Question about maintaining Blood pressure

This forum made possible through the generous support of SDN members, donors, and sponsors. Thank you.

MedStudent219

Full Member
2+ Year Member
Joined
Jul 3, 2018
Messages
57
Reaction score
19
so this is going to be a really dumb question but im just a bit confused,

from what i understand, a patient with very low blood pressure, its important to try and maintain that blood pressure by giving drugs that cause vasoconstriction (which logically increases bp). However doesnt vasoconstriction decrease the blood flow? why would we want to do that? im just really confused, sorry if that doesnt make sense. any help is appreciated! :D

Members don't see this ad.
 
Your posting history is weird. This post is strange. You’ve said you’re an M2 but this is such a basic concept that I think you’re a troll!

How do I answer questions about cases such as "A 26 year old male was brought in etc etc what diagnosis is this". I honestly have no clue, I have a good understanding of the basic clinical sciences but I'm not sure how to put it together to understand symptoms. Any resources recommended? Thanks! :)
Hi, sorry if this is a dumb question. When we've been taught cardiovascular examinations, we've been taught to palpate so and so intercostal space to find each valve and then auscultate from there. That sounds slow and I was just wondering, I've never actually seen a doctor do that. They usually just auscultate and know where the valves and whatnot are. So out of curiosity, how does a doctor know where to ausculate (i.e. the positioning of the valves?0 Is it just based off surface anat (I was wondering, if this is the case, would this always be possible in patients if there are pathologies that change the relative position of valves?). Once again, sorry if this is dumb. I'm just a bit confused and would love to be enlightened. Thank you so much! :D
I'll be starting on OB GYN :)
 
The vasoconstricting drugs increases vasoconstriction only to certain places, like the extremities and the gut. Other vital organs like the brain, kidneys, etc. receive increased flow. That’s why patients on pressors can get ischemic necrosis of their extremities.
 
Members don't see this ad :)
Your posting history is weird. This post is strange. You’ve said you’re an M2 but this is such a basic concept that I think you’re a troll!
Oh my, I must be the king of trolls by asking a question about something I hadn’t looked at in ages and was confused about. I spent an hour looking at it and was just confused, all of us have days where we might not understand something that we notmally would. Rather than giving someone a hard time, just ignore the post.
 
  • Like
Reactions: 2 users
The vasoconstricting drugs increases vasoconstriction only to certain places, like the extremities and the gut. Other vital organs like the brain, kidneys, etc. receive increased flow. That’s why patients on pressors can get ischemic necrosis of their extremities.
Thanks so much! :D that makes perfect sense :) happy holidays!
 
The vasoconstricting drugs increases vasoconstriction only to certain places, like the extremities and the gut. Other vital organs like the brain, kidneys, etc. receive increased flow. That’s why patients on pressors can get ischemic necrosis of their extremities.

I had a very young surgical patient during m3 that had ischemic necrosis 2/2 pressors and had to have both hands amputated and bilateral BKAs. Very sad case.
 
  • Like
Reactions: 1 users
Oh my, I must be the king of trolls by asking a question about something I hadn’t looked at in ages and was confused about. I spent an hour looking at it and was just confused, all of us have days where we might not understand something that we notmally would. Rather than giving someone a hard time, just ignore the post.

I apologise. ‘Twas unnecessary on my part.
Glad the posters after me were able to give more useful information.
 
If their BPs are soft, you figure out why. You don't always go to pressors. In fact, you should always think about fluid resuscitation first. Get large bore IVs in and bolus fluids. A good framework to think about this goes back to physiology. What determines BP? The good old Ohm's Law. P = CO x R. CO = SV x HR. So there are three things that can affect pressure - stroke volume, heart rate, and resistance. Decreases in each of these can drop your blood pressures.

A useful framework is to think about causes of shock. Because that's why you want to treat soft BPs in the first place. If your BPs go too low, your organs aren't perfused and you go into shock. There are four big categories of shock, namely hypovolemic, distributive, cardiogenic, and obstructive.

