Coexisting Disease and Special Considerations
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Hyperthermia
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HCM
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Feral Cat Programs
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Peri-Operative Analgesia
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Declaw Pain
Metabolism of Drugs
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Cats have relatively deficient hepatic glucuronidation mechanism
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Fewer hepatic UDP-glucuroninosyltransferase (UGT) isoforms, perhaps due to strict carnivorous diet and lack of exposure to
plants and phytoalexins
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Lack of morphine-6-glucuronide formation
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Toxicity of acetaminophen and other phenols and NSAIDs
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Anesthetic Hyperthermia in Cats
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Drugs and stressors implicated
• Some opioids implicated:
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hydromorphone, oxymorphone, fentanyl (Duragesic), morphine
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Dose dependent (±)
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Reversal of opioid with antagonists
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Symptomatic / Supportive treatment
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Vasodilation, sedation, active cooling
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Monitoring to avoid over-correction
Hypertrophic Cardiomyopathy
• Subclinical HCM is a nasty silent killer!
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It converts otherwise very safe and useful anesthetic techniques into a substantial threats to survival
• HCM plus ketamine or Telazol kills lots of cats! So can HCM plus isoflurane!
• No adequate and practical screening tests as yet.
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HCM is a failure of relaxation (lusitropy), rather than contraction
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Limited ventricular volume and limited coronary blood flow
• Priorities:
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slow heart rate
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maintain preload
Anesthetic Techniques for Cats with (suspected) HCM
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Minimize stress and excitement
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Avoid acepromazine (to maintain preload)
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Avoid anticholinergics
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Benzodiazepine (midazolam or diazepam, potential for excitement)
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Medetomidine (controversial ?) for HCM with LVOT obstruction
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Opioids (butorphanol, hydromorphone, buprenorphine, fentanyl)
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Propofol, Etomidate
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Halothane, Isoflurane (worst), Sevoflurane (best)
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Fluid therapy to maintain preload, but limited with any signs of heart failure
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Monitoring and Support
NSAIDs in Cats
• Meloxicam, 0.1 mg/kg, q24h. For 2-3 days mg/cat, oral suspension, one drop q24h)
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EU approved label for chronic administration of meloxicam in cats
• Ketoprofen, 1.0-2.0 mg/kg, SC, IM initially, then 0.5-1.0 mg/kg, PO, SC, q24h
• Carprofen, 1.0 mg/kg, PO, (1-2 doses only), q24h
• "Old School" - Aspirin in cats: "Just say NO!" Much longer dosing interval than in other species, leading to a greater risk
of overdose (due to error) and greater toxicity than in dogs. Better options.
