The question was asked a while about setting aside wasted blood for the blood draws and then retruning it, Lynn responded:
 "You are absolutely correct. Return of waste blood from a syringe that has been disconnected and set aside during the remainder of the procedure is dangerous. Studies have shown that you are returning clots. A literature search will show a review article by Ann Marie Frey in JIN in 2003. Sorry but I could not copy from my database and paste into this message. Lynn"
My question is: What about using a stopcock and 2 syringes- the wasted blood would never be "disconnected", or are we still concerned about returning clots?
 Thanks.
You could still be returning clots if that syringe holding the withdrawn blood has not been heparinized. I would prefer to never return blood like this. You can however, use the mixing method for blood sampling.
Attach a saline filled syringe and flush. Leave syringe attached and withdraw 6-8 mL of blood into this syringe and then flush it back in. Repeat this aspiration and flushing procedure for a total of 4 times without disconnecting the syringe. Then detach this syringe and attach another empty syringe to aspirate the sample to be sent to the lab. Then flush the catheter as you normal would after withdrawing a sample. This method avoids the issue of discarding blood and reinfusing the waste blood.
If you do use the stopcock and 2 syringes, never leave this stopcock attached to the system as these devices are known to have a high rate of contamination and subsequent bloodstream infection. So it would be best to remove it after each blood draw.
Lynn Hadaway, M.Ed., RN, BC, CRNI
www.hadawayassociates.com
Lynn Hadaway, M.Ed., RN, NPD-BC, CRNI
Lynn Hadaway Associates, Inc.
PO Box 10
Milner, GA 30257
Website http://www.hadawayassociates.com
Office Phone 770-358-7861
Thanks for the info Lynn.
I am a bit confused on the mixing method though- I thought with the mixing method you attach an empty syringe, withdraw and infused about 4 or 5 times and then your last withdraw is what you use for your sample.
Also the article that you mentioned in that previous post is:
Anne Marie Frey Drawing Blood Samples From Vascular Access Devices
Journal of Infusion Nursing
Vol.26,No.5, September/October 2003
Lynn,
Do you know if there is any data supporting the mixing method and the accuracy of samples?
Thanks,
-Tom
Yes, there is but I don't have them for immediate use.
Lynn Hadaway, M.Ed., RN, BC, CRNI
www.hadawayassociates.com
Lynn Hadaway, M.Ed., RN, NPD-BC, CRNI
Lynn Hadaway Associates, Inc.
PO Box 10
Milner, GA 30257
Website http://www.hadawayassociates.com
Office Phone 770-358-7861