Ketamine is a neuroleptic anesthetic. It is actually one of the safest general anesthetics in use, under normal situations. It is most often used along with valium as the induction agent prior to placing the endotracheal tube to deliver the gas anesthetic. (It is pretty much impossible -and not recommended- to place a trach tube in a normal, awake animal-- the animal must be sedated.) It is also used for short surgical procedures. (Although many vets use it alone for major procedures such as spays, this is contraindicated.)
Ketamine does not cause respiratory or cardiopulmonary depression at correc dosage level, unless it is given too fast. However, it does cause increased cardiac output, increased intracranial pressure, and is fairly long acting. For this reason ketamine should not be used in animals suffering from epilepsy, heart failure, renal or hepatic (kidney or liver) disease, or in trauma cases or for certain procedures. (Myelograms, spinal taps, etc.) Ketamine is also not safe in animals with eye injuries or who are to undergo eye procedures, as it causes increased intraocular pressures.
Probably the biggest problem with ketamine is that it has fairly long wakeup times (the iso wears off long before the ketamine does), with the animal having little motor control for somet ours, and it causes hypersensitivity to sounds and noises when the animal is waking up. Ketamine recoveries are often characterized by tremors, thrashing, etc. Although this is much more of a problem in cats. One of the biggest side effects of most interest to us pug lovers is that Ketamine exacerbates hypersalivation.
Ketamine should not be used in animals with thyroid problems whether they are on thyroid medications or not, because it can cause life threatening increases in heartrate and blood pressure in these animals. Ketamine should be used cautiously with halothane gas anesthesia as it can result in prolonged recovery times (a no-no with pugs) and cardiac depression. In our practice we use ketamine for cat restraint and for induction for routine procedures with relatively healthy animals (endoscopies, wound repairs, etc.)
We use propofol or oxymorphone (or some other protocol) on our other patients for inductions (or propofol alone for very short procedures), including our brachycephalics. We have plenty of these drugs at hand, and we prefer the shorter, smoother recovery times. Plus, most of the animals we are anesthetizing are sick animals, so we can't use ketamine anyways.
Diana Teaman CVT Certified Veterinary Technician.