Myocardial injury during non-cardiac surgery using mid flow and minimal flow anesthesia

Cardiovascular events are the most important cause of mortality and morbidity after non-cardiac surgery. Myocardial injury after non-cardiac surgery (MINS) is an asymptomatic condition seen in the postoperative period, diagnosed only by troponin elevation, and is closely associated with postoperative mortality. Low-flow anesthesia techniques provide advantages in terms of their positive effect on environmental conditioning, cost-reducing effect, and preservation of intraoperative physiological respiratory conditions. In our study, we aimed to evaluate the effects of different fresh gas flow applications on the development of MINS in patients undergoing total knee arthroplasty surgery. In our prospective, randomized controlled clinical study, after receiving ethics committee approval, the study was completed with a total of 90 patients who gave their written consent between 11/06/2024 and 13/12/2024. Patient's age, gender, ASA score, accompanying comorbidities, fresh gas flows applied to the patients, hemodynamic parameters, FiO2, FiCO2, end-tidal CO2, MAC (Minimal Alveolar Concentration), Patient State Index (PSI) values while the patients were connected to mechanical ventilation, preoperative 24-hour troponin values, postoperative 6th, 12th, 24th, 48th and 72th hours troponin values, postoperative 30-day adverse events and mortality rates were recorded. According to the fresh gas flow rate applied during the operation, the patients were divided into 2 groups: Midflow (2 L/min) and Minimal flow (0.5 L/min). Different fresh gas flows were applied to the patients and the postoperative MINS development status was evaluated prospectively. When the rates of MINS seen in the postoperative period were compared between the groups, it was found that the incidence of MINS was higher in patients who received mid-flow anesthesia than in patients who received minimal-flow anesthesia. In conclusion, considering the advantages of low-flow anesthesia and the findings of our study, we believe that minimal-flow anesthesia can be safely applied in patients undergoing total knee arthroplasty in terms of postoperative MINS development. Keywords: Low-flow anesthesia, MINS, Total knee arthroplasty