1. Advance in Hemodynamic Monitoring
By Dr H P Shum

2. Outline Introductions What we have previously – A line / CVC/ PAC
Advance techniques for haemodynamic monitoring

3. Introductions
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 pertaining to the circulatory system with a view to early detection of need for therapeutic interventions

4. 4 factors that affecting the haemodynamic conditions
Myocardial contraction and heart rate
Intravascular volume: the amount of fluid circulating in the vasculature. This can be affected by dehydration, diuresis, and volume overload due to heart or kidney failure
myocardial contraction and HR affected by exercise, stress and pharmaceutical agents or cardiac disease
Vasoactivity affected by hormone eg angiotenson II, epinephrine, norepinephrine, and vasopressin
Vasoactivity
Intravascular volume

5. Old equipments Arterial line
Real time SBP, DBP, MAP
Pulse pressure variation (PP)
ΔPP (%) = 100 × (PPmax - PPmin)/([PPmax + PPmin]/2)
>= 13% (in septic pts,) discriminate between fluid responder and non respondaer (sensitivity 94%, specificity 96%)
Am J Respir Crit Care Med 2000, 162:

6. Arterial line Advantages Disadvantages Easy setup
Real time BP monitoring
Beat to beat waveform display
Allow regular sampling of blood for lab tests
Disadvantages
Invasive
Risk of haematoma, distal ischemia, pseudoaneurysm formation and infection

7. Old equipments Central venous catheter
Measurement of CVP, medications infusion and modified form allow for dialysis

8. Limitation of CVP Obstruction of the great veins
Mechanical ventilation
Decrease right ventricular compliance
Tricuspid regurgitation
Systemic venoconstriction

9. Central venous catheter
Advantages
Easy setup
Good for medications infusion
Disadvantages
Cannot reflect actual RAP in most situations
Multiple complications
Infections, thrombosis, complications on insertion, vascular erosion and electrical shock

10. Old equipment
Pulmonary arterial catheter

11. Indications for PAP monitoring
Shock of all types
Assessment of cardiovascular function and response to therapy
Assessment of pulmonary status
Assessment of fluid requirement
Perioperative monitoring

12. Clinical applications of PAC
PAC can generate large numbers of haemodynamic variables
Central venous pressure (CVP)
Pulmonary arterial occlusion pressure (PAOP)
Cardiac output / cardiac index (CO / CI)
Stroke volume (SV)
R ventricle ejection fraction/ end diatolic volume (RVEF / RVEDV)
Systemic vascular resistance index (SVRI)
Pulmonary vascular resistance index (PVRI)
Oxygen delivery / uptake (DO2 / VO2)
=LAP = LVEDP
 By thermodilution
PAOP affected by patient body position, presence of mitral valve disease (eg MS/ MR) and L ventricular dysfx

13. Area under curve is inversely proportion to rate of blood flow in PA ( = CO)

14. Patient with hypotension
Vasogenic
Low CVP
High CI
Low SVRI
 Consider vasopressor
Hypovolemia
Low CVP
Low CI
High SVRI
 Consider fluid challenge
Cardiogenic
High CVP
Low CI
High SVRI
 Consider inotopic / IABP

15. Mixed Venous 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 determinate by CO, Hb and SaO2. Therefore, SvO2 affected by CO Hb
Arterial oxygen saturation
Tissue oxygen consumption

16. Mixed Venous Saturation SvO2
Normal SvO %
Increased SvO2
Increased delivery
high CO
hyperbaric O2
Low consumption
sedation
paralysis
cyanide toxicity
Decreased SvO2
increased consumption
pain, hyperthermia
decreased delivery
low CO
anemia
hypoxia

17. PAC Advantages Disadvantages
Provide lot of important haemodynamic parameters
Sampling site for SvO2
Disadvantages
Costly
Invasive
Multiple complications (eg arrhythmia, catheter looping, balloon rupture, PA injury, pulmonary infarction etc)
Mortality not reduced and can be even higher
Crit Care Med 2003;31:
JAMA 1996;

18. Advance in haemodynamic assessment
Modification of old equipment
Echocardiogram and esophageal doppler
Pulse contour analysis and transpulmonary thermodilution
Partial carbon dioxide rebreathing with application of Fick principle
Electrical bioimpedance

