Intraoperative myocardial acidosis as a risk for hospital readmission after cardiac surgery

Background: This study elucidates the relationship between intraoperative myocardial acidosis/ischemia and the risk of unplanned hospital readmissions within 30 days and 6 months after cardiac surgery. Methods: Myocardial tissue pH (corrected to 37°C: pH_37C) was monitored in 221 patients during cardiac surgery. Regional myocardial acidosis was defined in terms of specific pH thresholds. Results: Fourteen percent and 27% of the patients were readmitted within 30 days and 6 months postoperatively, respectively. The mean number of readmissions was 1.67 ± 1.24; pH_37C <6.85 at the end of cardiopulmonary bypass (CPB) was identified as the threshold most significantly associated with readmission. This threshold was associated with a 6-fold increased risk of readmission within 30 days and a 5-fold increased risk within 6 months. Conclusions: Persistent regional myocardial acidosis after weaning from CPB independently determines unplanned readmission rates up to 6 months postoperatively. This study underscores the importance of avoiding myocardial tissue acidosis during cardiac surgery.