What is the relevance of central or mixed venousoxygen saturation ?

K. Reinhart MDDept. of Anaesthesiology and Intensive Care Medicine

Friedrich-Schiller-University Jena, Germany

ATS / ESICM / ERS /

SCCM / SRLF7th International Consensus

Conference

Paris, 2006

Shock is defined Shock is defined as inadequate as inadequate

tissuetissueoxygenationoxygenation

Which are the Which are the most appropriate most appropriate

cardio-cardio-respiratory respiratory

variables to variables to detect and to detect and to monitor the monitor the

course of tissue course of tissue hypoxia in the hypoxia in the

clinical setting ?clinical setting ?

What can we What can we learn from learn from

physiology ?physiology ?

Conventional cardio-Conventional cardio-respiratory parameters are respiratory parameters are

of limited value for the of limited value for the assessment of the adequacy assessment of the adequacy

of tissue oxygenation !of tissue oxygenation !

The cardio-respiratory system The cardio-respiratory system fullfills its physiological task by fullfills its physiological task by

guaranteeing cellular oxygen guaranteeing cellular oxygen supply and to remove the waste supply and to remove the waste

products of metabolismproducts of metabolism

Pflüger 1872

It was fatal for the development of our It was fatal for the development of our understanding of circulation, that blood understanding of circulation, that blood flow is relatively difficult to measure, flow is relatively difficult to measure, whereas blood pressure is easily whereas blood pressure is easily measured: measured: This is the reason why the blood This is the reason why the blood pressure meter has gained such a pressure meter has gained such a fascinating influence, although most fascinating influence, although most organs do not need pressure, but blood organs do not need pressure, but blood flow. flow.

AA. Jarisch, “Kreislauffragen“ 1928. Jarisch, “Kreislauffragen“ 1928

The two main The two main determinants of determinants of

oxygen supply to the oxygen supply to the tissues are arterial tissues are arterial oxygen content and oxygen content and

cardiac outputcardiac output

DO2 ml*m-2*min-1

100 300 500 700 900 1100

n= 123230

60

90

120

150

180

MA

P m

mH

gCorrelation Between Arterial Correlation Between Arterial

Pressure And Oxygen DeliveryPressure And Oxygen Delivery

DO2 ml*m-2*min-1

100 300 500 700 900 1100

n= 123630

60

90

120

150

180

HR

b/m

inCorrelation Between Heart Rate Correlation Between Heart Rate

And Oxygen DeliveryAnd Oxygen Delivery

Shepard AP et al. 1973 Am.J.Physiol. 225: 747

0 2 4 6 8 10 1260

100

140

180

220

260

Control A-VO2 vol.%

Control Cardiac Output ml/ min/ kg

Control Oxygen Consumption

ml/ min/ kg

12

10864

Reinhart K et al. (1989) Am J Physiol 257:

H238

Individual points of limb OIndividual points of limb O22 uptake vs. O uptake vs. O22

delivery over range of progressive ischemiadelivery over range of progressive ischemiaO

2 U

ptak

e (m

l*kg

-1*m

in-1

)

O2 Delivery (ml*kg-1*min-1 )

2

0

4

6

8

2520151050

Oxygen Debt: To Pay or Not to Pay?

SvO2 (%)**p < 0.01**p < 0.01

3.5

3.0

2.5

2.0

1.5

1.0

50 60 70 80 90

****

n=9n=9 n=29n=29n=77n=77

n=150n=150n=148n=148

n=110n=110n=27n=27

Lact

ate

(mM

ol/l)

