Veterinarians often have to resort to surgical operations, without which it may be impossible to cure some pathologies. But often it’s not even the operation itself that is particularly difficult! The fact is that anesthesia for cats, without which it can be difficult and even dangerous to do anything with an animal, should be prescribed only by an experienced and competent specialist. Otherwise, the outcome of the intervention will be sad.
The term “anesthesia” itself comes from two ancient Greek designations, the combination of which can be translated as “deprivation of senses.” That is, this procedure is aimed at eliminating sensitivity (local or the entire body) for the duration of some manipulations (surgical, as a rule), accompanied by an increased pain reaction.
Without high-quality anesthesia, the operation will almost certainly end sadly: cases of death from painful shock are far from uncommon. Typically, pain relief is not the only purpose of anesthesia. Very often it is supplemented with local administration of muscle relaxants (that is, drugs that help relax muscles).
A more well-known term is . It involves putting the animal into deep medicated sleep, accompanied by a complete shutdown of all pain. To reduce the dose of the “sleeping” drug and facilitate further recovery from anesthesia for the cat, any general anesthesia is preceded by premedication. This is called the introduction of lungs sedatives and muscle relaxants. Without premedication, induction into anesthesia is much more difficult, and the risk of developing many complications increases significantly.
Any anesthesia can be performed either using one (less often two) drugs, or using a combination of several drugs. In the first case we are talking about mononarcosis, in the second – about polynarcosis (mono- and polyvalent types, respectively).
Simple, one-component anesthesia, despite the ease of implementation and the relative ease of calculating the dose, is an option suitable only for light, short operations. Despite all the successes pharmacists have achieved in recent years, ideal and “multifunctional” drugs for anesthesia still do not exist.
In particular, there are no such means (especially in veterinary medicine) that would allow long operations. If complex surgical intervention is necessary, in any case it is necessary to use a combination of several drugs that enhance or smooth out the effect of each other.
She is also “ gas anesthesia». It is believed that inhalational anesthesia is the most preferred method. There are several reasons for this:
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However, in the latter case, not everything is so smooth. It is not always possible to supply a gaseous mixture through a mask, and therefore one has to resort to the same tracheal intubation. Because of this, the possibility of operating on many organs of the respiratory system is significantly reduced.
Important! In addition, inhalation anesthesia (due to its pronounced vasodilating effect) is characterized by a serious drop in blood pressure. To avoid death (or development of neurological disorders) of the cat from arterial collapse, blood pressure must be monitored throughout the operation.
The most common type of anesthesia is when drugs are administered intravenously into the animal's body.
This technique also has a number of significant advantages:
Of course, parenteral anesthesia also has its disadvantages:
Important! In veterinary practice, “pure” inhalation or intravenous types of anesthesia are used only in cases of relatively simple and quick operations.
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If complex abdominal surgery is required (for sterilization with the need to remove the uterus and ovaries, for example), combined types of anesthesia are used. Thus, a specialist can carry out primary anesthesia by introducing necessary medications intravenously, after which the cat is kept in the desired state by administering maintenance doses of drugs in the form of an aerosol (through tracheal intubation).
It is carried out by gradually reducing and further stopping the supply of anesthetic substance. In some cases, drugs that support cardiac and respiratory activity, as well as drugs that block the action of anesthetics, are additionally administered.
The most common and simplest type of pain relief. It is used only in cases where it is necessary to perform a quick and simple operation. However, there are exceptions: during castration, local anesthesia is also practiced. But only in young and physically strong cats. Old animals in this case may die from painful shock.
In this case, a patch soaked in solutions of sedatives is glued to the previously shaved skin. The method is good for its simplicity and, contrary to the opinion of some breeders, efficiency: modern drugs perfectly penetrate the skin and can provide high-quality pain relief for several hours.
True, effectiveness is not enough for surgical intervention. As a rule, applications are used to relieve post-operative pain, pain of rheumatic origin, and after sprains.
