ECMO Dialysis H1N1 and MacGyver

Many people have called what I am doing a “MacGyver” approach to supplying ventilators for a possible shortage during a pandemic. In case you are not aware, MacGyver was a character on a TV show. The clever solutions MacGyver implemented to seemingly intractable problems, often in life-or-death situations required him to improvise complex devices. He used knowledge of science and engineering along with a little innovation to build these devices out of whatever materials he had at hand, to free or save the lives of the people he needed to help. Now that I think about it, I don’t think the comparison is too far out.

Last month I was pondering some articles I had read about the treatment of ARDS (Acute Resoiratory Distress Syndrome) in the H1N1 (swine flu) pandemic. These articles said that some of the people that were getting very sick from H1N1 could not be adequately treated using ordinary ventilators. They required the use of HFOV (High Frequency Oscillatory Ventilators) or ECMO (Extra Corporeal Membrane Oxygenation). I researched HFOV and found a published design that I thought could be modified so that people could build these units as emergency pandemic ventilators. http://panvent.blogspot.com/2009/09/high-frequency-oscillatory-ventilator.html
I have more detailed information in my previous post. I also have designs for a more basic ventilator as well.
http://panvent.blogspot.com/2007/03/preliminary-layout-for-open-source.html

When I first heard about ECMO, I thought that surely ECMO must be beyond the scope of the Pandemic Ventilator Project. It is a complex process requiring complicated equipment. I did a little research on it on my break at work. (I work as a dialysis technologist.) As I read about the requirements for equipment to do ECMO, an odd thought occurred to me. Everything that the paper in front of me said I needed to do ECMO was on this machine that was right beside me. That machine is a hemodialysis machine. I did some more searching on hemodialysis and ECMO and found that dialysis is often used in conjunction with ECMO by either using 2 sets of equipment, or just by adding a dialyser to the ECMO circuit, but I could find nothing about actually doing ECMO on a dialysis machine.

I thought, “Now this is an original idea!” I quickly put my thoughts together and posted it as a possible help for pandemic flu sufferers. I contemplated it again later and thought that it may even have some advantages over conventional ECMO in that citrate anticoagulation could be used. I asked for comments on the blog which were mixed, but nobody said they had done it, were considering it, or had even heard of it being done.
http://panvent.blogspot.com/2009/09/using-dialysis-machine-to-do-ecmo.html

Today I did a little more research. This time it was for CRRT (Continuous Renal replacement Therapy) and ECMO. I found something truly amazing. Someone had already thought of this more than 2 years ago and used it to save the life of a child. (Goodbye original idea.) Here is another of those heroes I love, like the people that built ventilators to save the lives of children during the polio epidemic. http://panvent.blogspot.com/2008/01/everything-old-is-new-again.html

This person is Dr Abhay Divekar of the Winnipeg Children’s Hospital Health Sciences Centre. He used his idea of doing ECMO on a dialysis machine to save the life of Keith Porcher. The spokesman for the hospital told a news conference “We felt the baby had no other option, that if this experimental procedure wasn't going to be tried, the baby was going to die."




Dr. Divekar, (a true MacGyver, someone should present you with a gold Swiss Army knife) you are a hero in my eyes, and I would love to talk to you some time. I have plans to post a hall of fame page in the future describing every one I could find that built ventilators in an emergency to save someone’s life (most from the polio years). You will definitely be on that page.




So now doing ECMO on a dialysis machine seems much closer to a viable option for emergency use in a pandemic. I even found something about using citrate with ECMO. Vanderbilt University is doing a study on citrate use in babies on ECMO.

CBC radio ran an interview they did with me about the Pandemic Ventilator Project on the Oct 3 episode of White Coat, Black Art. you can get the podcast version here:
http://podcast.cbc.ca/mp3/whitecoat_20091003_21062.mp3

The part about the Pandemic Ventilator Project is at the end.










Here are the links.

