DIAPHRAGM PACING
SYSTEM
What is a diaphragm pacing system and which patient can
benefit most by having one. Welcome to the Clinician's Roundtable at ReachMD,
the Channel for Medical Professionals. I am your host, Bruce Bloom, DDS, JD
and joining us to discuss usage for diaphragm pacing system beyond ALS it is
Dr. Raymond Onders, M.D., F.A.C.S., Associate Professor Of Surgery at Case
Western Reserve University School of Medicine in Cleveland, Ohio. He is also
director of minimally invasive surgery at University Hospital Case Medical
Center.
DR. BRUCE BLOOM:
Dr. Onders welcome to ReachMD.
DR. RAYMOND ONDERS:
Thank you for having me here today.
DR. BRUCE BLOOM:
Tell us about the diaphragm pacing system and how it helps
ALS patients to regulate their breathing?
DR. RAYMOND ONDERS:
Well what we found our initial pilot trial and we have just
completed a large multicenter trial throughout the United States they allows us
to maintain diaphragm strength, allow us to maintain the good type 1 muscle
fibers that we need in patients with ALS. We have actually changed the
way of the patients are dying from this need for ventilator to having
unfortunately with ALS are still losing all of their other motor neurons. They
are still unable to move and eventually can't communicate. We have changed
kind of the usual way of death from respiratory failure to when they choose to
die because they can no longer communicate or they have developed other
problems from ALS.
DR. BRUCE BLOOM:
And explain the mechanics of what the DPS does for these
patients? Why does it help ALS patients?
DR. RAYMOND ONDERS:
In ALS patients as in our other groups of patients we are
implanting electrodes directly on the diaphragm. The diaphragm is a very
interesting muscle at one of key, New England journal articles that just came
out in March of this past year that showed that just one night on a ventilator
you lose 50% of your type 1 muscle fiber as we sit here talking about 70% of my
diaphragm is type 1 slow-twitch muscle fiber that can fire every minute of
everyday without tiring out. What occurs is that the diaphragm actually very
rapidly from disuse with 50% of the muscle mass lost within one day of being on
a ventilator. What we found in ALS patients is that when they have lost some
central control of the diaphragm, develop type of central sleep apnea, so at
night when they are on their usual therapy of noninvasive positive pressure
ventilation their diaphragm muscle is not firing at all and therefore that
diaphragm is getting a little bit weaker from disuse. We also found that there
is a much higher proportion of type 2B muscle fiber in ALS patients that we can
convert that to type 1, so those are kind of some basic effects that we have
seen in our ALS patients especially those with more of the upper motor neuron involvement
of ALS.
DR. BRUCE BLOOM:
So the ALS patients are a new cohort that you are trying
this on. Tell us about the other types of patients that use DPS.
DR. RAYMOND ONDERS:
Well our initial research was in the spinal cord injured
patients. Obviously you had a catastrophic C2 injury, will become a
quadriplegic ventilator dependent it changes your life completely. A 40-year
old that becomes a ventilator dependent quadriplegic has a life expectancy of
only 7 years if they are on a ventilator, that's a significant change in the
life expectancy. If you are one of those few that actually could still breath
the exact same injury your life expectancy is 20 years, still not great for a
40-year old, but as we all know when you on a ventilator you have a high
incidents of pneumonias. Ventilator system ventilate the anterior lobe and due
to this chronic posterior lobe collapse. We have chronic positive pressure
built trauma on your lungs, so that significantly effects your survival. So
our initial the research group on those patients. Interestingly Christopher
Reeve was our second successful patient. The first one not on first try, the
first patient we had to do is second time to get it to work as we had changes
in how we looked at things and he said even before the surgery you know
"what do I have to lose it is a simple laparoscopic procedure. I am a
quadriplegic so I can get off the ventilator it is a huge change in my lifestyle".
We subsequently did a 50 patient multicenter trial and got FDA approval as a
monitoring device in June of this past year and what we showed on those 50
patients was that we got all of them off the ventilator except the second
patient which changes their quality of life significantly. That really was our
initial group that led to our ALS group and really the data from those two
groups have shown us that we may be able to help just anybody on a ventilator
with this percutaneous system.
DR. BRUCE BLOOM:
How long does the surgery take and what is involved in it?
