AdvAnces in HemodynAmic AdvAnces in HemodynAmic monitoringmonitoring

ByBy

moHAmed A. AlimoHAmed A. Ali

security Forces HospitAl mAKKAHsecurity Forces HospitAl mAKKAH

introduction

• Hemodynamics is concerned with the forces generated by the heart and the resulting motion of blood through the cardiovascular system.

• Hemodynamic monitoring is the intermittent or continuous observation of physiological parameters related to the circulatory system that lead to early detection of the need for therapeutic interventions.

1- Intravascular volume

2-Myocardial contraction

3- heart rate

4- Vasoactivity

old equipments1. ArteriAl line

1. Real time SBP, DBP, MAP

2. Pulse pressure variation (∆PP)

• ΔPP (%) = Respiratory-induced pulse pressure variations obtained with an arterial line which indicate fluid responsiveness in mechanically ventilated patients

• AdvAntAgeAdvAntAge

– Easy setup– Real time BP monitoring– Beat to beat waveform display– Allow regular sampling of blood for lab tests

• disAdvAntAgesdisAdvAntAges

– Invasive– Risk of haematoma, distal ischemia, pseudoaneurysm

formation and infection

2. centrAl venous cAtHeter2. centrAl venous cAtHeter

– Measurement of CVP, medications infusion and modified form allow for dialysis

•AdvAntAgesAdvAntAges– Easy setup– Good for medications infusion

•disAdvAntAgesdisAdvAntAges– Cannot reflect actual RAP in most situations– Multiple complications

•Infections, thrombosis, complications on insertion, vascular erosion and bleeding

limitAtion oF cvp

Systemic venoconstrict ion

Decrease right

ventricular compliance

Obstruction of the great veins

Tricuspid regurgitat ion

Mechanical venti lat ion

3. pulmonAry ArteriAl 3. pulmonAry ArteriAl cAtHetercAtHeter

indicAtions For pAp indicAtions For pAp monitoringmonitoring

1. Shock of al l types

2. Assessment of cardiovascular function and response to therapy

3. Assessment of pulmonary status

4. Assessment of f luid requirement

5. Perioperative monitoring

clinicAl ApplicAtions oF clinicAl ApplicAtions oF pAcpAc

PAC can generate large numbers of haemodynamic variables

BAsic pArAmeters• Central venous pressure (CVP)• Pulmonary artery pressure (PAP)• Pulmonary arterial occlusion pressure (PAOP)• Cardiac output (CO)

derived pArAmeters• cardiac index (CI)• Stroke volume (SV) • Rt ventricle ejection fraction/ end diastolic volume (RVEF / RVEDV)• Systemic vascular resistance index (SVRI)• Pulmonary vascular resistance index (PVRI)• Oxygen delivery / uptake (DO2 / VO2)

cArdiogenic

• High CVP• Low CI

• High SVRI

[[

⇒ Consider inotropes / IABP

vAsogenic

• Low CVP• High CI

• Low SVRI

⇒ Consider vasopressor

pAtient witH pAtient witH HypotensionHypotension

Hypovolemic

•Low CVP•Low CI

•High SVRI

⇒ Consider f luid challenge

mixed venous mixed venous sAturAtion (svo2)sAturAtion (svo2)

• Measured in pulmonary artery blood• Marker of the balance between whole body O2

delivery (DO2) and O2 consumption (VO2) • VO2 = DO2 * (SaO2 – SvO2)• In fact, DO2 is determined by CO, Hb and SaO2.

