Who among you has not had such experience: local or general anesthesia, so that the procedures you need do not cause pain? Would you prefer to have such manipulations performed on you without any anesthesia at all? I highly doubt it! Anesthesia is one of the most important achievements of modern medicine!
However, many people do not like to “lose control” of the situation, so they avoid general anesthesia. Others are afraid that they will not “wake up” from general anesthesia or that surgeons will make a mistake during the operation that will lead to new problems or death again.
Fortunately, these days with improved anesthetics, more competent staff (anesthesiologists, surgeons, etc.), smart devices, etc. anesthesia and operations have become safer than before.
As with any aspect of caring for your pet, the more you know about anesthesia and surgery, the better the decision you make. Anesthesia is the “scariest” topic for most rabbit owners. This is due to misinformation, myths and sometimes bad previous experiences. But if anesthesia is not allowed, it will be impossible to carry out many necessary operations, as well as certain diagnostics.
In this article we want to tell you about what happens to your rabbit during surgery, we will try to help you make the right decision. Myths about Rabbits Rabbits are weak animals - Over the past 25 years of practice with rabbits, we have learned that rabbits can tolerate most medical procedures as well as any other mammal. This myth stems mainly from the fact that in the past, owners could not notice their pet was unwell until the animal’s condition became critical. By the time people went to the vet, it was already too late. In addition, medications and treatments used on rabbits in the past have not always been perfect (due to veterinarians' lack of knowledge about treating rabbits).
Over the past 15 years, successful treatment and survival rates for rabbits have increased significantly - this is a consequence of the fact that rabbit owners have become more educated in the early diagnosis of ailments in their pets, and, as mentioned above, methods of treating animals have improved. Higher Risk of Anesthesia and Surgery - We do not believe that anesthesia or surgery is any more risky for rabbits than for other animals. The only exception is that rabbits tolerate operations on the gastrointestinal tract less well, which will be discussed below.
The myth about the high risk of anesthesia and operations comes from the past, when anesthetics used in veterinary medicine were not as safe as modern ones.
Effect of severe or prolonged stress
main reason The reason for which anesthesia should be used is pain relief. Pain can be a very stressful factor for a rabbit. A study of rabbits has shown what can happen to a rabbit due to severe or prolonged stress - drop in body temperature, drop in blood pressure, kidney damage, loss of appetite, stomach ulcers, cardiomyopathy, gastrointestinal stasis and death.
Anesthesia can relieve your rabbit of such problems by relieving the pain that is stress.
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 various 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 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 the abdominal cavity is opened 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 - the pressure of 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 detect disease in a rabbit. However, situations where, after a full examination, the disease remains undetected 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 lost 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 (by 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 from 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 the bladder, usually to remove tumors or stones), orthopedic surgery, and removal of tumors. Your veterinarian can give you more information about these surgeries.
However, many people do not like to “lose control” of the situation, so they avoid general anesthesia. Others are afraid that they will not “wake up” from general anesthesia or that surgeons will make a mistake during the operation that will lead to new problems or death again.
Fortunately, these days with improved anesthetics, more competent staff (anesthesiologists, surgeons, etc.), smart devices, etc. anesthesia and operations have become safer than before.
As with any aspect of caring for your pet, the more you know about anesthesia and surgery, the better the decision you make. Anesthesia is the “scariest” topic for most rabbit owners. This is due to misinformation, myths and sometimes bad previous experiences. But if anesthesia is not allowed, it will be impossible to carry out many necessary operations, as well as certain diagnostics.
In this article we want to tell you about what happens to your rabbit during surgery, we will try to help you make the right decision. Myths about Rabbits Rabbits are weak animals - Over the past 25 years of practice with rabbits, we have learned that rabbits can tolerate most medical procedures as well as any other mammal. This myth stems mainly from the fact that in the past, owners could not notice their pet was unwell until the animal’s condition became critical. By the time people went to the vet, it was already too late. In addition, medications and treatments used on rabbits in the past have not always been perfect (due to veterinarians' lack of knowledge about treating rabbits).
Over the past 15 years, successful treatment and survival rates for rabbits have increased significantly - this is a consequence of the fact that rabbit owners have become more educated in the early diagnosis of ailments in their pets, and, as mentioned above, methods of treating animals have improved. Higher Risk of Anesthesia and Surgery - We do not believe that anesthesia or surgery is any more risky for rabbits than for other animals. The only exception is that rabbits tolerate operations on the gastrointestinal tract less well, which will be discussed below.
The myth about the high risk of anesthesia and operations comes from the past, when anesthetics used in veterinary medicine were not as safe as modern ones.
Effect of severe or prolonged stress
The main reason anesthesia should be used is for pain relief. Pain can be a very stressful factor for a rabbit. A study of rabbits has shown what can happen to a rabbit due to severe or prolonged stress - drop in body temperature, drop in blood pressure, kidney damage, loss of appetite, stomach ulcers, cardiomyopathy, gastrointestinal stasis and death.
Anesthesia can relieve your rabbit of such problems by relieving the pain that is stress.
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 various 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 are the best choice for most surgeries. 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, is safe for rabbits with various types of 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 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 the abdominal cavity is opened 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 - the pressure of 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 detect disease in a rabbit. However, situations where, after a full examination, the disease remains undetected 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 lost 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 (by 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 from a female. Sterilization is carried out to avoid unwanted pregnancies, uterine cancer and to improve the behavior of the animal (eradicate the “bad habits” of the rabbit). 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 the bladder, usually to remove tumors or stones), orthopedic surgery, and removal of tumors. Your veterinarian can give you more information about these surgeries.
UDC 619:636.92:615.211
Injectable drugs and their combinations used for anesthesia in rabbits
Injectable drugs used to put rabbits under anesthesia during various diagnostic and therapeutic procedures. Their use is possible both independently and before inhalation drugs. Injection anesthesia, unlike inhalation anesthesia, does not require special equipment, for this reason many veterinarians are forced to use this method. Currently, various combinations of drugs for injection and inhalation anesthesia are more often used.
