CVP & PEEP Relationship - help!

[Fluidified]

I am having trouble understanding the relationship between PEEP and CVP. When you increase PEEP on a vent, does CVP increase or decrease? And if you could, please explain the physics/physiological mechanism behind why this happens.

THANK YOU.

[JeanOfAllTraits]

I'm gonna talk this one out loud with ya. Then we'll let the experts pop in. :)

PEEP=positive end expiration pressure. When the PEEP is increased, more pressure would stay in the lungs to assist in in keeping the alvioli and bronchioles open.

CVP= Central venous pressure. We measure it at end expiration as that is when the pressure in the lungs is lowest. When there is more pressure is the lungs, there is more pressure on the vessles.

So, put it all together. The PEEP is raised, pressure in the lungs is higher. Therefore the pressure on the vessles is higher. Therefore tour CVP is higher with an increase in PEEP.

However, I could be confused on the pathophysiology in general....so I leave the door open to all the wise and experienced crical care nurses on here. :)

[Biffbradford]

That PEEP can also decrease the venous return to the heart and drop your blood pressure. Ergo: BP in the toilet? Turn off PEEP!

[mcubed45]

The main takeaway is that if your patient's on a lot of peep, your CVP reading is artificially elevated. You need to keep that in mind if you're using your CVP to guide fluid resuscitation. They may still be dry even with a high CVP reading.

[clarkheart]

I've been told by Intensivists that any PEEP over 5 will artificially give CVP readings on a one to one ratio. Example--PEEP of 8 will artificially raise the CVP 3 points. I've always been told to keep that in mind when accessing volume requirements.