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Shock | Hypovolemic, Septic, Cardiogenic | What are the signs and symptoms of shock?

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What is shock?  If someone ever tells you it is “low blood pressure” . . . you need to correct them.  This podcast provides a brief overview of three types of shock, their cause, and clinical signs.  You can check out our lessons on shock HERE!

What clinical signs will you see with septic shock, how do they differ from those you will see with hypovolemic and cardiogenic?  Why will the patient have a high temp with septic shock and a low temp with hypovolemic?

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Podcast Transcription

Welcome to the podcast, the podcast created by nurses for nurses. Are you ready to take your learning to the next level? Sit back and crank up the volume. Here’s your host, Jon Haws.


This is Jon with Today, we’re going to do just an incredibly brief overview of shock, what shock is, and some of the main types of shock and what is affected in that type of shock and what exactly is going wrong with the system in order to cause that type of shock. We have a 3-page handout with this with some diagrams and some graphs and things and that’s available at That’s You can get the PDF download. It’s free to use, free to distribute, whatever you want to do with it, but it will basically outline what we talked about here with some different graphs and diagrams and everything.


Again, this is going to be just a very brief overview just to give you a quick understanding of what shock is. First of all, to understand what shock is, we need to understand what the main goal of the cardiopulmonary system is. The whole entire goal of the heart and lungs is essentially to deliver oxygen to the body, to the tissues to make sure that they’re receiving the oxygen they need to carry out their metabolic processes. Our heart pumps blood to the lungs where that blood receives oxygen and gets rid of CO2 and then it goes back to the heart and from there, the heart pumps that blood throughout the body. The whole goal of that is to oxygenate the body.


Now shock is a state of the vital organs not receiving enough oxygen. Shock is not low blood pressure. If someone teaches you that shock is low blood pressure, something you need to … Just give them a kind correction and tell them that shock is actually a state of the body not receiving … The vital organs not receiving the oxygen that they need. There’s 3 types of shock that we’re going to discuss briefly today and that’s going to be hypovolemic, cardiogenic, and septic. There’s other types of shock but we’re going to talk about those 3, hypovolemic, cardiogenic, and septic.


Essentially with hypovolemic shock, what we’re dealing with is low volume. Some sort of insult has happened to the body to cause a low volume state within the body. With cardiogenic shock, we’re dealing with a broken pump. Essentially the heart is not functioning as it should and that pump is broken and so we’re not getting that oxygen distributed the way we should. With septic shock, we’re dealing with an immune response that interferes with vascular tone. Some sort of infectious process or something happens within the body that causes this immune response that is so severe that it interferes with the vascular tone within the body.


First of all, we need to understand the oxygen delivery system and to understand that, it’ll help if you go and download this diagram that I have illustrated up there at the Basically what we have is in the center of it all, we have the heart. From the heart, blood goes out from the heart to the non-vital organs and to the vital organs. Then from there, it goes back into the system and in our reserve, our vessels, and back into the heart. Blood comes from the heart, the vital organs, and to the non-vital organs. Then from there, it’s collected back and returns to the heart.


With each type of shock, something different is affected that alters our oxygen delivery system. As we talked about with hypovolemic shock that the term itself tells you what’s going on. It’s hypovolemic state. The initial insult is low blood volume. For whatever reason, injury, gunshot wound, whatever, hemorrhage after surgery, something like that, we have a low blood volume state within our body. Those vessels leading to the heart have less blood volume in there. What’s going to happen with that is we’re going to have a decreased preload or essentially a decreased CVP.


Since there’s less blood returning to the heart, they were also going to have a decreased cardiac output. There’s less blood coming back to the heart and because of that, less blood is going to be able to go out to the heart. To compensate for that, what we have is we have an increased heart rate and our blood pressure is going to be a little bit decreased as well because of that decreased cardiac output, so heart rate’s going to go up to try to compensate for that. Then our systemic vascular resistance so the vessels on the other side of the heart, as the blood’s coming out, are going to squeeze to try to compensate for that low volume.


Then what’s going to also happen is blood is going to be shunted away from our non-vital organs to help profuse our vital organs. What that means is, so one of our non-vital organs for example is going to be our skin. What’s going to happen is blood is going to be shunted away from those non-vital organs to help profuse the vital organs. For that reason with hypovolemic shock, you’re going to see a decreased temp and you’re going to see that decreased preload, increased systemic vascular resistance, the increased heart rate, decreased cardiac output, and decreased blood pressure.


