Association of intraoperative blood gas analysis with patient outcome after adult cardiac surgery

Abstract

Background: The associations of the different blood gas parameters from different blood samples harvested at different stages during adult cardiac surgery with the postoperative outcomes are inadequately studied. Methods: Adult patients undergoing elective cardiac surgery with cardiopulmonary bypass (CPB) participated in this prospective observational study. Blood gas parameters from arterial, central venous, and jugular bulb venous blood samples harvested simultaneously at pre-determined time points (baseline with the patient awake, post-anesthesia induction but before CPB, during CPB at 30°C, during CPB at 37°C (rewarming), and at the end of surgery) were correlated with postoperative outcomes including the length of mechanical ventilation (LMV), intensive care unit stay (LICU), hospital stay (LOH), and major organ morbidity and mortality. Results: Data from 193 patients were analyzed. Multiple parameters of different blood harvested at different stages significantly correlated with one or more outcome measures based on univariate analysis (p < 0.05). However, only the jugular bulb venous blood pH and carbon dioxide tension and the central venous blood pH at the end of surgery (pHcv-end) were significantly correlated with LMV, LICU, and LOH (p < 0.05). A more alkaline blood correlated with more favorable outcomes. After adjusting for age, surgical time, and total intravenous volume administered, multivariate analysis showed that only pHcv-end remained independently associated with LMV and LICU (p < 0.05). Conclusion: More alkaline blood, especially the central venous blood at the end of surgery, is associated with more favorable outcomes after adult cardiac surgery. Trial registration ChiCTR-POC-17013942, Date of registration December 15, 2017.