Unlike the previous version, this local anesthesia is actively used when performing minor (and not so minor) operations. The essence is to inject the future surgical field with solutions of anesthetic drugs so that they permeate both the skin itself and all underlying tissues.
The technique is quite simple: first, the needle is inserted to a depth of several millimeters, and then moved lower. All this time, the specialist presses on the syringe plunger, distributing the product solution into the tissues.
This includes various types of blockades. Without going into anatomical and physiological details, the essence of regional anesthesia in all its manifestations is the impregnation of local nerve trunks, endings and nodes with anesthetic solutions. They block transmission nerve impulses, as a result of which painful sensations either disappear completely or are significantly suppressed.
This technique is divided into three subtypes:
Inhalation anesthesia- a type of anesthesia in which its effects (sleep, muscle relaxation, analgesia) are achieved by administering an anesthetic through the patient’s lungs. Anesthetic molecules penetrating into respiratory system patient, pass the pulmonary capillary barrier, are transported circulatory system to the tissues of the body, reaching the final goal - brain tissue. When the required concentration of the drug is reached in nerve tissue There is a reversible depression of consciousness in the patient, muscle relaxation and sleep required for surgical intervention. Compared to TVA (total intravenous anesthesia, in which an anesthetic is injected into a patient's vein), inhalational anesthesia has comparatively better controllability and a unique route of absorption and elimination (excretion) of the anesthetic. This type of anesthesia has no direct effect on other organ systems, for example, on the excretory system of the kidneys.
Equipment required to perform inhalation anesthesia in the clinic:
There are several ways to deliver the anesthetic mixture to the patient. The doctor may use an induction chamber, a mask, or administer an anesthetic through an endotracheal tube. What are the main differences between the methods?
The induction chamber (induction of anesthesia) is a transparent container into which the patient is placed. The anesthetic is delivered directly into the confined space of the container. Thus, with minimal physical contact, the patient enters a state of anesthesia. The disadvantages of this method of gas supply include the inability to clearly control the depth of anesthesia, perform hardware monitoring (capnography, pulse oximetry, etc.), high consumption of anesthetic and, accordingly, harm to personnel. This type of induction is used in wild and laboratory animals, as well as in overly aggressive patients.
The anesthetic mixture can also be administered using a mask. To do this, the mask must be of the recommended size to prevent leakage of the anesthetic. The main advantages and disadvantages are similar to those of the induction chamber, the only differences being the possible preliminary sedation of the patient (not every animal will allow a mask to be put on) and the need to secure the animal at the time of induction of anesthesia.
Delivery of the drug through the endotracheal tube is the main method used in anesthesiological practice. The anesthetic enters the lungs through a tube made of non-toxic plastic, polyvinyl chloride (PVC). Previous intubation (insertion of a tube) is usually performed under the influence of a short-acting intravenous anesthetic. This type of drug supply allows you to maintain airway patency and monitor the composition of gases in the mixture.
The first officially recognized anesthesia was ether anesthesia (1846). The ether had a number of side effects, unwanted effects. In modern anesthesiology, about six inhalational anesthetics are used: nitrous oxide, fluorotane, enflurane, isoflurane, sevoflurane and desflurane. Unlike its predecessors modern anesthetics much less toxic. In addition, modern equipment allows the anesthesiologist to control the flow of anesthetic gas at the level necessary for surgical intervention.
Gas inhalation is a fairly common type of anesthesia in veterinary practice. It is used both in mono mode for short, painless procedures, and in combined/combined anesthesia for long-term interventions. To achieve the optimal degree of pain relief, it should be noted that inhalational anesthetics- drugs with low level analgesic effect, regional blocks are used and intravenous administration various types analgesics. IA is unacceptable in situations where there is severe respiratory failure, hypotension, inability to maintain airway patency (intubation).
Gas anesthesia- a necessary medical instrument that allows veterinarians to work with immobile animals. With inhalation (gas) anesthesia, the animal being operated on is not pained and does not experience stressful situations due to diagnostic or surgical procedures.