JAMA article shows that most patients with severe H1N1 that are treated with ECMO survive
http://jama.ama-assn.org/cgi/content/full/2009.1535

Winnipeg surgeon "MacGyvers" artificial lung
Dialysis machine transformed into heart/lung bypass, saves newborn http://www.nationalreviewofmedicine.com/issue/2007/03_15/4_advances_medicine1_5.html

Rescue ECMO
ECMO used on CRRT machine in Winnipeg
http://www.hsc.mb.ca/press_release22.doc

Experimental artificial lung saves baby
http://www.cbc.ca/health/story/2007/02/16/lung-baby-porcher.html?ref=rss

Study Using Citrate to Replace Heparin in Babies Requiring Extracorporeal Membrane Oxygenation (ECMO), Vanderbilt University
http://clinicaltrials.gov/ct2/show/NCT00968565

MacGuyver at IMDB
http://www.imdb.com/title/tt0088559/

Using a Dialysis Machine to do ECMO

(There is more on ECMO on my Oct 1, 2009 Posting)

http://panvent.blogspot.com/2009/10/ecmo-dialysis-h1n1-and-macgyver.html

Many of the recent case reports indicate that sophisticated machines are required to treat the patients infected by the current novel H1N1 strain of influenza. Basic ventilators such as the existing Pandemic Ventilator Project designs may not be adequate for these H1N1 patients that develop ARDS. Pandemic Ventilator Project type units, however could possibly be utilized on other existing patients to free up more sophisticated equipment for patients requiring advanced therapies. I have also found a design for high frequency oscillatory ventilator that I posted (here).

Another technology that almost certainly will be in shortage during the pandemic is access to ECMO (Extra Corporeal Membrane Oxygenation) machines. ECMO machines oxygenate the blood directly using a gas permeable membrane. These machines can keep people with severely damaged lungs alive long enough for their bodies to repair their damaged lung tissues. There is very little of this equipment around. Many centers do not have any ECMO machines, or have only one.

Consider this:
An ECMO machine pumps blood from the patient, adds an anticoagulant, runs it past a gas exchange membrane to remove CO2 and add O2, regulates the blood temperature with a heat exchanger, removes air bubbles via drip chambers, checks incoming and return pressures, and has safety systems to ensure air is not infused, or pressure limits are not exceeded.

A dialysis machine pumps blood from the patient, adds an anticoagulant, runs it past a dialyzing membrane to stabilize electrolytes and remove toxins and fluid, regulates the blood temperature by controlling dialysate temperature, removes air bubbles via drip chambers, checks incoming and return pressures, and has safety systems to ensure air is not infused, or that pressure limits are not exceeded.

Hemodialysis System

They are pretty similar eh?

Note that terminology for blood access is opposite in ECMO vs hemodialysis.

• In ECMO, the port where the blood is drawn into the pump is termed the Venous line and the port where the blood is returned to the body is termed the Arterial line.
• In Hemodialysis, the port where the blood is drawn into the pump is termed the Arterial line and the port where the blood is returned to the body is termed the Venous line.
• In CRRT, (a form of hemodialysis) the port where the blood is drawn into the pump is termed the access line, and the port where the blood is returned to the body is termed the Return line.

The Hemodialysis picture is from METU BIOMAT, and the ECMO picture is from Medscape. (Note there is an error in the Medscape ECMO drawing, both pressure ports are named "Post-Membrane Pressure Monitor". The lower one should be named "Pre-Membrane Pressure Monitor) Note also that fluids and heparin are normally infused post pump in hemodialysis, as this method is usually considered a safer method. Air removal, and monitoring safety systems are also not in the ECMO picture. Both VV-ECMO and Hemodialysis can use a Jugular Venous Dual Lumen Catheter for access.

VA-ECMO vs. VV-ECMO
There are two types of ECMO. VA-ECMO or Venous-Arterial ECMO, has a more complicated method of attaching to the patients circulation system. VA-ECMO operation is similar to the use of a heart-lung bypass machine in that it replaces the function of both the heart and lungs of a patient. VV-ECMO or Venous-Venous ECMO, has a less complicated method of blood system access. It is done using high flow central line catheters similar to the ones used for dialysis. It replaces only the lung function of the patient.

