tpvets_logo.jpg (2726 bytes)TOA PAYOH VETS
      Date:   12 May, 2012  
Focus: Small animals - dogs, cats, hamsters, guinea pigs & rabbits
Key Performance Indicators - Spay Surgery
Dr Sing Kong Yuen, BVMS (Glasgow), MRCVS
12 May, 2012 
Be Kind To Pets
Veterinary Education
Project 2010-0129
Follow-up on a spayed Chihuahua
Today May 9, 2012, I phoned the father and daughter of the Chihuahua 8 months, Female, I spayed as a benchmark and example to Dr Daniel on May 6, 2012. It is very useful to know the effect of pain-killers and compliance by the owners.

On May 6, 2012, Sunday, I spayed Chihuahua, Female, born June 18, 2011, said to be 10 months old. She was 1.7 kg, good bodily condition,38.7 deg C. Vulva slightly enlarged.

Bleeding heat said to be 2 months ago. Health check by Dr Daniel, . Hx:. Ab  E/D/T Well. No V+/D+/C/S. PE: BAR, active. heart/lungs normal. GIT normal (abdo palp - no pain). menses 2 months ago. Does not want blood test screening of health.

Dom and Ket Sedation at 50% and isoflurane gas maintenance and the dog woke up at the end of last stitch.

Ovaries and uterine bodies enlarged and congested as if on heat/infected (see images)/0 absorbable suture x 1

Post op tolfedine + baytril injection SC

Home medication

1. tolfedine painkillers x 3 tablets (not given at all). Now Day 3. Advised owner to give. Owner will give crushed tab in banana.

2.  trimeth x 1 bottle, multi-vit x 1 bottle. Owner had given. "Almost all medicine is taken," the father said there was no problem and so did not give the 3 tolfedine pain-killer tablets.

Post-op observations by the owner (father) is as follows:

Day 1 and Day 2 after op. Not active but can walk to pee and poop as normal. Will eat dry food if the owner added chicken wing meat

Day 3 - Not eating since chicken wing meat not added. I advised the owner to continue with chicken wing meat as an eating dog recovers faster.

Will give crushed tolfedine powder with bananas as dog like bananas

Bandage changes advised but father is afraid the stitches will come off. "No problem with the stitches as they are quite tight," I said. "Wash away the dried blood clots and replace with new bandage on Day 4 or 5.

It seems like this spay has no post-op complication despite the owner not giving the tolfedine tablets. But there was a tolfedine and baytril injection post-op.


Liquid medicine is easier to give in this case.

Crushed painkiller tolfedine tablet within meat ball may be advised. The owner said bananas can be used as the dog loves bananas. A follow-up is important after spay but vets usually don't have time to do it and 99% of the cases have no post-op problem anyway. So we don't do it.

Bandage changing may be difficult for the owner.

lst day is always the inactive day. By Day 3, the female spayed dog should be eating normally.

In this case, she was eating when chicken wing meat was added, even on Day 1.The father thought of stopping the chicken wing meat on Day 3 to prevent the Chihuahua from being picky but I advised him not to, till the dog has recovered from surgery, in around 14 days. There is no need for stitch removal in spays done by me and so I doubt I will see this dog from Rivervale in North Singapore again.

Key Performance Indicators for a veterinary surgery - spay of a Chihuahua
Case study of a Chihuahua spayed by Dr Sing K Y

Sunday May 6, 2012

New client. A young lady with her parents from North Singapore had booked me to spay their Chihuahua. Female, 8 months. Said to have heat 2 months ago. I noted that the vulva was still swollen.

I used this case to mentor Dr Daniel so that he could see how an experienced vet would handle a case in the fastest, safest and most efficient way. Veterinary surgery text on spays don't reveal the practical aspects of the real life and death situation.  He was to ask questions about the spay.