Accumulated experience shows that many drugs used for sedation, anesthesia and analgesia can be used for rabbits, but effective and safe doses of drugs, their pharmacodynamics, and the use of drug combinations have significant features. Below we describe some drugs and their combinations, the effect of which on the body of rabbits has been studied and which may be of interest to veterinarians in our country.
Acepromazine ( Acepromazine maleate) is a phenothiazine derivative that has a depressant effect on the central nervous system. It is a dopamine inhibitor, an alpha-adrenergic blocker with weak antimuscarinic activity. The main use of acepromazine in veterinary medicine is its tranquilizing effect, additional ones include antiarrhythmic effect and antispasmodic effect. It is commonly used for premedication in animals of many species. Acepromazine has a hypotensive effect and does not have analgesic activity. The dose for rabbits as a tranquilizer is 1 mg/kg IM, the effect should occur within 10 minutes and last 1-2 hours . Ghaffari MS et al., (2009) found that acepromazine in a usual dose reduces the production of tear fluid in rabbits . In rabbits, acepromazine can be used as premedication before gas anesthesia. It can be used in combination with butorphanol for better sedation.
Xylazine(Xylazine) - is an alpha 2-adrenergic receptor antagonist, has a moderate sedative and minor analgesic effect in rabbits. Causes relaxation of skeletal muscles through central action. Previously, it was used as a single drug or in combination with ketamine. This combination causes respiratory depression and of cardio-vascular system, and in high doses - cardiac arrhythmia and high mortality in rabbits. Atipamezole, an alpha adrenergic blocker, can be used as an antagonist to stop the action of xylazine.
Medetomidine(Medetomidine (Domitor, Pfizer) is a more specific alpha 2 agonist than xylazine, with fewer side effects. It is significantly more expensive and requires larger doses in rabbits than in other animal species. Medetomidine can be used as premedication or in combination with ketamine for surgical anesthesia... Medetomidine causes constriction of peripheral vessels, changing the blood supply to the mucous membranes, so that it can be mistakenly determined that the animal has cyanosis. When using medetomidine, hypoxia often develops, so that the use of oxygen is necessary throughout the entire period of anesthesia.
Medetomidine-induced vasoconstriction may interfere with pulse oximeter and venipuncture for blood collection and fluid resuscitation. This drug causes good laryngeal relaxation, facilitating endotracheal intubation. It does not cause respiratory depression and recovery usually occurs within three hours. Recovery can be accelerated by using atipamizole.
Butorphanol(Butorphanol) is a synthetic antagonist-agonist of opiate receptors. The analgesic effect is 3-5 times greater than the effect of morphine in humans and more than 30 times in rats. In rabbits, butorphanol causes analgesia and mild sedation, does not cause respiratory depression unless high doses are used . Used to relieve postoperative pain at a dose of 0.4 mg/kg orally every 4-6 hours. Several studies have shown that the use of high doses of butorphanol causes less analgesic effect than lower doses. The half-life of butorphanol in rabbits at a dose of 0.5 mg/kg is 1.64 hours after intravenous administration and 3.16 hours after subcutaneous administration. Butorphanol can be used to reverse the respiratory depressant effects of µ-agonists such as fentanyl, morphine and pephidine. Butorphanol (0.05 mg/kg subcutaneously or intramuscularly) is used in combination with medetomidine and ketamine for surgical anesthesia. It can also be used in combination with acepromazine for sedation . This combination causes vasodilation, which facilitates blood collection and intravenous injections.
Propofol(Propofol) is a short-acting hypnotic drug, not similar to drugs for general anesthesia, the mechanism of action is unclear . As a drug used to induce anesthesia, it has many advantages, including deep hypnotic effects and therapeutic breadth, rapid onset of action and rapid recovery. Repeated doses do not accumulate and propofol can be used to maintain anesthesia by continuous infusion. Baumgartner CM et al. (2009) for this purpose used propofol at a dose of 4.0-8.0 mg/kg intravenously, to maintain anesthesia 1.2-1.3 mg/kg/min . A dose of 5-14 mg/kg allows sufficient time for an experienced anesthesiologist to perform intubation. After administration, short-term apnea is possible, and when using high doses, respiratory arrest is possible.
Research by Dikmen B. et al. (2010) showed that the use of propofol is preferable to ketamine in animals with renal failure . Zhu T et al. (2008) found that propofol increases hepatic blood flow . According to Fudickar A. et al. (2009) administration of propofol causes such negative consequences as acute bradycardia, asystole, hyperlipemia and metabolic acidosis, rhabdomyolysis and myoglobinuria, which are described as Propofol infusion syndrome (PRIS). Propofol is not recommended for long-term anesthesia in rabbits. In the experiments of Chen WH et al. (2006) propofol had a direct effect on the heart of rabbits, causing a sharp decrease in blood pressure and bradycardia.
Ketamine(Ketamine) is a dissociative drug that is used alone to induce anesthesia or in combination with other drugs to induce and maintain anesthesia. Ketamine produces sympathomimetic effects that increase heart rate, cardiac output, and blood pressure. Intramuscular administration of 40 mg/kg ketamine over 6.0 +/- 0.5 minutes produced anesthesia lasting 36.0 +/- 0.9 minutes in rabbits. Preliminary intramuscular administration of vitamin C at a dose of 30, 60 and 240 mg/kg shortened the time of induction of anesthesia and prolonged anesthesia to 5.0 +/- 0.06 and 37.0 +/- 0.7; 4.0 +/- 0.5 and 39.0 +/- 0.6; 2.0 +/- 2.3 and 44.0 +/- 0.8 minutes respectively .
Studies have shown that ketamine administered intravenously at 10 mg/kg in rabbits with spinal cord injury protects against ischemia and reduces the decline in antioxidant levels. .
