If you have ever broken a bone or had major surgery, chances are you will have had a general anaesthetic. Anaesthesia in any species carries uncertainties but, compared with humans — or dogs — equine anaesthesia is particularly risky not least because of the horse’s size.

Hard anaesthetic facts
There are many published studies that have attempted to quantify the risk associated with anaesthetising horses, but by far the most comprehensive investigation was the Confidential Enquiry into Perioperative Equine Fatalities, an international study that included more than 41,000 horses subjected to general anaesthesia in the late 1990s and early 2000s.

The study determined that the risk of anaesthesia-related death in healthy horses is about one in 110, increasing to one in 20 for horses anaesthetised for fracture repair and one in eight for horses anaesthetised for colic surgery.

Fatality risks?

  • 1 in 110 for healthy horses
  • 1 in 8 for horses undergoing colic surgery
  • 1 in 20 for horses having fracture repair surgery
  • 1 in 900 for cats
  • 1 in 1,800 for dogs
  • 1 in 10,000 for humans

For the full vet feature on general anaesthesia, see the current issue of Horse & Hound (12 May, 2011)