Many owners are worried about how their pet will endure surgery, which requires anesthesia.

Risk of anesthesia in rabbits – key factors

There are many factors that can influence the risk of anesthesia in rabbits. Among them, especially notable

• stress,
• a number of previous diseases,
• hypoxia.

Thanks to a clinical examination before the procedure, the current condition of the animal can be established. Weighing will help calculate the dosage of drugs administered to the animals. Thanks to modern equipment, high-quality and accurate calculation doses and monitoring are achieved as safely as possible.

Preliminary clinical examination

Thanks to a clinical examination, it is possible to establish the general condition of the animal before anesthesia. Individuals in shock, hypotension or dehydrated require close attention - a specialist injects such rabbits with nutritious fluid intravenously or intraosseously.

Rabbits do not have a gag reflex, and as a result, anesthesia can be performed practically. Within 1-2 hours there will be no food particles left in their mouth, and there will be enough space in their stomach.

After anesthesia, the animal requires a constant flow of oxygen into the lungs. Thanks to oxygenation, the risks of hypoxia can be significantly reduced. Air can be supplied through an oxygen mask, through nasal or endotracheal tubes, and through a channel inserted into the pharynx.

Thanks to endotracheal intubation, the risk of prolonged breath holding in animals is significantly reduced, and oxygen can be introduced into the lungs. This will avoid mortality. Also, this procedure, in case of complications, will allow artificial pulmonary ventilation.

Intubation of animals

To intubate a rabbit, it is important to consider anatomical features their trachea, oral cavity and nasopharynx. take into account the small volume of the lungs and perform the procedure in such a way as to avoid hypoxia in the animal. Compared to the abdominal region, the lungs of these animals are very small - their volume is no more than 5-6 ml/kg. Thanks to the movement of the diaphragm, they breathe - the lungs do not work due to the muscles of the intercostal part of the body. The specialist makes sure that the animal’s abdominal organs do not put pressure on the diaphragm.

Pulse oximeter

A pulse oximeter is used as an element of anesthesiological equipment. The ideal place to attach it is the rabbit's tongue. But these actions will be impossible if the muzzle is under an oxygen mask. A clear signal will come from the base of the tail or inguinal folds, but this will require plucking the fur. Also as additional equipment a rectal probe is used.

Rabbits differ from other laboratory animals in their calmness and relatively weak resistance to fixation. They are tied to special machines or vivisection tables in the same way as cats and dogs. It should be borne in mind that when the head is thrown back strongly, rabbits can easily die from suffocation. An assistant can fix the rabbit with both hands, holding it with the left hand on the skin of the back in the back of the head, and with the right hand on the sacrum or hind limbs.
A convenient way to secure rabbits is using an individual box with a round slot in the front wall or a special immobilization machine. In this case, the animal’s head is brought out through the hole in the front wall, and the body is placed inside the pen (cage, box; Fig. 56). Using an insert board, you can reduce the internal dimensions of the box depending on the size of the animal.

