How anesthesia is used in feline surgery?
However, since conditions such as gingivitis and feline periodontal disease require anesthesia to treat, cat owners are often concerned and want to learn more about the process.
So, what happens when your cat has a general anesthetic, and are you right to be worried?
Pre-procedure tests before feline surgery
Before your cat undergoes a dental procedure, the vet will carry out several tests to check for any existing health problems that could affect your cat’s suitability for general anesthesia.
First, the vet will conduct a general physical exam. Based upon the exam, other tests relevant to your cat’s age, medical history, and breed may be performed, such as a complete blood count (CBC), a thyroid test, a chemistry profile, a urinalysis, and an ECG or ultrasound if your cat’s heart has abnormal beats.
The test results will enable the vet to choose the safest, most appropriate and correct dose of drugs to use during your cat’s procedure.
You will be given the relevant consent paperwork to complete before the tests are undertaken. This is your opportunity to pose any questions that you have about the procedure or to voice your concerns.
Preparation for feline general anesthesia
Your veterinarian will inform you how long your cat should fast before bringing him in for the procedure. Initially, your cat will be given a sedative to relieve anxiety and to alleviate any discomfort.
An intravenous catheter is used to administer injectable anesthetics and fluids directly into the bloodstream and is also available in case emergency medication is required during the procedure.
Cats will often receive an intravenous anesthetic, followed by a gas anesthetic. Once your cat is anesthetized, an endotracheal tube will be placed in his trachea to protect their airway and to administer the gas that ensures he stays unconscious throughout the procedure.
Before, during, and after general anesthesia, intravenous fluids will be given to your cat to help keep his vital organs and kidneys hydrated and to help with blood pressure maintenance.
Monitoring of your cat
Throughout your cat’s procedure, his vital signs will be closely monitored by a veterinary technician to ensure that he is doing well. Monitoring is essential to ensure your cat’s safety throughout the dental procedure.
Feline heart rate and rhythm
Your cat’s heart will be monitored to ensure that the rate and rhythm remain within normal parameters. An electrocardiogram (ECG, EKG) is often used for this purpose.
An EKG measures the electrical impulses that the heart generates, allowing early recognition of any changes to the heart rhythm and rate. Alternatively, an esophageal stethoscope may be used.
This is a simple device placed down your cat’s esophagus to the level of his heart. The sound of the heart is then amplified through a speaker, allowing changes in rate or rhythm to be detected.
Feline blood pressure and flow
Efficient tissue perfusion is essential for your cat’s well-being during the procedure. Tissue perfusion refers to the movement of blood through the vessels in your cat’s organs.
Perfusion is monitored by the measurement of capillary refill time (CRT). CRT is assessed by applying gentle pressure to your cat’s gums so that they turn pale, and then observing how long it takes for the gum color to return to normal.
With good tissue perfusion, CRT should take about one second. Most importantly, your cat’s blood pressure is also closely monitored to help determine the depth of anesthesia and tissue perfusion.
Feline oxygen saturation
Pulse oximetry will be performed to ensure that your cat’s blood contains sufficient oxygen. A sensory probe is clipped to any area of superficial vascularization such as the pink, unpigmented area of your cat’s tongue, a paw, etc., and the color of the mucous membranes is measured. Pink membranes normally indicate good oxygen saturation.
Feline respiratory rate
Your cat’s breathing and respiratory system function is monitored by observing the chest wall and counting the number of breaths that are taken per minute. Further, the movement of the reservoir bag on the gas anesthetic machine is monitored.
Feline temperature
Your cat’s body temperature will drop slightly while under anesthetic. Your cat will be kept warm during the procedure with heat pads and blankets, and his temperature will be monitored closely.
Depth of feline anesthesia
Throughout the procedure, the anesthetist will watch your cat closely for signs that might indicate that the anesthesia needs adjustment. These checks are made via visual observations, including pupil position, certain reflexes, and muscle relaxation.
General anesthesia for cats
General anesthesia is used to keep your cat from moving while the procedure is carried out, to prevent pain, and to encourage muscle relaxation. General gas anesthetics that are commonly used include halothane and isoflurane. Isoflurane is preferred when treating older cats, as it places less strain on the heart and other organs, and is deemed to be safer.
There are two main types of gas anesthesia systems in use in small-animal practices: non-rebreathing and rebreathing. Both require close monitoring.
Rebreathing gas anesthesia systems for cats
Rebreathing systems or partial rebreathing systems are generally used for healthy cats. Each breath administered by the system contains exhaled gas for which the carbon dioxide content has been removed and replaced by oxygen and anesthetic.
Rebreathing systems offer a number of advantages: Less anesthetic gases and oxygen are used because of lower flow rates, less waste gases are produced, and your cat’s moisture and heat from respirations are conserved.
Non-rebreathing gas anesthesia systems for cats
Non-rebreathing gas anesthesia systems are typically used on cats that weigh less than 10 pounds. Smaller animals require a higher gas flow to prevent them from rebreathing carbon dioxide. T
his system sees little to no exhaled gases retuned to your cat, being removed instead by the system. The gas anesthesia machine mixes the anesthetic gas with oxygen and delivers it to your cat via the endotracheal tube. The gas then moves across the lungs until it reaches the alveoli.
The gas is then transferred through the alveoli into the bloodstream and onward to the brain, where the state of anesthesia is achieved. To decrease the depth of anesthesia during the procedure or to awaken your cat, the process is reversed.
Feline recovery from general anesthesia
After the procedure, your cat will be placed somewhere warm and quiet, but under observation, while recovering from the anesthesia. Ideally, he should awaken slowly and quietly.
Urination and vomiting is not uncommon as your cat comes round from the anesthetic, and shivering is quite normal as the body’s temperature regulation mechanism stabilizes.
While he recovers, your cat’s vital signs will be closely monitored. Following routine dental procedures, most cats are ready to go home after four to eight hours.
If your cat is having teeth removed or will be in discomfort when he wakes up, your vet will give pain-relieving medication immediately following the procedure so that it is already working when your cat wakes up. Other medications will be given as required on a case by case basis. If your cat is pawing at his mouth, an Elizabethan collar may be fitted.
Your cat may feel nauseous and sleepy for 24 hours following the procedure. Allow him to sleep off the anesthetic, and be sure that he has fresh water readily available.
Your cat may need to be monitored overnight at the veterinarian’s office or emergency hospital if any complication arises.
Feline anesthesia facts
- General anesthesia is used for most feline dental procedures.
- Your cat’s vital signs will be closely monitored throughout his anesthesia.
- Although no surgical procedure is 100% risk free, feline anesthesia is very safe overall!