Modern inhalation anesthesia is a method of anesthesia in which volatile gaseous anesthetics (vapors) enter the animal’s body through the respiratory system and cause anesthesia, and, depending on the concentration of the substance, sedation, analgesia and mirelaxation.
When a cat or dog (another animal) undergoes surgery, the topic of anesthesia becomes so relevant for the pet owner that in some cases they are ready to refuse surgical intervention, just so as not to cause unnecessary harm to their furry (feathered) friend.
"The ideal anesthetic"
There is a term in science - “ideal anesthetic”, but it still remains a purely nominal concept, since work on its creation continues. An ideal anesthetic must meet certain requirements:
Quick and comfortable recovery from anesthesia;
Create a strong hypnotic effect and well-expressed muscle relaxation and analgesia;
Be non-toxic;
With well controlled depth of anesthesia;
With minimal side effects;
Be environmentally friendly;
And have a low cost;
An ideal anesthetic does not yet exist in nature, but gas (inhalation) anesthetics have already come as close as possible to the desired result in many respects. No injectable anesthesia drug can boast amazing properties that inhalation anesthesia has.
The choice of a modern veterinarian-anesthesiologist is often not great, and the point is not a lack of knowledge, but the “unsinkable bureaucratic boat” into which many doctors of various profiles find themselves. Currently there are many good drugs used in veterinary medicine for anesthesia. But, many drugs can be used only after obtaining a license for the right to use, but only a few can have them, since it is impossible to issue the necessary documents in Russia “without losses.”
Today, an anesthesiologist has such an anesthetic as isoflurane in his arsenal. It was synthesized in 1965, but wide application reached only in the 80s, and began to be used in veterinary medicine only in the late nineties. All veterinary specialists noted its amazing effect when used. It is low-toxic, does not have many contraindications and side effects.
Mechanism of action of gas anesthesia
It is generally accepted that general anesthesia depends on the concentration of the drug in the brain tissue. Inhalational anesthetic affects the cortex cerebral hemispheres, sphenoid nucleus of the medulla oblongata, hippocampus and other structures. There is no limited area of the brain that can be targeted by anesthesia to produce the desired effects. The centers that control consciousness are the first to be affected by anesthesia, and the vital areas (respiratory, vasomotor) remain more resistant to the effects of the anesthetic. Due to these abilities, animals in a state of general anesthesia can maintain spontaneous breathing and close to normal blood pressure and heart rate.
Brain neutrons become a “target” for molecules of inhaled anesthetic drugs. The path to the brain schematically looks like this: anesthetic drug (evaporator) – respiratory circuit – lungs (alveoli) – blood – brain.
General inhalation anesthesia occurs when the anesthetic molecules reach the brain neurons, and for this they must enter the respiratory circuit, through the lungs into the blood, and only then they find themselves in the body tissues.
Elimination is the reverse process of absorption, when the concentration of anesthetic in the brain begins to decrease, the animal gradually awakens. Using the evaporator, the veterinary anesthesiologist reduces the dose of anesthetic, its partial pressure on the respiratory circuit and lungs decreases, and the partial pressure in the blood, on the contrary, increases. The venous gradient forces gas to pass from the blood to the alveoli of the lungs, from where it is expelled. Thus, the anesthetic is removed from the animal’s body in the same way as it entered
Isoflurane is most often used for inhalation anesthesia, since due to its low solubility it is metabolized by no more than eight percent and is excreted unchanged through the lungs. It is a powerful anesthetic and has a pronounced muscle relaxant and hypnotic effect.
Whatever means of inhalation anesthesia is used to reduce the risk of surgical interventions ah, it is necessary to correctly apply a set of measures: gas anesthesia + artificial ventilation lungs + ECG, something that will help carry out the operation with minimal difficulties.
