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ATS / ESICM / ERS / SCCM / SRLF 7th
International Consensus Conference Paris, 2006
What is the relevance of central or mixed
venous oxygen saturation ? K. Reinhart MD Dept.
of Anaesthesiology and Intensive Care
Medicine Friedrich-Schiller-University Jena,
Germany
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Tissue hypoxia, the final common pathway of the
various clinical insults that are responsible for
the development of multiple systems organ
failiure.
W. J. Sibbald
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Shock is defined as inadequate tissue oxygenation
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Which are the most appropriate cardio-respiratory
variables to detect and to monitor the course of
tissue hypoxia in the clinical setting ?
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What can we learn from physiology ?
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Conventional cardio-respiratory parameters are
of limited value for the assessment of the
adequacy of tissue oxygenation !

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The cardio-respiratory system fullfills its
physiological task by guaranteeing cellular
oxygen supply and to remove the waste products of
metabolism

Pflüger 1872
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It was fatal for the development of our
understanding of circulation, that blood flow is
relatively difficult to measure, whereas blood
pressure is easily measured This is the reason
why the blood pressure meter has gained such a
fascinating influence, although most organs do
not need pressure, but blood flow. A. Jarisch,
Kreislauffragen 1928
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The two main determinants of oxygen supply to the
tissues are arterial oxygen content and cardiac
output

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Correlation Between Arterial Pressure And Oxygen
Delivery
MAP mmHg
DO2 mlm-2min-1
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Correlation Between Heart Rate And Oxygen Delivery
HR b/min
DO2 mlm-2min-1
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Control Oxygen Consumption ml/ min/ kg
Control Cardiac Output ml/ min/ kg
Control A-V?O2 vol.
Shepard AP et al. 1973 Am.J.Physiol. 225 747
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Individual points of limb O2 uptake vs. O2
delivery over range of progressive ischemia
O2 Uptake (mlkg-1min-1 )
O2 Delivery (mlkg-1min-1 )
Reinhart K et al. (1989) Am J Physiol 257 H238
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Oxygen Debt To Pay or Not to Pay?
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Lactate (mMol/l)
SvO2 ()
p lt 0.01
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Cardic Index l/min/m2
O2 Uptake ml/min/m2
A-V Oxygen Content Difference Vols.
Donald K.W. et al. (1954) J.Clin.Invest. 33 1146
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8
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Cardic Index l/min/m2
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O2 Uptake ml/min/m2
500
400
2
300
200
100
0
2
4
6
8
10
12
14
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A-V Oxygen Content Difference Vols.
Kenneth WD et al. (1954) J.Clin.Invest. 33 1146
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The arterio-venous oxygen content difference
informs on the extent to which the compensatory
mechanisms of the cardio-respiratory system are
exhausted
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Correlation of Arterio- Venous Oxygen
Content Difference with Mixed Venous Oxygen
Saturation
avDO2 ml/dl
S?O2
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ScvO2 vs. avDO2
avDO2 ml/dl
ScvO2
Rudolph, T., et al., 1989
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Correlation of Oxygen - Supply to - Demand Ratio
with Mixed Venous Oxygen Saturation
DO2/ VO2
S?O2
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Factors that influence mixed and central venous
SO2
75
_

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What can we learn from clinical studies ?
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November 8, 2001
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Mortality
P-value
RR (95 C.I.)
Treatment
Control
0.009
0.58 (0.38-0.87)
30.5
46.5
In-hospital
0.01
0.58 (0.39 0.87)
33.3
49.2
28-day Mortality
0.03
0.67 (0.46-0.96)
44.3
56.9
60-day Mortality
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Resuscitation Endpoints
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Global Tissue Hypoxia (Cryptic Shock)Despite
Normalization of Vital Signs

• 39.8 of control vs. 5.1 of treatment group had
  global tissue hypoxia (? ScvO2 and ? lactate) at
  6 hours.

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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
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Goal oriented hemodynamic therapy in cardiac
surgical patients n 411

• Goals SvO2 gt 70 and lactate ? 2mmol/l
  from admission to the ICU and 8 hrs thereafter

goal oriented control
6 plt0,005 7
hospital stay (days)
n.s.
ICU stay
1,1 plt0,001 6,1
morbidity at hospital discharge
(Polonen et al., Anesthesia and Analgesia 2000)
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SVO2 Monitoring in Cardiac Surgery
morbidity
Polonen Anesth. Analg 2000
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Failure of Vital Signs

• 31 of 36 medical shock patients
• Resuscitated to normal MAP and CVP
• Have global tissue hypoxia (Scv02 lt 70 and
  lactate gt2 mmol/L).

