Analgesia in critical care.

All medical interventions, including the provision of analgesia, are associated with risks and benefits, which, when considered together, comprise that intervention's risk/benefit ratio. All interventions have alternatives (including no intervention), and each alternative possesses its own risk/benefit ratio. Clinical decision making involves comparing and contrasting the risk/benefit ratios of alternative interventions (relative risk/benefit ratio). The most formidable limitations of drug treatment relate to their potential to produce pharmacologic side effects or complications. Careful monitoring and the use of strategies for preventing and managing drug side effects are often all that is required to maintain efficacy.     

Analgesia of small mammals.

Small mammals receive analgesics much less frequently than more familiar species such as dogs and cats. This is probably related to the greater difficulty of recognizing pain in these species, and the uncertainty as to the most appropriate analgesic regimen to implement when the presence of pain is suspected. However, the same principles of pain assessment and analgesic use that are applied when dealing with other companion animals can be used to manage pain effectively in small mammals. All of the commonly used analgesic agents can be used safely and effectively in small mammals, although the size of many of these animals limits the use of techniques such as epidural administration or transdermal drug delivery systems. As with other species, it is important to integrate an analgesic regimen with the overall scheme of perioperative care, and to try to implement preemptive and multi-modal analgesic therapy.     

Analgesia and analgesic techniques.

In recent years, there has been a great increase in our understanding of pain mechanisms and our awareness of pain in small animals. Despite increased knowledge, many animals still go undertreated or untreated. Small exotic animals are a unique group of patients, and can prove challenging for the practitioner concerned with their welfare. This article reviews the process of nociception and how one can intervene in the pain pathway. Newer analgesic drugs are discussed, along with some novel administration techniques that can be adapted for small mammals. Ketamine has been regarded primarily as a chemical restraining agent, but new information reveals that it may have an important place in pain management.     

Analgesia and chemical restraint for the emergent patient.

This article discusses analgesia and chemical restraint for the emergency patient. As illness or injury affect all organ systems, specific recommendations and considerations of analgesic, anesthetic, and restraining regimens are presented. As animals of all ages, from neonates to geriatric and those that are pregnant or lactating,may require management of their illness or injury, recommendations for these patients are also presented.     

Epidural vs. Intramuscular Oxymorphone Analgesia after Thoracotomy in Dogs

Oxymorphone was administered epidurally (0.1 mg/kg) or intramuscularly (IM) (0.2 mg/kg) to 16 dogs undergoing thoracotomy, to compare the analgesic effectiveness. Heart rate, respiratory rate, systolic and diastolic blood pressure, and pain score were measured hourly. Arterial blood gases were measured at hour 1. A single dose of oxymorphone injected epidurally provided analgesia for up to 10 hours, whereas the IM route provided a comparable effect for less than 2 hours. There were statistically significant increases in heart rate, and systolic and diastolic blood pressures at hour 2 in the dogs treated IM over the dogs treated epidurally. We conclude that epidurally administered oxymorphone is highly effective in alleviating pain after thoracotomy in dogs and provides longer lasting analgesia than the IM route.     

Clinical Analgesia in Reptiles

Reptile pain and analgesia is only beginning to be understood in veterinary research and clinical medicine. The diversity of the class Reptilia also makes it difficult to extrapolate analgesic efficacy across species. Many veterinary clinicians argue that the administration of analgesic medication is risky to the patient and may mask behavioral signs of pain, which are considered evolutionarily adaptive for survival. However, veterinarians have an ethical obligation to treat painful conditions in all animals, including reptiles, because effective pain management reduces stress-induced disruption to homeostatic mechanisms and also decreases morbidity and mortality associated with trauma or surgery. Nevertheless, several obstacles limit successful analgesic use, including subjectivity of pain assessment, inadequate knowledge regarding analgesic efficacy across species, pharmacokinetics of analgesic drugs, and the unknown relationship between risks and benefits for this class of drugs. The objective of this review is to provide a current perspective on the practical application of analgesic medication in commonly maintained pet reptile species.     

Multimodal and Balanced Analgesia

Veterinary Research Communications - Corletto, F., 2007. Multimodal and balanced analgesia. Veterinary Research Communications, 31(Suppl. 1), 59–63     

Epidural Analgesia in the Dog

Fifty-four noncesarean cases in which epidural analgesia was used as the primary control of surgical pain in the dog are presented. The technique, indications, mechanisms of action, advantages, and disadvantages are discussed. Our experience with this proven technique has shown epidural analgesia to be an effective, practical, and simple means of operative pain control with wide application beyond the usual indication of cesarean section.     

Analgesia After Lateral Thoracotomy in Dogs Epidural Morphine Vs. Intercostal Bupivacaine

One of two analgesic treatments was randomly assigned to 40 dogs undergoing lateral thoracotomy. Group E (20 dogs) received an epidural injection of morphine (0.1 mg/kg) before surgery. Group I (20 dogs) received injections of bupivacaine around five intercostal nerves when the thorax was about to be closed. All dogs were given an opioid as part of their preoperative medication (meperidine or butorphanol), followed by thiopental for induction and halothane or methoxyflurane for maintenance of anesthesia. Scores were assigned for preoperative demeanor and response to restraint and injection. Alertness, undisturbed pain behavior, and response to palpation of the wound were assessed 3, 6, 12, and 24 hours after surgery. Dogs that appeared uncomfortable were given analgesics. Blood for evaluation of arterial blood gases was obtained at 3 and 6 hours after surgery. The person scoring the dogs was blinded to the treatment given. There were no statistically significant differences between the groups. Group E contained more "nervous" dogs (12 vs. 6) and more dogs in group E received postoperative analgesics (8 vs. 2). Both techniques appeared to provide adequate analgesia for most dogs.     

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.