DR. RAYMOND ONDERS:
Well the surgery takes little over an hour. It is about the
same technical difficulty as a gallbladder operation, which is done over 500,
000 times in United States. It is a laparoscopic procedure where we put a TV
camera in by the belly button. However, the key technical detail of this
operation, which was developed, was that we can’t just randomly put the
electrodes in the diaphragm. We have to map the diaphragm. So, then they have
developed the suction-cup electrode where we move it around the diaphragm to
stimulate the diaphragm, we can measure change in abdominal pressure, so the
higher the pressure increase, the stronger the diaphragm contraction. We can
also visualize this so this is both a quantitative look at the diaphragm and a
qualitative look at how the diaphragm is contracting. Once we identify the
best diaphragm implantation we put the electrodes in there. We put 2
electrodes in each diaphragm initially because that 1 electrode might break.
Fortunately, our graduate student that developed this electrode Peterson, we
named it the Peterson electrode after him, this electrode has never broken in
the patients, a great little electrode, and we subsequently develop a way
because for each electrode I can stimulate them with different settings so that
I can try to maximize the contraction and get the best breadth by setting each
electrode separately and then I kinda feel like an ophthalmologist saying be
like #1 or #2 better with how they breath as opposed to how we see things.
DR. BRUCE BLOOM:
And these breathing for those patients 24 hours a day have
any impact on the diaphragm or the other muscles of the area?
DR. RAYMOND ONDERS:
It is very interesting because some of the older list for
ALS that is that over exercising can make it worse where obviously exercising
on diaphragm keeps stimulating it 24 hours a day. From an evolutionary
standpoint the diaphragm is made to be utilized every minute of every day and
so really stimulating every minute of every day is just like our own natural
breathing, it does not cause any problem as that New England journal article
showed that just not moving a diaphragm for just one night cause the change in
the muscle composition that converts the type 2B muscle fiber faster than any
other muscle. The atrophy is faster than every other muscle. It needs to move
every minute of everyday. You should never rest the diaphragm.
DR. BRUCE BLOOM:
If you have just tuned in you are listening to The
Clinician's Roundtable on ReachMD, The Channel for Medical Professionals. I am
your host, Dr. Bruce Bloom, DDS, JD and joining me to discuss usage for a
diaphragm pacing system beyond ALS is Dr. Raymond Onders, M.D., F.A.C.S.,
Associate Professor of Surgery at Case Western Reserve University School of
Medicine and director of minimally invasive surgery at University Hospital Case
Medical Center.
So where are else in the world is this being used and for
what indications?
DR. RAYMOND ONDERS:
It has completed year being approval for spinal cord injury
and for ALS and any neuromuscular disease, so we have actually implants that
have been done in Paris at Pitié-Salpêtrière Hospital and Charity hospital in
Berlin and Barcelona, in Iceland and we have numerous other sites starting in
Europe. Again interesting is that I have been involved to this research for
over a decade now that we doubled the amount of patients being implanted every
6 months. In the United States, we just got approval for spinal cord injury
indication and presently we are just in the waiting pattern with FDA for our
ALS applications. We have completed our long-term multicenter trial and we are
just looking and waiting for the final announcements for the data before we
apply for FDA approval for ALS in United States. In our future application, we
are really looking on just anybody on a ventilator utilizing our data from
spinal cord injury in ALS it looks like we may help any patient that is on a
ventilator as we recently learned in the United States is that hospital won't
get paid if the patient develops ventilator associated pneumonia. Why do
people get pneumonia on the ventilators? The ventilators only cause expansion
of the anterior lobe so you get the chronic posterior lobe collapse. We have
shown already that by stimulating the diaphragm in conjunction with the
ventilator at the same time, which causes the air, go to the posterior lobe and
therefore we do not get that posterior lobe collapse. So we also have a
temporary type of diaphragm pacing system where we just would utilize at the
same time they are on the ventilator to maintain type 1 muscle fibers help
maintain posterior lobe ventilation and hopefully decrease ventilator
associated pneumonia.
DR. BRUCE BLOOM:
What other kinds of physicians you need to work with to make
sure that the patient is eligible for this. Are you are working with the
neurologist and others that are treating the patient?
