Questions Regarding ECC Prime
Duration, Sterility, Membrane Functionality…
1st Week of April
To see all the of the Saturday Morning Brunch series click here.
It’s All About the Timing …
Well it’s been an interesting week. Two cancellations in a row, and a wet circuit that I primed Wednesday afternoon and plan to use for a Friday morning AVR / CABG / MAZE procedure. I primed with crystalloid only, and 2.5 K of heparin. It is a microcircuit using a Capiox 25 oxygenator.
Of the course the age old question of “how long can you keep a wet circuit for?” came up. So I dug through a list of responses from Perflist of the exact same question when I asked it awhile back. Here are the answers I got back then. If anyone has more to add- please drop a line in the comments section of this post.
As it turns out, as I was writing this post- I got called in for an emergency and had that primed circuit ready. But institutional policy prevented me from using it (less than 24 hours since primed). What a coincidence . 🙂
To go directly to comments sections click here.
From: Michael McDonald CCP; Melbourne, Australia
We routinely prime up for OPCABS but keep the pump back from the table and under a plastic cover.
Prime is crystalloid and Heparin only.
We will then happily use this pump any time for up to a week (altering the prime as required).
We have followed this practice for over 20 years (albeit not for OPCABS originally but for when cases were cancelled after priming) and perform around 1200 cases per year.
There are two arguments often given against this practice.
1/ The prime could “grow” stuff. The counter-argument includes that there is no substrate in the prime to feed “stuff”, the prime is sitting under UV lights, we don’t have a septicaemia problem. (In the early days we sampled the prime, threw out the circuit, and tried to grow stuff from unused circuits. After several years of never growing anything we started using the circuits). Lastly if the circuit is assembled and primed in a sterile fashion, it should remain sterile. If the circuit is assembled or primed in a dirty fashion then address that problem.
2/ When used up to a week after priming we (7 perfusionists) have never noticed any change in membrane performance relative to a newly primed membrane.
Out of interest we throw out after a week due to concerns over the centrifugal pump head bearing.
Hope this helps and am quite happy for any discussion
Michael McDonald CCP
From: Mark Moreno: Nebraska Medical Center
We keep our coated Terumo RX25 and RX15 CO2 flush but not primed for OPCABS – we can have the circuit primed, without plegia in less time than it takes the surgeon to cannulate. Plasmalyte A prime – once we are on we will add our goodies – albumin, Bicarb, Mannitol.
We will keep a Plasmalyte primed circuit for 24 hrs – does not affect the membrane at 24 hours – still transfers gas well. We have this written into our policy – Compliance and Infect. Control have no issues since it is sealed.with a slight + gas flow of room air -250 to 500cc/min.
We leave ECMO circuits primed for 30 days with a Quadrox D – have had no gas transfer issues, cultures are neg.
Mark R Moreno BS CCP
The Nebraska Medical Center
From: S. Wiley, CCP
Most manufactures state on the oxygenator insert that a primed oxygenator is good for up to six hours…..after that, they don’t guarantee performance. so, i am thinking that using one that has been primed for over six hours is a possible liability in the event it does not oxygenate well…..perhaps it will develope pulmonary edema…..read the insert; i know medtronic states six hours…….s. wiley ccp
From: Thomas W. Utsey PA, CCP : Roper Heart & Vascular Center
It has been a few years since standby for OPCAB was an issue here. But, we went through a few years of doing it from about 1996 to 2002.
We found very quickly that there was no real need to be primed while standing by. The few times we had to rush on, we were able to prime far quicker than the surgeon was able to cannulate, we estimated seven minutes or less. What we found was that you would from time to time jump the gun and begin to prime when things went south, only to find that the patient (and/or the anesthesiologist) recovered and you did not need to go on. Canning a setup that way was far more acceptable than dealing with the wet setup on every standby…….. how long to keep it or whether to use it at all on another case.
There are four seasoned perfusionists here and we all feel that, in spite of some published data that supports the practice and the fact that we know some people out there do it, we would never be comfortable using a wet setup that had been circulating or sitting for more than 5-6 hours. That’s just us.
It IS our policy to reload all of our pumps after every case, leaving all caps on, etc., and use it for the next case in that room. In other words, we use clean dry setups and have the cut off of 7 days as the limit to the time we will consider it clean. We do not cover or do special draping of the pump. Occasionally, to avoid trashing a six day old set up, we have to move it to another room to use it. We rarely trash a setup anymore.
Been doing all of this for many years.
