Hemodynamic optimization of the OR patient
Wilbert Wesselink
Disclosure
Employee at Edwards Lifesciences
Agenda
Current practice
Hemodynamic optimization: WHY?
Hemodynamic optimization: HOW?
– Perioperative Goal Directed Therapy protocol
– Hemodynamic monitor
Continuous, minimally invasive: FloTrac
Continuous, noninvasive: ClearSight
3
How many people use “flow” based technologies?
4
How many people use “flow” based technologies?
5
1)Doppler?
2)Pulse Contour?
3)ECHO?
4)Something else?
Where do you this technology?
6
2) Intra-operative
4) Combination
3) Post-operative
1) Pre-operative
WHY?
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Why Hemodynamic optimization?
Complications are not exceptions
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• 84,730 inpatients
• General or vascular surgery
• NSQIP database (designed to record
post-surgical complications until day 30)
Variation in Hospital Mortality Associated with
Inpatient Surgery. Amir A. Ghaferi, M.D., John D. Birkmeyer, M.D.,
and Justin B. Dimick, M.D., M.P.H.
N Engl J Med 2009
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• Complication rate was 24.6-26.9%
• Major complication rate was 16.2-18.2%
Variation in Hospital Mortality Associated with
Inpatient Surgery. Amir A. Ghaferi, M.D., John D. Birkmeyer, M.D.,
and Justin B. Dimick, M.D., M.P.H.
N Engl J Med 2009
129,233 cases
Complication rates depend on the surgical procedure
Surgery Morbidity rate %
Esophagectomy 55.1
Pelvic exenteration 45.0
Pancreatectomy 34.9
Colectomy 28.9
Gastrectomy 28.7
Liver resection 27
Prioritizing Quality Improvement
in General Surgery. Schilling et al.
J Am Coll Surg. 2008; 207:698–704.
129,546 cases
Complication rates depend on the patient
Risk factor Odd ratio
ASA 4/5 vs 1/2 1.9
ASA 3 vs 1/2 1.5
Dyspnea at rest vs. none 1.4
History of COPD 1.3
Dyspnea with minimal exertion
vs. None
1.2
Successful Implementation of the
Department of Veterans Affairs’ NSQIP in the Private
Sector: The Patient Safety in Surgery Study. Khuri et al.
Ann Surg 2008
WHY Hemodynamic optimization
Complications are not exceptions
Complications are costly
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Extra cost $
$6358
$12802
$42790
2250 Patients Undergoing General and Vascular Surgery
Synergistic Implications of Multiple
Postoperative Outcomes. Melissa M. Boltz, DO, Christopher S. Hollenbeak, Ph.D.,
Gail Ortenzi, RN, BSN, and Peter W. Dillon, M.D.
Am J Med Quality 2012
Complications have a cost
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More simple and reliable approach
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More simple and reliable approach
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+$18,000
WHY Hemodynamic optimization
Complications are not exceptions
Complications are costly
Complications are responsible for prolonged LOS and readmissions
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WHY Hemodynamic optimization
Complications are not exceptions
Complications are costly
Complications are responsible for prolonged LOS and readmissions
Complications affect long-term survival
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WHY Hemodynamic optimization?
Complications are not exceptions
Complications are costly
Complications are responsible for prolonged LOS and readmissions
Complications affect long-term survival
Hemodynamic optimization is KEY to prevent post-surgical complications
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Where do we want to be?
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Target zone
HOW?
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Start here
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A large body of clinical evidence* demonstrates
If you maintain your patients in
the optimal volume range,
you can reduce
post-surgical complications,
LOS and associated costs1-4
Hemodynamically optimize your patients using:
Dynamic and flow-based parameters
A Perioperative Goal-Directed Therapy (PGDT) protocol
*35+ RCTs and 14+ meta-analyses
HOW
Too Dry Too Wet
Goal
Co
mp
lic
ati
on
s
Fluid Status High Low
Goal Directed Therapy
Protocols
– SV driven
– Driven by dynamic parameters like SVV
– DO2i driven
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Edwards Hemodynamic Measurements From Maximal-Invasive to Non-Invasive
Invasiv
en
ess
Right Heart
Thermodilution
Swan Ganz
Transpulmonary
Thermodilution
VolumeView
Minimally Invasive
Cardiac Output
FloTrac
Non-Invasive
Cardiac Output
ClearSight
Catheter
through the
heart
One venous
and one arterial
catheter, cali-
bration needed
One arterial
catheter, auto
calibrated Finger cuff
Global trend for Hemodynamic measurements & treatments
– Non Invasive Cardiac Output
• Volume Clamp Method
– Minimally Invasive Cardiac Output
• Arterial Pulse Contour Analysis
EV1000 Platform with FloTrac & ClearSight
Continuous minimally invasive monitoring
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Measuring Stroke Volume
Pulse Pressure
Vascular Tone
Compliance
FloTrac Algorithm
Pulse Pressure
– Primary correlate for flow
– Pulse pressure is proportional to stroke volume
Vascular Tone
– Uses a polynomial factor called Khi for continuous assessment of waveform elements associated with changes in vasculature
Compliance
– Langewouter’s principle states that
Age, gender, height and weight inversely correlated with aortic compliance
3 basic functions of the FloTrac algorithm for calculating stroke volume
FloTrac System Algorithm Evolution Continuing to Better Meet the Needs of More Patients
1st Generation Algorithm
• Introduced Automatic Vascular Tone Adjustment (10 min avg)
• Data base Patients: primarily cardiac patients
2nd Generation Algorithm
• Improved Automatic Vascular Tone Adjustment (1 min avg)
• Added fluid optimization screen enhancements
• Data Base Patients: includes high risk surgical patients
Next Generation Algorithm (SVVxtra)
• Adjusts for certain types of arrhythmias
3rd Generation Algorithm
• Adjusts for hyperdynamic patients
• Includes certain sepsis patients and liver resection
2011 2008 2006 2005
FloTrac 4.0 Algorithm update
This update to the FloTrac system algorithm has allowed for the improved measurement of rapid, but transient, changes in tone and pressure.
