Saturday, July 24, 2010

141. Spaying A Chow Chow

Chow Chows are an uncommon breed in Singapore. They have a compact narrow abdominal area and a broad chest unlike Miniature Schnauzers or cats. So, it is hard to hook out the ovary using the method I am describing below. I record one case of a spay in a Chow Chow to share knowledge with veterinary students.

Patient: Chow Chow, female, 10 months old, 18kg. 39.7C (due to car ride and excitement, vomiting inside the car. Don't spay till 4 hours later)

Last Estrus: 3 months ago. This means that there will be less bleeding when the dog is spayed 3 months after the heat.

Anaesthesia: Domitor 0.25 ml IV although 0.3 ml should be OK too. Then isoflurane gas mask and intubate. IV saline drip given.
"Emergency drugs are to be given inside the IV drip," I explained to Ms Lai, the young intern who wants to study to be a vet. "But the best way is to prevent emergencies from happening by having one assistant monitoring the breathing bag, checking the eyelid reflexes and gum and tongue colour every few seconds. Equipment like ECG, pressure measurement, breathing sound measurement and others are useful but nothing can be beat a competent focused assistant."

Ms Lai already has a degree but she intends to be a vet and is doing a 2-month internship at Toa Payoh Vets. She seems passionate about veterinary medicine and so I explained much about the behaviour and medical and surgical problems to her the new world of dogs and cats, rabbits and hamsters and other small animals to her.

"Old man James used to be my assistant," I said to Ms Lai. "But now he is 75 years old and so he can only observe the breathing bag. When the dog under anaesthesia stops breathing, the bag will stop moving. If the assistant only observes the bag and nothing else, it may not be sufficient or too late. He has to observe the mucous membrane colour and check the eyelid reflexes as well as observing the rotation of the eyeball downwards to confirm surgical anaesthesia."

I don't know how much Ms Lai understands my explanation as she is so new to this world of veterinary anaesthesia and this is the first spay she is watching. My competent assistant Mr Saw was focused on anaesthesia.

"In the case of the Chow Chow, there is no point checking her tongue," I said to Ms Lai. "Look at her tongue. It is naturally purplish black and so we can't see the red colour of oxygenated tongue. We have to check the eyelids."

There was no problem with anaesthesia. Mr Saw tends to put on the lowest dosage to sometimes as low as 0.5%. "It is best not to put to such low rates," I said to Mr Saw. "The omental fat keeps popping out making it very difficult to stitch the muscles to close the wound. 2% gas will be sufficient for this Chow Chow. When I go to the skin incision, you can switch off the gas as Domitor is still sedating."

Overall, this Chow Chow had a very smooth anaesthesia. I took out the endotracheal tube as I saw her reacting by moving her mouth. She woke up with a head turned sideways for a few seconds. This was normal as she was under Domitor sedation. An Antisedan antidote would wake her up completely but we had to clean up the wound and apply the plaster.

Surgery:
1. Body fully stretched out.
"Stretch out the dog as much as possible," I said to my assistant and intern. "I use a 2-cm incision and insert the spay hook to the right and 45 degrees downwards to hook up the ovary. From my experience, it is much easier to hook out the left ovary. Otherwise, the vet may take a very long time to hook out the ovary. I have seen one new vet graduate actually sweating when he spay a big fat mongrel as he could not hook out the ovary for over 10 minutes. If it is difficult to hook out from a small incision, just extend the incision and it will be much easier."

My assistant could not stretch out the left hind leg as there was some jam in the operating table's sliding ring. "I will use my hand to pull the left hind leg," the intern proposed. Well, she had ideas as she could not manage to resolve the jam. My assistant did it.

N.B. Some vets incise around 4 cm from the umbilical hernia scar. In this position, the ovaries are harder to assess and the taut ovarian ligament may not be assessed and cut so easily as in my method. The vet has to pull the ovarian ligament to cut or rupture it using fingers. There is a danger of bits of the ovarian tissue retained during this difficult manipulation. However, each vet has his own ideas and experiences.

2. Skin incision:
Approximately 1.5 to 2 cm from the umbilical scar.

3. Linea alba incision:
Remove the subcutaneous fat. Look for the linea alba. The Chow Chow's body is compact and this 1.5 - 2 cm incision is too small to see the linea alba clearly. But it can be seen. Incise the linea alba. Subcutaneous fat can be seen below this small hole.

4. Spay hook:
With one forcep holding one edge of the muscle, I inserted the spay hook at 45 degrees to the right (dog's head to the vet's left), tilted the hook downwards and had to arc the hook upwards and to the left to hook out the abdominal fat with the ovary. In this Chow Chow, there was much omental fat. I failed the first two times to hook out the ovary as the fat was in the way. At the 3rd time, I saw a glistening knob at one end of the omental fat hooked out. This was the ovary. I used the forceps to clamp a bit of the ovarian tissue and after that, it was simple.

5. Bleeding after separation of omental fat from the uterine horns:
As I separated the omental fat around the uterine horns, prior to clamping the uterine body, there was a gush of bleeding. I clamped the uterine body lower to the bleeding area. The bleeding stopped. I ligate the uterine horns in two locations. No bleeding. Put the uterine stump inside the body.

6. Loosen the tautness of the body:
I asked my assistant to loosen the tight ropes around the dog's paws so that the body is now relaxed. The rest of the spay is as described elsewhere in my website.

7. 2/0 absorbable suture. 2 simple interrupted stitches closed the peritoneum and the muscles. I gave an additional 1 more stitch. Skin is closed with 2 horizontal mattress.

8. Bleeding in the skin sutures. I asked the intern to press swab onto the bleeding area. Bleeding stopped after 10 minutes.

9. Elastoplast bandage covered the wound. The dog could be bathed. No e-collar as I doubt that this Chow Chow likes e-collars. In any case, tolfedine painkillers post-op injection and oral for next 4 days would prevent pain and licking.

10. The dog was able to wag her tail and walk when the owners came one hour after the operation to take the dog home. No Anti-sedan antidote was given as the dog could stand up and walk. The mother was relieved as she was worried about anaesthesia but did not express this worry to me earlier. I could sense it as deaths on the operating table due to anaesthesia are are common worry for many owners.

Spaying this Chow Chow at 3 months after the last heat was the correct timing made by the knowledgeable lady owner. There was practically no bleeding from the omental or ovarian fat and surgery could be completed earlier. Still it took some 30 minutes to do the surgery and I don't look forward to do more spays in Chows Chows owing to the greater difficulty of hooking up the ovaries.

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