19. truCCOMS system

20. 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

21. Objective  To compare measurements of cardiac output using a new pulmonary artery catheter with those obtained using two " gold standard " methods: the periaortic transit time ultrasonic flow probe and the conventional pulmonary artery thermodilution.Design  Prospective clinical trial.Setting  Cardiac surgery operating room and surgical ICU in a university hospital.Material and methods  In the operating room, a new pulmonary artery catheter (truCCOMS system) was inserted in eight patients. A periaortic flow probe was inserted in four of them. Measurements of cardiac output obtained with the truCCOMS catheter and with the flow probe were compared at different phases of the surgical procedure. In the intensive care unit, the cardiac output displayed by the truCCOMS monitor was compared with the value obtained after bolus injection performed subsequently.Results  In the operating room (70 measurements), the coefficient of correlation between cardiac output measured by the flow probe and the truCCOMS system was r2 = 0.79, the bias was +0.11 l/min with a precision of 0.47 l/min, and limits of agreement –0.83 to +1.05 l/min. In the intensive care unit (108 measurements), the coefficient of correlation between cardiac output measured by thermodilution and the truCCOMS system was r2 = 0.56, the bias was –0.07 l/min, the precision was 0.66 l/min, and the limits of agreement were –1.39 to +1.25 l/min.Conclusion  The truCCOMS system is a reliable method of continuous cardiac output measurement in cardiac surgery patients.

22. TruCCOMS system Advantage Disadvantage Continuous CO monitoring
Provision of important haemodynamic parameter as PAC
Disadvantage
Invasive
Costly
Complications associated with PAC use

23. Transthoracic echo
Assessment of cardiac structure, ejection fraction and cardiac output
Based on 2D and doppler flow technique

27. Echo doppler ultrasound
Measure blood flow velocity in heart and great vessels
Based on Doppler effect  “ Sound freq. increases as a sound source moves toward the observer and decreases as the soure moves away”

28. For transthoracic echo
Haemodynamic assessment for SV and CO
Flow rate = CSA x flow velocity
Because flow velocity varies during ejection, individual velocities of the doppler spectrum need to be summed
Sum of velocities called velocity time integral (VTI)
SV = CSA x VTI
CSA =( LVOT Diameter /2 )2 * 
Therefore SV = D2 * * VTI
CO = SV * HR

30. Transthoracic echo Advantages Disadvantages 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

31. Transesophageal echo
CO assessment by Simpson or doppler flow technique as mentioned before
Better view and more accurate than TTE
Time consuming and require a high level of operator skills and knowledge

32. Esophageal aortic doppler US
Doppler assessment of decending aortic flow
CO determinate by measuring aortic blood flow and aortic CSA
Assuming a constant partition between caudal and cephalic blood supply areas
CSA obtain either from nomograms or by M-mode US
Probe is smaller than that for TEE
Correlate well with CO measured by thermodilution
Crit Care Med 1998 Dec;26(12):
Decending aorta

33. Normovolemia

35. Esophageal aortic doppler US
Advantages
Easy placement, minimal training needed (~ 12 cases)
provide continuous, real-time monitoring
Low incidence of iatrogenic complications
Minimal infective risk
Disadvantages
High cost
Poor tolerance at awake patient, so for those intubated
Probe displacement can occur during prolonged monitoring and patient’s turning
High interobserver variability when measuring changes in SV in response to fluid challenges

36. Pulse contour analysis
Arterial pressure waveform determinate by interaction of stroke volume and SVR

37. Pulse contour analysis
Because vascular impedance varies between patients, it had to be measured using another modality to initially calibrate the PCA system
The calibration method usually employed was arterial thermodilution or dye dilution technique
PCA involves the use of an arterially placed catheter with a pressure transducer, which can measure pressure tracings on a beat-to-beat basis
PiCCO and LiDCO are the two commonly used model

38. What is the PiCCO-Technology?
The PiCCO-Technology is a unique combination of 2 techniques
for advanced hemodynamic and volumetric management without
the necessity of a right heart catheter in most patients:
Transpulmonary Thermodilution
injection t T
CV Bolus
injection
CALIBRATION
PULSIOCATH P t
Pulse Contour Analysis

39. Parameters measured with the PiCCO-Technology
The PiCCO measures the following parameters:
Thermodilution Parameters
Cardiac Output CO
Global End-Diastolic Volume GEDV
Intrathoracic Blood Volume ITBV
Extravascular Lung Water EVLW*
Pulmonary Vascular Permeability Index PVPI*
Cardiac Function Index CFI
Global Ejection Fraction GEF
Pulse Contour Parameters
Pulse Contour Cardiac Output PCCO
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*

40. 3How does the PiCCO-Technology work?
Most of hemodynamic unstable and/or severely hypoxemic patients are
instrumented with:
Central venous line (e.g. for vasoactive agents administration…)
Arterial line (accurate monitoring of arterial pressure, blood samples…)
The PiCCO-Technology uses any standard CV-line and a thermistor-
tipped arterial PiCCO-catheter instead of the standard arterial line.