Veterinary center "DobroVet"
“I was told that the operation could not be performed because my dog (cat) would not tolerate anesthesia” - veterinarians often hear this phrase from pet owners. We talked about where this myth came from, why it continues to live and what modern veterinary anesthesiology actually is, with the chief physician of the Biocontrol veterinary clinic, head of the department of anesthesiology, resuscitation and intensive care, president of the veterinary anesthesiological society VITAR, candidate of biological sciences Evgeniy Aleksandrovich Kornyushenkov.
— Please tell us, first, what types of anesthesia for animals exist?
— There are the same types of anesthesia for animals as for people. This is an intravenous injection of the drug. In some cases, for aggressive or restless animals, an intramuscular option is used to calm them down and then insert a catheter. Next, IV medications are administered, then intubation occurs (placement of a tube in respiratory tract) and is then carried out gas anesthesia.
Regional anesthesia, that is, local, is also possible and encouraged.
— Does it happen that several types of anesthesia are used at once?
— Yes, such anesthesia is called combined.
— What procedures are performed on animals? general anesthesia and why?
— For animals, unlike people, general anesthesia is a very common procedure. The reason is that a veterinarian does not always have the opportunity to conduct a high-quality examination of patients. After all, our patients cannot lie for a long time with open mouth if you need to conduct an examination oral cavity, or lie motionless under an X-ray machine or in. Sometimes animals do not allow the surgeon to fully examine the joints, and then the animal has to be sedated so that the animal calms down and relaxes. Sedation is light anesthesia, and anesthesia is deeper.
Also, of course, all surgical interventions are performed under anesthesia. Well, inspection of aggressive animals.
— What methods of anesthesia are used at Biocontrol?
— Our clinic uses all modern techniques, including the most advanced ones, such as using a neurostimulator to carry out blockades. That is, we connect a special device to find the nerve, and apply anesthesia near this nerve. This allows you to reduce the amount of general anesthesia and perform the operation only due to this anesthesia technique. That is, there will be less general anesthesia, there will be fewer consequences, and the animal’s recovery from anesthesia will be better and of higher quality.
— What is special about gas anesthesia?
— The fact is that gas enters the lungs and also exits back through the lungs. It is not metabolized in the liver and kidneys, so for patients with concomitant diseases of these organs, such anesthesia is safe.
— Do animals have any contraindications to general anesthesia? Weight, for example, or age?
— Of course, animals have contraindications to general anesthesia. As for age, it's controversial issue. Age may or may not be a limitation for anesthesia if anesthesia is necessary for health reasons. The question is not the age, but the condition of the animal. For this purpose, the anesthesiologist examines the animal before surgery.
— What does the anesthesiologist pay attention to when examining an animal before surgery?
- In animals with complex clinical situation have to resort to additional research, such as ultrasound of the heart, taking blood tests, including a coagulogram and gas-electrolyte composition. These diagnostic tests allow the anesthesiologist to determine the degree of risk. There is a scale of anesthetic risk with five degrees. Due to the specifics of our clinic, we most often deal with animals from risk levels 2 to 4.
- What kind of degrees are these?
- For example,
Therefore, based on this scale, we have no desire to give an animal with grade 5 anesthetic risk anesthesia. It is given only if there is at least a minimal chance that the operation will provide an opportunity for survival. It is necessary to discuss with the owners that the animal can die at the stage of induction of anesthesia, during the operation, and immediately after the operation. That is, the risk is maximum, and is associated not only with anesthesia, but with the entire procedure in general. But operations cannot be performed without anesthesia. Anesthesia exists precisely so that the animal undergoes surgery.
— Why then is age a contraindication to general anesthesia in other clinics?
- This is wrong. These are clinics that, apparently, do not have normal anesthesiology equipment and staff. Not every clinic has the opportunity to have specialized anesthesiologists on its team. Yes, this direction is developing, but not in every clinic. Since 1992, Biocontrol has operated an entire anesthesiology service, that is, doctors who deal only with anesthesiology and understand this issue much more than doctors who are simultaneously surgeons, anesthesiologists, therapists, and dermatologists all rolled into one. Doctor who provides wide range services, may not be a professional in all areas. Our people are engaged specifically in this specialty, and they, as opinion leaders, are responsible for the adequacy of decision-making, the adequacy of such a concept as “correct anesthesia.”