Therefore, SvO2 affected by– CO– Hb– Arterial oxygen saturation– Tissue oxygen consumption

• normAl svo2 = 70-75%normAl svo2 = 70-75%

decreAsed svo2decreAsed svo2

• Increased consumption • Pain, Hyperthermia• Decreased delivery

• Low CO• Anemia• Hypoxia

increAsed svo2increAsed svo2

• Increased delivery• High CO• Hyperbaric O2

• Low consumption• Sedation• Paralysis• Cyanide toxicity

• AdvAntAgesAdvAntAges

– Provide lot of important haemodynamic parameters– Sampling site for SvO2

• disAdvAntAgesdisAdvAntAges

– Costly– Invasive– Multiple complications (eg. arrhythmia, catheter looping,

balloon rupture, PA injury, pulmonary infarction)

AdvAnce in hAemodynAmic AdvAnce in hAemodynAmic AssessmentAssessment

1. Modification of old equipment

2. Echocardiogram and esophageal doppler

3. Pulse contour analysis and transpulmonary thermodilution

4. Partial carbon dioxide rebreathing with application of Fick principle

5. Electrical bioimpedance

truCCOMS systemReal Time Continuous Cardiac Output Monitoring

System

• As CO increase, blood flow over the heat transfer device increase and the device require more power to keep the temp. difference Therefore provide continuous CO data

• AdvAntAgeAdvAntAge

– Continuous CO monitoring– Provision of important haemodynamic parameter

as PAC

• disAdvAntAgedisAdvAntAge

– Invasive– Costly– Complications associated with PAC use

echo• Assessment of cardiac structure, ejection

fraction and cardiac output• Based on 2D and doppler flow technique

EF (%) = [(EDV - ESV) / EDV] x 100

echo doppler echo doppler ultrAsoundultrAsound

• Measure blood flow velocity in heart and great vessels• Based on Doppler effect ⇒ “ Sound freq. increases as

sound source moves toward the observer and decreases as the sound moves away”

trAnsthorAcic echotrAnsthorAcic echo• AdvAntAges

– Fast to perform– Non invasive– Can assess valvular structure and myocardial function– No added equipment needed

• disAdvAntAges

– Difficult to get good view (esp. whose on ventilator / obese)

– Cannot provide continuous monitoring

esophAgeAl Aortic doppler esophAgeAl Aortic doppler usus

• Doppler assessment of decending aortic flow

• CO is determined by measuring aortic blood flow assuming a constant partition between caudal and cephalic blood supply areas

• Probe is smaller than that of TEE• Correlate well with CO measured

by thermodilution

Decending aorta

• AdvAntAgesAdvAntAges

– Easy placement, minimal training needed (~ 12 cases)– Provide continuous, real-time monitoring – Low incidence of iatrogenic complications– Minimal infective risk

• disAdvAntAgesdisAdvAntAges

– High cost– Poor tolerance at awake patient, so it’s used for those

intubated– Probe displacement can occur during prolonged monitoring

and patient’s turning– High inter-observer variability when measuring changes in SV

in response to fluid challenges

pulse contour pulse contour AnAlysisAnAlysis• Arterial pressure waveform is determined by

interaction of stroke volume and SVR

pulse contour pulse contour AnAlysisAnAlysis

• PiCCOPiCCO and LiDCOLiDCO are the two commonly used model on basis of PCA

• PCA involves the use of an arterially placed catheter with a pressure transducer, which can measure pressure tracings on a beat-to-beat basis

The The PiCCOPiCCO Technology uses any standard CV-line Technology uses any standard CV-line

without the need for Rt. Heart catheter (PAC) and a without the need for Rt. Heart catheter (PAC) and a

thermistor-t ipped arterial thermistor-t ipped arterial PiCCO PiCCO catheter instead of the catheter instead of the

standard arterial l ine.standard arterial l ine.

how does the phow does the p iicco-technology work?cco-technology work?

pArAmeters meAsured with the picco-technologypArAmeters meAsured with the picco-technology

thermodilution pArAmetersthermodilution pArAmeters

• Cardiac Output CO• Global End-Diastolic Volume GEDV• Intrathoracic Blood Volume ITBV• Extravascular Lung Water EVLW•Cardiac Function Index CFI• Global Ejection Fraction GEF• Pulmonary Vascular Permeability Index

PVPI*

pulse contour pArAmeterspulse contour pArAmeters

• Pulse Contour Cardiac OutputPCCO

• Arterial Blood Pressure AP• Heart Rate HR• Stroke Volume SV• Stroke Volume Variation SVV• Pulse Pressure Variation PPV• Systemic Vascular Resistance SVR• Index of Left Ventricular Contractility

dPmx*

CV

A

B

F

R

picco cAtheter picco cAtheter

1. centrAl venous line (cv)

2. pulsiocAth thermodilution cAtheter

with lumen for arterial pressure measurement

Axillary: 4F (1,4mm) 8cmBrachial: 4F (1,4mm) 22cm

Femoral: 3-5F (0,9-1,7mm) 7-20cm Radial: 4F (1,4mm) 50cm

No Right Heart C

atheter !

