What you need to know about your older pet and anesthesia

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When an older pet goes under anesthesia it can cause a great amount of anxiety for both the owner and veterinarian involved. A common question I get from clients when their pet are about to go under anesthesia is: “Will they wake up?”. This concern leads to many owners electing not to go ahead with many procedures that may be necessary to improve the health of the pet. Why are older pets more at risk for problems with anesthesia? What recommendations should you as an owner consider prior to having your pet go under anesthesia? How do you decide when it is worth the risk for your pet to undergo a procedure? What questions do you need to ask your veterinarian regarding anesthesia and your older pet? We will examine these questions and much more through this article.

Why are older pets more at risk with anesthesia?

Compared to younger animals, older pets are more at risk for complications with anesthetic procedures. A pet is considered elderly when it has reached over 60% of their average lifespan. For most pets this means being the age of 7 years or older. Having an older animal does not mean a guaranteed death sentence if your pet has to go under anesthesia. However, with aging there is an increased chance of chronic diseases such as kidney or heart disease. Older pets can also experience a decline in organ function that may affect their response to anesthetic drugs. Below are a list of organs involved in anesthesia and an explanation how age can alter their function:

The heart

The heart plays an important role with anesthesia by adjusting its rhythm and rate when changes in blood pressure occur. Changes in blood pressure are common during anesthesia. Often the blood pressure will decrease and the heart will compensate by beating faster. In older animals this response to blood pressure may be slower or non-existen therefore not allowing adequate compensation.

The brain

Older dogs may have a reduced brain function resulting in a slower response to changes from anesthesia. The main concern with this is the ability to maintain temperature during the anesthetic procedure. Since this may be impaired in older animals, they are more at risk of their temperature becoming too low.

The kidneys

These organs play a very important role in metabolizing many of the anesthetic agents used during procedures. Metabolism of anesthetic agents are vital for the recovery period for the pet. As I mentioned before, older animals are more at risk of having impaired kidney function. Therefore, they are more at risk of having a slower or more difficult recovery.

The liver

Elderly pets may have some loss of liver function. The liver serves an important function of breaking down anesthetic drugs through enzymes and filtering drugs out of the blood. Therefore, an impaired liver function can lead to a prolonged action of drugs and a longer recovery.

The lungs

The lungs in aging pets may have decreased elasticity leading to a reduction in the lung capacity. This can lead to a decreased oxygen supply to the blood and problems with breathing during anesthesia.


Recommendations to consider prior to surgery

With these potential changes in your older pet organs, there are some recommendations you should strongly consider prior to anesthesia

  • Physical exam: It is important your pet has a complete physical exam prior to any anesthetic procedure. This allows for determination of any heart problems, breathing issues, or any other medical problems that could pose a problem for anesthesia. In most cases, your pet would have had a full physical exam which determined it needs a procedure.
  • Lab work: Blood work can help determine if there are problems with organ function or existing diseases that can compromise your pet under anesthesia.
  • Additional diagnostic testing: If your pet has a history of respiratory issues such as coughing or a known heart murmur you should consider x-rays of the chest to rule out lung or heart disease. An ultrasound of the heart should also be considered for pets with a heart murmur.


What is involved in the anesthetic protocol?

Veterinarians may make adjustments for in an anesthetic protocol for your older pet to help compensate for the potential loss of organ function. Below are possible components that may be involved in maximizing the safety of your pet.

  • Placing an intravenous catheter and administering fluids: This is important to help maintain or improve circulation which can improve elimination of anesthetic drugs through the liver and kidney. As a result, the chance of a smooth recovery is greatly enhanced. An intravenous catheter will also allow quick access to a vein in case of an emergency. This is essential if drugs need to be given to help speed up the heart or stimulate breathing. Fluids can also be warmed prior to entering the body to help maintain temperature.
  • Premedication: Premedication involves giving a sedative to the pet prior to anesthesia. Sedating allows the pet to relax reducing stress. It also allows for less anesthetic needed to keep the pet under for a procedure.
  • Using drugs that allow for quick recovery: There are some anesthetic drugs that don’t require as much metabolism by the liver and kidney to be eliminated by the body. As a result the patient is likely to have a quick recovery. A popular anesthetic used in older pets is Propofol which is quickly eliminated from the body through the respiratory system.
  • Monitoring equipment: Devices to monitor heart rate, circulation, respiration, blood pressure and temperature are often used during anesthesia. These can make undesirable changes easily identifiable allowing for quick intervention.

Discuss costs vs. benefits with your veterinarian

There may be circumstances where your older pet may have a medical condition where a surgical procedure is the best treatment. But your pet may have existing health conditions such as heart or liver disease. In these cases you will need to discuss the costs or risks of surgery vs. the benefit of the treatment with your veterinarian. An example would be if a pet has an abscessed tooth that needs to be extracted. Obviously as long as the tooth remains in the mouth the pet will remain uncomfortable. So in this case it may be worth the risk to remove the tooth.


Anesthesia in your older pet does not have to be a death sentence. It is important as your pet’s advocate you ask questions about the anesthetic protocol and monitoring equipment that is available. It is also imperative you don’t decline important recommendations that can help determine your pet’s health status prior to anesthesia. Sometime that may mean an additional cost to you, but it is well worth it for your pets well-being.

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