Continuous Monitoring of Lactate Using Intravascular Microdialysis in High-Risk Cardiac Surgery: A Prospective Observational Study

Objective: To assess the accuracy and applicability of a novel system, not requiring calibration, for continuous lactate monitoring with intravascular microdialysis in high-risk cardiac surgery. Design: Single-center prospective observational study. Setting: City Hospital 1 of Arkhangelsk, Russian Federation. Participants: Twenty-one adult patients undergoing elective complex repair or replacement of two or more valves or combined valve and coronary artery cardiac surgery. Interventions: After induction of anesthesia, in all patients a dedicated triple-lumen catheter functioning as a regular central venous catheter with integrated microdialysis function was inserted via the right jugular vein for continuous lactate monitoring using the intravascular microdialysis system. Measurements and Main Results: Lactate values displayed by the microdialysis system were compared with the reference arterial blood gas (ABG) values. In total, 432 paired microdialysis-ABG lactate samples were obtained. After surgery, the concentration of lactate increased significantly, peaking at 8 hours (p < 0.05). The lactate clearance within 8 hours after peak concentration was 50% (39%-63%). There was a significant correlation between Lactate., and Lactate,, (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 patients with postoperative complications, peak lactate concentration was significantly higher compared with those without complications: 6.75 (4.43-7.75) mmol/L, versus 4.20 (3.95-4.87) mmol/L (p = 0.002). Conclusions: Lactate concentration increased significantly after high-risk cardiac surgery. The intravascular microdialysis technique for lactate measurement provided acceptable accuracy and can be used for continuous blood lactate monitoring in cardiac surgery. (C) 2017 Elsevier Inc. All rights reserved.