Haemodynamic Monitoring

Theory and Practice

2

Haemodynamic Monitoring

A. Physiological Background

B. Monitoring

C. Optimising the Cardiac Output

D. Measuring Preload

E. Introduction to PiCCO Technology

F. Practical Approach

G. Fields of Application

H. Limitations

3

Task of the circulatory system

Pflüger 1872: ”The cardio-respiratory system fulfils the physiological task of ensuring cellular oxygen supply”

Physiological Background

Uni Bonn

Goal Reached?

Assessment of oxygen supply and demand

OK

No

Yes

What is the problem?

DiagnosisTherapy

4

Physiological Background

Processes contributing to cellular oxygen supply

Aim: Optimal Tissue Oxygenation

Pulmonary gas exchange Macrocirculation Microcirculation Cell function

Direct Control Indirect

Oxygen AbsorptionLungs

Oxygen TransportationBlood

Oxygen DeliveryTissues

Oxygen Utilisation Cells / Mitochondria

Volume Catecholamines

Oxygen carriers Ventilation

5

Organ specific differences in oxygen extraction

Physiological Backgound

Oxygen delivery must always be greater than consumption!

SxO2 in %

modified from:Reinhart K in: Lewis, Pfeiffer (eds): Practical Applications of Fiberoptics in Critical Care Monitoring, Springer Verlag Berlin - Heidelberg - NewYork 1990, pp 11-23

6

Physiological Background

Dependency of Oxygen Demand on delivery

Behaviour of oxygen consumption and the oxygen extraction rate with decreasing oxygen supply

Oxygen consumption

DO2-independent area DO2- dependent area

Oxygen extraction rate

Decreasing Oxygen SupplyDO2: Oxygen Delivery

7

Central role of the mixed venous oxygen saturation

Physiological Background

Determinants of Oxygen Delivery and Consumption

Delivery DO2: DO2 = CO x Hb x 1.34 x SaO2

CO: Cardiac OutputHb: HaemoglobinSaO2: Arterial Oxygen SaturationSvO2: Mixed Venous Oxygen SaturationDO2: Oxygen DeliveryVO2: Oxygen Consumption

SaO2CO

Hb

8

Central role of mixed central venous oxygen saturation

Physiological Background

Determinants of Oxygen Delivery and Consumption

SaO2

S(c)vO2

Consumption VO2: VO2 = CO x Hb x 1.34 x (SaO2 -  SvO2)

Delivery DO2: DO2 = CO x Hb x 1.34 x SaO2

CO

Hb

Mixed Venous Saturation SvO2

SvO2

CO: Cardiac OutputHb: HaemoglobinSaO2: Arterial Oxygen SaturationSvO2: Mixed Venous Oxygen SaturationDO2: Oxygen DeliveryVO2: Oxygen Consumption

9

Oxygen delivery and its influencing factors

Physiological Background

DO2 = CaO2 x CO = Hb x 1.34 x SaO2 x CO

Transfusion

• Transfusion CO: Cardiac Output

Hb: Haemoglobin

SaO2: Arterial Oxygen Saturation

CaO2: Arterial Oxygen Content

10

Oxygen delivery and its influencing factors

Physiological Background

DO2 = CaO2 x CO = Hb x 1.34 x SaO2 x CO

Ventilation

• Transfusion• Ventilation

CO: Cardiac Output

Hb: Haemoglobin

SaO2: Arterial Oxygen Saturation

CaO2: Arterial Oxygen Content

11

Oxygen delivery and its influencing factors

Physiological Background

DO2 = CaO2 x CO = Hb x 1.34 x SaO2 x CO

VolumeCatecholamines

• Transfusion• Ventilation• Volume• Catecholamines

CO: Cardiac Output

Hb: Haemoglobin

SaO2: Arterial Oxygen Saturation

CaO2: Arterial Oxygen Content

12

Assessment of Oxygen Delivery

Physiological Background

CO: Cardiac Output; Hb: Hemoglobin; SaO2: Arterial Oxygen Saturation

CO, HbSaO2

DO2 = CO x Hb x 1.34 x SaO2

Oxygen AbsorptionLungs

Oxygen TransportBlood

Oxygen DeliveryTissues

Oxygen UtilizationCells / Mitochondria

Supply

13

Assessment of Oxygen Delivery

Physiological Background

CO, HbSaO2

Monitoring the CO, SaO2 and Hb is essential!

Oxygen AbsorptionLungs

Oxygen DeliveryTissues

Oxygen UtilizationCells / Mitochondria

Oxygen TransportBlood

CO: Cardiac Output; Hb: Haemoglobin; SaO2: Arterial Oxygen Saturation

Supply

14

Assessment of Oxygen Delivery

Physiological Background

SvO2

SaO2 CO, Hb

Monitoring the CO, SaO2 and Hb is essential!

VO2 = CO x Hb x 1.34 x (SaO2 – SvO2)

Oxygen UtilizationCells / Mitochondria

Oxygen AbsorptionLungs

Oxygen TransportBlood

Oxygen DeliveryTissues

CO: Cardiac Output; Hb: Haemoglobin; SaO2: Arterial Oxygen Saturation

Supply

Consumption

15

Assessment of Oxygen Delivery

Physiological Background

SvO2

SaO2 CO, Hb

Monitoring CO, SaO2 and Hb is essential

Monitoring the CO, SaO2 and Hb does not give information re O2-consumption!

Oxygen UtilizationCells / Mitochondria

Oxygen AbsorptionLungs

Oxygen TransportBlood

Oxygen DeliveryTissues

CO: Cardiac Output; Hb: Haemoglobin; SaO2: Arterial Oxygen Saturation

Supply

Consumption

16

Situational Factors

Balance of Oxygen Delivery and Consumption

The adequacy of CO and SvO2 is affected by many factors

Microcirculation Disturbances

Volume status Tissue Oxygen Supply

Oxygenation / Hb level

Older Age

Body weight /heightCurrent Medical HistoryPrevious Medical History

Physiological Background

General Factors

17

Physiological Background

Extended Haemodynamic Monitoring

TherapyOptimisationO2 supplyO2 consumption

Monitoring

18

Summary and Key Points

Physiological Background

• The purpose of the circulation is cellular oxygenation

• For an optimal oxygen supply at the cellular level the macro and micro-circulation as well as the pulmonary gas exchange have to be in optimal balance

• Next to CO, Hb and SaO2 is SvO2 which plays a central role in the assessment of

oxygen supply and consumption

• No single parameter provides enough information for a full assessment of oxygen supply to the tissues.