Car

dic

Inde

x l/m

in/m

2

A-V Oxygen Content Difference Vols. %

O2 U

ptak

e m

l/min

/m2

4

6

8

10

12

2 4 6 8 10 12

300

500

700

900

1100

Donald K.W. et al. (1954) J.Clin.Invest. 33: 1146

Kenneth WD et al. (1954) J.Clin.Invest. 33: 1146

Car

dic

Inde

x l/m

in/m

2

A-V Oxygen Content Difference Vols. %

O2 U

ptak

e m

l/min

/m2

0

2

4

6

8

2 4 6 8 10 12 14 16

100

200

300

400

500

The arterio-venous The arterio-venous oxygen content difference oxygen content difference informs on the extent to informs on the extent to which the compensatory which the compensatory

mechanisms of the cardio-mechanisms of the cardio-respiratory system are respiratory system are

exhaustedexhausted

25 40 55 70 85 100

9.3

8.2

7.1

6.0

4.9

3.8

2.7

1.6

0.5

r= -0.864

y= 12.7 -0.12x

n= 1191

SO2 %

avD

O2 m

l/dl

Correlation of Arterio- Venous Oxygen ContentCorrelation of Arterio- Venous Oxygen ContentDifference with Mixed Venous Oxygen Difference with Mixed Venous Oxygen

SaturationSaturation

Rudolph, T., et al., 1989

ScvOScvO22 vs. avDO vs. avDO22

30 40 50 60 70 80 90 100

8.0

7.0

6.0

5.0

4.0

3.0

2.0

1.0

0

r= -0.707

n= 447

avDO2= 11.4 -0.1*ScvO2

ScvO2 %

avD

O2 m

l/dl

Correlation of Oxygen - Supply to - Demand Correlation of Oxygen - Supply to - Demand Ratio with Mixed Venous Oxygen SaturationRatio with Mixed Venous Oxygen Saturation

SO2 %

DO

2/

VO

2

25 705540 85 1001.0

2.8

4.6

6.4

8.2

10.0

r= 0.906

y= -9.58 + 0.19*x

n= 1149

75%

Factors that influence mixed and central venous Factors that influence mixed and central venous SOSO22

VO2 DO2 DO2 VO2 Stress

Pain

Hyperthermia

Shivering

PaO2

Hb

Cardiac output

PaO2

Hb

Cardiac output

Hypothermia

Anesthesia

_+

What can we What can we learn from learn from

clinical studies ? clinical studies ?

November 8, 2001

MortalityMortality

0.0090.58 (0.38-0.87)30.546.5In-hospital

P-value RR (95% C.I.) TreatmentControl

0.030.67 (0.46-0.96)44.356.960-day Mortality

0.010.58 (0.39 – 0.87)33.349.228-day Mortality

Resuscitation Endpoints

0 12 24 36 48 60 723 6

40

50

60

70

80 * *

* ** *

Sc

vO

2

0 12 24 36 48 60 723 6

0

2

4

6

8*

** *

La

cta

te

* ControlTreatment

0 12 24 36 48 60 723 6

-2

2

6

10*

**

*

*

***

Ba

se

De

fic

it

0 12 24 36 48 60 723 6

7.25

7.30

7.35

7.40

7.45

*

* *

*pH

Hours

Global Tissue Hypoxia (Cryptic Shock)Global Tissue Hypoxia (Cryptic Shock)Despite Normalization of Vital SignsDespite Normalization of Vital Signs

• 39.8% of control vs. 5.1% of treatment

group had global tissue hypoxia ( ScvO2

and lactate) at 6 hours.

SVO2 Monitoring in Cardiac Surgery

• Polonen et al have studied a cohort 403 of cardiac surgical patients

– The control group received standard care whilst in the protocol group, SvO2 was maintained above 70% and lactate below 2mmol/l with fluid and inotropes

– The study was undertaken in the immediate 8 hour post-operative period

Polonen Anesth. Analg 2000

Goal oriented hemodynamic therapy in cardiac surgical patients n = 411

Goals: SvO2 > 70% and lactate 2mmol/l from admission to the ICU and 8 hrs thereafter

6 p<0,005 7hospital stay (days)

1,1% p<0,001 6,1%morbidity at hospital

discharge

n.s.ICU stay

goal oriented control

(Polonen et al., Anesthesia and Analgesia 2000)

Failure of Vital SignsFailure of Vital Signs

• 31 of 36 medical shock patients:

– Resuscitated to normal MAP and CVP

– Have global tissue hypoxia (Scv02 < 70%

and lactate >2 mmol/L).

