravenous catheter is placed in a sterile site. This means they will have a little bit of hair clipped and the skin scrubbed. These catheters are placed for several reasons. We are able to provide fluids to the patient, which helps them metabolize anesthesia and keeps all organs functioning the same way they would if the patient was awake. Control over the amount of fluids they get helps us have an edge on controlling blood pressure, temperature and other anesthetic parameters.
While anesthetic complications are very rare, it is also good to have immediate access to a vein for injectable medications when needed. We continue fluid support until patients are awake, walking, and typically eating, after surgery. Since patients are fasted the morning of surgery (to help with any vomiting) we like to make sure their hydration and electrolytes are balanced.
After we inject a medication to put the patient under anesthesia (this also varies based on what is best for the patient) we place a tube into their trachea (ET, or endotracheal tube.) This tube delivers anesthetic gas and pure oxygen to the patient for surgery. This also protects the airway and keeps anything from the mouth (even saliva) from entering the lungs while their swallow reflex is inhibited.
Oddly, this is the part that most people with brachycephalic dogs (smoosh-faced, like pugs and bulldogs) worry about the most. This is odd, because these dogs love being intubated. They spend most of their life breathing room air (20 percent oxygen) through small nostrils and a small trachea (windpipe). Now they get to breathe 100 percent oxygen straight into their lungs. These dogs have never felt so oxygenated before! We leave the ET tubes in until they are wide, wide awake to protect their airway. Often these brachycephalic dogs will be awake and look at you and still don’t want their tubes removed.
Next week I will discuss what happens while patients are under anesthesia and during recovery.