Lect 11

• Anesthesia is a state of controlled, temporary loss of sensation or awareness that is induced for medical purposes.
• Anesthesia is used daily in most veterinary practices for diverse range of indications including sedation, tranquilization, immobility, muscle relaxation, unconsciousness, pain control, surgery, dentistry, grooming, diagnostic imaging, wound care, and capture/transport of wild animals.
• Morphine is a drug that causes neuroleptanalgesia, which is an analgesic and tranquilizer combination.
• Butorphanol is a drug that causes neuroleptanalgesia, which is an analgesic and tranquilizer combination.
• Acepromazine is a drug that causes neuroleptanalgesia, which is an analgesic and tranquilizer combination.
• Phenothiazine is a drug that causes neuroleptanalgesia, which is an analgesic and tranquilizer combination.
• Anesthesia can be categorized into four major stages: light, moderate, deep, and hypnosis/narcosis.
• Anesthetic overdose can lead to sedation, general anesthesia, and anesthetic crisis.
• Anesthetic and Adjunct Drugs are different types of drugs used in anesthesia.
• An Anesthetic is a drug used to induce a loss of sensation with or without unconsciousness.
• An Adjunct is a drug that is not a true anesthetic, but that is used during anesthesia to produce other desired effects such as sedation, muscle relaxation, analgesia, reversal, neuromuscular blockade, or parasympathetic blockade.
• The anesthetic protocol, dose, and route are chosen by the Veterinarian.
• Many clinics have a routine protocol, but it is important to consider all aspects of the patient’s minimum database.
• Pre-anesthetic Medications are used prior to the administration of an anesthetic agent to make anesthesia safe and more agreeable to the patient.
• Routes of administration for Pre-anesthetic Medications include SC (slowest onset, longest duration), IM (faster onset, shorter duration), and IV (fastest onset, shortest duration).
• Tranquilizers used in Neuroleptanalgesia include Acepromazine, Diazepam, Midazolam, Xylazine, and Dexmedetomidine.
• Neuroleptanalgesia is a profound state of analgesia and sedation induced by simultaneous administration of a narcotic analgesic (opioid) and a tranquilizer, characterized by profound sedation, immobilization, intense analgesia without loss of consciousness.
• Acepromazine (ACE) protects against arrhythmias.
• Diazepam (Valium R) is a Benzodiazepine (BDZ) and is commonly used with ketamine to induce anesthesia in small animals and horses.
• Acepromazine (ACE) is not an analgesic and causes peripheral vasodilation that leads to hypotension, decreased heart rate (bradycardia), and hypothermia.
• Tranquilizers provide pre-operative sedation and amnesia and help to prevent or counteract the CNS stimulation.
• Zolazepam is a Benzodiazepine (BDZ) and is available only as a component of Telazol R, a powdered product reconstituted with sterile water, used in cats.
• Acepromazine (ACE) is used as an antiemetic and has less pronounced sedation in cats.
• Benzodiazepines (BDZs) cause adverse effects such as disorientation and excitement in young, healthy dogs, dysphoria and aggression in cats, muscle fasciculations in horses, and ataxia and recumbence in any large animal.
• Acepromazine (ACE) does not cause significant respiratory depression and is antiemetic.
• Midazolam is a Benzodiazepine (BDZ) and is commonly used with ketamine to induce anesthesia in dogs, small mammals, and birds.
• Opioids provide analgesia.
• Benzodiazepines (BDZs) are used as pre-anesthetic medications and produce anxiolytic, anticonvulsant, and muscle relaxant effects, potentiating general anesthetics.
• Anticholinergic agents prevent profuse salivation and bradycardia.
• Tranquilizers provide pre-operative sedation and amnesia, and help to prevent or counteract the CNS stimulation caused by some anesthetics.
• Central muscle relaxants provide muscle relaxation during anesthesia.
• Butorphanol is a partial agonist (μ), plus (
• Opioids are commonly used for premedication and perioperative analgesia.
• Pre-anesthetic medications may include agonists, partial agonists, or mixed agonist-antagonists.
• Morphine is a safe, effective analgesic for most small animal patients and provides analgesia for mild and severe pain.
• Most general anesthetics are not analgesics and must provide analgesic pre- and post-operatively.
• Tranquilizers are used to calm and sedate excited animals, minimize adverse drug effects, reduce dose of concurrent drugs, and provide smoother anesthetic induction and recovery.
• Butorphanol is a partial agonist (μ), plus (k) and provides analgesia, reversal of sedation and respiratory depression.
• Pre-anesthetic medications are used to sedate, reduce anxiety, obtain an additive or synergistic effect, counteract certain adverse effects of anesthetic drugs, and relieve from pain.
• Pre-anesthetic medications generally include combinations of drugs from multiple categories such as opioids, phenothiazine tranquilizers, benzodiazepines, α2-agonists, anticholinergics, and muscle relaxants.