RA pressure vs CVP

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I've always heard CVP referring to RA pressures, including the research I've read. I just recently moved and when I called the RA a CVP (talking about the proximal port of a PA catheter) I was corrected and told it is an RA, NOT CVP since the reading is coming from the right atrium. The research I've read refers to the CVP when referencing this waveform, as we are actually estimating the right ventricular end diastolic pressure.

Can anyone provide any input as to the difference between RA and CVP?

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Specializes in critical care: trauma/oncology/burns.

Hello Whatnext:

Gee, I would have to agree with you.

Right atrial pressure (RAP) is measured at the proximal port of the pulmonary artery catheter (which is located in the right atrium) hense calling it the RA or RAP. Atrial pressures are commonly used to evaluate pre-load, because, as you stated, atrial pressure correlates to the end-diastolic pressure for the respective ventricle.

May I quote from Robin Donohoe Dennison Pass CCRN third edition, 2007, p.68: "Right ventricular end-diastolic pressure and preload are evaluated by right atrial pressure"

Maybe it is a case of "you say tomato and I say tomahtoe"...?

Dunno....I guess as long as it doesn't affect patient care....."when in Rome..."

Just as long as everyone agrees on the normal values of RA v. CVP.

athena

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Specializes in Cardiac.
Hello Whatnext:

Gee, I would have to agree with you.

Right atrial pressure (RAP) is measured at the proximal port of the pulmonary artery catheter (which is located in the right atrium)

Or with a central line or open ended PICC.;)

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I figured it was just a preference, or whether one is taught using RAP vs CVP. This particular nurse was adamant that it was RAP and that to call it CVP was wrong, although the values for CVP and RAP are the same. Maybe she would use CVP if the tip of a catheter (central line, etc) was not truly in the right atrium, but the vena cava (of course, the literature I've read says it is essentially the same). I just wanted to make sure there is not something I am missing (I came from a surgical trauma ICU and am now in CICU), but I did not want to go round and round arguing about such a thing with this nurse when we agreed on the normal values.

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Specializes in ICU.

UUHhmm. Yeah. Last I checked we are 'measuring' the same value although we love to refer to it as RA or CVP.

I'd love to see where the difference is, if there is any, and what are the clinical applications for the minute difference.

We seem to be splitting hairs here.

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Same thing -

tell the RN to check out pacep.org (Swan education project) since she's so sure CVP doesnt equal RAP

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Specializes in CTICU.

RA = CVP. Call it whichever pops your cork.

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Specializes in ICU, Education.

I think that was just someone splitting hairs (maybe trying to make themselve's look better by making you look bad??). CVP can either be from the SVC or the RA. the number is the same.

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I have heard that the proximal port of the swan actually sits just inside or just outside the ra, I agree splitting hairs. the RA is not that big the number still indicates the same thing no matter what you want to call it. I agree with dorimer

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Specializes in Dialysis.

Before there were monitors that would give a digital display you used a glass tube connected inline to the venous catheter. A CVP manometer would measure in centimeters how high the water in the tube would be above the right atrium. With the advent of monitors with transducers this is no longer used. The problem is CVP measures with water and monitors are measuring with millimeters of mercury so 1.34 cms of water equals 1 mm of mercury.

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Specializes in critical care: trauma/oncology/burns.
Before there were monitors that would give a digital display you used a glass tube connected inline to the venous catheter. A CVP manometer would measure in centimeters how high the water in the tube would be above the right atrium. With the advent of monitors with transducers this is no longer used. The problem is CVP measures with water and monitors are measuring with millimeters of mercury so 1.34 cms of water equals 1 mm of mercury.

Chisca:

Oh my goodness, I thought I was the only one that remembered that! Remember calculating the CVP measurments? So I guess you should remember glass syringes and remember the "drum catherter" usually inserted in the brachial? Or when arterial transducers first came about, nothing was disposible, used metal transducers and you had to put a drop of saline on the membrane...or how about how you had to check for the barometric pressure before analyzing an ABG? Or glass bottle system for chest tubes?

Ahhh the "good" ol' days, so glad they are gone! (Well, sometimes....)

athena

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I was always taught that the RA MEAN = CVP. The RA pressure has a systolic and diastolic waveform just like any other hemodynamic measure. Do some running totals next time you have a Swan. Write down your RA mean and see if it doesn't correlate with the CVP. Your PA diastolic should also correlate with your PA wedge pressure.

Just my :twocents:

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