The reason for increased anesthetic sensitivity is the low amount of body fat that Sighthounds possess, and decreased liver metabolism of some anesthetics. Sighthounds have a higher ratio of lean muscle mass to total body fat. Body fat is important in that some anesthetics, such as barbiturates, require redistribution from the blood to the body fat in order for the patient to recover from the anesthetic. With their use, some Sighthounds were unable to tolerate anesthetic procedures, and had serious complications. Luckily, today there are many anesthetics that are safe for Sighthounds.
Veterinarians are able to perform surgery and other medical procedures with safety and confidence.
In order to anesthetize a dog, a veterinarian must either inject a liquid anesthetic agent into a vein or muscle, or administer an anesthetic gas. This is the safest way to maintain and control the depth of anesthesia. Various injectable anesthetics are available. As discussed, barbiturates, which are injectable anesthetics are more risky in Sighthounds because of their body fat content and liver metabolism. In my practice, barbiturates are never used.