Services: Anaesthesia

If you would like to learn a little more about what we do behind the scenes, and what is involved when your animal comes in for surgery then please browse this section.

Anaesthesia can be divided into the following phases:

• Pre Anaesthesia
• Induction phase
• Maintenance Phase
• Recovery Phase

Pre Anaesthesia

Your pet is given a sedative and pain relief (analgesia) 15 - 20 minutes prior to anaesthesia in order to minimise the amount of anaesthetic your pet needs during her surgery.

Induction phase

This is where we give an intravenous anaesthetic drug, which rapidly makes the patient unconscious. It allows us to be able to pass a tube into the airway to deliver the anaesthetic gases, which will keep the patient anaesthetised during the procedure.

The induction agent is given into the vein "to effect", that is; the correct dose for the body weight of the animal is calculated but then only the amount that is necessary for each individual patient is given.

A tube (endotracheal tube) of the appropriate size is then passed into the animal's trachea. In cats, the larynx is first sprayed with local anaesthetic, as cats are prone to spasm of the larynx. This is not a problem for dogs.

The endotracheal tube is then tied into place with string up and over the animal's nose. The tube has a soft, inflatable cuff on it to create a snug fit in the trachea. This is inflated with a small amount (1-2ml) of air.

Maintenance Phase

The patient is then attached to the gas anaesthetic system. This system provides oxygen and anaesthetic gas to the patient to keep them anaesthetised at the correct depth for the procedure. All anaesthetised animals are kept warm by a thermostatically controlled heating mat. They are positioned on the anaesthetic table on a moulded cradle. They have ointment placed in their eyes to stop the corneas becoming dry.

Monitoring anaesthetic is a complex task. It is best achieved by constant monitoring by a qualified veterinary nurse or vet, with assistance from specialised anaesthetic monitoring equipment. Every animal has an anaesthetic record filled out.

During the procedure, the patient is monitored to keep them at the right depth of anaesthetic - that is, if too lightly anaesthetised then the patient might have some reflex movements when surgery is being performed and if too deep then the heart or breathing rates may decrease.

Some variables are measured manually by an oesophageal stethoscope (a tube placed into the oesophagus to rest near to the heart and connected to the earpieces of a stethoscope) and checked against those values measured by the machines..

Recovery Phase

Once the procedure is nearing completion, the anaesthetic gas level will be slowly decreased, over about 5 minutes, to allow the animal to gradually regain consciousness.

The animal will be given extra pain relief, to help facilitate a smooth recovery. Once the gas is turned off, the animals are left to breath 100% oxygen for about 5 minutes, then they are allowed to breath regular room air again. Once they show signs of regaining awareness then the endotracheal tube is removed and the animal is placed into a recovery cage. This is lined with a padded blanket and they are kept warm.

Most animals regain consciousness within 10 minutes of stopping the anaesthetic, can sit up within about 1 hour and are able to walk within 2 or 3 hours. This varies a lot depending on the procedure and the time spent under anaesthetic. They normally rest in hospital until they are bright enough to be discharged.