Ketamine does not eliminate the ocular, laryngeal, or swallowing reflexes. Poor muscle relaxation makes ketamine unsuitable for use as a single drug for anesthesia before surgery; it is used in combination with xylazine or other drugs. Ketamine/diazepam and ketamine/acepromazine combinations increase intraocular pressure in rabbits.
Tiletamine/zolazepam(tiletamine/zolazepame) - tiletamine is an injectable anesthetic, chemically similar to ketamine, zolazepam is a weak diazepine tranquilizer. The pharmacological action of the combination drug is similar to ketamine and diazepam. The suitability of tiletamine/zolazepam for anesthesia in rabbits was studied by Brammer DW et al. (1991). Intramuscular administration of 32 and 64 mg/kg of the drug did not cause anesthesia and led to a nephrotoxic effect with the development of renal failure within 5 days. The researchers concluded that this drug is contraindicated in rabbits. . The nephrotoxicity of tiletamine/zolazepam for rabbits was also established in a study by Doerning BJ. et al. (1992) Data on the inability of tiletamine/zolazepam to induce anesthesia in rabbits were obtained by Dupras J. et al. (2001) . At the same time, it is necessary to take into account the impossibility of legal use of many drugs used throughout the world in our country. If the veterinary clinic is not equipped to use inhalation anesthesia, and does not have permission to use ketamine, one of the few drugs of choice in this case remains tiletamine/zolazepam, which must be combined with other drugs.
Ketamine and xylazine.
For minimally invasive procedures lasting no more than 30-40 minutes, ketamine at a dose of 35 mg/kg mixed with xylazine 5 mg/kg is administered intramuscularly or subcutaneously . Once anesthetized, the rabbit can be intubated and, if necessary, connected to an artificial respiration apparatus. Maintaining anesthesia for up to 3 hours is ensured by intravenous administration of a ketamine/xylazine mixture (10+2 mg/kg).
Ketamine, xylazine and acepromazine.
Hobbs BA. et al. (1991) found that the combination of ketamine/xylazine with acepromazine is preferable if a prolonged operation is required; in their study, the anesthesia period was 60-120 minutes. But this combination, when administered intramuscularly, caused perineural inflammation and fibrosis in 4 out of 6 rabbits in a study conducted in 1999 by Vachon P. .
Medetomidine and ketamine.
A medetomidine/ketamine mixture at a dose of 0.35 mg/kg + 5 mg/kg administered intravenously provides surgical anesthesia lasting at least 35 minutes. Intravenous administration of atipamezole reverses the effect of these drugs. Studies conducted on rabbits (Kim MS et al. 2004) showed that an equal or double dose of atipamizole is optimal for reversing anesthesia .
Ketamine, medetomidine and isoflurane.
Ketamine at a dose of 15 mg/kg and medetomidine 0.25-0.5 mg/kg subcutaneously or intramuscularly in combination with isoflurane 1.5-2.0% provide a sufficient degree of anesthesia for orchiectomy and oophorectomy. Subcutaneous injection is easier to tolerate, but after intramuscular injection, induction of anesthesia occurs faster. Atipamezole is an effective antagonist, at a dose of 0.5-1.0 mg/kg, it acts faster when administered intramuscularly compared to subcutaneously and accelerates the recovery of the rabbit.
Ketamine and xylazine with butorphanol.
In a study by Marini RP et al. (1992) ketamine/xylazine at a dose of 35 mg/kg + 5 mg/kg was used together with butorphanol 0.1 mg/kg. The inclusion of butorphanol in this combination prolonged anesthesia by 1.4-1.6 times from 77 to 99 minutes. .
Medetomidine, ketamine and butorphanol with isoflurane.
A combination of medetomidine, ketamine, and butorphanol is used for short procedures such as incisor trimming or radiography. It can also be used to induce anesthesia before inhalational anesthesia is used for longer procedures such as molars, incisor extractions, in which intubation is necessary as the use of a face mask is not possible. We also recommend inhalation anesthesia when rinsing the lacrimal canal.
Medetomidine at a dose of 0.2 mg/kg in combination with 10 mg/kg ketamine and 0.5 mg/kg butorphanol is administered subcutaneously. This amounts to 0.2 mL/kg Domitor (Pfizer), 0.1 mL/kg ketamine, and 0.05 mL/kg Torbugesic (Fort Dodge). The injection is usually painful, the effect of the drugs begins in 5-10 minutes and lasts approximately 20 minutes. Full recovery occurs in 2-4 hours.
At the end of the operation, the effect of medetomidine can be reversed by atipamezole 1 mg/kg (0.1 ml/kg) (Antisedan (Pfizer). The period of action of atipamezole is 15-40 minutes. The analgesic effect of medetomidine is also relieved by atipamezole. If atipamezole is not administered, recovery after anesthesia occurs after 1-2 hours.
Tiletamine/zolazepam and xylazine.
Dupras J. et al. (2001) studied the possibility of using a combination of tiletamine/zolazepam at a dose of 20 mg/kg in combination with xylazine 3 mg/kg. with intramuscular injection. The induction of anesthesia lasted about 3 minutes, the duration of anesthesia averaged 109.4 minutes. Due to the ability of xylazine to cause significant hypoxia, researchers point to the obligatory provision of oxygen to the rabbit.
Razina A.V. et al. (2010) recommend intramuscular administration of Rometar at a dose of 4.0-6.0 mg/kg, followed (after 20 minutes) by intramuscular administration of tiletamine/zolazepam at a dose of 5-10 mg/kg. After 5 min. After intramuscular administration of zoletil, complete muscle relaxation occurred, the corneal reflex and pain sensitivity were absent, and the pupil dilated. Anesthesia lasted about 30 minutes, after 1.5 hours the rabbit moved independently.
