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60 Cards in this Set
- Front
- Back
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four big things that can be affected in the CV system by anesthetic drugs |
HR and rhythm BP SVP |
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2 things that make up blood pressure |
CO and SV |
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what 3 things make up SV |
preload afterload contracility |
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name 5 common premidcation that could be used in cardiac patients |
opioids anticholinergics benzodiazepines dexmedetomidine acepromazine |
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what effects does acepromazine have on the CV system |
-- there is a little effect on HR: HR may increase when BP goes down. -- it is weak antiarrhythmogenic -- it decreases BP through SVR |
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what type of drug is dexmedetomidine |
alpha 2 agonists |
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what type of effects does dexmedetomidine have on the CV system |
increases SVR --> compensatory bradycardia --> bradycardia is maintained when the drug acts centrally --> CO decreases |
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what type of heart arrhythmia could happen with dexmedetomidine |
1st and 2nd degree AV block |
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name two benzodiazepine drugs |
diazepam midazolam |
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what effects do benzodiazepines have on the CV system |
negligible effects on the CV system |
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name two anticholinergics which one is used more commonly and why |
atropine - less expensive and acts faster glycopyrolate |
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how do anticholinergics effect the CV system |
-- parasympatholytic --> increased HR -- BP can increase b/c HR increases while SVR does not change -- 2nd degree AV block can happen transiently after administration. sinus node responds faster than the AV node |
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when a patient is bradycardic and hypotensive what can be done to try and increase the BP |
increase the HR |
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what effects do opioids have on the CV system |
- bradycardia in dogs / tachycardia in cats at high doses - little effect on BP unless there is histamine release (vasoconstriction) |
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which opioids are bad for histamine release |
morphine < meperidine |
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how should meperidine be given |
SC or IM to decrease histamine release |
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what 4 drugs are commonly used for induction |
propofol ketamine alfaxalone etomidate |
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what effects does propofol have on the CV system |
no effect on HR or rhythm decreases BP: decreases CO and SVR (vasodilation) |
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what effects does ketamine have on the CV system |
The drug acts on the sympathetic NS --> increase HR and BP ( through CO - SV and contractility) |
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what happen when the sympathetic NS is not working well and ketamine is used |
it is negative inotrope -- no effect on HR, decreased contractility, SV, CO and BP. |
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what are two examples of situation where the patient may not have good sympathetic tone |
- patients that have been given an alpha-2 agonist - shock: the SNS has been maximally stimulated |
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what is the effect of alfaxalone on the CV system |
increases HR decreases BP through CO (SV and contractility) + SVR (vasodilation) |
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what type of drug is etomidate |
GABA agonists (like propofol) |
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what effect does etomidate have on the CV system |
there is little effect on the CV system |
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what effects do the inhalants iso and sevo have on the CV system |
little effect on HR at clinical [ ]s BP decreased |
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it is worth trying to turn down the inhalant when the patient is bradycardic |
no -- it is worth it when the patient is hypotensive |
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name two drugs that could be used to treat bradycardia and heart blocks |
- anticholinergics: atropine is shorter acting - sympathomimetic: dopamine |
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what does dopamine act on to increase HR |
beta 1 ** and alpha 1
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what can be done when a patient is tachycardic |
** treat the cause ** - hypovolemia, tachyarrhythmias increase vagal tone (edrophonium) Ca channel blockers beta-adrenergic blockers |
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which Ca channel blocker would be used |
diltiazem |
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what type of drug is edrophonium |
ACE inhibitor little to no effect on myocardial contractility |
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which beta adrenergic blocker is best for tachycardia |
esmolol -- has a very short half life and can be titrated to effect while the patient is under anesthesia |
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what is the first step in treating tachycardia |
fluids -- but you have to be careful in cardiac patients b/c of V overload. |
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what V of what type of fluids would be used |
small volume (3-5ml/kg) boluses of crystalloids would be given to see if the patient responds |
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what type of fluid holds BP better/longer |
colloids |
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inhalants cause a dose dependent _________ |
hypotension |
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what is balanced anesthesia |
concurrent administration of several drugs so that no single drug is given in a dosage sufficient to produce toxicity during or after surgery |
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what can be used to decreased anesthetic requirements (general concept) |
local or regional anesthesia |
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how could an opioid be used during balanced anesthesia |
high dose IV (CRI) for analgesia |
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what is the main down side of opioid CRI |
causes significant respiratory depression mechanical ventilation will probably be required |
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what is different about opioids in cats (as part of balanced anesthesia) |
there is a limited decrease in anesthetic requirement tachycardia, hypertension, hyperthermia b/c of sympathetic stimulation and the potential for a rough recovery |
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what does ketamine do in balanced anesthesia |
CRI -- decreases ansthetic requirement in a dose dependent manner.
improves CV function (in dogs -- unknown in cats) |
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which antiarrhythmic drug is also used in balanced anesthesia |
lidocaine is used IV to decrease anesthetic requirements in a dose dependent manner in dogs |
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what does lidocaine do in cats |
increases BP and decreases CO -- they don't know if it is beneficial or not. |
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is lidocaine bad for cats |
some older studies have show lidocaine toxicity in a colony of cats
there are new studies that show that the toxicity is not worse than other species. |
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what are the benefits of using dexmedetomidine in balanced anesthesia |
reduced anesthetic requirement, BUT there is dose dependent bradycardia, vasoconstriction and decreased CO AND
dogs: CV function was similar to iso alone at a higher dose cats: CV function is worse than w/ iso alone at a higher dose |
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how does nitrous oxide work in balanced anesthesia |
it is a weak anesthetic agent that reduces the anesthetic requirements in dogs. it causes sympathetic stimulation -- dogs: increased HR, BP and CO -- cats: increases HR, BP and no change in CO |
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what is the best choice for balanced anesthesia in dogs |
opioids -- as long as there is mechanical ventilation available |
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what is the best choice for balanced anesthesia in cats |
unknown what is best - ketamine, CRI, nitrous |
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name 2 beta-1 adrenergic agonists how do they affect the heart |
dopamine, dobutamine positive inotropes |
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name 3 alpha 1 adrenergic agonists how do they affect the CV system |
phenylephrine, NE, epinephrine vasoconstriction |
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which alpha 1 adrenergic agonists would be used as a first choice in small animals |
phenylephrine |
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which alpha 1 adrenergic agonists would be used as a "desperate measure" |
epinephrine |
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4 important things that should be monitored for CV function |
- HR - pulse rate - heart rhythm - CO |
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how could HR be monitored |
ECG esophageal stethoscope |
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how would pulse rate be monitored |
doppler oscillometric NIBP invasive BP pulse oximeter |
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how is CO monitored under anesthesia |
- changes are estimated from changes on BP and from subjective assessment of SVR (perfusion parameters and CVP) |
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what should a pre anesthetic work up for a suspected heart disease patient look like |
regular workup: Hx, PE, lab work specific workup: chest rads, ECG, echo |
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what should be done before anesthesia for a heart disease patient |
treat CHF is possible optimize hydration prior to anesthesia keep the patient on it's heart meds (except ACE inhibitors) |
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why would ACE inhibitors not be given the day of anesthesia |
it may result in severe refractory hypotension when combined with inhalant anesthesia |