To better account for vaso-active drugs
To have less correlation with MAP and SVR
Nexfin
FloTrac
FT-NexGen
565 570 575 580 585 590
3.5
4
4.5
5
5.5
6
6.5
7
7.5
8
Time (minute)
CO
(L/m
in)
2011030168
Nexfin
FloTrac
FT-NexGenVaso Vaso
Simulation based on captured pressure data
Continuous, noninvasive monitoring
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History
Volume clamping invented by Jan Peňáz1, Physiocal invented by Karel Wesseling2
Product evolution over the years:
– From finger pressure to reconstructed brachial pressure3
– Blood pressure calibration using NIBP no longer needed4
– CO determination using physiological model of the circulation
The essence is to dynamically provide
equal pressures on either side of the wall of the
artery by clamping the artery to a
certain constant volume1
The ClearSight system uses a finger cuff with a
photoplethysmograph to monitor arterial
volume and an inflatable
bladder to apply the required pressure
BP measurement using Volume Clamping
The essence is to dynamically provide
equal pressures on either side of the wall of the
artery by clamping the artery to a
certain constant volume1
The ClearSight system uses a finger cuff with a
photoplethysmograph to monitor arterial volume and
an inflatable
bladder to apply the required pressure
BP measurement using Volume Clamping
1000 times each second the cuff pressure is adjusted to keep the diameter of the finger arteries constant (volume clamping)
Continuous recording of the cuff pressure results in real-time finger pressure waveform
Plethysmograph
Lightsource Lightdetector
Inflatable bladder Infrared Light
Normal situation
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Measuring arterial volume
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Applying volume clamping
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Volume clamp control loop
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Physiocal Method
Physiological calibration of the blood pressure is performed by Physiocal
Physiocal is the real-time expert system that determines the proper arterial ‘unloaded’ volume, i.e. no pressure gradient across the arterial wall2
Periodic adjustments are essential to track the unloaded volume when smooth muscle tone changes
Physiocal Method
Physiocal periodically recalibrates the system and allows accurate tracking of significant changes in the physiology
Volume change
Pressure wave Physiocal
a b d c
Pressure Waves Along Arterial Tree
100
80
60
0.4 0.8
Pre
ssu
re [m
mH
g]
Time [s]
Brachial 100
80
60
0.4 0.8
Pre
ssu
re [m
mH
g]
Time [s]
Finger 100
80
60
0.4 0.8
Pre
ssu
re [m
mH
g]
Time [s]
Radial
Brachial Pressure Reconstruction
The brachial pressure is reconstructed from the finger pressure in 2 steps3:
– Shape: Finger pressure is transformed into brachial pressure using a transfer function
– Level: Correction for brachial-finger pressure gradient
Finger pressure
Brachial pressure
Without HRS – Heart Reference Sensor
With HRS – Heart Reference Sensor
Widely used by physiologists
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Even on top of the world….
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… and beyond
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Does it work in the OR?
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Not Identical, but close, i.e.
Mean Arterial Pressure (MAP):
• Accuracy 2.2 mmHg
• Precision 6.4 mmHg
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Not Identical, but close, i.e.
