What is the future of haemodynamic monitoring

1
What is the future of haemodynamic monitoring?

• Steven M. Hollenberg, MD
• Professor of Medicine
• Robert Wood Johnson Medical School/UMDNJ
• Director, Coronary Care Unit
• Cooper University Hospital, Camden NJ

2
Prediction is very difficult, especially about
the future.
3
The only way to predict the future is to invent
it.
4
The future of hemodynamic monitoring

• New technologies
• New hemodynamic parameters
• New methods of analysis
• Methods of evaluation

5
New technologies

• Implantable monitors

6
New technologies

• Miniaturization
• Imagers
• X-ray
• MRI
• Ultrasound
• Sensors, effectors, and transmitters
• Surgical instruments
• Analyzers
• Optical sensors

7
New technologies

• Noninvasive methods of evaluation
• Echocardiography
• Myocardial contrast visualization, perfusion
• Tissue Doppler
• Strain rate imaging
• Hand-held devices
• Bioimpedance
• Magnetic resonance imaging

8
New hemodynamic parameters

• Microcirculatory flow and density
• Cardiac power

9
(No Transcript)
10
Cooper MARS Mission

• To study the alterations of the sublingual
  microcirculatory network in humans with severe
  sepsis undergoing early goal-directed
  resuscitation
• To determine if microcirculatory flow velocity
  and perfused vessel density correlate with
  conventional hemodynamic parameters in patients
  with severe sepsis

11
Microcirculatory flow in Sepsis
12
Cardiac Power
Cardiac Power Output watt Mean Arterial
Pressure x Cardiac Output / 451
Fincke R, et al. J Am Coll Cardiol 2006 44340
13
New methods of analysis

• Reductionist approach
• Take things apart
• Simple rules will yield simple results
• Output is proportional to input
• Engineering paradigms for hemodynamics
• Heart as a pump
• Electrical analogy with impedance as resistance

14
Hemodynamic waveforms

• Time series measurements
• Smooth, large-scale continuous signal
• Discontinuous, small-scale, erratic disruptions
  (noise)
• Filter out the noise
• Describe the average state toward which
  homeostatic mechanisms are heading

15
Biology is a complex system

• Body is complex, open and dynamic
• System a group of independent but interconnected
  elements that function together to comprise a
  unified whole.
• Emergent properties properties of the system
  as a whole that cannot be predicted from
  individual components
• Fluctuations around the average are not just
  noise, but convey information
• Healthy variability nonstationary, nonlinear,
  and multiscaled
• Disease is characterized not by loss of
  regularity but by loss of complexity

16
Nonlinear analysis

• Can in theory be automated by computer
• Changes in frequency spectrum components of
  variability
• Breakdowns of fractal scaling with disease
• Challenges
• Some of the measures are nonintuitive
• Volume of data to be captured is daunting
• Artifacts are a real problem
• Paucity of therapeutic interventions directed at
  nonlinear measures

17
Evaluation of new technologies

• Monitoring tools would not be expected to improve
  outcome unless tied to an effective therapeutic
  strategy prompted by data they provide
• Hemodynamic measures are not used in isolation
  but in clinical context
• Thus, a single hemodynamic variable taken alone
  is rarely a good predictor of the response to an
  intervention
• Implications for trial design

18
New evaluation paradigms

• Polar ideas that no approach can be adopted
  without a pivotal RCT and that since no approach
  can be rigorously tested that theory is enough
  are equally constricting
• Consensus conferences
• Uniform definitions
• Uniform processes of evaluation
• Managing differences of opinion

19
Evaluating existing evidence and planning new
trials

• Surrogate endpoints
• Skepticism is appropriate, but there may be no
  alternative
• Tradeoff between power and feasibility
• How should surrogates be developed and validated?
• Translation of measures of proven efficacy in
  clinical trials into effective strategies when
  applied broadly

20
The way forward

• We make our own future
• We need active engagement with the evaluation and
  implementation of new concepts and technologies
• New hemodynamic parameters
• New ways of measurement
• New methods of analysis