In hypovolemic shock, you have too little circulating volume. Thus, your SV will drop. HR will rise to compensate but you can only get tachy to so much before your heart doesn't have time to fill completely. This results in decreasing BPs. In distributive shock, your vessels massively vasodilate, resulting in your resistance plummeting. This also drops your BP drastically. Your HR will respond and you will become tachy (exception is neurogenic shock, in which case the problem is a failure of sympathetic regulation so you get an inappropriate bradycardia). In both of these cases, you should start by bolusing them with fluids. If they're in hypovolemic shock, this (almost) treats the etiology. It should fix the problem unless they're actively bleeding or still losing fluids. If they're in distributive shock, you also treat the cause. In sepsis, that involves treating the infection. In anaphylaxis, you reverse the anaphylaxis. In cases of distributive shock, you think about pressor therapy if they're not responding or inadequately responding to the fluids.

The other two types of shock are different in that there's nothing wrong with your volume status or vascular resistance. The problem is in (or near) the heart. Cardiogenic shock is exactly as it sounds. Your heart is failing to do its job for whatever reason and the forward flow of blood out of the heart is impaired. Here, you do fluid resuscitation and then you give inotropes to help your heart pump. Finally, obstructive shock is when there is a physical obstruction to forward blood flow. One example is tamponade. There is an obstruction of blood filling in the heart. The definitive treatment for obstructive shock is the relieve the obstruction, e.g. pericardiocentesis.

UptoDate has a great algorithm for initial and continued management of shock.
 
  • Like
Reactions: 1 user
I had a very young surgical patient during m3 that had ischemic necrosis 2/2 pressors and had to have both hands amputated and bilateral BKAs. Very sad case.
That's awful :(

I apologise. ‘Twas unnecessary on my part.
Glad the posters after me were able to give more useful information.
That's okay mate haha! Hope your Christmas/holidays went well :)

If their BPs are soft, you figure out why. You don't always go to pressors. In fact, you should always think about fluid resuscitation first. Get large bore IVs in and bolus fluids. A good framework to think about this goes back to physiology. What determines BP? The good old Ohm's Law. P = CO x R. CO = SV x HR. So there are three things that can affect pressure - stroke volume, heart rate, and resistance. Decreases in each of these can drop your blood pressures.

A useful framework is to think about causes of shock. Because that's why you want to treat soft BPs in the first place. If your BPs go too low, your organs aren't perfused and you go into shock. There are four big categories of shock, namely hypovolemic, distributive, cardiogenic, and obstructive.

In hypovolemic shock, you have too little circulating volume. Thus, your SV will drop. HR will rise to compensate but you can only get tachy to so much before your heart doesn't have time to fill completely. This results in decreasing BPs. In distributive shock, your vessels massively vasodilate, resulting in your resistance plummeting. This also drops your BP drastically. Your HR will respond and you will become tachy (exception is neurogenic shock, in which case the problem is a failure of sympathetic regulation so you get an inappropriate bradycardia). In both of these cases, you should start by bolusing them with fluids. If they're in hypovolemic shock, this (almost) treats the etiology. It should fix the problem unless they're actively bleeding or still losing fluids. If they're in distributive shock, you also treat the cause. In sepsis, that involves treating the infection. In anaphylaxis, you reverse the anaphylaxis. In cases of distributive shock, you think about pressor therapy if they're not responding or inadequately responding to the fluids.

The other two types of shock are different in that there's nothing wrong with your volume status or vascular resistance. The problem is in (or near) the heart. Cardiogenic shock is exactly as it sounds. Your heart is failing to do its job for whatever reason and the forward flow of blood out of the heart is impaired. Here, you do fluid resuscitation and then you give inotropes to help your heart pump. Finally, obstructive shock is when there is a physical obstruction to forward blood flow. One example is tamponade. There is an obstruction of blood filling in the heart. The definitive treatment for obstructive shock is the relieve the obstruction, e.g. pericardiocentesis.

UptoDate has a great algorithm for initial and continued management of shock.
Thank you that was very informative! :)
 
Top