Diseases Flashcards
T or F: Dogs being treated with ACE inhibitors and diuretics for CHF can be anesthetized
True; animals with untreated CHF should not be anesthetized
What are you hemodynamic goals for anesthetizing patients with mitral valve regurgitation?
- Slight reduction in preload may reduce regurgitant flow
- Avoid acute increases in afterload—> Vasodilators/most anesthetics reduce afterload
- Maintain contractility
- HR can be increased slightly; avoid bradycardia b/c results in long systole and worsens regurg!
- Rhythm: maintain sinus rhythm
- Avoid severe tachycardia and hypotension
What are your anesthetic goals for a patient with MR?
- Do not fluid overload patient (no boluses); Should receive lower Na fluids (2.5% Dextrose + half strength LRS) at lower rate
- avoid sinus bradycardia - don’t be afraid to use anticholinergics
- maintain myocardial contractility, tx hypotension using beta1 agonist (dobutamine, dopamine)
- slight vasodilation is acceptable, avoid peripheral vasoconstriction —> don’t use alpha 2’s
- minimize excitement - increased catecholamine release may cause vasoconstriction
What are some anesthetic considerations for pre-medding a patient with MR?
- Ace: low dose, will reduce afterload and provide sedation/minimize catecholamine-induced arrhythmias
- Opioids: indicated for painful procedure and maintain contractility; however, may cause sinus bradycardia so can add anticholinergic to premed protocol if high dose used
- Benzos: produce minimal cardiopulmonary depression, can cause paradoxical excitement, so should be avoided in dogs that are not depressed
What are some anesthetic considerations for induction of a patient with MR?
- Propofol: causes some periph vasodilation, but can depress myocardial contractility, should be given slowly, can add in a benzo
- Alfaxalone: should be given slowly over 60 seconds, same CV effects as prop
- Ket-diazepam or Ket-midaz: causes transient sinus tachycardia, will increase BP and CO
- Etomidate: most heart-friendly; maintains MAP, HR, and CO; however, rough induction (gagging, myoclonus); indicated in patients w/ enlarged heart and show CHF signs
- Neuroleptanalgesia (diazepam/hydro or diazepam/fentanyl): maintains myocardial function, bradycardia may occur, poor quality induction in non-depressed patients
Which drugs should be avoided in patients with MR?
- Xylazine
- Medetomidine
- Dexmed
- Phenylephrine (vasoconstrictor)
What should be used for maintenance in MR patients?
Inhalants; either Iso or Sevo
What are the hemodynamic goals for patients with HCM?
- Maintain preload in cats without CHF
- Afterload should be increased, if possible
- Myocardial depression is preferred
- HR should be within normal range; avoid sinus tachycardia, as it can worsen the LV outflow obstruction
- Maintain sinus rhythm
- Avoid severe tachycardia and hypotension
What are some anesthetic considerations you should have in a patient with HCM?
- Adequate diastolic filling can be accomplished by large ventricular volume and sinus rhythm (don’t decrease pre/afterload)
- Ketamine should be avoided b/c it increases contractility and HR, as well as myocardial oxygen demand
- Control dyrhythmias prior to pre-medding
- Minimize stress and excitement b/c of catecholamine release that will increase HR and contractility
- Beta and Ca channel blockers that patient is being treated with should be maintained up until the day of anesthesia
What are the recommended pre-meds for patients with HCM?
- Opioids: minimal effects on myocardial contractility, preload or afterload; may cause sinus bradycardia, can give w/ glycopyrrolate (not atropine) - less sinus tachycardia
- Benzos: minimal cardiopulm depression, can be given w/ induction agent IV to minimize risk of excitation
- Dexmed or medetomidine: shown to eliminate outflow tract obstruction, dexmed can be used for chemical restraint
Which pre-med agent is contraindicated for use in cats with HCM?
Ace
What are the recommended induction agents for patients with HCM?
