VetInfo Digest
November 2003
Table of Contents:
Before Anesthesia
Presurgical Lab Work
During Anesthesia
After Anesthesia
Monthly Note:
In order to practice veterinary medicine it is necessary to accept the risk of producing anesthesia in a patient. Much of what we do would simply be impossible without the ability to perform surgery without pain and without patient movement. Despite this, I don't think that I will ever be completely comfortable when I have a patient under anesthesia.
Clients sometimes assume that I won't understand their worries about anesthesia, especially clients who have experienced an anesthetic death among their pets. I understand this worry to a greater degree than some veterinarians, though. During my lifetime I have experienced the anesthetic related death of two pets, both very dear to me. The hurt at the time was tough. The nagging feeling that it shouldn't have happened doesn't ever completely disappear. I'd like to say that experiencing this the first time with Duchess made me so cautious about anesthesia that I was able to successfully avoid causing any anesthetic deaths. Unfortunately, that isn't the case. I was the veterinarian when Hank died. I understand why anesthesia is necessary and how much good it does. I understand the risks associated with anesthesia, as well. Anesthesia will never be completely safe but it can be made more safe when proper preparations are made for its use. Its the best we can do.
Before Anesthesia - The importance of the physical examination
A physical examination of the patient is an essential procedure prior to inducing anesthesia. The patient's physical state is an extremely important variable in anesthetic safety. Patients with preexisting respiratory distress and detectable heart conditions are obvious anesthetic risks. More subtle risks that can often be detected during a physical examination include skin disease, gastrointestinal disease, obesity, poor circulatory function and evidence of hormonal disorders. These problems can also impact the outcome of an anesthetic procedure. If you take your pet to the same veterinarian most of the time, your vet is likely to be aware of the physical problems peculiar to your pet. Even with this in mind, a physical examination prior to anesthesia is best. If your pet is facing surgery when the veterinary surgeon is unfamiliar with him or her, the importance of physical examination can not be overstated. A significant percentage of anesthetic complications are due to preexisting health problems that were undetected when anesthesia was induced.
If the surgical procedure is elective, it makes a great deal of sense to schedule a consultation visit, including a physical examination of your pet, prior to the surgery. If this is not possible, at least try to stick around at the surgical facility long enough to ensure that someone actually does a physical examination of your pet prior to the surgical procedure, if that is possible.
An accurate weight measurement is necessary for most forms of anesthesia, with the possible exception of pets who are anesthetized by use of an anesthetic gas administered as both the anesthetic induction agent and the anesthetic maintenance agent. Gas anesthesia regulation is not weight based for the most part, although there are some equipment changes that are necessary for dogs and cats weighing less than 10 to 20 pounds.
Before Anesthesia - The Importance of the Patient History
There are a number of questions that should be asked when planning an anesthetic procedure. It is very easy to overlook some of these questions or to assume that the medical history of a pet who comes to a veterinary hospital on a regular basis is so well known that it isn't necessary to ask these questions. I know that we make this assumption in our practice more than we should. For this reason, I'm going to include a suggested list of questions and explain why it is important to know the answers to them.
Is your pet on any medications? This includes aspirin, cough medicine and all other over-the-counter medications. If you are giving your pet any medication on a regular basis tell your veterinarian prior to the anesthetic procedure. In most cases this won't matter but it can be extremely important if the medication interferes with a particular anesthetic agent or causes blood clotting problems, like aspirin does. If you gave any medications in the last day or so, even if these are not medications you commonly use, it is important to tell your vet that, as well.
Does your pet have any breathing problems, including shortness of breath after exertion? Pets who tire readily may have heart disease or respiratory disease. Both of these impact on the success of anesthetic procedures.
Does your pet have a history of any preexisting disease? While it isn't necessary to tell your vet about every disease that has occurred in your pet's lifetime, it is a good idea to talk about any past liver disease, kidney disease or heart disease. If your pet has a history of seizure activity this is important, too. One of the most commonly used preanesthetic agents (acepromazine) can lower seizure thresholds and this can lead to seizure activity in a patient prone to this problem. In addition, it is important to mention any current problems with skin disease, diarrhea, vomiting, or blood loss.
Has your pet had reactions to vaccinations, medications or prior anesthetic procedures? It makes sense to avoid giving a pet a medication that caused problems in the past, especially when that pet may be asleep and not showing typical signs of a reaction to the medication. This is also an important issue when vaccinations are given during an anesthetic procedure.
