Anesthesia in guinea pigs

Anesthesia is a subject that often worries many owners, but at some point or another, many guinea pigs will undergo an anesthetic during their life. Therefore, it’s important to have an understanding of the subject.

Anesthesia is defined as ‘insensitivity to pain, especially as artificially induced by the administration of gases or the injection of drugs before surgical operations’.

A general anesthetic is when the patient is placed into a state of unconsciousness. They are not able to feel pain, are paralyzed and have no memory of what happens to them when they are under general anesthesia. This is achieved by interrupting the passage of signals along the nerves. This means any stimulation to the body doesn’t get processes or recognized by the brain. However, an anesthetic doesn’t have to involve a general anesthetic. Other types of anesthetics exist, such as local anesthetics which ‘numb’ a specific area, but the patient is still fully conscious.

Surgical procedures, such as neutering, dentals and anything that is likely to be painful to a guinea pig, requires anesthesia. Sometimes it may be necessary to place the guinea pig under general anesthetic for procedures when they must stay still, such as CT or MRI scanning, some x-rays, and blood samples if the guinea pig is very flighty or fidgety.

Local anesthesia

This includes injections, sprays or creams. These are normally used to block the sensation of pain along the nerve pathways, and can be used very successfully.

EMLA cream is often used on guinea pigs when placing intravenous catheters or taking blood samples and is a local anesthetic in the form of a cream that numbs the surface of the skin, meaning the guinea pig is less likely to move at the crucial moment when the needle punctures through the skin. This type of anesthesia is not suitable for surgical procedures, since the guinea pig is still able to move and feel sensation.

Epidurals create a nerve block, which means the patient remains conscious, but they can’t feel any sensation at the site of the epidural. This can therefore allow fur surgery in a conscious guinea pig.

General anesthesia

A general anesthesia places the guinea pig into an unconscious state where they’re unable to move or feel pain. This is the state that animals must be under when surgical procedures are performed on them.

There are many drugs and combinations of drugs that can be given to guinea pigs to achieve anesthesia. The choice of anesthetic is based on many factors, including the age of the guinea pig, it’s health status, and the procedure to be undertaken. All of these factors are considered when deciding which anesthetic to sue.

Normally a premedicant is given first; this helps to relax the muscles and has a calming effect on the guinea pig, but it doesn’t always render them unconscious. Often, they may need other drugs or anesthetic gas to achieve general anesthesia. Rabbits are maintained under anesthesia by delivering an anesthetic gas via a facemask which keeps them asleep as they breathe in the gas and oxygen.

No anesthetic is 100% safe 100% of the time, and no two animals ever react the same to an anesthetic, but guinea pig anesthesia has become far more reliable and safer over the last decade, although it still carries a higher risk than cat, dog or rabbit anesthesia.

Ways that risks of anesthesia are minimized include:

• Constant monitoring by trained staff when the guinea pig is under anesthetic.
• Getting an accurate weight of the guinea pig being anesthetized.
• Ensuring the guinea pig is eating and drinking properly prior to anesthesia.
• Minimizing stress, particularly placing them away from ‘predators’ in the hospital environment.
• Keeping them warm before, during and after surgery.
• Giving them medication for pain, and to help keep the gastrointestinal tract moving.
• Placing an intravenous catheter.
• Using familiar drugs that the veterinarian is confident using.

Lowering the risk however doesn’t remove it completely, and there’s always the risk the guinea pig may suffer an adverse reaction to the drugs, die under anesthesia, bleed excessively during or after surgery, or suffer complications.

Your veterinarian must point out the risks involved in an anesthetic, and for the specific procedure your guinea pig is undergoing. Your veterinarian should also be confident with anesthetizing guinea pigs and with the protocol that the practice has in place.

No!

Guinea pigs must never be starved. Unlike dogs, cats and people, guinea pigs can’t vomit due to a very strong cardiac sphincter (the muscle at the top of the stomach). If dogs, cats or people are anesthetized and haven’t been starved, then vomiting is a serious concern; if this occurs then inhaling and choking is a potential danger. As guinea pigs can’t vomit, the risk doesn’t affect them. Guinea pigs also need a constant throughput of food through their digestive system otherwise this can slow down which can prove fatal.

It’s very important to never starve your guinea pig prior to an anesthetic, and if possible, take in some of their usual food when they go to the veterinary practice for anesthetic.

Anesthesia will slow down the guinea pig’s gastrointestinal tract and reduce their body temperature. It’s vitally important to get the guinea pig eating, drinking and passing droppings and urine within 12 h, but preferably sooner. Guinea pigs in pain will be reluctant to eat and therefore if anything painful has been done the guinea pig must have pain relief and medication to try to ensure the digestive system doesn’t slow down or stop completely.