— Describe the process of putting an animal into a state of anesthesia.
— First, the animal is examined by an anesthesiologist. If there are no contraindications, the patient is allowed to undergo a particular procedure. If the procedure is not complicated, then, as a rule, premedication is not done. An intravenous catheter is placed in the presence of the animal, then an intravenous drug is administered, and it falls asleep. Afterwards, an examination or procedure is carried out and our patient wakes up quite quickly.
If we are talking about surgery, then 10-15 minutes before the procedure itself, premedication is performed intramuscularly or subcutaneously, that is, preparing the animal for anesthesia. Premedication includes different drugs, including sedatives, and drugs that prevent cardiac arrest. Premedication is not mandatory; only a specialist decides whether it is necessary. After premedication, an intravenous catheter is placed and anesthesia is administered. In 99% of cases, this drug is Propofol, which has long proven its effectiveness and safety and is one of the most common among induction drugs (drugs for immersion in anesthesia). Next comes tracheal intubation - this is an almost mandatory rule. A tube is inserted so that the animal can breathe calmly during the operation and nothing interferes with it. Oxygen flows through it, and after intubation the animal can be transferred to gas anesthesia so as not to inject it intravenous drugs. Also required various options pain relief. If this systemic drug, then it is also administered intravenously, and if the regional anesthesia technique is also used, then either epidural anesthesia or, as we have already said, a neurostimulator is taken.
— What if you don’t use painkillers? Will the animal feel anything? It's sleeping, isn't it?
— During operations, various psychophysiological parameters of the patient, heart rate and respiratory movements are necessarily measured. That is, if the animal is in pain, all these parameters will increase. And although the animal is not conscious, these indicators will increase, including, possibly, a motor reaction. This is unacceptable.
— Still, do animals feel anything during surgery?
— There is a concept of “anesthesia.” This is a reversible loss of consciousness. This has nothing to do with pain relief. And there is the concept of “analgesics”. These are the drugs that eliminate pain sensitivity. Accordingly, the analgesic does not immerse the patient in deep sleep. He may be sleepy, that is, sleepy, but he will not be completely asleep, but he will not feel pain. An anesthetic is needed to ensure that the animal sleeps and does not move. If you administer only analgesics, the animal will not allow you to work normally. Therefore, two components are always introduced: both anesthesia and analgesia. And, of course, muscle relaxation is required - muscle relaxation. These are the three mandatory components of a complete anesthesia care.
— How is the animal’s condition monitored during surgery?
— The patient is connected to special sensors to assess the parameters of his condition. To control work cardiovascular system An ECG is performed and blood pressure is monitored using various methods. We also evaluate oxygenation, which is the level of oxygen supplied to the animal. We evaluate ventilation - how the animal releases CO2, whether it accumulates in the body. We evaluate diuresis; for this, patients are given urinary catheters- this is very important during long-term operations. We use an easy-to-use instrument called an esophageal stethoscope, which is inserted directly into the esophagus.
Biocontrol has high-tech equipment - anesthesia-respiratory machines. In them, all indicators are included in a single block. The patient is connected to the equipment, and the anesthesiologist's job is to monitor how the device works. These devices are so “smart” that they themselves adapt to the patients. That is, even if the animal does not breathe, the device itself will do it for him. Today, the greatest responsibility lies with the anesthesiologist during the introduction of the patient into a state of anesthesia and connection to the anesthesia-respiratory machine, and then during his awakening. But even though the anesthesiologist has special equipment, he must look at the animal clinically.
— How is recovery from anesthesia carried out?
