Surgery in Horses and General Anaesthetics
Putting your horse through a general anaesthetic isn’t a subject that we like to think about- that is until we have to make an important decision. We strongly believe that it is much easier and better to know the facts so that if you are ever faced with the potential of a general anaesthetic for your horse you can make an informed decision.
When is a General Anaesthetic required?
General Anaesthesia (GA) may be required during both elective and emergency surgery however, from a veterinary point of view, the protocol will always generally stay the same. GA’s are ideally performed in a hospital where your horse can be closely monitored in a sterile and safe environment.
What happens before surgery in horses?
Before GA the horse’s vital clinical signs will be taken and recorded. Some of these would be heart rate, respiratory rate, mucus membrane colour, temperature and weight. For an elective GA the horse will not have been allowed food for a minimum of 12 hours – similar to anaesthetics in humans.
A square of hair will be clipped over the jugular vein which will be thoroughly cleaned before an intravenous catheter is placed. The horse at this point is usually given its first pre-medication, specifically a mild sedative, an anti-inflammatory and frequently antibiotics, which will then allow the induction agents to work more effectively when the horse is anaesthetised.
The horse’s feet are taped with grey tape, and their mouths thoroughly washed out. (The horse’s shoes will have been removed prior to coming in for surgery). The horse is then left in a quiet environment for 20-30 minutes while final preparations for surgery are made. After 20 – 30 minutes the horse is led to a knock down box. This is a padded room adjacent to the theatre. More drugs are given which will sedate the horse even further before the induction agent is given.
The anaesthetist will usually administer these drugs, at LLEP most horses have a controlled induction using a padded swing door for restraint whilst they lie down.
The horse will then be intubated which involves passing a rigid tube through the horse’s mouth into its trachea. This allows the horse’s airway to be kept open and anaesthetic gases to be passed.
Moving the horse onto the operating table
When the horse is fully anaesthetised hobbles will be attached to the horses’ feet which allows the horse to be winched onto the table in the operating room.
Once on the operating table the horse continues to be closely monitored and recorded while anaesthetic gas is administered through a breathing system. Intravenous fluids will be given through the catheter already placed in the jugular and blood pressure monitored through a separate intraarterial catheter.
Most general anaesthetics will go very smoothly, however each animal is different, constant vigilance is needed to assess the plane of anaesthesia the horse is in. If the horse is not given enough anaesthetic it will move during surgery as it will feel the procedure, but if too much is given the horses higher brain functions will cease to work, i.e. it will stop breathing by itself.
What happens after surgery in horses?
Once the surgeon has finished the horse is winched back into the padded recovery box where they are monitored closely until they are nearly ready to come round. At this point the tracheal tube is removed as the horse is capable of breathing by itself – and a swift exit is made!
The doors are locked and the horse left quietly in the dark to hopefully recover peacefully. This usually takes between 30 minutes to an hour and a half but during this time everything is kept as quiet as possible.
At Loch Leven Equine Practice we use a rope assisted recovery procedure which involves attaching a rope to a special made head collar, and one to their dock. The ropes are then used with pulleys to assist the horse whilst they are still slightly uncertain on their feet. This substantially reduces the risks of stumbling during recovery.
A general anaesthetic is a major procedure for your horse, and owners should expect their horse to be profoundly sedated. Many hospitals will strongly advise that you do not visit your horse for 24 hours following surgery as this can be upsetting for both horse and owner. Each case is different and the aftercare and the amount of time the horse must stay in the hospital will obviously vary depending on the procedure that was performed.
The aftercare required at home will also vary but it is vital that you stick to the advice given as cutting corners can be very serious and may even prove fatal.
The aftercare following surgery is extremely important and your vets will discuss this with you in detail. It is important that the horse stays at the clinic until they are ready to go home which reduces the risk of post-surgery complications.
If you would like any additional information please call us on 01577 841010.