Table - Drugs and their combinations recommended for sedation and anesthesia of rabbits
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Drugs |
Dose (mg/kg) |
Action |
Mode of application |
Duration of action |
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acepromazine |
sedation, does not cause analgesia |
|||
|
acepromazine + butorphanol |
sedation and analgesia |
|||
|
butorphanol + medetomidine + ketamine |
anesthesia |
20-30 minutes, recovery 1-4 hours |
||
|
ketamine + xylazine |
anesthesia |
30-40 minutes, recovery 1-2 hours |
||
|
ketamine + xylazine + butorphanol |
anesthesia |
40-60 minutes recovery 1-2 hours |
||
|
ketamine + xylazine + acepromazine |
anesthesia |
25-40 minutes, recovery 1-2 hours |
||
|
ketamine + acepromazine |
anesthesia |
|||
|
ketamine + medetomidine |
anesthesia |
at least 35 minutes |
||
|
propofol |
hypnotic |
to maintain anesthesia 1.2-1.3 mg/kg/min |
||
|
acepromazine + butorphanol + propofol |
sedation and analgesia |
to maintain anesthesia propofol 1.2-1.3 mg/kg/min |
||
|
tiletamine/zolazepam + xylazine |
anesthesia |
|||
|
xylazine + tiletamine/zolazepam |
anesthesia |
30 min, recovery 1.5 hours |
Thus, currently existing drugs and the possibility of their use in various combinations make it possible, in most cases, to choose the method of anesthesia in accordance with the condition of the rabbit, the nature and duration of the planned operation. In this case, the equipment of the veterinary clinic and the experience of the doctor play a significant role.
Candidate of Veterinary Sciences, Associate Professor of the Department of Diseases of Birds, Fish, Bees and Fur Animals, St. Petersburg State Academy of Veterinary Medicine, Center for Veterinary Medicine “Vetus”.
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Literature |
|
|
Plumb, Donald K. Pharmacological drugs in veterinary medicine // M., 2002. - 856 p. |
|
|
Razina A.V. Optimization of the method of general anesthesia in rabbits / A.V. Razina, A.I. Frolova, M.A. Sergeeva // Current issues in veterinary biology. - 2005. - No. 1 (5). - P. 32-35 |
|
|
Baumgartner CM, Koenighaus H, Ebner JK, Henke J, Schuster T, Erhardt WD. Cardiovascular effects of fentanyl and propofol on hemodynamic function in rabbits // Am J Vet Res. 2009 Mar;70(3):409-17. |
|
|
Brammer DW, Doerning BJ, Chrisp CE, Rush HG. Anesthetic and nephrotoxic effects of Telazol in New Zealand white rabbits // Lab Anim Sci. 1991 Oct;41(5):432-5. |
|
|
Cooper, J.E. Anaesthesia of exotic species. In Manual of Aneasthesia for Small Animal Practice // (A.D.R. Hilbery, ed.). British Small Animal Veterinary Association. 1989. - 144 r. |
|
|
Chang C, Uchiyama A, Ma L, Mashimo T, Fujino Y. A comparison of the effects on respiratory carbon dioxide response, arterial blood pressure, and heart rate of dexmedetomidine, propofol, and midazolam in sevoflurane-anesthetized rabbits // Anesth Analg. 2009 Jul;109(1):84-9. |
|
|
Chen WH, Lee CY, Hung KC, Yeh FC, Tseng CC, Shiau JM. The direct cardiac effect of propofol on intact isolated rabbit heart // Acta Anaesthesiol Taiwan. 2006 Mar;44(1):19-23. |
|
|
Cruz FS, Carregaro AB, Raiser AG, Zimmerman M. Total intravenous anesthesia with propofol and S(+)-ketamine in rabbits // Vet Anaesth Analg. 2010 Mar;37(2):116-22. |
|
|
Dikmen B, Yagmurdur H, Akgul T, Astarci M, Ustun H, Germiyanoglu C. Preventive effects of propofol and ketamine on renal injury in unilateral ureteral obstruction // J Anesth. 2010 Feb;24(1):73-80. |
|
|
Doerning BJ, Brammer DW, Chrisp CE et al: Nephrotoxicity of Tiletamine in New Zealand White rabbits // Lab Anim Sci, 1992; 42(3):267-269. |
|
|
Dupras J, Vachon P, Cuvelliez S, Blais D. Anesthesia of the New Zealand rabbit using the combination of tiletamine-zolazepam and ketamine-midazolam with or without xylazine // Can Vet J. 2001 Jun;42(6):455- 60. |
|
|
Elsa A, Ubandawaki S. Ketamine anesthesia following premedication of rabbits with vitamin C // J Vet Sci. 2005 Sep;6(3):239-41. |
|
|
Flecknell, P.A. The relief of pain in laboratory animals // Lab Anim., 1984; 18, 147-160. |
|
|
Flecknell, P.A. Anaesthesia // In Manual of Rabbit Medicine and Surgery. 2000; (P.A. Flecknell, ed.) pp. 103-116. |
|
|
Flecknell, P. A., John, M., Mitchell, M. et al. Neuroleptanalgesia in the rabbit // Lab Anim., 1983; 17, 104-109. |
|
|
Fudickar A, Bein B. Propofol infusion syndrome: update of clinical manifestation and pathophysiology // Minerva Anestesiol. 2009 May;75(5):339-44.). |
|
|
Ghaffari MS, Moghaddassi AP, Bokaie S. Effects of intramuscular acepromazine and diazepam on tear production in rabbits // Vet Rec. 2009 Jan 31;164(5):147-8. |
|
|
Ghaffari MS, Moghaddassi AP. Effects of ketamine-diazepam and ketamine-acepromazine combinations on intraocular pressure in rabbits // Vet Anaesth Analg. 2010 May;37(3):269-72. |
|
|
Hellebrekers, L.J., de Boer, E.J., van Zuylen, M.A., Vosmeer H. A comparison between medetomidine-ketamine and medetomidine-propofol anaesthesia in rabbits // Lab Anim., 1997; 31, 58-69. |
|
|
Hobbs BA, Rolhall TG, Sprenkel TL, Anthony KL. Comparison of several combinations for anesthesia in rabbits // Am J Vet Res. 1991 May;52(5):669-74. |
|
|
Kim MS, Jeong SM, Park JH, Nam TC, Seo KM. Reversal of medetomidine-ketamine combination anesthesia in rabbits by atipamezole // Exp Anim. 2004 Oct;53(5):423-8. |
|
|
Marini RP, Avison DL, Corning BF, Lipman NS. Ketamine/xylazine/butorphanol: a new anesthetic combination for rabbits // Lab Anim Sci. 1992 Feb;42(1):57-62. |