Anesthesia and sedatives

Anesthesia is achieved when sensation is lost in any part of the body or in the entire body. General anesthesia renders the patient completely unconscious. Sedatives are similar to general anesthesia, but the patient remains half conscious. Anesthesia and sedatives are used in veterinary medicine in different situations(X-rays, intravenous procedures, biopsies, etc.). They are also used to calm animals that are aggressive or in severe pain, as well as to check the nasopharynx area and for operations.
Types of anesthesia Local anesthesia - used to turn off pain sensitivity in a specific area of ​​the body. The rabbit remains conscious. Local anesthesia can be used for skin surgeries or biopsies, for the installation of intravenous and other catheters, or for ophthalmic procedures (rinsing the tear duct, etc.).
Regional anesthesia - wider and deeper areas are deprived of sensation. The anesthetic is injected, for example, into the cerebrospinal fluid, causing the entire part of the rabbit's body below the injection site to become numb. An anesthetic can also be injected into the area where a specific nerve passes (conduction anesthesia), then the entire area to which this nerve is connected will be “frozen”. The rabbit remains fully conscious. This type of anesthesia has been successfully used in rabbit veterinary medicine.
General anesthesia - the anesthetic circulates through the circulatory system, including penetrating the brain, causing the rabbit to completely lose consciousness. There are two methods of administering general anesthesia: injection and inhalation. Injectable anesthetics are administered intramuscularly (IM), intraperitoneally, or subcutaneously (SC). Injectable anesthetics are often used for short procedures (especially in the oral cavity) or are used as a combination anesthesia followed by the use of gaseous drugs. In this case, they are used to calm the rabbit so that the rabbit can be intubated as carefully as possible (a tube is inserted into the rabbit's airway, through which gaseous anesthesia is supplied).
The biggest disadvantage of injection anesthesia is the difficulty of calculating the dosage, which is individual for each rabbit. It is also impossible to control the dose once it has already been administered (with the exception of reversible drugs). Injection anesthetics (without any additional agents) cannot be used for long-term operations. The duration of anesthesia depends on the drug used. In addition, some types of injection anesthesia lead to cardiac disorders and kidney damage. At the moment, the most commonly used drugs are: ketamine, relanium (Valium), butorphanol, propofol, medetomidine, opiates.
Gaseous anesthetics - the best choice for most operations. As mentioned above, before using the anesthetic gas, it is necessary to premedicate the animal so that it does not resist. Gaseous anesthesia is administered by mask or intubation. The patient receiving the anesthetic gas is connected to a machine that delivers the anesthetic into a stream of oxygen. The advantage of gaseous anesthetic is that the concentration of anesthetic can be quickly adjusted since the patient is connected to oxygen at all times. Recovery from such anesthesia is usually quick and gentle. In addition: isoflurane is the most common gaseous anesthetic and is safe for rabbits with various types diseases, and it is also safe for medical personnel. Methoxyflurane and halothane, widely used on rabbits in the past, are quite dangerous for doctors working under these types of anesthesia. In addition, methoxyflurane is dangerous for obese rabbits.
Risks of general anesthesia If careful preparation and monitoring of the patient is carried out, the risk of general anesthesia is reduced to a minimum. However, it would not be true if we said that there is no risk at all. Medicine is not an exact science because we deal with complex and individual organisms. Complications during general anesthesia occur due to respiratory arrest, palpitations, and brain hypoxia leading to death. IN in experienced hands, death from anesthesia is rare. The most common causes of death from anesthesia are cardiac or respiratory arrest, often occurring against the background of hypothermia (low body temperature), hypovolemia (low blood pressure), embolism (blockage of blood vessels). Respiratory or cardiac arrest can result from a variety of factors, including disease in the chest cavity (including the heart or lungs), other systemic diseases (especially those affecting the liver and/or kidneys, through which the anesthetic is eliminated from the body), blockage of the air supply tube (with stomach contents, blood) or an overdose of anesthetic.
A slight decrease in temperature is natural during general anesthesia, since metabolic processes slow down under anesthesia. Anyone who has ever been under general anesthesia probably remembers how when you woke up you were shaking from the cold. A rabbit's temperature can drop to a critical level very quickly, especially if it is opened abdomen or the operation takes a long time. Hypovolemia occurs when a patient loses a critical amount of blood or other fluids from the body during surgery, or if hydration levels are not corrected before surgery.
Embolism is fortunately rare, but can occur at any time, especially if the operation involves large blood vessels, bone tissue, or if the rabbit had a serious bacterial or fungal infection before the operation.

Factors that reduce the risk of general anesthesia

Fortunately, there are many things that can be done to reduce the risk of anesthesia. Factors that increase the risk: lack of preoperative evaluation of the animal, disease (especially respiratory, cardiac, renal or hepatic, dehydration or obesity), inappropriate anesthetic or incorrect dose, lack of monitoring during surgery, or lack of adequate postoperative monitoring of the animal and appropriate care.
Here are some things veterinary staff can do to reduce the risk of anesthesia and surgery:
-conduct preoperative examination of the animal, including diagnostics
-stabilize/cure concomitant diseases
-use an anesthetic suitable for rabbits and calculate the dosage correctly (you need to know the exact weight of the animal)
- constantly monitor the animal’s condition during anesthesia/operation
-monitor the animal closely after surgery until it wakes up and begins to move

Treatment of existing diseases

It is important to stabilize or treat any conditions present at the time of the rabbit's physical examination, such as: dehydration, infections, liver or kidney disease, heart or lung disease. The most common situation that complicates the final decision in favor of surgery is the obesity of the rabbit. Obese rabbits are always at greater risk when going for surgery, the reason is possible liver disease (fatty liver, lipidosis) and respiratory problems - pressure excess fat on the chest.
Unless there is a life-threatening situation that requires immediate surgery, an obese rabbit should lose weight before undergoing surgery that requires general anesthesia.
*Important: Please note that some diseases occurring in the rabbit at the time of surgery may go unnoticed. As stated above, we are dealing with complex organisms, and not all tests will be able to detect the disease in a rabbit. However, situations where the disease remains undetected after a full examination are rare.