Rady, AJEM, 1994
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SCVO2 Can Predict Occult Shock in CHF
Patients enrolled in decompensated CHF with
EFlt30 No difference in vital signs or clinical
category of HF between groups.
Ander Am J Card 98
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ScvO2 is superior to CVP to reflect reduced
central blood volume
(Madsen et al., Scand J Clin Lab Invest 1993)
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SCVO2 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 lt65 associated with increased injury,
  blood loss and transfusion requirements.

Scalea J Trauma 1990
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ScvO2 discriminates between patients with
clinically indistinguishable, mildly
decompensated or stable CHF
Treatment resulted in a drop in lactate by 3.65
3.65 nmol/l and an increase in ScvO2 by 32 13 .
(Ander et al. Am. J. Cardiol. 1988)
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Continuous central venous ScvO2 monitoring can
reliably indicate ROSC during CPR (n 100)

• Patients with ROSC had higher initial mean and
  maximal ScvO2.
• No ROSC in patients without ScvO2 gt 30
• A ScvO2 gt 75 was 100 predictive of ROSC.

(Rivers et al., Ann Emerg. Med. 1992)
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Complications in patients with high vs. low ScvO2
after major surgery
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Evolution of ScvO2, base excess, and lactate in
65 patients with septic shock
Parks M et al. CLINICS 200661(1)47
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Does it matter wether we measure central venous
or mixed venous oxygen saturation ?
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SsvcO2
S?O2
Lee J et al. (1972) Anaesthesiology 36 472
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SvO2 closely correlates with ScvO2
Sat
Zeit (min)
Reinhart K et al, Chest, 1989 951216-1221
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t (min)
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Zeit (min)
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All Determinations
?R.A. O2 and ?C.V. O2 - Saturation
C.V. O2 (r 0.90)
R.A. O2 (r 0.95)
?M.V. O2- Saturation
Scheinmann MM et al. 1969 Circulation 40 165
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?ScvO2 Sat
?SvO2 Sat
Reinhart K et al, Chest, 1989 951216-1221
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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 103249
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Changes in mixed venous oxygen saturation are
well matched by changes in central venous oxygen
saturation !
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Differences between SvO2 and ScvO2 in different
patient groups
Reinhart K et al., unpublished
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Differences between mixed venous and
hepato-venous O2 saturation in patients with
septic shock
SvO2 - ShO2
SvO2
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Percentage of splanchnic O2 consumption from
total body O2 consumption in septic shock
patients 60 (n34)
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In patients with severe sepsis or septic shock a
goal of 70 for central venous oxygen saturation
corresponds to a mixed venous oxygen saturation
between 60 and 65 !!!
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Does it matter wether we measure central venous
oxygen saturation continuously or discontinuously
?
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SsvcO2
S?O2
Lee J et al. (1972) Anaesthesiology 36 472
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Does it matter wether we measure central venous
oxygen saturation continuously or discontinuously
and is continuous measurement costeffective ?
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Blood gas analyses in patients with severe sepsis
and septic shock
All patients with severe sepsis or septic shock
between April 2004 and May 2005 (n221)
1 average ICU length of stay 21.5 days
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Cost assessment for central venous blood gas
analysis

• Costs of a single analysis 2.12
• Blood gas analysis 1.80
• Closing cones 0.02
• 2 x 5cc syringes 0.05
• Heparinized tube 0.25
• 163,24 /patient (estimating an average of 77
  analyses/patient)
• 6 min from begin of withdrawal until analysis is
  availableAverage time needed for measurements
  per patient 7.7 h/patient
• Cost for nurse per day approx. 135

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Blood gas analyses in patients with severe sepsis
and septic shock
All patients with severe sepsis or septic shock
between April 2004 and May 2005 (n221)
1 average ICU length of stay 21.5 days
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Limitations of mixed and central venous oxygen
saturation for the assessment of tissue
oxygenation
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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
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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)
30468
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Inadequate tissue oxygenation may exist on the
regional and organ level despite normal central
and mixed venous oxygen saturation
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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

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