In most cases a preanesthetic injection is given to sedate the patient, then the gas is administered with a mask over the dog's muzzle. Once the dog is sleeping an endotracheal tube is placed in the windpipe in order to establish a direct route for the anesthetic to be delivered. Many patients control their own level of anesthesia. When they are not deep enough, they will breath harder, inhaling more anesthetic and go back to sleep. If they are too deep the respiration will decrease and breath less gas.
Safety is the veterinarian's most important concern.
Prior to anesthetic delivery the K-9 is examined, with particular attention to heart and lung sounds. In older patients diagnostic testing of organ function is often performed first to confirm the patient can safely be anesthetized. The veterinarian should be made aware of any preexisting medical conditions or medication your dog is taking. The patient under anesthesia is constantly monitored. Observing the color of the gums and the number of respiration's per minute are helpful.