41. No Right Heart Catheter !
PiCCO Catheter
Central venous line (CV)
PULSIOCATH thermodilution catheter with lumen for arterial pressure measurement
Axillary: 4F (1,4mm) 8cm
Brachial: 4F (1,4mm) cm
Femoral: 3-5F (0,9-1,7mm) 7-20cm
Radial: 4F (1,4mm) cm CV A B R F
No Right Heart Catheter !

43. A. Thermodilution parameters
PiCCO Catheter
e.g. in femoral artery
Bolus
Injection
Transpulmonary thermodilution
measurement only requires
central venous injection of a cold
(< 8°C) or room-tempered
(< 24°C) saline bolus…
Lungs
Left Heart
Right Heart RA
PBV
EVLW* LA LV RV

44. Transpulmonary thermodilution: Cardiac Output
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:
injection
CO Calculation:
 Area under the
Thermodilution Curve Tb t
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

45. Transpulmonary thermodilution: Volumetric parameters 1
All volumetric parameters are obtained by advanced analysis of the thermodilution curve:
For the calculations of volumes…
Advanced Thermodilution Curve Analysis
Mtt: Mean Transit time
time when half of the indicator has passed the point of detection in the artery Tb
injection
recirculation
ln Tb
…and… -1 e
DSt: Down Slope time
exponential downslope time of the thermodilution curve t
MTt
DSt
…are important.

46. Transpulmonary thermodilution: Volumetric parameters 2
After injection, the indicator passes the following intrathoracic compartments:
ITTV
PTV
Thermodilution curve measured with arterial catheter
CV Bolus Injection
RVEDV
LVEDV
RAEDV
LAEDV
Lungs
Right Heart
Left Heart
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 its largest distribution volume (largest thermal volume).

47. Calculation of volumes
ITTV = CO * MTtTDa
RAEDV
RVEDV
PTV
LAEDV
LVEDV
PTV = CO * DStTDa
PTV
GEDV = ITTV - PTV
RAEDV
RVEDV
LAEDV
LVEDV
RAEDV
RVEDV
LAEDV
LVEDV
PBV
ITBV = 1.25 * GEDV
EVLW*
EVLW* = ITTV - ITBV

48. 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.
normal
EVLW*
EVLW*
PBV
PVPI* = 
Normal Lung
normal
PBV
Extra Vascular
Lung Water
Pulmonarv Blood
Volume
normal
EVLW*
elevated
EVLW*
Hydrostatic
pulmonary edema
PBV
PVPI *= 
PBV
normal
elevated
elevated
EVLW*
EVLW*
Permeability
pulmonary edema
PBV
PVPI* = 
elevated
PBV
normal

49. 4 x SV GEF = GEDV Global Ejection Fraction 1 3 & 2  Lungs Right Heart
Ejection Fraction: Stroke Volume related to End-Diastolic Volume
Lungs
Right Heart
Left Heart
EVLW*
PBV
RAEDV
RVEDV
EVLW*
LAEDV
LVEDV
Stroke Volume SV 1
& 2 3 
4 x SV
GEF =
GEDV
RVEF =
RVEDV SV
LVEF =
LVEDV SV
Global Ejection Fraction (GEF)
(transpulmonary thermodilution)
RV ejection fraction (RVEF)
(pulmonary artery thermodilution)
LV ejection fraction (LVEF)
(echocardiography)

50. Pulse Contour Analysis - Principle
P [mm Hg]
t [s]
PCCO = cal • HR •  
Systole
P(t)
SVR
+ C(p) • dP dt ( )
Shape of
pressure curve
Patient-specific calibration factor (determined by thermodilution)
Heart
rate
Area under
pressure curve
Aortic
compliance

51. Index of Left Ventricular Contractility*
dPmx* = dP/dtmax of arterial pressure curve
t [s]
P [mm Hg]
dPmx* represents left ventricular pressure velocity increase and thus is a
parameter of myocardial contractility

52. Stroke Volume Variation: Calculation
Stroke Volume Variation (SVV) represents the variation of stroke volume (SV) over the ventilatory cycle.
SVmax
SVmin
SVmean
SVmax – SVmin
SVV =
SVmean
SVV is...
... measured over last 30s window
… only applicable in controlled mechanically ventilated patients with regular heart rhythm

53. Pulse Pressure Variation: Calculation
Pulse pressure variation (PPV) represents the variation of the pulse pressure
over the ventilatory cycle.
PPmean
PPmax
PPmin
PPmax – PPmin
PPV =
PPmean
PPV is...
…measured over last 30s window
…only applicable in controlled mechanically ventilated patients with regular beat rhythm

54. CO GEDV SVV SVR EVLW* Clinical application
Drugs
Volume
What is the current situation?.………..……..………….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 still dry?...…….……...…..….Extravascular Lung Water!*

55. 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
Crit Care 4, 2000
Int Care Med 2002
Eur J Anaesth 19, 2002
Anesth Analg 95, 2002