1. PRE-OP.

1.1 Inpatient record. General health check up by Dr Daniel. Weight of dog: 1.7kg

1.2 The owner did not want blood test.

1.3 Clipping the surgical area outside the Surgery Room.

1.4 Anaesthesia & surgical record. Dr Daniel to calculate sedation dosage at 50% of the formula for Domitor (0.034 ml) + Ketamine (0.043) IV and add equivalent amount of 0.07 ml normal saline to make it 0.14 ml to be given IV by me.

1.5 Absorbable suture packet 3/0 x 1 was prepared. However, I used 2/0.


2.1 Sedation by m (Dr Sing K Y).  Mr Min would hold the dog and distended the left foreleg cephalic vein. He was still not good at this despite his at least one year of experience. Somehow,  he did not press the right elbow skin area and so the cephalic vein was not distended. I tried the IV but found no blood drawn out. I asked him to twist the skin to the side and the cepahlic vein was visible.

For some reasons, Mr Min can't distend the cepahlic vein in some dogs but could do in others and today was his bad day.

I knew the dog would not stay still long. So, once I injected and saw the blood gushing inside the syringe, the dog started withdrawing her left foreleg. I injected immediately instead of waiting. There was no time to waste as the full dosage to be given was just 50% of the calculated dose. "The whole dosage might not be injected," I said to Dr Daniel as the dog had withdrawn her leg as I completed the injection. It was a wink of the eye. However, the dog quietened and dropped her head. She was sedated within 60 seconds.

2.2 As 50%* of the formula is insufficient sedation for intubation, I asked Mr Min to give isoflurane gas at 5% for less than 60 seconds. It was around 40 seconds. I intubated the dog. There was slight coughing but soon the dog was anaesthesized and maintained on isoflurane at around 1%. Mr Min was to record the % at 5-minute intervals.

(*At 100% of the formula, no isoflurane gas would be necessary but I seldom use 100% as isoflurane gas is much safer and the dog wakes up at the end of spay. Giving 100% would delay waking up. Each procedure has its pros and cons).

2.3 Dog's belly shaved and cleaned.

2.4 Skin and linea alba incision. In this dog, the umbilical scar was not distinct. So I made the incision a bit further than the usual 1 cm from the scar. I showed how I blunt dissected the subcutaneous fat in less than 2 seconds to show the white fibrous linea alba. Many new vets took longer to find the linea alba due to slow dissection and separation of the fat. Sometimes, the new vet could not see the linea alba due to the cloudiness of the SC fat masking the white line. A piece of SC fat could be cut off if the dog was fat so that the linea alba can be seen.

Then I had to extend cranially to expose the left ovary as the ovary was leaning very close to the cranial edge of the incision without giving me access to the ovarian ligament. "The left ovary is more cranial than the left," I said to Dr Daniel. "I have to extend the incision to expose the whole ovary and the ovarian ligament."  

QUESTION. "You didn't break the ovarian ligament of the left ovary," Dr Daniel said as I extended the incision of the linea alba cranially by 3 mm and could ligate the ligament.

REPLY. "There is no need to break the ovarian ligament in the Chihuahua if the left ovary is well exposed," I said. "You will note that the right ovary is easily exposed as it is more caudal and I did not need to cut or rupture the ovarian ligament. However, in larger breeds and with small incision, the ovarian ligament can be stretched and cut before ligation of the ligament."

3. The uterine body was ligated once. 
4. Linea alba closed with 3 interrupted sutures.
5. Skin incision  (2 cm long) was closed with 2 horizontal mattress sutures.
6. No bleeding but the ovaries and uterine bodies were swollen and red, indicating heat was still present. There was some bleeding of the surrounding tissues due to the dog being on heat.

7. Post-op tolfedine and baytril SC. 4 days of tolfedine. One bottle of trimethoprim and one bottle of multi-vitamin. E-collar and bandage of wound.

8. Dog woke up just as I completed the last stitch as I had asked Mr Min to switch off the isoflurane 1 minute as I stitched the skin.