Thomas W. Utsey PA, CCP
Roper Heart & Vascular Center
Phone – 720-8420 Fax – 720-8909
Cell – 475-9827 Pager – 219-1822
EMail – email@example.com
The Following Are PERFLIST entries on the Topic
Subj: primed pumps
Re: Primed Pumps
We wanted to know the same thing so, our group recently tested 12 complete
extracorporeal circuits for long-term sterility. Six of the circuits were wet
and six of the circuits were dry. Each ECC consisted of an open reservoir
oxygenator (COBE Duo). The circuits were our standard CPB circuit, assembled
and maintained in an unused operating room for seven days. Hospital personnel
were allowed to enter and exit this room with and without masks and use
equipment from this room. All operating room staff were only cautioned
against handling the circuits. Each ECC was cultured at three locations every
eight hours, inside the venous connector, inside the arterial outlet, and
just inside the reservoir lid and on the defoamer. 792 cultures were taken
over the seven-day period, all were negative for any microbial growth. Look
for this paper in JECT sometime in the future. This has given us the
knowledge, that short of sabotage, these circuits are sterile longer than we
previously thought. We under took this investigation so that we could prime
for MIDCAB procedures and still be able to use the circuit later. I hope this
answers part of your question. We are still investigating other questions
regarding this topic and hope to adequately answer them shortly.
Vince Young (WYoung3246@aol.com)
Subj: Standards for dry and wet circuits
We are considering setting up a dry circuit at the end of each day to help
facilitate a faster response time for our nightly call person in the event of
an emergency. Our current standards are 12 hours for a dry setup and 6 hours
for a wet setup. We would like to extend these time limits, and use the
circuit the following morning if it’s not used during the night. Any
literature references concerning contamination times would be greatly
appreciated. Thanks in advance.
Sterility of Previously Assembled Cardiopulmonary Bypass circuits can be
found in JECT volume 25, Number 3, 1993. They found 2.5 days of a dry
circuit to have minimal risk of contamination.
H. Johnson, RRT, CCP
Subj: Re: dry/wet
We wanted to know this same thing. Just completed a study of twelve
extracorporeal circuits, six wet and six dry. Found that both could be
maintain sterile for seven days or more. Our protocol was for seven days so
we hang our hat on that number. We swabbed 792 samples in seven days, all
were negative for an open reservoir system. Watch for this article in JECT in
the future. This study answered a lot of questions for us. We have saved
money by not trashing a pump circuit as well, when we might have in the past.
Subject: circuit sterility
From: “eric laliberte” <firstname.lastname@example.org>
I have an anecdotal report. I had an ECMO circuit CO2 flushed and primed,
but was not required by the patient. I left the circuit in the pump room
for almost 2 months. Before setting-up a new circuit for another
potential ECMO, I did a sterility test of the prime (10 mls) and I cut a
piece of tubing inside the sterile drape, using sterile scissors. The
sterility test result came back negative. I called back the microbiology
department and they assured me it was negative. I was the first one
surprised. The priming fluid was only Normosol-R pH 7.4. Nothing else was
added to the primed. I have another circuit primed at the moment. I will
do another sterility test when I will need to set-up a new ECMO for
another patient. This can take a few weeks still. Is there any other
anecdotal report like this one?
In “my” hospital the written protocol for wet and dry
pumps, set up and left in the operating room is this:
Dry pumps are to be covered with a large blanket or
sheet and marked with the time and date of setup and
the person setting it up and draping it. They are not
to be used if the time they have been left in this
manner exceeds seven days.
Wet pumps are to be left set up for no more than
twenty four hours. But in the last ten years we have
NEVER used a pump that was set up and primed if we had
to leave it in the room that way for more than eight
We have been really lucky, too, since we have not seen
any tigers of ANY sort. I live in Fort Smith,
Arkansas, so the comparison to Columbus, Ohio, may
just be fortuitous.
That is my story and I’m sticking to it.
Pat H. Courtney, Jr. LP, RABT
As I have read these postings it seems obvious that the CPB set ups are
assembled by the perfusionists at the individual facilities. If so, then the
exposure to room air would seem to be the same as the limitation on any
other open component that is used in the OR. To the best of my knowledge,
the time limitation is still 8 hours. Additionally, such open items must be
under the observation of personnel or inside a locked OR room.
It really does not matter that the room air that enters the circuit after
opening the sterile pack does not have any growth media available for
bacterial growth. It is just compliance with a Standard (liability), which
applies to all other opened items.
