Blood pressure- just not making sense

[squirtle]

I had trouble understanding blood pressure in term one of the nursing program, and ovbiously it is something I need to understand! Does anyone know of a good web site where I can read exactly how the heart pumps and what happens throughout the cardiac cycle and how various things affect blood pressure...

Just an example of some trouble I am having (that came up today) is that I know if a person's bp becomes too low we push fluids. I think this is because it opens up the veins, but what confused me is that if a person goes into shock (for example a pregnant woman getting an epidural) the blood rushes down to her lower extremities... if we push fluids, how does that solve the problem because wouldn't that continue to allow the blood to rush down?

I think I need to learn beginning with the basics and was hoping someone could give me a link to a tutorial or something that would help me out.

Thank you in advance!

[nclexwarrior]

Pushing fluids when a persons BP is low is because we are expanding their volume. IE..... A person comes in with cardiogenic shock we will give fluids wide open to increase thier circulating volume and probably give Dobutamine to cause an increase in Cardiac output.

Another example is a patient with anaphylactic shock. Anaphylactic shock causes the blood vessles to dialate caused by the release of histamine . Their blood pressure gets very low, we will give them fluids to increase circulating volume and also give them epinephrin to cause their blood vessles to constrict thus bringing up the blood pressure.

The pregnant women will drop her blood pressure because epidurals will cause vasodialation. Thus giving fluids will keep their blood pressure up by increasing circulating volume.

[TakeTwoAspirin, MSN, RN, APRN]

Try this website: http://library.med.utah.edu/kw/pharm/hyper_heart1.html

Also, whatever text book you have, look and see if there is a CD that comes with it and check to see if they have any annimations of the cardiac cycle on there.