haemodynamic monitoring theory and practice. 2 haemodynamic monitoring a.physiological background...
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Haemodynamic Monitoring
Theory and Practice
2
Haemodynamic Monitoring
A. Physiological Background
B. Monitoring
C. Optimising the Cardiac Output
D. Measuring Preload
E. Introduction to PiCCO Technology
F. Practical Approach
G. Fields of Application
H. Limitations
Preload
Filling Pressures
CVP / PCWP
Volumetric Preload Parameters, Volume Responsiveness and Filling Pressures
Measuring Preload
Volume Responsiveness
SVV / PPV
Volumetric
Preload parameters
GEDV / ITBV
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Kumar et al., Crit Care Med 2004;32: 691-699
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Role of the filling pressures CVP / PCWP
Correlation between Central Venous Pressure CVP and Stroke Volume
Measuring Preload
Kumar et al., Crit Care Med 2004;32: 691-699
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Correlation between Pulmonary Capillary Wedge Pressure PCWP and Stroke Volume
Measuring Preload
Role of the filling pressures CVP / PCWP
The filling pressures CVP and PCWP do not give an adequate assessment of cardiac preload.
The PCWP is, in this regard, not superior to CVP (ARDS Network, N Engl J Med 2006;354:2564-75).
Pressure is not volume!
Influencing Factors:-Ventricular compliance-Position of catheter (PAC)-Mechanical ventilation-Intra-abdominal hypertension
Role of the filling pressures CVP / PCWP
Measuring Preload
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Role of the volumetric preload parameters GEDV / ITBV
Measuring Preload
Preload
Filling Pressures
CVP / PCWP
Volume Responsiveness
SVV / PPV
Volumetric Preload parameters
GEDV / ITBV
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Total volume of blood in all 4 heart chambers
Left heartRight Heart
Measuring Preload
Pulmonary Circulation
Lungs
Body Circulation
GEDV = Global Enddiastolic Volume
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Role of the volumetric preload parameters GEDV / ITBV
Measuring Preload
GEDV shows good correlation with the stroke volume
Michard et al., Chest 2003;124(5):1900-1908
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Role of the volumetric preload parameters GEDV / ITBV
ITBV = Intrathoracic Blood Volume
Total volume of blood in all 4 heart chambers plus the pulmonary blood volume
Left heartRight heart
Measuring Preload
Pulmonary Circulation
Lungs
Body Circulation
ITBV =GEDV + PBV
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Role of the volumetric preload parameters GEDV / ITBV
Sakka et al, Intensive Care Med 2000; 26: 180-187
Measuring Preload
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ITBVTD (ml)
ITBV = 1.25 * GEDV – 28.4 [ml]
GEDV vs. ITBV in 57 Intensive Care Patients
0
1000
2000
3000
0 1000 2000 3000 GEDV (ml)
ITBV is normally 1.25 times the GEDV
Role of the volumetric preload parameters GEDV / ITBV
The static volumetric preload parameters GEDV and ITBV
Measuring Preload
• Are superior to filling pressures for assessing cardiac preload(German Sepsis Guidelines)
• Are, in contrast to cardiac filling pressures, not falsified by other pressure
influences (ventilation, intra-abdominal pressure)
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Role of the volumetric preload parameters GEDV / ITBV
Measuring Preload
Role of the dynamic volume responsiveness parameters SVV / PPV
Preload
Filling Pressures
CVP / PCWP
Volume Responsiveness
SVV / PPV
Volumetric Preload parameters
GEDV / ITBV
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Intrathoracic pressure
Venous return to left and right ventricle
Left ventricular preload
Left ventricular stroke volume
Systolic arterial blood pressure
Intrathoracic pressure
„Squeezing “ of the pulmonary blood
Left ventricular preload
Left ventricular stoke volume
Systolic arterial blood pressure
PPPPmaxmax PPPPminmin
PPPPmaxmax
PPPPminmin
Inspiration
Reuter et al., Anästhesist 2003;52: 1005-1013
Measuring Preload
Physiology of the dynamic parameters of volume responsiveness
Expiration Inspiration Expiration
Early Inspiration Late Inspiration
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Fluctuations in blood pressure during the respiration cycle
SV
PreloadV
SV
V
SV
Mechanical Ventilation
Measuring Preload
Fluctuations in stroke volume
Intrathoracic pressure fluctuationsChanges in intrathoracic blood volume
Preload changes
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Fluctuations in stroke volume throughout the respiratory cycle
Physiology of the dynamic parameters of volume responsiveness
SVSVmaxmax
SVSVminmin
SVSVmeanmean
Measuring Preload
SVV = Stroke Volume Variation
• The variation in stroke volume over the respiratory cycle
• Correlates directly with the response of the cardiac ejection to preload increase (volume responsiveness)
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mean
Role of the dynamic volume responsiveness parameters SVV / PPV
Sensitivity
- - - CVP___ SVV
SVV is more accurate for predicting volume responsiveness than CVP
Measuring Preload
Berkenstadt et al, Anesth Analg 92: 984-989, 2001
Specificity 1 0,5 0
0
0,2
0,4
0,6
0,8
1
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Role of the dynamic volume responsiveness parameters SVV / PPV
Measuring Preload
PPV = Pulse Pressure Variation
• The variation in pulse pressure amplitude over the respiration cycle • Correlates equally well as SVV for volume responsiveness
PPPPmaxmax
PPPPmeanmean
PPPPminmin
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Role of the dynamic volume responsiveness parameters SVV / PPV
Measuring Preload
A PPV threshold of 13% differentiates between responders and non-responders to volume administration
Michard et al, Am J Respir Crit Care Med 162, 2000
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Respondersn = 16
Non – Respondersn = 24
Role of the dynamic volume responsiveness parameters SVV / PPV
respiratory changes in arterial pulse pressure (%)
The dynamic volume responsiveness parameters SVV and PPV
Measuring Preload
- are good predictors of a potential increase in CO due to volume administration
- are only valid with patients who are fully ventilated and who have no cardiac arrhythmias
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Role of the dynamic volume responsiveness parameters SVV / PPV
Extravascular water content of the lung
Pulmonary circulation
Left Heart
Right Heart
Lungs
Role of extravascular lung water EVLW
Extra
EVLW = Extravascular Lung Water
Body circulation
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Role of extravascular lung water EVLW
Extra
- is useful for differentiating and quantifying lung oedema
- is, for this purpose, the only parameter available at the bedside
- functions as a warning parameter for fluid overload
The Extravascular Lung Water EVLW
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• The volumetric parameters GEDV / ITBV are superior to the filling pressures CVP / PCWP for measuring cardiac preload.
• The dynamic parameters of volume responsiveness (SVV and PPV) can predict whether CO will respond to volume administration.
• GEDV and ITBV show what the actual volume status is, whilst SVV and PPV reflect the volume responsiveness of the heart.
• For optimal control of volume therapy simultaneous monitoring of both the static preload parameters and the dynamic parameters of volume responsiveness is sensible (F. Michard, Intensive Care Med 2003;29: 1396).
Measuring Preload
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Summary and Key Points