Saturday Morning Brunch VI

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.

The Responses:

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

Warm regards

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

Chief Perfusionist

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… 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.

Best regards,

Tom Utsey

Thomas W. Utsey PA, CCP

Chief Perfusionist

Roper Heart & Vascular Center

Phone – 720-8420     Fax – 720-8909

Cell – 475-9827        Pager – 219-1822

EMail – [email protected]

The Following Are PERFLIST entries on the Topic

From:  [email protected]

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 ([email protected])

From:  [email protected]

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

From:  [email protected]

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.

Vince Young

Subject: circuit sterility

From: “eric laliberte” <[email protected]>

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?

17 Feb.08

Nick Trubov

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.


18 Feb.08

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., 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.