1. Advances in haemodynamic
monitoring in Anaesthesia and ICU
Dr Tuong Phan
Staff Specialist Anaesthetist
Dept Anaesthesia and Pain Medicine
St Vincent’s Hospital Melbourne
2. the technology
Beyond standard monitoring
Keys to understanding
utility
Accuracy
Trending ability
utility
Clinical studies
Recommendations and summary
Minimally invasive cardiac output
Minimally invasive cardiac output
monitoring
monitoring
3. Method Proprietary device Invasive elements Parameters
Oesophageal
Doppler
CardioQTM, Deltex Medical Oesoph. Doppler
output
probe
cardiac invasive Minimally PVI CO, SV, Ftc
CardioQ PLUS OD plus arterial
line
CO, SV
Transcutaneous
Doppler
Ultrasound CO monitor,
USCOMTM
Nil CO, SV
APCO
uncalibrated
Vigileo/FloTracTM, Edwards
Lifesciences (1)
Arterial line CO, SV, SVV
LiDCO Rapide, LiDCO Ltd Arterial line CO, SV, SVV,
PPV
Finepress, Nexfin, Edwards Finger cuff CO, SV, SVV
Arterial Pressure
CO calibrated
LiDCO Plus, LiDCO Ltd (2) Arterial line CO, SV, SVV,
PPV
PiCCOplusTM, Pulsion Medical
Systems
Central Venous
catheter and
femoral arterial
line
CO, SV, ITBV,
EVLW
Plethysmography Masimo Rainbow SET Pulse CO,
Masimo Corp.
Pulse oximeter dPOP
monitoring
monitoring
Minimally invasive cardiac output
4. Method Proprietary device Invasive elements Parameters
Oesophageal
Doppler
CardioQTM, Deltex Medical Oesoph. Doppler
output
probe
cardiac invasive Minimally PVI CO, SV, Ftc
CardioQ PLUS OD plus arterial
line
CO, SV
Transcutaneous
Doppler
Ultrasound CO monitor,
USCOMTM
Nil CO, SV
APCO
uncalibrated
Vigileo/FloTracTM, Edwards
Lifesciences (1)
Arterial line CO, SV, SVV
LiDCO Rapide, LiDCO Ltd Arterial line CO, SV, SVV,
PPV
Finepress, Nexfin, Edwards Finger cuff CO, SV, SVV
Arterial Pressure
CO calibrated
LiDCO Plus, LiDCO Ltd (2) Arterial line CO, SV, SVV,
PPV
PiCCOplusTM, Pulsion Medical
Systems
Central Venous
catheter and
femoral arterial
line
CO, SV, ITBV,
EVLW
Plethysmography Masimo Rainbow SET Pulse CO,
Masimo Corp.
Pulse oximeter dPOP
monitoring
monitoring
Minimally invasive cardiac output
5. V = Df c .
2 ft cosq
the technology
Oesophageal Doppler Monitor
6. Stroke Distance
SV = VTI x Area
SV = VTI/0.7 x est desc Aortic area
DCO µ DVTI
8. Keys to
Oesophageal Doppler Monitor
• DCO µ DVTI
– Good diagnostic and trend ability
– Uncoupled from pressure entirely
• Continuously available
• Learning curve
9. Method Proprietary device Invasive elements Parameters
Oesophageal
Doppler
CardioQTM, Deltex Medical Oesoph. Doppler
output
probe
cardiac invasive Minimally PVI CO, SV, Ftc
CardioQ PLUS OD plus arterial
line
CO, SV
Transcutaneous
Doppler
Ultrasound CO monitor,
USCOMTM
Nil CO, SV
APCO
uncalibrated
Vigileo/FloTracTM, Edwards
Lifesciences (1)
Arterial line CO, SV, SVV
LiDCO Rapide, LiDCO Ltd Arterial line CO, SV, SVV,
PPV
Finepress, Nexfin, Edwards Finger cuff CO, SV, SVV
Arterial Pressure
CO calibrated
LiDCO Plus, LiDCO Ltd (2) Arterial line CO, SV, SVV,
PPV
PiCCOplusTM, Pulsion Medical
Systems
Central Venous
catheter and
femoral arterial
line
CO, SV, ITBV,
EVLW
Plethysmography Masimo Rainbow SET Pulse CO,
Masimo Corp.
