Yesterday, Oct 19, 2011, I operated on this 12-year-old
again. She was a happy dog as he wagged her short tail,
unlike some dogs that had to be dragged into the vet
surgery.
The
pterygia had re-grown and covered the whole eye. Despite
anti-glaucoma eye drops given by the medically
knowledgeable owner, the glaucoma could not be cured.
Now the pterygia had covered the whole cornea as well,
nearly 100%.
"I thought you spoke to the human eye expert regarding
opening a hole in the sclera to drain the high eye
pressure?" I asked her the day before yesterday when the
dog was admitted. She had made a special appointment to
see me at 10 am as she wanted me to do her dog's
operation to take out the eyeball.
"In human glaucoma surgery," she said, "a stent has to
be inserted into the eye to drain off the excess fluid."
"The dog will not tolerate a stent inside her eye," I
said. So she gave the usual anti-glaucoma eye drops and
they worked apparently. Till the pterygia over-grew the
cornea by 100%. Eyeball enucleation was the only
alternative.
Now the surgery is relatively easy but the main issue is
that the vet must produce a dog alive at the end of
surgery. Death on the operating table is not an option.
I was much apprehensive about doing anaesthesia on this
old dog, much beloved by the family members.
I had operated on a 16-year-old with several large
circum-anal tumours. Just as I completed removal of the
tumours, the dog's tongue turned snow white. There was
no hope as there must be a rupture of the blood vessel
in the inside, probably the liver as the total whiteness
of the tongue meant massive bleeding usually.
This dog had liver disease as evident by the blood test.
I wanted to postpone the operation to a Thursday, having
put the dog on antibiotics for at least a week. However,
the owners had to take leave and so I operated on a
Monday as scheduled earlier. As to whether delaying by 3
days would make a difference to survival, it is not
possible to forecast. Anaesthesia in old dogs are high
risk and I don't take such cases unless the owners and
family members are well aware of the tremendous risks
involved. No vet cannot be 100% successful in
anaesthesia of old dogs. Deaths on the operating table
are extremely emotional and so I prefer not to operate
but some cases just can't live a good quality of life
without surgery.
As part of coaching of my assistant Mr Min, I will
record what had been done for the benefit of vet
students. In vet school, the anaesthetic theories are
sound and if you adopt them to the letter, you are
supposed to be successful.
In practice, the health and age of the old dog make
veterinary anaesthesia highly risky as this will be the
case in human anaesthesia. This is what I did for this
old dog.
Oct 18, 2011. The dog was admitted. The owner said the
dog ate well and was normal.
A DAY BEFORE OPERATION.
1. Blood test was taken.
2. No X-ray was done to reduce costs but X-ray of the
chest and ECG are done in the Singapore General Hospital
when I was operated on.
3. I gave an IV dextrose saline 500 ml + duphalyte 50 ml
to this dog. IV baytril given.
OPERATION DAY
1. Blood test was normal for this dog. This was good
news.
2. Pre-op examination. The pulse quality was poor and
the pulse was barely palpable. This was bad news. Other
than that the temperature and respiration were normal.
3. Sedation. This is how I coached Mr Min on the dosage
of Zoletil as I asked him to learn by writing on a piece
of paper the dosage calculations.
The calculation is as follows:
In the dog, the maximum Zoletil 100 is 10 mg/kg. The dog
weighed 24.5 kg and would need 245 mg. Therefore the
volume of Zoletil 100 (100mg/ml) should be 245/100 =
2.45 ml.
However, I was using Zoletil 50. In theory, I should
give 4.90 ml IV as Zoletil 50 is half the strength of
Zoletil 100. Mr Min said he understood.
I took out a 1-ml syringe and gave the dog Zoletil 50 at
0.5 ml IV. This is 10% of the calculated dose. The
12-year-old dog was unable to stand 2 minutes after the
injection. For a young dog, the dosage would be
ineffective.
4. Isoflurane gas by mask 10 minutes later. 5% given
initially.
