Anesthetic Issues in Animals with Cardiac Dysfunction Flashcards
What are the most common congenital defects?
PDA
Septal defects
Stenotic valves
What are some acquired diseases?
Valvular dysfunction
Myocardial failure
Conduction disturbances
What is the most common congenital problem in dogs?
PDA
What dogs get valve disease?
Small, geriatric
What dogs get DCM?
Large, giant breeds
What dogs have conduction disturbances?
Boxer dogs
What is the common heart problem in cats?
HCM
What is a congenital defect in horses?
VSD
What are acquired cardiac problems in horses?
Conduction disturbances
Valvular disease
What should be done in a physical exam?
Quiet room
Auscultate for a long time
Both sides
Feel pulses at the same time
Check for: muffled heart sounds, cough, edema, ascites, jugular pulses, wide forelimb stance, pale MM, cyanosis
Exercise the animal and see who gets tired first
What should be used for objective analyses?
ECG, chest rads
Echo
Chem
CBC
What are the anesthetic rules of thumb?
Avoid increased myocardial oxygen demand
Avoid fluid overload
Maintain adequate oxygen delivery
Maintain HR near that of awake at rest level
Inotropes are great for poor contractility
Do not suddenly change cardia meds
Correct arrhythmias if possible
Pre-oxygenate
Attention to detail and monitoring are as important as drug choices
How do you calculate CO?
CO = HR x SV
How do you calculate MAP?
MAP = CO x SVR
What are anticholinergics indicated for?
Bradyarrhythmias, cardiac arrest
Useful in patients whose CO tends to be rate dependent (pediatrics, cats)
What can anticholinergics cause?
Tachycardia that will not be tolerated by a cardiac patient
What is acepromazine useful in?
Animal with dilated cardiomyopathy
What is ace not great to be used in?
Animals with HCM or CHF
Which benzo is nice for cardiac patients?
Midazolam
What do opioids cause?
Bradycardia, otherwise there is minimal impact on CO
What does opioid reduce?
Inhalant requirements
Alpha-2 adrenergic agonists (xylazine and dexmedetomidine) are not recommended in cardiac patients except what?
HCM cats and horses
What is highly recommended in cardiac patients with local anesthetics?
Regional use
What do dissociatives do?
Increased cardiac oxygen consumption and HR
Dissociatives are useful in very low doses except in what?
Cats with HCM
What is the induction drug of choice in animals with significant cardiac dysfunction?
Etomidate
What does thiopental cause?
Tachycardia
Tachyarrhythmias
What is the second drug of choice in animals with cardiac dyfunction?
Propofol but only in low dosages
What is alphaxalone?
Synthetic neuroactive steroid that interacts with GABA receptors to produce anesthesia and muscle relaxation
What is needed before induction with alphaxalone?
Sedation
What can alphaxalone cause?
Apnea or excitement
What do inhalants cause?
Dose-dependent reductions in CO and BP
What should be avoided with IV fluids?
Fluid overload
Hypertonic saline
What can be used for monitoring?
ECG, blood pressure direct measurement
Central venous pressure
Pulse oximeter
Capnograph
What should be used in patients with poor contractility?
Inotropes
What are inotropes not a good idea to use in?
Hypertrophic patients
What are the side effects of furosemide?
Dehydration and hypokalemia
What are the side effects or spironolactone?
Hyperkalemia
What are side effects of ACE inhibitors (Enalapril/Benazepril)?
Arterial vasodilation
Hypotension
What are the side effects of digoxin?
Positive inotrope
Increased arrhythmogenesis
What are the side effects of calcium channel blockers (Diltiazem)?
Hypotension/bradycardia
What are the side effects of propranolol/sotalol (antiarrhythmic agents)?
Bradycardia, hypotension
What are the side effects of procainamide (antiarrhythmic agents)?
Decreased myocardial contractility, bradycardia
What do you medicate with if there is mild to moderate valvular insufficiency?
Opioid + benzo or low dose ace
Preoxygenate
What is used for induction with mild to moderate valvular insufficiency?
Propofol or ketamine/diazepam or alphaxalone
What is used for maintenance with mild to moderate valvular insufficiency?
Iso or sevo
What rate should IV fluids be give with mild to moderate valvular insufficiency?
2-5 mg/kg/hr
What should be used for premed with dilated cardiomyopathy?
Opioid + benzo
Preoxygenate
What should be used for induction with dilated cardiomyopathy?
Fentanyl/propofol or fentanyl + ketamine/diazepam or etomidate
What should be used for maintenance with dilated cardiomyopathy?
Minimal iso or sevo
At what rate should fluids be give with dilated cardiomyopathy?
2-5 mg/kg/hr
What should be used for BP support with dilated cardiomyopathy?
Inotropes
What should be used to premed a puppy with PDA?
Opioid + low dose ace or benzo
What should be used to maintain HR in a puppy with PDA?
Anticholinergics
What should be used for induction of a puppy with PDA?
Low dose propofol or ketamin/diazepm or etomidate if in failure
What should be used for maintenance in a puppy with PDA?
Minimal iso or sevo
What is the normal HR in a dog?
60-160
What is the normal HR in a cat?
120-220
What is the normal HR in a horse?
25-45
What is the normal HR in a cow, sheep,and goat?
60-80
What is the normal HR in a pig?
60-110