monitorización hemodinámica - aymon.es · •mediciones de las presiones de llenado ventricular...
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1
Monitorización hemodinámica
José A. Lorente
Hospital Universitario de Getafe
CIBER de Enfermedades Respiratorias
Universidad Europea de Madrid
Respimad 2011
2
•Monitorización de la precarga
•Mediciones de las presiones de llenado ventricular
•Función cardíaca
•Relación presión/volumen en el corazón
•Presión de llenado sistémica
Monitorización hemodinámica
-5 20
0
5
Gasto
cardíaco
Precarga
Presión tele-diastólica (PAD o POAP)
CURVA DE FUNCIÓN CARDÍACA
CURVA DE FUNCIÓN CARDÍACA / RETORNO VENOSO
Función cardíaca y precarga
-5 20
0
5
Gasto
cardíaco
CURVA DE FUNCIÓN CARDÍACA
CURVA DE FUNCIÓN CARDÍACA / RETORNO VENOSO
Precarga
Presión tele-diastólica (PAD o POAP)
Función cardíaca y precarga
-5 20
0
5
Volumen
ventricular
(Precarga)
Presión tele-diastólica
(PAD o POAP)PAD
Relación normal entre el
volumen y la presión
¿Qué es la precarga?
-5 20
0
5
Volumen
ventricular
Presión tele-diastólica
(PAD o POAP)
Compliance elevada
Compliance normal
Compliance disminuída
PAD
Compliance = volumen / presión
•Estimación de la precarga (volumen) mediante la presión:
•Tres “precargas” diferentes para la misma presión!!!
•necesitamos conocer la compliance
•(la relación de P con V)
¿Qué es la precarga?
-5 20
0
5
Gasto
cardíaco
Presión tele-diastólica (PAD o POAP)
Volumen (telediastólico)
“Estiramiento”
CURVA DE FUNCIÓN CARDÍACA
CURVA DE FUNCIÓN CARDÍACA / RETORNO VENOSO
•La precarga es una “distensión”
•No es una “presión de llenado”
•No es un volumen
•Se estima por el volumen
Función cardíaca y precarga
¿Por qué conocer la precarga?
¿Qué es la precarga?
-5 20
0
5
Gasto
cardíaco
Presión tele-diastólica (PAD o POAP)
CURVA DE FUNCIÓN CARDÍACA
CURVA DE FUNCIÓN CARDÍACA / RETORNO VENOSO
Diferente respuesta (GC)
al aumentar PAD ó POAP
dependiendo de la
“precarga basal”
Función cardíaca y precarga
-5 20
0
5
Gasto
cardíaco
Presión tele-diastólica (PAD o POAP)
CURVA DE FUNCIÓN CARDÍACA
CURVA DE FUNCIÓN CARDÍACA / RETORNO VENOSO
Diferente respuesta (GC)
dependiente de la función
ventricular (relación
precarga/GC)
Función cardíaca y precarga
•PRESIONES DE LLENADO VENTRICULAR
•VD: PRESIÓN VENOSA CENTRAL → catéter venoso central
•VI: POAP → catéter de arteria pulmonar (Swan Ganz)
Presión venosa central
5 cm
5 cm debajo del
ángulo esternal:
No cambia con la
posición del paciente
Plano torácico medio
al nivel de la 5ª
costilla
(sobreestima 3 mm Hg)
Presión venosa central
Presión venosa central
Presión capilar pulmonar
PEEP=0
PEEP=15
PEEP=20
Presión capilar pulmonar
PEEP=0
PEEP=15
PEEP=20
Presión capilar pulmonar
•Determinante del llenado no es PVC sino Presión transmural
•Efecto de la Ppl sobre la PVC
•i.e. Espiración forzada
•¿Por qué se mide al final de la espiración?
Presión venosa central
Presión venosa central
Presión venosa central
¿Dónde se ha de medir?