"Check the left eyelid blinking reflex," I told Min as
he was looking at the chest movements. "When the eye
white (sclera) is seen, that means the dog is in
surgical anaesthesia. That means the eyeball has rolled
downwards. This is such a simple method of assessing the
onset of surgical anaesthesia but many vet assistants
don't use this method but rely on chest movements. "When
chest movements stop," I said to Min, "It is already
very serious heart failure. Put your finger onto the
eyelids and see whether they blink."
It takes a lot of patience to repeat instructions to new
people. Life is like that. Some know it faster than
others. In human general hospitals you have the
specialist anaesthetist to focus on anaesthesia but for
vets in most practices, the sole responsibility is the
vet surgeon.
5. Intubation. When the blink reflex was gone, I
intubated this dog. However, she had problem taking the
isoflurane gas by tube. Her chest movements were rapid
and irregularly fast. I took out the tube, put on mask
again. There was some froth seen in the endotracheal
tube.
6. Atropine 0.5 ml IM and Lasix 1 vial 2 ml IV were
given.
7. I intubated again. The dog reacted as if the tube was
irritating. It gave vomiting sounds, as if one is
clearing the throat. No vomitus. Yet the dog appeared to
want to vomit. So I took out the tube and gave gas by
mask.
The dog struggled to get up. "Give mask at 3%
isoflurane, not 5%," I said to Min who was to be focused
on anaesthesia. "It will take a long time at 3% but it
is safer than 5%."
8. SURGERY
The dog kept curling his tongue upwards at one stage,
during mask anaesthesia. Finally he was down to be
operated. I cut 2 cm at the lateral canthus, cut the
conjunctiva circumference of the sclera. The eyeball
collapsed but was taken out. I did not pull out the
globe hard as this would traumatise the optic nerve and
affect the eyesight of the normal left eye. The optic
nerve could not be ligated. It was cut. Bleeding was
profuse. Bleeding controlled by 5 swabs after cutting
the eyeball and taking it out.
9. SURGERY DURATION
Nearly 1.5 hours due to the reactions of the old dog in
being anaesthesized by intubation. He had some
respiratory secretions and at one time, he panted or
hyperventilated for over a few minutes. There are dogs
that can't be anaesthesized using intubation which is
the favoured ideal method of giving gas anaesthesia as
they reacted to having a tube in their trachea. Why, I
don't know. It happens in very rare cases. Changing to
mask resolves the problem as in this case.
By mask, it was smooth and uneventful. The dog woke up
immediately after the last stitch.
10. POST-OP. Tolfedine 2.5 ml IM and SC (2 parts).
Baytril tablets 3 days. Then clavulox for another 10
days. Tolfedine tablets 5 days as painkillers.
11. GOES HOME IN THE EVENING. The dog was awake within 5
minutes after end of anaesthesia. E-collar. The eyeball
was swollen but no bleeding. I had put in 2 layers. 2/0
absorbable PDS to stitch up the conjunctiva (cut edges
after excising the eyeball circumferentially. Then I
stitch up the eyelid (excised 3 mm margin leaving 0.5 mm
of medial canthus eyelid uncut). Pictures shown. What
the owner wanted was a dog alive and her trust that I
could deliver. It was a happy ending.
CARRYING A BIG DOG
I persisted in teaching Min how to carry the big dog
without bending his back. I taught Nicole the
21-year-old girl who wanted to study vet medicine the
same technique. Girls must carry big dogs too if they
want to be a vet and equality and respect in this
veterinary world!
UPDATE ON OCT 30, 2011
11 DAYS AFTER SURGERY AND ON DAY OF SURGERY FOR
COMPARISON
3 IMAGES FROM THE OWNER ON 11TH DAY AFTER SURGERY
Dear Dr Sing,
Q..., the
12-year-old dog, is doing well. She is eating
and running around. Has no problems passing
motion and easing herself. Enclosed are the
pictures you asked for. I suppose her stitches
come out on the 2nd of Nov (14 days).
Thanks alot
regards
Name
Day 1
Day 11 post-operation. No
infection. No maggots. Well
cared for by the owner.
TOA
PAYOH VETS