SUGGESTION. "It is better not to switch off the isoflurane and disconnect in case of emergency," Dr Daniel suggested.

ANSWER. "Based on the smooth anaesthesia, such happening is unlikely. However, the endotracheal tube is still inside the dog if there is an emergency." In any emergency, there will be cardiac massage first, in my experience, rather than oxygen.

POST-OP.  The Chihuahua got up without crying within 2 minutes of completion of stitching. This meant I don't need to give Antisedan antidote to reverse Domitor. The surgery took a longer time as I had to extend the cut cranially and to hook out the left uterine horn. In this case, after 6 tries and hooking up the small intestine, I switched to hooking out the right uterine horn and was successful. This delay added up to several seconds. Normally, I could hook out the left uterine horn in 3 attempts. But veterinary surgery is full of surprises.


                  Weight             Domitor           Ketamine

Healthy, young, 10kg        0.4 ml               0.5 ml

Healthy, young, 1.7kg       0.068 ml           0.085 ml

*Give 50%                           0.034 ml           0.043 ml

Actual given  0.03 ml + 0.04 ml = 0.07 ml. Add 0.07 ml normal saline. Total IV = 0.14 ml.

A: Injection of induction drugs: 10.45 am
B: Isoflurane first given: 10.46 am. Intubated.
C: Isoflurane gas stopped: 11.15 am
D: First skin incision: 10.54am
E: Skin stitching completed: 11.17 am
E-A = 33 minutes

E-D = 23 minutes

C-B = 29 minutes


The Chihuahua spay surgery by an experienced vet with 40 years of spay experience like me took around 23 minutes in this Chihhuahua. It could be as short as 15 minutes but I don't expect younger vets to achieve this benchmark. However, one hour is too long.

TIP:  "The hydraulic operating table must be adjusted to the proper height for the vet to operate comfortably and efficiently," I said to Dr Daniel. Each vet has his or her own height and so it is best not to bend double by not making full use of the hydraulics of Toa Payoh Vets' operating table in long surgeries like spay.

QUESTION:  "How is it possible for a spayed dog to bleed on heat when she is spayed?" Dr Daniel asked me when I said that there are complaints of dogs and cats still cycling with heat when they have been spayed. "Usually there is a bit of ovarian tissue left behind," I explained that the left ovary is more cranial. So, a vet may incise a bit of ovarian tissue after ligation of the ovarian ligament. The prevention is to make a bigger linea alba incision to expose the whole ovary and ligament. This means making a big skin cut which cannot be helped. Owners are unhappy when spayed dogs and cats come on heat staining the floor with blood and with cats, continuous caterwauling can drive the owner crazy as evident in one case of a spayed cat.

A spay is not that simple after all. Besides being on heat, there are reported cases of stump pyometra. I encountered one such case of a dog spayed by Vet 1, in the last 40 years of practice and that would be due to remnant of ovarian tissues left during spays.

All veterinary surgeries will adopt a consistent process and approach as described in this case study. I will be doing my trust and audit of some veterinary surgeries done by my associate vets.

In the April 20, 2012, AVA Veterinary Clinic inspection of Toa Payoh Vets, the letter of the annual renewal of the licence mentioned that the clinic was well managed. I intend to ensure that it will be well managed with the trust and audit procedures. It will always be difficult to effect changes for the better and this needs time and explanation.    


Electro-GP-trichoepithelioma/20120342tn_guinea-pig-male-3years-large-ear-tumour-electrosurgery-toapayohvets-zoletil-isoflurane.jpg tpvets_logo.jpg (2726 bytes)5131 - 5141. Ulcerated ear tumour.
Electro-surgery to excise a guinea pig's trichoepithelioma using Zoletil 100 & isoflurane
tpvets_logo.jpg (2726 bytes)


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Be Kind To Pets
Veterinary Education
Project 2010-0129
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