Presión venosa central
Presión venosa central
•La PVC como indicador de la precarga
•Gold standard: reto de fluidos
•Rápido
•Aumentar PVC≥2 mm Hg
•La pendiente de la zona “dependiente”:
•5 L/min en el rango de PVC 0-10 mm Hg
•Luego: GC ≥ 300 ml por PVC cada 1 mm Hg
(y todavía se infraestima el aumento de GC)
Presión venosa central
-5 20
0
12
Gasto
cardíaco
Presión tele-diastólica (PAD o POAP)
CURVA DE FUNCIÓN CARDÍACA
-5 20
0
12
Retorno
venoso
PAD
CURVA DE RETORNO VENOSO
Presión sistémica
media
PAD
RV=(PAD-Psm)/RRV
-5 20
0
12
Gasto
cardíaco
CURVA DE FUNCIÓN CARDÍACA / RETORNO
VENOSO
Presión tele-diastólica (PVC o POAP)
PAD
-5 20
0
12
Gasto
cardíaco
Presión tele-diastólica (PVC o POAP)
CURVA DE FUNCIÓN CARDÍACA
Contractilidad
Compliance ventricular
Postcarga
0 120
0
200
Presión
VI
RELACIÓN PRESIÓN / VOLUMEN VENTRICULAR
VOLUMEN VI
8040
Llenado ventricular durante
la diástole
(relación P/V diastólica)
0 120
0
200
Presión
VI
RELACIÓN PRESIÓN / VOLUMEN VENTRICULAR
VOLUMEN VI
8040
Aumento de
presión
ventricular
al comienzo
de la sístole,
sin cambio
en el
volumen
0 120
0
200
Presión
VI
RELACIÓN PRESIÓN / VOLUMEN VENTRICULAR
VOLUMEN VI
8040
Eyección de la
sangre cuando
la PVI excede
Pao, hasta
alcanzar el
volumen tele-
sistólico
(determinado
por la
contractilidad)
0 120
0
200
Presión
VI
RELACIÓN PRESIÓN / VOLUMEN VENTRICULAR
VOLUMEN VI
8040
Relajación
isovolumétrica
0 120
0
200
Presión
VI
RELACIÓN PRESIÓN / VOLUMEN VENTRICULAR
VOLUMEN VI
8040
Emax
0 120
0
200
Presión
VI
RELACIÓN PRESIÓN / VOLUMEN VENTRICULAR
VOLUMEN VI
8040
Efecto del
aumento de
la postcarga
0 120
0
200
Presión
VI
RELACIÓN PRESIÓN / VOLUMEN VENTRICULAR
VOLUMEN VI
8040
Efecto del
aumento de la
precarga
(sin cambios en
relación P/V
diastólicos!)
0 120
0
200
Presión
VI
RELACIÓN PRESIÓN / VOLUMEN VENTRICULAR
VOLUMEN VI
8040
Efecto del
aumento de
la “rigidez”
Presión
tele-
diastóli
ca
0 120
0
200
Presión
VI
RELACIÓN PRESIÓN / VOLUMEN VENTRICULAR
VOLUMEN VI
8040
Efecto de la
disminución
de la
contractilidad
0 120
0
200
Presión
VI
RELACIÓN PRESIÓN / VOLUMEN VENTRICULAR
VOLUMEN VI
8040
Cambios
en la
sepsis
36
•Clearly, measures of central venous pressure (Pcv) as estimates of right
atrial pressure (Pra) bear little relation to cardiac preload.
•Most physicians adhere to the philosophy that the energy necessary to
cause cardiac output is due to the mechanical force of ventricular contraction.
•Most analysis of the determinants of cardiac output centralizes in the
influence of
•preload
•contractility
•afterload
•heart rate
Mean systemic filling pressure and venous return
37
•The venous system contains as much as 75% of the total blood volume, with
approximately three-fourths of it in the small veins and venules.
•It is the pressure difference between these venous capacitance vessels and
the right atrium that defines the pressure gradient for venous return.
•This venous driving pressure reflects only stressed volume and not the total
venous blood volume.
•Changes in venous vasomotor tone and blood flow distribution can markedly
alter this upstream venous pressure without any change in total blood
volume.
Mean systemic filling pressure and venous return
38
Parameters for venous return:
•mean systemic filling pressure
•right atrial pressure
•resistance to venous return
•systemic compliance
•stressed and unstressed volume
Mean systemic filling pressure and venous return
39
Mean systemic filling pressure
•A measure of effective volume status (the effective circulating blood
volume).
•Independent of cardiac function.
•Volume status and fluid responsiveness (i.e. a significant increase in cardiac
output on fluid loading) are not synonymous.
•Even hypovolemic patients can be nonresponders to fluid loading.
•Fluid responsiveness depends on the intersection of the venous return curve
and the cardiac function curve.
•Fluid expansion will lead to a greater improvement in cardiac output in a
patient with a normal cardiac function than in a patient with impaired cardiac
function.
Mean systemic filling pressure and venous return
40
Venous resistance
•The slope of the venous return curve is proportional to the reciprocal of the
resistance to venous return.
•Venous resistance can be altered in many ways:
•constriction of the conducting veins; however, unlike the arterial
side, which has thick muscular vessel walls, venoconstriction
causes only a minimal increase in Rv.
