To pulse or not to pulse

[SarahStep]

Hello to all! As you may guess, I am here like many others, to pick your brains! As a student nurse near graduation I have come to the point where I need to know which way is correct when it comes to PICC line care. In my current Lewis text, we are directed to flush a PICC line while pushing steadily on the plunger. My rational for this is to not effect/put extra pressure on the heart or cause any strangeness with the valves. When I practiced in my local hospital, I assisted with flushing a PICC line and was instructed to not push straight and steady but to pulsate the flush. Rational here was firstly that was what the hospital policy/procedure required but also that if any clots were forming at the end of the catheter that they would be broken off. It is my understanding that at no time is it a good idea to try and break clots off into the patients circulatory system. Secondary to this concern is that I am going to take an Nclex exam in the next 6 months and I keep finding conflicting information...and I just know that this question will come up for me. So can I find any takers?

[VivaLasViejas, ASN, RN]

Late in my acute-care career, I learned to 'pulse' when flushing a PICC. We also used only 10cc syringes too, to decrease the possibility of fracturing the catheter.

But that was then, and this is now, and I haven't flushed a PICC or any other sort of IV line in years.

[Esme12, ASN, BSN, RN]

moved to nursing student assistance for best response.....I tried to edit your poll and I couldn't.....but a very cute poll it is. You may have to re log in to the "yellow" allnurses side with your same ID and password.

[MunoRN, RN]

The purpose of a pulsatile flush, or push-pause flush, isn't to break off clots. When you flush through a line, particularly against back pressure, laminar flow will occur with the most flow occurring in the center of the lumen and flow towards the walls of the lumen decreasing until near the wall there is actually no flow at all. Using a pulsatile flush allows the solution that is not in the center of the lumen to move towards the center through diffusion each time the flow is paused, which then allows it to be flushed down stream. This is particularly important in valved catheters, which is why valved catheter manufacturers specifically recommend a pulsatile flush.

Unfortunately you usually don't get to see what your flush is doing, so it's hard for people to visualize the differences between a constant flush and a pulsatile flush. Transduced lines with VAMPS are great ways to see the differences between the two. If you ever get the chance to draw blood off of a VAMP, try flushing it both ways, the difference will be pretty obvious.

[Music in My Heart]

The point is to achieve turbulent flow inside the catheter instead of laminar flow, the only variable of which you have any control is the velocity of the flush... above a certain velocity (Google Reynolds number if you're particularly interested), the flow will be turbulent. The reason for the pulsatile flow is abrupt pressure differentials that occur during the change from laminar flow to turbulent flow.

Regarding your rationale, consider the relative pressure and volume differences between the heart and the flush... the flush is just signal noise by comparison.