|
|
Martinez MA, Murison PJ, Love E. Induction of anaesthesia with either midazolam or propofol in rabbits premedicated with fentanyl/fluanisone // Vet Rec. 2009 Jun 27;164(26):803-6. |
|
|
Mason D.E. Anesthesia, analgesia, and sedation for small mammals // In Ferrets, Rabbits and Rodents, Clinical Medicine and Surgery. (E.V. Hillyer, K.E. Quesenberry, eds). 1997. - pp. 378-391. |
|
|
Murphi KL, Roughan JV, Baxter MG, Flecknell PA. Anaesthesia with a combination of ketamine and medetomidine in the rabbit: effect of premedication with buprenorphine // Vet Anaesth Analg. 2010 May;37(3):222-9. Epub 2010 Mar 10. |
|
|
Ohya M, Taguchi H, Mima M, Koumoto K, Fukae T, Uchida M. Effects of morphine, buprenorphine and butorphanol on airway dynamics of the rabbit // Masui. 1993 Apr;42(4):498-503. |
|
|
Orr HE, Roughan JV, Flecknell PA. Assessment of ketamine and medetomidine anaesthesia in the domestic rabbit // Vet Anaesth Analg. 2005 Sep;32(5):271-9. |
|
|
Portnoy, L.G., Hustead, D.R. Pharmacokinetics of butorphanol tartrate in rabbits // Am J Vet Res., 1992; 53, 541. |
|
|
Stephen J. Birchard, Robert G. Sherding - Saunders Manual of Small Animal Practice, Third Edition, 2005.- 2008 p. |
|
|
Vachon P. Self mutilation in rabbits following intramuscular ketamine-xylazine-acepromazine injections // Can Vet J. 1999 Aug;40(8):581-2. |
|
|
Wixson, S.K. Anesthesia and analgesia. In The Biology of the Laboratory Rabbit, Academic Press, 2nd edn. 1994 (P.J. Manning and D.H. Ringler, eds). pp 87-109. |
|
|
Yershov AL, Jordan BS, Fudge JM, Dubick MA. Influence of the mode of ventilation on ketamine/xylazine requirements in rabbits // Vet Anaesth Analg. 2007 May;34(3):157-63. |
|
|
Yu QJ, Zhou QS, Huang HB, Wang YL, Tian SF, Duan DM. Protective effect of ketamine on ischemic spinal cord injury in rabbits // Ann Vasc Surg. 2008 May-Jun;22(3):432-9. |
|
|
Zhu T, Pang Q, McCluskey SA, Luo C. Effect of propofol on hepatic blood flow and oxygen balance in rabbits // Can J Anaesth. 2008 Jun;55(6):364-70. |
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Significant biological characteristics of rabbits, which distinguish them from other domestic animals, must be taken into account in the postoperative period. To recover from anesthesia, the rabbit is placed on a warm bedding or in a heated cage with a heated floor (Fig. 1, 3), a temperature of about 35˚C is required. As soon as the rabbit's body temperature has stabilized and the rabbit can sit on its paws, the heating must be reduced to 26-28˚C, since rabbits in this state cannot breathe often and are sensitive to hyperthermia. The absence of external irritants and comfortable environmental conditions facilitate recovery after anesthesia. Only a fully awakened rabbit can be kept at room temperature.
For keeping, it is best to choose a room where there are no other animals and there is no smell of them. Once the rabbit has recovered enough to eat and drink, it is necessary to provide it with water and food. Immediately after waking up and throughout the postoperative period, it is preferable to give hay, grass, and carrots. After extraction of the incisors, it is necessary to give the rabbit soft, pureed or grated food. Good quality hay can also be used as bedding to give your rabbit a saddle position (Figure 2).
Good surgical technique, speed of operation and suitable suture material reduce discomfort in the area of the surgical wound, but in most cases postoperative analgesia is required. Assessing pain in rabbits can be difficult because they do not show many of the signs of pain seen in other species and sit quietly near the back of the cage, unresponsive to their surroundings. Rabbits are extremely sensitive to pain, especially after abdominal surgery and incisor removal. Pain and stress stimulate the sympathetic nervous system and reduce gastrointestinal motility. Decreased intestinal motility is the trigger for the development of a cascade of adverse processes that lead to liver lipidosis and death.
The presence of pain can be determined by observing the animal, but this requires close communication with it before surgery and knowledge of the characteristics of its behavior. Physiological parameters such as body temperature, heart rate and respiration change under the influence of pain, but to determine these parameters it is necessary to remove the rabbit from the cage, which in itself can cause them to change. Rabbits in pain will not approach the front wall of the cage when they see food. They do not groom their fur and can become aggressive towards other animals kept in the same cage. Abdominal pain may be manifested by bending over and grinding teeth. Sometimes rabbits behave restlessly, periodically jumping up and spinning around the bottom of the cage. The consequence of pain is a complete refusal to feed.
Analgesia in laboratory animals, including rabbits, has been studied to a considerable extent. A pain rating system has been developed to determine the effectiveness of analgesics, although individual characteristics may influence the perception of pain, especially of moderate intensity. The dosage of drugs required to provide analgesia depends on the stimulus, so it is necessary to monitor the rabbit and determine its response to analgesia. Pain is a life-threatening condition for the rabbit, so all rabbits in pain should be provided with analgesia.
