Could central venous oxygen
saturation be an attractive alternative to mixed venous oxygen saturation in
cardiac surgery with cardiopulmonary bypass?
L.Schmitz, D.Schmartz, I.
Huybrechts, M. Dejonckheere, C.Melot, T.Hein, L.Barvais, A.Ducart
Department of Anaesthesiology,
Hopital Erasme, ULB, Brussels, Belgium
Background and goal of study: Central venous oxygen
saturation (ScvO2) may be an interesting alternative to mixed venous oxygen
saturation (SvO2) in patients without a need of a pulmonary artery catheter
(1). The aim of this study was to evaluate the relation between SvO2 and
ScvO2 in patients scheduled for cardiac surgery with cardiopulmonary bypass
(CPB).
Materials and methods: 33 patients (10 patients
with coronary artery bypass grafting (CABG), 7 patients with valve replacement
and CABG, 16 patients with valve replacement) after written and informed
consent were included in this prospective study. A TCI remifentanil – propofol
- cisatracurium anaesthesia was used. Tip placement of the catheters in the
pulmonary artery (Swan-Ganz®, 7,5F, American Edwards Lab) and in the superior
vena cava (7F triple lumen, Arrow®) was controlled by Transesophageal
Echocardiography. Blood samples were drawn at induction (T1), 10 minutes after
CPB (T2) and after arrival in the intensive care unit (T3). The blood samples
were immediately analysed for oxygen saturation by Instrumentation Laboratory
682 CO-Oximeter. Statistical analysis was performed by linear regression,
Pearson correlations and the method of Passing and Bablok (2).
Results: Mean values ± SD, correlations (R) and confidence
limits of 95% for SvO2 and ScvO2 at T1, T2 and T3:
|
|
SvO2 (%) |
ScvO2 (%) |
R |
CI 95% |
|
T1 (n=33) |
74.5 ± 8.7 |
77.5 ± 6.8 |
0.82* |
(0.67-0.91) |
|
T2 (n=33) |
73.5 ± 6.5 |
78.5 ± 6.7 |
0.71* |
(0.49-0.85) |
|
T3 (n=33) |
68.6 ± 5.8 |
71.4 ± 7 |
0.59* |
(0.31-0.77) |
*p < 0.0003
The test of Passing Bablok shows that ScvO2
overestimates SvO2 during the 3 sample times.
Conclusions: ScvO2 can not be substituted
for SvO2 in cardiac surgery with cardiopulmonary bypass.
References
1 Rivers EP, et al. NEJM 2001; 345:1368-77.
2
Passing H. J.Clin.Chem.Clin.Biochem.1983; 21:709-20.