Background: In this study, we aimed to identify the potential period which microcirculation tends to mostly deteriorate and other hemodynamic and arterial blood gas parameters associated with microcirculation in patients undergoing elective open heart surgery with extracorporeal circulation.

Methods: Twenty adult patients (12 males, 8 females; mean age 56.4 years; range 38 to 77 years) who were scheduled for elective first-time open heart surgery were prospectively included in the study. Tissue oxygen saturation heart rate, pulse oximetry, electrocardiography, invasive arterial blood pressure monitoring, bispectral index, and regional cerebral oxygen saturation monitoring were performed. Measurements were repeated and recorded before anesthesia induction, preoperatively, and postoperatively.

Results: The lowest tissue oxygen saturation values and the highest % alteration of the right and left regional cerebral oxygen saturation were in the re-warming period perioperatively with 69±2%, –17±2%, –14±2%, respectively. The lowest values in postoperative period were measured at the postoperative first hour with 59±2%, –15±4%, –12±3%, respectively. Reductions in the tissue oxygen saturation, lactate and regional cerebral oxygen saturation values were statistically significantly correlated with each other (p<0.05).

Conclusion: Hypotermia, hemodilution and nonpulsatile flow during and after extracorporeal circulation may deteriorate microcirculation; however, standard monitoring variables may fail to detect this deterioration timely. We believe that microcirculation evaluation with standard monitorization with the addition of tissue oxygen saturation monitorization may be of significance for the outcome variables.

Keywords : Extracorporeal circulation; microcirculation; tissue oxygen saturation