Haemodynamic Monitoring
Theory and Practice
Introduction to the PiCCO-Technology – Function
Principles of Measurement
PiCCO Technology is a combination of transpulmonary thermodilution and pulse contour analysis
CVC
Lungs
Pulmonary Circulation
central venous
bolus injection
Right Heart
PULSIOCATH
PULSIOCATH
Left Heart
Body Circulation
PULSIOCATH
arterial thermodilution
catheter
Introduction to the PiCCO-Technology – Function
Principles of Measurement
After central venous injection the cold bolus sequentially passes through the
various intrathoracic compartments
Bolus injection
EVLW
RA
RV
PBV
LA
LV
concentration changes
over time
EVLW
(Thermodilution curve)
Right heart
Lungs
Left heart
The temperature change over time is registered by a sensor at the tip of the arterial catheter
Introduction to the PiCCO-Technology – Function
Intrathoracic Compartments (mixing chambers)
Intrathoracic Thermal Volume (ITTV)
Pulmonary Thermal
Volume (PTV)
EVLW
RA
RV
PBV
EVLW
Largest single
mixing chamber
Total of mixing chambers
LA
LV
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
Introduction to the PiCCO-Technology – Thermodilution
Calculation of the Cardiac Output
The CO is calculated by analysis of the thermodilution curve using the modified
Stewart-Hamilton algorithm
Tb
Injection
t
COTD a
(Tb - Ti) x Vi x K
=
∫ D Tb x dt
Tb = Blood temperature
Ti = Injectate temperature
Vi = Injectate volume
∫ ∆ Tb . dt = Area under the thermodilution curve
K = Correction constant, made up of specific weight and specific heat of blood and injectate
Introduction to the PiCCO-Technology – Thermodilution
Thermodilution curves
The area under the thermodilution curve is inversely proportional to the CO.
Temperature
36,5
Normal CO: 5.5l/min
37
Temperature
Time
36,5
low CO: 1.9l/min
37
Temperature
Time
36,5
High CO: 19l/min
37
5
10
Time
Introduction to the PiCCO –Technology – Thermodilution
Transpulmonary vs. Pulmonary Artery Thermodilution
Transpulmonary TD (PiCCO)
Pulmonary Artery TD (PAC)
Aorta
Pulmonary
Circulation
PA
Lungs
central venous
bolus injection
LA
RA
Right Heart
Left heart
PULSIOCATH
arterial thermodilution catheter
RV
LV
Body Circulation
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
Extended analysis of the thermodilution curve
From the characteristics of the thermodilution curve it is possible to determine certain time
parameters
Tb
Injection
Recirculation
In Tb
e-1
MTt
DSt
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
Tb = blood temperature; lnTb = logarithmic blood temperature; t = time
t
Introduction to the PiCCO-Technology – Thermodilution
Calculation of ITTV and PTV
By using the time parameters from the thermodilution curve and the CO ITTV and
PTV can be calculated
Tb
Injection
Recirculation
In Tb
e-1
MTt
DSt
t
Intrathoracic Thermal Volume
Pulmonary Thermal Volume
ITTV = MTt x CO
PTV = Dst x CO
Einführung in die PiCCO-Technologie – Thermodilution
Calculation of ITTV and PTV
Intrathoracic Thermal Volume (ITTV)
Pulmonary Thermal
Volume (PTV)
EVLW
RA
RV
PBV
EVLW
PTV = Dst x CO
ITTV = MTt x CO
LA
LV
Introduction to the PiCCO –Technology – Thermodilution
Volumetric preload parameters – GEDV
Global End-diastolic Volume (GEDV)
ITTV
PTV
EVLW
RA
RV
PBV
LA
LV
EVLW
GEDV
GEDV is the difference between intrathoracic and pulmonary thermal volumes
Introduction to the PiCCO –Technology – Thermodilution
Volumetric preload parameters – ITBV
Intrathoracic Blood Volume (ITBV)
GEDV
EVLW
RA
RV
PBV
PBV
LA
LV
EVLW
ITBV
ITBV is the total of the Global End-Diastolic Volume and the blood volume in
the pulmonary vessels (PBV)
Introduction to the PiCCO-Technology – Thermodilution
Volumetric preload parameters – ITBV
ITBV is calculated from the GEDV by the PiCCO Technology
Intrathoracic Blood Volume (ITBV)
ITBVTD (ml)
3000
2000
1000
0
ITBV = 1.25 * GEDV – 28.4 [ml]
0
1000
GEDV vs. ITBV in 57 Intensive Care Patients
Sakka et al, Intensive Care Med 26: 180-187, 2000
2000
3000 GEDV (ml)
Introduction to the PiCCO-Technology – Function
Intrathoracic Compartments (mixing chambers)
Intrathoracic Thermal Volume (ITTV)
Pulmonary Thermal
Volume (PTV)
EVLW
RA
RV
PBV
EVLW
Largest single
mixing chamber
Total of mixing chambers
LA
LV
Introduction to the PiCCO –Technology – Extravascular Lung Water
Calculation of Extravascular Lung Water (EVLW)
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.
Introduction to the PiCCO –Technology – Extravascular Lung Water
Validation of Extravascular Lung Water
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
Gravimetry
Dye dilution
ELWI by PiCCO
ELWIST (ml/kg)
Y = 1.03x + 2.49
40
25
n = 209
r = 0.96
20
30
15
20
10
10
0
R = 0,97
P < 0,001
0
10
20
30
ELWI by gravimetry
Katzenelson et al,Crit Care Med 32 (7), 2004
5
0
0
5
10
15
20
25
ELWITD (ml/kg)
Sakka et al, Intensive Care Med 26: 180-187, 2000
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
Introduction to the PiCCO-Technology – Pulse contour analysis
Calibration of the Pulse Contour Analysis
The pulse contour analysis is calibrated through the transpulmonary thermodilution
and is a beat to beat real time analysis of the arterial pressure curve
Transpulmonary Thermodilution
Pulse Contour Analysis
Injection
COTPD
HR
T = blood temperature
t = time
P = blood pressure
= SVTD
Introduction to the PiCCO-Technology – Pulse contour analysis
Parameters of Pulse Contour Analysis
Cardiac Output
dP
 P(t)
PCCO = cal • HR • (
+ C(p) •
) dt
 SVR
dt
Systole
Patient- specific calibration
factor (determined by thermodilution)
Heart rate
Area under the
pressure curve
Aortic compliance
Shape of the pressure
curve
Introduction to the PiCCO-Technology – Pulse Contour Analysis
Parameters of Pulse Contour Analysis
Dynamic parameters of volume responsiveness – Stroke Volume Variation
SVmax
SVmin
SVmean
SVV =
SVmax – SVmin
SVmean
The Stroke Volume Variation is the variation in stroke volume over the ventilatory cycle,
over the previous 30 second period.
measur
Introduction to the PiCCO-Technology – Pulse Contour Analysis
Parameters of Pulse Contour Analysis
Dynamic parameters of volume responsiveness – Pulse Pressure Variation
PPmax
PPmin
PPmean
PPV =
PPmax – PPmin
PPmean
The pulse pressure variation is the variation in pulse pressure over the ventilatory cycle,
measured over the previous 30 second period.
Introduction to the PiCCO-Technology – Pulse contour analysis
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