Pulse oximeter dPOP
monitoring
monitoring
Minimally invasive cardiac output
10. CO-from-ABP
• MAP positively but
imperfectly correlates with
CO
– Variable changes in SVR make
MAP unreliable
– ABP waveform analysis
assumes other features are
less affected by confounders
such as Vascular resistance
• MAP is a control in Sun et al
11. CO-from-ABP
8 different
algorithms
8 different
algorithms
• All 8 methods superior to
MAP as directional qualitative
indicators of major changes in
CO-Thermodilution
• Differ drastically in
magnitude. Only one method
was superior than MAP when
comparing limits of
agreement cf CO.
Cardiac Index: 95% limits
of agreement l/min
Liljestrand*** -1.76 1.41
Corr Impedance -1.91 1.57
Pulse Pressure -2.07 1.73
Systolic Area -2.07 1.73
Sys Area with
Kouchoukos corr -2.08 1.71
AC power RMS -2.09 1.73
Diastolic decay -2.23 1.77
MAP -2.20 1.82
Herd -2.66 1.89
19. the keys to
LiDCO Plus and Rapid
• Fick principle Lithium dilution calibration
• Pulse power algorithm
– “Morphology independent”
• Arterial line required but utilises data cable
from standard monitoring system. No specific
transducer is needed
20. the technology
Vigeleo Flotrac
• Arterial pulsatility - sd of
pressure wave
• K
• sex, age, ht and wgt
• Waveform characteristics
(skewness and kurtosis)
21. the technology
Vigeleo Flotrac
• Graphic User Interface:
• “Drive screen”
• Graphic User Interface:
• “Trend screen”
23. the keys to
Vigeleo Flotrac
• Equipment: arterial line
• Flow sensor connected directly to arterial line
• Accuracy has been dependent on software
upgrades/version.
– Previously struggled with changes in compliance,
low SVR states
– version 4 being released.
24. the technology
Nexfin, aka Finepress
• Volume clamp with finger cuff
• HRS: heart reference system
– measures and corrects pressure difference btw finger
and heart
•200Hz sampling rate
• Stroke Volume – 3 element Windkessel model
• Up to 12% may have inadequate signal
28. the technology
Masimo
• Pulse oximetry
• Plethysmographic
variability index (PVI)
– It measures the dynamic
changes in perfusion index
(PI) over respiratory cycles
and calculated as follows:
– PVI = [(PImax – PImin)/PImax] x
100%.
• ΔPOP
• COHb
• Continuous Hb
29. utility
Accuracy
• Peyton and Chong
– Anesthesiology 2010
• Metaanalysis 4 CO
monitor types
• Mean bias, precision,
percentage error cf
thermodilution
• All 40%
• Limitation of BA is the
reference TD
39. Oesoph Doppler
(1) Use the Stroke Volume Index (SVI); average over 10 cycles
(2) Hypotension can be absolute or relative
(3) A large change in the SV, ie. >10%, represents the fluid
responsiveness
(4) A small change in the SV, ie <10% represents the plateau
phase and represents an optimised preload
(5) Once an optimised phase is reached, a fluid bolus should be
given if the SVI falls >10%
* The Doppler values will vary from measurement to
measurement. However, a trend over several measurements
will be more informative.
42. my observations
• Mythen and Hamilton
1995 ICM
• Exanguinate 6 healthy
volunteers
– BP drops modestly
– SV drops markedly
43. the technology
Doppler, APCO, Plethysmography
utility: Accuracy and Trending ability
Keep in mind the key parameters, their underlying assumptions and be
critical. Nevertheless estimations of stroke volume, respiratory coupled
parameters do represent a significant addition to standard monitoring eg.
Arterial pressure, urine output, CVP
utility: Clinical studies
Devices can be used to target the delivery of fluids and inotropes
recommendations and summary
They are just monitors. Outcomes will be dependent on how they
are utilised to make decisions
Minimally invasive cardiac output
Minimally invasive cardiac output
monitoring
monitoring
Editor's Notes
AACA invitation to speak
Disclosure – ANZCA and local research funds. Unrestricted use of equipment from Lidco.
