Venipuncture question

[pine138]

Hey!

Had an interesting poke the other day and was wondering if some of the more experienced members could weigh in.

I was collecting a set of peripheral cultures from a hand vein which was quite palpable, during this poke, I initially got blood return followed by a high pitched squeaking (which I can only describe as being akin to writing on a white board with high velocity).

After the squeaking, blood flow ceased. At this point, I advanced the needle along the vein, to which I received blood flow (2-3 seconds) followed by squeaking and the loss of blood flow. I noticed that during this time, advancing and withdrawing the needle along the vein produced the same result (blood flow, squeaking, loss of blood flow)

I am curious what you think about this. I have my own contrived theory but I would like your input.

Thanks!

[Wuzzie]

It was a valve.

[PeakRN]

It is from the vein wall bouncing against the tip of the needle or angiocath as you drain the blood out. As blood refills or you reposition it will temporarily stop but if you again drain enough blood it will start again. This tends to happen more will smaller vessels, for example in the hand.