Specialist Referral Service

Willows Information Sheets

General anaesthesia

© WILLOWS VETERINARY CENTRE AND REFERRAL SERVICE

Willows Information Sheets www.willows.uk.netT: 0121 712 7070

General anaesthesia

Why does my pet need to be anaesthetised?

Many of the procedures we need to carry out cannot be performed on a conscious or sedated

patient because they will not be relaxed enough. Unlike humans, we cannot ask our patients to

place themselves in specific positions required for X-rays, scanning or surgery. Although we can use

local anaesthetics to numb a surgical site, administering the local anaesthetic in itself may cause

discomfort and it does not prevent animals from moving during the surgical procedure.

What is an anaesthetic?

There are several types of anaesthesia, but all of them lead to a loss of sensation. General anaesthesia is

a state of reversible unconsciousness when your pet will be ‘asleep’ under the anaesthetic. Anaesthetic

drugs injected into veins or anaesthetic gases breathed into the lungs are carried in the bloodstream to

the brain. These drugs stop the brain recognising messages from nerves in the body. This is different from

the unconsciousness than occurs in injury or disease.

What do I need to do to prepare my pet for surgery?

• You will need to fast (starve) your pet overnight – your pet

should have their normal meal the night before admission

(unless otherwise instructed), but should have no further

access to food after this. However, he or she should have

free access to water until you leave the house to come to

the surgery.

• Cats should be kept in during the night before the procedure

to prevent them helping themselves to food from elsewhere

and to make it easy to find them in the morning!

• Take your dog for a walk in the morning to allow him or her

to empty the bladder and bowels.

• Watch out for any signs of illness not related to the

procedure which is about to be carried out on your pet, and

let the vet or nurse know if you have any concerns.

• Have a note of your pet’s current medication, including over-

the-counter preparations, and make sure that the vet or nurse

knows about these at the time of admission.

What happens after my pet has been admitted?

The anaesthetic drugs to be used will be chosen according to the

procedure that is being performed and the medical history and

findings on physical examination of your pet. Your pet will then be

injected with pre-anaesthetic medication (a ‘pre-med’).

After an appropriate amount of time, an intravenous catheter will

be placed, to allow administration of drugs and fluids during the

procedure. For most pets we will then use this catheter to inject

an intravenous anaesthetic agent which allows us to place a tube

(called an endotracheal tube) down the patient’s wind pipe (trachea).

During most of the procedure, further anaesthetic drugs are

administered as a gas through this endotracheal tube.

How do you keep my pet safe during general anaesthesia?

Our aim is to provide the best care for your pet at all times,

including during general anaesthesia. To this end, Willows is

fortunate to have a team of dedicated anaesthetists, including two

recognised, accredited anaesthesia Specialists, who are on hand to

supervise and assist with each anaesthetic procedure, as required.

For the whole duration of general anaesthesia, your pet will be connected

to an anaesthetic machine, which delivers a mixture of anaesthetic gas

and oxygen. The amount of gases and the type of anaesthetic circuit used

is adjusted to the needs of each individual patient.

While your pet is anaesthetised, he or she will be closely observed

throughout the procedure by veterinary anaesthesia staff and/or

highly trained, qualified nursing dedicated to the one-to-one care

of your pet. In addition, specialised monitoring equipment is used

to keep a close watch on your pet’s progress. The monitoring

equipment used depends on the surgical procedure, type of

anaesthesia used, and medical history of each patient.

At Willows, we use monitoring equipment which measures:

• heart rate and rhythm (electrocardiography or ECG)

• pulse rate

• respiratory rate

• body temperature

• blood pressure

• oxygenation of blood (called pulse oximetry)

• carbon dioxide level in the breath (called capnography).

The staff involved will also monitor your pet’s pulses, gum (mucous

membrane) colour, position of the eye and reflex activity to determine

the depth of anaesthesia. All the readings obtained and any observations

are recorded every 5 minutes on an anaesthetic record chart.

