Guinea Pigs and Anaesthetic

This week I took Nutmeg, one of my guinea pigs, to the vet because of a lump she had on her tummy which had grown slightly bigger and harder recently. Unfortunately, we were told that it was most likely to be cancer. This horrified me although I was not surprised. But now I have to make some decisions. The vet whom we consulted suggested two options:

  1. Go through an operation and have it removed
  2. Wait until it gets very bad, ensuring she has a good life, and consider euthanasia when necessary

Number 1 – ADVANTAGES – removes the cancerous lump                                                   – Nutmeg can live a long and happy life                                                                               – Saffron doesn’t get lonely                                                                    – prevents the lump developing and getting worse

                – DISADVANTAGES – the RISK of surgery and anaesthetic on small animals                                                           – may take a long time to recover                                                                                    – problems with two guinea pigs after the operation                                                          – trauma


Number 2 – ADVANTAGES – likelihood of a relatively long time to live and be happy                                                         – prevents disadvantages from surgery                                                              – enjoying life to the full for Nutmeg and me

                – DISADVANTAGES   – Nutmeg will suffer when the lump becomes worse                                                           – she will have to be put down                                                                  – worry as it worsens

But to make a good judgement as to what to do, I feel that I must explore the risk of putting a guinea pig through surgery, especially because of the anaesthetic.

When reading on ‘The Guinea Pig Forum’, I found that most people who have had their guinea pigs put under general anaesthetic have come out successfully. The only deaths I read about were those not directly caused by the anaesthetic, but rather the problem the guinea pig was first suffering with. Furthermore, a big risk with anaesthetic is the heat loss involved when the animal is not moving so cannot maintain the correct core body temperature. This is enhanced by the large surface area to volume ratio of small animals such as guinea pigs causing the amount of heat lost to worsen. Therefore, a major concern with anaesthetic is the hypothermia which can result from it if the guinea pig’s temperature is not carefully monitored throughout and after the operation until it has completely recovered. Also, they should be treated by an experienced small animal vet who knows what they are doing. As well as this reactions could be caused by the anaesthetic resulting in unpredictable risks and infections could arise post-op if the wound has not been stitched sufficiently.

This table demonstrates the risk of animals dying when put under anaesthetics. Although initially it appears that there is not that high a risk for guinea pigs, being only 3.8%, when compared to humans, the 19000 times more likely of death within guinea pigs becomes evident as well as the fact that they are most at risk than any other animal displayed on the table, including hamsters and rats which are smaller but still appear under other small animal species.

However, I also learnt and found interesting, that different types of anaesthetic have different risks involved, some being safer than others. These I read to be Isoflurane and Sevoflurane, which are generally used and considered to be safe. Also, both are inhalation agents.


  • can contribute to hypothermia in small animals through causing vasodilation (the dilation of blood vessels, which decreases blood pressure)
  • can be irritant to the tracheal mucosa, sometimes causing animals to breath-hold even when heavily sedated (normally only a problem in rabbits)
  • provides good skeletal muscle relaxation with only mild to moderate cardiovascular and respiratory depression

  • rapid recovery


  • rapid recovery
  • potential respiratory problems in guinea pigs

In conclusion, I believe that I could safely choose to put Nutmeg under anaesthetic in order to remove the cancerous lump, however, as she is a happy piggy who does not seem to suffer nor even notice that the lump is there, I will probably not choose to go with surgery. The research I have done in order to make this decision has been very interesting and I feel that I am now satisfied in the knowledge I have gained about the processes of putting guinea pigs under anaesthetic.