Rady, AJEM, 1994

SCVO2 Can Predict Occult Shock in CHF

0

10

20

30

40

50

60

SCVO2 %

Control Low Lactate High Lactate

Patients enrolled in decompensated CHF with EF<30%No difference in vital signs or clinical category of HF between groups.

Ander Am J Card 98

ScvOScvO22 is superior to CVP to reflect is superior to CVP to reflect

reduced central blood volumereduced central blood volume

(Madsen et al., Scand J Clin Lab Invest 1993)

before

blood loss

after

blood loss

CVPmm Hg

3 *(6 – 1)

1(5 – -3)

ScvO2 %

75 **(69 – 78)

60(49 – 67)

SSCVCVOO22 Monitoring in Trauma Monitoring in Trauma

• 26 consecutive patients with injury suggestive of blood loss.

• HR, BP, Urine output, CVP and SCVO2 measured.

• Blood loss estimated.• SCVO2 most sensitive indicator blood loss• SCVO2 <65% associated with increased injury,

blood loss and transfusion requirements.

Scalea J Trauma 1990

Continuous central venous ScvOContinuous central venous ScvO22 monitoring monitoring

can reliably indicate ROSC during CPRcan reliably indicate ROSC during CPR (n = 100) (n = 100)

Patients with ROSC had higher initial mean and

maximal ScvO2.

No ROSC in patients without ScvO2 > 30%

A ScvO2 > 75% was 100% predictive of ROSC.

(Rivers et al., Ann Emerg. Med. 1992)

Complications in patients with high vs. low ScvO2 after major surgery

Evolution of ScvO2, base excess, and lactate in 65 patients with septic

shock

Parks M et al. CLINICS 2006;61(1):47

Does it matter wether we Does it matter wether we measure central venous measure central venous or mixed venous oxygen or mixed venous oxygen

saturation ?saturation ?

Lee J et al. (1972) Anaesthesiology 36:

472

% S

svc O

2

% SO2

100

80

60

40

20

0 20 40 60 80 100

r= 0.73

r= 0.88

Shock

Normal

Reinhart K et al, Reinhart K et al, Chest, 1989; 95:1216-1221Chest, 1989; 95:1216-1221

SvOSvO22 closely correlates with ScvO closely correlates with ScvO22

Zeit (min)Zeit (min)

% S

at%

Sat

8080

6060

4040

2020

00

303000 6060 9090 120120 150150 180180 210210 240240

NormoxieNormoxie BlutungBlutung Volumentherapie (HAES)Volumentherapie (HAES) BlutungBlutung

Hyp

oxi

eH

ypo

xie

No

rmo

xie

No

rmo

xie

Hyp

ero

xie

Hyp

ero

xie

Gemischt-venösGemischt-venös

Zentral-venösZentral-venös

t (min)

%

20 30 40 50 60100

SvO2

50

60

70

80

90

100

40

ScvO2

Zeit (min)

%

0 10 20 30 40

40

50

60

70

80

90

100

ScvO2

SvO2

All DeterminationsAll Determinations

Scheinmann MM et al. 1969 Circulation 40: 165

M.V. O2- % Saturation

R.A

. O

2 an

d C

.V.

O2 -

%S

atur

atio

n

R.A. O2 (r= 0.95)

C.V. O2 (r= 0.90)

SvO2 % Sat

Scv

O2 %

Sat

80

60

40

20

0

-20

-40

-60

-80-80 -60 -40 -20 0 20 40 60 80

r= 0.9761

p< 0.001

n= 131

Reinhart K et al, Reinhart K et al, Chest, 1989; 95:1216-1221Chest, 1989; 95:1216-1221

Changes in SvO2 and ScvO2 in general anesthesia during

neurosurgery

Conclusion: Despite some large differences between absolute values, in patients with varying hemodynamic situations, the trend in ScvO2 may be used as a surrogate variable for the trend in SvO2.

