Impact of intraoperative myocardial tissue acidosis on postoperative adverse outcomes and cost of care for patients undergoing prolonged aortic clamping during cardiopulmonary bypass

Background: This study examined the impact of intraoperative myocardial acidosis and adverse postoperative outcomes on the cost of cardiac surgical care. Methods: Myocardial tissue pH corrected to 37°C (pH_37C) was measured in 162 patients with cross-clamp (XC) duration of 119 minutes or longer. Perioperative data and outcomes were collected prospectively. The Veterans Affairs cost accounting system was used to determine the cost of care in a subset of 57 patients. Results: Long XC duration was associated with significantly increased acidosis and adverse postoperative outcomes. The cost of care for patients with adverse outcomes was increased by 110% (P < .0001). Patients with acidosis at the end of reperfusion had significantly (P = .0470) increased costs of care. End reperfusion of myocardial tissue pH_37C of less than 7.0, diabetes mellitus, and body surface area were significant determinants of postoperative adverse outcomes. Conclusions: Intraoperative myocardial acidosis is a determinant of postoperative adverse outcomes and cost in cardiac surgery. Reducing XC duration and improving intraoperative myocardial protection should improve outcomes and reduce cost.