eGFR and iodine doses

DutchgirlRN, ASN, RN · Jan 4, 2008

Sorry, but I'm running out of people to ask this question.
I'm a CT Technologist for an imaging center in northern Virginia. I've been doing CT for about 8 years now, and as far as renal function, I've always used the Creatinine level as a standard (i.e. if it's over 1.5, no contrast).
There seems to be some sort of discussion about GFR. I work at another imaging center, and the nurses there start the IV's, and screen the patients. When they bring me the patient to scan, they've already figured out the GFR, and have noted how much contrast I am able to give this patient.
I've found the online calculators for obtaining the GFR, but I can't figure out how to determine how much contrast to give.
Sorry, I've been told that I'm very anal retentive.
papa

Anal retentive is not a bad thing when you have your patients welfare at mind. I commend you for being anal!

Our protocol is if the GFR is over 60 then no contrast period without prior hydration of 250cc NS minimum an additional 250cc NS post CT. Mucomyst prior to scan and 12 and 24 hours post scan. We no longer go by the creatinine except to use it in calculating the GFR. BUN has gone totally by the wayside. For GFR's under 60 contrast as usual.

If a patient has one kidney or known renal disease we cannot contrast without an order from a Nephrologist.

papaRTRCT · Jan 4, 2008

yeah, i've gotten that far. but somewhere in this wonderful world is a formula or something, that will tell how much contrast to give (with or without pre and post hydration). i'm prety sure it's related to GFR.

:banghead: :selfbonk:

papa

Editorial Team / Admin · Jan 4, 2008

Errrrr, Dutch, don't you mean if the eGFR is BELOW 60, no contrast is given???

And, if it's ABOVE 60 (meaning the kidneys are functioning well, i.e., have a higher filtration rate) then contrast may be given?

I've never heard of any formula, based on the eGFR, by which one determines the amount of contrast to be given.

I just did an online search (not exhaustive ) and found no formulas.

I did find the following useful links to articles dealing with CIN prevention and treatment:

http://www.medicalimagingmag.com/issues/articles/2007-05_CIN.asp

http://ndt.oxfordjournals.org/cgi/content/full/22/7/1812

http://www.imagingeconomics.com/issues/articles/2007-05_11.asp

In general, the Cardiologists and Radiologists I've worked with go by the pt's weight: goal is to give ml of contrast below the wt (in lb, e.g.: goal is no more than 150ml of contrast for a 150# person, or, 2X the wt in kg: no more than 150ml contrast for a 75kg person).

There are times when the benefit of giving more outweighs the risk of CIN. This is a clinical decision, to be made by the MDs.

papaRTRCT, I'd be interested to see the formula the nurses of which you speak are using, and where they obtained it (evidence-based!), for my own edification.

BTW, kudos to you for searching out evidence-based guidelines/practices.

Have worked with many excellent techs through the years, worth their weight in gold! It's a team thing! :)

DutchgirlRN, ASN, RN · Jan 4, 2008

Errrrr, Dutch, don't you mean if the eGFR is BELOW 60, no contrast is given???
And, if it's ABOVE 60 (meaning the kidneys are functioning well, i.e., have a higher filtration rate) then contrast may be given?

:brnfrt: Yes, Yes! Thanks for straightening me out. I've been out too long and been so sick I had a huge brain fart. Thanks so much for catching that.

I've never heard of any formula, based on the eGFR, by which one determines the amount of contrast to be given.

Nor have I. When the GFR is between 50-60 sometimes we ask the radiologist what he wants us to do, as long as the patient is not a diabetic or has known renal disease and the CT is really essential to the patient. 90% of the time he says go ahead but use half the usual contrast.

I'm hearing down the pipeline that these GFR protocols will become progressively more selective and defined.

DutchgirlRN, ASN, RN · Jan 4, 2008

yeah, i've gotten that far. but somewhere in this wonderful world is a formula or something, that will tell how much contrast to give (with or without pre and post hydration). i'm prety sure it's related to GFR.papa

Papa, I'd go to the top of your department and ask for the information that you need. When in doubt as to how much contrast to give, ask the radiologist, write down a written order for the chart and follow that order.