Analgesia is “the absence of pain sensitivity or relief of pain without loss of consciousness.” In response to pain and other stressors, endogenous opioids are released and reduce pain sensitivity. Inflammation or hypoxia at the site of injury leads to the release of nociceptive substances such as kinins, which in turn stimulate the formation of prostaglandins.
Opioid analgesics are centrally acting drugs used for severe pain and have a specific effect on the central nervous system. Pharmacological effects are associated with the effect on opioid receptors in the central nervous system. A variety of opioid receptors are found in the brain, spinal cord and other tissues, including the gastrointestinal tract. Opioids cause a specific effect depending on the type of receptor, and there are species differences in their action:
– µ- (mu) receptors are mainly responsible for supraspinal analgesia, euphoria, respiratory depression and cause physical dependence in humans;
– k-(kappa) receptors are mainly responsible for spinal analgesia, miosis and sedation;
– σ- (sigma) receptors are responsible for dysphoria (sullen, grouchy, irritable, angry mood with increased anxiety in response to any external stimulus), hallucinations, respiratory agitation and various vasomotor effects.
Other receptors, such as δ (delta) receptors, are present in various tissues. The effects on the µ- and κ-receptors are most important for pain relief.
Other effects, such as respiratory depression, sedation, or effects on gastrointestinal motility, may or may not be beneficial depending on the situation in which these drugs are used.
In rabbits, narcotic analgesics are used to provide analgesia and, in some cases, anesthesia. They can also be used after anesthesia to prolong the analgesic effect. On the other hand, narcotic analgesics cause respiratory and mental depression, hypothermia and bradycardia in rabbits.
Buprenorphine is a strong, long-acting analgesic and partial opioid agonist. In rabbits, it is used for long-term analgesia to eliminate acute or chronic pain in the internal organs at a dose of 0.02-0.05 mg/kg orally or intramuscularly every 6-12 hours; 0.5 mg/kg rectally every 12 hours. Buprenorphine is also used to prevent the respiratory depressant effects of fentanyl after surgery when a fentanyl/fluanisone combination and benzodiazepines are used for anesthesia.
Butorphanol is a synthetic agonist-antagonist of opioid receptors. In rabbits, butorphanol provides analgesia and mild sedation and does not cause respiratory depression unless high doses are used. Used to relieve postoperative pain at a dose of 0.4 mg/kg orally every 4-6 hours.
Research has proven that the use of high doses of butorphanol causes less analgesic effect than lower doses. The half-life of butorphanol in rabbits at a dose of 0.5 mg/kg is 1.64 hours after intravenous administration and 3.16 hours after subcutaneous administration. Butorphanol can be used to reverse the respiratory depressant effects of μ-agonists such as fentanyl, morphine, and pephidine.
Tramadol is an opioid analgesic, a derivative of cyclohexanol. Non-selective agonist of µ-, δ- and K-receptors in the central nervous system. It is a racemate of (+) and (-) isomers (50% each), which are involved in various ways in the analgesic effect. The (+) isomer is a pure opioid receptor agonist, has low tropism and does not have pronounced selectivity for various receptor subtypes. The (-) isomer, inhibiting the neuronal uptake of norepinephrine, activates descending noradrenergic influences. Due to this, the transmission of pain impulses to the gelatinous substance of the spinal cord is disrupted, which causes a sedative effect. In therapeutic doses it practically does not depress breathing. Has an antitussive effect. More than 80% of tramadol is excreted through the kidneys in rabbits. After oral administration of tramadol at a dose of 11 mg/kg, no side effects occurred. The half-life was 145.4 +/- 81.0 minutes; maximum concentration in blood plasma 135.3 +/- 89.1 ng/ml. The recommended dose for rabbits is 2.0-4.0 mg/kg every 12 hours.
Fentanyl/fluanisone. Fentanyl is a potent opioid agonist that acts predominantly at the μ receptor and produces analgesia, respiratory depression and, in humans, euphoria. The analgesic effect is 20-100 times greater than morphine. Its analgesic effect is enhanced by fluanisone, which also relieves the depressant effect on breathing. According to many authors, this is the best drug used in rabbits for sedation and anesthesia; deep analgesia lasts 3 hours after administration. The fentanyl/fluanisone combination is used for premedication, sedation and potent analgesia or, in combination with midazolam, for anesthesia.
In some cases, nonsteroidal anti-inflammatory drugs (NSAIDs), which inhibit the synthesis of cyclooxygenase, prostaglandins and related substances, may be an alternative to opioid analgesics. Cyclooxygenase is an enzyme that promotes the formation of prostaglandins from arachidonic acid in cell membranes. There are two isomers of cyclooxygenase: COX-1 and COX-2. All NSAIDs have analgesic, antipyretic and anti-inflammatory properties. Their potential toxic effect is associated with cyclooxygenase isomers. COX-1 has a number of physiological properties, and inhibition of COX-1 is thought to be responsible for most of the toxic effects of NSAIDs. COX-2 is produced at sites of inflammation by inflammatory mediators.
Carprofen inhibits cyclooxygenase less and is therefore less toxic; it has a different mechanism of action. The structure of the molecule also affects the pharmacological action, especially of NSAIDs belonging to the 2-arylproprionic acid subgroup (propionic acid derivatives: carprofen, ketoprofen and vedaprofen). Some animal species have different metabolisms. In general, the dosing interval for NSAIDs in neonates and older animals should be longer to reduce toxicity.
Inhibition of normal regulation by prostaglandins can lead to insufficient renal perfusion in hypotensive patients and to acute renal failure. This happens during anesthesia, especially if there is significant blood loss, then blood pressure should be maintained by administering the required amount of solutions. It is advisable to take a 24-hour break between the use of different types of NSAIDs.