- Propofol: if etomidate not available, used in combo w/ benzo to reduce peripheral vasodilation
- Etomidate: most heart-friendly agent; best choice if available
- Neuroleptanalgesia: maintain myocardial function, anticholinergic can be added to combat bradycardia, should only be used in HCM cats that are very depressed
What method of induction should be avoided in HCM cats?
Mask induction with sevo or iso b/c of the stress and excitement it causes
What drugs should be avoided in cats with HCM?
- High to moderate doses of ace (pronounced vasodilation)
- Ketamine (increases ketamine and contractility)
- Atropine (increases heart rate markedly)
- Thiopental (arrhythmogenic)
What agents are used for maintenance in an HCM cat?
- Iso or sevo
- Phenylephrine in cats that develop hypotension - alpha agonist that increases peripheral resistance
- Dobutamine/dopamine should be avoided
What are the hemodynamic goals for patients with DCM?
- Maintain or reduce preload depending upon severity
- Avoid increases in afterload
- Maintain or increase contractility
- Maintain normal HR
- Control dysthymias
- Do not increase myocardial oxygen requirement by avoiding tachycardia and hypotension
What are possible sequela of CKD to make sure are managed accordingly prior to anesthesia?
- Change in BBB leading to drug sensitivity
- Hypovolemia and dehydration
- Metabolic acidosis
- HyperK
- HyperMg
- HypoCa
- Anemia
- Hypertension but reduced cardiac reserve
- Susceptibility to vagal-induced bradycardia
What are some anesthetic considerations you should have when anesthetizing a patient with CKD?
- The kidney’s high metabolic rate makes it prone to hypoxemia and hypotension
- Anesthesia works on the RAAS to reduce renal blood flow and redirect away from cortex
- also causes reduced GFR and renal blood flow —> light planes of anesthesia preserve renal autoregulation
- minimize stress/excitement
What are your anesthetic goals in a patient with CKD?
- Maintain renal blood flow
- Avoid hypovolemia
- Avoid renal vasoconstriction
What are the recommended premeds for a CKD patient?
- Anticholinergics: no significant effect on renal function, must be given to patients w/ high vagal tone
- Ace: may minimized sympathetic stimulation, can produce hypotension at high doses but low doses are renoprotective
- Benzos: no renal effects, minimal cardiopulm effects
- Opioids: no direct effect on kidneys, antidiuretic effect
Why should alpha 2s be avoided in CKD patients?
Because they will cause short-term glucosuria and polyuria, and they can cause peripheral vasoconstriction and marked reduction of CO
Which drugs should be used for induction of a patient with CKD?
- Propofol: no direct kidney effects, though can cause hypotension, so give slow and with pre-med
- Thiopental: decreases renal blood flow and GFR in proportion to decrease in BP, can minimize hypotensive effect if given slowly, however, propofol is preferred b/c is more quickly metabolized
- Etomidate: minimal CV effects, hemolysis risk is a concern in anemic patients
- Neuroleptanalgesia: fluid therapy is a must d/t antidiuretic effects
Why are dissociatives, such as ketamine and tiletamine, not recommended for induction agents in patients with CKD?
Because they cause sympathetic stimulation, which causes vasoconstriction, and in turn, decreased renal blood flow; also has prolonged effect in cats b/c is almost exclusively excreted by kidneys
Maintenance with inhalants, such as sevo and iso, is recommended over injectables in CKD patients..why?
- Excretion is not dependent on kidneys
- recovery is faster
- high concentration of oxygen and ventilation can be supported
What drugs should be avoided in CKD patients?
- NSAIDs
- Alpha 2s
- Ketamine (cats)
- Telazol (cats)
What are important monitoring principles for anesthetic patients with CKD?
- Blood pressure - manage hypotension by decreasing vaporizer setting, give fluid boluses, and administering positive inotropes (dobutamine preferred)
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Most important factor = fluid administration
- high rate (20 ml/kg/hr) of IV crystalloids should be administered in patients that do not have CHF, pulm edema or are anuric
- can initiate active diuresis in those with inadequate urine output using furosemide or mannitol
What are you anesthetic considerations for a patient with diabetes mellitus?