•by increased blood viscosity.
•the major mechanism by which Rv is altered is by redistribution of
blood between different vascular beds.
Mean systemic filling pressure and venous return
41
Venous resistance
•Venoconstriction of an organ decreases its unstressed blood volume,
•Its local upstream pressure transiently rises.
•Expells blood into the systemic circulation because some of the unstressed
volume is shifted to stressed volume.
•Most of the venoconstriction with change in unstressed volume occurs in the
splanchnic circulation, which has a more prominent innervation.
•As splanchnic blood flow must subsequently pass across a second
parenchymal bed, the liver, splanchnic Rv is much higher than for other
organs, and any change in splanchnic Rv has minimal effect on total Rv
•Accordingly, venoconstriction of the splanchnic circulation has a minimal
incremental effect on Rv but a significant ability to increase Pmsf.
Mean systemic filling pressure and venous return
42
Compliance, stressed and unstressed volume
•The intravascular volume can be divided into unstressed volume and
stressed volume.
•The intravascular volume that fills these vessels up to the point where
intravascular pressure starts to rise is called unstressed volume, whereas the
volume that stretches the blood vessels and causes intravascular pressure to
rise is called the stressed volume.
•Administration of vasopressors and inotropes can be used to enlarge or
reduce stressed volume.
•Vasopressors increase stressed volume by recruiting volume from the
unstressed compartment.
•The increase in venous resistance and total peripheral resistance on itself
would diminish cardiac output. The increase in cardiac output by the increase
in Pmsf dominates the negative impact on cardiac output by the increase in
arterial and venous resistance.
Mean systemic filling pressure and venous return
43
Compliance, stressed and unstressed volume
•Knowledge of the volume status is of great importance before administrating
these drugs into a critically ill patient whose endogenous adrenergic
stimulation is already maximal.
•Norepinephrine may reduce splanchnic blood pooling, increase Pmsf, Rs and
Rsys of the splanchnic circulation, but the resulting decrease in flow of the
splanchnic circulation may increase ischemia in the gut and liver.
Mean systemic filling pressure and venous return
44
Localization of Pmsf
• Pmsf reflects a physiological concept: the circulation behaves as if the
upstream pressure for venous return is Pmsf because if Pra is rapidly varied,
blood flow co-varies in a fashion consistent with that specific Pmsf.
•The localization of Pmsf reflects a lumped parameter of all the vascular
beds.
•Its position in the pooled vascular beds will shift depending on changes in
arterial and venous resistances.
•The ratio of the resistance of venous return and systemic vascular
resistance describes the location within the circulation where Pmsf exists.
•A higher ratio implies a more upstream Pmsf location.
•Pmsf usually resides in the small venous lacunae downstream from the
capillary beds.
Mean systemic filling pressure and venous return
45Jansen, Curr Op Crit Care 2010;16:231
Bedside assessment of mean systemic filling pressure
46Jansen, Curr Op Crit Care 2010;16:231
Bedside assessment of mean systemic filling pressure
47Jansen, Curr Op Crit Care 2010;16:231
Bedside assessment of mean systemic filling pressure
¡Gracias!
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52
CAMBIOS CÍCLICOS EN LA
PRESIÓN DE PULSO
Mo
nit
ori
zac
ión
de
la
pre
ca
rga
Variación de la presión de pulso
PPmax – PPminPPV =
PPmean
PPmax
PPmean
PPmin
Pulse pressure variation (PPV) represents the variation of the pulse
pressure
over the ventilatory cycle.