In general we try to avoid giving vaccinations to anesthetized pets but once in a while this a virtual necessity. When it is, we try to be sure vaccines haven't caused problems in the past as it can be easy to overlook a vaccine reaction in an anesthetized patient. When I was in veterinary school an anesthetized patient was given penicillin intravenously and died from the penicillin reaction because it wasn't recognized as the cause of the anesthesia problems.
While it is important to know if a pet had problems during previous anesthetic procedures, it is not always a reason to avoid using the same anesthetics. In truth, most anesthetic complications are the result of human error at some stage in the anesthetic planning or procedure and not due to the agent itself. There are definitely exceptions to this rule so caution is advisable whenever it seems necessary to use an anesthetic agent that caused problems in the past but previous problems may not rule out the use of a particular anesthetic agent. Obviously the knowledge that a pet had problems in the past does give the anesthetist reason to be a little extra vigilant, though. If a good alternative anesthetic procedure is available there is no reason not to use it as a precaution.
Pet owners often have heard that their pet's breed is more susceptible to anesthetic complications than other breeds. As far as I can tell in researching this topic and in reviewing the complications of anesthesia in our practice, this is true in a limited number of cases. Greyhounds and to some extent other sighthounds are more sensitive to barbituate anesthetics. Logically they may also be more sensitive to propofol (Propoflo Rx), as well, as both are cleared rapidly from the bloodstream by being absorbed into fatty tissues, which these breeds often have less of than most dog breeds. Dogs and cats with short noses or flattened faces are more likely to have problems during anesthetic induction and recovery due to soft palate obstructions. Almost all veterinarians are aware of the problems in these breeds. In general, except for these two known problems, the suspected sensitivity to anesthesia in breeds is more likely to be rumor than fact.
If you know of any condition that might affect your pet's ability to tolerate anesthesia you should write it down on a note and ask that the note be kept with the pet's records on the day of surgery.
What Does a Presurgical Laboratory Panel Tell You?
Veterinarians frequently recommend obtaining a blood sample and doing a "pre-surgical" blood panel prior to surgery. Clients sometimes view this as almost a guarantee that their pet will not have adverse effects from anesthesia or the surgical procedure itself. This is simply not true. So why do veterinarians often insist on this procedure?
When veterinary anesthesiologists are asked what the minimal amount of blood work they are comfortable with prior to an anesthetic procedure is, most will say a total protein measurement and packed cell volume measurement. The packed cell volume (PCV) is also called the hematocrit (HCT). It is the percentage of the blood that is comprised of red blood cells. Originally, this was measured by putting whole blood in a centrifuge and spinning it so that the cells settle to the bottom of the measuring tube. The tube was then held against a chart that allowed the percentage that is occupied by blood cells to be measured. While this procedure is still used there are several more modern ways to determine the hematocrit. The PCV or HCT can also be estimated by multiplying the hemoglobin content of the blood by three. In some situations it is easier to measure the hemoglobin, so this measurement is sometimes substituted for the PCV or hematocrit.
Anesthetists want to know these numbers because the PCV allows some estimation of the oxygen carrying capacity of the blood and because the total protein level allows an estimation of the carrying capacity of the blood stream for anesthetic agents and the general health of the circulatory system. These are the really critical issues in delivering anesthetic agents safely. If these values are normal and the clinical history of the patient is normal, the odds of an anesthetic problem are very low.
A packed cell volume of at least 28 in dogs and at least 26 in cats is necessary for a surgical procedure to have minimal risk associated with preexisting anemia. Optimally, the PCV should be above 33 in a dog and above 30 in a cat prior to a surgical procedure. It is possible to do surgery when the packed cell volume is much lower in urgent situations, especially when the anesthetist is experienced or when blood can be administered, but the risk to the patient increases when the PCV drops below these values.
If the total protein level is below 5 it is best to check an albumin level. Albumin is the protein that is actually responsible for transporting some anesthetic agents and maintaining proper osmotic pressure in the blood stream. In general, albumin represents about half the total protein in the vascular system. Albumin levels less than 2.5 require some adjustment in both anesthetic and surgical plans. Albumin levels below 1.5 can be life threatening and it is best to avoid all surgical procedures that are not absolutely necessary when the albumin is this low. It is also important to consider that rapid strong healing of surgical wounds may not be possible when albumin levels are this low. The two organs most affected by low protein levels in the blood stream are the lungs and the brain so it is fairly obvious why anesthetists worry about this protein level.
