Clinical Anesthesia and Analgesia in Invertebrates

Invertebrates are an expansive and diverse group of animals that have had little attention regarding anesthesia and analgesia. Economic use, environmental awareness, laboratory research, and increasing demand for invertebrates as pets has lead to a greater desire for knowledge for these animals in the veterinary medical community. With the increasing number of animal welfare regulations, various scientific studies have improved the overall knowledge of invertebrate medicine, but much more research is required to fully understand anesthesia techniques in the different species treated by veterinarians. Analgesia is a controversial and often neglected topic with invertebrates because of the common belief that invertebrates do not feel pain. Recently, the idea that invertebrates do not feel pain has been challenged with the discovery of nociceptive pathways similar to those in vertebrates. This article presents a general overview of anesthetics and analgesics used in selective invertebrate taxa.     

Clinical Anesthesia and Analgesia in Fish

Fish have become a popular experimental model and companion animal, and are also farmed and caught for food. Thus, surgical and invasive procedures in this animal group are common, and this review will focus on the anesthesia and analgesia of fish. A variety of anesthetic agents are commonly applied to fish via immersion. Correct dosing can result in effective anesthesia for acute procedures as well as loss of consciousness for surgical interventions. Dose and anesthetic agent vary between species of fish and are further confounded by a variety of physiological parameters (e.g., body weight, physiological stress) as well as environmental conditions (e.g., water temperature). Combination anesthesia, where 2 anesthetic agents are used, has been effective for fish but is not routinely used because of a lack of experimental validation. Analgesia is a relatively underexplored issue in regards to fish medicine. However, recent studies have investigated opioid agents, nonsteroidal antiinflammatory drugs, and local anesthetics to determine their efficacy in minimizing pain and discomfort. The opioid morphine and the local anesthetic lidocaine do have significant effectiveness in reducing pain-related responses in rainbow trout (Oncorhynchus mykiss). Studies aimed at developing reliable analgesic protocols should explore a wide range of analgesic drug classes in several fish species.     

Anesthesia and Analgesia in Rabbits and Rodents

Rabbits and rodents are popular pets and are often presented to veterinarians for evaluation and medical treatment. Anesthesia in exotic pets is required for many diagnostic and surgical procedures and is associated with a higher perioperative risk in rabbits and rodents when compared with dogs and cats. Inhalation anesthetic agents are commonly used as the sole source of anesthesia in small rodents, whereas injectable agents in combination with inhalation anesthesia are often used for rabbits and larger rodents. Analgesia is an important component of exotic pet medicine. Although it may be difficult to recognize signs of pain in companion exotic mammals, adequate pain management should always be provided. Opioid and nonsteroidal antiinflammatory drugs are the analgesic medications of choice, but others should be considered (e.g., local anesthetic agents). This article provides an update of the current literature regarding anesthesia and analgesia in rabbits and rodents.     

Comparison of Computed Tomographic Images of Birds Obtained With Sedation vs General Anesthesia

Computed tomography (CT) is an increasingly available and valuable imaging modality for the diagnosis of companion avian pets. Previously, CT studies of birds required general anesthesia with inhalant anesthetics. Owing to the risks associated with general anesthesia, the authors of this article investigated the effect of sedation on birds during a CT examination. In this study, 10 psittacine birds were imaged using a 40-slice helical CT scanner. Birds were sedated with midazolam and butorphanol and placed in a positioning device. Following the initial study, birds were removed from the device and placed under general anesthesia with isoflurane. A second study was then performed. Two radiologists, blinded to the identity of the birds and partially blinded to the conditions of the study, reviewed the images. Studies were evaluated using a questionnaire consisting of 18 questions. Each question was scored on a Likert scale. A Wilcoxon signed rank test compared scores of sedated and anesthetized birds. A significant difference (P = 0.05) between sedated and anesthetized studies was found for 2 of 18 (11.1%) questions for radiologist 1 and 1 of 18 (5.5%) questions for radiologist 2, with differences identified in the scleral ossicles and the femoral heads. Interrater agreement for all questions using a linearly weighted κ was 0.334 and 0.311 for sedated and anesthetized birds, respectively, indicating fair agreement. The interrater agreement, excluding the head and musculoskeletal system, was 0.381 for sedated animals, indicating fair agreement, and 0.404 for anesthetized birds, indicating moderate agreement. Based on our results, performing CT studies in birds with sedation is a viable alternative to studies performed under general anesthesia.     

家禽瘦素(Leptin)信息传导及其生理功能(续完)

续2009年第4期：上一期总体介绍了瘦素的一般情况,并详细介绍了瘦素受体的结构和基因表达。