haemodynamic monitoring theory and practice. picco technology is a combination of transpulmonary...
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Haemodynamic Monitoring
Theory and Practice
PiCCO Technology is a combination of transpulmonary thermodilution and pulse contour analysis
Principles of Measurement
Left HeartRight Heart
Pulmonary Circulation
Lungs
Body CirculationPULSIOCATHPULSIOCATH
CVC
PULSIOCATH arterial thermodilution catheter
central venous bolus injection
Introduction to the PiCCO-Technology – Function
Bolus injection
concentration changes over time(Thermodilution curve)
After central venous injection the cold bolus sequentially passes through the various intrathoracic compartments
The temperature change over time is registered by a sensor at the tip of the arterial catheter
Introduction to the PiCCO-Technology – Function
Left heartRight heart Lungs
RA RV LA LVPBV
EVLW
EVLW
Principles of Measurement
Intrathoracic Compartments (mixing chambers)
Introduction to the PiCCO-Technology – Function
Pulmonary Thermal Volume (PTV)
Intrathoracic Thermal Volume (ITTV)
Total of mixing chambers
RA RV LA LVPBV
EVLW
EVLW
Largest single mixing chamber
Haemodynamic Monitoring
E. Introduction to PiCCO Technology
1. Principles of function
2. Thermodilution
3. Pulse contour analysis
4. Contractility parameters
5. Afterload parameters
6. Extravascular Lung Water
7. Pulmonary Permeability
Tb x dt
(Tb - Ti) x Vi x
K
Tb
Injection
t
∫ =COTD a
Tb = Blood temperatureTi = Injectate temperatureVi = Injectate volume∫ ∆ Tb
. dt = Area under the thermodilution curve
K = Correction constant, made up of specific weight and specific heat of blood and injectate
The CO is calculated by analysis of the thermodilution curve using the modified Stewart-Hamilton algorithm
Calculation of the Cardiac Output
Introduction to the PiCCO-Technology – Thermodilution
The area under the thermodilution curve is inversely proportional to the CO.
36,5
37
5 10
Thermodilution curves
Normal CO: 5.5l/min
Introduction to the PiCCO-Technology – Thermodilution
36,5
37
36,5
37
Time
low CO: 1.9l/min
High CO: 19l/min
Time
Time
Temperature
Temperature
Temperature
Transpulmonary vs. Pulmonary Artery Thermodilution
Left heartRight Heart
Pulmonary Circulation
Lungs
Body Circulation
PULSIOCATH arterial thermo-dilution catheter
central venous bolus injection RA
RV
PA
LA
LV
Aorta
Transpulmonary TD (PiCCO) Pulmonary Artery TD (PAC)
In both procedures only part of the injected indicator passes the thermistor.
Nonetheless the determination of CO is correct, as it is not the amount of the detected indicator but the difference in temperature over time that is relevant!
Introduction to the PiCCO –Technology – Thermodilution
MTt: Mean Transit time the mean time required for the indicator to reach the detection point
DSt: Down Slope time the exponential downslope time of the thermodilution curve
Recirculation
t
e-1
Tb
From the characteristics of the thermodilution curve it is possible to determine certain time parameters
Extended analysis of the thermodilution curve
Introduction to the PiCCO-Technology – Thermodilution
Injection
In Tb
MTt DSt
Tb = blood temperature; lnTb = logarithmic blood temperature; t = time
Pulmonary Thermal Volume
PTV = Dst x CO
By using the time parameters from the thermodilution curve and the CO ITTV and PTV can be calculated
Calculation of ITTV and PTV
Introduction to the PiCCO-Technology – Thermodilution
Recirculation
t
e-1
Tb
Injection
In Tb
Intrathoracic Thermal Volume
ITTV = MTt x CO
MTt DSt
Pulmonary Thermal Volume (PTV)
Intrathoracic Thermal Volume (ITTV)
Calculation of ITTV and PTV
Einführung in die PiCCO-Technologie – Thermodilution
ITTV = MTt x CO
PTV = Dst x CO
RA RV LA LVPBV
EVLW
EVLW
GEDV is the difference between intrathoracic and pulmonary thermal volumes
Global End-diastolic Volume (GEDV)
Volumetric preload parameters – GEDV
RA RV LA LVPBV
EVLW
EVLW
ITTV
GEDV
PTV
Introduction to the PiCCO –Technology – Thermodilution
Volumetric preload parameters – ITBV
Intrathoracic Blood Volume (ITBV)
GEDV
ITBV
PBVRA RV LA LVPBV
EVLW
EVLW
Introduction to the PiCCO –Technology – Thermodilution
ITBV is the total of the Global End-Diastolic Volume and the blood volume in the pulmonary vessels (PBV)
ITBVTD (ml)
ITBV = 1.25 * GEDV – 28.4 [ml]
GEDV vs. ITBV in 57 Intensive Care Patients
IIntrantratthoracic horacic BBlood lood VVolume (olume (ITBVITBV))
Volumetric preload parameters – ITBV
Introduction to the PiCCO-Technology – Thermodilution
ITBV is calculated from the GEDV by the PiCCO Technology
0
1000
2000
3000
0 1000 2000 3000 GEDV (ml)
Sakka et al, Intensive Care Med 26: 180-187, 2000
Intrathoracic Compartments (mixing chambers)
Introduction to the PiCCO-Technology – Function
Pulmonary Thermal Volume (PTV)
Intrathoracic Thermal Volume (ITTV)
Total of mixing chambers
RA RV LA LVPBV
EVLW
EVLW
Largest single mixing chamber
ITTV
– ITBV
= EVLW
The Extravascular Lung Water is the difference between the intrathoracic thermal volume and the intrathoracic blood volume. It represents the amount of water in the lungs outside the blood vessels.