Some patients with H1N1 are getting lung damage and progressing to ARDS. They may require ECMO because their lungs are so damaged that they can no longer provide enough gas exchange to maintain other body functions. A ventilator may not be adequate in these situations. The heart is not usually compromised. These patients could benefit from VV-ECMO if a machine was available. As stated earlier, available ECMO machines would probably be in very short supply during the pandemic.

You can see that the equipment for ECMO is very similar to the equipment required to perform dialysis. In fact CRRT or SCUF are sometimes done in order to control electrolyte and fluid volume levels by adding a dialyser to an ECMO machine without needing any additional equipment.

It seems to me that one could do VV-ECMO treatments using a dialysis machine with a diffusion membrane oxygenator attached in line on the blood tubing set. Some extra gas and oxygen regulators and controls may also be required. If a standard hemodialysis machine is used, it can be run at a low dialysis flow rate (available on machines such as the Fresenius 2008K) to run in a SLED (Sustained Low Efficiency Dialysis) mode continuously. I would like to hear comments from people that have worked with ECMO equipment to hear if they think this is at all feasible.

This Just in (Sept 15, 2009)

Article in New York Times about ECMO use in H1N1 pandemic and potential shortage of ECMO machines.
http://www.nytimes.com/2009/09/16/health/research/16flu.html

Lancet article about the efficacy of ECMO for severe influenza treatment.
http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(09)61069-2/fulltext

Bloomberg article on using ECMO for near death swine flu cases.
http://www.bloomberg.com/apps/news?pid=20601080&sid=a3B182GF_auk

Belfast Telegraph article about ECMO
http://www.belfasttelegraph.co.uk/news/health/article14493762.ece;jsessionid=80D2A25F7E4033BF410D32971134D6DA?postingType=posting&mode=thanks&postingId=14493924

Update, Sept 18 2009

I have been thinking about this doing ECMO using a dialysis machine for a few days now. So far I have not had any comments either for or against on this blog.

I have done some further research into the equipment required for ECMO and some of the problems with ECMO therapies. It appears that maintaining systemic coagulation using heparin is sometimes a problem. Patients may not properly respond to the heparin therapy, they may have allergies, or there may be bleeding problems associated with systemic coagulation. These are problems that are also very common in hemodialysis and CRRT therapies. One solution to this problem is to use regional citrate anticoagulation. Citrate is infused into the blood circuit at the blood access port to initiate anticoagulation and calcium is infused at the blood return port to cancel the effect of the infused citrate.

This can be more complex than straightforward heparin infusion because the infusion of these chemicals also alters the calcium, pH, fluid volume and sodium levels of the patient. In CRRT and SLED therapies these parameters are monitored and controlled by adjusting the sodium and bicarbonate levels of the dialyzing and infusion fluids. Patient fluid volumes are also easily controlled by the dialysis machine.

Regional citrate anticoagulation has been shown to significantly extend the filter (dialyser) life compared to heparin coagulation by reducing clotting. It is sometimes used when the patient has HIT (Heparin Induced Thrombocytopenia). Regional citrate anticoagulation can also reduce other complications that would occur when using systemic anticoagulation protocols.

During a pandemic, it may be difficult to obtain enough membrane oxygenators to do ECMO. It is reasonable to assume that regional citrate anticoagulation could also extent the serviceable life of the membrane oxygenator by reducing clotting in the device. It will be important to make the best use of whatever supplies one has on hand. If it is indeed possible to use a dialysis machine to do ECMO, and also employ regional citrate anticoagulation with it, this could be a good way to save more lives with the possibly limited supplies available.

Here is a link to a PubMed abstract of an ASAIO journal article about using regional citrate anticoagulation with ECMO.
http://www.ncbi.nlm.nih.gov/pubmed/16883129?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum

Some More Info if this Intrigues You...