No commercial interest to declare.
Bmeye, netherlands
Nexfin is based on a volume clamp system penaz 1980s
Cuff will vary to keep the arterial unloaded – position where arterial and cuff pressure are equal. As the arterial pressure rises in the mid phallanx, the cuff pressure rises in parallel.
Pressure waveform is derived. And hydrostatic pressure correction. This indirect arterial pressure is then utilised to form a reconstructed brachial pressure waveform that acts as the basis for estimated CO and SV.
Bmeye, netherlands
Nexfin is based on a volume clamp system penaz 1980s
Cuff will vary to keep the arterial unloaded – position where arterial and cuff pressure are equal. As the arterial pressure rises in the mid phallanx, the cuff pressure rises in parallel.
Pressure waveform is derived. And hydrostatic pressure correction. This indirect arterial pressure is then utilised to form a reconstructed brachial pressure waveform that acts as the basis for estimated CO and SV.
TOE: spectral display is the form that the velocities are represented on the screem. Y velocity of rbc, X time, brightness no of rbc’s.
Velocity Time Integral x CSA (measured) = SV
VTI x CSA (nomogram) = SV
Brief talk about the shapes and how they change. Don’t get too bogged down in this, except LVF is one of the shape questions.
Bmeye, netherlands
Nexfin is based on a volume clamp system penaz 1980s
Cuff will vary to keep the arterial unloaded – position where arterial and cuff pressure are equal. As the arterial pressure rises in the mid phallanx, the cuff pressure rises in parallel.
Pressure waveform is derived. And hydrostatic pressure correction. This indirect arterial pressure is then utilised to form a reconstructed brachial pressure waveform that acts as the basis for estimated CO and SV.
CCM 2009
MIT, MGH, Harvard, Macgill Beth Israel
Open source database containing Critical care physiologic parameters
MAP and CO TD
Used that to model 8 different ways of calculating CO from ABP
Some PP/RMS=Lidco, Modelflow, PICCO but only estimations of proprietary which remain black box.
All better than MAP at directional CO. Good agreement best 78% Lillestrand
Magnitude varied enormously. Only Lillestrand better than MAP
They have called on vendors to subject their devices to this database so we can test the accuracy and allow for comparison.
The difference between the maximum and the minimum systolic pressure over a single respiratory cycle, the systolic pressure variation
(SPV).
Inspiration
- blood squeezed from lung
LV preload systemic BP
intrathoracic pressure- RV preload RV stroke vol
The respiratory changes in stroke volume can be measure as the
Systolic pressure variation less accurate
Pulse Pressure variation diff btw sbp and dbp or svv apco monitor
Maguire 2011
Screened for applicability using a retrospective database.
GA, PPV, TV, PEEP, SR 39% - POP can be used
23% had arterial line AND meet criteria
Don’t take numbers to heart. As retrospective and used all comers not just those in whom CO monitoring was beig considered. Issue with low TV ventilation as well. Futier NEJM 2013 “improve study”
Lithium injected centrally or peripherally
Lithium sensor placed on ART line
Dilution curve shown on screen
Lithium injected centrally or peripherally
Lithium sensor placed on ART line
Dilution curve shown on screen
GUI graphical User interface
Enticing
Trend screen
Drive screen
Treatment algorithm
Beating heart screen
Important – marks an improvement. Same two key parameters bundled
The relationship between absolute values of (a) arterial invasive and photoplethysmographic systolic arterial pressure (220 paired data points); (b) arterial invasive and photoplethysmographic diastolic arterial pressure (220 paired data points); (c) arterial invasive and photoplethysmographic mean arterial pressure (220 paired data points); and (d) transpulmonary thermodilution and photoplethysmographic CI (120 paired data points). AI, arterial invasive; CI, cardiac index; DAP, diastolic arterial pressure; MAP, mean arterial pressure; NF, Nexfin; SAP, systolic arterial pressure; TD, transpulmonary thermodilution.