Calculation of Extravascular Lung Water (EVLW)
Introduction to the PiCCO –Technology – Extravascular Lung Water
Katzenelson et al,Crit Care Med 32 (7), 2004 Sakka et al, Intensive Care Med 26: 180-187, 2000
Gravimetry Dye dilution
EVLW from the PiCCO technology has been shown to have a good correlation with the measurement of extravascular lung water via the gravimetry and dye dilution reference methods
Validation of Extravascular Lung Water
n = 209r = 0.96
ELWI by gravimetry
ELWI by PiCCO
R = 0,97P < 0,001
Y = 1.03x + 2.49
0
10
20
30
20 30
40
10
ELWITD (ml/kg)
0
5
10
20
15 25
25
50 100 20
15
ELWIST (ml/kg)
Introduction to the PiCCO –Technology – Extravascular Lung Water
Haemodynamic Monitoring
E. Introduction to PiCCO Technology
1. Principles of function
2. Thermodilution
3. Pulse contour analysis
4. Contractility parameters
5. Afterload parameters
6. Extravascular Lung Water
7. Pulmonary Permeability
Transpulmonary Thermodilution
The pulse contour analysis is calibrated through the transpulmonary thermodilution and is a beat to beat real time analysis of the arterial pressure curve
Calibration of the Pulse Contour Analysis
Introduction to the PiCCO-Technology – Pulse contour analysis
Injection
Pulse Contour Analysis
T = blood temperature t = timeP = blood pressure
COCOTPDTPD= SV= SVTDTD
HRHR
PCCO = cal • HR •P(t)SVR
+ C(p) •dPdt
( ) dt
Cardiac Output
Patient- specific calibration factor (determined by thermodilution)
Heart rate Area under the pressure curve
Shape of the pressure curve
Aortic compliance
Systole
Introduction to the PiCCO-Technology – Pulse contour analysis
Parameters of Pulse Contour Analysis
SVSVmaxmax – SV – SVminminSVV =SVV =
SVSVmeanmean
SVSVmaxmax
SVSVminmin
SVSVmeanmean
The Stroke Volume Variation is the variation in stroke volume over the ventilatory cycle, measured over the previous 30 second period.
Parameters of Pulse Contour Analysis
Introduction to the PiCCO-Technology – Pulse Contour Analysis
Dynamic parameters of volume responsiveness – Stroke Volume Variation
PPPPmaxmax – PP – PPminminPPV =PPV =
PPPPmeanmean
The pulse pressure variation is the variation in pulse pressure over the ventilatory cycle, measured over the previous 30 second period.
Parameters of Pulse Contour Analysis
Introduction to the PiCCO-Technology – Pulse Contour Analysis
Dynamic parameters of volume responsiveness – Pulse Pressure Variation
PPPPmaxmax
PPPPmeanmean
PPPPminmin
Summary pulse contour analysis - CO and volume responsiveness
• The PiCCO technology pulse contour analysis is calibrated by transpulmonary thermodilution
• PiCCO technology analyses the arterial pressure curve beat by beat thereby providing real time parameters
• Besides cardiac output, the dynamic parameters of volume responsiveness SVV (stroke volume variation) and PPV (pulse pressure variation) are determined continuously
Introduction to the PiCCO-Technology – Pulse contour analysis