Local and regional anesthesia.

Local anesthetics have the unique ability to produce complete blockade of sensory nerve fibers and prevent or pre-empt the development of secondary (central) sensitization to pain. For this reason, local and regional anesthetic techniques are often used with opioids, alpha 2-receptor agonists, dissociatives, and anti-inflammatory drugs as part of a multimodal strategy to manage pain. Lidocaine and bupivacaine are the local anesthetics used most commonly in dogs and cats. Lidocaine has a fast onset (10-15 min) and an intermediate duration of action (60-120 min), and is used for short diagnostic and surgical procedures. Bupivacaine has a slow onset (20-30 min) and a long duration of action (240-360 min), and is used to control pain both preoperatively and postoperatively. Local anesthetics are relatively safe if they are administered correctly. Administration of an excessive dose and accidental intravenous administration are probably the most common causes of systemic toxicity in small animals. Doses of local anesthetics, especially those for cats and small dogs, should always be calculated carefully. In many animals, the most simple and elegant way to control pain perioperatively is to perform a local or regional anesthetic block. Veterinarians should not hesitate to incorporate local and regional anesthetic techniques into their pain management strategies for dogs and cats.     

Protocols for anesthesia of cattle.

The article explores the choices and considerations pertinent to the selection of an anesthetic protocol for use in cattle. When the veterinarian is presented with the opportunity to provide anesthesia for surgical or diagnostic procedures, the options include use of local anesthetics, sedative-tranquilizer and analgesic combinations, or general anesthetic techniques. Informed decisions regarding selection of an anesthetic technique or protocol are made possible with understanding of the perianesthetic considerations commonly recognized for cattle.     

Local and regional veterinary history

Continuing a review, written in 1992, an overview is given of the five recent studies on local themes. The author emphasizes that telling a story of local traditions and usages, of striking personalities or personal experiences can illuminate the problems of a broader national or even international context. He points to the fact that the local archives contain many materials of veterinary historical relevance waiting for exploitation.     

Intravenous regional anesthesia (Bier block) in a dog.

Intravenous regional anesthesia was used in an adult dog as part of a balanced approach to general anesthesia for amputation of the 4th digit of its right hind limb. It allowed the concentration of isoflurane to be reduced to 0.5%.     

Practical tips for modified dorsolumbar epidural anesthesia in cattle

Segmental dorsolumbar epidural anesthesia has been considered difficult to perform. The purpose of this study was to determine whether or not it is difficult for beginners to learn how to do modified dorsolumbar epidural anesthesia of cattle. Thirty cattle were divided into two groups, young (n = 8) and adult (n = 22), according to their age and body weight, and 0.12% new methylene blue (NMB) was injected into the first interlumbar (L1-L2) epidural space by four fifth-year veterinary school students who had never performed this method. After a 1 hour lecture on the modified dorsolumbar epidural anesthesia procedure which included basic anatomy and skills, each student successfully performed the procedure. In the young group, the NMB solution was distributed between the periosteum and the epidural fat (BPF) in one half and between the epidural fat and the dura mater (BFD) in the other half of the cattle. In about 60% (13/22) of the adult group, the NMB solution distributed as BFD type. This study showed that the modified dorsolumbar epidural anesthesia procedure is easy for beginners to perform if they overcome their fear about the deeper insertion of the epidural needle with basic anatomical knowledge and a little experience.     

Pain management and regional anesthesia for the dental patient

Current standards of care in veterinary medicine dictate an adequate level of pain control for our patients. Effective pain control uses a proactive, multimode approach that starts with preoperative medications, includes the anesthetic protocol selected, and continues into the postoperative period. A basic understanding of the physiology of pain assists in selecting those agents and modalities best suited for individual patients. Analgesic drug selection and local anesthesia are both integral parts of pain control when performing surgery in the oral cavity. Local (regional) anesthesia plays an important part in the pain control of oral surgical patients. Regional anesthetic techniques are used for many common oral procedures, including extractions, periodontal flap surgery, treatment of traumatic injuries of the oral cavity, tumor removal, palatal surgery, periodontal therapy, and root canal therapy. This presentation will cover strategies for analgesia and the techniques and materials used in local/regional anesthesia in the oral cavity. Anatomic landmarks and guidelines for effective regional blocks will be covered.     

The most important local anesthesia in cattle: a review

Surgical interventions in cattle are frequently performed under local analgesia. Local analgesia may be carried out in the standing animal without or with slight sedation or with the animal in recumbency after deep sedation. Injection of local analgesics is less time consuming than induction and maintenance of general analgesia and is, therefore, frequently used in private veterinary practice. Precise anatomical knowledge of the nerve supply to the area to be operated is a prerequisite for the successful introduction of a local analgesia. The goal of the present review is to summarize nerve supply and indications for surgery in the area of the head, male genital tract, teat and the claws of the hind limb of cattle.     

