Feline Anesthesia Richard M. Bednarski, DVM, MSc The Ohio State University College of Veterinary Medicine Current Issues in Feline Anesthesia Chemical Restraint Protocols Trap, Neuter, Release Anesthetic Protocols Early age spay/castration protocols Analgesia and Analgesics Sedation/Moderate Restraint Acepromazine Alpha 2 agonists: Medetomidine, Xylazine Neuroleptanalgesia Ketamine (low dose) Telazol (low dose) Acepromazine Mild sedation Vasodilation Antiarrhythmic Antiemetic Combines well with opioids to produce moderate sedation and restraint 0.05-0.2 mg/kg No antagonist available
Alpha 2 Agonists: Xylazine, Medetomidine Moderate sedation and chemical restraint Reversible Combine well with opioids Vomiting Cardiovascular alterations Medetomidine (Domitor) Cardiovascular effects make it best for use in young, healthy cats 30 minute -1.5 hour duration Reversible with Atipamezole (Antiseden) Can be combined with opioids and/or ketamine for moderate restraint to surgical anesthesia Medetomidine (Domitor) in Cats Dosage: 40-100 µg/kg for moderate to significant restraint Duration of action: 30-90 minutes Midazolam Water soluble benzodiazepine Very similar pharmacokinetics and pharmacodynamics to Diazepam Minimal cardio-respiratory side-effects Rarely useful by itself for sedation Best when combined with an opioid for mild sedation/restraint Midazolam Useful when acepromazine is contraindicated Most useful in middle aged to older animals
Sedation generally better than in young healthy animals Useful in sick or debilitated animals Neuroleptanalgesia One of the following Acepromazine, Alpha 2 Agonist, Midazolam combined with one of the following Morphine, Hydromorphone, Oxymorphone, Buprenorphine, Butorphanol Opioids Agonists Morphine, hydromorphone, oxymorphone, fentanyl, meperidine Agonist/Antagonists Butorphanol, Buprenorphine, Pentazocine Antagonists Naloxone Parenteral Opioid Dosages (mg/kg) Morphine: 0.2-1.0 Hydromorphone: 0.02-0.1 Fentanyl: 0.002 Fentanyl Infusion: 1-6 µg/kg/hr Oxymorphone: 0.02-0.1
Parenteral Opioid Dosages (mg/kg) Butorphanol: 0.2-0.8 45 minutes duration Buprenorphine: 0.005-0.02 6-8 hrs duration Tiletamine/Zolazepam 50:50 combination of a benzodiazepine tranquilizer and a dissociative anesthetic Variable dosages for mild sedation to surgical anesthesia (2-6 mg/kg) Prolonged recovery at the higher dosages Useful prior to gas anesthesia or combined with other chemical restraint drugs Short Term Injectable Anesthesia in Cats Acepromazine, Opioid, Ketamine Diazepam and Ketamine Propofol Thiopental Feral Cat Trap/Neuter/Return (TNR) Anesthesia IM administration Rapid and predictable surgical anesthetic duration and effect Economical Reversible Wide safety margin Provide post-operative analgesia
Feral Cat TNR Anesthesia Telazol, Xylazine, Ketamine (TKX) Medetomidine, Ketamine, Butorphanol Telazol/Ketamine/Xylazine To one vial of Telazol add 4 ml ketamine and 1 ml 10% (LA) Xylazine Dose 0.015 ml/lb body weight Note: Accurate body weight is essential to safe dosing Medetomidine, Ketamine, Butorphanol Medetomidine: 60 µg/kg, IM Ketamine: 5 mg/kg, IM Butorphanol: 0.2 mg/kg, IM Can be mixed in same syringe Atipamezol to reverse medetomidine Wait at least 45 minutes after medetomidine Early Age Spay/Neuter Anesthesia IM administration Rapid and predictable surgical anesthetic duration and effect Economical Reversible Wide safety margin Provide post-operative analgesia
Early Age Spay/Neuter Anesthesia Tiletamine/Zolazepam Useful alone in most males but occasionally must be supplemented with inhalants Must be supplemented with inhalants for ovariohysterectomy Recovery can be prolonged Early Age Spay/Neuter Anesthesia Mask with isoflurane or sevoflurane followed by intubation Uncuffed tube provides relatively larger diameter airway Can administer butorphanol for post operative analgesia Advantage is relatively quick and predictable recovery time Behavioral Response to Pain Anxiety and Fear Depression and lethargy Sleeplessness Quiet and withdrawn Especially Cats Inappetence Vocalization Pain Assessment Subjective Anthropomorphism: We assume if it would be painful to us it would be painful to the animal Obvious examples of painful procedures Ear ablations, fractures, joint invasion, extensive tissue
excisions, amputations (including onychectomy) Analgesic Drugs Opioids NSAID s Local Anesthetics Alpha 2 agonists Ketamine Others Buprenorphine Oral administration 10 µg/kg BID Approximately 0.1 ml from a TB syringe per 3 kg body weight Excellent acceptance by cats Good owner compliance Transdermal Fentanyl Dog VS. Cat Location of Patch Warm water blankets, forced air warmers Abuse Potential Transdermal Fentanyl Duragesic Patch - Janssen Pharmaceutica 25, 50, 75, 100 µg/hr strength Onset Cats: 10-18 hrs Dogs: 18-24 hrs
Duration: 3 days/patch NSAID S Inhibit cyclooxygenase Prostaglandin synthesis is reduced COX - 1 (constitutive): Normally present Involved in normal renal, GI, platelet function COX -2 (inducible): Induced by tissue damage Inflammation and pain NSAID S Dosages (mg/kg) Carprofen: 4.0 given once Ketoprofen: 2.0 SC, p.o. initially followed by 1.0 daily for 5 days Meloxicam: 0.2 SC, p.o. initially followed by 0.1 daily for 2-3 days Local Anesthetic for Declaw Procedure Subcutaneous injection just proximal to carpus Palmar and Dorsal surfaces Ropivacaine (Naropin) or Bupivacaine Use the 0.2 % or 0.25% preparation Dosage = 2.0 mg/kg Approximately 1.5 ml per leg per 3 kg cat Short-term Injectable Anesthesia in Cats Acepromazine/Opioid and Ketamine Diazepam and Ketamine
Thiopental Propofol Long-term Injectable Anesthesia in Cats High dose ketamine High dose ketamine with acepromazine Medetomidine and ketamine Medetomidine and ketamine with opioid Telazol Telazol/Ketamine/Xylazine Propofol Infusion Isoflurane Sevoflurane Halothane Desflurane Nitrous Oxide Inhalation Anesthetics Anesthetic Induction Mask or Chamber Thiopental Diazepam or Midazolam and Ketamine Propofol Feline Intubation Laryngoscope Straight Blade is preferable Stylet
0.1 ml 2% topical Lidocaine via TB syringe