— Approximately 10 minutes before the end of the operation, when the surgeons are already suturing the surgical wound, the anesthesiologist reduces the amount of drugs supplied to the animal. The gas and the flow of analgesics decrease, and by the last suture the animal should already be breathing on its own. If the operation was not very complicated, planned, then the patient is transferred to spontaneous breathing, and he is placed in our anesthesiology and intensive care unit, where he wakes up smoothly and carefully. He is immediately prescribed painkillers various groups. Some people require stronger painkillers that last for several days. In such cases, the animal has to spend some time here in the clinic.
— Why operations and other procedures under general anesthesia should be carried out exclusively in specialized clinics, and not at home?
- At modern conditions, which can be provided exclusively in the clinic, death at operating table becomes very rare, with the exception of operations on the chest cavity or neurosurgical operations, in which the risk of surgical error is high. However, if any difficulties arise, the clinic has the opportunity to attract an additional team of doctors who can help. In specialized clinics, like ours, there are defibrillators that can start the heart. There is one that can be used immediately in case of sudden bleeding and save the animal. All this is impossible at home.
For the same reasons, the animal should be monitored in the clinic and after surgery. One of the common complications after surgery, especially for small animals, is cooling. Anesthetics affect certain centers of the brain, including the thermoregulation center. Inhibition of this center causes the body to cool down. A small dog when it's open abdominal cavity, in half an hour of surgery it can lose up to 2.5 -3 degrees. Modern heating system based on infrared radiation, which we have installed, helps to avoid such problems.
Another important fact is pain relief. You cannot use the same painkillers at home as in the clinic. This is prohibited by law. That is, if the owner wants his animal to be anesthetized, then he must understand that at home he will not be able to provide such an opportunity. Even such seemingly simple operations as sterilization and castration are very painful.
- What types are there? side effects from anesthesia?
“We must understand that there are no bad drugs, there are no simple manipulations. There are bad anesthesiologists. It should not be surprising that one of the drugs can cause side effects from the heart, from the respiratory side, from the temperature side, induce vomiting - for the reason that all anesthesia agents affect the centers of the brain. One of the centers is the brain stem; when exposed to it, drugs turn off consciousness, putting the patient to sleep. And the other center is located in the medulla oblongata - this is the cardiovascular, respiratory, thermoregulation, and vomiting center. Absolutely all drugs affect these centers, thereby reducing the heart rate, respiratory rate, causing vomiting, and lowering the temperature. They just work to a greater or lesser extent.
All these effects are regulated by the anesthesiologist himself. If the patient is stable and connected to the monitoring system (that is, the operation is performed in a clinic and not at home), then all these drugs, even if there are side effects, are a benefit. But performing an operation without anesthesia means certain death. Anesthesia was invented to help patients endure operations.
But we should not forget that there are various phenomena that cannot be predicted. For example, such a thing as malignant hyperthermia is very rare. This is a genetic defect of the gene, and some anesthetics cause a reaction that will most likely lead to death. Such a factor as an allergy to anesthesia has long ceased to exist in modern anesthesiology. This is a kind of myth that was invented by people who are not exactly anesthesiologists and are trying to justify their failures in this way.
— Does it have an impact in the future? general anesthesia, as well as the number of procedures performed under anesthesia, on the patient’s health and life expectancy?
— In our practice, there are many examples when anesthesia is prescribed to a patient almost every day, for example, when a tumor is irradiated for five days in a row in small fractions, which is carried out under anesthesia. There are patients who received 15-18 anesthesia per year during treatment. This had no effect on life expectancy, given their illnesses.
In our clinic, each manipulation point is equipped with oxygen, and there are racks with inhalation anesthesia, which is safe method, as we already said. That is, we can provide anesthesia for both X-ray and radiation therapy, both on CT and during oral cavity sanitation. We have 9 anesthesia-respiratory machines - a fleet that is inaccessible to many clinics.