Bolus Injecti

on

Lungs

PiCCO Catheter e.g. in femoral artery

Transpulm. Thermodilution measurement only requires Central Venous Injection of a cold saline either at •(< 8°C) •(< 24°C) Room Temp.

ThermodiluTion parameTersThermodiluTion parameTers

Left HeartRight Heart

RA PBV

EVLW

LA LV

EVLW

RV

Tb

Inject ion

Time

∫ ⋅∆⋅⋅−=

dtTKV)T(T

COb

iibTDa

CardiaC ouTpuTCardiaC ouTpuT

Tb = Blood temperatureT i = Injectate temperatureV i = Injectate volume∫ ∆ Tb

. dt = Area under the thermodilution curveK = Correction constant, made up of specif ic weight and specif ic 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 modif iedmodif ied Stewart-Hamilton algorithm: Stewart-Hamilton algorithm:

Advanced Thermodilution Curve Advanced Thermodilution Curve AnalysisAnalysis

VolumeTriC parameTersVolumeTriC parameTers

1.1. MTt: Mean Transit MTt: Mean Transit t ime :t ime :

• Time when half of the indicator has passed the point of detection in the artery

2. 2. DSt: Down Slope DSt: Down Slope time :t ime :

• Exponential downslope time of the thermodilution curve

For the calculations of volumes

injection

recirculation

MTtt

DSt

All volumetric parameters are obtained by advanced analysis of the Thermodilution Curve:Thermodilution Curve:

RAEDV

Thermodilution curve measured

with arterial catheter

CV Bolus Injection

LAEDV LVEDVRVEDV Lungs

afTer injeCTion, The indiCaTor passes The following afTer injeCTion, The indiCaTor passes The following inTraThoraCiC ComparTmenTs:inTraThoraCiC ComparTmenTs:

• The intrathoracic compartments can be considered as a series of “mixing chambers” for the distribution of the injected indicator ( intrathoracic thermal volume).

• The largest mixing chamber in this series are the lungs, here the indicator (cold) has i ts largest distr ibution volume (largest thermal volume).

Intra thoracic Thermal Volume Intra thoracic Thermal Volume (ITTV)(ITTV)Pulmonary Pulmonary

Thermal Volume Thermal Volume (PTV)(PTV)

PBV

EVLW

EVLW

ITTV = CO * MTtTDa

PTV = CO * DStTDa

ITBV = 1.25 * GEDV

EVLW = ITTV - ITBV

GEDV = ITTV - PTV RAEDV RVEDV LAEDV LVEDV

RAEDV RVEDV LAEDV LVEDVPBV

RAEDV RVEDV LAEDV LVEDVPTV

PTV

EVLW*

EVLW*

Volume CalCulaTionsVolume CalCulaTions

pulmonary VasCular permeabiliTy indexpulmonary VasCular permeabiliTy index

Pulmonary Vascular Permeabili ty Index ( PVPI*) is the ratio of Extravascular Lung Water (EVLW*) to pulmonary blood volume (PBV). It al lows to identify the type of pulmonary oedema.

Pulmonarv Blood Volume

Hydrostatic Pulmonary Odema

Permeabil i typulmonary edema

PVPI =PBV

EVLW

Normal

Elevated

Elevated

PVPI =PBV

EVLWElevat

ed

Elevated

Normal

PVPI =PBV

EVLW

Normal

Normal

Normal

PBV

PBV

PBV Norma Lun

gExtra Vascular

Lung Water

Global Ejection Fraction (GEF)

(Transpulmonary Thermodilution)

GEF =GED

V

4 x SV

RVEF =RVEDV

SVLVEF =

LVEDV

SV

RV ejection fraction (RVEF)

