Vet’s advice: getting an old dog spayed
“I need to have my old girl spayed and confess (having had a bad experience many years ago) to being slightly apprehensive about this. What are the risks involved?” GORDON DUFF GORDON, PERTHSHIRE
Vet’s advice Neil McIntosh SG’s gundog health expert
My first general anaesthetic on a dog was carried out on 3 August 1984 and involved me, a geriatric yellow labrador who was suffering from a womb problem called pyometra (possibly the same problem affecting yours), a 20ml syringe with needle attached and some intravenous 5% thiopentone. Note please, ladies and gentlemen, the absence of an endotracheal tube to establish a safe airway, any form of anaesthetic machine or oxygen, and not a nurse in sight. There followed a difficult two hours, during which time the anaesthetic was ‘topped up’ by way of me injecting more thiopentone with the help of a sterile swab placed over the syringe. The dear old dog survived, though slept soundly for a good day and a half before she rose unsteadily to her feet, drank a bowl of water and staggered outside to my great joy.
Fast forward 36 years and such a patient would be carefully starved for a few hours prior to surgery and appropriate sedatives, pain relief and intravenous fluids would be employed. Induction of anaesthesia would be with short-acting propofol or alfaxalone, with the help of a registered veterinary nurse who would also hold the animal’s head to facilitate careful endotracheal intubation. The patient would then be connected to an anaesthetic circuit, delivering 100% oxygen with varying amounts of gaseous anaesthetic, before monitors were connected, allowing continual assessment of heart and respiratory rates.
“I like to think of these risks as if we were crossing a road”
Mortality rate
Little wonder that, in 1990, Clarke and Hall reported an overall anaesthetic mortality rate of 0.24% for dogs and 0.29% for cats. This sub-divided into 0.12% and 0.18% for healthy dogs and cats and 3.13% and 3.33% for sick animals. Your outlook should definitely improve when you learn that, in 2006, Dr David Brodbelt of the Royal Veterinary College, in a detailed Confidential Enquiry into Peri-operative Small Animal
Fatalities (CEPSAF), determined that current mortality rates have reduced to 0.17% for dogs and 0.24% for cats, with ‘healthy’ figures being 0.05% and 0.11% and ‘sick’ being 1.33% and 1.4% respectively, so anaesthesia is definitely safer than before. However, these statistics have to be considered in the context that the mortality rate in human patients is around 0.001%.
Recovery period
A most important issue to arise from CEPSAF was that more than half of the anaestheticrelated deaths in both dogs and cats occurred during the recovery period, after the anaesthetic had been turned off, and
that many patients were unattended at this time. Clearly, when considering the risk of anaesthesia, the quality and number of staff available, and their post-operative protocol, are extremely important factors.
Surgical risk
We all worry about anaesthetics but we also have to take into account the risks involved with the particular type of surgery that is to be undertaken. Thus operating on the brain is more dangerous than removing a small lump from the skin. Your elderly patient is at greater risk than a young bitch undergoing ‘routine’ neutering. This is because the womb will be larger in size and will have a greater blood supply; there may also be issues associated with previous breeding, endometritis, and so on. I like to think of these risks as if we were crossing a road. A simple procedure is like traversing a quiet country lane. It is pretty safe but you still need to be alert. Negotiating a motorway, however, requires you to look, listen and keep looking and listening. A competent surgeon knows this and should put your mind at rest. I do hope she does well.