[Effect of sodium bicarbonate Ringer's solution on postoperative acute kidney injury in patients undergoing off-pump coronary artery bypass grafting].

<b>Objective:</b> To explore the effect of sodium bicarbonate Ringer's solution on postoperative acute kidney injury (AKI) in elderly patients undergoing off-pump coronary artery bypass grafting (OPCABG). <b>Methods:</b> The medical records of patients undergoing elective OPCABG at Tianjin Chest Hospital, Tianjin University, between September 2021 and October 2023 were retrospectively reviewed. The inclusion criteria were as follows: age ≥65 years, body mass index (BMI) of 18 to 30 kg/m², and American Society of Anesthesiologists (ASA) physical status class Ⅲ-Ⅳ. Patients were allocated to either the sodium bicarbonate Ringer's solution group or the compound electrolyte solution group (control group) based on the type of intraoperative crystalloid administered. Potential confounders were adjusted using propensity score matching (PSM) and multivariable logistic regression models. The primary outcome was the incidence of AKI within 7 days postoperatively. <b>Results:</b> A total of 868 patients aged (69±5) years were included in the final analysis, with 591 males and 277 females. Postoperative AKI occurred in 105 patients (12.1%). After PSM, there were no statistically significant differences in baseline characteristics and intraoperative variables between the two groups (all <i>P</i>>0.05). Multivariable logistic regression analyses demonstrated that, intraoperative use of sodium bicarbonate Ringer's solution was a protective factor against postoperative AKI following OPCABG (<i>OR</i>=0.52, 95%<i>CI</i>: 0.28-0.97, <i>P</i>=0.040). <b>Conclusion:</b> Compared with compound electrolyte solution, use of sodium bicarbonate Ringer's solution during surgery is associated with a lower risk of AKI after OPCABG.