(Pulm. Artery Thermodilution)

LV ejection fract ion (LVEF)

(Echocardiography)

1 2& 3

global ejeCTion fraCTion

Right Heart

Left Heart

Lungs

RAEDV

RVEDV

LVEDV

Stroke Volume SV

LAEDV

• Ejection Fraction: Stroke Volume related to End-Diastolic Volume

PBV

EVLW

EVLW

index of lefT VenTriCular ConTraCTiliTy

t [s]

P [mm Hg]

• dPmx* -- It represents left ventricular pressure velocity increase dPmx* -- It represents left ventricular pressure velocity increase and thus is a parameter of and thus is a parameter of myocardial contracti l i tymyocardial contracti l i ty

dtmax of arterial pressure dtmax of arterial pressure cc urveurve

dPdPdPmx* dPmx* ==

SVSV maxmax

SVSV minmin

SVSV meanmean

SVSV maxmax – SV – SV minminSVV =SVV =

SVSV meanmean

sTroke Volume VariaTionsTroke Volume VariaTion

• Stroke Volume Variation (SVV) represents the variat ion of stroke volume (SV) over the venti latory cycle.

• SVV is. . .

1- measured over last 30s window 2- only applicable in controlled mechanically venti lated patients with regular heart

rhythm

pulse pressure VariaTionpulse pressure VariaTion

PPPP maxmax – PP – PP minminPPV =PPV =

PPPP meanmean

PPPP maxmax

PPPP meanmean

PPPP minmin

• Pulse pressure variation (PPV) represents the variation of the pulse pressure

over the venti latory cycle.

• PPV is. . .

1- measured over last 30s window 2- only applicable in controlled mechanically venti lated patients with regular heart

rhythm

sVV and ppV – CliniCal sTudiessVV and ppV – CliniCal sTudiesS

ensi

tivi

ty

Specif icity

• Central Venous Pressure (CVP) can not predict whether volume load leads to an increase in stroke volume or not.

- - - CVP__ SVV

1

0,2

0,4

0,6

0,8

1

0,5 0

0

•SVV and PPV are excellent predictors of volume responsiveness.

DrugsVolume

What is the current s ituation?.………..…... .…..………….Cardiac

Output!

What is the preload?.……………….... .….Global End-Diastolic

Volume!

Will volume increase CO?... .………...….…….Stroke Volume

Variation!

What is the afterload?……………..…... . . . . .Systemic Vascular

Resistance!

Are the lungs sti l l dry?.. .…….……...…..…... . . .Extravascular

Lung Water!

CliniCal appliCaTion

• Global End-Diastolic Volume, GEDV and Intrathoracic Blood Volume (ITBV): have shown to be far more sensitive and specific to cardiac preload compared to the standard cardiac filling pressures CVP + PCWP as well as right ventricular enddiastolic volume.

• The striking advantage of GEDV and ITBV is that they are not adversely influenced by mechanical ventilation

• Extravascular Lung Water, EVLW* has shown to have a clear correlation to severity of ARDS, length of ventilation days, ICU-Stay and Mortality and is superior to assessment of lung odema by chest x-ray and clearly indicates fluid overload

signifiCanCesignifiCanCe

normal rangesnormal ranges

ParameterParameter RangeRange UnitUnit

CI 3.0 – 5.0 l/min/m 2

SVI 40 – 60 ml/m2

GEDI 680 – 800 ml/m 2

ITBI 850 – 1000 ml/m 2

ELWI 3.0 – 7.0 ml/kg

PVPI 1.0 – 3.0 ml/kg

SVV ≤ 10 %

PPV ≤ 10 %

GEF 25 – 35 %

CFI 4.5 – 6.5 1/min

MAP 70 – 90 mmHg

SVRI 1700 – 2400 dyn*s*cm-5*m

Decision tree for hemoDynamic / volumetric monitoring

CI (l/min/m 2)

GEDI (ml/m 2)or ITBI (ml/m 2)

ELWI* (ml/kg)(s lowly responding)

>3.0<3.0

>700>850

<700<850

>700>850

<700<850

ELWI* (ml/kg)

GEDI (ml/m 2)or ITBI (ml/m 2)

CFI (1/min)or GEF (%)

<10 >10 <10 <10 <10>10 >10 >10

V+ V+! V+!V+Cat Cat

OK!

