Transpulmonary Thermodilution Technology
TPTD
Theory and Practice
Haemodynamic Monitoring with TPTD
1.
Principles of function
2.
Thermodilution
3.
Contractility parameters
4.
Extravascular lung water
5.
Pulmonary permeability
Central venous catheter
• jugular
• subclavian
Thermodilution arterial catheter
• femoral
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
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
1.
Principles of function
2.
Thermodilution
3.
Contractility parameters
4.
Extravascular Lung Water
5.
Pulmonary Permeability
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 =
k x Vi x (Tb - Ti)
AUC
Tb = Blood temperature
Ti = Injectate temperature
Vi = Injectate volume
AUC = Area under the thermodilution curve
K = Correction constant, made up of specific weight and specific heat of blood and injectate
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
CARDIAC OUTPUT, l/min
PiCCO
VolumeView
12
11
10
9
8
7
6
5
4
BASE
Bendjelid et al. ESICM 2010
DOBU
BASE
HYPO
BASE
HYPER
ALI
Transpulmonary vs. Pulmonary Artery Thermodilution
Transpulmonary TD (EV 1000)
Pulmonary Artery TD (PAC)
Aorta
Pulmonary
Circulation
PA
Lungs
central venous
bolus injection
LA
RA
Right Heart
Left heart
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!
Validation of the Transpulmonary Thermodilution
Comparison with Pulmonary Artery Thermodilution
n (Pts / Measurements)
bias ±SD(l/min)
r
Friedman Z et al., Eur J Anaest, 2002
17/102
-0,04 ± 0,41
0,95
Della Rocca G et al., Eur J Anaest 14, 2002
60/180
0,13 ± 0,52
0,93
Holm C et al., Burns 27, 2001
23/218
0,32 ± 0,29
0.98
Bindels AJGH et al., Crit Care 4, 2000
45/283
0,49 ± 0,45
0,95
Sakka SG et al., Intensive Care Med 25, 1999
37/449
0,68 ± 0,62
0,97
Gödje O et al., Chest 113 (4), 1998
30/150
0,16 ± 0,31
0,96
9/27
0,19 ± 0,21
-/-
Pauli C. et al., Intensive Care Med 28, 2002
18/54
0,03 ± 0,17
0,98
Tibby S. et al., Intensive Care Med 23, 1997
24/120
0,03 ± 0,24
0,99
McLuckie A. et a., Acta Paediatr 85, 1996
Comparison with the Fick Method
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
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
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
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
The new Volume View method to assess GEDV
S1
S2
GEDV = CO x MTt x f (S2/S1)
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
Summary and Key Points - Thermodilution
• TPTD Technology is a less invasive method for monitoring the volume
status and cardiovascular function.
• Transpulmonary thermodilution allows calculation of various volumetric
parameters.
• The CO is calculated from the shape of the thermodilution curve.
• The volumetric parameters of cardiac preload can be calculated
through advanced analysis of the thermodilution curve.
• For the thermodilution measurement only a fraction of the total
injected indicator needs to pass the detection site, as it is only the
change in temperature over time that is relevant.
Haemodynamic Monitoring
1.
Principles of function
2.
Thermodilution
3.
Contractility parameters
4.
Extravascular Lung Water
5.
Pulmonary Permeability
Contractility
Contractility is a measure for the performance of the heart muscle
Contractility parameters of TPTD technique:
- dPmx (maximum rate of the increase in pressure)
- GEF (Global Ejection Fraction)
- CFI (Cardiac Function Index)
kg
Contractility parameter from the pulse contour analysis
dPmx = maximum velocity of pressure increase
The contractility parameter dPmx represents the maximum velocity
of left ventricular pressure increase.
Contractility parameter from the pulse contour analysis
dPmx = maximum velocity of pressure increase
n = 220
y = -120 + (0,8* x)
r = 0,82
p < 0,001
femoral dP/max 2000
[mmHg/s]
1500
1000
500
0
0
500
1000
1500
2000
LV dP/dtmax
[mmHg/s]
de Hert et al., JCardioThor&VascAnes 2006
dPmx was shown to correlate well with direct measurement of velocity of left
ventricular pressure increase in 70 cardiac surgery patients
Assessment of cardiac function by EJECTION FRACTION
RVEF =
SV
SV
RVEDV
LVEDV
RV ejection fraction (RVEF)
(pulmonary artery thermodilution)
LV ejection fraction (LVEF)
(echocardiography)
SV
GEDV / 4
Global Ejection Fraction (GEF)
(transpulmonary thermodilution)
= GEF
= LVEF
Contractility parameters from the thermodilution measurement
GEF = Global Ejection Fraction
LA
RA
LV
GEF =
4 x SV
GEDV
RV
• is calculated as 4 times the stroke volume divided by the global end-diastolic
volume
• reflects both left and right ventricular contractility
Contractility parameters from the thermodilution measurement
GEF = Global Ejection Fraction
sensitivity
1
15
18
0,8
8
12
16
19
10
5
0,6
20
0,4
-20
22
-10
10
20
D FAC, %
-5
0,2
-10
0
0
0,2
0,4
0,6
0,8
1 specifity
-15
r=076, p<0,0001
n=47
D GEF, %
Combes et al, Intensive Care Med 30, 2004
Comparison of the GEF with the gold standard TEE measured contractility in
patients without right heart failure
Contractility parameters from the thermodilution measurement
CFI = Cardiac Function Index
CFI =
CI
GEDVI
• is the CI divided by global end-diastolic volume index
• is - similar to the GEF – a parameter of both left and right ventricular
contractility
Combes et al. Intensive Care Med 2004
Jabot et al. Crit Care Med 2009
Jabot et al. Crit Care Med 2009
What do we need for management of acute circulatory failure ?