There are several stages of hypovolemic shock and we rate this in classes, class 1 through 4, and that is all determined on the amount of blood loss. If you have an estimated blood loss of between 500 to 750 mLs, then that’s class 1. 750 to 1,500 is class 2. Class 3 is 1,500 to 2,000 mLs of blood loss. Then in class 4, hypovolemic shock is going to be anything greater than 2,000 mLs of blood loss. That’s how you can do that. 500 to 750, 750 to 1,500, 1,500 to 2,000, and over 2,000 is class 4. That’s the basics of hypovolemic shock.


Now with cardiogenic shock, the initial insult is a bit different. With cardiogenic shock, what’s happening is the failure of our pump. Our heart has failed. The initial insult is a decreased cardiac output. That pump isn’t working anymore, it’s not pushing blood forward so what’s going to happen is we’re going to actually have an increased preload as opposed to our decreased preload in our hypovolemic shock. Because our pump isn’t working appropriately, we’re going to have that increased preload. We’re going to have a backing up of our blood.


Again because we’re having a decreased cardiac output, we’re going to see that increased systemic vascular resistance like we did in hypovolemic shock, decreased blood pressure, and increased heart rate. Again with the cardiogenic shock, you’re going to see blood shunting away from those vital organs and you’re going to see that decreased temp again as well. With cardiogenic shock, just the pump’s broken. It’s not pushing blood forward, so initial insult is our decreased cardiac output and because of that, we’re going to have our increased preload.


With septic shock, it’s a little bit different here with septic shock. What happens with septic shock is we have this massive immune response, this inflammatory response throughout our body and that initiates a system vasodilation and so the cytokines and everything, they go and attack these vessels and it caused this vasodilation and so because of that, what’s going to happen is … Basically, what’s the initial insult here is this inflammatory, this immune response is going to go and affect these vessels, these arteries, and it’s going to cause this dramatic vasodilation and because of that, you’re going to see a decreased systemic vascular resistance. That is our initial insult with septic shock is this immune response that causes this dramatic vasodilation which leads to our decreased systemic vascular resistance.


What’s happening here is the vessels on the output side of the heart are vasodilated so dramatically that it decreases our systemic vascular resistance. What that’s going to do is it’s going to cause our heart rate and our output to try to increase, to try to make up for this so we’re going to see this early on, we’re going to see this increased cardiac output. We’re going to see this increased heart rate. We’re also going to see the decreased blood pressure though because of that massive vasodilation.


Then we also have this failure of the vessels in the heart to know where to shunt blood so the blood’s actually going to go to our non-vital organs and because blood shunts away from our vital organs into our non-vital organs, this is why with septic shock, you’re going to see increased temperatures that’s pushing blood into these non-vital organs inappropriately. For that reason, you’ll see temps of 104, 105 with the septic patients. They’re going to septic shock and because of this vasodilation, you’re actually going to see this decreased preload again.


We have this vasodilation with septic shock when we have blood shunting to our non-vital organs, so because blood’s going to the skin and things like that, we’re going to see that increased temp. Because we have this massive vasodilation coming out of the heart, we’re going to see a decreased preload, a decreased amount of blood going back into the heart. Our heart’s going to try to compensate with the increase in cardiac output and heart rate. We’re also going to see that decreased blood pressure again. That’s what septic shock is.


That’s the basic overview of hypovolemic, cardiogenic, and septic shock. Very basic overview. The important thing to remember is what the initial insult is which each of these 3 types of shock. We have a little graph, a little chart at the that outlines these hemodynamic parameters and what the initial insult is with these 3 types of shock. With hypovolemic, our initial insult is going to be that decreased preload, that decreased CVP, and that’s going to lead to the changes there. With our cardiogenic shock, our initial insult is that broken pumps or it’s going to be that decreased cardiac output. With septic shock, it’s systemic vascular resistance is decreased dramatically because of extreme vasodilation.


That’s what’s happening there. Then what’s going to happen initially with septic shock is our tissues are going to be attempting to draw in extra oxygen and so our ScvO2 initially is going to be low and then as we progress on with septic shock, the tissues become less efficient at drawing oxygen out of the blood. Our ScvO2 then is going to increase with septic shock and our tissues are going to be drawing in oxygen as they need to. That’s why ScvO2 is going to be monitored as well as CVP. It gives a physician idea of what’s actually happening within the body and how the organs are using oxygen. If they’re not effectively using oxygen, then a plan of cares need to change and things like that.


All right. That’s just a very basic overview of hypovolemic, cardiogenic, and septic shock. This is Jon with If you have any questions, please contact us at [email protected] We appreciate your honest, kind reviews on iTunes and Stitcher and if you have any questions, please contact us. Again, go to and that’s going to help give you a basic overview of what shock is and these different 3 types of shock with this 3-page PDF download of graphs and charts. All right. We appreciate you listening and have a good day.


Thank you for listening to the podcast. Visit us at for disclaimer information and to keep the learning going.