When veterinary anesthetists are asked what the optimal presurgical workup is, they tend to agree on some things and disagree widely on others. Pretty much without question the number one thing that anesthesiologists recommend prior to surgical procedures is a good physical examination first and laboratory work up as a definite second choice. Despite this, it is obvious that a small number of patients with preexisting problems are identified through preanesthetic lab work. Since no veterinarian really wants to have to explain that a pet died from unforeseen complications there is a strong impulse among veterinary practitioners to be as cautious as possible. It isn't necessarily a cost effective approach when looking at veterinary costs overall, but many people do consider their pet priceless. If so, taking every possible precaution makes sense.
Pre-anesthetic Laboratory Panels
In reviewing records from other veterinary hospitals and looking back at our records over the years it is evident that there are a great many variations in the recommendations for laboratory work-ups prior to anesthesia. I think that the most common recommendation is probably a "mini-panel", consisting of complete blood count (CBC) and a small number of blood chemistry tests that are useful in evaluating liver damage, kidney function and blood sugar levels. The CBC includes an hematocrit evaluation but provides some additional information on red blood cell health. The white blood cell count helps to rule out preexisting infections, immune system disorders and cancers. Evaluation of kidney and liver related chemistry tests helps to ensure that these organs are functioning well enough to handle the extra workload associated with anesthesia. Hypoglycemia is a fairly rare condition but can cause problems with anesthesia if it is present. Diabetes is more common in middle-aged and older dogs and also is a factor in anesthetic planning.
Some veterinarians think that it is better to run a more complete laboratory workup prior to surgery. Clients sometimes think of this as just a way to increase the fee associated with anesthesia and surgery. I think that this is probably true in some cases but that they are the exception. I have spoken with and even argued with enough veterinarians over the necessity of pre-anesthetic lab work to get a sense that many veterinarians who insist on complete presurgical laboratory panels are quite sincere in their perception of the benefits of extensive lab work. It is easier to understand this if you imagine having to tell a pet owner that their pet died during an anesthetic procedure because of liver damage that might have been detected through blood testing.
This isn't just an issue that affects veterinary patients. If you have had surgery more than once it is probably apparent to you that physicians also vary widely in how they feel about the necessity for laboratory workups prior to surgery. There have been cost/benefit analyses of presurgical laboratory work in humans. In general, it is recognized that preanethestic lab profiles above the minimum recommendations rarely impact on the success of anesthetic procedure. The problem here is where to draw the line. If preanesthetic laboratory work shows a significant impediment to anesthesia in 1 in 10,000 patients, does that justify doing lab work on the other 9,999? The answer mostly depends on your own innate sensitivity to risk. Those odds are good enough that it is easy to argue that extensive lab testing is economically unjustified -- except that many people put such a high value on the one life that might be lost that there is no amount of money saved that justifies any risk, to them.
A different way of looking at this is to ask what happens when a surgery is necessary but preanesthetic lab work does reveal a preexisting problem that might threaten the pet's life if surgery is performed. Finding a patient with some level of elevation in kidney or liver related laboratory test values is not unusual when large numbers of patients are tested. I have been involved in a number of cases in which necessary treatments were being delayed or even abandoned due to the findings of preanesthetic laboratory work. I know that in several of these cases the health risk to the pet from not having a necessary surgical or dental procedure was far higher than the risk to the patient of elevations in ALT or BUN values in the lab work.
Urinalysis is sometimes recommended as a presurgical test in addition to, or even in place of, blood testing. It is possible to assess the kidney function reasonably well from a urinalysis if the specific gravity of the urine is high enough. When the kidneys are functioning their job is to concentrate the urine which raises the specific gravity. If the kidneys are doing this, they have the ability to function. If there is no sugar in the urine diabetes is ruled out, as well. High bilirubin levels would indicate a need to look for internal bleeding or liver damage.
