Abstract PR033

Abstract

Background & Objectives: Increased lactate levels after heart surgery are associated with postoperative morbidity and prolonged length of ICU stay. The aim of our study was to assess the accuracy and applicability of a novel system for continuous lactate monitoring with intravascular microdialysis not requiring calibration in high-risk cardiac surgery. Materials & Methods: Twenty-one patients undergoing elective complex (repair or replacement of two or more valves) or combined (valve and coronary artery) cardiac surgery were enrolled into a prospective observational pilot study. In all patients continuous lactate monitoring was performed using a triple-lumen central venous catheter with an integrated intravascular microdialysis function. Lactate concentration was measured using EirusTM intravascular microdialysis system (Lactatecont) and compared to the lactate concentration in the arterial blood (Lactateart) at 15 stages during the surgery and postoperatively. Results: In total, 432 paired microdialysis–arterial blood gas lactate samples were obtained. After surgery, the concentration of lactate increased significantly peaking at 8 hrs (p < 0.05). The lactate clearance within 8 hrs after peak concentration was 50 (39–63) %. There was a significant correlation between Lactatecont and Lactateart (rho = 0.92, p < 0.0001). Bland-Altman analysis showed a bias (mean difference) ± limits of agreement (±1.96 SD) of 0.09 ± 1.1 mmol/L. In addition, we found a correlation between the lactate concentration in the central venous blood with the central venous-to-arterial carbon dioxide difference (rho = 0.35, p < 0.05) and mean arterial pressure (rho = –0.21, p < 0.001). We did not observe any relationship between lactate concentration, cardiac index, and ScvO2. In patients with postoperative complications, the median and the maximum lactate concentrations were 2.92 (1.75 – 3.50) and 6.75 (4.43 – 7.75) mmol/L, respectively, vs. 2.36 (1.50 – 3.00) and 4.20 (3.95 – 4.87) mmol/L in patients without complications (p = 0.002). Conclusion: Lactate concentration increases significantly after high-risk cardiac surgery. The intravascular microdialysis technique for lactate measurement provides acceptable accuracy and can be used for continuous blood lactate monitoring in open-heart surgery. Disclosure of Interest: None declared