Anesthesia Of Exotic Animals

摘要

Limited access to a number of patients and wide variety in species of exotic animals require special instrumentation, routes of drug administration, techniques, and pharmacology to perform a safe anesthesia. Drug application of air-activated darts with a blow pipe is the most commonly used remote delivery system in zoo work. Immobilization is mostly performed with drug combinations of opioids, cyclohexamines alpha2-adrenergic agonists, and neuroleptics. Anesthesia may be maintained by the inhalant anesthetics halothane or isoflurane administered with portable precision-calibrated vaporizers. Induction is performed with various designs and sizes of face masks, induction chambers, or endotracheal tubes. Minimal monitoring equipment includes thermometers to assess rectal body temperature and a pulse oximeter. Medical emergencies in anesthetized exotic animals mostly result from cardiovascular and respiratory dysfunction as well as special conditions like bloat, vomiting and aspiration, and various life-threatening syndromes known as capture myopathy. Introduction Veterinarians are frequently called upon to anesthetize a wide variety of mammals, birds, reptiles, and fish. In contrast to the basic principles of anesthesia in humans a lot of additional factors have to be taken into account in free-ranging or zoo animals. First of all there is a wide variety of species of exotic animals. Some of them, such as rabbits, rats, and mice, have been used through the years to assess anesthetics, and a large amount of data is available concerning anesthesia in these species. Others have been anesthetized rarely if at all, and specific information on the effects of anesthetics and methods of achieving anesthesia is minimal. Furthermore, special attention has to be directed to the different anatomy and physiology of pulmonary and cardiovascular systems in birds, reptiles, and fish.Another point is that access to dangerous or free-ranging animals and application thereto of an anesthetic is difficult, neither exact weight nor actual health status can be predetermined. Additional factors such as nutrition, disease, parasite load, infection, estrus, pregnancy, and lactation are also major anesthetic considerations, but usually cannot be assessed with certainty at a distance. In these cases, special remote drug delivery systems are necessary for anesthesia. Instrumentation and routes of drug administration In the late 1950s, the first complete remote delivery system became available (1) but the concept was not new. People of South America, Asia, and Africa have for centuries used arrows and spears with plant or animal poisons for hunting. Poison-coated darts have been used by South American Indians for hunting of birds and small mammals by the means of a blow pipe (Fig. 1). Made from wood or cane and using palm wood splinters for darts, the blow pipe is about 3 meters long and has an effective range of up to 40 meters (!) in the hands of an experienced hunter.