- Pre-anesthetic bloodwork should include: fasting BG, ketones, serum electrolytes, BUN, hepatic enzyme levels, creatinine, and acid-base values
- gentle handling and sending patient home ASAP after procedure
- shorter fasting times
- well-regulated at home might become hyperglycemic at the hospital due to stress
What are your anesthetic goals for a patient with DM?
- Prevent hypoglycemia
- Maintain fluid and electrolyte balance
- Control severe hyperglycemia and prevent ketoacidosis
What are some good choices for pre-meds in a patient with DM?
- Low dose Ace
- Benzos
- Opioids: when added to either ace or benzos
What are good choices for induction agents for patients with DM?
- Propofol: may be best choice b/c short acting and doesn’t have “hangover effect”
- Alfaxolone: rapid clearance/shorter recovery time
- Thiopental: may cause further increase in liver enzyme levels
- Etomidate
- Neuroleptanalgesia: only in depressed patients; not as good as prop/alfaxolone
What agents should be used for maintenance in DM patients?
Iso or sevo; though sevo has a quicker recovery time
What drugs should be avoided in patients with DM?
- Alpha 2’s (hyperglycemia and hypoinsulinemia)
- Dissociatives (mild hyperglycemia due to sympathetic stim)
- Mask induction (stress leading to sympathetic stim)
What are some important monitoring principles in patients with DM?
- BG levels should be checked every hour or 30 minutes in unstable patients
- if >300 mg/dL, regular insulin should be given
- if <100 mg/dL, increase dextrose infusion rate or bolus 50% dextrose
- Hypoglycemia is more life threatening during anesthesia than hyperglycemia
- Oral feeding and routine insulin therapy should resume if possible right after recovery
What are some important anesthetic considerations for patients with hepatic insufficiency?
- May be hypoglycemic, so BG should be monitored
- May be hypoproteinemic, so will be more active (free) form of anesthetic drugs present
- Hypoalbuminemia may have decreased colloid oncotic pressure, so should use colloids (not crystalloids) for patients with albumin levels < 2.0
- Run coag panel if patient shows evidence of bleeding tendencies
- Anesthetic agents will have prolonged effects, so drugs that are reversible, have minimal effect on hepatic blood flow, and have a short duration of action are preferable
What are you anesthetic goals in patients with hepatic insufficiency?
- Maintain blood flow to the liver
- Maintain arterial blood pressure above 60 mmHg
- Maintain eucapnia and prevent hypoxemia
What are the pre med recommendations for patients with hepatic insufficiency?
- Benzos
- Opioids: reversible, minimal CV effects
What pre-med agents should be avoided in patients with hepatic dysfunction?
- Ace: longest duration of action and hepatic dysfunction already causes increased free concentration of drug
- Alpha 2s: reduce CO, vasoconstriction, sinus bradycardia, and hypotension (reduces blood flow to liver)
What are the recommended induction agents to be used in patients with hepatic insufficiency?
- Propofol: has extrahepatic metabolism as well, rapidly eliminated (except in cats)
- Thiopental: hypoalbuminemia will result in more active form
- Dissociatives: low doses are fine, except in patients showing CNS signs
- Etomidate
- Neuroleptanalgesia
What drugs should be used with caution in patients with hepatic insufficiency?
- Ace
- Alpha 2s
- Ketamine
- Thiopental
What are some important monitoring considerations in anesthetic patients with hepatic insufficiency?
- BP should be monitored and colloids and positive inotropes should be used if needed
- Should receive high concentration of O2
- Eucapnia should be maintained, as hypoventilation will decr hepatic perfusion
- BG levels should be checked at the end of anesthesia and hours into recovery
- Hypothermia can further prolong the already longer effects