JAMA article shows that most patients with severe H1N1 that are treated with ECMO survive http://jama.ama-assn.org/cgi/content/full/2009.1535

Some general Info on ECMO systems and complications
http://www.anzcp.org/CCP/Clinical%20applications/ecmo.htm

Here is a link to a Patent for an ECMO system
http://www.google.com/patents/about?id=QoIcAAAAEBAJ&dq=ECMO

CDC info on the use of ECMO and CRRT on novel A H1N1 patients.
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm58d0710a1.htm



Response to the first comment by Anonymous (see below)

Thank you for your comments. I have been waiting to get some feedback on this issue. Just to clarify, ELSO is Extracorporeal Life Support Organization centered at the University of Michigan.

Now you have question about the origin, purpose and legitimacy of the Pandemic Ventilator Project. It was started on Feb 22, 2007 to promote alternative methods of supplying additional ventilators during a pandemic. In order to reduce the death toll of people either ill from a pandemic or those who would be denied life support so that the ventilator they are using could be used to save a pandemic victim (due to triage protocols). Now when you question legitimacy, I am not quite sure what you are after. I am not trying to defraud or manipulate anyone, and my motives for the project are entirely humanitarian. It is not a commercial venture; in fact I have spent a fair bit of my own time and money on it. All of my work and postings are available for you to view and see for yourself. Now if by legitimacy, you mean authority, I really have none. The opinions I express are my own. It is up to the reader to determine if my arguments are rational and my sources of information are valid.

Now when you warn against an untrained person just setting up ECMO on a dialysis machine when no prior testing or feasibility studies have been done you are absolutely correct. When I proposed this idea, it was for people that are qualified to do ECMO treatments to try to find innovative alternative ways to provide this potentially life saving treatment even if there were a shortage of existing ECMO equipment during a pandemic. I was hoping that knowledgeable people could look at the idea and see if they could make it work safely rather than dismiss it out of hand. Perhaps a someone could find a solution to this problem with the pumps that you mentioned.

Now when you assuredly state that there will be NO shortage of ECMO systems in the US, I do not think you can say that for sure. When we have Dr. Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota (CIDRAP) http://www.cidrap.umn.edu/ worried about a shortage of ECMO machines http://legal-ledger.com/item.cfm?recID=12283 , http://www.startribune.com/lifestyle/health/59253022.html?elr=KArksD:aDyaEP:kD:aUbP:P:Q_V_MPQLa7PYDUiD3aPc:_Yyc:aUHDYaGEP7eyckcUr, and with Dr Dr. Giles Peek of Glenfield Hospital in Leicester, England talking about how few the number of ECMO machines are available in Britain. http://latimesblogs.latimes.com/booster_shots/2009/09/bypassing-lungs-helps-swine-flu-pneumonia-victims.html The World Health Organization is also warning developed countries "to anticipate this increased demand on intensive care units, which could be overwhelmed by a sudden surge in the number of severe cases." http://news.eirna.com/209051/h1n109-who-issues-warning-on-second-wave-of-pandemic

There is agood chance that the current H1N1 pandemic will remain mild and within the ability of our current infrastructure and surge capacity to manage, But I do not believe anyone can definitely say that this will be the case.

What you say about legal liabilities is unfortunately sadly true. The heroic measures undertaken by individuals during the polio epidemic to build their own ventilators to save the lives of children could never happen in today’s legal liability climate. The only hope for that is if legislatures provide legal liability exemptions to the individuals that decide who gets which machine and treatment in a pandemic. Under today’s legal climate it is more prudent for a physician let his patient die by denying access to a potentially life saving treatment than to risk a lawsuit by using an uncertified device.

I must say in defence of any nephrology professionals that read this, hemodialysis is also a type of life supporting treatment that is done extracorporeally. Most of the complications that can occur in VV-ECMO can also occur in hemodialysis. Hemodialysis is routinely done in a safe mode by trained individuals. There were over 300,000 patients safely dialyzed for more than 150 million hours of treatment in more than 4000 centers in the US last year alone.

Clarence Graansma