Mean Arterial Pressure (MAP):
• Accuracy 2.2 mmHg
• Precision 6.4 mmHg
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Within AAMI: 5±8 mmHg
Clinical example
Edwards internal data on file. The data was collected during the BMEYE due diligence and is accurately represented in the attached slides to
the best of my knowledge - Feras Hatib, PhD, Distinguished Engineer, Discovery, Critical Care
Interesting Points: • Nexfin technology
rapidly applied &
functioning
• Good correlation with
Arterial line
• Cuff measurement less
accurate
Blood Pressure ≠ Blood Flow
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From Pressure to Flow
Blood pressure (P) and flow (Q) result from the interaction of the heart as a pump and the arterial system as its afterload (Zin)
Pulse contour methods use this close interaction in the hemodynamic version of Ohms law:
ΔP/Q = Zin
When afterload can be determined,
flow can be calculated from pressure:
Q = ΔP/Zin
Stroke volume calculation
In order to determine stroke volume and cardiac output from noninvasive continuous blood pressure, a pulse contour method based on a physiological model of the circulation is used4
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The systolic pressure-time integral ∫[P(t)-Pd]dt
140
120
80
1
100
Pre
ssu
re [m
mH
g]
Time [s]
The 3-element Windkessel model to calculate after-load using patient age, gender, height and weight
2. 1.
Cardiac output
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Non invasive opportunity for PGDT
Patients without arterial line, but at risk for complications
Examples
– Abdominal surgery
– Femur/hip fracture surgery
– Bariatric surgery
– C-section
Other: spinal anesthesia
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Su
rgic
al R
isk
ASA I-II < 65 → ASA > II & 65
ClearSight FloTrac
Basic Monitoring ClearSight
Takeaway
Post-surgical complications are:
– No exceptions
– Costly
– Increase LOS and readmission
– Affect long term survival
Hemodynamic optimization is the key to reduce post-surgical complications and requires:
– Cardiac output monitoring
– Perioperative Goal Directed Theray protocol
ClearSight and FloTrac both are well validated technologies to support hemodynamic optimization of the OR patient
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References 1. Peñáz J Photoelectric measurement of blood pressure volume and flow in the finger. In: Digest of the 10th International Conference on
Medical and Biological Engineering; Dresden; 1973; 104 2. Wesseling KH, de Wit B, van der Hoeven GMA, van Goudoever J, Settels JJ Physiocal, Calibrating Finger Vascular Physiology for
Finapres, Homeostasis 36:67-82, 1995 3. Gizdulich P1, Prentza A, Wesseling KH, Models of brachial to finger pulse wave distortion and pressure decrement, Cardiovasc Res.
1997 Mar;33(3):698-705 4. Truijen J, van Lieshout JJ, Wesselink WA, Westerhof BE, Noninvasive continuous hemodynamic monitoring, J Clin Monit Comput. 2012
Aug;26(4):267-78 5. Martina JR, Westerhof BE, van GJ, de Beaumont EM, Truijen J, Kim YS, Immink RV, Jobsis DA, Hollmann MW, Lahpor JR, et al.
Noninvasive continuous arterial blood pressure monitoring with Nexfin. Anesthesiology 2012 May;116(5):1092-103 6. Wax DB, Lin HM, Leibowitz AB, Invasive and concomitant noninvasive intraoperative blood pressure monitoring: observed differences in
measurements and associated therapeutic interventions, Anesthesiology. 2011 Nov;115(5):973-8 7. Vos JJ, Poterman M, Mooyaart EA, Weening M, Struys MM, Scheeren TW, Kalmar AF. Comparison of continuous non-invasive finger
arterial pressure monitoring with conventional intermittent automated arm arterial pressure measurement in patients under general anaesthesia. Br.J Anaesth. 2014 Jul;113(1):67-74.
8. Weiss E, Gayat E, Dumans-Nizard V, Le Guen M, Fischler M, Use of the Nexfin™ device to detect acute arterial pressure variations during anaesthesia induction, Br J Anaesth. 2014 Jul;113(1):52-60
9. Chen G, Chung E, Meng L, Alexander B, Vu T, Rinehart J, Cannesson MJ, Impact of non invasive and beat-to-beat arterial pressure monitoring on intraoperative hemodynamic management, Clin Monit Comput. 2012 Apr;26(2):133-40
10. Walsh M, Devereaux PJ, Garg AX, Kurz A, Turan A, Rodseth RN, Cywinski J, Thabane L, Sessler DI, Relationship between intraoperative mean arterial pressure and clinical outcomes after noncardiac surgery: toward an empirical definition of hypotension, Anesthesiology
11. Broch O, Renner J, Gruenewald M, Meybohm P, Schottler J, Caliebe A, Steinfath M, Malbrain M, Bein B. A comparison of the Nexfin and transcardiopulmonary thermodilution to estimate cardiac output during coronary artery surgery. Anaesthesia 2012 Apr;67(4):377-83.
12. Bubenek-Turconi SI, Craciun M, Miclea I, Perel A. Noninvasive Continuous Cardiac Output by the Nexfin Before and After Preload-Modifying Maneuvers: A Comparison with Intermittent Thermodilution Cardiac Output. Anesth Analg. 2013 Jun 11
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