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Local Anesthesia in Cats
-Sulove Koirala
Blocks the pain pathways leading to the brain from a specific area of body.
Topical Anesthesia
Lidocaine spray (10%, 100mg/ml) or Lidocaine Hydrochloride Local anesthetics, either as lidocaine spray (10%, 100 mg/mL) or lidocaine hydrochloride solution, can be applied topically. One spray delivers 10 mg of lidocaine, which usually is sufficient to desensitize small areas of oral, nasal, and pharyngeal mucous membranes. Administration of 20 mg of lidocaine to the mucous membrane produces surface anesthesia up to 2 mm deep within 2 min, which lasts for about 15 min. Topical lidocaine (spray or instillation) is useful for minor diagnostic, therapeutic, and surgical procedures (e.g., endoscopy, placement of nasal catheters for tube feeding, foreign-body removal, biopsies, and repair of small mucosal wounds).
Infiltration Anesthesia
Local infiltration is primarily used for repair of superficial lacerations, cutaneous biopsy, and removal of dermal or subcutaneous tumors. Lidocaine hydrochloride (2 to 5 mg/kg), ropivacaine, or bupivacaine hydrochloride ( mg/kg) is injected in the form of a subcutaneous bleb, line block, inverted V- block or triangular or rectangular pattern around a small tumor to be surgically removed. -> Lidocaine Hydrochloride (2-5mg/kg), -> Ropivacaine or bupivacaine hydrochloride (3mg/kg)
General Anesthesia in Cats
Induction
General anesthesia may be induced by the use of inhalational agents or, more commonly, by the use of injectable drugs.
Thiopental: Barbiturate, less commonly used nowadays because of its irritating property and development of newer and safer drugs. Dose: 10mg/ kg/IV
Alfaxalone (‘ Alfaxan ’ , Vetoquinol): Alfaxan causes less cardiopulmonary depression than other IV induction agents such as thiopental or propofol. It is very rapidly metabolized by the liver, and repeated ‘top - ups’ or constant rate infusions can be used to maintain anesthesia without significantly prolonging recovery time. Dose: 2-5 mg/kg IV
Ketamine: The main advantage of ketamine in small animal anesthesia is that it can be given by either IV or IM routes, and so, is particularly useful for fractious patients, especially cats, where it may be impossible to achieve IV access. As a highly lipid - soluble drug, ketamine provides rapid onset of anesthesia when administered intravenously. **Dose: 5-10 mg/kg ketamine
Maintenance
In current veterinary practice, maintenance of general anesthesia is most commonly accomplished by inhalational agents. However, there has been growing interest in the use of total intravenous anesthesia (TIVA) in both humans and animals over the past few years, and this field is likely to develop further in the future.
Halothane : As newer agents such as isoflurane and sevoflurane have begun to compete with halothane, its production has been significantly curtailed.
Isoflurane : The low blood solubility of isoflurane indicates that uptake and elimination will be faster with this agent compared to halothane – promoting faster induction and recovery – and that the depth of anesthesia will be easier to alter.
Sevoflurane is non-irritant to respiratory tract than Isoflurane so it is much more suitable
Nitrous Oxide is weak anesthetic so given in high concentration.
Triple combination anesthesia
The so - called ‘ triple combination ’ (more colloquially referred to as ‘ triple combo ’ ) is widely used for provision of anesthesia in small animal practice, particularly for cats. It comprises ketamine, medetomidine (or dexmedetomi- dine) and (usually) butorphanol, all mixed together in the same syringe and administered subcutaneously or intramuscularly (although it can also be used intravenously). The main reason this technique is so popular is that it will provide a reasonable period of surgical anesthesia (up to about 45 minutes depending on the dose of ketamine used), without the need for restraint for intravenous injection, which many people feel is beneficial when dealing with cats.
Total intravenous anesthesia (TIVA )
The concept of maintaining general anesthesia using only intravenous agents has developed rapidly over the past few years. Major benefits offered by this technique, when compared to inhalational agents, include improved controllability of anesthesia and lack of environmental contamination with
