How do you remove the big tumour without killing the guinea pig? This was Chinese New Year's Eve and the mum had starved the pet overnight in preparation for the surgery.

What mum wanted was a live guinea pig at the end of surgery. 

Injectable Zoletil IM sedated the guinea pig. He was still feeling active. I gave him isoflurane gas anaesthesia at 5% for <10 seconds. It is important that minimal gas is given. A gas mask fitting the snout of the guinea pig brought into the gas. There was slight salivation drooling from his mouth as he breathed in the gas.

I did not use  atropine to prevent salivation as this might affect the guinea pig after surgery.

"Check his eyelids," I taught my assistant who was holding the mask how to elicit the eyelid blinking reflex. The guinea pig blinked when I touched his eyelids, meaning that he was not under surgical anaesthesia yet.

It is difficult to give just sufficient anaesthetic gas without killing the patient. I was using 5% isoflurane gas and a bit overdose would kill him. I would check his blinking reflex and took off the gas mask as soon as the reflexes were gone.

His skin lump was really big. More than 1 cm in diameter. I inserted a needle to aspirate but no pus came out. So, it would be a tumour.  There was a small bluish bruise as the guinea pig's tumour rubbed against the floor of his cage.

"He walks with a limp and with his right leg held up high," the son said. So he had surfed the internet to find out more about the problem and which veterinarian to consult.

Mum said, "Last week, there was no lump in this leg."  Therefore, this could be a malignant tumour if it has increased to such a large size in one week. 

"The guinea pig is old," I replied. "This large lump is likely a tumour - a soft fatty tumour." The mother and son left the Surgery while I admitted the guinea pig. It would be better for them not to hang around as they would be stressed. Whether the guinea pig would survive or not on the operating table depends on so many factors. Death on the operating table was not a good thing on Chinese New Year's Eve. Every relative at the Family Reunion Dinner later would get to know about the death and know which vet did it.  

There was no delay for this surgery as the tumour might double in size over one week. Under the lightest gas anaesthesia, I cut the skin and shell out the fat tumour.  5 skin stitches of 5/0 absorbable sutures closed the skin wound after removal of the big fatty tumour.  An antibiotic and dextrose saline SC given as the patient staggered to stand up.

Within 5 minutes he was looking around for food. He had been starved overnight. "Give him some pellets," I asked my assistant. This was a finicky eater but he ate one pellet. I phoned the mum and son to bring him home. They were already on the way to the Surgery. The mum's face lit up as she saw that the guinea pig greeted her and was walking normally, with four legs on the ground.

She had bought a new bag of guinea pig food from a pet shop.  "It is best that the guinea pig eats the same type of food before the surgery," I advised. "Any changes in feed may cause stress and diarrhoea." 

The family reunion dinner must be a happy one for the mum who was the caregiver for this guinea pig. The guinea pig might or might not bite off the stitches. Mum would need to use a piece of facial cotton with clean water and wipe off the blood or dirt twice a day. It is of course, not practical to get the guinea pig to wear an Elizabeth collar to prevent biting. Overall, I would expect him not to bite the stitches off as the majority of his incised skin was not infected as his tumour was only slightly bruised. 

A large tumour requires more anaesthesia and increases the risk of the pet dying on the operating table. A big incision means that the pet can lick off the stitches and create a bigger problem of a big hole that is hard to stitch and heal.

Therefore, monitor your old pet daily. If he is not walking normally, find out why.

Get tumours removed when they are small. Be Kind to older Guinea Pigs - Spot their tumours early when they are small and get them removed by your vet promptly. Longer anaesthesia and old age increase the risk of the guinea pig dying on the operating table. Deaths on the operating table can be prevented if the owner takes the time to groom and check his animal companion every day and get the small tumour removed.