It is critical to understand that finding any unwelcome changes in the lab work doesn't automatically mean stopping there and not performing the planned procedure. It may mean making adjustments in the type of anesthetic event planned, such as changing anesthetic drugs or adding specific fluid therapy to help a patient with preexisting problems make it through an anesthetic procedure safely. Often the worst mistake that can be made is to find a problem on lab work and then get so wrapped up in it that the needs of the whole patient are ignored. If you think of preanesthetic lab work as a tool for planning a safer anesthetic procedure rather than as a tool for making a "do or don't do anesthesia" decision, you have a better idea of the real value of the lab work.
In addition to standard complete blood counts and serum chemistry profiles, there are times when it is a good idea to think about more specific laboratory testing but most of these tests will be based on physical findings at the time of the preanesthetic examination. Some examples of specific testing that can be meaningful include feline leukemia tests, thyroid function tests to rule out hyperthyroidism in cats and hypothyroidism in dogs, heartworm testing and blood gas analysis.
The blood gas values are usually measured when trauma is the initiating cause of surgery as changes in the these levels are a strong indicator of shock and can give some idea of the extent of tissue damage that might be encountered. These levels may have to be monitored during surgery in trauma patients and patients undergoing long or difficult surgical procedures, as well.
Electrolyte levels can indicate the presence of hypoadrenocorticism (Addison's disease) and it is reasonable to check these levels prior to anesthesia when a puppy is not growing well, has minor but persistent symptoms of gastrointestinal disease or seems lethargic. Electrolyte levels are also important in trauma cases and testing for them is often combined with testing for blood gas levels in trauma patients.
Some veterinarians insist on heartworm testing prior to surgery. Heartworm disease has a relatively minor impact on surgical procedures unless clinical signs of the disease are present, but knowing the heartworm status of a patient, if it is unknown, is a good idea. I really believe that this testing is unnecessary for patients who are on heartworm prevention medications and have been tested negative within the last year to two years, though.
Perhaps the most important point about preanesthetic lab work, if it is run, is to make sure that someone actually looks at the results prior to the surgical or anesthetic procedure. I remember looking over the bill for a surgery my mother had and seeing the results of her presurgical lab work at the same time. The surgery had been on a Monday and the lab results were reported on Tuesday --- making me think that it was unlikely anyone saw them prior to the surgery!
The anesthetic procedure:
There are probably hundreds of anesthetic combinations available for use by veterinarians. This causes constant controversy over which anesthetic is best. The problem with this is that the definition of best varies a lot, depending on the emphasis of the person who is making the evaluation. If an anesthetic agent was developed that would keep a patient perfectly still and which caused no deaths, but which also provided no pain relief, would it be better than an anesthetic agent that provided excellent pain relief, kept the patient still enough for surgery but had a 0.5% death rate? The difference in these two examples is what makes anesthetics so controversial. Anesthetics that provide very good pain relief are also often the ones that have higher risks associated with them. If a veterinarian chooses to provide poor quality pain relief in exchange for a better chance to have a live patient is that a good choice? I think that most people would choose better pain relief for themselves given this choice and knowing the risk. If that is the case, then people should make the same choice for their pets.
There are several phases to the anesthetic procedure. The first phase is preparation for the anesthetic and surgical event. This will vary depending on the procedure contemplated and the patient's needs. A dental cleaning probably won't require pain relief medication be given prior to the procedure. Extraction of a tooth does call for administration of a pain killing medication prior to inducing anesthesia, so that it will have some effect while the patient is waking up. It takes some time for pain relievers to work well. For this reason, nonsteroidal anti-inflammatory medications should be given about 2 hours prior to surgery and narcotic pain relievers, such as morphine, should be given at least 30 minutes prior to the procedure. A small dose of a sedative can make it easier for the pet to fall asleep, enable less anesthetic use and smooth the recovery from anesthesia, as well.
Induction of anesthesia is the process of taking a patient who is awake and rendering them unconscious. Maintenance of anesthesia is the process of keeping the patient safely asleep throughout the procedure. Recovery from anesthesia is the period from the time the anesthetic agent wears off, or is discontinued, until the patient is fully conscious.
Usually induction falls into one of three categories. The first is when a short acting anesthetic agent is given to produce rapid loss of consciousness. This is usually followed by a maintenance anesthetic, generally a gas. Another induction method is to use the anesthetic gas as both the method of rendering the pet unconscious and of maintaining that state. The last type is induction with a short acting anesthetic agent that can be given repeatedly until the procedure is over or with an injectable anesthetic agent or combination that serves as both the induction and maintenance agents.