NSAIDs can be used for postoperative analgesia and the treatment of chronic osteoarthritis. The effect of NSAIDs on prostaglandin synthesis in rabbits is significant. Prostaglandins stimulate soft feces in rabbits by inhibiting proximal intestinal motility and stimulating distal intestinal motility.
Aspirin inhibits cyclooxygenase, which leads to a decrease in the synthesis of prostaglandins and thromboxants, reduces platelet aggregation and inflammation. Aspirin is an effective analgesic for rabbits, it is used as a first aid remedy, which is why many rabbit owners have it in their home. The oral dose is 100 mg/kg. The maximum concentration in the blood serum of rabbits is achieved after 1-2 hours. Aspirin may cause a decrease in platelet counts and a tendency to bleed in laboratory rabbits. The analgesic properties are weaker compared to some other NSAIDs, such as carprofen and flunixin.
Carprofen is a weak cyclooxygenase inhibitor with a low COX-1:COX-2 ratio and minimal toxic effect. Carprofen, due to its availability, can be prescribed after surgery to all patients. Although it can be administered orally (1.5 mg/kg twice daily), studies have shown that it is best administered subcutaneously or intravenously (2-4 mg/kg once daily).
When administered subcutaneously, adverse effects may occur due to possible penetration of the drug into the dermis. To reduce the number of complications, you need to be sure that the drug has entered the subcutaneous tissue and not the dermis, and massage the area where the drug was administered after the injection. Carprofen is especially indicated for acute pain after fractures and injuries.
Flunixin is a potent cyclooxygenase inhibitor that has been successfully used as an anti-inflammatory agent in cows and horses. Manufacturers do not recommend its use until the patient has fully recovered from general anesthesia because this NSAID may result in decreased renal blood flow. It also cannot be used concomitantly with other nephrotoxic drugs such as gentamicin. Flunixin can be used as an analgesic and anti-inflammatory drug in rabbits at a dose of 1.1 mg/kg 2 times a day, subcutaneously.
The possibility of using cyclooxygenase inhibitors for the treatment of enterotoxemia is of interest. Elmas M. et al. (2008) successfully used 2.2 mg/kg flunixin and 5 mg/kg enrofloxacin intravenously for this purpose.
Ketoprofen. Ketoprofen has been described in small mammals, including rabbits, and is an alternative to carprofen and meloxicam. Administered orally, twice a day, at a dose of 1-3 mg/kg.
Meloxicam is an NSAID with a low COX-1:COX-2 ratio. It has a strong anti-arthritic effect and is less likely to cause gastric irritation in animals than other NSAIDs. Studies of its toxicity have shown good tolerance and excellent resistance to it in rabbit tissue.
Gastric emptying of this drug and intestinal transport are not affected by therapeutic doses of meloxicam, with the exception of a short-term effect on gastric acidity. Doses significantly higher than those recommended for anti-inflammatory effects did not affect the excretion of water, electrolytes and creatinine throughout the observation period. After a single oral dose of meloxicam at a dose of 0.3 and 1.5 mg/kg, the maximum concentration of the drug in plasma was reached after 6-8 hours and amounted to 0.14 and 3.0 μg/ml, respectively, decreasing to an undetectable level within 24 hours. When using the drug for five days, no accumulation was observed; to achieve the required therapeutic concentration when used once a day, doses exceeding 0.3 mg/kg are required. In rabbits, the drug can be given with flower honey for long-term analgesia for painful conditions such as arthritis or spondylosis at a dose of 0.1-0.2 mg/kg every 12 hours.
Carpenter J. W. et al. (2009), studying the pharmacokinetics of meloxicam in rabbits, found that oral use of the drug at a dose of 0.2-0.3 mg/kg once a day was sufficient, and found no side effects when using it for 10 days. The maximum concentration of the drug in plasma on the first day was 0.17 mcg/kg, on the 10th day – 0.24 mcg/kg. In addition, Salhab A. S. et al. (2001) found that meloxicam at a dose of 20 mg/kg intraperitoneally inhibits ovulation in rabbits when administered 2 and 5 hours after coitus.
NSAIDs are selected based on their analgesic and anti-inflammatory activity. Drugs such as flunixin and carprofen provide analgesic effects comparable to opioid analgesics. Leach M. C. et al. (2009) studied the effect of pain and stress on the behavior of rabbits after ovariohysterectomy and the possibility of using meloxicam in the postoperative period. It was found that for sufficient analgesia in case of soft tissue damage, a rabbit requires large doses of the drug (initial dose - 1 mg/kg, subsequent dose - 0.5 mg/kg/day) or a combination of meloxicam with opioid analgesics.
Cooper C. S. et al. (2009) compared the effects of meloxicam and buprenorphine on the appetite of rabbits for 7 days after surgery, the amount of feces and urine, body weight and level of analgesia and concluded that meloxicam is a good alternative to buprenorphine and with its use the risk of developing anorexia and gastrointestinal stasis minimal.
To ensure adequate anesthesia, opioid analgesics and NSAIDs can be used simultaneously with minimal risk of side effects.
When a rabbit is released from the hospital, the owner is instructed to carefully monitor the pet’s behavior, food intake and excretion of solid feces. The rabbit must be brought in for re-examination if it has not eaten for more than 24 hours. If the rabbit owner is not sure that the rabbit is eating or its appetite is reduced, it is necessary to hospitalize the animal for further observation. A rabbit that does not begin to eat after surgery needs treatment to prevent or reverse gastrointestinal stasis and a review of postoperative orders.
Literature
List
- Plumb, Donald K. Pharmacological drugs in veterinary medicine // M., 2002. – 856 p.
- Aeschbacher, G. Rabbit anesthesia // Compendium on Continuing Education, 1995, 17, 1003-1011.
