Saline Flush Guidelines

Columnist · Aug 25, 2012

Moved to Nursing and Patient Medications for more response.

iluvivt, BSN, RN · Aug 28, 2012

I must ask are you having problems with maintaining patentcy of your peripheral IVs? I see my office copy of the current INS standards are missing as I was going to give you their guideline with their references and the level of evidence rating for the recommedation. I have a copy at home too so if you are interested in that please let me know. The idea of a push pause flush came about in the 90s for a technique to flush central lines however, the current research indicates it is of no value in decreasing occlusion rates or biofilm formation. ....For a central line a slow even and study flush with an appopriate sized syringe for that product should be used. I do still see a push pause flush on some policies though for a CVC flush technique. To decrease occlusion rates most IV educaters will stress other strategies such as timely flushes....using a proper volume esp after a blood draw and using the appopriate technique (based upon typesof NC you are using)and treating PWO's and thrombotic occlusions right away with Tpa. I have NEVER seen any recommendation for a push pause flush on a locked PIV. Again, if you are having high rates of occlusion on your PIVs you need to try and narrow down the cause. I find its is usually a lack of a timely flsuh or worse yest not even flushing at all after disconnecting an intermittent infusion or they are doing an improper flush based upon the typs of NC you are using. Do you know what type of NC you are using?

MunoRN, RN · Aug 29, 2012

There is no available research on pulsatile flushing, then again there are not RCT's that support the idea that it's safer to jump out of an airplane with a parachute than without one, sometimes things are just that obvious that there's no reason for studies.

There is however a wealth of evidence from the field of fluid dynamics to support pulsatile flushing. When fluid flows through a tube, it quickly establishes laminar flow with the most flow at the center of the lumen, decreasing to absolutely no flow at the wall of the lumen. This becomes even more pronounced where the cross-section of the lumen becomes irregular, such as with valves, which is why Bard specifically recommends pulsatile flushing be used with their PICC's.

In order to clear a fluid/suspension from the entire lumen, rather then just the very center, a pulsatile flow is needed. Each time flow stops it allows for dispersion laterally (from near the wall to the center) of the fluid you are trying to clear from the line, as the the flow starts again the fluid that has moved to the center flows downstream, repeating this will continue to clear the fluid near the wall that would otherwise remain with a single, constant flush.

Lynn Hadaway has long been opposed to pulsatile flushing, although she provides absolutely no evidence to support this. Her concern is that this creates more shear stress at the wall potentially breaking off more biofilm, although according the laws of physics pulsatile flushing has the same peak Reynolds number and therefore the same shear stress. Many, many posters on another topic board she frequents have pointed out to her that she is incorrect, although so far the most she's admitted to is that pulsatile flushing is preferred for clearing blood from a line.

If you ever get the chance I suggest watching a clear line such as a transduced line being flushed, the difference between pulsatile and constant flow flushing is plainly obvious.

iluvivt, BSN, RN · Aug 30, 2012

Yes I am aware of Hadaways opposition to a pulsatile flush although I have not taken it out of our policy either. I cannot find any evidence that it is effective..so I say it cannot hurt but it may not help. Heck I am just happy when they flush a CVC/PICC right after use and do not leave lines connected to CVCs that are OFF. For PIVs though I do not really see any benefit in the pulsatile flush in regards to decreasing occlusion rates. Again before you come up with solutions you really need to narrow down what the problem is or what you are trying to prevent?