What questions should be asked before you agree to anesthesia?

1. Is anesthesia really necessary for this procedure? Look for a veterinarian who is willing to work with you on this. Some procedures CAN be done in the awake patient. With a local anesthetic, some wounds can be sutured, a skin biopsy taken, small tumors removed. OFA films can be done in awake dogs, but the dog must be cooperative enough to lie on his back with his hind legs stretched all the way out and rotated in. And he must be STILL. Some dogs just won't go for this without sedation.

2. What kind of preanesthetic screening is done? At a minimum, in a healthy young dog, a physical exam should be done, along with a history of the dog's general health, recent medications, drug allergies, vaccinations and any recent insecticide exposure. Depending on the dog's age and history, blood work may be necessary before anesthesia.

3. Have you done anesthesia on Belgians before? While there is no definitive proof that Belgians as a breed are more sensitive to anesthesia, there is certainly enough anecdotal evidence to make us very cautious. Belgians, as a breed, tend to be lean, active dogs with little body fat. This combination of traits may make them susceptible to relative overdoses, if the anesthetic is given strictly by body weight or given too quickly without letting the dog settle down. In other words, a thin dog that will fight going under, may need a lower dose than he seems to!

4. What kind of anesthetic will be used? There are many different drugs that may be safely used for anesthesia, and the selection is subject to each individual veterinarians experiences and preferences.

COMMONLY-USED DRUGS

Keeping in mind that new, better drugs are coming along all the time, here is a list of some of the drugs that are commonly used in the average practice.

ATROPINE (or GLYCOPYRROLATE)

These drugs are used as preanesthetics to prevent the heart from slowing down during anesthesia and to dry up the excess saliva that sometimes results with anesthesia. Atropine should not be given to an animal with signs of congestive heart failure.

ACEPROMAZINE

Commonly called ACE, this drug is often used in pill form for dogs that have storm anxiety or car sickness. It is used as a preanesthetic to sedate the patient, control nausea, and to protect against some heart arrhythmia. Ace dilates the blood vessels so it may lead to lowered body temperatures which slow recovery. This drug also lowers the blood pressure and the seizure threshold. THIS DRUG SHOULD NOT BE USED IN EPILEPTICS OR PATIENTS IN SHOCK.

It has been suggested that the manufacturer's dose be reduced by 50% or more when used as a preanesthetic. It should also be used with extreme caution in older dogs, neonates and dogs with liver problems.

BARBITURATES (Pentobarbital, Nembutal, Thiopental, Pentothal, Thiamylal, Biotal, Surital, Brevital)

These drugs are given intravenously to allow intubation. During intubation, a tube is inserted into the windpipe so that the patient is ensured of a clear airway. Oxygen and anesthetic gas are then given through the tube.

Respiratory depression can be a problem with this class of drugs, the dog may even stop breathing on its own when they are first administered. It is CRUCIAL that dogs on this kind of anesthesia have an endotracheal tube in and be on oxygen, so that they can be ventilated if need be.

Barbiturates may also cause a decline in heart function and blood pressure immediately after injection. They can also cause irregular heartbeats and even cardiac arrest, especially if the patient is stressed or excited. If these drugs accidentally get outside the vein during injection, they can cause tissue damage.

Animals awake from barbiturate anesthesia when the drug leaves the brain and disperses into the body fat. Over time, the drug exits the body by way of the liver and kidneys. So thin animals, and those with liver or kidney problems, may have prolonged recoveries. Sighthounds have a proven increased sensitivity to these drugs, because they are very low in body fat and their livers have some problems processing barbiturates. I, personally, don't use Barbiturates anymore.

This gas anesthetic is commonly used today, and although it is expensive, its wide margin of safety compared to the older Metophane and Halothane, make it the drug of choice for most patients. Because 99% of Isoflurane leaves the body through breathing, animals begin to wake up almost as soon as the gas is turned off. Isoflurane doesn't depress the heart and doesn't have to be stored in the fat or processed by the liver or kidneys.

DOMITOR (Medetomidine)

Domitor is a sedative analgesic drug which is useful for short procedures like taking X-rays or minor surgery. It should not be used in patients with heart, liver, or kidney disease nor in dogs that are very debilitated or in shock. It doesn't always work well (sometimes not at all!) in dogs that are very stressed or agitated. It works best if you give it and then put the dog in a quiet, dark place to get sleepy.

Adverse effects can include slow heart rate and breathing, excitation rather than sedation, vomiting, and recurrence of sedation after recovery.

While it can be given intravenously, I prefer to use the intramuscular route only. The big advantage of this drug is that it can be reversed with Antisedan so that when the procedure is done the dog can be up and near normal in a very short time. I've used this drug for quite a few Belgians and it has worked well for doing OFA films.

