ABSTRACT
Introduction: Mixed venous oxygen saturation [SvO2], is an invasive monitoring technique that reflects the balance between systemic oxygen transport and tissue oxygen consumption. Whereas tissue oxygen saturation [StO2] is a noninvasive technique that allows early detection of tissue hypoperfusion. The purpose of this study is to evaluate StO2 in patients undergoing elective coronary surgery: single cardiopulmonary bypass [CPB], and to find a correlation between StO2 and SvO2
Material and Methods: All patients scheduled for elective coronary surgery from May to July 2013, were included in the study. The anesthetic management and hemodynamic monitoring were the same. The following parameters: BP, HR, CI, SaO2, SvO2, StO2 at the eminence thenar, Hb and deltaPCO2 were monitored at the following times: T1: before anesthesia induction, T2: after induction, T3: 30 min after the beginning of CPB, T4: after the weaning from CBP, T5: H 12, at D1, D2 and at the occurrence of an adverse outcome such as anemia, hypotension, arrhythmia, hypoxia, fever with or without chills
Results: Forty-five patients were included in this prospective study. Forty patients had 63 events: low cardiac output, isolated hypotension, hypoxia, anemia, AFib and atrial flutter. There was no statistically significant difference in StO2 from pre-induction till up to 2 days postoperatively, except after the weaning from CPB and 12 hours postoperatively. No correlation was noted between SvO2 and StO2 during the events that occurred both during and after the operation
Conclusion: Microcirculation at the eminence thenar may be altered after CPB. This fact is reflected by the decrease in StO2 that was noted immediately after CPB and that returned to normal 12 hours postoperatively. However, StO2 is not correlated with SvO2 upon the occurrence of an event during or after elective cardiac surgery. Further studies are needed to show the benefit of this noninvasive monitoring in cardiac surgery