We try to treat pt by addressing the underlying cause, not the symptoms or the #'s per se. While bradycardia could be caused by shock, bradycardiac could also be caused by the heart itself not pumping out enough blood due to too much betablockers or the pacemaker is not working. Therefore, you may not want to give Dopamine or NorEpi which will cause severe vasoconstriction. You can just use atropine
Showing posts with label special topics. Show all posts
Showing posts with label special topics. Show all posts
Septic shock?
Normally, in normal physiology, when one part of your body is infected, that part will have vasodilation with increased release of cytokines, white blood cells.
Now, in pathophysiology, in sepsis, when the entire body has vasodilation due to whole-body infection, it's getting worse. Important internal organs such as the brain, the heart, the kidneys don't have enough blood perfusion. Vasodilation is everywhere including the peripheral digitals.
Therefore, you want to use vasopressors to return blood to these important organs.
Now, Phenyl-ephrine is very strong, it can cause gangrene in peripheral digits leading to ultimate amputation. So, you don't want to use Phenylephrine as the first-choice drug.
At the early stage of sepsis, the heart beats very fast to compensate and pump blood to all of these dilated blood vessels throughout the body. You can just give IV hydration to these patients to help them out (pioneered by Blalock from Johns Hopkins). Sometimes you'll have to give like 3-6L of NS (in total) free standing to these patients. The patient will have blood pressure and heart rate going towards more normal limits as they receive 1-3L NS free standing. However, these fluids will go to the insterstitial space or extravascular to the peripheral causing edema. As the edema develops, the patient will refract back to near-septic shock and blood pressure will go low and heart rate will increase again. Then, you'll treat them with more NS for their fluids (aggressive fluid hydration) together with IV antibiotics. If patient becomes stabilized, they are good. If not, you'll start them on vasopressors. Now, the choice of vasopressors would be NorEpi since it doesn't cause arrhythmia as much as Dopamine (tho some said DOPamine is the choice for good perfusion of kidneys due to dopaminergic agonist effects). Phenylephrine will be the drug of choice tho if heart rate is too high.
Now, remember that Phenylephrine is not the drug of choice for first line because you want some increased heart rate (Beta 1 agonist effects) and some heart contractility (alpha 1 effects) => Alpha 1 (NorEpi)
Dopamine or NorEpi.
Most ICU Dopamine - more arrhythmia
Pulm ICU & Cardio ICU - NorEpi first choice, preferred
Phenylephrine - vasoconstrictor only, better to have iotropes or chronottropes.
However, if the heart runs too fast, Dopamine, NorEpi are out for Phenylephrine to be used.
~with help from my bf
~Wonder Me!
Normally, in normal physiology, when one part of your body is infected, that part will have vasodilation with increased release of cytokines, white blood cells.
Now, in pathophysiology, in sepsis, when the entire body has vasodilation due to whole-body infection, it's getting worse. Important internal organs such as the brain, the heart, the kidneys don't have enough blood perfusion. Vasodilation is everywhere including the peripheral digitals.
Therefore, you want to use vasopressors to return blood to these important organs.
Now, Phenyl-ephrine is very strong, it can cause gangrene in peripheral digits leading to ultimate amputation. So, you don't want to use Phenylephrine as the first-choice drug.
At the early stage of sepsis, the heart beats very fast to compensate and pump blood to all of these dilated blood vessels throughout the body. You can just give IV hydration to these patients to help them out (pioneered by Blalock from Johns Hopkins). Sometimes you'll have to give like 3-6L of NS (in total) free standing to these patients. The patient will have blood pressure and heart rate going towards more normal limits as they receive 1-3L NS free standing. However, these fluids will go to the insterstitial space or extravascular to the peripheral causing edema. As the edema develops, the patient will refract back to near-septic shock and blood pressure will go low and heart rate will increase again. Then, you'll treat them with more NS for their fluids (aggressive fluid hydration) together with IV antibiotics. If patient becomes stabilized, they are good. If not, you'll start them on vasopressors. Now, the choice of vasopressors would be NorEpi since it doesn't cause arrhythmia as much as Dopamine (tho some said DOPamine is the choice for good perfusion of kidneys due to dopaminergic agonist effects). Phenylephrine will be the drug of choice tho if heart rate is too high.
Now, remember that Phenylephrine is not the drug of choice for first line because you want some increased heart rate (Beta 1 agonist effects) and some heart contractility (alpha 1 effects) => Alpha 1 (NorEpi)
Dopamine or NorEpi.
Most ICU Dopamine - more arrhythmia
Pulm ICU & Cardio ICU - NorEpi first choice, preferred
Phenylephrine - vasoconstrictor only, better to have iotropes or chronottropes.
However, if the heart runs too fast, Dopamine, NorEpi are out for Phenylephrine to be used.
~with help from my bf
~Wonder Me!
Why it works?
We use DOBUTamine for heart failure because DOBUTamine only increases the heart muscle contractility (inotropic) but not the peripheral blood vessels (too little alpha 1 effects to have any effects).
In heart failure, the heart itself has already failed to contract due to myopathy. Using DOBUTamine would increase the heart's inotropic effects without vasoconstriction causing increased peripheral blood vessel increase.
If you use DOPamine, you can cause inotropic (b1 agonist) and increased peripheral pressure due to vasoconstriction (a1 agonist). The a1 agonist effect will cause increased blood pressure forcing the heart to work even harder. This is not good for an already weak heart (heart failure). Therefore, DOBUTamine is preferable.
Now, if you have a shock case in which the heart beats too slowly and the blood pressure is too low but the total blood volume is not lost, you can use DOPamine to increase heart rate (beta1 effects) and vasoconstriction (alpha 1 effects). And, theoretically, DOPamine is preferred over other vasopressors for shock because it perfuses the renal functions thru the dopaminergic receptors (DA receptor).
(thanks to my bf for explaining this to me :))
~Wonder Me!
We use DOBUTamine for heart failure because DOBUTamine only increases the heart muscle contractility (inotropic) but not the peripheral blood vessels (too little alpha 1 effects to have any effects).
In heart failure, the heart itself has already failed to contract due to myopathy. Using DOBUTamine would increase the heart's inotropic effects without vasoconstriction causing increased peripheral blood vessel increase.
If you use DOPamine, you can cause inotropic (b1 agonist) and increased peripheral pressure due to vasoconstriction (a1 agonist). The a1 agonist effect will cause increased blood pressure forcing the heart to work even harder. This is not good for an already weak heart (heart failure). Therefore, DOBUTamine is preferable.
Now, if you have a shock case in which the heart beats too slowly and the blood pressure is too low but the total blood volume is not lost, you can use DOPamine to increase heart rate (beta1 effects) and vasoconstriction (alpha 1 effects). And, theoretically, DOPamine is preferred over other vasopressors for shock because it perfuses the renal functions thru the dopaminergic receptors (DA receptor).
(thanks to my bf for explaining this to me :))
~Wonder Me!