Administration of anesthetic

Due to the very nature of the rabbit, the specific structure of its gastrointestinal tract, and the fact that the rabbit cannot vomit, it is not necessary to deprive the rabbit of food before surgery. Some veterinarians prefer to remove food a couple of hours before surgery to ensure that the rabbit's mouth is clear of food. Technique for performing an operation under general anesthesia When your rabbit loses consciousness (under general anesthesia or partial loss of activity under the influence of premedication), he is placed on a warm pad to avoid hypothermia. In some cases, an additional heat source may be required). If the anesthesia tube has not yet been inserted, it will be installed now. If an intravenous catheter has not been placed before, it will be placed now that the rabbit is unconscious or immobilized. With the exception of short procedures for healthy animals (dental manipulation, etc.), it is recommended to have an intravenous catheter installed so that in an emergency you can quickly and easily give the rabbit the necessary medications or physical therapy. solutions.
Most rabbits undergoing lengthy surgeries must receive intravenous fluids to avoid dehydration and compensate for blood loss. It is advisable that the solutions be heated so that they help maintain the animal's normal body temperature. Monitoring the animal during surgery There are several indicators that need to be monitored during anesthesia and surgery. Breathing - Breathing can be monitored visually and is usually monitored by a surgical assistant. You can also use a stethoscope. Heart Rate/Pulse - Heart rate can be monitored using a stethoscope, ECG machine, or pulse oximeter. Body temperature - body temperature is measured using a thermometer (rectally). Reflexes - testing your rabbit's reaction to certain physical actions will help determine the depth of anesthesia.
There are several methods of such testing, but the most common method is touching the animal's eye. If the doctor touches the rabbit's foot and the animal tries to move its paw to the side, if the doctor touches the rabbit's eyelid and the rabbit tries to blink, this indicates that the animal may still feel pain (then anesthetic will be added).

Post-operative care

When the procedures are completed, the rabbit is on the path to recovery. The aerosol anesthesia will be stopped and oxygen will be given for a few more minutes before disconnecting the rabbit from the machine. The tube will be removed when the rabbit begins to show signs of awakening. Reflexes will be tested again. Your rabbit will most likely be moved from the operating room to another area that should be fairly quiet but with staff present to monitor the animal. The amount of heat your rabbit will need after surgery depends on its body temperature at the end of the procedure. Most rabbits will only need a short period of artificial heating. Breathing and pulse will still be checked until your rabbit finally wakes up.

Analgesia

Despite the fact that the topic of this article is anesthesia and surgery, we cannot ignore this important aspect of postoperative care. As mentioned above, pain relief can relieve your rabbit of severe, life-threatening stress. Many years ago, when we did not yet understand how important analgesia was, we would lose rabbits within 36 hours of surgery. The operations were successful, but the pain was killing the rabbits. A rabbit in pain will recover more slowly, so pain relief is absolutely necessary after most surgeries. The most common analgesics successfully used in rabbits are: butorphanol, buprenorfone and non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin, carprofen (rimadin), diclofenac, flunixil, ibuprofen, indomethacin, ketoprofen, meloxicam, acetaminophen, piroxicam. An alternative source of analgesia for rabbits in chronic pain is acupuncture. Behavior of Rabbits After Anesthesia and Surgery Quiet Behavior - Your rabbit may be constantly sleepy and remains quiet. Lack of activity may be due to remaining anesthetic in the blood, pain, or other medications. Some painkillers have a sedative effect and may cause the animal to become lethargic. If your rabbit remains in this condition for an extended period of time, sits hunched over, and is unable to move normally, you need to contact your veterinarian.
Poor appetite - Your rabbit may completely refuse food and water for the first 24 hours after returning home.
Analgesics may improve the situation, but will not have a fundamental effect. You can force-feed your pet (from a syringe) a mixture of vegetable puree and fruit juice once or twice during these 24 hours. If after this period your rabbit still refuses to eat, contact your veterinarian immediately. Abnormal stools or no stools - Anesthetics and analgesics can weaken your rabbit's intestinal motility. Additionally, your rabbit may not have eaten much before surgery. In the first three days, stool may be absent or appear irregularly, and the pellets may be smaller and softer than usual. All these problems should go away within three days.
Loose stools (diarrhea) are a cause for concern. If you observe this disorder, contact your veterinarian. Questions to ask your veterinarian Level of training - Ask your veterinarian how often he has had to work with rabbits. He may not have that much experience with these animals and it is up to you whether to allow him to perform the operation or not. But if the veterinarian has had at least some successful experience in operations on rabbits, if you observe the doctor’s desire to work with your animal, if he intelligibly answers all the questions that concern you - why not?! The type of anesthesia the doctor is considering using - you are already familiar with the names of the most common anesthetics used on rabbits, and if your doctor is considering using a different drug, ask what the basis of his decision is and what experience the particular doctor has with using this drug.
Ask your veterinarian to tell you how the operation will be performed, whether premedication will be used, how the animal's condition will be monitored during and after the operation, and what analgesics will be used after the procedure.

