Wonder Me!
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!
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