V-

>700>850

700-800850-1000

>4.5>25

>5.5>30

>4.5>25

700-800 850-1000

Cat

>5.5>30

>700>850

700-800 850-1000

700-800 850-1000

≤10 ≤10 ≤10 ≤10

V-

V+ = volume loading (! = cautiously)V- = volume contractionCat = catecholamine / cardiovascular agents** SVV only applicable in venti lated patients without cardiac arrhythmia

>700>850

<10Optimise to SVV** (%)<10 <10 <10

RESULTS

TARGET

THERAPY

1.

2. <10 <10 <10 <10

• The LiDCO™ System provides a bolus indicator dilution method of measuring cardiac output.

• A small dose of LITHIUM CHLORIDE is injected via a central or peripheral venous line ; the resulting arterial lithium concentration-time curve is recorded by withdrawing blood past a lithium sensor attached to the patient’s existing arterial line.

• The dose of lithium needed (0.15 - 0.3 mmol for an average adult) is very small and has no known pharmacological effects

ll iiDco systemDco system

l iDco™plus monitor

The LiDCOplus System combines the LiDCO & PulseCO Systems software and provides a real-time and continuous assessment of a patient’s hemodynamic status.

PulseCO SystemIt’s a software (incorporated in the LiDCO™plus Monitor) that calculates continuous beat-to-beat cardiac output by analysis of the arterial blood pressure trace following calibration with an absolute LiDCO cardiac output value.

This method has been shown to be accurate and reliable in various clinical settings.

It has also been shown that recalibration is unnecessary for at least eight hours and more recently for 24 hours.

PULSEco system autocorrelation algorithm

The analogue arterial blood pressure trace is slaved from the conventional blood pressure monitor and undergoes a three step transformation

•Step 1: Arterial pressure transformation into a volume-time waveform.

•Step 2: Deriving nominal stroke volume and heartbeat duration.

•Step 3: Actual stroke volume via calibration with an absolute cardiac output value

liDco™plus Parameters

•Body Surface Area

•Systolic Pressure Variation & Pulse Pressure Variation

•Cardiac Index

•Oxygen Delivery & Oxygen Delivery Index

•Heart Rate & Heart Rate Variation

•Stroke Volume & Stroke Volume Index

•Stroke Volume Variation

•Intra Thoracic Blood Volume

•Systemic Vascular Resistance

•Systemic Vascular Resistance Index

aDvantages of liDco plus system

•Provides an absolute cardiac output value via a novel and proven indicator dilution technique

•Provides ITBV

•Requires no additional invasive catheters

•Safe – using non-toxic bolus dosages

•Simple and quick to set up and can be used by nursing staff

•Accurate

•Temperature non-dependent

•Less invasive monitoring

•Utilises existing peripheral or central venous and arterial lines

Picco anD liDco plus system

electrical bioimPeDance• Make use of constant electrical current stimulation for identification

of thoracic or body impedance variations induced by vascular blood flow.

• Electrodes are placed in specific areas on the neck and thorax.

• A low-grade electrical current, from 2 - 4 mA is emitted, and received by the adjacent electrodes.

• Impedance to the current flow produces a waveform.

• Through electronic evaluation of these waveforms, the timing of aortic opening and closing can be used to calculate the left ventricular ejection time and stroke volume.

electrical bioimPeDance

aDvantage:

•Non invasive•Some report same clinical accuracy as thermodilution technique.•New generation of EB device using upgraded computer technology and refined algorithms to calculate CO and get better results.

DisaDvantage:

•Reliability in critically ill patients still not very clear.•Other report poor agreement in those haemodynamically unstable and post cardiac surgery.

conclusionconclusion• Haemodynamic monitoring enable early

detection of change in patient’s conditions.

• New techniques provide reasonably good results and less invasive

• Always correlate the readings and findings with clinical pictures in order to provide the best treatment options