Saturday, July 16, 2011

505. A 2.5-hour perineal hernia repair surgery and anaesthesia

Sunday July 17, 2011

Four days ago, I did a 2.5-hour perineal hernia repair in a 10-year-old Silkie Terrier with no heart disease. I share my experience while the details are still fresh in my mind.

1. The owners have been reminded many times that they may not see the dog alive as the anaesthetic risks in an old dog are extremely high. As the dog has no heart disease, the chances of survival are 40%. Usually, the owners will sign a Consent Form.

Details of benefits, risks and complications should be recorded in the case notes, just in case of litigation but few vets do it. In a recent human medical case, from what I read in the newspapers, the specialist was suspended by the 3 judges for failing to write down the risks and complications in his case notes. Therefore, he could not defend himself. He did my colonoscopy well and that is why I remember his litigation case well.

A complete blood test was done. Only abnormal finding were low urea and creatinine.

The dog was active, trim and fit in appearance. The heart and lungs were OK on routine examination.

I waited 3 days to perform the hernia repair surgery so that the owners and the family members have time to think about the high-risk surgery. Sometimes the owners may want to go to another vet surgeon or a brand-name practice and that will be OK with me. This surgery is the type "where fools go in where angels fear to tread" as the hernias are bilateral and incredibly massive. Clinical outcomes may not be what the owners expect. The dog may die on the operating table since it will be a long anaesthesia and the perineal hernia may recur later.

Sedation (domitor + ketamine IV) is required as there is a need to knock the dog out smoothly during maintenance (isoflurane gas) anaesthesia. This is to prevent the intestines and bladder from coming out during surgery and the dog pooping (atropine 0.5 ml IM given). Isoflurane gas alone without sedation is possible but is not so effective as the dog struggles during the initial stage and may be stressed out.

IV anaesthesia and topping up is NOT advised although it can be done. This is because the surgery takes a long time as there are two hernias.

I use the following formula as a guideline.
For a young healthy dog of 10kg bodyweight and one year old, Domitor is 0.4 ml mixed with Ketamine 0.5 ml in one syringe. This formula gives good analgesia without the need for isoflurane gas maintenance for a half-hour spay.

This case:
Old dog -10 years old, 6.5 kg bodyweight
Domitor 0.15 ml + ketamine 0.2 ml in one syringe IV
This dosage was very low but permitted the dog to be given 5% isoflurane by mask with a little struggling. Intubated and given 2-2.5% isoflurane gas maintenance. "Don't reduce to 1%," I said to my assistant Mr Min. "Even if the dog's anaesthesia is deeper as the intestines, bladder and omental fat will bulge out suddenly, disrupting my surgery."

Atropine 0.5 ml IM was given prior to mask with isoflurane. Sometimes, stool pellets keep coming out during surgery. In this case, no anal straining. The anal opening was plugged with gauze.

Isoflurane anaesthesia at 2 - 2.5% maintenance was excellent over the 2.5-hour surgery.

1. I gave 5% glucose at around 50 ml. The tongue looks redder when the dog is given glucose IV. The dog was starved from 10 pm yesterday.
2. Normal saline IV drip is given after the glucose IV.

1. The left hernia was very large and repaired first. Large intestinal coils with inflamed serosa were just under the skin. So, the vet has to be very careful.

2. The right hernia was in two holes separated by a muscular septum. Omental fat seen.

3. On first electro-incision of the thin skin which was lifted up to incise, a large quantity of light brown fluid shot out. This would be the exudate but looked so much like urine. Be careful as the bladder was also present.

4. I suture the ventral area first. Then mid or top layer. Suture from muscle to the wall of the anal sphincter. Interrupted and continuous sutures. I used 2/0 absorbable sutures in the lower layers. The topmost layer was closed with 1 Maxon absorbable monofilament.

5. According to the text books, the pudendal nerves and blood vessels are at the lower 1/3 of the hernia. In theory, this is excellent. In practice, the whole area is swollen, bloody and messy. The hole is so deep and wide.

It was not possible to identify and avoid the nerves and blood vessels in this case where the hernia was very long-standing. In fresh small perineal hernias, the nerves and blood vessels can be seen as according to the text books!

The dog was deep in anaesthesia even 20 minutes after the end of anaesthesia. I gave 0.25 ml Antisedan IM. He woke up within 5 minutes. It is important that the dog wakes up as he is an old dog. But sometimes, it is best for the dog to wake up gradually and I don't given Antisedan reversal.

I gave baytril and tolfedine SC. Then follow up with oral. I find that tolfedine is not very effective based on recommended dosage of once per 24 hours. Twice a day for the first 2 days may give pain relief.

My assistant did not give an e-collar. So, the dog licked the left side of the wound to relieve his pain as tolfedine in recommended dose was ineffective. My assistant changed to a much larger e-collar as the dog continued licking.

Two days of post-op bleeding. Nursing is important.

The dog ate canned food for the first two days. Water given freely. Passed loose stools. So far, so good as at Saturday (Day 4). Today is Sunday 6.30 am
and I will see him later.

This is the type of challenging and high risk surgery that I hope not to see as nowadays, the clients are more litigious and the vet just have to be careful and selective of customers. Not all customers are good for the vet unlike the marketing theories where all customers are welcome.

When the clinical outcome is not good, many family members who are not at the consultation start becoming abusive in some cases. This is the brave new world. Where hard-earned reputation built over the years can be destroyed by some family members who make lots of unjustified complaints of negligence and costs. The majority of my clients are happy ones fortunately for me.

Many more pictures illustrating the problems met are shown in:

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