Retrospective evaluation of xylazine/halothane anesthesia in 125 cattle

A retrospective morbidity and mortality study was carried out on 125 case records of cattle involving xylazine/halothane anesthesia at the Ontario Veterinary College, Guelph between May 1979 and February 1983.     

A review of ophthalmic local and regional anesthesia in dogs and cats

Objective

Orbital and globe surgeries are commonly performed in companion animals and are considered to cause moderate to severe pain. Regional anesthesia techniques can provide complete sensory blockade, analgesia for painful procedures and improve surgical conditions. The purpose of this review is to summarize local and regional anesthesia techniques for ophthalmic surgery in dogs and cats with emphasis on veterinary publications in the past 12 years.

Local anaesthetics for regional and intra-articular analgesia in the horse

During the course of a lameness examination, intra-articular or perineural administration of a local anaesthetic is often necessary to isolate the source of pain causing lameness. Local anaesthetics are useful for intraoperative and post-operative pain relief and may allow for elimination of, or a decrease in, general anaesthesia. Within recent years, new information has become available concerning the use of local anaesthetics for localisation of pain and for palliation of pain. New information indicates that

• Lidocaine is less efficacious than mepivacaine or ropivacaine in ameliorating lameness caused by pain.
• After administering a nerve block, loss of skin sensation may not correlate with loss of pain causing lameness.
• Local anaesthetic solution must be deposited within the sheath of the neurovascular bundle to be effective.
• The dose of a local anaesthetic, which is a factor of volume and concentration, affects potency and duration of a nerve block.
• Local anaesthetics are toxic to chondrocytes and synoviocytes. Lidocaine and bupivacaine appear to be more toxic than mepivacaine or ropivacaine. The clinical significance of the toxic effect of a single intra-articular injection of local anaesthetic is yet to be determined.
• Sodium bicarbonate can be added to a local anaesthetic solution to increase its potency and speed of onset.
• Epinephrine added to local anaesthetic solution prolongs and intensifies its analgesic effect.
• Mixing quick-acting, short-duration and slow-acting, long-duration local anaesthetics will not result in a quick-acting, long-duration drug combination.

     

Relationships between prevalence of Leptospira interrogans in cattle, and regional, climatic, and seasonal factors.

On the basis of serologic test results and isolation of leptospires from mature cattle, distribution and prevalence of Leptospira interrogans serovars and genotypes were compared by state and region of the United States. Relationships between isolation rate and month of sample collection, mean regional temperature, and mean regional precipitation were examined. Isolation rate and seroprevalence were significantly (P less than 0.001) higher for southeastern, south central, and Pacific coastal regions than for other regions of the United States. Isolates of genotypes hardjo-bovis A and kennewicki A and B, and of serovar grippotyphosa appeared to be randomly distributed. Genotype hardjo-bovis B isolates came from a southern area of the country that extends from Georgia to New Mexico. To the authors' knowledge, this is the first recorded isolation of serovar hardjo from Hawaii. Although significant relationship was not documented between isolation rate and month or season of the year, seroprevalence for summer, fall, and winter was significantly (P less than 0.001) higher than that for spring. Regional isolation rate was related more to mean temperature (r = 0.83; P less than 0.05) than to mean precipitation amount (r = 0.34; P greater than 0.50).     

Ceftiofur distribution in plasma and joint fluid following regional limb injection in cattle

The objective of this study was to evaluate the efficacy of regional intravenous (i.v.) injection of ceftiofur in delivery of this drug to joint fluid and plasma in a limb distal to a tourniquet in five, healthy, adult, mixed breed beef cattle. A tourniquet was positioned in the mid-metacarpal region, and 500 mg of ceftiofur was administered through a catheter in the dorsal common digital vein (DCDV). Plasma samples were collected from the catheter at 15, 30 and 45 min postinjection, and from the abaxial proper palmar vein (APPV) at 15 min postinjection. Synovial fluid was collected from the metacarpal phalangeal joint at 45 min postinjection. Ceftiofur concentrations were estimated in plasma and synovial fluid using high-pressure liquid chromatography (HPLC) and a microbiological assay utilizing Pasteurella haemolytica as the test organism. Both assays indicated highest plasma concentrations of ceftiofur at 15 min, with the concentrations declining with time. Concentrations of ceftiofur in plasma obtained from the DCDV were not significantly different from APPV levels, indicating rapid distribution of ceftiofur within the limb. Microbiological assay always demonstrated higher concentrations of ceftiofur compared with HPLC assay, because the former probably also detected the active metabolites of ceftiofur as well as the parent compound. At 45 min, ceftiofur concentrations determined by HPLC were 251+/-97 and 15+/-5 microg/mL in plasma and synovial fluid, respectively. Regional intravenous injection appears to be a feasible technique to produce rapid distribution of ceftiofur within the limb well above therapeutic concentrations.