This is a plea to the world, please talk to me like i am 5 years old with this!!

No, but thanks for reminding me I'm supposed to be studying for my ACLS class, LOLOL.

Preload is the pressure that fills the ventricles during diastole. This makes sense. Consider "pre" and "after" to refer to the pumping action of the heart. So preload is the pressure the heart experiences "Before pumping". In other words, while the heart is at rest or diastole. The pressure that the heart experiences as a part of preload comes from the venous system (basically, it is like the venous system dumping too much blood into the left ventricle making it so that the ventricle is too "full" and the heart needs to work harder to pump it out. Sort of like those times when you are drinking water and you just get too much in your mouth and now swallowing becomes harder.)

Afterload is the pressure that happens after the pumping action. In other words, it is the pressure the heart works against to get the blood out into the system. One way to try and remember it is afterload is caused by arteries.

Cardiac output and Cardiac Index are both formulas, CI relates to CO.

Heart rate x Stroke volume = Cardiac output. Cardiac output is the amount of blood ejected from the heart each MINUTE. Stroke volume refers to amount of blood that is ejected from the heart with each PUMP OF THE HEART. Therefore, the pressure the heart works against (preload and afterload) affect the stroke volume and thereby the cardiac output over all. And the heart rate also will adjust cardiac output over all.

Cardiac Index is a relationship between the cardiac output and the size of the patient. Basically Cardiac Index = Cardiac output divided by Body surface area. I have never calculated this though and I have never really needed to or been asked to. The one thing I remember though is that The normal range of cardiac index is 2.6 - 4.2 L/min per square meter.

The only real advice I can give is that if you understand what the heart does and what pressures might adversly impact the heart in different ways, then it will sort of "click" that the pressure can be before or after the heart is pumping and that these pressures make the heart work harder so it is less effective and stroke volume will go down. If stroke volume goes down, cardiac output goes down. If cardiac output goes down, then cardiac index goes down. And the end result is that the tissues in the body are not getting the blood supply they need.

thanks for those brilliant links, particularly like the FAQ one, that is speaking my language....simple simple simple!

thanks for those brilliant links, particularly like the FAQ one, that is speaking my language....simple simple simple!

I am glad that someone here was able to help you. Now my advice to you is to teach that information to someone else. A sibling, a friend, a parent, anyone. Because the best way to really understand something it so teach it to someone else. Or Hey, you can post what you learn on here and teach all of us!

Ok so:

you need 3 things to make a BP,

pump

volume

squeeze

CO=Pump

CVP=volume

SVRI=squeeze.

3 types of hypotension:

1)Cardiogenic=pump failure= CO goes down, svri goes up

2) Hypovolaemic=No volume so Co down, Pawp down &svri up

3)Septic=BP down, HR up, & svri down.

I found the book Hemodynamic Monitoring Made Incredibly Visual to be very helpful in learning and understanding these concepts. Good luck, you will learn these concepts.