Answer: Almost all the surgical operations on cats are performed under general anaesthesia. (General anaesthesia implies a generalized loss of sensation accompanied by unconsciousness.) The use of general anaesthetic is most important for humane reasons; it prevents fear and pain during the operation, and by avoiding pain, greatly minimizes surgical shock which would otherwise frequently prove fatal. In addition, general anaesthesia relaxes the muscles and avoids the possibility of movement, which is an important pre-requisite for successful surgery, particularly on delicate or complex structures.
Because of the use of general anaesthesia, the normal reflex movements are temporarily abolished, including the coughing reflex. Normally any material which attempts to enter the larynx at the back of throat provokes a violent about of coughing to prevent its passing down any further, i.e. down the trachea.
Under general anaesthesia vomiting can occur if there is food or water in the stomach, and this material will pass up to the back of the throat, where the digestive and respiratory tracts cross each other. Because of the lack of an effective coughing reflex, there is then a grave risk that some of the material may pass through the larynx and down the windpipe to the lungs. Such vomited material, containing acid from the stomach, is very irritant and would provoke a severe pneumonia, which is invariably fatal.
Furthermore the pressure of the stomach distended with food on the abdominal side of the diaphragm can interfere with normal breathing whilst the cat anaesthetized.
It is avoid these potentially serious consequence that food and water must be restricted prior to general anaesthesia. Because food can be retained in the stomach for several hours, an over night fast is usually advised, which means that an animals is not fed after its normal evening meal on the day before it is to be anaesthetized.
Water is removed from the stomach much more rapidly and it is therefore usually sufficient to prevent drinking on the actual day of anaesthesia. In all cases follow your veterinary surgeon’s advice. Longer periods of the deprivation are undesirable because they weaken the cat and reduce his chance of successfully withstanding the stress of surgery.
There are two other important points:
1 Don’t feel sorry for the cat and give it drink against your veterinary surgeon’s instructions, because you may literally kill it with kindness.
2 Tell the vet, or his nurse or receptionist, when food or drink was last consumed. If you know, or suspect, that the animal has in fact eaten or drunk after it was supposed to do, say so, don’t conceal the fact. It is usually better to postpone the operation then to expose the animal to an unnecessary risk.