Acute circulatory failure
Low cardiac output
Hypotension
CO 
AP 
Vasoplegia
Low SVR
Inadequate preload
Low GEDV
Depressed contractility
Low GEF/CFI
Haemodynamic Monitoring
1.
Principles of function
2.
Thermodilution
3.
Contractility parameters
4.
Extravascular Lung Water
5.
Pulmonary Permeability
EVLW What for ?
diagnostic
prognostic
therapeutic
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.
Animal validation against gravimetry
Katzenelson et al. Crit Care Med 2004 (Dog)
Mondejar et al. J Crit Care 2003 (Pig)
Kirov et al. Crit Care 2005 (Sheep)
Validation of Extravascular Lung Water
EVLW from the TPTD technique has been shown to have a good correlation with
the measurement of extravascular lung water via the gravimetry and dye dilution
reference methods
ELWI
Dye dilution
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
EVLW as a quantifier of lung edema
High extravascular lung water is not reliably identified by blood gas analysis
ELWI (ml/kg)
30
20
10
0
0
50
150
250
350
450
PaO2 /FiO2
Boeck J, J Surg Res 1990; 254-265
550
Eisenberg et al. Am Rev Respir Dis 1987
EVLW as a quantifier of lung oedema
Chest x ray – does not reliably quantify pulmonary oedema and is difficult to judge,
particularly in critically ill patients
D radiographic score
r = 0.1
p > 0.05
80
60
40
20
0
-15
-10
10
-20
-40
-60
-80
Halperin et al, 1985, Chest 88: 649
15
D ELWI
EVLW as a quantifier of lung oedema
ELWI = 19 ml/kg
ELWI = 14 ml/kg
Extravascular lung
water index
(ELWI)
normal range:
3 – 7 ml/kg
ELWI = 7 ml/kg
ELWI = 8 ml/kg
Relevance of EVLW Assessment
The amount of extravascular lung water is a predictor for mortality in the intensive
care patient
Mortality (%)
Mortality(%)
100
n = 81
90
80
70
70
60
60
50
n = 373
40
50
30
40
20
30
20
*p = 0.002
80
10
0
4 - 6 6 - 8 8 - 10 10 - 12 - 16 16 - > 20
12
20
ELWI (ml/kg)
Sturm J in: Lewis, Pfeiffer (eds): Practical Applications of Fiberoptics in
Critical Care Monitoring, Springer Verlag Berlin - Heidelberg - NewYork
1990, pp 129-139
0
0
<7
n = 45
7 - 14
n = 174
Sakka et al , Chest 2002
14 - 21
n = 100
> 21
n = 54
ELWI (ml/kg)
Relevance of EVLW Assessment
Volume management guided by EVLW can significantly reduce time on ventilation and
ICU length of stay in critically ill patients, when compared to PCWP oriented therapy,
Ventilation Days
* p ≤ 0,05
n = 101
Intensive Care
days
* p ≤ 0,05
22 days
9 days
15 days
7 days
PAC Group
EVLW Group
PAC Group
EVLW Group
Mitchell et al, Am Rev Resp Dis 145: 990-998, 1992
Goepfert et al. Intensive Care Med 2006
Haemodynamic Monitoring
1.
Principles of function
2.
Thermodilution
3.
Contractility parameters
4.
Extravascular Lung Water
5.
Pulmonary Permeability
Differentiating Lung Oedema
PVPI = Pulmonary Vascular Permeability Index
PVPI =
EVLW
EVLW
PBV
PBV
• is the ratio of Extravascular Lung Water to Pulmonary Blood Volume
• is a measure of the permeability of the lung vessels and as such can
classify the type of lung oedema (hydrostatic vs. permeability caused)
Pulmonary Vascular Permeability Index = PVPI
Hydrostatic
pulmonary edema
Permeability
pulmonary edema
EVLW
PBV
PVPI = EVLW/PBV
>>>>
PVPI = EVLW/PBV
Classification of Lung Oedema with the PVPI
Difference between the PVPI with hydrostatic and permeability lung oedema:
Lung oedema
hydrostatic
permeability
PBV
PBV
EVLW
EVLW
EVLW
EVLW
PBV
PBV
PVPI normal (1-3)
PVPI raised (>3)
Validation of the PVPI
PVPI can differentiate between a pneumonia caused and a cardiac failure caused
lung oedema.
PVPI
4
3
2
Cardiac insufficiency
Pneumonia
16 patients with congestive heart failure and acquired pneumonia. In both
groups EVLW was 16 ml/kg.
Benedikz et al ESICM 2003, Abstract 60
Monnet et al. Intensive Care Med 2007
Clinical Relevance of the Pulmonary Vascular Permeability Index
EVLWI answers the question:
How much water is in the lungs?
PVPI answers the question:
Why is it there?
and can therefore give valuable aid for therapy guidance!
Summary and Key Points
• EVLW as a valid measure for the extravascular water content of the lungs is
the only parameter for quantifying lung oedema available at the bedside.
• Blood gas analysis and chest x-ray do not reliably detect and measure lung
edema
• EVLW is a predictor for mortality in intensive care patients
• The Pulmonary Vascular Permeability Index can differentiate between
hydrostatic and a permeability caused lung oedema