Swan Ganz

Specialties MICU

Published

I have a question: With a swan, when obtaining a CVP reading, you turn the stop cocks up and down ( left up, right down).. Why do we move the stopcocks? I guess I'm just looking for the rationale behind this..OR maybe I'm just over thinking it..

Specializes in Medical/Telemetry. Now ICU.

Never used a Swan. Sorry can't help. Plus I'm just new to the ICU...2 months.lol

I'm a pretty new nurse as well, but this is how I recall learning how to do this (someone correct me if I'm wrong)....The stopcock should be turned off to the injectate syringe if you want to get the CVP. The injectate syringe (at least here) is connected in a straight line to the Swan port and the CVP line is connected perpendicular to these. So if you want to get a CO you turn the stopcock toward or "off" to the perpendicular tube (the CVP) to close off that connection and allow the saline from the injectate to run through. When you are done turn the stopcock toward the injectate syringe to open back up the CVP line and resume CVP monitoring. The reason you want the stopcock open to the CVP line when monitoring CVP is because the transducer senses the pressure as its transmitted through the saline in the CVP line and translates this into the number readings you see on the monitor. That's why things like air bubbles and kinks in this tubing can distort the accuracy.

I hope this doesn't sound confusing, but this is how I understand it to work.

It depends on which catheter you're using. You need to ask somebody you work with.

Specializes in ER/ICU/STICU.

I agree it depends on the swan. For instance we use a swan the measures CO continuously so there is no injectate.

Remember the Swan is just a line. You will have various ports on the line that will give you different values dependent on the pressures at that end, for example you PAP is in the pulmonary artery the distal port (usually labeled yellow). CVP should be in the right atrium (most likely colored blue) and a white port for infusions. I am not sure what stop cock you are referring to. The one on the transducer we use for zeroing the line. NOW...if you are infusing through the CVP port, which is not wrong, but not best practice (I never do it). You need to turn off the infusing fluid with the stopcock, zero your line, and then get an accurate reading. Remember as long as you infuse through it you will not have an accurate reading.

NOW...if you are infusing through the CVP port, which is not wrong, but not best practice (I never do it).

:confused: Why do you say this?

Because you want to have an accurate reading continuously. This is especially important with valve replacements as they tend to require more fluid. You always want as clear of a picture as possible at all times.

I have a question: With a swan, when obtaining a CVP reading, you turn the stop cocks up and down ( left up, right down).. Why do we move the stopcocks? I guess I'm just looking for the rationale behind this..OR maybe I'm just over thinking it..

Because if you don't then you're not opening the path to the transducer and you can't get a reading unless the path from the particular port is open to the transducer. It's like completing a circuit.

When you move the stopcock you interrupt one "circuit" to complete another. It's just a function of a multi-port stop-cocked system---not really a big deal if you think of it logically. Basically just a plumbing issue.

I suggest that you go over the construction and function of the PA cath to really get an understanding of how it works. Once you grasp that I'm sure everything will fall into place for you.

I've never heard the rationale for not infusing through the CVP port and frankly, we do it all the time---you obviously have to have the IVF turned off at the time of the CVP reading and for zeroing the transducer to complete the transducer "circuit" so I'm confused as to why that would even be an issue. We also use a CCO machine (Vigilance) and occasionally still do bolus CO's.

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