Anaesthesia

Anaesthesia is used for a variety of veterinary procedures, including surgical, diagnostic and dental procedures. Anaesthesia will ensure your horse is kept pain-free during these procedures.

Anaesthesia is defined as a loss of sensation. Anaesthesia will stop your horse from feeling pain and other sensations, and it can be given in various ways. It is used for a variety of veterinary procedures, including surgical, diagnostic and dental procedures.
There are different types of anaesthesia including:

  • local anaesthesia
  • regional anaesthesia
  • sedation
  • general anaesthesia

This numbs a small area of your horses body, e.g. to repair small superficial skin wounds or to perform a skin biopsy. Your horse will remain conscious during a local anaesthetic.
Local anaesthesia can be topical (used to numb the surface of the body) using a gel, cream or eye drops, or given by injection to numb slightly deeper tissues.

Regional anaesthesia, also known as nerve or joint blocks, is used for procedures on larger/deeper parts of your horses body, e.g. for lameness investigation. Your horse will remain conscious during regional anaesthesia.
Nerve blocks are given by injection, whereby anaesthetic medication is injected near a cluster of nerves to numb a specific area of your horses body.
Joint blocks are given by injection, whereby anaesthetic medication is injected into a joint, tendon sheath or bursa to numb that specific area.

Small amounts of anaesthetic medication are used to induce a sleepy-like state, e.g. to enable the safe use of diagnostic imaging such as x-rays and ultrasound. When sedated, your horse will be physically and mentally relaxed.
Sedation is given by injection and can be given at differing levels depending on the situation:

  • Light sedation for example may be used when clipping an awkward horse, or used on a horse that is getting distressed when on box rest or on restricted turnout.
  • Medium sedation for example may be used when undertaking diagnostic procedures such as x-rays or ultrasound.
  • Heavy sedation for example may be used when suturing minor wounds or for castration.

General anaesthesia (GA) is used to cause total loss of consciousness when more complicated procedures/surgery is required, e.g. repairing broken bones or colic surgery.
GA involves injecting anaesthetic medication intravenously (into a vein) via a catheter. When under general anaesthesia your horse will not be aware of its surroundings and will rely on the veterinarians and nurses involved to continuously assess the airway, heart rate, nervous system and reflexes.
GA in horses is more complex than in many other species, therefore your horse will undergo a pre-anaesthetic evaluation to ensure he is in good health.

Pre-anaesthetic evaluation

Your vet will give your horse a physical examination, including examination of the heart and lungs and checking for signs of existing infection or disease; blood tests may be recommended to help identify any medical conditions. Anaesthesia may be postponed or cancelled if any health problems are discovered.
Your horse will then be weighed to ensure the correct anaesthetic doses are given.
GA is usually given in a padded box which reduces the risk of injury as your horse lies down. Initially your horse will be heavily sedated and an intravenous catheter will be placed which allows safe access to the vein for the duration of the procedure. A breathing tube will also be inserted into the windpipe for the administration of gases and oxygen which will keep your horse anaesthetised. Sometimes, instead of using gases, injectable anaesthetic medication is used through an intravenous drip, this medication is continued until the patient is permitted to wake up.

Anaesthesia, as with any surgical procedure, has its risks. Some horses can have adverse reactions to the anaesthetic or experience an irregular heart rate, problems breathing or abnormal blood pressure while under anaesthetic.
Your vets will be highly trained in performing anaesthesia on horses, and will take every possible precaution to ensure your horse wakes up safely.
If you have any concerns or questions, make sure you speak to your vet before your horse is due to undergo any procedure involving an anaesthetic.