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Dopamine is binds to adrenergic as well as double main receptors we typically say d 1 alpha 1 and beta 1 and we typically say that which receptors are bound depend on the dose with increasing doses you go from d1 to beta 1 to alpha 1 classically taught that way but in reality and clinically there really isn’t that nice gradation it’s given as an iv infusion of
2 to 5 mike’s per kilo per minute it increases your cardiac contractility as well as therefore your output it a reaches your heart rate it is a chrono trope positive control it increases your urine output and at high doses it causes vasoconstriction there’s been multiple randomized control trials on the use of dopamine to increase urinary output as specifically
In post cardiac surgery and even though dopamine may increase your urine output which makes you feel better to see that your post cardiac surgery patient is making urine it actually doesn’t change any renal outcomes side effects however do include tachycardia as well as other arrhythmias and i have seen in many a time where we started dopamine to try to improve
Urine output and even though it does that we’ve probably or may have caused a patient to go into atrial fibrillation it used to be recommended as an agent that could be used for improvement in blood pressure in septic shock but the new secm guidelines does not recommend that as the first-line agent there was a randomized control trial trial sorry in septic shock
And what it basically found that was that eva fed in dopamine pretty much give you the same blood pressure improvement but dopamine was had a higher rate of of adverse effects specifically hoa weakness so we again don’t go for it as a first line agent epinephrine binds all for hydrologic receptors alpha 1 alpha 2 beta 1 and beta 2 and as such it causes bronco
Bronco dilatation i apologize for that it does not cause bronchoconstriction it causes bronchodilation the other beta 2 system because is these a constriction via alpha 1 system it increases your contractility via your beta 1 as well as can cause a tachycardia if you have a beta 1 now i will say that these are all traditional teachings it can also at low doses
10 to 20 nanos per kilo per minute actually cause vasodilation it inhibits mast cell degranulation and therefore it’s the drug of choice for an athlet anaphylactic shock often is given iv in the acls guidelines it’s one milligram during cardiac arrest for bradycardia you often see it used as to the 10 mics per minute as well as for i’m a trophy and when somebody
Doesn’t have an iv and they come in with having some severe anaphylaxis with bronchoconstriction you often give it intramuscularly 300 micrograms right on the lateral part of the thigh repeated every about 20 minutes about norepinephrine also known as levophed binds primarily alpha 1 but can also bind beta 1 it primarily causes vasoconstriction but classically
Were taught that it can also increase cardiac output there’s some newer studies showing that it does increase your cardiac output it’s clear to me based on the data whether it’s due to the fact that it possibly constricts the venous system and therefore increase your preload or possibly that in septic shock where about 20 to 30 percent of patients develop septic
Cardiomyopathy it may increase coronary perfusion pressure and therefore increase improve cardiac function therefore output it is the drug of choice for septic shock according to their society a critical care medicine guidelines it is dosed iv and the usual dose is four to twenty mics per minute but that can also be given as a bolus of four to eight in micrograms
And i’ve often seen it caused reflex bradycardia i can’t recall ever having seen a cause tachycardia guys thank you very much for watching make sure that you like subscribe and share this video like it if you like it if you don’t like it then don’t like it and then subscribe if you want more videos we upload videos regularly so if you subscribe to the channel you
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Transcribed from video
Effect of Epinephrine and Nor-Epinephrine on the Cardiovascular System By Drbeen Medical Lectures