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1. James C. Eisenach, M.D.
Editor-in-Chief
RE: 200810121 - Esophageal Doppler is an Important Part of
Perioperative Fluid Management (RE: Chappell J, et al.
2008;109:723-40)
Dear Dr. Eisenach,
I would like to take this opportunity to thank you for the incredibly
valuable service you perform as the editor and chief of
Anesthesiogy. Thank you for your careful reading of my letter and
the article itself. The role of TEE in the management of
perioperative fluid administration, in my humble opinion as
explained in my original letter and below, is covered incompletely
and as such is a disservice to our specialty. This incomplete
coverage minimizes an extremely powerful tool that fixes a
fundamental flaw in our understanding of hemodynamics. This
tool also provides a means to make A Rational Approach to
Perioperative Fluid Management a reality.
Please take the 2 or 3 minutes necessary to read this.
I need your help.
I have been a dedicated cardiac anesthesiologist at a tertiary
cardiac center in San Diego for 28 years. We have been using
dedicated TEE in all our heart rooms since 1987 and esophageal
Doppler monitors in all our operating rooms since 1999. I would
like to mention a few observations.
The large multipurpose TEE machines do not allow us to follow
hemodynamics in a continuous real time fashion. We can calculate
snapshot hemodynamics in a time consuming process. This is not
beat to beat real time management. The esophageal Doppler
monitors are different and have distinct advantages.

2. The opportunity to measure flow by multipurpose TEE machines is
limited for the majority of patients by cost issues. The esophageal
Doppler is readily applicable to all intubated patients and can be
used in awake unintubated patients as well. Disposable probes that
can be used for up to 10 days in a single patient cost $170.
Most importantly, we have no fundamental understanding of flow
in the majority of the 35 million patients that we care for each year.
If we use the esophageal Doppler to understand flow we can
improve clinical outcomes. The evidence is substantial, unique to
the esophageal Doppler, and referenced in my original letter.
Without flow it is impossible to understand the simplest of
hemodynamic relationships, Pressure = Flow x Resistance. We can
not understand a 3 variable equation with only one variable. We
need to know 2 of the variables to get an understanding of the
equation. Adding heart rate and urine output to blood pressure will
still allow no basic hemodynamic understanding. This means we
have no understanding of hemodynamics in the majority of the 35
million patients we care for each year. This is an astonishing
fundamental flaw in our knowledge base and in the way we care
for our patients.
Without this understanding we unknowingly bring patients to
recovery areas every day with acceptable blood pressures and heart
rates with unacceptable hemodynamics. We do not recognize this
unacceptability until the multiple compensatory mechanisms that
maintain BP are exhausted and the BP deteriorates. We are then
reacting to an abnormal situation as opposed to actually knowing
the hemodynamics in real time and anticipating the development of
the abnormal situation and taking care of it before it becomes
severely abnormal or unstable.

3. Even in normotensive patients, we can have very low flows and
high resistances and are blind to this without flow measurements.
This is not a good situation for patients and not a good situation for
a profession that is supposed to know what it is doing. And, what
about hypotensive patients? Do we need increased preload, do we
need a vasopressor, an inotrope, a combination? We guess. We
make mistakes and many times are completely unaware of these
mistakes because we see the BP move in the direction we want but
are unaware of the underlying hemodynamics which can change in
ways that may be detrimental to outcomes. The esophageal
Doppler takes away the guess work, so we can specifically
understand and deal with the hemodynamic problem.
The ED brings to our specialty an incredible opportunity to be the
fixers of a fundamental flaw, reap the benefits for our patients and
increase our stature as providers of high quality care.
As an aside, here are the tenants of one of our QI projects. Point 4
is particularly important to our society.
1. With the addition of cardiac output monitoring we gain a
fundamental understanding of the hemodynamic status of each
patient that we care for.
2. If we understand the hemodynamics of each patient we can
optimize them.
3. If we optimize the hemodynamics of each patient in our OR’s
and ICU’s we can decrease hospital length of stay, health care
costs and patient complications.
4. If we are proactive in the enhancement of quality care and create
cost efficiencies we dramatically increase our value. This translates
into stronger and more secure relationships with our hospitals,
insurers, government, medical colleagues, patients, and
community, both regionally and nationally.

4. CMS has seen the evidence base and value of the esophageal
Doppler. It has seen the potential of great cost savings for the
healthcare system that it can provide. CMS has said that use of
esophageal Doppler is “reasonable and necessary” and further that
its use be covered for “monitoring of cardiac output with the
esophageal Doppler for ventilated ICU patients and operative
patients requiring fluid optimization”.
We as a society need to understand hemodynamics in all the
patients we care for and with this understanding properly assure
that all the components of flow are acceptable. We currently do
things backwards. We assure that the pressure is acceptable and
assume the flow and resistance are as well. We all know this is
wrong.
What we need to do to fix this fundamental flaw is to assure that
the flow is acceptable (acceptable preload and contractility) and
the resistance is acceptable. Then the pressure will follow by
default. This is the simple paradigm shift that will fix our
fundamental flaw and improve outcomes. The esophageal Doppler
enables us to fix this problem. Adjusting the preload properly is
just a small part of what one can accomplish with this technology
and why ‘the esophageal Doppler is an important part of
Perioperative Fluid Management” as stated in my original letter.
I am interested in flow and interested in fixing this problem. I have
been a consultant to companies that make ED’s because it allows
us to understand hemodynamics at a fundamental level and enables
us to know what we are doing with the various therapeutic
modalities we use to care for the majority of our patients.

5. First we have to realize and accept the important fact that we have
no understanding of flow and the components of flow in the
majority of patients we care for. Then we have to get that
understanding and use it to improve outcomes as done in all the
randomized controlled trials referenced in my original letter.
Industry will then hop on board and will evolve newer and better
modalities. They will respond when we show them the need. But
frankly, most of us are unconscious about this problem. It’s time to
wake up, to emerge from this unconsciousness.
We need to be aware of this tool and need to correct this flaw.
Flow is important and neglected. I know your time is valuable.
This is important. Please take the time to respond. Please feel free
to share this with any of your clinical colleagues that may be able
to help. How can we accomplish this? I want to see this flaw fixed
before I retire. It will elevate our specialty a quantum level.
Sincerely,
Paul W. Corey, MD.
Director, Cardiovascular Anesthesia
Sharp Memorial Hospital
San Diego, CA.