Negative CVP?

[RN92]

Im an old nurse (14yrs), but new to ICU. Hoping someone can answer a question for me. What does it mean or what can it mean when your cvp number goes negative? I know the transducer has to be level with the heart. The number was positive all day and all of a sudden goes negative. Checked the equipment, pressure bag, etc..found no mechanical reasons. Asked my preceptor. He said that if Ive checked everything, then thats all I can do. HUH?

Is there any "medical" reason why it would go negative? If not, why dont the monitors stop at zero? I cant handle just saying, "oh well,just wait and see if it fixes itself". Im the type of person that has to know why this is or is not important to know/remember.

[Zookeeper3]

how do you determine the CVP yourself? Our monitor shows a crappy wave form and a number, that's it. By the way, how should the CVP waveform actually look?

When the patient is positioned per policy either at 30 degrees up of flat, and the transducer is leveled and zeroed, print a strip of respirations and the cvp, at end expiration, look at your scale, which should be in optimal mode, or conducive to the #'s and manually look at the scale on the strip and "see" the CVP number then.

there is much more to reading the waves, but this is a basic start, all pathology of the patients heart aside. Master this, then read a critical care book about what the bumps or waves really mean. Going into cannon waves and what not will not help you at this initial point with your question, but there is much more to learn to get accurate readings.

Great question!

[Indy, LPN, LVN]

Isn't it also possible to just watch the patient breathe, and, at end expiration, glance at the monitor? The number changes all the time...

[christen13]

It is not possible to have a true negative CVP!! You will see a negative reading on the monitor, but that is not the actual cvp....unless you have a MAJOR problem. Negative pressure in the vein....not good. Check the line, look at the waveform, look at the patient, positioning can change the reading.....but it is NOT negative. Do not chart a negative cvp!! Think about it .... all shift you are saying the patient has negative pressure!!! Ouch, you didn't do something about this???? What it may and usually does indicate is that the cvp is low and they are dry.....but not that dry :)