Moreover, we have patients who undergo operations such as bone transplantation. During such an operation, the patient is under anesthesia for 10-12 hours. Afterwards he passes intensive care, 2-3 days in intensive care for various means control, but even if there is concomitant diseases animals successfully undergo this operation. But to ensure that your pet can return home in a timely manner, a whole team of specialists works. And the anesthesiologist is one of the most important links in it. It is he who initially makes the decision on the possibility and advisability of the operation and is responsible for the patient’s condition. The owner themselves will never be able to adequately decide whether the pet will undergo the procedure under general anesthesia or not. This is the deepest misconception that is imposed on owners by non-professionals.
Owners of patients such as rabbits, guinea pigs, hamsters always get scared when they hear from a veterinarian about anesthesia, anesthesia, and sedation. However, anesthesia is a truly necessary medical tool. It allows veterinarians to work with immobile animals without causing pain or stress during diagnostic procedures and surgical interventions. Let's look at all the pros and cons of anesthesia for “unusual” patients.
Rabbits, rodents, birds and wild animals are subject to severe stress during most diagnostic procedures, which require prolonged restraint in an unnatural position or result in even minor pain. Such stress can cause serious disorders in the body, and sometimes can lead to the death of the animal from shock or injuries received during attempts to fix it. This is due to the physiological characteristics of small and herbivorous animals, the main of which is the production huge amount adrenaline compared to cats and dogs in response to any stress and pain.
Here the owners will immediately say: “But anesthesia will kill a hamster or a rat! “This is a somewhat erroneous opinion.
With adequate anesthesia, the mortality rate of “non-standard” patients during simple surgical interventions and diagnostic procedures is below one percent. Naturally, no one cancels individual intolerance to drugs or serious systemic diseases, the presence of which increases the anesthetic risk during anesthesia in any patient. In general, the degree of potential risks to the animal's life is always assessed individually and discussed with the owner before any procedures under sedation are performed.
At the Zoovet EC, we use inhalation anesthesia (also known as “gas”) as anesthesia for small and exotic patients. This type of anesthesia is a generally accepted tool in working with small and exotic animals due to its greatest safety for them. We use isoflurane as the main drug when performing gas anesthesia. If stronger pain relief is needed during major surgical procedures, it is possible to use a variety of available painkillers, but inhalational anesthetics form the basis.
Why are inhalational anesthetics so safe?
Isoflurane has virtually no absolute contraindications due to the fact that it enters the body and is excreted back through the lungs. In this case, the substance is practically not metabolized to form toxic products decays, which can usually give postoperative complications when using intravenous or injection anesthetics.
Using gas anesthetics, an anesthesiologist can easily and, most importantly, quickly change the depth of anesthesia, since it is always possible to control the concentration of narcotic drugs in the air supplied to the patient by special equipment, which is impossible to do when using injectable drugs anesthesia
During anesthesia, any organism is always subjected to artificial suppression of its functions. This is especially important for young patients, since they are more prone to hypothermia due to the ratio of the surface area of their body to its mass. After stopping the supply of gas anesthetic to the animal, the process of awakening (reversion) takes a short time, on average about 15 minutes, which does not allow the patient to become hypothermic due to a long stay in a state of anesthesia.
By comparison, reversal in mice using a regimen using injectable drugs such as xylazine and zoletil takes one to two hours, depending on the initial dose of drugs injected. At the same time, it becomes quite difficult to keep the animal’s body temperature at an adequate level for such a long time; the patient can easily overheat on a heating pad or become hypothermic in a matter of minutes, which will lead to death.
Gas anesthesia for animals has some disadvantages. When anesthetizing a small hamster, it takes no less anesthesia than a dog. This is due to the metabolic rate and the ratio of the size of the functional surface area of the lungs to the size of the animal itself, as well as the technical features of the process. Thus, the cost of anesthetic drugs used for rodent surgery is often equal to that of larger animals.
Overall, gas anesthesia did possible to carry out operations and diagnostic procedures in patients such as birds, rodents, and many reptiles. This helps not only to increase the percentage of cured patients, but also to the development of exotic veterinary medicine in our country.