Dueck MH et al. Anesthesiology 2005; 103:249

Changes in mixed venous Changes in mixed venous oxygen saturation are well oxygen saturation are well

matched by changes in matched by changes in central venous oxygen central venous oxygen

saturation !saturation !

Differences between SvODifferences between SvO22 and ScvO and ScvO2 2 in in

different patient groupsdifferent patient groups

SO2n = number of measurements

high risk surgical

n = 18 7,25 % 220 313

septic shock

n = 11 7,90 % 148 534

severe head injury

n = 3 10,7 % 26 281

Reinhart K et al., unpublished

SvO

2 -

ShO

2 [

%]

SvO2 [%]

Differences between mixed venous and Differences between mixed venous and hepatohepato--venous Ovenous O22 saturation in patients saturation in patients

with septic shockwith septic shock

-10

0

10

20

30

40

60 62 64 66 68 70 72 74 76 78 80 82

Normalbereich

Percentage of splanchnic O2 consumption

from total body O2 consumption

in septic shock patients

60% (n=34)

In patients with In patients with severe sepsis or severe sepsis or

septic shock a goal of septic shock a goal of 70% for central 70% for central venous oxygen venous oxygen

saturation saturation corresponds to a corresponds to a

mixed venous oxygen mixed venous oxygen saturation between saturation between

60 and 65% !!!60 and 65% !!!

Does it matter wether we Does it matter wether we measure central venous measure central venous

oxygen saturation oxygen saturation continuously or continuously or

discontinuously ?discontinuously ?

Blood gas analyses in patients with severe sepsis and septic shock

Central venous blood gas analysis

Total amount all patients; all days

16,936

Average amount during ICU stay (range)

76.9 (1-393)

Average amount per patient and day1

3.5

1: average ICU length of stay 21.5 days

All patients with severe sepsis or septic shock between April 2004 and May 2005 (n=221)

Average costs per patient (Euro)

approx. 300,00

Limitations of mixed and Limitations of mixed and central venous oxygen central venous oxygen

saturation for the saturation for the assessment of tissue assessment of tissue

oxygenation oxygenation

pHirCO2

Hepatic venous blood flow(splanchnic blood flow)

ICG-clearanceMEGX-test

Hepatic venous O2-saturation

Transcutaneous liver near infrared spectroscopy (TOI) in 20 children during surgical hemorrhage

• TOILiver provided a better trend monitor of central venous oxygen saturation than gastric intramucosal pH.

• Because of its limited sensitivity and specificity to indicate deterioration of SvO2, liver tissue oxygenation measured by transcutaneous NIRS does not provide additional practical information for clinical management.

Weiss M et al. Pediatric Anesthesia 2004; 14: 989

Correlation between central venous oxygen saturation and near-infrared spectroscopic

cerebral oxygenation (cTOI) in 43 critically ill children

Nagdyman N. et al. Intensive Care Med (2004) 30:468

Inadequate tissue Inadequate tissue oxygenation may exist on oxygenation may exist on

the regional and organ the regional and organ level despite normal level despite normal

central and mixed venous central and mixed venous oxygen saturation oxygen saturation

Summary• ScvO2 and SvO2 are superior to conventional hemodynamic monitoring

parameters in the assessment of the adequacy of global tissue oxygenation

• Continuous monitoring of ScvO2 and SvO2 in the framework of hemodynamic

goals and treatment algorithms have resulted im improved patient outcome

• ScvO2 closely parallels SvO2 saturation

• In patients with shock ScvO2 is 7 – 10% (mean) higher than SvO2

• These differences between ScvO2 and SvO2 saturation result from changes

in the regional blood flow and oxygen supply/demand ratio

• Normal or high ScvO2 and SvO2 do not rule out tissue hypoxia on the organ

or regional level