56. Extravascular Lung Water, EVLW
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 edema by chest x-ray and clearly indicates fluid overload
Mortality as function of ELWI* in 373 critically ill ICU patients
Sakka et al , Chest 2002

57. * * Relevance of EVLW- Management Ventilation days ICU days PAC group
EVLW* group
PAC group
EVLW* group
22 days
9 days
15 days
7 days
101 patients with pulmonary edema were randomized to a pulmonary artery catheter (PAC) management group in whom fluid management decisions were guided by PCWP measurements and to an Extravascular Lung Water (EVLW*) management group using a protocol based on the bedside measurement of EVLW *.
ICU days and ventilator-days were significantly shorter in patients of the EVLW* group.
Mitchell et al, Am Rev Resp Dis 145: , 1992

58. SVV and PPV – Clinical Studies
SVV and PPV are excellent predictors of volume responsiveness. 1
Sensitivity
0,8
Central Venous Pressure (CVP) can not predict whether volume load leads to an increase in stroke volume or not.
0,6
0,4
Berkenstadt et al, Anesth Analg 92: , 2001
- - - CVP
__ SVV
0,2
0,5 1
Specificity

59. Normal ranges Parameter Range Unit CI 3.0 – 5.0 l/min/m2
SVI 40 – 60 ml/m2
GEDI 680 – 800 ml/m2
ITBI 850 – 1000 ml/m2
ELWI* 3.0 – 7.0 ml/kg
PVPI* 1.0 – 3.0
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

60. Decision tree for hemodynamic / volumetric monitoring
CI (l/min/m2)
<3.0
>3.0 R E S U L T
GEDI (ml/m2)
or ITBI (ml/m2)
<700
<850
>700
>850
<700
<850
>700
>850
ELWI* (ml/kg)
<10
>10
<10
>10
<10
>10
<10
>10 V+
V+!
Cat
Cat V+
V+! V-
Cat V- T H E R A P Y
GEDI (ml/m2)
or ITBI (ml/m2)
>700
>850
>700
>850
>700
>850 1. T A R G E 2.
Optimise to SVV** (%)
<10
<10
<10
<10
<10
<10
<10
<10
CFI (1/min)
or GEF (%)
>4.5
>25
>5.5
>30
>4.5
>25
>5.5
>30
OK!
ELWI* (ml/kg)
(slowly responding)
10
10
10
10
V+ = volume loading (! = cautiously)
V- = volume contraction
Cat = catecholamine / cardiovascular agents
** SVV only applicable in ventilated patients without cardiac arrhythmia

61. LiDCO system

62. Pulse contour analysis
Advantages
Almost continuous data of CO / SV / SV variation
Provide information of preload and EVLW
Disadvantages
Minimal invasive
Optimal arterial pulse signal required
Arrhythmia
Damping
Use of IABP

63. Partial carbon dioxide rebreathing with application of Fick principle
Fick principle is used for CO measurement
CO = VO2 / (CaO2 – CvO2) = VCO2 / (CvCO2 – CaCO2)
Based on the assumption that blood flow through the pulmonary circulation kept constant and absence of shunt
Proportional to change of CO2 elimination divided by change of ETCO2 resulting from a brief rebreathing period
The change was measured by NICO sensor

65. S = slope of CO2 dissociation curve
assume that the mixed venous co2 concentration (Cvco2) remains unchanged between baseline and rebreathing conditions
S = slope of CO2 dissociation curve

66. Partial carbon dioxide rebreathing with application of Fick principle
Advantages
Non invasive
Disadvantages
Only for those mechanically ventilated patient
Variation of ventilation modality and presence of significantly diseased lung affect the CO reading
Not continuous monitoring

67. Electrical bioimpedance
Made uses of constant electrical current stimulation for identification of thoracic or body impedance variations induced by vascular blood flow

68. Electrodes are placed in specific areas on the neck and thorax
A low-grade electrical current, from 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

69. Electrical bioimpedance
Some report same clinical accuracy as thermodilution technique
Crit Care Med 22:
Chest 111:
Crit Care Med 14:
Other report poor agreement in those haemodynamically unstable and post cardiac surgery
Crit Care Med 21:
Crit Care Med 23:
Newly generation EB device using upgraded computer technology and refined algorithms to calculate CO and get better results
Curr Opin Cardio 19:
Int Care Med 32:

70. Electrical bioimpedance
Advantage
Non invasive
Disadvantage
Reliability in critically ill patients still not very clear

71. In conclusion
Haemodynamic monitoring enable early detection of change in patient’s conditions
New techniques provide reasonably good results and less invasive
Always correlate the readings / findings with clinical pictures in order to provide the best treatment options

72. The End