Objectives: This study aimed to assess whether continuous furosemide administration during cardiopulmonary bypass (CPB) in minimally invasive cardiac surgery (MICS) reduces the incidence of cardiac surgery-associated acute kidney injury (AKI). 

Methods: A total of 100 patients undergoing MICS with CPB were randomly assigned to receive either continuous furosemide infusion or no continuous furosemide during CPB. The primary endpoint was the incidence of AKI. Secondary endpoints included the cardiac surgery-associated neutrophil gelatinase-associated lipocalin (CSA-NGAL) score, urine output within 12 h postoperatively, postoperative furosemide dose requirements, red blood cell transfusion volume, PaO₂/FiO₂ ratio, duration of mechanical ventilation, length of stay in the intensive care unit (ICU) and hospital, and in-hospital mortality. 

Results: AKI occurred in 8 patients (16%) in the continuous furosemide group and in 6 patients (12%) in the non-continuous group (relative risk, 0.72; 95% CI, 0.23–2.23). Among the secondary endpoints, urine output within the first 3 h postoperatively and the PaO₂/FiO₂ ratio were significantly higher in the continuous furosemide group. However, subgroup analyses revealed no significant differences between the two groups. 

Conclusions: Continuous furosemide administration during CPB did not effectively reduce the incidence of AKI. However, it was associated with a significant increase in postoperative urine output and an improvement in the PaO₂/FiO₂ ratio.