PPV is
•measured over last 30s window
•only applicable in controlled mechanically ventilated patients with regular beat
rhythm
Mo
nit
ori
zac
ión
de
la
pre
ca
rga
Análisis del contorno del pulso: gasto cardíaco y volumen de eyección
Mechanical
ventilation
↑↑↑Airway pressure
↑Ppl
↑Transpulmonary pressure
Capillary bed compression
(~100 ml)
↑LV filling
↑Systolic pressure
↑PP
↓RVEDV
↑RV afterload
↓RV ejection
↓Systolic pressure
↓PP
↓Venous return
↓LV filling↓LV ejection
Mo
nit
ori
zac
ión
de
la
pre
ca
rga
Variación de la presión de pulso
Mo
nit
ori
zac
ión
de
la
pre
ca
rga
Variación de la presión de pulso
Mo
nit
ori
zac
ión
de
la
pre
ca
rga
Variación de la presión de pulso
Mo
nit
ori
zac
ión
de
la
pre
ca
rga
Variación de la presión de pulso
Jardin ICM 2004;30:1047
Mo
nit
ori
zac
ión
de
la
pre
ca
rga
Variación de la presión de pulso
Jardin ICM 2004;30:1047
Mo
nit
ori
zac
ión
de
la
pre
ca
rga
Variación de la presión de pulso
Fluid overload versus hypovolemia
Jardin ICM 2004;30:1047
Mo
nit
ori
zac
ión
de
la
pre
ca
rga
Variación de la presión de pulso
RV dysfunction
Monnet et al, AJRCCM 2000;162:134
Patients on MV
with sepsis and
acute circulatory
failure
Mo
nit
ori
zac
ión
de
la
pre
ca
rga
Variación de la presión de pulso
VPP inducida
por la VM
Monnet et al, AJRCCM 2000;162:134
Mo
nit
ori
zac
ión
de
la
pre
ca
rga
Variación de la presión de pulso
VPP inducida
por la VM
VPP inducida
por la VM
Monnet et al, AJRCCM 2000;162:134
Mo
nit
ori
zac
ión
de
la
pre
ca
rga
Variación de la presión de pulso
↑EDV as a result of fluid therapy depends on the partitioning of fluid into the different vascular
compartments (with different compliances) organized in series
↑SV depends on ventricular function
↓ventricular contractility → ↓slope of EDV/SV relationship
A patient can be a non responder because of:
•↑ Venous compliance
•↓ Ventricular compliance
•Ventricular dysfunction
Variación de la presión de pulso: “pitfalls”
Falses negatives:
Small VT (i.e., ≤8 ml/kg)
MV associated with spontaneous inspirations that ↓effects on venous return
False positives:
↑RV afterload
(DPP indicates LV preload-dependence but not RV-preload dependence)
Measurement error when than manually
Variación de la presión de pulso
Monnet et al. CCM 2009
Predicting volume responsiveness by using the end-expiratory occlusion in
mechanically ventilated patients
Análisis del contorno del pulso: índice de función cardíaca
t [s]
P [mm Hg]
dPmx* = dP/dtmax of arterial pressure curve
dPmx* represents left ventricular pressure velocity increase and thus is
a parameter of myocardial contractility
Análisis del contorno del pulso: gasto cardíaco y volumen de eyección
SVmax
SVmin
SVmean
SVmax – SVminSVV =
SVmean
Stroke Volume Variation (SVV) represents the variation of stroke volume
(SV) over the
ventilatory cycle.
SVV is
•measured over last 30s window
•only applicable in controlled mechanically ventilated patients with regular heart
rhythm
Análisis del contorno del pulso: gasto cardíaco y volumen de eyección
PPmax – PPminPPV =
PPmean
PPmax
PPmean
PPmin
Pulse pressure variation (PPV) represents the variation of the pulse
pressure
over the ventilatory cycle.
PPV is
•measured over last 30s window
•only applicable in controlled mechanically ventilated patients with regular beat
rhythm
Análisis del contorno del pulso: gasto cardíaco y volumen de eyección
ANÁLISIS DEL CONTORNO
DEL PULSO
Pulse Contour Analysis
CV Bolus
injection
PULSIOCAT
H
CALIBRATION
Transpulmonary Thermodilution injection
t
T
P
t
pulse contour analysis
Bolus Injection
Lungs
PiCCO Catheter e.g. in femoral artery
Transpulmonary thermodilution
measurement only requires
central venous injection of a
cold
(< 8°C) or room-tempered
(< 24°C) saline bolus…
Thermodilution parameters
Lt HeartRt Heart
RA PBV
EVLW
* LA LV
EVLW
*
RV
* not available in the USA (p 63)
Tb injection
t
Transpulmonary thermodilution: Cardiac
Output
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
CO Calculation:
Area under the
Thermodilution Curve
After central venous injection of the indicator, the thermistor at the tip of
the arterial catheter measures the downstream temperature changes.
Cardiac output is calculated by analysis of the thermodilution curve
using a modified Stewart-Hamilton algorithm:
For correct calculation of CO, only a fraction of the total injected indicator
needs to pass the detection site. Simplified, only the change of temperature
over time is relevant.