The most common operations on rabbits

Sterilization - This is the complete removal of the uterus and ovaries of a female. Sterilization is carried out to avoid unwanted pregnancies, uterine cancer and to improve the behavior of the animal (eradicate " bad habits"rabbits). This operation can be performed from four months to two years. The risk of cancer of the reproductive organs increases greatly after two years of age.
Castration is the complete removal of a male's testicles. There are several methods for performing this operation. Castration is performed for birth control and behavior correction. Neutering also helps prevent testicular cancer, although cancer of the reproductive organs is more common in females.
Dental Procedures - Dental disease is common in rabbits and can be caused by poor diet, genetic disorders or injury. In some situations, a rabbit's teeth must be completely removed. Dental surgery is difficult primarily because the rabbit's mouth is very small and it is very difficult to see all the teeth. And also the roots of rabbits' teeth are very long. It is always better to carry out dental operations in a timely manner, when the problem first appears, in order to avoid further complications.
Removing Abscesses - Abscesses can appear on any part of a rabbit's body, but most often appear on the head. Most scalp abscesses are the result of dental disease. If possible, the abscess should be completely removed.
Gastrointestinal Surgeries - These surgeries are often performed to clear a blockage in the gastrointestinal tract. The blockage can occur in any part of the tract, and may be due to the accumulation of dry stomach contents, carpet threads, plastic, rubber, etc. Such operations on rabbits are very risky due to two factors:
1. Usually the rabbit is already in deep shock due to the blockage that has occurred.
2. The gastrointestinal tract of rabbits is a very delicate system. The gastrointestinal tract (particularly the cecum) may not function well after surgery. After such operations, adhesions are very often observed due to adhesive inflammation in the intestines, and the mechanical functioning of the intestines is often disrupted and blockage occurs again. Such patients require increased staff attention and the most careful monitoring. The first three days after surgery are critical, and the rabbit must remain in the clinic under the constant supervision of specialists.
However, a successful outcome from operations on the gastrointestinal tract is rare. Other surgeries - Surgeries can be performed on any organ in rabbits, just like in all other mammals.
Other common surgeries performed on rabbits are: cystotomy (opening Bladder, usually to remove a tumor or stones), orthopedic surgery, tumor removal. Your veterinarian can give you more information about these surgeries.

Razina A.V., Frolova A.I., Sergeev M.A.
Federal State Educational Institution of Higher Professional Education "Kazanskaya" state academy veterinary medicine them. N.E. Bauman"

The expansion of the species spectrum of animals kept at home (rabbits, rats, hamsters, ferrets, etc.) and the presence of surgical pathology in them requires the development of reliable pain relief when performing surgical interventions of varying duration and complexity with minimal impact on homeostasis.

Materials and methods

The experiments were carried out on 15 rabbits aged 6 months, which were divided according to the principle of analogues into 3 groups (5 animals in each).

For premedication, animals of the first group were injected with a 2% solution of xylosine hydrochloride (Rometar) intramuscularly at a dose of 4.0-6.0 mg/kg body weight, and then a 1% aqueous emulsion of propofol (Diprivan) was injected intravenously into the marginal vein of the ear at a dose of 5.0-7 .5 mg/kg body weight.

Animals of the second group were administered intravenously zoletil-50 at a dose of 6.6 mg/kg body weight

Animals of the third group were administered intramuscularly with rometar at a dose of 4.0-6.0 mg/kg, and 20 minutes later intramuscularly with zoletil-50 at a dose of 5-10 mg/kg.

Indicators of body temperature, pulse and respiration, characterizing the general clinical status of the animals, began to be determined before the introduction of anesthetics, and then after: after 10, 30, 60 minutes, 3 and 24 hours.

When determining the depth of anesthesia, the height of the amplitude of the chest excursion, the color of the mucous membrane of the oral cavity and tongue, the tone of the masticatory muscles, extensors and flexors of the joints of the extremities were taken into account, the degree of dilatation of the pupil, the severity of the pupil's reaction to changes in illumination and the corneal reflex (touching the conjunctiva, cornea) were assessed. ), degree of skin pain sensitivity (injection of a needle into the skin at the root of the tail, inner thigh, nose), conditioned reactions.

Heart rate was determined using a formula using an ECG recording. The number of beats per minute is 3000, divided by the distance between the two complexes in mm (Martin M..2004). Recording was carried out in the second lead with a paper speed of 50 mm/s from needle electrodes attached to the thoracic limbs in the shoulder area, and on the pelvic limbs in the thigh area.

