VMD 513: Pet animal Breeding, Management, Nutrition and Health Care (1+1)

GENERAL ANESTHETICS

• General anesthetics are used when an animal needs to be unconscious and unaware of what is being done for an extended period of time, such as for surgery. General anesthetics block the pain sensation, prevent movement during surgery, and usually cause muscle relaxation.
• Thiopental is an ultrashort-acting barbiturate, which is used for induction of general anesthesia or for very short procedures, such as suturing a small wound or removing porcupine quills. It is injected directly into the vein and unconsciousness occurs within a minute. Greyhounds and other sight hounds may have a longer recovery period than other breeds. This may be due to their low body fat levels or differences in how the body breaks down the anesthetic.
• Ketamine and Telazol are other injectable anesthetics used for restraint or short procedures, such as draining an abscess. Telazol is used in cats and dogs. Ketamine is used in cats; it provides no muscle relaxation. Ketamine and Telazol function differently than most other injectable anesthetics. They produce 'dissociative' anesthesia, which means the animal is not aware of what is going on. The animal's eyes remain open and reflexes are generally present.
• When using a general gas anesthetic, the animal is given an induction agent such as thiopental to bring him to unconsciousness. Then the gas anesthetic is mixed with oxygen in the anesthesia machine and is administered via a face mask or an endotracheal tube placed in the pet's trachea (windpipe). Commonly used general gas anesthetics include, isoflurane and halothane. They are both rapidly taken up and eliminated from the body by the lungs. Isoflurane has become the anesthetic of choice in veterinary medicine, and its use is especially indicated for pregnant animals (including c-sections) and for animals with heart problems.