One of the main goals of anesthetic induction is to make it possible for an endotracheal tube to be placed into the patient's airway. When an endotracheal tube is in place anesthetists refer to this as "having control of the airway". A pet with an endotracheal tube in place can be resuscitated more easily and more quickly. This can be a critical issue if an anesthetic problem occurs. Some veterinary anesthetist claim that having an endotracheal tube in place is necessary for any surgical procedure. I tend to disagree with this statement in part. I think that some very short surgical procedures do not justify placing an endotracheal tube. My reasoning is that getting the tube in place is often the most time consuming and difficult part of an anesthetic procedure and some patients have complications due to the process of passing the tube or over-inflation of the cuff of the tube during anesthesia. For the most part we do place an endotracheal tube for surgery in our practice but there are some exceptions when procedures are short.
There are several anesthetic induction agents available for veterinarians to use. A safe combination for most procedures in dogs is ketamine and diazepam (Valium Rx) used in combination. Ketamine in combination with narcotics or xylazine is often used in cats. Anesthetists tend to hate xylazine (Rompun Rx) but our experience with it has been good. Short acting barbituates are favored by some vets but we have more complications using these induction agents than the ketamine combinations. Propofol provides rapid induction and is quickly cleared from the patient's system which allows for a pretty smooth recovery in most patients. It is less likely to cause complications than the short acting barbituates but more likely to cause problems than the ketamine combinations.
Veterinary anesthetists usually don't like induction of anesthesia with gas anesthetic agents (mask or tank induction). Their reasoning is that pets often get very anxious because the gas has a strange odor and taste while it is being administered and the gases work slowly enough that the pet is often aware that it is losing consciousness and fights the process. The flip side of this is that anesthetic gases clear from the pet's system very quickly if they are the sole anesthetic agent and this is safer if complications do arise. Sevoflurane has the fastest induction time and isoflurane is next. Halothane probably shouldn't be used for induction of anesthesia but I would be lying if I said we never did it when were using halothane on a regular basis. We think that mask induction is reasonable for pets who don't find it frightening and that it tends to work well if we administer a sedative and narcotic pain reliever prior to attempting the induction process. However, it is possible that using a quick acting induction agent and intubating the patient is kinder than using a slower acting gas.
Maintenance of anesthesia is frequently managed by using an anesthetic gas such as halothane, isoflurane or sevoflurane. It is possible to maintain anesthesia for long periods of time with the gases, as they continue to work as long as the patient breathes them. It is possible to maintain anesthesia by repeated injections of short acting anesthetics but in general this is a distant second choice to maintenance using gas. The exception to this might be the use of propofol intermittently during surgery because it does clear from the system quickly even after repeated injections.
Local anesthesia is not used as frequently by veterinarians as human physicians, which is one of the reasons that the anesthetic complication rate is higher in veterinary medicine than in human medicine. It is possible to do spinal blocks in pets and some veterinarians are doing these types of procedures more frequently, especially for procedures such as cesarean sections. We have pretty good luck using local nerve blocks with a sedative and pain relief medication for removal of skin tumors.
Probably the single most important thing to remember about anesthetic protocols is that the best one is often the one that your vet is most familiar with. New anesthetic protocols must be learned and the sad fact is that while they are being learned the first few patients are at an increased risk of complications. So even though you may hear that particular anesthetic combination is the safest, best or other superlative, it still might not be a good idea to influence your vet to try it for the first time on your pet. Many veterinarians have great success with anesthetic protocols that veterinary anesthetists don't particularly like.
Monitoring Anesthesia
Most veterinarians monitor their patients in some manner during surgery. The best monitoring technique is a dedicated and knowledgeable anesthetist keeping track of an individual patient during the surgical procedure. If your veterinary practice has a veterinary technician or veterinarian who does this during surgical procedures as an option, it is worth paying extra for. Due to the economics of veterinary surgery it is more likely that the surgeon will also oversee anesthesia, sometimes with the help of an veterinary assistant and sometimes by relying on monitors to provide information during the surgery. Good monitors can provide the surgeon with plenty of information to evaluate the patient's anesthetic state but can also be a distraction.
