Prognostic value of serum lactate during anesthesia for cardiac surgery.

Abstract

Background:During cardiac surgery, CPB machine pumps blood instead of the heart affecting blood flow and hence blood perfusion of all tissues. One important marker of blood perfusion is central venous oxygen saturation. Relationship between central venous oxygen saturation and patient morbidity and mortality is an indicator for the reliability of blood lactate as a perfusion marker. Objectives: This study aimed to assess the value of monitoring of central venous oxygen saturation in postoperative prognosis. The primary outcome was ICU length of stay, while the secondary outcomes were both duration of mechanical ventilation and postoperative complications. Methods: In a prospective observational study, 66 patients admitted to Sohag university hospital and Sohag Heart Institute in the period between October 2017 and April 2019 for open cardiac surgery were enrolled. Immediately after induction of anesthesia, the first sample of venous blood gas was obtained from central venous catheter. For measuring of central venous oxygen saturation, the next samples were obtained just before CPB weaning, the next after 24 hours of staying ICU and the last sample were obtained after 48 hours of staying ICU. Results: Central venous oxygen saturation in correlation to ICU length of stay showed patients stayed in the ICU less than 48 hours had significant p-value <0.001 and patients stayed in the ICU more than 48 hours had a non-significant p-value 0.693 indicating more significant change in central venous oxygen saturation in patients with favorable outcome. Central venous oxygen saturation in correlation to postoperative duration of mechanical ventilation showed patients stayed on mechanical ventilation less than 12 hours had significant p-value 0.004 and patients stayed on mechanical ventilation more than 12 hours had a non-significant p-value 0.724 indicating more significant change in central venous oxygen saturation in patients with favorable outcome. Central venous oxygen saturation in correlation to postoperative complications showed patients without postoperative complications had significant p-value 0.001 and patients with postoperative complications had a non-significant p-value 0.436 indicating more significant change in central venous oxygen saturation in patients with favorable outcome. Conclusion: Measuring ScvO2 at 4 points during and after open-heart surgery showed their prognostic value, regarding results for ScvO2: ICU length of stay, duration of mechanical ventilation and complications.