Dealing with wet isolator

[Garry]

Hi All.

Following the ART conference, and some discussion relating to wet isolators and various 'techniques' for dealing with such issues, I thought I share our procedure.

I only have experience with Braun evolution lines that utilise three manometer connections, venous, arterial and pressure at dialyser inlet (for a standard HD treatment).  This procedure only works if there is a bubble trap and spare locking luer fitting on the bubble trap.  In the case of Braun lines the arterial line does not have a bubble trap so our policy would be to change the lines should this become wetted with blood.  If either of the other luers becomes wet we ustilise the item below



- The COP includes guidance to clamp existing wet isolator line and disconnect from equipment
- Attach new transducer protector y-connector above by securing locking luer to top of bubble trap and new isolator to machine.
- As per guidance, technologists are informed of wet isolator so that luer and internal filters/lines can be inspected post treatment.
- Yconnector provides spare connection for attachment of syringe as per original blood lines.

Hopefully useful for somebody out there

[Chris Pearson]

Am I missing something here,have manufacturers started scrimping on isolators and not fitting those with hydrophobic membranes anymore so they don't get "wet" and just need the level pushing back down ?

[Garry]

I assume they are still hydrophobic though our reasoning is:

1.  Latest RA BBV guideline indicates that once wet their ability to prevent moisture crossing can be reduced.  It also suggests replacement if it becomes wet to prevent contamination of internal isolators.  Either way, once wetted with blood staff should inform us and we will check post use, also as per RA BBV guidance.

2. Experience has shown that, though flushing back saline seems to have minimal effect on transducer performance, once exposed to blood the ability to transfer pressure is reduced giving false high or low readings on the equipment.

We allow flushing back if saline reaches the isolator during priming.  The nurse also confirms pressures are as expected following this.  

[Chris Pearson]

Hi Gary,
But surely if they are hydrophobic they should never get "wet" and you could just clamp,attached a syringe full of air,unclamp and push blood back,reclamp,remove syringe and re-connect.
The RA guidelines may just be a re-hash of old data when some units were using cheap hydrophillic or even worse disk filters by mistake.

[Garry]

We always used to just flush back and add second isolator but instances of reduced pressure transfer, maybe even caused by clotting of any blood left in the isolator line, gave rise to our current policy.

[Ian Wilde]

From experience I have noticed that once wetted and then the fluid pushed back we can still see incorrect readings of pressures.

Also, I'm not sure about how people feel now about pushing a load of what could be unfiltered/contaminated air directly into the venous bubble trap?  Maybe it's overkill but some may question it?

Our policy here is that with a wetted isolator it is clamped, removed from the port and a new "leg" put on one of the spare ports on the bubble trap:

[Chris Pearson]

I have found a great Alert Notice from the Veterans Hospital in the USA which deals exactly with this scenario but despite my best efforts I can't post a link to it.

[Andy]

The Isolators/transducer protectors on the blood sets we use are manufactured from Gore Tex 0.2um with a supporting film of polyester. It is my understanding that these isolators are hydrophobic and act as both a gas/air filter and a liquid barrier. The clamp/syringe method is used here.