The Effect of Continuous Low Tidal Volume Ventilation During Cardiopulmonary Bypass on Renal Resistive Index

Postoperative acute kidney injury following cardiopulmonary bypass surgery represents a significant barrier to patient recovery and is closely associated with increased postoperative morbidity and mortality. Studies have shown that the incidence of AKI after CABG ranges between 5% and 30%.

The Renal Resistive Index, measured by Doppler ultrasonography, is an increasingly utilized parameter that provides valuable insights into renal hemodynamics and vascular resistance. A normal RRI is typically below 0.70; elevated values may indicate increased renal vascular resistance or microvascular damage. Bossard et al. demonstrated that increased RRI in the early postoperative period is associated with the development of AKI. Early evaluation of renal blood flow thus facilitates prompt detection of AKI. Both preoperative and postoperative RRI measurements are considered useful tools for identifying early renal dysfunction. Monitoring RRI before and after CABG may provide critical information for preventing postoperative renal complications.In recent years, significant advancements have been made in both surgical and anesthetic techniques in cardiac surgery. During CABG, the commonly used ventilation strategy during cardiopulmonary bypass is apneic ventilation. However, low tidal volume ventilation has been proposed as an alternative, with a growing body of literature supporting its use. LTV has been associated with reduced postoperative pulmonary complications, earlier extubation, and prevention of atelectasis and pulmonary edema.

Inclusion criteria

• Patients scheduled for elective cardiac bypass surgery
• Male and female patients over 18 years of age
• Patients with an American Society of Anesthesiologists (ASA) physical status classification of II, III, or IV

Exclusion criteria

• Chronic renal failure requiring dialysis
• Patients requiring emergency surgery