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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.
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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 PULSIOCATH arterial thermodilution catheter Right Heart Left Heart PULSIOCATH PULSIOCATH Body Circulation
EVLW RA RV PBV LA LV EVLW 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 concentration changes over time (Thermodilution curve) Lungs Right heart Left heart The temperature change over time is registered by a sensor at the tip of the arterial catheter
EVLW RA RV PBV LA LV EVLW Introduction to the PiCCO-Technology – Function Intrathoracic Compartments (mixing chambers) Intrathoracic Thermal Volume (ITTV) Pulmonary Thermal Volume (PTV) Largest single mixing chamber Total of mixing chambers
Haemodynamic Monitoring E. Introduction to PiCCO Technology • Principles of function • Thermodilution • Pulse contour analysis • Contractility parameters • Afterload parameters • Extravascular Lung Water • 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 (Tb - Ti) x Vi xK COTD a = Tbx dt D ∫ 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 10 5 Time
Introduction to the PiCCO –Technology – Thermodilution Transpulmonary vs. Pulmonary Artery Thermodilution Transpulmonary TD (PiCCO) Pulmonary Artery TD (PAC) Aorta PA Pulmonary Circulation Lungs LA central venous bolus injection RA LV RV PULSIOCATH arterial thermo-dilution catheter Right Heart Left heart 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 t 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
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 Pulmonary Thermal Volume PTV = Dst x CO Intrathoracic Thermal Volume ITTV = MTt x CO
EVLW RA RV PBV LA LV EVLW Einführung in die PiCCO-Technologie – Thermodilution Calculation of ITTV and PTV Intrathoracic Thermal Volume (ITTV) Pulmonary Thermal Volume (PTV) PTV = Dst x CO ITTV = MTt x CO
EVLW RA RV PBV LA LV EVLW Introduction to the PiCCO –Technology – Thermodilution Volumetric preload parameters – GEDV Global End-diastolic Volume (GEDV) ITTV PTV GEDV GEDV is the difference between intrathoracic and pulmonary thermal volumes
EVLW RA RV PBV LA LV EVLW Introduction to the PiCCO –Technology – Thermodilution Volumetric preload parameters – ITBV Intrathoracic Blood Volume (ITBV) GEDV PBV ITBV ITBV is the total of the Global End-Diastolic Volume and the blood volume in the pulmonary vessels (PBV)
3000 2000 1000 0 0 1000 2000 3000 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) ITBV = 1.25 * GEDV – 28.4 [ml] GEDV(ml) GEDV vs. ITBV in 57 Intensive Care Patients Sakka et al, Intensive Care Med 26: 180-187, 2000
EVLW RA RV PBV LA LV EVLW Introduction to the PiCCO-Technology – Function Intrathoracic Compartments (mixing chambers) Intrathoracic Thermal Volume (ITTV) Pulmonary Thermal Volume (PTV) Largest single mixing chamber Total of mixing chambers
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 20 30 n = 209 r = 0.96 15 20 10 10 5 R = 0,97 P < 0,001 0 0 0 10 20 30 0 5 10 15 20 25 ELWI by gravimetry ELWITD (ml/kg) Sakka et al, Intensive Care Med 26: 180-187, 2000 Katzenelson et al,Crit Care Med 32 (7), 2004
Haemodynamic Monitoring E. Introduction to PiCCO Technology • Principles of function • Thermodilution • Pulse contour analysis • Contractility parameters • Afterload parameters • Extravascular Lung Water • 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 = SVTD HR T = blood temperature t = time P = blood pressure
Patient- specific calibration factor (determined by thermodilution) 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 Cardiac Output P(t) dP ( PCCO = cal • HR • + C(p) • ) dt SVR dt Systole Heart rate
SVmax SVmin SVmean Introduction to the PiCCO-Technology – Pulse Contour Analysis Parameters of Pulse Contour Analysis Dynamic parameters of volume responsiveness – Stroke Volume Variation SVmax – SVmin SVV = SVmean The Stroke Volume Variation is the variation in stroke volume over the ventilatory cycle, measured over the previous 30 second period.
Introduction to the PiCCO-Technology – Pulse Contour Analysis Parameters of Pulse Contour Analysis Dynamic parameters of volume responsiveness – Pulse Pressure Variation PPmax PPmin PPmean PPmax – PPmin PPV = 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