General Anaesthesia

Pete Wedderburn
21st December 2020 - 2 min read

General anaesthesia for animals and humans is very similar. The equipment, drugs and principles are the same in many cases. This article explains the anaesthesia process and associated risks.

Anaesthesia process

The Anaesthesia process is a common routine in many veterinary hospitals. It follows the steps below:

Step 1: The initial knock-out injection is given to the animal which causes the animal to fall into a deep sleep for a few minutes.

Step 2: The vet inserts a rubber tube through the mouth, into the windpipe of the animal.

Step 3: The tube is tied in place and is connected by another tube to an anaesthetic machine. The machine controls the concentration of gas ensuring the animal is at the right stage of consciousness at all times..

Step 4: When the procedure is finished, the anaesthetic gas is turned off. The animal breathes pure oxygen through the tube and the tube is removed. The animal slowly regains consciousness.

Risks of Anaesthesia

There is an unavoidable risk with all general anaesthetic procedures. The same applies to humans and animals alike.

Even in the most highly skilled hospitals, there are rare cases where there are complications that occur during a routine anaesthetic. Today, the risk is minimal for healthy animals.

The introduction of electronic breathing and heart monitors has reduced the risks of complications. When an animal faces the first sign of struggle a loud high pitched alarm goes off and the team know to take corrective action. There is also an emergency kit on the anaesthetic trolley in case of emergencies, containing all of the necessary drugs. 

The improved safety of modern anaesthetics means that operations can be given to older animals nowadays. In the past, it would have been considered high risk and the animal ruled out as too old to survive a general anaesthetic. There have been many cases of dogs of seventeen years undergoing major operations without any complications!

With that being said, there still is a risk with older animals so general anaesthesia is only carried out after a series of preliminary investigations. During this investigation, the heart and lungs are checked to ensure that they are healthy. Blood tests may be carried out to ensure that the liver, kidneys and other organs are functioning normally before deciding whether it is safe to administer anaesthetics. During the anaesthetic itself, special techniques, such as carefully controlled intravenous medications, may be used on older dogs.

A busy veterinary hospital may administer ten or more general anaesthetics during a day’s work and most animals go home the same day or the following morning. Vets do not need to advise their patients to avoid driving a car for the rest of the day, but we do generally ask owners to treat them with extra gentleness!

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