Pulse oximetry, or the measuring of oxygen saturation in the blood from capillary blood flow, is becoming the standard for surgical monitoring. Capnography, involving the measurement of carbon dioxide levels, is a little more sensitive for impending respiratory difficulty but isn't as widely available and also seems to require a little more attention to the monitor, which is only possible if someone has time to fuss with it. Blood pressure measurement is a very good monitoring technique. Monitoring the electrocardiogram (ECG) can sometimes be helpful but is not as good as the other monitoring procedures, at least in my personal opinion.
It is important that the patient be monitored in some way until consciousness returns and the patient is stable. The recovery period is one of the times when anesthetic complications can occur. If the patient is returned to a cage before swallowing reflexes have returned vomiting can result in severe complications. Hypothermia sometimes occurs in patients during recovery if they are not watched to ensure that they are doing well. Taking care of patients after surgery can slow the surgical schedule down a little but it is well worth the effort.
It is essential that some type of monitoring take place during anesthetic events with the possible exception of very short procedures. Most veterinarians really like to tell you about their monitors so asking how your pet will be monitored during a surgical procedure will usually get you all the information you need.
Anesthetic complications
It is unfortunate, but anesthetic complications do occur in veterinary medicine. General anesthesia is the art of shutting down a patient's conscious brain without shutting down all of his or her brain function and without affecting other organs severely. This is a difficult thing to do exactly right every single time in patients who vary in their ability to handle anesthesia and under pressure due to the surgical procedure itself. While a critical examination of individual anesthetic complications shows that most of them had some degree of preventable human error as a contributing factor, this error rate is almost unavoidable because people simply aren't perfect.
The most common anesthetic complication is probably death during the induction or maintenance phases of anesthesia. This can occur directly from the effects of anesthesia on the brain, especially in pets who are extremely anxious or violently aggressive in the immediate preanesthetic period. It can also occur due to direct effects of the anesthetic on heart and respiratory functions. More commonly, though, it is a matter of several factors interacting in such as a way as to make all of them more serious than any one alone would have been -- a sort of sneaking up of complications until a crisis occurs and the veterinarian has to sort through all the problems quickly enough to save the patient. The only studies with well documented statistics show that veterinary patients have a death rate between 1 in 500 and 1 in 1000 during surgical procedures, on the average. Most veterinarians believe their anesthetic death rate is lower than this but I wouldn't count on it unless it is obvious they are doing everything they can to lower the risks.
It helps a lot to make some preparations to deal with emergencies. Placement of an endotracheal tube to ensure a clear airway is helpful. Placement of an intravenous catheter prior to surgery to allow rapid administration of fluids and medications to combat shock or low blood pressure if necessary, can save a patient's life if a crisis does occur. Keeping patients warm during surgery lessens anesthetic complications so some means of warming surgical patients is good to check for, as well.
Blindness following anesthesia is probably the second most common complication among patients undergoing anesthesia in veterinary medicine. This occurs when blood pressure gets too high or too low, or when oxygenation of the blood is poor during the surgical procedure. Problems with oxygen flow in anesthetic machines that isn't recognized are probably a major cause of this problem. Ketamine sometimes causes blood pressure spikes that cause eye damage even though it is one of the safest anesthetics overall. Poor positioning during dental procedures seems to contribute to this problem at times, as well. Seizures sometimes occur after anesthetic events. This may be due to innate seizure activity in a number of patients but it probably also occurs as real complication of anesthesia in some patients. When veterinary patients have preexisting kidney damage it is particularly critical that blood pressure be maintained during anesthetic events, or additional kidney damage can occur. Endotracheal tubes have cuffs that inflate inside the trachea to ensure a seal. If these cuffs are over inflated they can cause damage to the trachea and in some cases this will cause the pet to die within a few days after the surgical procedure. Oddly, uninflated cuffs have been implicated in some cases as the cause of damage to the trachea, apparently because that ridges in the uninflated cuff are irritating to the trachea. Once in a while it seems like an improperly cleaned anesthetic tube leads to a pet developing tracheobronchitis after surgery.
Remember that you can't shop for the lowest price on a surgical procedure involving anesthesia and expect that your pet will also be given pain relief medications, as well as being well monitored with all of the precautions taken to ensure the best response if an anesthetic crisis occurs. You assume more of the risk for the surgery if you don't ask for and pay for necessary precautions to keep risk to minimum.
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The opinions expressed in this newsletter are those of Michael Richards, DVM., author. Copyright 2003, TierCom, Inc. Thanks for your support!
This page was last edited 06/20/04
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