Research results.

Group 1: 5 minutes after the administration of Rometar, the rabbits of the first group had a constriction of the pupil, the animals lowered their heads. Mild sedation and a moderate decrease in pain sensitivity were observed. But even when trying to give them a lateral position, the animals resisted.

10 minutes after premedication, sedation intensified, however, the animals showed quite active resistance to some manipulations associated with fixation in the lateral position.

5 minutes after intravenous administration of diprivan, the rabbits exhibited a pronounced relaxation of the muscles of the limbs, but the corneal reflex and pain sensitivity remained, which excluded the possibility of performing even minor surgical interventions. The animals began to move independently within 30-35 minutes after the administration of propofol.

Animals in this group showed a short-term slight increase in body temperature, and after the administration of Diprivan a decrease began: after 5 minutes by 0.8°C, after 30 minutes by 2.2°C, and after an hour by 2.3°C (Fig. 1).

In rabbits of this group, after premedication with Rometar, there was a decrease in heart rate to 156 beats/min, which is 35% lower than the initial data, which continued after the administration of propofol, and after 30 minutes a tendency toward gradual normalization of this indicator appeared (Fig. 2).

The described changes were accompanied by a decrease in breathing: 15 minutes after premedication, 10 breaths. dv/min, 5 minutes after administration of dpprivan for 18 breaths. bpm compared to the original value, which was 70 breaths. bpm. After 30 minutes, 48 ​​bpm were recorded. and only an hour later signs of the beginning recovery of the respiratory rate appeared (56 breaths per minute) (Fig. 3).

Subsequent studies showed that body temperature, pulse and respiratory rates 24 hours after an attempt to introduce rabbits into a state of general anesthesia using this method did not differ from those obtained before the start of drug administration.

Group 2: After intravenous administration of a 5% solution of zoletpla to the rabbits of the second group, instant muscle relaxation was observed. The corneal reflex and pain sensitivity were absent after 1 minute, but appeared again 5 minutes later. After an hour, the rabbits’ motor activity was restored, and after 1.5 hours they were already able to move independently.

When studying the indicators characterizing the clinical status of the experimental rabbits of this group, a decrease in body temperature was established, which began 5 minutes after the administration of Zoletil and after 30 minutes the body temperature was 1.2°C, and an hour later 1.6°C below the initial level (Fig.1).

After administration of the drug, a short-term increase in heart rate was recorded - after 10 minutes by 11 beats/min, which was replaced by a decrease (28 beats/min less than the initial value) (Fig. 2).

All described changes were accompanied by a decrease in the number of respiratory movements. 30 minutes after the administration of the zoletil solution, the depth and frequency of respiration began to recover, but the initial level, like all other indicators, was reached within a day (Fig. 3).

Group 3: After the administration of Rometar, all changes in the condition of the animals of the third group were similar to the changes found in the rabbits of the first group.

5 minutes after intramuscular administration of zoletil, complete muscle relaxation occurred, the corneal reflex and pain sensitivity were absent, and the pupil dilated.

On average for the group, after 30 minutes the corneal reflex and pain sensitivity were restored. After an hour, the animals tried to get up, and began to move independently 1.5 hours after the administration of Zoletil. The absence of pain sensitivity for 30 minutes allows you to perform operations such as ovariohysterectomy of females, castration of males, suturing wounds, etc.

After administration of zoletil, the rabbits began to experience a decrease in body temperature, which after 10 minutes was 0.4°C, after 30 minutes by 1.4°C, and after an hour by 2.5°C below the initial value (Fig. 1).

The decrease in pulse observed after the administration of Rometar, after the administration of Zoletil, was replaced by its gradual normalization (after 30 minutes - 172 beats/min), after which bradycardia was observed again (155 beats/min 1 hour after the start of introducing rabbits into a state of general anesthesia) (Fig. .2).

The described changes were accompanied by a decrease in breathing. The number of respiratory movements 30 minutes after the administration of zoletil became minimal (38 breaths per minute). Then the number of respiratory movements gradually increased and after 3 hours it was 76 per minute (Fig. 3).

Observations carried out after 24 hours showed that the general condition and food excitability of the rabbits, as well as their food intake, were good. Temperature, pulse and respiration data did not differ significantly from those established before the start of the study drugs.

Thus, the conducted studies allow us to consider the most optimal choice of the method carried out in animals of the third experimental group: general anesthesia of rabbits using Rometar for premedication, and against its background - Zoletil in the indicated doses.

magazine "Veterinary Clinic" No. 1 2008