When the surgical procedure is complicated or for a pet with a

higher risk of undergoing anaesthesia, more information about the

patient is required to make sure that he or she remains safe and

comfortable. To obtain this information we use more advanced

monitoring techniques, including:

• ‘invasive’ arterial blood pressure measurement (using a

cannula which is placed in an artery to directly measure

the arterial blood pressure, rather than using a cuff)

• central venous pressure monitoring (measuring the blood

pressure in the veins deep inside the body)

• measuring the level of muscle relaxation (called

neuromuscular blockade)

• measuring of breath (spirometry)

All this information is important, and it helps us to anticipate

potentially significant problems almost before they occur. If there

are any concerns, an anaesthetist can take the necessary actions to

bring all the parameters back to the normal levels as promptly as

possible. The adjustments required under such circumstances may

include giving additional injections, more pain relief, supplementary

intravenous fluids or oxygen. If there is any problem with the

breathing, your pet will be connected to a unit which automatically

inflates the chest (mechanical ventilation) to make sure enough

oxygen is provided.

We will take special care to make sure your pet is warm during

whole procedure and on recovery. Under general anaesthesia, the

brain does not control body temperature and patients can lose heat

very quickly. It is especially important to maintain body temperature

in small, young and short-haired animals. We use a range of

© WILLOWS VETERINARY CENTRE AND REFERRAL SERVICE

Willows Information Sheets www.willows.uk.netT: 0121 712 7070

warming devices to prevent heat loss – in the operating theatre our

patients are placed on special heated beds with in-built sensors, and

intravenous fluids are heated by fluid warmers.

When a procedure has finished, the anaesthetic gas is switched off

and the patient is given oxygen until he or she starts to recover and

wake up. Most pets recover consciousness very quickly, although

older animals or those who have had a longer anaesthetic may

recover more slowly.

During recovery, your pet will be taken to a warm and comfortable

bed in the kennels (or our Intensive Care Unit if required) and will be

carefully monitored until he or she is fully awake.

How is my pet prevented from feeling pain?

Most of our patients undergoing anaesthesia will receive at least

two types of painkillers. The most commonly used are the morphine

type drugs and drugs from the aspirin family (the so called ‘non-

steroidal anti-inflammatory drugs’ or NSAIDs). We also use different

techniques and medications, taking into consideration your pet’s

history and the procedure he or she is having.

For more information about pain and its management, see our

information sheet ‘Pain – an overview’.

What will my pet be like after coming home from Willows?

If your pet is discharged on the day of surgery, he/she will probably

be a little sleepy. Strong painkillers will have been given and these

will last some time. You should offer your pet some light food (e.g.

boiled chicken or fish and rice) and water, but do not expect him

or her to have a normal appetite. The effects of the anaesthetic will

wear off over the next few days. Please look out for any signs of pain

or discomfort and contact the practice if you are at all concerned.

What can I do for my pet after a general anaesthetic?

• Provide him/her with a bed in a quiet, warm area.

• Do not let cats go out until the next day, if at all possible, as

their balance may not be back to normal.

• Take your dog out to the garden or for a very short walk to

allow him/her to pass urine, but do not let him/her off

the lead.

• Follow the instructions provided by your vet for medication

and general care which is specific to his/her condition.

Why should I bring my pet to Willows for a procedure under general anaesthesia?

Our anaesthesia and analgesia department is led by highly

experienced recognised, accredited Specialists who aim to provide

the safest possible sedation, anaesthesia and pain management

for your pet. Our anaesthesia/analgesia team works alongside the

other Specialists at Willows who are highly trained in a wide variety

of different disciplines. They oversee all the general anaesthetic

procedures which are carried out at Willows, in addition to

supervising sedation and pain management regimes tailored to each

patient’s needs. They liaise closely with our 24-hour veterinary and

nursing staff, all of whom help not only to give our patients the best

possible outcome, but also to ensure that they remain comfortable

at all times, whatever their problems may be.

If you have any concerns at any stage after your pet’s operation,

please do not hesitate to contact us.

© WILLOWS VETERINARY CENTRE AND REFERRAL SERVICE

Willows Information Sheets www.willows.uk.netT: 0121 712 7070

Specialist Referral Service

www.willows.uk.net

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or utilised in any manner in whole or in part, without the express prior

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