DR. RAYMOND ONDERS:
Absolutely, I mean, this has been a team aspect to start
initial aspect. We have had critical care nurses, or pulmonologist here,
neurologist here, and really for ALS patient you know the interesting I am a
general surgeon and I treat lot of ALS patients as my researches take me in
that area, but the first thing I tell any ALS is the most important thing is
that get yourself a good neurologist who will take care of all aspects of your
ALS. There are the one specialized in this. So, I really even in my own
practice here I do not even see a patient for consideration of this until the
neurologist has helped manage all of the other conditions that they will have
with ALS. ALS is a terrible disease and they need to have a good neurologist
to help take care of all those other aspects that will actually help the
quality of life and then, once they have kind a stabilized from that aspect
then we can try and do something to help them even further.
DR. BRUCE BLOOM:
And wha date are you hoping to get approval from the FDA for
its use in ALS.
DR. RAYMOND ONDERS:
I think that would be a whole other segment is the role of
the FDA in trials. I think as we all know the FDA is overworked. There is no
doubt that at presently we don't have enough manpower at FDA. There is one
aspect that the government has called humanitarian used designation and that is
what we utilize for our spinal cord injured patients that still is a very slow
process with FDA and presently we are in negotiation with FDA to try to offer
this for patients with ALS. Unfortunately we think it will probably be a good
6 months before anybody in United States any further ALS patients will be
offered this. Obviously, we have full approval in Europe and our data looks
good but just is a slow process, which is appropriate. I mean the FDA has a
lot of work to do and we need to support them in their work, but if you are an
ALS patient, obviously having to wait for approval it is between living and
dying.
DR. BRUCE BLOOM:
Could you go outside at the United State if you are an ALS
patient and get this done?
DR. RAYMOND ONDERS:
Presently, you know we have approval in Europe and it was an
interesting aspect though is that it is to difficult to travel with ALS and you
know this is common question ALS patients ask me and if you are fairly far
along on your disease course just traveling on an airplane and all other aspect
may be enough to push over the edge. I think that there is a lot of risks with
doing that and it gets the medical tourism industry. It is a difficulty
industry because officially if they are plant somewhere else is that they can’t
get product support here in United States. So I think it is difficult aspect.
I hope that the working closely with our government agencies that will be able
to offer this for ALS patients in United States.
DR. BRUCE BLOOM:
Tell us about it use in critical care patient who don’t have
ALS and how would you be using this and why?
DR. RAYMOND ONDERS:
It seems that obviously we have been looking at this very
carefully. Now this is a whole new avenue of surgery that is called node
surgery, which my all other research aspect is this other minimally invasive
surgery. May have heard of natural orifice transluminal endoscopic surgery
where we can actually now take out gallbladders through the patient's mouth or
a female patient’s vagina with no abdominal incisions. We actually developed
the way to actually put this diaphragm pacing system and just at the same time
as our percutaneous endoscopic tubular PEG. Interestingly, I met the same
hospital where the PEG was initially developed Jeff Hopkins my chairman and so
we have a very long experience with these aspect for helping patients in the
ICU and so we believe that at the patient beside in the ICU we can actually
implant the diaphragm pacing system at the same time as our feeding tube. The
data looks very promising by maintaining diaphragm strength we can help
patients to get off the ventilator, 40% to 50% your time after initial injury
is just to re-strengthening the diaphragm by electrically stimulating it
earlier we will maintain that strength decrease the posterior low collapse that
can lead to pneumonia and hopefully improve the quality and survival benefits
in ICU.
DR. BRUCE BLOOM:
Is your group looking at using electrical stimulation in any
other area of the body?
DR. RAYMOND ONDERS:
Case West Reserve where I am actually and faculty has had
the functional electro stimulation area. Over the years, they have had system
for spinal cord injury. They moved their hand for quadriplegic, we have
walking system are being developed, it is kind of you know as we all would like
to cure spinal cord injury and get that spinal cord to regenerate or kind of
get pass the bruise and the electrical problems. We can now learn implanting
enough electrodes to get the body to move. It is never as good as it was
initially. So we have a group working on a freehand system where you can move
the arm or walking system for patient, a standing system, as we would like to
say is that we believe we can put electrode just in any muscle that will help
the patient. The diaphragms are very interesting one because if the diaphragm
contracts you breath. Any other muscle like your hand muscles are so
complicated the grasp, the move that 360 is lot harder to control, it is much
more difficult but we are doing a lot of positive work in that area.
DR. BRUCE BLOOM:
I want to thank our guest Dr. Raymond Onders, M.D.,
F.A.C.S. We have been discussing usage for diaphragm pacing system for the
patients beyond ALS.
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