Advanced Thermodilution Curve
Analysis
Transpulmonary thermodilution: Volumetric
parameters
Mtt: Mean Transit time
time when half of the indicator has
passed the point of detection in the
artery
DSt: Down Slope time
exponential downslope time of the
thermodilution curve
For the calculations of volumes…
ln Tb
injection
recirculation
MTt
t
e-1
DSt
Tb
All volumetric parameters are obtained by advanced analysis of the
thermodilution curve:
Transpulmonary thermodilution: Volumetric
parameters
RAEDV
Thermodilution curve
measured with arterial
catheter
CV Bolus Injection
LAEDV LVEDVRVEDV
Right
Heart
Left
Heart
Lungs
After injection, the indicator passes the following intrathoracic
compartments:
The intrathoracic compartments can be considered as a series of “mixing
chambers” for the distribution of the injected indicator (intrathoracic thermal
volume).
ITTV
PTV
The largest mixing chamber in this series are the lungs, here the
indicator (cold) has its largest distribution volume (largest thermal volume).
Transpulmonary thermodilution: Volumetric
parameters
Transpulmonary thermodilution: Newman Model
ITTV = RAEDV + RVEDV + Lungs + LAEDV + LVEDV = MTt x
Flow (CO)
PTV = Thermal Volume of the Lungs = DSt x Flow
(CO)Newman et al, Circulation 1951
RAEDV
detectioninjection
LAEDV LVEDVRVEDV
Rt Heart Lt Heart
Lungs
PTV
flow
ITTV
Multiplication of MTt (Mean Transit time) with CO results in the
complete Intrathoracic Thermal Volume (ITTV) which is the whole
needle to needle volume.
Multiplication of DSt (Downslope time) with CO yields the largest mixing
volume which is the lungs.
80
Intrathoracic Blood Volume
Intrathoracic Blood Volume
(ITBV)
is Global End-Diastolic Volume
(GEDV) + the blood volume in the
pulmonary vessels (PBV).ITBV = PBV + GEDV RVEDV LAEDVLVEDVPBVRAEDV
ITBV can be directly measured with thermal dye dilution technique (COLD System)
and has shown to be consistently 25% greater than GEDV measured by single
thermodilution technique (PiCCO).
Therefore it is possible to compute ITBV based on measurement of GEDV: ITBV =
1,25 x GEDV
ITB
VT
D (m
l)
r = 0.96
ITBV = 1.25 * GEDV – 28.4 [ml]GEDV vs. ITBV in 57 intensive care
patients
Sakka et al, Intensive Care Med 26: 180-
187, 2000
Transpulmonary thermodilution : ITBV as preload
Transpulmonary thermodilution : ITBV as preload
Transpulmonary thermodilution : ITBV as preload
Transpulmonary thermodilution: ITBV as preload
Transpulmonary thermodilution: ITBV as preload
Limitations
•Overestimates preload
•Aortic aneuyrysm
•Radial artery
•Intracardiac shunts
•Underestimates preload
•PTE
•Reduction of PBV (i.e. pneumonectomy)PBV will be 10% of ITBV and not 20%
Extravascular Lung Water*
EVLW*
EVLW*
RAEDV RVEDV LAEDV LVEDVPTV
EVLW
ITBV
ITTV
RAEDVRVEDV LAEDV LVEDVPBV
Extravascular Lung Water (EVLW*) represents the amount of water
content of the lungs and is calculated by subtraction of ITBV from ITTV.
=
Transpulmonary thermodilution: EVLW
87
Global Ejection Fraction (GEF)
(transpulmonary thermodilution)
GEF =GEDV
4 x SV
RVEF =RVEDV
SVLVEF =
LVEDV
SV
RV ejection fraction (RVEF)
(pulmonary artery thermodilution)
LV ejection fraction
(LVEF)
(echocardiography)
1 2& 3
Global Ejection Fraction
Right Heart Left HeartLungs
PBV
EVLW*
EVLW*RAEDV RVEDV LVEDV
Stroke Volume SV
LAEDV
Ejection Fraction: Stroke Volume related to End-Diastolic Volume
* not available in the USA (p 63)
Transpulmonary thermodilution
Transpulmonary thermodilution: GEF & PVPI
PBV
elevated
elevated
EVLW*
PBV
elevated
normal
PBV
normal
normal
Pulmonary Vascular Permeability Index
Pulmonary Vascular Permeability Index (PVPI) is the ratio of
Extravascular Lung Water (EVLW) to pulmonary blood volume (PBV). It
allows to identify the type of pulmonary oedema.
Pulmonarv Blood
Volume
Hydrostatic
pulmonary edema
Permeability
pulmonary edema
PVPI
=normal
PVPI* =EVLW*
elevated
PVPI
=
EVLW*
normal
PBV
EVLW*
PBV
EVLW*
PBV
EVLW*
Normal Lungs
Extra Vascular
Lung Water
Transpulmonary thermodilution: PVPI