An important concept
Integration.
Into the anaesthetic monitoring modules - aside from PPV. Ev1000.
However, it means an even wider precision is now being quoted in subsequent papers as being acceptable.
All under certain conditions will obtain that no matter how bad they are. Eg. Stable ICU vs post CPB
Certainly PE does not allow discimination between the monitors
Whilst we may conclude that with TD, they are broadly the same as seen in the numerous calibatration study.
There are relatively few study that compare them head to head.
Small study we did in 2009. Grey zones represent agreement in direction. RUQ and LLQ. Difficult to demonstrate good agreement in general. But OD tracked fluid changes better. FT and li less so.
22 Cardiac patients in 2009
Larger variability in vasopressors
Lorsomradee JCVA 2009 FT 1.07 52 elective cabg
Also higher error sternotomy, phenylephrine post cpb and AI cf baseline
Inability to manage morhpological changes in arterial waveform..
In assessing FR parameters, ROC to show sensitivity – ability to show true positives. And also true negatives – not FR.
PPV at this threshold say 12% good sensitivity at it increases. And good specificity as it decreases. AUC
Conversely, CVP at any threshold has a specificity and sensitivity or 50% not much better than toss of a coin. Which I think is being a little harsh and dosent’ reflect dCVP.
ROC aren’t everything but are used for resp coupled parameters
In this review of functional haemodynamics
Main author declared interest in haemodynamic monitoring BM Eye, Pulsion.
Marik CCM 2009
Metaanalysis of “dynamic changes in arterial waveform derived variables and FR”
Highly accurate. Link btw cumulative fluid balance and poor outcomes – makes sense to give fluid in those who have demonstrated FR.
PPV/SVV dynamically reflects patients position on the starling curve
Limitations aside, there are outcome studies that utilise these monitors.
Calculation of SV. Key is correction for individual arterial compliance.
Lidco uses pulse power.
Flotrac uses Langewouter equation.
Both systems lead to diminished SV at higher pressure compared to lower pressurelevels with the same pressure curve.
Large PE 52%, if one 10% SVV the other could be 5 or 15% 95% of the time.
Urged caution in use as sole variable. Threshold probably set higher.
HUT, FL in 15 cardiac patients
Not interchangeable.
Tabulation of monitoring system and the goal of therapy
Interesting to note that the users of APCO chose not just fluid but inotrope optimisation. Speculate why? Perhaps fluid optimisation alone with APCO unlikely to yield a significant treatmet effect? Or is it a function of ICU where ease of integration of APCO cf complexity of OD?
Initialy OD but now also APCO
Utility of the devices and the parameters, needs the value of outcome studies beyond calibration/accuracy studies.
However, still limited by small studies in disparate populations. Reproducibility in unclear.
Still better than textbook anaesthesia “uo, blood pressure, assumptions to how dry the patient is, cvp, lacatate, bxs” which is devoid of rct of whatever description”
More recently, no also minimsation of respiratory coupled paramenters. Inlcuding PVI.
Interestinglys Futier decided to use dPV which is a standout rather than the standard. Not conviced about respiratory couple doppler.
Srinivasa, Taylor, Hill
No significant change in the CO (SV not mentioned) makes it unclear whether optimisation was achieved.
591 vs 297 colloid *
Some studies I suspect start with hypovolemia and as a result tdargetted therapy may have benefitted the patients
Some studies are hypervolemia.
Compare traditional approach to a new therapeutic idea in a sufficiently high number of patients
If the study group is better than the control then the study group is the future
If not then nothing changes
Problems
No easily defined control – heterogeneity of practice. Btw clinicians and hospitals and countries. Not just of fluid practice but periop practice
What is restrictive in one group is liberal in another
Whilst it is very difficult to demonstrate definitive benefit. RCT with GDT not replicating those large treatment effects seen in earlier studies. To be published soon.
What you do with those parameters may be contestable. But they tell you more about preload, stroke volume. Keep in mind the key parameters, their underlying assumptions and be critical.
The role of a second monitor
Sth that is not BP or UO
Reinforces decision making. Alters decision making.
