Gastric Reactance as a Marker for Major Perioperative Complications in High-Risk Cardiac Surgery Patients Undergoing Cardiopulmonary Bypass

Maria de Montserrat Godinez-Garcia^1*Yazmin Guillen-Dolores²Adrian Soto-Mota³Rolando Alvarez⁴Edgar Garcia⁴Ruben Gaitan⁵Carlos Sanchez⁵Ericka Chavez¹Alonso Buitano⁵Ma del C. Lespron²Francisco J. Molina²Solange Gabriela Koretzky⁴Sergio Camacho⁶Antonio Gordillo-Moscoso⁷

• ¹Department of Clinical Research, Alandra Medical SAPI de CV, Mexico City, Mexico
• ²Department of Anesthesiology, National Institute of Cardiology Ignacio Chavez, Mexico City, Mexico
• ³Department of Research, Metabolic Diseases Research Unit, National Institute of Medical Sciences and Nutrition Salvador Zubiran, Mexico City, Mexico
• ⁴Department of Cardiovascular Intensive Care, National Institute of Cardiology Ignacio Chavez, Mexico City, Mexico
• ⁵Department of Biomedical Engineering, Alandra Medical SAPI de CV, Mexico City, Mexico
• ⁶Faculty of Sciences, Department of Biomedical Engineering, Autonomous University of San Luis Potosi, San Luis Potosi, Mexico
• ⁷Faculty of Medicine, Department of Clinical Epidemiology, Autonomous University of San Luis Potosi, San Luis Potosi, Mexico

Gastric reactance (XL) is a bioelectrical property of the stomach lining that responds to changes in gut perfusion. It is measured through bioimpedance spectroscopy, a technology that assesses the tissue's electrical resistance and capacity to store electrical charge, providing insight into the physiological state of the gastric mucosa. This prospective observational study explored the relationship between XL and hemodynamic variables in high-risk adult patients undergoing elective cardiac surgery with cardiopulmonary bypass (CPB) at the National Institute of Cardiology, Mexico City. Thirty-seven patients were enrolled and categorized according to the development of major perioperative complications (MPOC; n=23) or absence thereof (Non-MPOC; n=14). Baseline demographic and intraoperative variables did not differ significantly between groups. However, the MPOC group exhibited higher postoperative severity scores (APACHE II: 21.5 vs. 18.5, p=0.231; SOFA: 12.5 vs. 12.0, p=0.249) and greater postoperative bleeding (1.0 L vs. 0.4 L, p<0.001). XL minimum values (XL_Min) were consistently elevated in the MPOC group throughout all perioperative events, with a significant shift of 6.14 -jΩ (95% CI [1.06, 11.34], p=0.022) in Post-CPB. These findings suggest that gastric impedance spectroscopy is a safe and feasible technique for intraoperative and postoperative monitoring, and that elevated XL_Min values may aid in the early identification of patients at risk for MPOC by detecting gastric mucosal hypoperfusion during high-risk cardiac surgery.