KETAMINE (KETASET) Ketamine has a wide margin of safety when used for anesthesia. Given along with Valium, Ketamine gives a quick, smooth induction in about 1 minute. Ketamine does not depress the heart rate, and while some animals seem to hold their breath, their oxygen levels usually remain adequate.

KETAMINE SHOULD NOT BE USED IN EPILEPTIC DOGS.

Rough recoveries with thrashing and screaming can sometimes be a problem with Ketamine, so patients should be carefully monitored. This excitement generally lasts only a few minutes. Recovery from Ketamine and Valium anesthesia usually occurs in 2-6 hours in young, healthy animals. 

KETAMINE(Xylazine) Rompun is a potent sedative and muscle relaxer. It is also associated with a "higher incidence of anesthetic complications and death than any other commonly used preanesthetic" (1) It is often combined with Ketamine for general anesthesia.

The advantage to Rompun is that it can be given in the muscle, and occasionally, a patient is so intractable that hitting a vein or masking down is not an option. Also, the drug Yohimbine can be given to reverse the effects of Rompun.

Rompun slows the heart and may cause irregular heartbeats and low blood pressure. It may cause greatly depressed breathing, gastric bloating, vomiting, prolonged deep sleep. This drug should not be used in dogs with heart, lung, liver or kidney problems, and I have serious reservations about its use in any patient.

PROPOFOL (Rapinovet)

This sedative-hypnotic drug has now become the "drug of choice" in many practices. Propofol can be used alone for short procedures or as an induction agent before gas anesthesia. A single dose last only about 5 to 7 minutes as this drug is rapidly eliminated from the body. It does not accumulate in the tissues so it is safe to repeat doses. Animals generally recover smoothly and are normal very quickly without evidence of a "drug hangover". Propofol's rapid elimination makes it safe even for animals with liver disease. It can be used without fear of triggering seizures in epileptic patients.

Propofol can depress heart function and breathing, though it does not cause cardiac arrhythmia. And endotracheal tube should be in place in case ventilation is needed. If given too rapidly or at too high a dose this drug can cause respiratory arrest. There has been a study showing prolonged recoveries in Greyhounds (47 minutes as opposed to 7 minutes in mixed breeds) but I have not seen this reported in Belgians.

SERVOFLURANE

This inhalation anesthetic is very similar to Isoflurane. It is quickly expelled from the body just by breathing so it's very safe, even for elderly or ill animals. Recovery times are reportedly even quicker than those with Isoflurane.

VALIUM (Diazepam) This drug is usually used together with Ketamine. Valium calms the patients, helps prevent seizures, and relaxes the skeletal muscles. Valium is one of the safest of preanesthetics, and while it must be used with caution in patients with liver problems, it is very useful for anesthesia in the elderly or high-risk patient.

XYLAZINE (Rompun)

Xylazine is a potent sedative and muscle relaxer. It is also associated with a "higher incidence of anesthetic complications and death than any other commonly used preanesthetic". It is often combined with Ketamine for general anesthesia.

The advantage to Rompun is that it can be given in the muscle, and occasionally, a patient is so intractable that hitting a vein or masking down is not an option. Also, the drug Yohimbine can be given to reverse the effects of Rompun.

Rompun slows the heart and may cause irregular heartbeats and low blood pressure. It may cause greatly depressed breathing, gastric bloating, and vomiting, prolonged deep sleep. This drug should not be used in dogs with heart, lung, liver or kidney problems, and I have serious reservations about its use in any patient. EVER.

So how can you do your best to insure a safe anesthetic for you Belgian?

Look for a veterinarian who is willing to do procedures without anesthesia if possible and who does appropriate preanesthetic screening. While it may prove difficult to find a veterinarian who has much experience with Belgians, look for someone who will listen seriously to your concerns and tell them that Belgians seem to handle anesthesia much like sighthounds.

As far as which anesthetic is used each patient must be evaluated individually. In my experience, (15 years) the safest way to induce anesthesia for the majority of patients is to give Valium and Ketamine intravenously, intubate the dog, and maintain it on Isoflurane. An alternative, especially for the sick or elderly patient, is to mask the dog down with Isoflurane, and then intubate and maintain on Iso.

I've used the Valium, Ketamine, Isoflurane combination on my own Belgian, my elderly, diabetic Sheltie who has kidney failure, on a 14 year old who had heart failure, kidney failure and a huge infected uterus--in fact, I use this combination of anesthetic for 99% of the procedures I do.

Anesthesia is a state of controlled and reversible unconsciousness, and while nothing can make it 100% safe for every patient, you and your veterinarian can work together to make it the safest experience possible.

by Libbye Miller DVM (reprinted with permission)

Allow me to share a few basic facts of anesthesia. Although I usually work with human children there are several principles that carry over to the veterinary practice.

