Hyponatremia causes

[Mommy_of_3_in_AL..RN]

Had a patient admitted to me today, 80 yof..history of SIADH. Sodium in the AM was 114, and was 118 on admission when i drew it. We were ordered to have a CVL placed, which we did, and start 3% saline at 10 cc/hr. Patient had q 1 hour serum sodium checks. Drew sodium from CVL after placement confirmed, before starting saline. saline was started while awaiting results. Came back at 127. Physician was there, and ordered D5W at 30 cc an hour, and stop saline. Redraw in an hour. Drew sodium before starting D5, and right after ending saline. Resulted back at 116...my question is, what do you think could cause such a yo yo sodium level (other than lab error, which we are leaning toward). When i left, they were still awaiting the latest levels. All fluids have been stopped, with orders to continue q 1 hour checks, and call physician with every result (which i know is important, but it seems like we did nothing but draw blood all day..as soon as we would get a result and call her, get a new order, we were drawing another level, only to have to get another order). I would just like to be able to offer some suggestions or insight that maybe we arent seeing. Thanks guys!!

[criticalHP, MSN, RN]

I question the accuracy of the 127 sodium result. 3% saline at 10ml/hr is not going to bring NA+ from 114 to 127 in one, two or three hrs...

[Mommy_of_3_in_AL..RN]

I agree...and when i went in yesterday, i went back over the night labs, and we wre right. The 127 was a lab error obviously..all the other night labs were 114-116 consistantly, eve after8 hours of 3% saline.

[moonshadeau, ADN, BSN, MSN, RN, APN, NP, CNS]

Where was the blood drawn from? Arterial line, Central line or peripheral? If it was drawn centrally, then that seems like a logical possiblity that it was a technique error, perhaps from the line being inadequately flushed prior to drawing the sample?

[Mommy_of_3_in_AL..RN]

Had the blood been drawn from the old line, then i would have thought that as well. However, the blood was drawn from a newly inserted central line, by the MD on insertion. No fluids had yet been run into that line at all. In fact, the higer level and lower level were both drawn from there, before fluids were started, which is what, in combination with the following 8 low levels, led us to a lab error