- Carpenter J. W., Pollock C. G., Koch D. E., Hunter R. P. Single and multiple-dose pharmacokinetics of meloxicam after oral administration to the rabbit (Oryctolagus cuniculus) // J Zoo Wildl Med. 2009 Dec; 40(4): 601-6.
- Cooper C. S., Metcalf-Pate K. A., Barat C. E., Cook J. A., Scorpio D. G. Comparison of side effects between buprenorphine and meloxicam used postoperatively in Dutch belted rabbits (Oryctolagus cuniculus) // J Am Assoc Lab Anim Sci. May 2009; 48(3): 279-85.
- Elmas M., Yazar E., Uney K., Er Karabacak A., Traş B. Pharmacokinetics of enrofloxacin and flunixin meglumine and interactions between both drugs after intravenous co-administration in healthy and endotoxaemic rabbits // Vet J. 2008 Sep; 177(3): 418-24. Epub 2007 Jul 17.
- Fujibayashi K., Sakamoto K., Watanabe M., Iizuka Y. Pharmacological properties of R-84760, a novel kappa-opioid receptor agonist // Eur J Pharmacol. 1994 Aug 11; 261(1-2): 133-40.
- Flecknell P. A. The relief of pain in laboratory animals // Lab Anim., 1984; 18, 147-160.
- Flecknell P. A. Analgesia in small mammals // Sem Avian Exotic Pet Med., 1998; 7, 41-47.
- Flecknell P. A., Liles J. H., Wootton R. Reversal of fentanyl/fluanisone neuroleptanalgesia in the rabbit using mixed agonist/antagonist opioids // Lab Anim. 1989 Apr; 23(2): 147-55.
- Green C. J. Neuroleptanalgesic drug combinations in the anaesthetic management of small laboratory animals // Lab Anim., 1975; 9, 161–178.
- Hawkins M. G., Taylor I. T., Craigmill A. L., Tell L. A. Enantioselective pharmacokinetics of racemic carprofen in New Zealand white rabbits // J Vet Pharmacol Ther. 2008 Oct; 31(5): 423-30.
- Hayashida M., Fukunaga A., Fukuda K., Yamazaki S. Y., Arita H., Hanaoka K. A rabbit model for evaluation of surgical anesthesia and analgesia: characterization and validation with isoflurane anesthesia and fentanyl analgesia // J Anesth. 2004; 18(4): 282-91.
- Hubbell J. A., Muir W. W. Evaluation of a survey of the diplomates of the American College of Laboratory Animal Medicine on the use of analgesic agents in animals used in biomedical research // J Am Vet Med Assoc. 1996 Sep 1; 209(5): 918-21.
- Jenkins W. L. Pharmacologic aspects of analgesic drugs in animals: an overview // J Am Vet Med Assoc., 1987; 191, 1231–1240.
- Karachalios T., Boursinos L., Poultsides L., Khaldi L., Malizos K. N. The effects of the short-term administration of low therapeutic doses of anti-COX-2 agents on the healing of fracture // An experimental study in rabbits. J Bone Joint Surg Br. 2007 Sep; 89(9): 1253-60.
- Leach M. C., Allweiler S., Richardson C., Roughan J. V., Narbe R., Flecknell P. A. Behavioral effects of ovariohysterectomy and oral administration of meloxicam in laboratory housed rabbits // Res Vet Sci. 2009 Oct; 87(2): 336-47. Epub 2009 Mar 19.
- Lintz W., Erlaçin S., Frankus E., Uragg H. Biotransformation of tramadol in man and animal Arzneimittelforschung. 1981; 31(11): 1932-43.
- Miyazaki Y., Horii Y., Ikenaga N., Shimoda M., Kokue E. Possible active transport mechanism in pharmacokinetics of flunixin-meglumine in rabbits // J Vet Med Sci. 2001 Aug; 63(8): 885-8.
- Ohya M., Taguchi H., Mima M., Koumoto K., Fukae T., Uchida M. Effects of morphine, buprenorphine and butorphanol on airway dynamics of the rabbit // Masui. 1993 Apr; 42(4): 498-503.
- Osterloh G., Friderichs E., Felgenhauer F., Günzler W. A., Henmi Z., Kitano T., Nakamura M., Hayashi H., Ishii I. General pharmacological studies on tramadol, a potent analgesic agent Arzneimittelforschung. 1978; 28(1a): 135-51.
- Portnoy L. G., Hustead D. R. Pharmacokinetics of butorphanol tartrate in rabbits // Am J Vet Res., 1992; 53, 541.
- Richardson V. C. G. Rabbits Health, Husbandry and Diseases. Blackwell Science Ltd, 2000. – 178 rub.
- Salhab A. S., Gharaibeh M. N., Shomaf M. S., Amro B. I. Meloxicam inhibits rabbit ovulation // Contraception. 2001 Jun; 63(6): 329-33.
- Small Animal Clinical Pharmacology / Jill Maddison et al. – Elsevier Limited, 2008. – 589 p.
- Stephen J. Birchard, Robert G. Sherding – Saunders Manual of Small Animal Practice, Third Edition, 2005. – 2008 p.
- Souza M. J., Greenacre C. B., Cox S. K. Pharmacokinetics of orally administered tramadol in domestic rabbits (Oryctolagus cuniculus). Am J Vet Res. 2008 Aug; 69(8): 979-82
- Turner P. V., Chen H. C., Taylor W. M. Pharmacokinetics of meloxicam in rabbits after single and repeat oral dosing // Comp Med. Feb 2006; 56(1): 63-7.
- Turner P. V., Kerr C. L., Healy A. J., Taylor W. M. Effect of meloxicam and butorphanol on minimum alveolar concentration of isoflurane in rabbits // Am J Vet Res. May 2006; 67(5): 770-4.
- Wixson S. K. Anesthesia and analgesia. In The Biology of the Laboratory Rabbit, Academic Press, 2nd edn. 1994 (P. J. Manning and D. H. Ringler, eds). pp. 87–109.