With this in mind, we developed a simple answer to the question way back in
1991. At that time the CPS circuits were in wide use for deployment in the
cath labs. Utilizing the newly developed technology for that application, we
contracted with both Baxter and Medtronic to provide us with a totally
assembled CPB pack which contained all of the necessary components and was
then sterilized as one unit, in one tray. Later, we had the unit modified to
have two (2) sterile tray packs (cardiotomy + suckers + vent and oxygenator,
reservoir, Bio Head, cardiaplegia) just for ease of handling.
With the two tray system, the tubing end (cardiotomy exit line) that was not
connected, was placed in a clear peel pouch and the pouch was securely taped
to the tubing prior to sterilization. To complete the circuit, the peel
pouch was opened and the connection was made to the reservoir just prior to
We still use this basic pack system (Medtronic) today, except that the
cardiaplegia pack is purchased separately from Sorin/Cobe (the oxygenator
outlet has tubing attached which is inside of a peel pouch, for connection
to the cardiaplegia set).
As the sterile pathways are not opened to air, the CPB system remains
sterile indefinitely and as it is a sealed system, positioning close to
another patient does not pose problems of contamination beyond those of any
other unopened sterile items in the room.
If anyone is interested, the publication is titled
Pre-Assembled CPB Circuits – An Innovative Utilization of Evolving Technology, Vol. 23 #3, pg
125 – 127, J. of Extra-Corporeal Technology, 1992.
Pat H. Courtney, Jr. LP, RABT
Forum: Adult Perfusion
Topic: Dry Pump Setup – How long can it stand Sterile?
Posted By: racine
There was a good article about dry then wet setups in the Journal of
Extracorporeal Perfusion way back in 1997. Many scoffed at the idea of
a dry circuit sitting overnight and even more on a wet circuit over 8
hrs. Frankly, I re-created the study dry then wet with aerobic/anerobic
cultures over 7 days wet and have never grown anything. Careful
attention to aseptic technique, having laminar air flow in the OR and
security of the setup is crucial. I have repeated the same scenario 7
times over the years and have never gotten anything to grow. I even had
a spare setup I was tearing down after being wetted over 4 days and then
had a patient come into the OR coding/CPR in progress/blue from the
chest up that I placed on bypass emergently. We save his life and saw
no indication of any nosocomial issues, sepsis, or adverse SE besides
being blue for almost 30 minutes. So this is what I know- oxygenators
will work even after being wet with Normosol R for 4 days and they do
not grow bugs from 5 different points even after 7 days sitting idle. I
only leave a dry circuit for 30days ( I’ll most likely use it before
then) but it will be draped and in a locked room and OR and away from
traffic. I thought about this again 6 yrs ago when a Pediatric
Clinician admitted to doing the same without complications. If you a
one man operation this is the only way to go. I can still set up and
have a circuit primed in under 10 minutes but given the stress of
prepping under adverse conditions why risk having something misplaced
only to hurt the patient? Is there enough evidence to support this
practice? I say there is and my negative lab cultures and good outcomes
and stats prove it.
1. Homishak, Michael, et al. Sterility of Previously Assembled Cardiopulmonary Bypass Circuits, JECT, 25(3), 1993, pages 84-86.
2. Young, William V., et al. Extracorporeal Circuit Sterility after 168 Hours, JECT, 29(4), 1997, p. 180-184.
3. Searles, Bruce, et al. Investigations into the Sterility of Manually Assembled Extracorporeal Circuits with Vented Reservoirs, JECT, 31(3), 1999, pages 125-129.
4. Chorak, et al, Sterility of Heart Lung Pump Beyond 48 Hours, Am J. Infec, 1990; 18(5): 328-331.
5. Felts, et al, Sepsis Caused by Contaminated Intravenous Fluids, Ann Int Med 1972; 77: 881-890.
6. Holmes, et al, The Microbial Contamination if IV Fluids During Clinical Use, J Appl Bacteriol 1979; 46: 247-277.
7. Klemmack, et al, Investigations into the Growth of Aerobic Organisms in Typical Priming Solutions, Proceeding of the American Society of Extra-Corporeal Technology 37th International Conference, 1999
8. Lonsky, V., et.al. How long can the previously assembled cardiopulmonary bypass circuit stay sterile? Acta Medica (Hradec Kralove). 41(2):91-3, 1998.
9. Chen Gao; Alfred H. Stammers; Rebecca L. Ahlgren, et al, The Effects of Preprimed Oxygenators on Gas Transfer Efficiency, JECT. 2003;35:121-126.