First, there are no SAFE anesthetic agents. All agents are potentially toxic, suppressive, poisonous, etc, whatever you wish to call it. Unconsciousness is not a natural state. Whatever produces unconsciousness is potentially deadly. 

More important than which agent being used is the anesthetist's experience with that agent. By this I mean his or her knowledge of what can be expected to happen with the agents being used. Certain agents may be preferred for certain species or certain situations (or ages of humans), but the final result bears more upon the care with which an agent is administered than which agent is chosen. Several of my professors would say that a good anesthetic could be given with airplane glue (not that I never saw it tried...) if one was appropriately careful. Again, there are NO safe anesthetic agents, be they isoflurane, halothane, ether, ACE, xylazine, narcotics, Valium, midazolam (Versed), ketamine, barbiturates, propofol, etc. Furthermore, despite producing unconsciousness, some of these are only hypnotics and not truly anesthetics,...but that's another discussion.

Sedation is NOT safer than general anesthesia. Very few procedures can be done under sedation alone without inducing unconsciousness. The risks and complications of sedation are the same as for general anesthesia. Thus, unconscious patients are essentially under general anesthesia. Most sedative agents require larger doses comparatively than anesthetic agents and the overall duration is much longer. Anesthetic agents are generally quicker to emerge or recover from than the necessarily larger (and longer acting) doses of sedative agents. Sedated patients should be monitored just as closely as anesthetized patients, but too often are not. When serious problems occur during sedation it is invariably due to a lack of monitoring, which leads to the next point. 

Monitoring is the key to safety. One cannot alter an anesthetic agent or resuscitate the patient unless one knows what is happening to the patient, veterinary or human. The reality is that monitoring is available (and mandated) for humans, but much less available for animals, outside veterinary research institutions. Monitors are expensive (about $100,000 per human anesthesia work station--including the anesthesia machine), and time consuming to learn and set up. Without electronic monitors one is left with a finger on the pulse, the sound of the heart and lungs, and the color of the blood. These are still pretty reliable for the practiced anesthetist. 

The anesthetist, however, must know what's going on with the patient. In the medical center, it is the ONLY responsibility of the anesthetist to pay attention to the patient, while the surgical team (several individuals) concerns themselves solely with the operation. In the veterinary office, the surgeon may be both the anesthetist and the operator. She/he may or may not have an assistant--but an assistant is primarily there to help with the surgery. One can only direct one's attention to so many things at one time. For an operator, when attention is commanded by the operative procedure, the anesthetic must come secondarily. Usually, much more often than not, it goes well. Human anesthetic mortality is about 1:50,000 to 1:100,000 anesthetics--as low as we can get it at the current state-of-the-art. It is higher in veterinary practice. Standards of care are different.

I am in the same boat as the rest of you when it comes to having my dogs anesthetized. (Three times so far for my 3 yo BSD.) I worry also. My vet will not permit my presence during operative procedures--and I'd probably be a nervous wreck if I were there. I'd be missing all the monitors that I'm used to seeing in the OR. 

Most of us do not have the luxury of an expert veterinary anesthesiologist or a veterinary college nearby. My vet has no other Belgians in his practice. Many vets will never have cared for a Belgian before yours. Perhaps the best advice I've had is to be sure that your vet understands that Belgians (of all varieties or breeds) need to be treated as SIGHT HOUNDS. That is, they have a relatively high muscle mass in relation to their weight, low body fat, and the anesthetic should be conducted accordingly. It does little good to specify a particular agent for your dog, since the success lies not with the agent, but with the anesthetist. I wouldn't want my vet to use any specific agent for the first time ever on my dog just because I insisted on it. 

Veterinary anesthetics are not trivial events. (Human anesthetics are much safer.) Avoid them for your dog whenever possible. When an operation/anesthetic is necessary, remind your vet of the reputation Belgians have for anesthesia. Express your concerns. Ask what can be done for your dogs protection. In effect you are asking your vet to "please be extra careful." In the end, you've got to trust your vet. If you don't, then find another vet. Hopefully you will find a vet that you can trust before your dog needs a procedure. Unfortunately there are no guarantees.

Finally, I don't understand why our Belgians are "sensitive" to anesthesia. The word "sensitive" is nonspecific and conveys no useful information beyond "be extra careful". The parallel situation does not occur in humans adults or children. All humans seem to require agents within a fairly predictable dosage range, unless significant disease is present within one or another organ system. Significant disease does not seem to have been present in those Belgians lost during anesthesia. The deaths do not seem to have been the result of idiosyncratic reactions, allergies, or metabolic crisis precipitated by anesthesia. Any further information and any details would be personally welcomed. Please post me privately.

Respectfully submitted,

Jack

Michael J. Kibelbek, M.D
Cincinnati Children's Hospital Medical Center
Cincinnati, OH 45229

michael.kibelbek@cchmc.org